Battery pack and method for manufacturing a battery pack
The battery pack design stabilizes electrode connections on the sides of battery cells by using terminal pieces with planar portions to apply biasing forces, ensuring high energy density without jigs, thus optimizing space utilization.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2025-01-16
- Publication Date
- 2026-07-29
AI Technical Summary
Existing power supply devices face challenges in stably connecting electrodes provided on the sides of battery cells while maintaining energy density, as securing space for jigs is necessary during welding, which compromises energy density.
A battery pack design where adjacent battery cells have terminal pieces with planar portions that apply biasing forces to maintain relative positions during welding, allowing stable electrical connections without the need for jigs, thus preserving energy density.
The solution ensures stable electrode connections on the sides of battery cells while maintaining high energy density by welding terminal pieces without using jigs, thereby optimizing space utilization.
Smart Images
Figure 2026122805000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a battery pack and a method for manufacturing the battery pack.
Background Art
[0002] The following Patent Document 1 discloses an invention related to a power supply device. In this power supply device, when welding a bus bar and an electrode terminal provided on the upper part of a battery cell, a jig presses the bus bar against the battery cell.
Prior Art Document
Patent Document
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] However, when the above prior art is adopted for a power supply device including battery cells having electrode terminals provided on the sides, when welding the bus bar and the electrode terminals, it is necessary to secure a space for arranging the jig between the battery cells, which is not preferable from the viewpoint of the energy density of the power storage device. That is, there is room for improvement in the above prior art in terms of stably connecting the electrodes provided on the sides of the battery cells while ensuring the energy density.
[0005] In consideration of the above facts, an object of the present invention is to obtain a battery pack and a method for manufacturing the battery pack that can stably connect the electrodes provided on the sides of the battery cells while ensuring the energy density.
Means for Solving the Problems
[0006] A battery pack according to the first embodiment comprises a first battery cell and a second battery cell arranged adjacent to each other in the arrangement direction, wherein the first battery cell includes a first external terminal provided on one side of the arrangement direction in a first case housing a first electrode body and electrically connected to the first electrode of the first electrode body, a first joint welded to the first external terminal, and a first planar portion provided integrally with the first joint, having a planar shape with its thickness direction as the arrangement direction and capable of applying a biasing force to one side in the arrangement direction. The second battery cell comprises a metal second terminal piece comprising: a metal first terminal piece; a metal second terminal piece provided in the portion of the second case housing the second electrode body on the other side of the arrangement direction and electrically connected to the second electrode of the second electrode body; a metal second terminal piece provided integrally with the metal second terminal piece, having a planar shape with its thickness direction as the arrangement direction and capable of applying a biasing force to the other side of the arrangement direction, and welded to the first planar portion.
[0007] According to the first embodiment of the battery pack, it comprises a first battery cell and a second battery cell arranged adjacent to each other in the arrangement direction. The first battery cell includes a first external terminal provided on one side of the arrangement direction in the first case housing the first electrode body, i.e., on the side of the first battery cell, and electrically connected to the first electrode of the first electrode body, and a first metal terminal piece welded to the first external terminal.
[0008] On the other hand, the second battery cell includes a second external terminal provided on the other side of the arrangement direction in the second case housing the second electrode body, i.e., on the side of the second battery cell, and electrically connected to the second electrode of the second electrode body, and a metal second terminal piece welded to the second external terminal. Therefore, the first battery cell and the second battery cell can be electrically connected by welding the first terminal piece and the second terminal piece together.
[0009] Incidentally, when welding the first terminal piece and the second terminal piece, it is preferable to keep their relative positions constant. However, if the positioning of the first terminal piece and the second terminal piece is performed using a jig, it is necessary to secure space for the jig between the first battery cell and the second battery cell, which is undesirable from the viewpoint of the energy density of the battery pack.
[0010] In this embodiment, the first terminal piece comprises a first joint welded to the first external terminal, and a first planar portion provided integrally with the first joint, having a thickness direction oriented in the direction of the arrangement, and capable of applying a biasing force to one side in this arrangement direction.
[0011] On the other hand, the second terminal piece comprises a second joint welded to the second external terminal, and a second planar portion provided integrally with the second joint, having a thickness direction oriented in the direction of the above-mentioned arrangement, and capable of applying a biasing force to the other side of this arrangement direction.
[0012] Therefore, in this embodiment, the first planar portion of the first terminal piece and the second planar portion of the second terminal piece are in a state of pressing against each other, and they can be welded together while maintaining their relative positions constant.
