EP3644455A1

EP3644455A1 - Electrical-terminal assembly with thermal monitoring

Info

Publication number: EP3644455A1
Application number: EP18202924.9A
Authority: EP
Inventors: Heiko BEHRENBECK; Paul G HALBACH; André OEKEN
Original assignee: Aptiv Technologies Ltd
Current assignee: Aptiv Technologies Ltd
Priority date: 2018-10-26
Filing date: 2018-10-26
Publication date: 2020-04-29
Anticipated expiration: 2038-10-26
Also published as: EP3644455B1

Abstract

A terminal-assembly (10) includes a wire-cable (12), an electrical-terminal (18), a housing (40), and a temperature-sensor (60). The wire-cable (12) has an insulation-layer and an exposed-end (16). The electrical-terminal (18) has a first-end (20) and a second-end (22). The first-end (20) is bonded with the exposed-end (16). The first-end (20) defines a terminal-head (26) terminating at a first-shoulder (30). The first-end (20) further defines a shaft (34) extending from the first-shoulder (30) and terminating at a second-shoulder (36). The housing (40) has a skirt (42) that defines a first-cavity (44) and a cap (46) that defines a second-cavity (48). The first-end (20) is disposed within the first-cavity (44). The first-cavity (44) is isolated from the second-cavity (48) by a partition (54). The skirt (42) extends from the partition (54) along the mating-axis (28) and defines a slot (56) configured to slideably engage the terminal-head (26). The skirt (42) has locking-features (58) configured to releasably lock around the electrical-terminal (18) when the terminal-head (26) is fully inserted into the slot (56). The temperature-sensor (60) is disposed within the second-cavity (48) and is configured to detect a temperature of the electrical-terminal (18).

Description

TECHNICAL FIELD

The present invention relates generally to an electrical terminal assembly that determines a temperature of the terminal-assembly.

BACKGROUND OF THE INVENTION

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

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.
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

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

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.
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.
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.
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).
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.
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.
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.
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.
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.
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.
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.
Figures 4a to 4b illustrate the assembled terminal-assembly 10 in a side view, and end view, and a top perspective view, respectively.

Claims

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).
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.
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).
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).
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).
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).
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).
The terminal-assembly (10) in accordance with claim 7, characterized in that the flange (88) overlays an exposed-edge (90) of the partition (54).
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).
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).