(19)
(11) EP 0 902 737 B9

(12) CORRECTED EUROPEAN PATENT SPECIFICATION
Note: Bibliography reflects the latest situation

(15) Correction information:
Corrected version no 1 (W1 B1)
Corrections, see
Bibliography

(48) Corrigendum issued on:
08.10.2008 Bulletin 2008/41

(45) Mention of the grant of the patent:
02.01.2008 Bulletin 2008/01

(21) Application number: 96940909.3

(22) Date of filing: 29.11.1996
(51) International Patent Classification (IPC): 
H01M 6/12(2006.01)
H01M 6/46(2006.01)
H01M 10/26(2006.01)
H01M 6/22(2006.01)
H01M 4/24(2006.01)
(86) International application number:
PCT/US1996/019048
(87) International publication number:
WO 1997/022466 (26.06.1997 Gazette 1997/27)

(54)

FLEXIBLE THIN LAYER OPEN ELECTROCHEMICAL CELL

FLEXIBLE DÜNNE SCHICHT FÜR OFFENE ELEKTROCHEMISCHE ZELLE

CELLULE ELECTROCHIMIQUE DE CONFIGURATION OUVERTE, A COUCHE MINCE FLEXIBLE


(84) Designated Contracting States:
AT BE DE ES FI FR GB GR IE IT NL PT SE

(30) Priority: 20.12.1995 US 575190

(43) Date of publication of application:
24.03.1999 Bulletin 1999/12

(73) Proprietors:
  • Power Paper Ltd.
    49130 Petah Tikva (IL)
    Designated Contracting States:
    AT BE DE ES FI FR GB GR IE IT NL PT 
  • PowerID Ltd.
    49170 Petah Tikva (IL)
    Designated Contracting States:
    SE 

(72) Inventor:
  • NITZAN, Zvi
    49600 Petach Tikva (IL)

(74) Representative: McCarthy, Denis Alexis et al
MacLachlan & Donaldson 47 Merrion Square
Dublin 2
Dublin 2 (IE)


(56) References cited: : 
EP-A- 0 456 122
US-A- 4 119 770
US-A- 5 019 467
US-A- 3 901 732
US-A- 4 195 121
   
     
    Remarks:
    The file contains technical information submitted after the application was filed and not included in this specification
     
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD AND BACKGROUND OF THE INVENTION



    [0001] The present invention relates to electrochemical cells which are used as battery power sources by converting chemical energy to electrical energy. More particularly, the present invention relates to a primary or rechargeable electrochemical cell to be used as a regular or rechargeable battery which accomplishes the conversion of chemical energy to electrical energy using a wet (e.g., liquid state) electrolyte, yet maintain a flexible thin layer and open configuration.

    [0002] The ever-growing development of miniaturized and portable electrically powered devices of compact design such as, for example, cellular phones, voice recording and playing devices, watches, motion and still cameras, liquid crystal displays, electronic calculators, IC cards, temperature sensors, hearing aids, pressure sensitive buzzers, etc., generates an ever-growing need of compact thin layer batteries for their operation. Therefore, there is a need for reliable thin layer electrochemical cells to be used as batteries.

    [0003] Batteries can be broadly classified into two categories in which the batteries of the first category include wet electrolytes (i.e., liquid state batteries), whereas batteries of the second category include solid state electrolyte. Although solid state batteries have an inherent advantage, they do not dry out and do not leak, they suffer major disadvantages when compared with liquid state batteries since, due to limited diffusion rates of ions through a solid, their operation is temperature dependent to a much larger extent, and many operate well only under elevated temperatures; and, the limited diffusion rates thus described, characterize solid state batteries with low ratio of electrical, energy generated. vs. their potential chemical energy. Liquid state thin layer, batteries typically include a positive and negative active insoluble material layer put together with a separator interposed therebetween, which separator is soaked with a liquid electrolyte solution, thus functioning as an electrolytic liquid layer. Such batteries, an example of which is disclosed for example in U.S. Pat. No. 4,623,598 to Waki et al., and in Japanese Pat. No. JP 61-55866 to Fuminobu et al., have to be sealed within a sheathing film to prevent liquid evaporation, and are therefore closed electrochemical cells. Being closed cells, these batteries tend to swell upon storage due to evolution of gases which is a fatal problem in thin layer batteries having no mechanical support, the pressure imposed by the accumulated gases leads to layer separation, thus turning the battery inoperative. Means to overcome this problem include (1) the use of a polymer increased viscosity agent, such as hydroxyethylcellulose, applied to adhere (i.e., glue) the battery layers together, thus to overcome the inherent problem of such batteries imposed by lack of solid support; and, (2) addition of mercury to prevent the formation of gases, especially hydrogen. However, the polymer is limited in its effectiveness and the mercury is environmental hazardous.

    [0004] A way to solve the above described limitation was disclosed in U.S. Pat. No. 3,901,732 to Kis et al. in which a gas-permeable electrolyte-impermeable polymeric material which allows venting of undesirable gases formed within the battery while preventing any electrolyte loss from the battery is used as a sheathing film to enclose the battery cell.

    [0005] However, a more direct and efficient way to avoid undesired gas accumulation in liquid state thin layer batteries would be to provide these batteries as open cells for facilitated release of gases, while at the same time to provide means to avoid liquid evaporation and drying out of the battery.

    [0006] European patent specification no. EP 0 456 122 discloses a galvanic Leclanche type cell. A transdermal therapeutic system is disposed which is built up in layers and has an electrically insulating backing layer which is impermeable to active substance, and two galvanic elements which are arranged in a manner insulated from one another. The skin-side electrodes of the galvanic elements bear layers and the layer of at least one of the skin-side electrodes contains a pharmaceutical active substance. Moisture may diffuse into the cell at activation. EP 0 456 122 does not disclose a galvanic cell including a deliquescent material to keep the cell wet at all times.

    [0007] There is a widely recognized need for, and it would be highly advantageous to have, a flexible thin layer open electrochemical cell devoid of both accumulation of gases and liquid evaporation limitations.

    SUMMARY OF THE INVENTION



    [0008] According to the present invention there is provided an open electrochemical cell which can be used as a primary or rechargeable power supply for various miniaturized and portable electrically powered devices of compact design. There is further provided a method of manufacturing such a cell. The flexible thin layer open electrochemical cell of the present invention includes a wet electrolyte, yet maintains a flexible, thin and open configuration, thus devoid of accumulation of gases upon storage.

