(19)
(11)EP 2 860 810 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.10.2017 Bulletin 2017/40

(21)Application number: 14725951.9

(22)Date of filing:  06.02.2014
(51)Int. Cl.: 
H01M 10/04  (2006.01)
H01M 10/0585  (2010.01)
(86)International application number:
PCT/KR2014/001004
(87)International publication number:
WO 2014/123363 (14.08.2014 Gazette  2014/33)

(54)

STEPPED ELECTRODE ASSEMBLY COMPRISING STEP UNIT CELL

GESTUFTE ELEKTRODENANORDNUNG MIT STUFENEINHEITSZELLE

ASSEMBLAGE D'ÉLECTRODES ÉCHELONNÉ COMPRENANT UNE CELLULE UNITAIRE FORMANT UNE MARCHE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 08.02.2013 KR 20130014717

(43)Date of publication of application:
15.04.2015 Bulletin 2015/16

(73)Proprietor: LG Chem, Ltd.
Seoul 150-721 (KR)

(72)Inventors:
  • KWON, Sung-Jin
    Daejeon 305-380 (KR)
  • KIM, Dong-Myung
    Daejeon 305-380 (KR)
  • KIM, Ki-Woong
    Daejeon 305-380 (KR)
  • AHN, Soon-Ho
    Daejeon 305-380 (KR)

(74)Representative: Cabinet Plasseraud 
66, rue de la Chaussée d'Antin
75440 Paris Cedex 09
75440 Paris Cedex 09 (FR)


(56)References cited: : 
EP-A1- 2 750 239
EP-A1- 2 802 034
JP-A- 2010 062 081
KR-A- 20080 099 890
US-A1- 2001 005 561
US-A1- 2003 013 012
EP-A1- 2 750 241
JP-A- 2001 167 743
JP-A- 2010 097 730
KR-A- 20090 008 075
US-A1- 2002 122 975
US-A1- 2012 015 236
  
      
    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

    [Technical Field]



    [0001] The present disclosure relates to an electrode assembly having a stepped portion, and more particularly, to an electrode assembly having an increased degree of structural freedom in a thickness direction thereof.

    [Background Art]



    [0002] In the related art, an electrode assembly is assembled by stacking a plurality of C-type or A-type bi-cells, each of the C-type or A-type bi-cells including electrodes having the same polarity and an electrode having a different polarity and disposed between the electrodes of the same polarity.

    [0003] Referring to FIG. 1, an electrode assembly 1 having stepped portions may be assembled as follows: a first electrode stack is formed by stacking a plurality of bi-cells having the same area such as an A-type bi-cell 13 and a C-type bi-cell 11 shown in FIG. 2; and a second electrode stack in which bi-cells having equal areas smaller than the area of each electrode of the first electrode stack is disposed on the first electrode stack. In this manner, a stepped electrode assembly having an area decreasing in a vertical direction, such as the electrode assembly 1 shown in FIG. 1, may be assembled. Document US2003/013012 discloses an electrode assembly consisting of bi-cells with electrodes having the same area. Document US2001/005561 discloses a stepped electrode assembly.

    [Disclosure]


    [Technical Problem]



    [0004] New types of devices having various designs require batteries having new designs. Therefore, there is increasing demand for batteries having various designs.

    [0005] Therefore, an aspect of the present disclosure may provide an electrode assembly having an improved degree of structural freedom in the thickness direction thereof as compared with electrode assemblies assembled using bi-cells of the related art.

    [Technical Solution]



    [0006] According to an aspect of the present disclosure, a stepped electrode assembly has an improved degree of structural freedom in the thickness direction thereof. The stepped electrode assembly may include: a first electrode stack including at least one first unit cell, the first unit cell including at least one positive electrode and at least one negative electrode having the same area and being alternately stacked in a vertical direction with a separator disposed therebetween; and a second unit cell including at least one positive electrode and at least one negative electrode that are alternately stacked in the vertical direction with a separator disposed therebetween, the second unit cell disposed on a side of the first electrode stack with a separator disposed therebetween, wherein the second unit cell include a first area electrode having the same area as an electrode area of the first electrode stack and a second area electrode having an area different from the area of the first area electrode, wherein the second unit cell is a stepped unit cell including a stepped portion formed by an area difference between the first and second area electrodes.

    [0007] The first and second area electrodes of the stepped unit cell face each other, and one of the first and second area electrodes having a comparatively large area is a negative electrode. The stepped unit cell is an A-type bi-cell including positive electrodes on both sides thereof and a negative electrode disposed therebetween, or a C-type bi-cell including negative electrodes on both sides thereof and a positive electrode disposed therebetween.

    [0008] A second electrode stack including electrodes having the same area as the area of the second area electrode of the stepped unit cell may be disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and the second area electrode and an electrode of the second electrode stack facing the second area electrode may have different polarities.

