TECHNICAL FIELD
[0001] The present invention relates generally to an electrical terminal assembly that determines
a temperature of the terminal-assembly.
BACKGROUND OF THE INVENTION
[0002] The present invention relates more particularly to battery charging systems for electric
vehicles where a temperature of the electrical-terminals may exceed a specified value,
in a relatively short period of time, and cause damage to the charging system. A temperature
rise may occur before the temperature sensing device measures the peak temperature
due to a thermal latency of the electrical-terminals.
SUMMARY OF THE INVENTION
[0003] The present invention proposes to solve the above mentioned problem by providing
a terminal-assembly that includes a wire-cable, an electrical-terminal, a housing,
and a temperature-sensor. The wire-cable has an outer insulation-layer and an exposed-end
extending beyond the outer insulation-layer. The electrical-terminal has a first-end
and a second-end opposite the first-end. The first-end has a generally T-shape and
defines an attachment-zone bonded with the exposed-end. The first-end further defines
a terminal-head extending from the attachment-zone toward the second-end along a mating-axis
of the electrical-terminal and terminating at a first-shoulder, the terminal-head
having a generally cylindrical-shape defining a first-diameter. The first-end further
defines a shaft extending from the first-shoulder toward the second-end along the
mating-axis and terminating at a second-shoulder. The shaft has the generally cylindrical-shape
and defines a second-diameter. The second-diameter is less than the first-diameter.
The housing has a skirt that defines a first-cavity and a cap that defines a second-cavity
overlaying the first-cavity, with the first-end disposed within the first-cavity.
The cap defines an aperture aligned with a lateral-axis of the housing. The first-cavity
is electrically isolated from the second-cavity by a partition extending along the
lateral-axis. The partition overlays the exposed-end of the wire-cable. The skirt
extends from the partition toward the second-end of the electrical-terminal along
the mating-axis and defines a slot configured to slideably engage the terminal-head.
The skirt has locking-features configured to releasably lock around the shaft when
the terminal-head is fully inserted into the slot. The temperature-sensor is disposed
within the second-cavity and extends through the aperture. The temperature-sensor
is configured to detect a temperature of the electrical-terminal and is in direct
contact with a first-portion of the partition.
[0004] According to other advantageous features of the present invention:
- the partition has a thickness of between 1.0mm and 1.5mm.
- an adhesive is interposed between and in direct contact with both the exposed-end
of the wire-cable and the partition.
- the temperature-sensor is retained within the second-cavity with a locking-element
configured to releasably-lock to an outer-surface of the housing.
- the locking-element includes a platform extending into the aperture and overlaying
a second-portion of the partition, the platform defining a leading-edge in direct
contact with a trailing-edge of the temperature-sensor, thereby inhibiting a removal
of the temperature-sensor along the lateral-axis.
- a pair of opposed locking-tabs extend from a first-side and a second-side of the platform
along the lateral-axis, the pair of opposed locking-tabs engaging a corresponding
pair of locking-ramps extending from the outer-surface of the housing.
- the locking-element includes a flange that engages the housing at the aperture and
inhibits a movement of the locking-element along the lateral-axis.
- the flange overlays an exposed-edge of the partition.
- the housing includes a plurality of guide-beams extending from a back-wall of the
second-cavity along the lateral-axis, the plurality of guide-beams configured to inhibit
a movement of the temperature-sensor along the mating-axis and along a longitudinal-axis
orthogonal to both the mating-axis and the lateral-axis.