    [0009] According to further features in preferred embodiments of the invention described below, the cell comprising a first layer of insoluble negative pole, a second layer of insoluble positive pole and a third layer of aqueous electrolyte, the third layer being disposed between the first and second layers and including: (a) a deliquescent material for keeping the open cell wet at all times; (b) an electroactive soluble material for obtaining required ionic conductivity; and, (c) a watersoluble polymer for obtaining a required viscosity for adhering the first and second layers to the third layer.

    [0010] According to still further features in the described preferred embodiments, the electrolyte layer is engaged by a porous substance.

    [0011] According to still further features in the described preferred embodiments, the porous substance is selected from the group consisting of a filter paper, a plastic membrane, a cellulose membrane and a cloth.

    [0012] According to still further features in the described preferred embodiments the first layer of insoluble positive pole includes manganese-dioxide powder and the second layer of insoluble negative pole includes zinc powder.

    [0013] According to still further features in the described preferred embodiments the first layer of insoluble negative pole and/or the second layer of insoluble positive pole further includes carbon powder and the electroactive soluble material is selected from the group consisting of zinc-chloride, zinc-bromide, zinc-fluoride and potassium-hydroxide.

    [0014] According to still further features in the described preferred embodiments the first layer of insoluble negative pole includes silver-oxide powder and the second layer of insoluble positive pole includes zinc powder and the electroactive soluble material is potassium-hydroxide.

    [0015] According to still further features in the described preferred embodiments the first layer of insoluble negative pole includes cadmium powder and the second layer of insoluble positive pole includes nickel-oxide powder and the electroactive soluble material is potassium-hydroxide.

    [0016] According to still further features in the described preferred embodiments the first layer of insoluble negative pole includes iron powder and the second layer of insoluble positive pole includes nickel-oxide powder and the electroactive soluble material is potassium-hydroxide.

    [0017] According to still further features in the described preferred embodiments the first layer of insoluble negative pole and the second layer of insoluble positive pole include lead-oxide powder, the cell is charged by voltage applied to the poles and the electroactive soluble material is sulfuric-acid.

    [0018] According to still further features in the described preferred embodiments the deliquescent material and the electroactive soluble material are the same material and are selected from the group consisting of zinc-chloride, zinc-bromide, zinc-fluoride and potassium-hydroxide.

    [0019] According to still further features in the described preferred embodiments the deliquescent material is selected from the group consisting of calcium-chloride, calcium-bromide, potassium-biphosphate and potassium-acetate.

    [0020] According to still further features in the described preferred embodiments the watersoluble polymer is selected from the group consisting of polyvinylalcohol, poliacrylamide, polyacrylic acid, polyvinylpyrolidone, polyethylenoxide, agar, agarose, starch, hydroxyethylcellulose and combinations and copolymers thereof.

    [0021] According to still further features in the described preferred embodiments the watersoluble polymer and the deliquescent material are the same material and are selected from the group consisting of dextrane, dextranesulfate and combinations and copolymers thereof.

    [0022] According to still further features in the described preferred embodiments the cell further comprising terminals, each of the terminals being in electrical contact with one of the first and second pole layers.

    [0023] According to still further features in the described preferred embodiments the terminal are made of graphite or a metal.

    [0024] According to still further features in the described preferred embodiments the metal is selected from the group consisting of iron, nickel, titanium, copper, stainless steel and mixtures thereof, and the terminals are applied to the cell by a suitable printing technology such as, but not limited to, silk print, offset print, jet printing, lamination, materials evaporation or powder dispersion.

    [0025] According to still further features in the described preferred embodiments the cell further comprising at least one conductive layer improving the electronic conductivity of at least one of the first and second pole layers.

    [0026] According to still further features in the described preferred embodiments the conductive layer is selected from the group consisting of a graphite paper and carbon cloth.

    [0027] According to still further features in the described preferred embodiments, the cell further comprises an external layer selected from the group consisting of an adhesive backing layer, a lamina protective layer and a combination of adhesive backing layer and a lamina protective layer.

    [0028] According to still further features in the described preferred embodiments provided is an electrical power supply comprising at least two cells featured as above, the cells are connected in a head to tail orientation in a bipolar-connection.

    [0029] According to still further features in the described preferred embodiments, the connection is by an adhesive selected from the group consisting of a conductive double sided adhesive tape and a conductive glue layer.

    [0030] According to still further features in the described preferred embodiments, the conductive double sided adhesive tape and the conductive glue layer are applied by a printing technology.

    [0031] According to still further features in the described preferred embodiments, the cell comprises a first layer of insoluble negative pole, a second layer of insoluble positive pole and a third layer of aqueous electrolyte, the third layer being disposed between the first and second layers and including: (a) a watersoluble polymer for obtaining a required viscosity for adhering the first and second layers to the third layer and for obtaining a required hygroscopicality for keeping the open cell wet at all times; and (b) an electroactive soluble material for obtaining a required ionic conductivity.

    [0032] According to still further features in the described preferred embodiments, the method of making an open electrochemical cell comprises the steps of (a) wetting a porous substance having a first side and a second side with an aqueous solution containing a deliquescent material, an electroactive soluble material and a watersoluble polymer; (b) applying onto the first side a layer of negative pole; and (c) applying onto the second side a layer of positive pole.

    [0033] According to still further features in the described preferred embodiments the wetting is by a dipping or printing technologies.

    [0034] According to still further features in the described preferred embodiments the layers of negative and positive poles include active insoluble powder materials mixed with the deliquescent material, electroactive soluble material and watersoluble polymer, the application of the layers of negative and positive poles is by a printing technology.