    [0009] A second electrode stack including electrodes having equal areas different from the area of the second area electrode of the stepped unit cell may be disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and the second area electrode and an electrode of the second electrode stack facing the second area electrode may have different polarities. In this case, a larger of the second area electrode and the electrode of the second electrode stack facing the second area electrode may be a negative electrode.

    [0010] A second stepped unit cell may be disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and an electrode of the second stepped unit cell facing the second area electrode of the stepped unit cell may have the same area as the second area electrode but a polarity different from that of the second area electrode. In this case, a comparatively large electrode of the second stepped unit cell may be a negative electrode.

    [0011] A second stepped unit cell may be disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and an electrode of the second stepped unit cell facing the second area electrode of the stepped unit cell may have an area and polarity different from those of the second area electrode. In this case, a larger of the second area electrode and the electrode of the second unit cell facing the second area electrode may be a negative electrode, and a comparatively large electrode of the second stepped unit cell may be a negative electrode. Each of outermost electrodes disposed on both sides of the electrode assembly may be independently a negative electrode or a positive electrode. At least one of the outermost electrodes is a one-side-coated electrode.

    [0012] According to another aspect of the present disclosure, a secondary battery may include the electrode assembly. The electrode assembly may be disposed in a battery case. In this case, the battery case may be a pouch type case. In addition, the secondary battery may be a lithium ion secondary battery or a lithium ion polymer secondary battery.

    [0013] According to another aspect of the present disclosure, a battery pack may include at least two secondary batteries such as the above-described secondary battery.

    [0014] According to another aspect of the present disclosure, a device may include one or more secondary batteries such as the above-described secondary battery. The device may be a cellular phone, a portable computer, a smartphone, a smartpad, a net book, an LEV (light electronic vehicle), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, or a power storage device.

    [Advantageous Effects]



    [0015] According to the present disclosure, since the stepped electrode assembly is assembled using stepped bi-cells having stepped portions, the degree of structural freedom of the electrode assembly may be improved in the thickness direction thereof.

    [0016] Particularly, the degree of structural freedom of the electrode assembly may be markedly improved because it is not required to use an even number of bi-cells for disposing negative electrodes as a comparatively large electrode and outermost electrodes when assembling the electrode assembly.

    [0017] In addition, since the degree of structural freedom of the electrode assembly can be improved without using mono-cells, process errors caused by mono-cells bent when the mono-cells are gripped in a feeding process of unit cells may be prevented.

    [Description of Drawings]



    [0018] 

    FIG. 1 is a perspective view illustrating an electrode assembly having stepped portions.

    FIGS. 2A and 2B are schematic perspective views illustrating general bi-cells used to form an electrode assembly, FIG. 2A illustrating a C-type bi-cell, FIG. 2B illustrating an A-type bi-cell.

    FIG. 3 is a schematic cross-sectional view illustrating an electrode assembly assembled using bi-cells such as shown in FIGS. 2A and 2B.

    FIG. 4 is a schematic perspective view illustrating a mono-cell used to form an electrode assembly (not part of the present invention).

    FIG. 5 is a schematic cross-sectional view illustrating a comparative example of an electrode assembly not being part of the present invention having an improved degree of structural freedom in the thickness direction thereof, the electrode assembly being assembled using bi-cells and mono-cells such as shown in FIGS. 2A and 2B and FIG. 4.

    FIGS. 6A and 6B are schematic perspective views illustrating stepped bi-cells used to form an electrode assembly according to the present disclosure, FIG. 6A illustrating an A-type bi-cell, FIG. 6B illustrating a C-type bi-cell.

    FIGS. 7A and 7B are schematic cross-sectional views illustrating stepped bi-cells used to form an electrode assembly according to the present disclosure, FIG. 7A illustrating an A-type bi-cell, FIG. 7B illustrating a C-type bi-cell.

    FIG. 8 is a schematic cross-sectional view illustrating an electrode assembly assembled using stepped bi-cells according to the present disclosure.

    FIGS. 9A and 9B are schematic views illustrating bending of bi-cells and mono-cells when the bi-cells and the mono-cells are gripped in a feeding process, FIG. 9A illustrating bending of the bi-cells, FIG. 9B illustrating bending of the mono-cells.


    [Best Mode]



    [0019] Generally, an electrode assembly having a stepped portion is assembled by stacking a plurality of C-type or A-type bi-cells, each of the C-type or A-type bi-cell including electrodes of the same polarity and an electrode having a different polarity and disposed between the electrodes of the same polarity.

