Battery module

Abstract

The invention relates to a battery module having a plurality of battery cells and a bus bar. The battery cell has an electrode terminal. The bus bar connects the electrode terminals of the plurality of battery cells to each other. The electrode terminal has a base portion and a protruding portion protruding from the base portion. The protrusion portion is disposed closer to the end portion side of the base portion than the center of the base portion. And the bus is connected with the base part of the electrode terminal in a welding manner. Therefore, the welding area of the electrode terminal and the bus bar can be increased.

Description

Technical Field

[0001] The present invention relates to a battery module, for example, to a battery module having a plurality of battery cells and a bus bar, wherein the plurality of battery cells have electrode terminals and the bus bar connects the electrode terminals of the plurality of battery cells to each other. Background Art

[0002] The structure of a general battery module is to connect the electrode terminals of multiple battery cells to each other using a busbar. In the battery module of Patent Document 1, in order to absorb the height deviation when connecting adjacent battery cells, the through hole of the busbar is formed into a long hole, and the peripheral edge of the protrusion of the electrode terminal is welded to the peripheral edge of the through hole of the busbar.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-216039

[0004] In the battery module of Patent Document 1, the peripheral edge of the protrusion of the electrode terminal and the peripheral edge of the through hole of the bus bar are welded and connected, which has the problem that the welding area between the electrode terminal and the bus bar is narrow. Summary of the invention

[0005] The present invention has been made in view of the above-mentioned problems, and provides a battery module capable of increasing the welding area between electrode terminals and bus bars.

[0006] A battery module of one embodiment of the present invention comprises: a plurality of battery cells, each having an electrode terminal; and a busbar, the busbar connecting the electrode terminals of the plurality of battery cells to each other, the electrode terminal having a base and a protrusion protruding from the base, the protrusion being arranged closer to the end side of the base than the center of the base, and the busbar being welded and connected to the base of the electrode terminal.

[0007] Furthermore, the protrusion may have a flat surface parallel to the base at the tip of the protrusion, and the flat surface may constitute a reference surface for measuring the height position of the generatrix relative to the base.

[0008] According to the present invention, a battery module capable of increasing the welding area between the electrode terminals and the bus bars can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a diagram showing the positive electrode terminal side of a battery cell in the battery module according to the embodiment. DETAILED DESCRIPTION

[0010] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. In addition, in order to clearly explain, the following description and the accompanying drawings are appropriately simplified. Here, in the following description, in order to clearly explain, a three-dimensional (XYZ) coordinate system is used for explanation.

[0011] Figure 1 1 is a diagram showing the positive terminal side of a battery cell in a battery module according to the present embodiment. Figure 1 As shown, the battery module 1 of the present embodiment is formed by connecting a plurality of battery cells 2 with bus bars 3. The battery cells 2 are, for example, general lithium-ion battery cells.

[0012] That is, the battery cell 2 is formed, for example, by winding a stack of a positive electrode, a separator, and a negative electrode, which is contained in a case 4 and an electrolyte is injected into the case 4. Figure 1 As shown, the opening of the case 4 is covered with a cover 5 , the positive electrode of the wound body is connected to a positive terminal 6 provided on the cover 5 via a positive electrode collector, and the negative electrode of the wound body is connected to a negative terminal provided on the cover 5 via a negative electrode collector.

[0013] At this time, the battery cell 2 is, for example, Figure 1 As shown, the shape is a roughly rectangular shape that is long in the Y-axis direction when viewed from the Z-axis direction, and a plurality of battery cells 2 are arranged in the X-axis direction, and the positive terminals 6 and the negative terminals are arranged alternately in the battery cells 2 adjacent to each other in the X-axis direction. Figure 1 In the battery cell 2 shown, the positive electrode terminal 6 is arranged on the negative side in the Y-axis direction, and the negative electrode terminal is arranged on the positive side in the Y-axis direction.