    [0035] The present invention successfully addresses the shortcomings of the presently known configurations by providing a flexible thin layer open electrochemical cell which does not accumulate gases upon storage, yet it is maintained wet and intact by the use of a deliquescent material for keeping it wet at all times and a watersoluble polymer for obtaining the required viscosity for adhering the pole layers to the aqueous electrolyte layer. Further qualities of the cell include having no outer rigid casting therefore it is thin light and flexible and may be manufactured in any size, shape, color and applied patterns, hence it is suitable for a variety of applications; cost effectiveness; made of environmental and human friendly materials; and, self sticking via an adhesive backing.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0036] The invention herein described, by way of example only, with reference to the accompanying drawings, wherein:

    FIG. 1 is a perspective view of a basic configuration of a flexible thin layer open electrochemical cell according to the teachings of the present invention;

    FIG. 2 is a is a perspective view of another possible configuration of a flexible thin layer open electrochemical cell;

    FIGs. 3a and 3b are perspective views of two possible configurations of power supplies formed by a a bi-polar connection of two cells of Figure 1 and Figure 2, respectively, to additively increase the electrical energy obtained of thus formed electrical power supplies; and

    FIG. 4 is a graph presenting the voltage of a flexible thin layer open electrochemical cell according to the present invention, as measured by a voltmeter, as function of time, under room conditions.


    DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0037] The present invention is of a flexible thin layer open electrochemical cell which can be used as a primary or rechargeable power supply for various miniaturized and portable electrically powered devices of compact design. The flexible thin layer open electrochemical cell of the present invention includes a wet electrolyte, yet maintains a flexible, thin and open configuration, thus devoid of accumulation of gases upon storage.

    [0038] The principles and operation of a flexible thin layer open electrochemical cell according to the present invention may be better understood with reference to the drawings and accompanying descriptions.

    [0039] Referring now to the drawings, Figure 1 illustrates a basic configuration of the flexible thin layer open electrochemical cell of the present invention, generally designated 10. Cell 10 includes three layers as follows. A first layer of insoluble negative pole 14, a second layer of insoluble positive pole 16 and a third layer of aqueous electrolyte 12. As used in this document, on discharged negative pole is where an oxidation occurs, whereas the positive pole is where reduction occurs. The aqueous electrolyte layer 12 includes a deliquescent (i.e., hygroscopic) material for keeping open cell 10 wet at all times; an electroactive soluble material for obtaining the required ionic conductivity; and a watersoluble polymer for obtaining the required viscosity for adhering pole layers 14 and 16 to aqueous electrolyte layer 12. Following is a more detailed description of each of layers 14, 16 and 12 and their role in open cell 10 operation.

    [0040] The aqueous electrolyte layer 12 typically includes a porous insoluble substance, such as but not limited to, filter paper, plastic membrane, cellulose membrane, cloth, etc., the porous substance is wetted by an aqueous solution including three components: a deliquescent material, an electroactive soluble material; and a watersoluble polymer.

    [0041] The deliquescent material by being hygroscopic maintains cell 10 moisturized at all times. The level of moisture within open cell 10 may vary depending on deliquescent material selection, its concentration and air humidity. Suitable deliquescent materials include, but are not limited to, calcium-chloride, calcium-bromide, potassium-biphosphate, potassium-acetate and combinations thereof.

    [0042] The electroactive soluble material is selected in accordance with the materials of which the negative and positive pole layers are made. A list of frequently used electro active soluble materials suitable for the present invention includes for example zinc-chloride, zinc-bromide and zinc-fluoride for various primary cells and potassium-hydroxide and sulfuric-acid for rechargeable cells.

    [0043] The watersoluble polymer is employed as an adhesive agent to adhere (i.e., glue) pole layers 14 and 16 to the aqueous electrolyte layer 12. Many types of polymers are suitable ones, such as for example polyvinylalcohol, poliacrylamide, polyacrylic acid, polyvinylpyrolidone, polyethylenoxide, agar, agarose, starch, hydroxyethylcellulose and combinations and copolymers thereof.

    [0044] Each of negative and positive pole layers 14 and 16 includes a mix of a suitable (negative or positive, respectively) active insoluble powder material with an aqueous solution similar to the solution described hereinabove, including a deliquescent material; an electroactive soluble material; and a watersoluble polymer.

    [0045] It is clear to those with skills in the art that while the electroactive soluble material should not change, the deliquescent material and the watersoluble polymer may be selected otherwise in the later solution, in other words, the electroactive soluble material should be kept the same in all three layers 12, 14 and 16, whereas the deliquescent material and the watersoluble polymer may be varied between layers according to the specific application.

    [0046] Appropriate selection of active insoluble powder materials for the negative 14 and positive 16 pole layers with a matching electroactive soluble material, as exemplified hereinbelow in the Examples, provides flexible thin layer cell 10 which can be used as a power supply (i.e., a battery), which cell 10 is open and therefore does not accumulate gases upon storage, yet the hygroscopicality of the deliquescent material ensures that cell 10 is kept wet at all times although open. Suitable pairs of materials to be used in negative 14 and positive 16 poles include, but are not limited to, manganese-dioxide/zinc; silver-oxide/zinc; cadmium/nickel-oxide; and iron/nickel-oxide (the manganese-dioxide and the silver-oxide are optionally mixed with a conductive carbon powder as known in the art).

    [0047] It is clear to those with skills in the art that a single material may function both as a deliquescent material and as the electroactive soluble material. Such a material should however acquire suitable electroactive and hygroscopic characteristics. Suitable materials of this type include, but are not limited to, zinc-chloride and zinc-bromide.

    [0048] It is further clear to those with skills in the art that a single material may function as a deliquescent material and as a watersoluble polymer. Such a material should however acquire suitable hygroscopic and adhesivness characteristics. Suitable materials of this type include, but are not limited to, dextrane, dextranesulfate and combinations and copolymers thereof.

    [0049] The three layers 12, 14 and 16, presented in Figure 1 and described hereinabove may be manufactured thin and are flexible, therefore cell 10 is flexible and as thin as 0.5-1.5 mm or less. It is presently preferred and will be further detailed below that cell 10 will be manufactured by a suitable printing technology. Suitable printing technologies include, but are not limited to, silk print, offset print, jet printing, lamination, materials evaporation and powder dispersion.

    [0050] Another possible configuration is shown in Figure 2 illustrating a cell, generally assigned 20. As cell 10, cell 20 also includes layers 12, 14 and 16 (stripped region) forming a basic cell. Cell 20 further includes additional one or two conductive layers 22 and 24, to improve the electronic conductivity of negative 14 and/or positive 16 pole layers. Suitable conductive layers are graphite paper, carbon cloth, etc. Cell 20 also includes negative 26 and positive 28 terminals, which terminals 26 and 28 are in electrical contact with either the corresponding pole layer 14 and 16, respectively, or with the corresponding conductive layer 22 and 24, respectively, or both. Terminals 26 and 28 are made of any suitable materials such as, but not limited to, graphite or metals such as iron, nickel, titanium, copper, stainless steel and mixtures thereof, and are preferably applied to cell 20 by a suitable printing technology such as the ones listed above. Terminals 26 and 28 are used to electrically connect cell 20 to a load such as an electrically powered device. Terminals 26 and 28 may be located in any desired location of cell 20, may acquire any suitable shape and size and, depending on the specific application, terminals 26 and 28 may protrude from the surface of cell 20. Cell 20 may further include at least one externally located adhesive backing 29, to enable attaching cell 20 to various surfaces, and/or at least one externally located lamina protective layer 30 to physically protect all other layers.