- the housing includes a stop extending from a back-wall of the second-cavity along
the lateral-axis, the stop configured to inhibit a movement of the temperature-sensor
along the lateral-axis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The present invention is now described by way of example with reference to the accompanying
drawings in which:
- figure 1 is an exploded view of a terminal-assembly according to a preferred embodiment
of the invention;
- figure 2a is a section view of the assembled terminal-assembly of figure 1;
- figure 2b is a magnified view of a portion of the terminal-assembly of figure 2a;
- figure 3 is a perspective view of a housing of the terminal-assembly of figure 1;
- figure 4a is a side view of the assembled terminal-assembly of figure 1;
- figure 4b is an end view of the assembled terminal-assembly of figure 1;
- figure 4c is a top perspective view of the assembled terminal-assembly of figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0006] Hereinafter, a terminal-assembly 10 for an electric vehicle battery charging system
according to an embodiment of the present invention will be described with reference
to the figures. Figure 1 is an exploded perspective view illustrating the overall
structure of the terminal-assembly 10. The terminal-assembly 10 includes a wire-cable
12 having an outer insulation-layer 14 and an exposed-end 16 extending beyond the
outer insulation-layer 14 (i.e., the outer insulation-layer 14 is stripped away exposing
the underlying wire). The wire-cable 12 is preferably formed of an alloy of copper
or aluminum and may include a conductive coating, such as tin. The wire-cable 12 may
be a solid wire-cable 12, or may be a stranded wire-cable 12, and in the example illustrated
in figure 1 is a stranded wire-cable 12.
[0007] The terminal-assembly 10 also includes an electrical-terminal 18 having a first-end
20 and a second-end 22 opposite the first-end 20. The electrical-terminal 18 is formed
of a conductive material, such as an alloy of copper or aluminum, and may include
the conductive coating tin. The first-end 20 has a generally T-shape and defines an
attachment-zone 24 bonded (e.g., welded) with the exposed-end 16 of the wire-cable
12. The weld may be any type of weld that creates a metallurgical bond, and in the
example illustrated in figure 1 is an ultrasonic weld.
[0008] The first-end 20 further defines a terminal-head 26 extending from the attachment-zone
24 toward the second-end 22 along a mating-axis 28 of the electrical-terminal 18 and
terminating at a first-shoulder 30. The terminal-head 26 has a generally cylindrical-shape
that defines a first-diameter 32. The terminal-head 26 also has opposed flattened
sides to aid in an assembly of the terminal-assembly 10, as will be described in more
detail below.
[0009] The first-end 20 further defines a shaft 34 extending from the first-shoulder 30
toward the second-end 22 along the mating-axis 28 and terminating at a second-shoulder
36. The shaft 34 also has the generally cylindrical-shape and defines a second-diameter
38 that is less than the first-diameter 32. In contrast to the terminal-head 26, the
shaft 34 has a continuous circular cross section (i.e., no flat sides).
[0010] The terminal-assembly 10 also includes a housing 40. The housing 40 has a skirt 42
that defines a first-cavity 44 and a cap 46 that defines a second-cavity 48 overlaying
the first-cavity 44, wherein the first-end 20 of the electrical-terminal 18 is disposed
within the first-cavity 44 (see figure 2a). The housing 40 is formed of a polymeric
dielectric material. The polymeric dielectric material may be any polymeric dielectric
material capable of electrically isolating portions of the electrical-terminal 18,
and is preferably a polyamide (NYLON). The polymeric dielectric material may include
a fiber fill (glass or other fiber) to increase a temperature resistance and a strength
of the housing 40.
[0011] The cap 46 defines an aperture 50 aligned with a lateral-axis 52 of the housing 40
configured to permit access to the second-cavity 48 along the lateral-axis 52. The
first-cavity 44 is electrically isolated from the second-cavity 48 by a partition
54 extending along the lateral-axis 52 and overlays the exposed-end 16 of the wire-cable
12 (see figure 2a). In other words, the partition 54 forms a "ceiling" to the first-cavity
44 and forms a "floor" to the second-cavity 48, thereby creating a boundary between
the first-cavity 44 and the second-cavity 48.
[0012] The skirt 42 extends from the partition 54 toward the second-end 22 of the electrical-terminal
18 along the mating-axis 28 and defines a slot 56 configured to slideably engage the
opposed flattened sides of the terminal-head 26. The slot 56 exists on both sides
of the skirt 42, as illustrated in figure 1. The skirt 42 has locking-features 58
configured to releasably lock around the shaft 34 when the terminal-head 26 is fully
inserted into the slot 56. That is, the skirt 42 is configured to flex outwardly as
the shaft 34 engages the locking-features 58 then returns to a neutral position locking
around the shaft 34 when the electrical-terminal 18 is fully seated in the first-cavity
44.