    [0020] For example, an electrode assembly 1 having stepped portions may be formed by assembling a first electrode stack 41 having a large size, a second electrode stack 43 having a medium size, and a third electrode stack 45 having a small size in such a manner that the first and second electrode stacks 41 and 43 face each other and the second and third electrode stacks 43 and 45 face each other as shown in FIG. 3. At interfaces of the first, second, and third electrode stacks 41, 43, and 45 at which stepped portions are formed, the larger electrode stacks 41 and 43 include negative electrodes 5 as interfacial electrodes, and the smaller electrode stacks 43 and 45 include positive electrodes 3 as interfacial electrodes. Therefore, electrodes having different polarities face each other at the interfaces of the first, second, and third electrode stacks 41, 43, and 45.

    [0021] In this case, as shown in FIG. 3, each of two or more electrode stacks (the second and third electrode stacks 43 and 45) to be disposed on the lowermost first electrode stack 41 may have an even number of bi-cells 11 and 13 (2 x n where n is an integer equal to or greater than 1). Therefore, there is a limitation when two or more electrode stacks (43 and 45) to be disposed on the lowermost first electrode stack 41 cannot be constituted by even numbers of bi-cells 11 and 13 due to the shape of a device in which the electrode assembly 1 will be used.

    [0022] The inventors have repeatedly conducted research to develop electrode assemblies having an improved degree of design freedom in the thickness direction thereof. As a result, the inventors found that if an electrode assembly is formed by assembling bi-cells having stepped portions, the thickness of the electrode assembly can be easily adjusted in a vertical direction. That is, the degree of structural freedom of the electrode assembly can be improved in the thickness direction thereof according to requirements of a device in which the electrode assembly will be used. The inventors have invented the present invention based on this knowledge.

    [0023] The present disclosure provides an electrode assembly including at least one unit cell in which at least one positive electrode and at least negative electrode are vertically stacked with a separator disposed therebetween. For example, as shown in FIG. 1, the present disclosure provides an electrode assembly having stopped portions and improved in the degree of freedom in the thickness direction thereof.

    [0024] In the present disclosure, the electrode assembly having a stepped portion may be formed by stacking unit cells. That is, the electrode assembly may be formed by stacking unit cells each including at least one negative electrode, at least one positive electrode, and a separator disposed between the negative and positive electrodes.

    [0025] In the present disclosure, the unit cells are not limited to a particular type. As shown in FIGS. 2A and 2B, examples of the unit cells may include: an A-type bi-cell 13 including positive electrodes 3 on both sides thereof and a negative electrode 5 disposed therebetween; and a C-type bi-cell 11 including negative electrodes 5 on both sides thereof and a positive electrodes 3 disposed therebetween. In addition, as shown in FIG. 4, examples of the unit cells, which are not contemplated in the present invention, may include a mono-cell 15 including a negative electrode 5, a positive electrode 3, and a separator 7 disposed therebetween.

    [0026] Bi-cells may be used as unit cells to reduce errors in a unit cell stacking process. That is, bi-cells each including three electrodes and two separators have a higher degree of stiffness than mono-cells each including a negative electrode, a positive electrode, with a separator disposed therebetween. As shown in FIGS. 9A and 9B, if mono-cells are used as unit cells to form an electrode assembly, the unit cells may be bent to cause process errors in a feeding process in which the unit cells are gripped and fed for stacking or arrangement. That is, if bi-cells having a high degree of stiffness are used as unit cells instead of mono-cells, process errors may be decreased.

    [0027] In the present disclosure, the electrode assembly is formed using the above-described unit cells. In the electrode assembly, positive and negative electrodes are alternately stacked in a vertical direction with separators disposed therebetween, and one or more stepped portions are formed on the electrode assembly. Such a stepped portion may be formed on two layers of at least two kinds of electrodes having different areas. For example, one or two stepped portions may be formed on two or three layers by disposing a stepped unit cell on a first electrode stack, wherein the stepped unit cell includes at least one first area electrode having a first area and at least one second area electrode disposed on the first area electrode and having a second area different from the first area.

    [0028] In the present disclosure, the stepped unit cell is a stepped bi-cell, and examples of the stepped bi-cell are shown in FIGS. 6A to 7B. FIGS. 6A and 6B are perspective views illustrating stepped bi-cells 21 and 23,

    [0029] and FIGS. 7A and 7B are cross-sectional views illustrating the stepped bi-cells 21 and 23. The stepped bi-cell 23 illustrated in FIGS. 7A and 7B is an A-type stepped bi-cell including positive electrodes 3 on both sides thereof and a negative electrode 5 disposed therebetween, and the stepped bi-cell 21 illustrated in FIGS. 6B and 7B is a C-type stepped bi-cell including negative electrodes 5 on both sides thereof and a positive electrode 3 disposed therebetween.