    [0051] Yet another configuration is shown in Figures 3a-b. Two or more cells 10, as shown in Figure 3a, or cells 20, as shown in Figure 3b, may be electrically connected by a bi-polar connection to additively increase the electrical energy obtained of thus formed electrical power supplies 40 and 50, respectively. For this purpose two or more cells are adhered to one another in a head to tail orientation, as indicated in Figures 3a-b by layers 22, 14, 12, 16 and 24 arrangement, by a conductive double sided adhesive tape, or a conductive glue layer 42 applied for example by a suitable printing technology, enabling passage of electrons between adjacent cells. It is clear that electrical power supplies 40 and/or 50 may further include externally located adhesive backing(s) similar to surface 29 of Figure 2 and/or externally located lamina protective layer(s), similar to layer 30 of Figure 2. It is further clear that electrical power supplies 40 and 50 may include a negative and a positive terminal similar to terminals 26 and 28, respectively, of Figure 2.

    [0052] The present invention further includes a method of making a flexible thin layer open liquid state electrochemical cells similar to the cells described above, the method includes the steps of (a) wetting a porous substance an aqueous solution containing a deliquescent material, an electroactive soluble material and a watersoluble polymer; wetting may be achieved by either dipping or printing technologies; (b) applying onto one side of the porous substance a negative pole layer; and, (c) applying onto the second side of the porous substance a positive pole layer. The negative and positive pole layers include active insoluble powder substances mixed with the deliquescent material, electroactive soluble material and watersoluble polymer preferably of the same types as under (a), and are preferably applied using a suitable printing technology selected for example from the ones listed above.

    [0053] The method may further include adding to the cell additional layers and parts, such as but not limited to, externally located adhesive backing(s) and/or lamina protective layer(s), and negative and a positive terminals. Yet, the method may further include bi-polar joining of two or more cells, for example with a conductive double sided adhesive tape or a conductive glue layer applied for example by a suitable printing technology, to form a power supply with an increased power (e.g., substantially doubled, tripled, etc.). According to the present invention such bi-polar joining may be performed by joining together in a head to tail orientation two or more premanufactured cells, or alternatively, directly manufacturing two or more cells thus oriented, by applying suitable layer one after the other, preferably using a suitable printing technology as described above.

    [0054] The flexible thin layer open electrochemical cell of the present invention has a major advantage over prior art thin layer cells. Since it is an open cell it does not accumulate gases upon storage, yet it is maintained wet and intact by the use of a deliquescent material for keeping it wet at all times and a watersoluble polymer for obtaining the required viscosity for adhering the pole layers to the aqueous electrolyte layer.

    [0055] The flexible thin layer open electrochemical cell of the present invention has other qualities as follows. First, it has no outer rigid casting therefore it is thin light and flexible and may be manufactured in any size, shape, color and applied patterns, hence it is suitable for a variety of applications. Second, by using a suitable printing technology for its manufacturing its cost is reduced and therefore it may be disposed after use partly since large sheets can be produced and cut to any desired size following printing and partly since this technology is inherently cost effective. Third, it is preferably made of environmental and human friendly materials (it preferably contains no mercury or heavy metals). And finally, it may be manufactured self sticking via an adhesive backing.

    [0056] Reference in now made to the following examples, which together with the above descriptions, illustrate the invention.

    EXAMPLE 1



    [0057] A solution containing 120 mg of polyvinylalcohol (an aqueous soluble polymer) and 1680 mg of zinc-chloride (a deliquescent material and an electroactive soluble material) in 1.2 ml of water was prepared. This solution had a glue like viscous appearance. A 4.5 cm x 7 cm strip of a filter paper was thoroughly wetted with this solution by a printing or dipping technologies. A mixture of 300 mg zinc powder with the above solution was prepared and was printed on one side of the paper strip serving as the negative pole layer. On the other side printed was a mixture of 250 mg manganese-dioxide and 50 mg of a conductive carbon powder, together with the above solution, serving as the positive pole layer. When electrical contacts were made with both sides and were connected over a load an electrical current was measured. A current of 12 microampers per cm2 at a voltage of 1.7÷1.2 volts was easily maintained for five days continuously under room conditions.

    EXAMPLE 2



    [0058] An open cell was prepared as described under Example 1 above and was connected to a voltmeter. As shown in Figure 4, measurement of the voltage produced by the cell under room conditions revealed a pronounced voltage of 1.7÷ 1.2 sustained for nine successive days.

    EXAMPLE 3



    [0059] A saturated potassium-hydroxide solution is prepared and brought to the viscosity of a glue by mixing with a water soluble polymer. A porous substance (e.g., a filter paper) is thoroughly wetted with this solution and a mixture of the solution with nickel-oxide powder is pasted on one side of the porous substance to form a positive pole layer and, a similar mixture with cadmium powder is pasted on the other side of the porous substance to form a negative pole layer. By connecting a voltmeter to the two sides a voltage of 1.2 volts is measured and a high current is measured when the two layers are contacted over a load. The cell does not dry out in the open and can be recharged if so desired.

    EXAMPLE 4



    [0060] The same potassium-hydroxide solution as in Example 3 is prepared and a porous substance is wetted with it. A mixture of the solution with zinc powder is pasted on one side of the porous substance to form a negative pole layer and a similar mixture with silver-oxide powder containing some carbon powder if so desired is pasted on the other side of the porous substance to form a positive pole layer. By connecting a voltmeter to the two sides a voltage of 1.2 volts is measured and appreciable current is measured when the two layers are contacted over a load. The cell does not dry out in the open and can be recharged if so desired.