[0013] A method for manufacturing a battery pack according to a second embodiment involves welding a first battery cell and a second battery cell, which are arranged adjacent to each other in the arrangement direction, with the first planar portion of a metal first terminal piece provided on one side in the arrangement direction of the first battery cell and electrically connected to the first electrode body, and the second planar portion of a metal second terminal piece provided on the other side in the arrangement direction of the second case for housing the second electrode body of the second battery cell and electrically connected to the second electrode body, while the first planar portion and the second planar portion are pressed against each other.
[0014] According to the manufacturing method of the battery pack according to the second embodiment, the first battery cell and the second battery cell are arranged adjacent to each other.
[0015] Then, in these arrangement directions, the first planar portion of a metal first terminal piece, which is provided on one side of the arrangement direction in the first case housing the first electrode body of the first battery cell and is electrically connected to the first electrode body, and the second planar portion of a metal second terminal piece, which is provided on the other side of the arrangement direction in the second case housing the second electrode body of the second battery cell and is electrically connected to the second electrode body, are pressed against each other, and the first planar portion and the second planar portion are welded together.
[0016] Therefore, in this embodiment, the first planar portion of the first terminal piece and the second planar portion of the second terminal piece can be welded together without using a jig, while maintaining a constant relative position between them. [Effects of the Invention]
[0017] As described above, the battery pack and the method for manufacturing the battery pack according to the present invention have the excellent effect of being able to secure energy density while stably connecting the electrodes provided on the sides of the battery cells. [Brief explanation of the drawing]
[0018] [Figure 1] This is a schematic perspective view showing the configuration of the battery pack according to the first embodiment. [Figure 2] This is a schematic front view showing the configuration of the main parts of a battery cell in a battery pack according to the first embodiment. [Figure 3] This is a schematic perspective view showing the configuration of the main parts of the battery cell in the battery pack according to the second embodiment. [Figure 4] This is a schematic front view showing the configuration of the main parts of the battery cell in the battery pack according to the second embodiment. [Modes for carrying out the invention]
[0019] <First Embodiment> Hereinafter, the configuration of the battery pack according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The "battery pack 10" according to the present embodiment is configured to be mounted on the lower surface of the floor portion of a vehicle (not shown) such as a hybrid car, a plug-in hybrid car, and an electric vehicle. This battery pack 10 includes a battery case made of an aluminum alloy that constitutes its outer shell, and a plurality of "battery cells 12" housed in the battery case.
[0020] In this embodiment, for convenience, the arrow X shown in each figure is referred to as the width direction (hereinafter simply referred to as the width direction) of the battery cell 12, the arrow Y is referred to as the thickness direction (hereinafter simply referred to as the thickness direction) of the battery cell 12, and the arrow Z is referred to as the height direction (hereinafter simply referred to as the height direction) of the battery cell 12. Also, the width direction, the thickness direction, and the height direction are such that one of these directions is orthogonal to the remaining two directions.
[0021] As shown in FIG. 1, the battery cell 12 includes a "case 14" that constitutes its outer shell, an "electrode body 16" disposed inside the case 14, a negative electrode side current collecting terminal (not shown), a positive electrode side current collecting terminal (not shown), an "external terminal 18", an "external terminal 20", and a pair of "terminal piece portions 22".
[0022] The case 14 includes a case main body portion 24 made of an aluminum alloy that constitutes its main part, and a pair of sealing plates 26 made of an aluminum alloy that constitute the end portions in the width direction thereof. The case main body portion 24 is formed in a rectangular tube shape with both sides in the width direction open.
[0023] On the other hand, the sealing plate 26 is formed in a rectangular plate shape when viewed from the width direction with the plate thickness direction being the width direction and the longitudinal direction being the height direction. And the opening of the case main body portion 24 is sealed by the sealing plate 26. That is, the sealing plate 26 constitutes a part of the side portion of the battery cell 12.
[0024] The electrode body 16 includes a power generation body that constitutes its main part and functions as a power storage portion in the battery cell 12, a "negative electrode current collecting portion 16A", and a "positive electrode current collecting portion 16B".
[0025] Furthermore, the negative electrode current collector 16A constitutes one end in the width direction of the electrode body 16, and the positive electrode current collector 16B constitutes the other end in the width direction of the electrode body 16.