[0014] The positive terminal 6 is connected to the negative terminal of the battery cell 2 arranged on the positive side of the X-axis, for example. Here, the positive terminal 6 and the negative terminal constitute the so-called electrode terminal of the battery cell 2, and are centrally symmetrical with the approximate center of the battery cell 2 as the center when viewed from the Z-axis direction, for example. Figure 1 The structure of the positive electrode terminal 6 shown is described as a representative example.

[0015] The positive terminal 6 is composed of a conductive member such as Figure 1 As shown in FIG. 6 , the base portion 6a and the protrusion portion 6b are provided. The base portion 6a is, for example, in the shape of a flat plate substantially parallel to the XY plane and extends in the Y-axis direction.

[0016] like Figure 1As shown, the protrusion 6b protrudes from the base 6a toward the positive direction of the Z axis, and is in a substantially truncated cone shape whose diameter decreases as it moves toward the positive direction of the Z axis. At this time, the protrusion 6b has a flat surface 6c substantially parallel to the XY plane at the end of the protrusion 6b on the positive direction side of the Z axis, and the flat surface 6c is arranged substantially parallel to the surface of the base 6a on the positive direction side of the Z axis.

[0017] For example Figure 1 As shown in FIG. 1 , when viewed from the Z-axis direction, the protrusion 6b is arranged at the end side on the negative direction side of the Y-axis relative to the center of the base 6a. That is, the protrusion 6b is arranged near the end of the base 6a on the negative direction side of the Y-axis. Therefore, in the surface on the positive direction side of the Z-axis of the base 6a of the positive terminal 6, the area on the positive direction side of the Y-axis than the protrusion 6b is larger than the area on the negative direction side of the Y-axis than the protrusion 6b.

[0018] The busbar 3 is composed of a conductive member. Figure 1 As shown, the busbar 3 is a flat plate shape substantially parallel to the XY plane when viewed from the Z-axis direction, and extends in the X-axis direction. In addition, the busbar 3 has through holes 3a extending in the Z-axis direction at the ends on the positive side of the X-axis and the negative side of the X-axis of the busbar 3.

[0019] like Figure 1 As shown, the through hole 3a is formed into a shape into which the protrusion 6b of the positive terminal 6 and the protrusion of the negative terminal can be inserted, for example, having a peripheral shape larger than the peripheral shape of the end of the protrusion 6b of the positive terminal 6 and the protrusion of the negative terminal on the negative direction side of the Z axis.

[0020] The protrusion of the negative terminal of the battery cell 2 on the positive direction side of the X-axis in the adjacent battery cell 2 is inserted into the through hole 3a on the positive direction side of the X-axis of such a bus bar 3, and the base of the negative terminal of the battery cell 2 on the positive direction side of the X-axis is covered by the end of the bus bar 3 on the positive direction side of the X-axis.

[0021] Moreover, regarding the end of the busbar 3 on the positive side of the X-axis and the area of ​​the base of the negative terminal of the battery cell 2 on the positive side of the X-axis that is closer to the positive side of the Y-axis than the protrusion, the opposing parts are welded together by laser welding or the like to form a connection portion.

[0022] On the other hand, Figure 1 As shown, the protrusion 6b of the positive terminal 6 of the battery cell 2 on the negative side of the X-axis in the adjacent battery cell 2 is inserted into the through hole 3a on the negative side of the X-axis of the bus bar 3, and the base 6a of the positive terminal 6 of the battery cell 2 on the negative side of the X-axis is covered by the end of the bus bar 3 on the negative side of the X-axis.

[0023] And, if Figure 1As shown, regarding the end portion on the negative side of the X-axis of the busbar 3 and the area on the positive side of the Y-axis in the base 6a of the positive terminal 6 of the battery cell 2 on the negative side of the X-axis, which is closer to the positive side of the Y-axis than the protrusion 6b, the opposing portions of the two are welded together by laser welding or the like to form a connecting portion 7.

[0024] In this way, the protrusion of the negative terminal of the battery cell 2 on the positive direction side of the X-axis in the adjacent battery cell 2 is inserted into the through hole 3a on the positive direction side of the X-axis of the bus bar 3, and the protrusion 6b of the positive terminal 6 of the battery cell 2 on the negative direction side of the X-axis in the adjacent battery cell 2 is inserted into the through hole 3a on the negative direction side of the X-axis of the bus bar 3, thereby enabling the bus bar 3 to be simply positioned by the protrusion of the negative terminal and the protrusion 6b of the positive terminal 6.