    EXAMPLE 5



    [0061] The same potassium-hydroxide solution as in Example 3 is prepared and a porous substance is wetted with it. A mixture of the solution with zinc powder is pasted on one side of the porous substance to form a negative pole layer and a similar mixture with manganese-dioxide powder containing some carbon powder if so desired is pasted on the other side of the porous substance to form a positive pole layer. By connecting a voltmeter to the two sides a voltage of 1.5 volts is measured and appreciable current is measured when the two layers are contacted over a load. The cell does not dry out in the open. Recharging thus formed cell may be troublesome.

    EXAMPLE 6



    [0062] The same potassium-hydroxide solution as in Example 3 is prepared and a porous substance is wetted with it. A mixture of the solution with nickel-oxide powder is pasted on one side of the porous substance to form a positive pole layer and a similar mixture with iron powder is pasted on the other side of the porous substance to form a negative pole layer. By connecting a voltmeter to the two sides a voltage of 0.9 volts is measured and a current can be measured when the two layers are contacted over a load. The cell does not dry out in the open and some recharged is possible if so desired.

    EXAMPLE 7



    [0063] A 30% sulfuric acid solution is prepared and brought to the viscosity of a glue by mixing with a water soluble polymer. A porous substance (e.g., a filter paper) is thoroughly wetted with this solution and a mixture of the solution with lead-oxide is pasted on both sides of the porous substance. Both sides are connected to a power supply and a voltage higher than 2 volts is applied by which the cell is charged. Charge and discharge cycles can be repeated without the cell drying out in the open.

    [0064] While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.


    Claims

    1. An open electrochemical cell comprising a first layer of insoluble negative pole, a second layer of insoluble positive pole and a third layer of wet electrolyte, said third layer being disposed between said first and second layers and including:

    (a) a deliquescent material for keeping the open cell wet at all times;

    (b) an electroactive soluble material for obtaining required ionic conductivity; and

    (c) a watersoluble polymer for obtaining a required viscocity for adhering said first and second layers to said third layer.


     
    2. A cell as in claim 1, wherein said electrolyte layer is engaged by a porous substance.
     
    3. A cell as in claim 2, wherein said porous substance is selected from the group consisting of a filter paper, a plastic membrane, a cellulose membrane and a cloth.
     
    4. A cell as in claim 1, wherein said first layer of insoluble negative pole includes manganese-dioxide powder and said second layer of insoluble positive pole includes zinc powder.
     
    5. A cell as in claim 4, wherein said first layer of insoluble negative pole further includes carbon powder.
     
    6. A cell as in claim 4, wherein said second layer of insoluble positive pole further includes carbon powder.
     
    7. A cell as in claim 4, wherein said electroactive soluble material is selected from the group consisting of zinc-chloride, zinc-bromide, zinc-fluoride and potassium-hydroxide.
     
    8. A cell as in claim 1, wherein said first layer of insoluble negative pole includes silver-oxide powder and said second layer of insoluble positive pole includes zinc powder.
     
    9. A cell as in claim 8, wherein said electroactive soluble material is potassium-hydroxide.
     
    10. A cell as in claim 1, wherein said first layer of insoluble negative pole includes cadmium powder and said second layer of insoluble positive pole includes nickel-oxide powder.
     
    11. A cell as in claim 10, wherein said electroactive soluble material is potassium-hydroxide.
     
    12. A cell as in claim 1, wherein said first layer of insoluble negative pole includes iron powder and said second layer of insoluble positive pole includes nickel-oxide powder.
     
    13. A cell as in claim 12, wherein said electroative soluble material is potassium-hydroxide.
     
    14. A cell as in claim 1, wherein said first layer of insoluble negative pole and said second layer of insoluble positive pole include lead-oxide powder, the cell is charged by voltage applied to said poles.
     
    15. A cell as in claim 14, wherein said electroactive soluble material is sulfuric-acid.
     
    16. A cell as in claim 1, wherein said deliquescent material and said electroactive soluble material are the same material.
     
    17. A cell as in claim 16, wherein said same material is selected from the group consisting of zinc-chloride, zinc-bromide, zinc-fluoride and potassium-hydroxide.
     
    18. A cell as in claim 1, wherein said deliquescent material is selected from the group consisting of calcium-chloride, calcium-bromide, potassium-biphosphate and potassium-acetate.
     
    19. A cell as in claim 1, wherein said watersoluble polymer is selected from the group consisting of polyvinylalcohol, poliacrylamide, polyacrylic acid, polyvinylpyrolidone, polyethylenoxide, agar, agarose, starch, hydroxyethylcellulose and combinations and copolymers thereof.
     
    20. A cell as in claim 1, wherein said watersoluble polymer and said deliquescent material are the same material.
     
    21. A cell as in claim 1, wherein said same material is selected from the group consisting of dextrane, dextranesulfate and combinations and copolymers thereof.
     
    22. A cell as in claim 1, further comprising terminals, each of said terminals being in electrical contact with one of said first and second pole layers.
     
    23. A cell as in claim 22, wherein said terminals are made of a metal.
     
    24. A cell as in claim 22, wherein said terminals are made of graphite.
     
    25. A cell as in claim 23, wherein said metal is selected from the group consisting of iron, nickel, titanium, copper, stainless steel and mixtures thereof, and said terminal are applied to the cell by a printing technology.
     
    26. A cell as in claim 1, further comprising at least one conductive layer improving the electronic conductivity of at least one of said first and second pole layers.
     
    27. A cell as in claim 26, wherein said conductive layer is selected from the group consisting of a graphite paper and carbon cloth.
     
    28. A cell as in claim 1, further comprising an external layer selected from the group consisting of an adhesive backing layer, a lamina protective layer and a combination of adhesive backing layer and a lamina protective layer.
     
    29. An electrical power supply comprising two cells as in claim 1 being connected in a head to tail orientation in a bipolar-connection.
     
    30. An electrical power supply as in claim 29, wherein said connection is by an adhesive selected from the group consisting of a conductive double sided adhesive tape and a conductive glue layer.
     
    31. An electrical power supply as in claim 30, wherein said conductive double sided adhesive tape and said conductive glue layer are applied by a printing technology.
     
    32. An open electrochemical cell comprising a first layer of insoluble negative pole, a second layer of insoluble positive pole and a third layer of wet electrolyte, said third layer being disposed between said first second layers and including:

    (a) a watersoluble polymer for obtaining a required viscosity far adhering said first and second layers to said third layer and for obtaining a required hygroscopicality for keeping the open cell wet at all times; and

    (b) an electroactive soluble material for obtaining a required ionic conductivity.