    [0030] In each of the stepped bi-cells 21 and 23 shown in FIGS. 6A to 7B, a stepped portion is formed by disposing a comparatively small positive electrode 3 on a comparatively large negative electrode 5. That is, the larger of two interfacial electrodes at which a stepped portion is formed may be a negative electrode. As described above, if a negative electrode is the larger of two interfacial electrodes, lithium may not precipitate from a positive electrode active material during charging and discharging operations of a battery, and thus the stability of the battery may not be deteriorated by the precipitation of lithium. The electrode assembly 1 shown in FIG. 5 may have an improved degree of structural freedom as compared with the electrode assembly 1 of FIG. 3 assembled by using the A-type and C-type bi-cells 13 and 11. However, according to an embodiment of the present disclosure, stepped bi-cells 31 and 33 such as the stepped bi-cells 21 and 23 shown in FIGS. 6A to 7B are used to form an electrode assembly 1 shown in FIG. 8. Referring to FIGS. 5 and 8, the electrode assembly 1 formed of the stepped bi-cells 31 and 33 according to the embodiment of the present disclosure has a small number of electrodes stacked in the thickness direction thereof as compared of the electrode assembly 1 formed of mono-cells. That is, the electrode assembly 1 of the embodiment of the present disclosure may have an improved degree of structural freedom.

    [0031] In the present disclosure, a stepped unit cell including a first area electrode having a comparatively large area and a second area electrode having a comparatively small area may be disposed on a first electrode stack in such a manner that the first or second area electrode faces the first electrode stack, and the first or second area electrode may have the same area as the area of an electrode of the first electrode stack facing the first or second area electrode. Alternatively, the first area electrode may be disposed to face an electrode stack constituted by electrodes having an area larger than the area of the first area electrode so as to form a stepped portion, and the second area electrode may be disposed to face an electrode stack constituted by electrodes having an area smaller than the area of the second area electrode so as to form a stepped portion.

    [0032] For example, a first stepped bi-cell may include positive and negative electrodes having a comparatively large area and a positive electrode having a comparatively small area, and the positive and negative electrodes having a comparatively large area may be disposed to face a first electrode stack having the same area as the positive and negative electrodes. In this way, two layers having areas decreasing in the height (vertical) direction thereof may be formed, and a single stepped portion may be formed on the two layers.

    [0033] Alternatively, the positive electrode of the first stepped bi-cell having a comparatively small area may be disposed on a second electrode stack having the same area of the positive electrode or may be disposed on a relatively large electrode of a second stepped bi-cell having the same area as the positive electrode may face. In this way, two layers having areas increasing in the height (vertical) direction thereof may be formed as an electrode assembly having a single stepped portion.

    [0034] For example, a comparatively large electrode of a stepped unit cell may be disposed to face a first electrode stack, and the comparatively large electrode may have an area smaller or larger than the electrode area of the first electrode stack. For example, an electrode of the stepped unit cell having an area smaller than the electrode area of the first electrode stack may be a comparatively large electrode of the stepped unit cell and may face the first electrode stack. Alternatively, an electrode stack having an area smaller than the area of a comparatively small electrode of the stepped unit cell may be disposed on the comparatively small electrode of the stepped unit cell. In this way, stepped portions may be formed between the first electrode stack and the stepped unit cell. That is, three layers having areas increasing or decreasing in the height (vertical) direction thereof may be formed as an electrode assembly having two stepped portions.

    [0035] As described above, a comparatively large electrode of the stepped unit cell located on an interface of the stepped unit cell forming a stepped portion may be a negative electrode. In addition, a comparatively large electrode disposed on an interface between the first electrode stack and the stepped unit cell may be a negative electrode.

    [0036] The first electrode stack and the stepped unit may be stacked in such a manner that mutually-facing electrodes of the first electrode stack and the stepped unit may have different polarities. If negative and positive electrodes are alternately arranged in an electrode assembly as described above, a battery reaction may occur throughout the electrode assembly, and thus the capacity of the electrode assembly (battery) may be increased.

    [0037] According to an embodiment of the present disclosure, a first stepped unit cell including a first area electrode having a comparatively large area and a second area electrode having a comparatively small area may be disposed on a first electrode stack, and a second electrode stack including electrodes having the same area may be disposed on the second area electrode of the first stepped unit with a separator disposed therebetween so as to form an electrode assembly. At this time, mutually-facing electrodes of the first stepped unit cell and the second electrode stack may have different polarities, and the area of each of the electrodes of the second electrode stack may be equal to or different from the area of the second area electrode. If the area of each of the electrodes of the second electrode stack is different from the area of the second area electrode of the first stepped unit cell, a stepped portion is formed at an interface between the first stepped unit cell and the second electrode stack, and the larger of the electrodes mutually facing each other at the interface may be a negative electrode.

