JP7680994B2 - Battery Module - Google Patents

Description

This technology relates to battery modules.

For example, as shown in Patent Documents 1 and 2, a conventional practice is to connect a bus bar and a conductor, or bus bars together, by clamping them with a clip member.

Patent document 3 also discloses an open/close test connection terminal for connecting lead wires to a switchboard terminal, etc., when testing and measuring the voltage and current of the main circuit of a switchboard, distribution board, etc.

JP 2021-51999 A JP 2014-154246 A JP 2009-176662 A

In the structure for connecting the voltage detection line to the bus bar, a screw fastening structure and a welded structure are used. However, when a screw fastening structure or a welded structure is used, the manufacturing cost increases. For example, the resistance value required for the connection structure between the voltage detection line and the bus bar is on the order of mΩ, but when a welded structure is used, the resistance value is on the order of μΩ, which may result in overdesign.

The purpose of this technology is to provide a battery module that prevents increases in manufacturing costs due to overdesign.

This technology provides the following battery modules:

[1] A battery module including: a plurality of battery cells arranged in a first direction, each having a housing and an electrode terminal provided on the housing; a plate-shaped bus bar connecting the electrode terminals of the plurality of battery cells; a voltage detection wire for detecting the voltage of the bus bar; and a conductive clip member electrically connected to the voltage detection wire and biased to clamp at least a portion of the bus bar.

[2] The battery module described in [1], in which the voltage detection line is crimped and connected to the clip member from the first direction.

[3] The battery module described in [1] or [2], in which the clip member includes a U-shaped portion that clamps the bus bar.

[4] A battery cell according to [3], in which the U-shaped portion is fitted to the busbar from a second direction perpendicular to the first direction.

[5] A battery module according to any one of [1] to [4], wherein the busbar has a groove that receives a portion of the clip member.

[6] A battery module according to [5], in which the grooves are formed on both sides of the busbar.

[7] A battery module according to any one of [1] to [6], further comprising a wall portion surrounding at least a portion of the bus bar and the clip member.

[8] A battery module according to [7], in which the wall portion is made of insulating resin.

[9] A battery module according to any one of [1] to [8], in which the housings of the multiple battery cells have a rectangular shape.

[10] A battery module according to any one of [1] to [9], wherein the plurality of battery cells are lithium ion battery cells.

This technology can avoid the increase in manufacturing costs of battery modules due to over-design. Furthermore, since large currents do not flow through the voltage detection wire, the required resistance value specifications can be met without necessarily adopting a welded structure.

FIG. 2 is a diagram showing a basic configuration of a battery module. FIG. 2 is a perspective view showing a battery cell. FIG. 4 is a diagram showing the arrangement of bus bars in a battery module. FIG. 4 is an exploded perspective view showing a connection structure between a bus bar and a voltage detection line in a battery module. 4 is a perspective view showing a connection structure between a bus bar and a voltage detection line in a battery module. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. 13 is a cross-sectional view showing a modified example of the connection structure between the bus bar and the voltage detection line.

The following describes an embodiment of the present technology. Note that the same or corresponding parts are given the same reference symbols, and their descriptions may not be repeated.

In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. In addition, in the embodiments described below, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

In this specification, the words "comprise," "include," and "have" are open-ended. In other words, when a certain configuration is included, other configurations may or may not be included.

In addition, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate the relative positional relationship in one state, and the relative positional relationship can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

In this specification, "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium ion batteries. In this specification, "electrode" may collectively refer to positive electrodes and negative electrodes. Also, "electrode plate" may collectively refer to positive electrode plates and negative electrode plates.

In this specification, a "battery cell" can be installed in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), an electric vehicle (BEV), etc. However, the use of a "battery cell" is not limited to being installed in a vehicle.

Figure 1 shows the basic configuration of a battery module 1. As shown in Figure 1, the battery module 1 includes a battery cell 100, an end plate 200, and a restraining member 300.

The multiple battery cells 100 are arranged in a line in the Y-axis direction (first direction). This forms a stack of battery cells 100. The battery cells 100 include electrode terminals 110. Separators (not shown) are interposed between the multiple battery cells 100. The multiple battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 and are restrained between the two end plates 200.

The end plates 200 are disposed at both ends of the battery module 1 in the Y-axis direction. The end plates 200 are fixed to a base such as a case that houses the battery module 1. The restraining member 300 connects the two end plates 200 to each other.

The restraining member 300 is fixed to the end plate 200 while a compressive force in the Y-axis direction is applied to the stack of multiple battery cells 100 and end plates 200, and then the compressive force is released, so that a tensile force acts on the restraining member 300 connecting the two end plates 200. In reaction to this, the restraining member 300 presses the two end plates 200 in a direction that brings them closer to each other.

Figure 2 is a perspective view showing the battery cell 100. As shown in Figure 2, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110 and a housing 120 (external can). In other words, the battery cell 100 is a rectangular secondary battery cell.

The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 aligned along the X-axis direction (second direction) perpendicular to the Y-axis direction (first direction). The positive electrode terminal 111 and the negative electrode terminal 112 are spaced apart from each other in the X-axis direction.

The housing 120 has a rectangular parallelepiped shape and forms the external appearance of the battery cell 100. The housing 120 includes a case body 120A that contains an electrode body and an electrolyte (not shown), and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125. The housing 120 is provided with a gas exhaust valve 126.

The upper surface 121 is a plane perpendicular to the Z-axis direction (third direction) that is perpendicular to the Y-axis direction and the X-axis direction. The electrode terminal 110 is disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

Each of the first side surface 123 and the second side surface 124 consists of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape with the X-axis direction being the long side direction and the Z-axis direction being the short side direction when viewed in the Y-axis direction.