     
    33. A method of making an open electrochemical cell comprising the steps of:

    (a) wetting a porous substance having a first side and a second side with an aqueous solution containing a deliquescent material, an electroactive soluble material and a watersoluble polymer,

    (b) applying onto said first side a layer of negative pole; and

    (c) applying onto said second side a layer of positive pole.


     
    34. A method as in claim 33, wherein said wetting is by a dipping technology.
     
    35. A method as in claim 33, wherein said wetting is by a printing technology.
     
    36. A method as in claim 33, wherein said layers of negative and positive poles include active insoluble powder materials mixed with said deliquescent material, electroactive soluble material and watersoluble polymer.
     
    37. A method as in claim 36, wherein said application of said layers of negative and positive poles is by a printing technology.
     
    38. A cell as claimed in claim 1, wherein the electrolyte layer is engaged by a porous flexible substance.
     
    39. A cell as claimed in claim 1 or claim 32 wherein the cell is a flexible thin layer cell.
     
    40. A cell as claimed in claim 1 or claim 32 wherein the wet electrolyte comprises an aqueous electrolyte.
     


    Ansprüche

    1. Offene elektrochemische Zelle, umfassend eine erste Schicht unlöslichen negativen Pols, eine zweite Schicht unlöslichen positiven Pols und eine dritte Schicht nassen Elektrolyts, wobei die dritte Schicht zwischen der ersten und der zweiten Schicht angeordnet ist und umfasst :

    (a) ein zerfließendes Material, um die offene Zelle jederzeit nass zu halten ;

    (b) ein elektroaktives lösliches Material zum Erhalten der erforderlichen ionischen Leitfähigkeit ; und

    (c) ein wasserlösliches Polymer zum Erhalten einer erforderlichen Viskosität zum Anheften der ersten und zweiten Schicht an die dritte Schicht.


     
    2. Zelle nach Anspruch 1, wobei eine poröse Substanz an der Elektrolytschicht angreift.
     
    3. Zelle nach Anspruch 2, wobei die poröse Substanz aus der aus einem Filtrierpapier, einer Kunststoffmembran, einer Cellulosemembran und einem Tuch bestehenden Gruppe gewählt ist.
     
    4. Zelle nach Anspruch 1, wobei die erste Schicht unlöslichen negativen Pols Mangandioxidpulver umfasst und die zweite Schicht unlöslichen positiven Pols Zinkpulver umfasst.
     
    5. Zelle nach Anspruch 4, wobei die erste Schicht unlöslichen negativen Pols weiter Kohlenstoffpulver umfasst.
     
    6. Zelle nach Anspruch 4, wobei die zweite Schicht unlöslichen positiven Pols weiter Kohlenstoffpulver umfasst.
     
    7. Zelle nach Anspruch 4, wobei das elektroaktive lösliche Material aus der aus Zinkchlorid, Zinkbromid, Zinkfluorid und Kaliumhydroxid bestehenden Gruppe ausgewählt ist.
     
    8. Zelle nach Anspruch 1, wobei die erste Schicht unlöslichen negativen Pols Silberoxidpulver umfasst und die zweite Schicht unlöslichen positiven Pols Zinkpulver umfasst.
     
    9. Zelle nach Anspruch 8, wobei das elektroaktive lösliche Material Kaliumhydroxid ist.
     
    10. Zelle nach Anspruch 1, wobei die erste Schicht unlöslichen negativen Pols Kadmiumpulver umfasst und die zweite Schicht unlöslichen positiven Pols Nickeloxidpulver umfasst.
     
    11. Zelle nach Anspruch 10, wobei das elektroaktive lösliche Material Kaliumhydroxid ist.
     
    12. Zelle nach Anspruch 1, wobei die erste Schicht unlöslichen negativen Pols Eisenpulver umfasst und die zweite Schicht unlöslichen positiven Pols Nickeloxidpulver umfasst.
     
    13. Zelle nach Anspruch 12, wobei das elektroaktive lösliche Material Kaliumhydroxid ist.
     
    14. Zelle nach Anspruch 1, wobei die erste Schicht unlöslichen negativen Pols und die zweite Schicht unlöslichen positiven Pols Bleioxidpulver umfassen und die Zelle durch an diese Pole angelegte Spannung aufgeladen wird.
     
    15. Zelle nach Anspruch 14, wobei das elektroaktive lösliche Material Schwefelsäure ist.
     
    16. Zelle nach Anspruch 1, wobei das zerfließende Material und das elektroaktive lösliche Material das gleiche Material sind.
     
    17. Zelle nach Anspruch 16, wobei dieses gleiche Material aus der aus Zinkchlorid, Zinkbromid, Zinkfluorid und Kaliumhydroxid bestehenden Gruppe ausgewählt ist.
     
    18. Zelle nach Anspruch 1, wobei das zerfließende Material aus der aus Calciumchlorid, Calciumbromid, Kaliumdiphosphat und Kaliumacetat bestehenden Gruppe ausgewählt ist.
     
    19. Zelle nach Anspruch 1, wobei das wasserlösliche Polymer aus der aus Polyvinylalkohol, Polyacrylamid, Polyacrylsäure, Polyvinylpyrrolidon, Polyethylenoxid, Agar-Agar, Agarose, Stärke, Hydroxyethylcellulose und Kombinationen und Copolymeren davon bestehenden Gruppe ausgewählt ist.
     
    20. Zelle nach Anspruch 1, wobei das wasserlösliche Polymer und das zerfließende Material das gleiche Material sind.
     
    21. Zelle nach Anspruch 1, wobei dieses gleiche Material aus der aus Dextran, Dextransulfat und Kombinationen und Copolymeren davon bestehenden Gruppe ausgewählt ist.
     
    22. Zelle nach Anspruch 1, die weiter Anschlussklemmen umfasst, wobei jede der Anschlussklemmen in elektrischem Kontakt mit einer der ersten und der zweiten Polschicht ist.
     
    23. Zelle nach Anspruch 22, wobei die Anschlussklemmen aus Metall hergestellt sind.
     
    24. Zelle nach Anspruch 22, wobei die Anschlussklemmen aus Graphit hergestellt sind.
     
    25. Zelle nach Anspruch 23, wobei das Metall aus der aus Eisen, Nickel, Titan, Kupfer, Edelstahl und Mischungen davon bestehenden Gruppe gewählt ist und die Anschlussklemmen mittels einer Drucktechnologie an der Zelle angebracht werden.
     