    [0038] Then, the electrode assembly may have a first layer formed by the first electrode stack and the first area electrode (having a comparatively large area) of the first stepped unit cell (stepped bi-cell), and a second layer formed by the second area electrode (having a comparatively small area) of the first stepped unit cell and the second electrode stack. Alternatively, the electrode assembly may have a first layer formed by the first electrode stack and the first area electrode of the first stepped unit cell, a second layer formed by the second area electrode of the first stepped unit cell, and a third layer formed by the electrodes of the second electrode stack smaller than the second area electrode.

    [0039] Alternatively, in the electrode assembly of the embodiment of the present disclosure, a second stepped unit cell may be disposed on the second area electrode of the first stepped unit cell with a separator disposed therebetween. In this case, a comparatively large electrode of the second stepped unit cell may be a negative electrode, and mutually-facing electrodes of the first stepped unit cell and the second stepped unit cell may have different polarities. In addition, the area of an electrode of the second stepped unit cell facing the second area electrode of the first stepped unit cell may be equal to or different from the area of the second area electrode. For example, a stepped portion may be formed at an interface between the first stepped unit cell and the second stepped unit cell because the area of the second area electrode of the first stepped unit cell is different from the area of a first area electrode of the second stepped unit cell. In this case, the larger of the electrodes facing each other at the interface between the first and second stepped unit cells may also be a negative electrode.

    [0040] Then, the electrode assembly may have a first layer formed by the first electrode stack and the first area electrode of the first stepped unit cell, a second layer formed by the second area electrode of the first stepped unit cell and the first area electrode of the second stepped unit cell, and a third layer formed by the second area electrode of the second stepped unit cell. Alternatively, the electrode assembly may have a first layer formed by the first electrode stack and the first area electrode of the first stepped unit cell, a second layer formed by the second area electrode of the first stepped unit cell, a third layer formed by the first area electrode of the second stepped unit cell, and a fourth layer formed by the second area electrode of the second stepped unit cell.

    [0041] An exemplary electrode assembly 1 is schematically shown in FIG. 8 according to an embodiment of the present disclosure. Referring to FIG. 8, the electrode assembly 1 is formed by disposing a first stepped unit cell 31 on a first electrode stack 41, and disposing a second stepped unit cell 33 on the first stepped unit cell 31. The electrode assembly 1 has a width decreasing in the height direction thereof, and two stepped portions are formed on the electrode assembly 1. The first electrode stack 41 includes negative and positive electrodes 5 and 3 that are alternately stacked with separators 7 disposed therebetween.

    [0042] The first stepped unit cell 31 and the second stepped unit cell 33 are an A-type bi-cell 23 and a C-type bi-cell 21, respectively. In the first and second stepped unit cells 31 and 33, negative and positive electrodes are alternately stacked. In addition, the larger of mutually-facing electrodes of the first and second stepped unit cells 31 and 33 is a negative electrode, and the smaller of the mutually-facing electrodes is a positive electrode.

    [0043] The scope of the present disclosure are not limited to the above-described electrode assemblies. That is, first electrode stacks, stepped unit cells, second electrode stacks, and second unit cells may be variously combined to form various electrode assemblies.

    [0044] In the present disclosure, the outermost electrodes of an electrode assembly may be negative electrodes or positive electrodes, or may be a negative electrode and a positive electrode, respectively. In addition, the outermost electrodes of an electrode assembly are one-side-coated electrodes. The term "one-side-coated electrode" refers to an electrode in which only one side of a collector is coated with an electrode active material and the other side is not coated. In this case, sides of the outermost electrodes coated with an electrode active material may face with electrodes having a different polarity to contribute to charging and discharging reactions of a battery, and the other sides (non-coated portion) of the outermost electrodes not coated with the electrode active material may face the outside of the electrode assembly.

    [0045] Particularly, if a positive electrode is an outermost electrode of an electrode assembly, the positive electrode may be a one-side-coated electrode. Then, precipitation of lithium may be prevented during battery reactions, and thus the stability of a battery may be improved. In addition, if a negative electrode is an outermost electrode of an electrode assembly, the negative electrode may also be a one-side-coated electrode. In this case, the consumption of an electrode active material may be reduced to save costs, and the thickness of the electrode assembly may be reduced by the thickness of an electrode active material layer, thereby improving the degree of structural freedom of the electrode assembly in the thickness direction of the electrode assembly.

    [0046] Lithium ion secondary batteries or lithium ion polymer secondary batteries may be manufactured using electrode assemblies of the embodiments of the present disclosure. In this case, an electrode assembly may be disposed in a battery case, and the battery case may be a pouch or prism type battery case.

    [0047] In addition, a battery pack including at least two battery cells each including an electrode assembly of the present disclosure may be manufactured, and a device may include one or more of such battery cells. Examples of the device may be a cellular phone, a portable computer, a smartphone, a smartpad, a net book, a light electronic vehicle (LEV), an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.