[0013] A temperature-sensor 60 is disposed within the second-cavity 48 extending through
the aperture 50 (see figure 2a). The temperature-sensor 60 may be any temperature-sensor
60 configured to detect a temperature of the electrical-terminal 18, and in the example
illustrated in figure 1 is a 2-wire negative temperature coefficient type (NTC-type)
temperature-sensor 60. The temperature-sensor 60 in direct contact with a first-portion
62 of the partition 54, as illustrated in figures 2a to 2b. The first-portion 62 of
the partition 54 is distal to the aperture 50.
[0014] Figures 2a to 2b are section views of the assembled terminal-assembly 10 viewed along
the mating-axis 28. The partition 54 has a thickness 64 of between 1.0mm and 1.5mm.
The thickness 64 in this range has the technical benefit of electrically isolating
the temperature-sensor 60 from the exposed-end 16 of the wire-cable 12, yet provides
sufficient response-time for the temperature-sensor 60 to detect the temperature rise
in the electrical-terminal 18. Preferably, an adhesive 66, such as an epoxy or other
adhesive 66 suitable for the operating temperatures of the terminal-assembly 10 (that
may be in excess of 125 degrees Celsius), is interposed between and in direct contact
with both the exposed-end 16 of the wire-cable 12 and the partition 54, as illustrated
in figure 2b. The adhesive 66 has the technical benefit of improving heat conduction
between the exposed-end 16 and the partition 54, and improves the response-time for
the temperature-sensor 60 to detect the temperature rise in the electrical-terminal
18. Preferably, any air-gap is eliminated by the presence of the adhesive 66.
[0015] Referring back to figure 1, the temperature-sensor 60 is retained within the second-cavity
48 with a locking-element 68 configured to releasably-lock to an outer-surface 70
of the housing 40. The locking-element 68 may be formed of the same polymeric material
as the housing 40. The locking-element 68 includes a platform 72 extending into the
aperture 50 and overlays a second-portion 74 of the partition 54, as illustrated in
figure 2b. The second-portion 74 of the partition 54 is proximal to the aperture 50.
The platform 72 defines a leading-edge 76 in direct contact with a trailing-edge 78
of the temperature-sensor 60, thereby inhibiting a removal of the temperature-sensor
60 along the lateral-axis 52 when the locking-element 68 is locked to the housing
40. A pair of opposed locking-tabs 80 extend from a first-side 82 and a second-side
84 of the platform 72 along the lateral-axis 52 and engage a corresponding pair of
locking-ramps 86 extending from the outer-surface 70 of the housing 40. Referring
again to figure 2b, the locking-element 68 includes a flange 88 that engages the housing
40 at the aperture 50 and overlays an exposed-edge 90 of the partition 54 that inhibits
a movement of the locking-element 68 along the lateral-axis 52.
[0016] Figure 3 is a perspective view of the housing 40 isolated from the terminal-assembly
10 and illustrates the internal surfaces of the first-cavity 44 and the second-cavity
48. The housing 40 includes a plurality of guide-beams 92 extending from a back-wall
94 of the second-cavity 48 along the lateral-axis 52. The plurality of guide-beams
92 are configured to inhibit a movement of the temperature-sensor 60 along the mating-axis
28, and movement along a longitudinal-axis 96 orthogonal to both the mating-axis 28
and the lateral-axis 52. Each of the plurality of guide-beams 92 include chamfers
to assist in the insertion of the temperature-sensor 60 into the second-cavity 48.
In addition to the plurality of guide-beams 92, the housing 40 also includes a stop
98 extending from the back-wall 94 along the lateral-axis 52 that is configured to
inhibit the movement of the temperature-sensor 60 along the lateral-axis 52. It will
be appreciated that the stop 98 of the housing 40 and the flange 88 of the locking-element
68 provide the technical benefit of maintaining a position of the temperature-sensor
60 within the second-cavity 48.
[0017] Figures 4a to 4b illustrate the assembled terminal-assembly 10 in a side view, and
end view, and a top perspective view, respectively.