    26. Zelle nach Anspruch 1, weiter mindestens eine leitende Schicht umfassend, die die elektronische Leitfähigkeit mindestens einer der ersten und der zweiten Polschicht verbessert.
     
    27. Zelle nach Anspruch 26, wobei die leitende Schicht aus der aus einem Graphitpapier und Kohlenstofftuch bestehenden Gruppe ausgewählt ist.
     
    28. Zelle nach Anspruch 1, weiter eine Außenschicht umfassend, die aus der aus einer Klebe-Rückschicht, einer Folien-Schutzschicht und einer Kombination aus Klebe-Rückschicht und einer Folien-Schutzschicht bestehenden Gruppe ausgewählt ist.
     
    29. Elektrische Stromversorgung, umfassend zwei Zellen nach Anspruch 1, die in einer Vorderende- an Hinterende-Orientierung in einer bipolaren Verbindung miteinander verbunden sind.
     
    30. Elektrische Stromversorgung nach Anspruch 29, wobei die Verbindung mittels eines Klebemittels ist, das aus der aus einem leitenden doppelseitigen Klebeband und einer leitenden Klebstoffschicht bestehenden Gruppe ausgewählt ist.
     
    31. Elektrische Stromversorgung nach Anspruch 30, wobei das leitende doppelseitige Klebeband und die leitende Klebstoffschicht mittels einer Drucktechnologie angebracht werden.
     
    32. Offene elektrochemische Zelle, umfassend eine erste Schicht unlöslichen negativen Pols, eine zweite Schicht unlöslichen positiven Pols und eine dritte Schicht nassen Elektrolyts, wobei die dritte Schicht zwischen der ersten und der zweiten Schicht angeordnet ist und umfasst :

    (a) ein wasserlösliches Polymer zum Erhalten einer erforderlichen Viskosität, um die erste und die zweite Schicht an der dritten Schicht anzuheften, und zum Erhalten eines erforderlichen hygroskopischen Verhaltens, um die offene Zelle jederzeit nass zu halten ; und

    (b) ein elektroaktives lösliches Material zum Erhalten einer erforderlichen ionischen Leitfähigkeit.


     
    33. Verfahren zur Herstellung einer offenen elektrochemischen Zelle, umfassend die Schritte des :

    (a) Benetzens einer porösen Substanz, die eine erste und eine zweite Seite aufweist, mit einer wässrigen Lösung, die ein zerfließendes Material, ein elektroaktives lösliches Material und ein wasserlösliches Polymer enthält ;

    (b) Anbringens einer Schicht negativen Pols an der ersten Seite ; und

    (c) Anbringens einer Schicht positiven Pols an der zweiten Seite.


     
    34. Verfahren nach Anspruch 33, wobei das Benetzen mittels einer Tauchtechnologie stattfindet.
     
    35. Verfahren nach Anspruch 33, wobei das Benetzen mittels einer Drucktechnologie stattfindet.
     
    36. Verfahren nach Anspruch 33, wobei die Schichten negativen und positiven Pols aktive unlösliche Pulvermaterialien, die mit dem zerfließenden Material, elektroaktiven löslichen Material und wasserlöslichen Polymer gemischt sind, umfassen.
     
    37. Verfahren nach Anspruch 36, wobei die Anbringung der Schichten negativen und positiven Pols mittels einer Drucktechnologie stattfindet.
     
    38. Zelle, wie in Anspruch 1 beansprucht, wobei eine poröse flexible Substanz an der Elektrolytschicht angreift.
     
    39. Zelle, wie in Anspruch 1 oder Anspruch 32 beansprucht, wobei die Zelle eine flexible Dünnschichtzelle ist.
     
    40. Zelle, wie in Anspruch 1 oder Anspruch 32 beansprucht, wobei der Nasselektrolyt einen wässrigen Elektrolyten umfasst.
     


    Revendications

    1. Pile électrochimique de configuration ouverte comprenant une première couche constituant un pôle négatif insoluble, une deuxième couche constituant un pôle positif insoluble et une troisième couche constituant un électrolyte liquide, ladite troisième couche étant disposée entre lesdites première et deuxième couches et englobant :

    (a) une matière déliquescente pour maintenir la pile de configuration ouverte liquide à tout moment ;

    (b) une matière soluble électroactive pour obtenir la conductivité ionique requise ; et

    (c) un polymère hydrosoluble pour obtenir une viscosité requise pour l'adhérence desdites première et deuxième couches à ladite troisième couche.


     
    2. Pile selon la revendication 1, dans laquelle ladite couche faisant office d'électrolyte est mise en contact avec une substance poreuse.
     
    3. Pile selon la revendication 2, dans laquelle ladite substance poreuse est choisie parmi le groupe constitué par un papier filtre, une membrane plastique, une membrane cellulosique et une étoffe.
     
    4. Pile selon la revendication 1, dans laquelle ladite première couche constituant un pôle négatif insoluble englobe de la poudre de dioxyde de manganèse et ladite deuxième couche constituant un pôle positif insoluble englobe de la poudre de zinc.
     
    5. Pile selon la revendication 4, dans laquelle ladite première couche constituant un pôle négatif insoluble englobe de la poudre de carbone.
     
    6. Pile selon la revendication 4, dans laquelle ladite deuxième couche constituant un pôle positif insoluble englobe en outre de la poudre de carbone.
     
    7. Pile selon la revendication 4, dans laquelle ladite matière électroactive soluble est choisie parmi le groupe constitué par le chlorure de zinc, le bromure de zinc, le fluorure de zinc et l'hydroxyde de potassium.
     
    8. Pile selon la revendication 1, dans laquelle ladite première couche constituant un pôle négatif insoluble englobe de la poudre d'oxyde d'argent et ladite deuxième couche constituant un pôle positif insoluble englobe de la poudre de zinc.
     
    9. Pile selon la revendication 8, dans laquelle ladite matière électroactive soluble est de l'hydroxyde de potassium.
     
    10. Pile selon la revendication 1, dans laquelle ladite première couche constituant un pôle négatif insoluble englobe de la poudre de cadmium et ladite deuxième couche constituant un pôle positif insoluble englobe de la poudre d'oxyde de nickel.
     