    Claims

    1. A stepped electrode assembly consisting of bi-cells:

    each being either an A-type bi-cell consisting of, in a stacked manner, two positive electrodes, a negative electrode disposed between the positive electrodes and two separators, each disposed between one of the positive electrodes and the negative electrode; or a C-type bi-cell consisting of, in a stacked manner, two negative electrodes, a positive electrode disposed between the negative electrodes and two separators, each disposed between one of the negative electrodes and the positive electrode,
    wherein the bi-cells form together:

    a first electrode stack comprising at least one first bi-cell, said first bi-cell comprising at least one positive electrode and at least one negative electrode having the same area and being alternately stacked in a vertical direction with a separator disposed therebetween; and

    a second bi-cell, the second bi-cell disposed on a side of the first electrode stack with a separator disposed therebetween,

    wherein the second bi-cell comprises a first area electrode having the same area as an electrode area of the first electrode stack and a second area electrode having an area different from the area of the first area electrode,

    wherein the second bi-cell is a stepped bi-cell comprising a stepped portion formed by an area difference between the first and second area electrodes, the larger of the two interfacial electrodes at which the stepped portion is formed being a negative electrode, and

    characterized in that at least one of the outermost electrodes of the electrode assembly is a one-side-coated electrode.


     
    2. The electrode assembly of claim 1, wherein the first and second area electrodes of the stepped bi-cell face each other, and one of the first and second area electrodes having a comparatively large area is a negative electrode.
     
    3. The electrode assembly of claim 2, wherein a second electrode stack comprising electrodes having the same area as the area of the second area electrode of the stepped bi-cell is disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and the second area electrode and an electrode of the second electrode stack facing the second area electrode have different polarities.
     
    4. The electrode assembly of claim 2, wherein a second electrode stack comprising electrodes having equal areas different from the area of the second area electrode of the stepped bi-cell is disposed on the second area electrode of the stepped unit cell with a separator disposed therebetween, and the second area electrode and an electrode of the second electrode stack facing the second area electrode have different polarities.
     
    5. The electrode assembly of claim 4, wherein a larger of the second area electrode and the electrode of the second electrode stack facing the second area electrode is a negative electrode.
     
    6. The electrode assembly of claim 2, wherein a second stepped unit cell is disposed on the second area electrode of the stepped bi-cell with a separator disposed therebetween, and an electrode of the second stepped unit cell facing the second area electrode of the stepped bi-cell has the same area as the second area electrode but a polarity different from that of the second area electrode.
     
    7. The electrode assembly of claim 6, wherein a comparatively large electrode of the second stepped unit cell is a negative electrode.
     
    8. The electrode assembly of claim 2, wherein a second stepped unit cell is disposed on the second area electrode of the stepped bi-cell with a separator disposed therebetween, and an electrode of the second stepped unit cell facing the second area electrode of the stepped unit cell has an area and polarity different from those of the second area electrode.
     
    9. The electrode assembly of claim 8, wherein a larger of the second area electrode and the electrode of the second unit cell facing the second area electrode is a negative electrode, and a comparatively large electrode of the second stepped unit cell is a negative electrode.
     
    10. The electrode assembly of any one of claims 1 to 9, wherein each of outermost electrodes disposed on both sides of the electrode assembly is independently a negative electrode or a positive electrode.
     
    11. A secondary battery comprising the electrode assembly of any one of claims 1 to 10.
     


    Ansprüche

    1. Gestufte Elektrodenanordnung, bestehend aus Bi-Zellen:

    wobei jede entweder eine A-Typ-Bi-Zelle ist, welche in einer gestapelten Weise aus zwei positiven Elektroden, einer zwischen den positiven Elektroden angeordneten negativen Elektrode und zwei Separatoren, von welchen jeder zwischen einer der positiven Elektroden und der negativen Elektrode angeordnet ist, besteht; oder eine C-Typ-Bi-Zelle ist, welche in einer gestapelten Weise aus zwei negativen Elektroden, einer zwischen den negativen Elektroden angeordneten positiven Elektrode und zwei Separatoren, von welchen jeder zwischen einer der negativen Elektroden und der positiven Elektrode angeordnet ist, besteht,
    wobei die Bi-Zellen zusammen ausbilden:

    einen ersten Elektrodenstapel, welcher wenigstens eine erste Bi-Zelle umfasst, wobei die erste Bi-Zelle wenigstens eine positive Elektrode und wenigstens eine negative Elektrode umfasst, welche die gleiche Fläche aufweisen und alternierend in einer vertikalen Richtung mit einem dazwischen angeordneten Separator gestapelt sind; und

    eine zweite Bi-Zelle, wobei die zweite Bi-Zelle an einer Seite des ersten Elektrodenstapels mit einem dazwischen angeordneten Separator angeordnet ist,
    wobei die zweite Bi-Zelle eine erste Flächenelektrode, welche die gleiche Fläche wie eine Elektrodenfläche des ersten Elektrodenstapels aufweist, und eine zweite Flächenelektrode umfasst, welche eine sich von der Fläche der ersten Flächenelektrode unterscheidende Fläche aufweist,