The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the adjacent battery cells 100, 100 in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

The gas exhaust valve 126 is provided on the top surface 121. When the temperature of the battery cell 100 rises (thermal runaway) and the internal pressure of the housing 120 exceeds a predetermined value due to gas generated inside the housing 120, the gas exhaust valve 126 exhausts the gas to the outside of the housing 120.

Figure 3 is a diagram showing the arrangement of bus bars 400 in a battery module 1. In the example of Figure 3, the positive electrode terminals 111 and negative electrode terminals 112 of adjacent battery cells 100 are electrically connected by bus bars 400, and multiple battery cells 100 are electrically connected in series.

That is, the battery module 1 includes a plurality of battery cells 100, each having an electrode terminal 110, arranged along a predetermined direction, and a bus bar 400 that connects the electrode terminals 110 of the plurality of battery cells 100 together. The bus bar 400 is a plate-shaped member having a thickness of, for example, about 0.8 mm to 1.5 mm. The bus bar 400 is made of, for example, aluminum, copper, or the like.

Figure 4 is an exploded perspective view showing the connection structure between the bus bar 400 and the voltage detection line 600. Figure 5 is a perspective view showing the state in which the bus bar 400 and the voltage detection line 600 shown in Figure 4 are connected, and Figure 6 is a cross-sectional view taken along line VI-VI in Figure 5. Figure 7 is a cross-sectional view showing the connection structure between the bus bar 400 and the voltage detection line 600 according to a modified example.

As shown in Figures 4 to 7, the clip member 500 made of a conductive material includes a U-shaped portion that clamps the bus bar 400. The clip member 500 is made of, for example, nickel-plated brass. The clip member 500 is fitted to the bus bar 400 from the X-axis direction. The clip member 500 is biased so as to clamp the bus bar 400.

To ensure that each battery cell 100 included in the battery module 1 is performing as expected, it is common to measure the potential of each bus bar 400. A voltage detection line 600 is provided to measure the voltage of each bus bar 400.

The voltage detection wire 600 can be a commonly used copper wire. The voltage detection wire 600 is connected to the clip member 500 from the Y-axis direction (for example, by tab crimping). This electrically connects the clip member 500 and the voltage detection wire 600.

As shown in FIG. 5, the bus bar 400 is provided on a bus bar module including a plate 700 and a wall portion 800. The wall portion 800 is provided so as to surround at least a portion of the bus bar 400 and the clip member 500. The plate 700 and the wall portion 800 are made of, for example, an insulating resin.

The bus bar 400 is placed in an area of the plate 700 surrounded by the wall portion 800. The plate 700 is provided above a plurality of battery cells 100 arranged in the Y-axis direction. The wall portion 800 is also adjacent to the clip member 500 connected to the bus bar 400. This can prevent the clip member 500 from unintentionally coming off the bus bar 400.

The bus bar 400 is formed with a groove 410 that receives a part of the clip member 500. As shown in Figures 5 and 6, the protrusion 510 on the clip member 500 engages with the groove 410 of the bus bar 400. This fixes the positions of the clip member 500 and the voltage detection line 600.

The grooves 410 may be formed on both sides of the busbar 400 as shown in FIG. 6, or may be formed on only one side of the busbar 400 as shown in FIG. 7. For convenience of illustration, the plate 700 and the wall 800 are not shown in FIGS. 6 and 7.

When connecting the voltage detection wire 600 to the bus bar 400, the resistance value required for the connection structure is on the order of mΩ. Therefore, adopting a welding structure with a resistance value on the order of μΩ may result in over-design.

In contrast, in the battery module 1 according to the present embodiment, the bus bar 400 and the voltage detection line 600 are electrically connected by engaging the clip member 500 with the bus bar 400. At this time, since a large current does not flow through the voltage detection line 600, the required resistance value specifications can be satisfied without necessarily welding between the bus bar 400 and the clip member 500. As a result of the above, it is possible to avoid an increase in the manufacturing cost of the battery module 1 due to over-design.

Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended to include all modifications within the meaning and scope of the claims.

1 Battery module, 100 Battery cell, 110 Electrode terminal, 111 Positive electrode terminal, 112 Negative electrode terminal, 120 Housing, 120A Case body, 120B Sealing plate, 121 Top surface, 122 Bottom surface, 123 First side surface, 124 Second side surface, 125 Third side surface, 126 Gas exhaust valve, 200 End plate, 300 Restraint member, 400 Bus bar, 410 Groove portion, 500 Clip member, 510 Protrusion portion, 600 Voltage detection line, 700 Plate, 800 Wall portion.

Claims (8)

A plurality of battery cells arranged in a first direction, each of the battery cells having a housing and an electrode terminal provided on the housing;
a plate-shaped bus bar that connects the electrode terminals of the plurality of battery cells;
A voltage detection line for detecting a voltage of the bus bar;
a conductive clip member electrically connected to the voltage detection line and biased to clamp at least a portion of the bus bar ;
the bus bar has a groove that receives a portion of the clip member . The battery module according to claim 1 , wherein the clip member includes a U-shaped portion that clamps the bus bar. The battery module according to claim 2 , wherein the U-shaped portion is fitted to the bus bar from a second direction perpendicular to the first direction. The battery module according to claim 1 , wherein the grooves are formed on both sides of the bus bar. The battery module according to claim 1 , further comprising a wall portion surrounding the bus bar and at least a portion of the clip member. The battery module according to claim 5 , wherein the wall portion is made of an insulating resin. The battery module according to claim 1 , wherein the housings of the plurality of battery cells have a rectangular shape. The battery module according to claim 1 , wherein the plurality of battery cells are lithium ion battery cells.

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