1. A terminal-assembly (10), comprising:
a wire-cable (12) having an outer insulation-layer (14) and an exposed-end (16) extending
beyond the outer insulation-layer (14);
an electrical-terminal (18) having a first-end (20) and a second-end (22) opposite
the first-end (20);
the first-end (20) having a generally T-shape and defining an attachment-zone (24)
bonded with the exposed-end (16);
the first-end (20) further defining a terminal-head (26) extending from the attachment-zone
(24) toward the second-end (22) along a mating-axis (28) of the electrical-terminal
(18) and terminating at a first-shoulder (30), the terminal-head (26) having a generally
cylindrical-shape defining a first-diameter (32);
the first-end (20) further defining a shaft (34) extending from the first-shoulder
(30) toward the second-end (22) along the mating-axis (28) and terminating at a second-shoulder
(36), the shaft (34) having the generally cylindrical-shape and defining a second-diameter
(38), the second-diameter (38) less than the first-diameter (32);
a housing (40) having a skirt (42) that defines a first-cavity (44) and a cap (46)
that defines a second-cavity (48) overlaying the first-cavity (44), the first-end
(20) disposed within the first-cavity (44);
the cap (46) defining an aperture (50) aligned with a lateral-axis (52) of the housing
(40);
the first-cavity (44) electrically isolated from the second-cavity (48) by a partition
(54) extending along the lateral-axis (52), the partition (54) overlaying the exposed-end
(16) of the wire-cable (12);
the skirt (42) extending from the partition (54) toward the second-end (22) of the
electrical-terminal (18) along the mating-axis (28) and defining a slot (56) configured
to slideably engage the terminal-head (26);
the skirt (42) having locking-features (58) configured to releasably lock around the
shaft (34) when the terminal-head (26) is fully inserted into the slot (56);
characterized in that a temperature-sensor (60) is disposed within the second-cavity (48) extending through
the aperture (50), the temperature-sensor (60) configured to detect a temperature
of the electrical-terminal (18), the temperature-sensor (60) in direct contact with
a first-portion (62) of the partition (54).
2. The terminal-assembly (10) in accordance with claim 1, characterized in that the partition (54) has a thickness (64) of between 1.0mm and 1.5mm.
3. The terminal-assembly (10) in accordance with any one of the preceding claims, characterized in that an adhesive (66) is interposed between and in direct contact with both the exposed-end
(16) of the wire-cable (12) and the partition (54).
4. The terminal-assembly (10) in accordance with any one of the preceding claims, characterized in that the temperature-sensor (60) is retained within the second-cavity (48) with a locking-element
(68) configured to releasably-lock to an outer-surface (70) of the housing (40).
5. The terminal-assembly (10) in accordance with claim 4, characterized in that the locking-element (68) includes a platform (72) extending into the aperture (50)
and overlaying a second-portion (74) of the partition (54), the platform (72) defining
a leading-edge (76) in direct contact with a trailing-edge (78) of the temperature-sensor
(60), thereby inhibiting a removal of the temperature-sensor (60) along the lateral-axis
(52).
6. The terminal-assembly (10) in accordance with claim 5, characterized in that a pair of opposed locking-tabs (80) extend from a first-side (82) and a second-side
(84) of the platform (72) along the lateral-axis (52), the pair of opposed locking-tabs
(80) engaging a corresponding pair of locking-ramps (86) extending from the outer-surface
(70) of the housing (40).
7. The terminal-assembly (10) in accordance with any one of claims 4 to 6, characterized in that the locking-element (68) includes a flange (88) that engages the housing (40) at
the aperture (50) and inhibits a movement of the locking-element (68) along the lateral-axis
(52).
8. The terminal-assembly (10) in accordance with claim 7, characterized in that the flange (88) overlays an exposed-edge (90) of the partition (54).
9. The terminal-assembly (10) in accordance with any one of the preceding claims, characterized in that the housing (40) includes a plurality of guide-beams (92) extending from a back-wall
(94) of the second-cavity (48) along the lateral-axis (52), the plurality of guide-beams
(92) configured to inhibit a movement of the temperature-sensor (60) along the mating-axis
(28) and along a longitudinal-axis (96) orthogonal to both the mating-axis (28) and
the lateral-axis (52).
10. The terminal-assembly (10) in accordance with any one of the preceding claims, characterized in that the housing (40) includes a stop (98) extending from a back-wall (94) of the second-cavity
(48) along the lateral-axis (52), the stop (98) configured to inhibit a movement of
the temperature-sensor (60) along the lateral-axis (52).