    wobei die zweite Bi-Zelle eine gestufte Bi-Zelle ist, welche einen gestuften Abschnitt umfasst, welcher durch einen Flächenunterschied zwischen der ersten und der zweiten Flächenelektrode ausgebildet ist, wobei die größere der zwei Grenzflächenelektroden, an welcher der gestufte Abschnitt ausgebildet ist, eine negative Elektrode ist, und

    dadurch gekennzeichnet, dass wenigstens eine der äußersten Elektroden der Elektrodenanordnung eine einseitig beschichtete Elektrode ist.


     
    2. Elektrodenanordnung nach Anspruch 1, wobei die erste und die zweite Flächenelektrode der gestuften Bi-Zelle einander zugewandt sind und eine aus der ersten und der zweiten Flächenelektrode, welche eine vergleichsweise große Fläche aufweist, eine negative Elektrode ist.
     
    3. Elektrodenanordnung nach Anspruch 2, wobei ein zweiter Elektrodenstapel, welcher Elektroden mit der gleichen Fläche wie die Fläche der zweiten Flächenelektrode der gestuften Bi-Zelle umfasst, an der zweiten Flächenelektrode der gestuften Einheitszelle mit einem dazwischen angeordneten Separator angeordnet ist, und wobei die zweite Flächenelektrode und eine Elektrode des zweiten Elektrodenstapels, welche der zweiten Flächenelektrode zugewandt ist, unterschiedliche Polaritäten aufweisen.
     
    4. Elektrodenanordnung nach Anspruch 2, wobei ein zweiter Elektrodenstapel, welcher Elektroden mit gleichen, sich von der Fläche der zweiten Flächenelektrode der gestuften Bi-Zelle unterscheidenden Flächen umfasst, an der zweiten Flächenelektrode der gestuften Einheitszelle mit einem dazwischen angeordneten Separator angeordnet ist, und wobei die zweite Flächenelektrode und eine Elektrode des zweiten Elektrodenstapels, welche der zweiten Flächenelektrode zugewandt ist, unterschiedliche Polaritäten aufweisen.
     
    5. Elektrodenanordnung nach Anspruch 4, wobei eine größere der zweiten Flächenelektrode und der Elektrode des zweiten Elektrodenstapels, welche der zweiten Flächenelektrode zugewandt ist, eine negative Elektrode ist.
     
    6. Elektrodenanordnung nach Anspruch 2, wobei eine zweite gestufte Einheitszelle an der zweiten Flächenelektrode der gestuften Bi-Zelle mit einem dazwischen angeordneten Separator angeordnet ist, und eine Elektrode der zweiten gestuften Einheitszelle, welche der zweiten Flächenelektrode der gestuften Bi-Zelle zugewandt ist, die gleiche Fläche wie die zweite Flächenelektrode, jedoch eine sich von der der zweiten Flächenelektrode unterscheidende Polarität aufweist.
     
    7. Elektrodenanordnung nach Anspruch 6, wobei eine vergleichsweise große Elektrode der zweiten gestuften Einheitszelle eine negative Elektrode ist.
     
    8. Elektrodenanordnung nach Anspruch 2, wobei eine zweite gestufte Einheitszelle an der zweiten Flächenelektrode der gestuften Bi-Zelle mit einem dazwischen angeordneten Separator angeordnet ist, und eine Elektrode der zweiten gestuften Einheitszelle, welche der zweiten Flächenelektrode der gestuften Einheitszelle zugewandt ist, eine Fläche und eine Polarität aufweist, die sich von denjenigen der zweiten Flächenelektrode unterscheiden.
     
    9. Elektrodenanordnung nach Anspruch 8, wobei eine größere der zweiten Flächenelektrode und der Elektrode der zweiten Einheitszelle, welche der zweiten Flächenelektrode zugewandt ist, eine negative Elektrode ist, und eine vergleichsweise große Elektrode der zweiten gestuften Einheitszelle eine negative Elektrode ist.
     
    10. Elektrodenanordnung nach einem der Ansprüche 1 bis 9, wobei jede von äußersten Elektroden, welche an beiden Seiten der Elektrodenanordnung angeordnet sind, unabhängig eine negative Elektrode oder eine positive Elektrode ist.
     