    11. Pile selon la revendication 10, dans laquelle ladite matière électroactive soluble est de l'hydroxyde de potassium.
     
    12. Pile selon la revendication 1, dans laquelle ladite première couche constituant un pôle négatif insoluble englobe de la poudre de fer et ladite deuxième couche constituant un pôle positif insoluble englobe de la poudre d'oxyde de nickel.
     
    13. Pile selon la revendication 12, dans laquelle ladite matière électroactive soluble est de l'hydroxyde de potassium.
     
    14. Pile selon la revendication 1, dans laquelle ladite première couche constituant un pôle négatif insoluble et ladite deuxième couche constituant un pôle positif insoluble englobent de la poudre d'oxyde de plomb, la pile étant chargée en appliquant une tension auxdites bornes.
     
    15. Pile selon la revendication 14, dans laquelle ladite matière électroactive soluble est de l'acide sulfurique.
     
    16. Pile selon la revendication 1, dans laquelle ladite matière déliquescente et ladite matière électroactive soluble représentent la même matière.
     
    17. Pile selon la revendication 16, dans laquelle ladite même matière est choisie parmi le groupe constitué par du chlorure de zinc, du bromure de zinc, du fluorure de zinc et de l'hydroxyde de potassium.
     
    18. Pile selon la revendication 1, dans laquelle ladite matière déliquescente est choisie parmi le groupe constitué par le chlorure de calcium, le bromure de calcium, le diphosphate de potassium et l'acétate de potassium.
     
    19. Pile selon la revendication 1, dans laquelle ledit polymère hydrosoluble est choisi parmi le groupe constitué par l'alcool polyvinylique, le polyacrylamide, l'acide polyacrylique, la polyvinylpyrrolidone, l'oxyde de polyéthylène, la gélose, l'agarose, l'amidon, l'hydroxyéthylcellulose ainsi que leurs combinaisons et leurs copolymères.
     
    20. Pile selon la revendication 1, dans laquelle ledit polymère hydrosoluble et ladite matière déliquescente représentent la même matière.
     
    21. Pile selon la revendication 1, dans laquelle ladite matière est choisie parmi le groupe constitué par le dextran, le sulfate de dextran ainsi que leurs combinaisons et leurs copolymères.
     
    22. Pile selon la revendication 1, comprenant en outre des bornes, chacune desdites bornes étant mise en contact électrique avec une desdites première et deuxième couche faisant office de pôles.
     
    23. Pile selon la revendication 22, dans laquelle lesdites bornes sont réalisées en métal.
     
    24. Pile selon la revendication 22, dans laquelle lesdites bornes sont réalisées en graphite.
     
    25. Pile selon la revendication 23, dans laquelle ledit métal est choisi parmi le groupe constitué par le fer, le nickel, le titane, le cuivre, l'acier inoxydable et leurs mélanges, lesdites bornes étant appliquées sur la pile via une technologie d'impression.
     
    26. Pile selon la revendication 1, comprenant en outre au moins une couche conductrice améliorant la conductivité électronique d'au moins une desdites première et deuxième couches faisant office de pôles.
     
    27. Pile selon la revendication 26, dans laquelle ladite couche conductrice est choisie parmi le groupe constitué par du papier graphité et de l'étoffe carbonée.
     
    28. Pile selon la revendication 1, comprenant en outre une couche externe choisie parmi le groupe constitué par une couche dorsale adhésive, une couche de protection stratifiée et une combinaison d'une couche dorsale adhésive et d'une couche de protection stratifiée.
     
    29. Alimentation électrique comprenant deux piles selon la revendication 1, reliées dans une orientation de tête à queue dans un raccord bipolaire.
     
    30. Alimentation électrique selon la revendication 22, dans laquelle ledit raccord est réalisé à l'aide d'un adhésif choisi parmi le groupe constitué par un ruban adhésif conducteur double face et une couche de colle conductrice.
     
    31. Alimentation électrique selon la revendication 30, dans laquelle ledit ruban adhésif conducteur double face et ladite couche de colle conductrice sont appliqués via une technologie d'impression.
     
    32. Pile électrochimique de configuration ouverte comprenant une première couche constituant un pôle négatif insoluble, une deuxième couche constituant un pôle positif insoluble et une troisième couche constituant un électrolyte liquide, ladite troisième couche étant disposée entre lesdites première et deuxième couches et englobant :

    (a) un polymère hydrosoluble pour obtenir une viscosité requise pour l'adhérence desdites première et deuxième couches à ladite troisième couche et pour obtenir une hygroscopicité requise pour maintenir la pile de configuration ouverte liquide à tout moment ; et

    (b) une matière soluble électroactive pour obtenir la conductivité ionique requise.


     
    33. Procédé de fabrication d'une pile électrochimique de configuration ouverte, comprenant les étapes consistant à :

    (a) humidifier une substance poreuse possédant un premier côté et un deuxième côté avec une solution aqueuse contenant une matière déliquescente, une matière électroactive soluble et un polymère hydrosoluble ;

    (b) appliquer sur ledit premier côté une couche constituant un pôle négatif ; et

    (c) appliquer sur ledit deuxième côté une couche constituant un pôle positif.


     
    34. Procédé selon la revendication 33, dans lequel ladite humidification est mise en oeuvre via une technologie d'immersion.
     
    35. Procédé selon la revendication 33, dans lequel ladite humidification est mise en oeuvre via une technologie d'impression.
     
    36. Procédé selon la revendication 33, dans lequel lesdites couches constituant un pôle négatif et un pôle positif englobent des matières actives pulvérulentes insolubles mélangées avec ladite matière déliquescente, ladite matière électroactive soluble et ledit polymère hydrosoluble.
     
    37. Procédé selon la revendication 36, dans lequel ladite application desdites couches constituant un pôle négatif et un pôle positif est mise en oeuvre via une technologie d'impression.
     
    38. Pile selon la revendication 1, dans laquelle la couche faisant office d'électrolyte est mise en contact avec une substance poreuse flexible.
     
    39. Pile selon la revendication 1 ou selon la revendication 32, dans laquelle la pile est une pile flexible en couche mince.
     
    40. Pile selon la revendication 1 ou selon la revendication 32, dans laquelle l'électrolyte liquide comprend un électrolyte aqueux.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description