[0025] Moreover, the area of ​​the portion where the end of the busbar 3 on the negative side of the X-axis and the area of ​​the base 6a of the positive terminal 6 of the battery cell 2 on the negative side of the X-axis that is closer to the positive side of the Y-axis than the protrusion 6b are opposite to each other is larger than the area where the protrusion 6b of the positive terminal 6 and the peripheral portion of the through hole of the busbar are opposite to each other.

[0026] Therefore, the battery module 1 of the present embodiment can increase the welding area between the positive electrode terminal 6 and the bus bar 3 compared to the battery module of Patent Document 1. This also applies to the negative electrode terminal side.

[0027] At this time, for example, when the protrusion 6 b of the positive terminal 6 is arranged substantially at the center of the base 6 a in the Y-axis direction, the positive terminal 6 and the bus bar 3 need to be connected by welding on both sides through the protrusion 6 b of the positive terminal 6 .

[0028] In the battery module 1 of the present embodiment, the protrusion 6b of the positive terminal 6 is arranged near the end of the base 6a on the negative side of the Y axis. Therefore, in the present embodiment, the positive terminal 6 and the bus bar 3 can be connected by welding the end of the bus bar 3 on the negative side of the X axis and the base 6a of the positive terminal 6 of the battery cell 2 on the negative side of the X axis, which is closer to the positive side of the Y axis than the protrusion 6b. That is, it is sufficient to provide one connection portion 7. The same applies to the negative terminal side.

[0029] Here, when a large gap is formed between the base 6a of the positive terminal 6 and the bus bar 3, the positive terminal 6 and the bus bar 3 cannot be well welded. Therefore, it is preferable to measure the height position of the bus bar 3 in the Z-axis direction relative to the base 6a of the positive terminal 6 before welding the positive terminal 6 and the bus bar 3 to check whether welding can be performed.

[0030] In this case, in the positive terminal 6 of the battery module 1 of the present embodiment, the flat surface 6c of the protrusion 6b is arranged substantially parallel to the surface of the base 6a on the positive side of the Z axis. Therefore, the height position of the busbar 3 in the Z axis direction can be measured with the flat surface 6c of the protrusion 6b as a reference plane.

[0031] Therefore, the protrusion 6b of the positive electrode terminal 6 can not only play a positioning function for the bus bar 3, but also function as a reference surface for measuring the height position of the bus bar 3 in the Z-axis direction. This is also the case on the negative electrode terminal side.

[0032] In the present embodiment, the positive electrode terminal 6 is arranged on the negative side of the battery module 1 in the Y-axis direction, but the arrangement of the negative electrode terminal can be implemented in substantially the same manner.

[0033] In the present embodiment, the protrusion 6b of the positive terminal 6 is arranged on the negative side in the Y-axis direction, but the protrusion 6b only needs to be arranged on the end side of the center of the base 6a when viewed from the Z-axis direction. The same applies to the negative terminal.

[0034] The protrusion 6b of the positive terminal 6 in this embodiment is substantially in the shape of a truncated cone, but the shape is not limited thereto and the protrusion 6b may be cylindrical as long as it protrudes from the base 6a in the positive direction of the Z axis. The same applies to the negative terminal.

[0035] The present invention is not limited to the above-described embodiments, and can be appropriately modified within a scope not departing from the gist of the invention.

Claims

1. A battery module, characterized in that: have: a plurality of battery cells having electrode terminals; and a bus bar connecting the electrode terminals of the plurality of battery cells to each other, The electrode terminal has a base and a protrusion protruding from the base. The protrusion is arranged closer to the end side of the base than to the center of the base. The busbar is connected to the base of the electrode terminal by welding.

2. The battery module according to claim 1, characterized in that: The protrusion has a flat surface parallel to the base at the top of the protrusion, The flat surface constitutes a reference surface for measuring the height position of the generatrix relative to the base.

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