    11. Sekundärbatterie, welche die Elektrodenanordnung nach einem der Ansprüche 1 bis 10 umfasst.
     


    Revendications

    1. Ensemble d'électrodes échelonné, constitué de bi-cellules :

    chacune étant une bi-cellule de type A constituée, de manière empilée, de deux électrodes positives, d'une électrode négative disposée entre les électrodes positives et de deux séparateurs, chacun disposé entre l'une des électrodes positives et l'électrode négative ; ou une bi-cellule de type C constituée, de manière empilée, de deux électrodes négatives, d'une électrode positive disposée entre les électrodes négatives et de deux séparateurs, chacun disposé entre l'une des électrodes négatives et l'électrode positive,
    dans lequel les bi-cellules forment ensemble :

    un premier empilement d'électrodes comprenant au moins une première bi-cellule, ladite première bi-cellule comprenant au moins une électrode positive et au moins une électrode négative possédant la même superficie et étant empilées tour à tour dans une direction verticale avec un séparateur disposé entre celles-ci ; et

    une seconde bi-cellule, la seconde bi-cellule étant disposée sur une face du premier empilement d'électrodes avec un séparateur disposé entre ceux-ci,

    dans lequel la seconde bi-cellule comprend une électrode de première superficie possédant la même superficie qu'une superficie d'électrode du premier empilement d'électrodes et une électrode de seconde superficie possédant une superficie différente de la superficie de l'électrode de première superficie,
    dans lequel la seconde bi-cellule est une bi-cellule échelonnée comprenant une portion échelonnée formée par une différence de superficie entre les électrodes de première et de seconde superficies, la plus grande des deux électrodes d'interface, au niveau desquelles la portion échelonnée est formée, étant une électrode négative, et
    caractérisé en ce qu'au moins l'une des électrodes les plus extérieures de l'ensemble d'électrodes est une électrode enduite sur une face.


     
    2. Ensemble d'électrodes selon la revendication 1, dans lequel les électrodes de première et de seconde superficies de la bi-cellule échelonnée se font face, et l'une des électrodes de première et de seconde superficies possédant une superficie comparativement grande est une électrode négative.
     
    3. Ensemble d'électrodes selon la revendication 2, dans lequel un second empilement d'électrodes comprenant des électrodes possédant la même superficie que la superficie de l'électrode de seconde superficie de la bi-cellule échelonnée est disposé sur l'électrode de seconde superficie de la cellule unitaire échelonnée avec un séparateur disposé entre ceux-ci, et l'électrode de seconde superficie et une électrode du second empilement d'électrodes faisant face à l'électrode de seconde superficie possèdent des polarités différentes.
     
    4. Ensemble d'électrodes selon la revendication 2, dans lequel un second empilement d'électrodes comprenant des électrodes possédant des superficies égales différentes de la superficie de l'électrode de seconde superficie de la bi-cellule échelonnée est disposé sur l'électrode de seconde superficie de la cellule unitaire échelonnée avec un séparateur disposé entre ceux-ci, et l'électrode de seconde superficie et une électrode du second empilement d'électrodes faisant face à l'électrode de seconde superficie possèdent des polarités différentes.
     
    5. Ensemble d'électrodes selon la revendication 4, dans lequel une plus grande parmi l'électrode de seconde superficie et l'électrode du second empilement d'électrodes faisant face à l'électrode de seconde superficie est une électrode négative.
     
    6. Ensemble d'électrodes selon la revendication 2, dans lequel une seconde cellule unitaire échelonnée est disposée sur l'électrode de seconde superficie de la bi-cellule échelonnée avec un séparateur disposé entre celles-ci, et une électrode de la seconde cellule unitaire échelonnée faisant face à l'électrode de seconde superficie de la bi-cellule échelonnée possède la même superficie que l'électrode de seconde superficie mais une polarité différente de celle de l'électrode de seconde superficie.
     
    7. Ensemble d'électrodes selon la revendication 6, dans lequel une électrode comparativement grande de la seconde cellule unitaire échelonnée est une électrode négative.
     
    8. Ensemble d'électrodes selon la revendication 2, dans lequel une seconde cellule unitaire échelonnée est disposée sur l'électrode de seconde superficie de la bi-cellule échelonnée avec un séparateur disposé entre celles-ci, et une électrode de la seconde cellule unitaire échelonnée faisant face à l'électrode de seconde superficie de la cellule unitaire échelonnée possède une superficie et une polarité différentes de celles de l'électrode de seconde superficie.
     
    9. Ensemble d'électrodes selon la revendication 8, dans lequel une plus grande parmi l'électrode de seconde superficie et l'électrode de la seconde unité cellule faisant face à l'électrode de seconde superficie est une électrode négative, et une électrode comparativement grande de la seconde cellule unitaire échelonnée est une électrode négative.
     
    10. Ensemble d'électrodes selon l'une quelconque des revendications 1 à 9, dans lequel chacune des électrodes les plus extérieures disposées sur les deux faces de l'ensemble d'électrodes est indépendamment une électrode négative ou une électrode positive.
     
    11. Batterie secondaire comprenant l'ensemble d'électrodes de selon l'une quelconque des revendications 1 à 10.
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description