[0026] The negative electrode current collector terminal is made of copper, for example, and its main portion is housed in one side of the case 14 in the width direction. The negative electrode current collector terminal is joined to the negative electrode current collector portion 16A of the electrode body 16 by a joint such as resistance welding (not shown), and is electrically connected to the negative electrode current collector portion 16A.
[0027] On the other hand, the positive electrode current collector terminal is made of aluminum, for example, and its main part is housed in the other side of the case 14 in the width direction. This positive electrode current collector terminal is joined to the positive electrode current collector portion 16B of the electrode body 16 by a joint such as resistance welding (not shown).
[0028] The external terminal 18 is shaped like a rectangular plate when viewed from the width direction, and, like the negative electrode current collection terminal, is made of copper as an example, and is located on the upper part in the height direction of the sealing plate 26 on one side in the width direction. The external terminal 18 is electrically connected to the negative electrode current collection terminal.
[0029] On the other hand, the external terminal 20, like the positive electrode current collection terminal, is made of aluminum as an example and is located on the upper part in the height direction of the sealing plate 26 on the other side in the width direction. The external terminal 18 is electrically connected to the positive electrode current collection terminal. Both the external terminal 18 and the external terminal 20 are provided with terminal pieces 22.
[0030] As shown in Figure 2, the terminal piece 22 is formed by bending a metal plate material through press working or the like, and is composed of a "joint portion 22A" and a "flat portion 22B".
[0031] More specifically, the joint portion 22A has a lower portion in the height direction that extends linearly in the height direction, while the upper portion in the height direction is curved so as to be convex inward in the width direction and upward in the height direction of the battery cell 12. The joint portion 22A is welded to the external terminal 18 or external terminal 20.
[0032] On the other hand, the flat portion 22B is provided integrally with the joint portion 22A and is a flat shape that extends upward in the height direction from the joint portion 22A with the thickness direction as the width direction. The terminal piece portion 22 configured as described above is capable of applying a biasing force from the flat portion 22B outward in the width direction of the battery cell 12 by its restoring force when the flat portion 22B is pressed inward in the width direction of the battery cell 12.
[0033] Furthermore, multiple battery cells 12 are arranged in a series in the width direction, and in this embodiment, the width direction can be considered as the arrangement direction of the battery cells 12. In battery cells 12 arranged adjacent to each other in the width direction, the tips of adjacent terminal pieces 22 are joined together by a joint (not shown) made by laser welding or the like, so that battery cells 12 arranged adjacent to each other in the width direction are electrically connected.
[0034] In this embodiment, of the battery cells 12 arranged adjacent to each other in the width direction, the battery cell 12 located on the other side in the width direction functions as the first battery cell, and the battery cell 12 located on the one side in the width direction functions as the second battery cell.
[0035] In the battery cell 12, which functions as the first battery cell, the electrode body 16 functions as the first electrode body, the negative electrode current collector portion 16A of this electrode body 16 functions as the first electrode, the case 14 functions as the first case, the external terminal 18 functions as the first external terminal, and the terminal piece portion 22 provided on this external terminal 18 functions as the first terminal piece portion. In addition, the joint portion 22A of this terminal piece portion 22 functions as the first joint portion, and the planar portion 22B of this terminal piece portion 22 functions as the first planar portion.
[0036] On the other hand, in the battery cell 12 which functions as a second battery cell, the electrode body 16 functions as a second electrode body, the positive electrode current collector portion 16B of this electrode body 16 functions as a second electrode, the case 14 functions as a second case, the external terminal 20 functions as a second external terminal, and the terminal piece portion 22 provided on this external terminal 20 functions as a second terminal piece portion. Furthermore, the joint portion 22A of this terminal piece portion 22 functions as a second joint portion, and the flat portion 22B of this terminal piece portion 22 functions as a second flat portion.
[0037] (Operation and effects of this embodiment) Next, the operation and effects of this embodiment will be described.
[0038] In this embodiment, as shown in Figure 1, there are multiple battery cells 12 arranged adjacent to each other in the width direction. Of these battery cells 12, the battery cell 12 located on the other side in the width direction is provided with an external terminal 18 located on one side of the case 14 housing the electrode body 16, that is, on the side of this battery cell 12, and electrically connected to the negative electrode current collector 16A of the electrode body 16, and a metal terminal piece 22 welded to the external terminal 18.
[0039] On the other hand, among the multiple battery cells 12 arranged adjacent to each other in the width direction, the battery cell 12 located on one side in the width direction has an external terminal 20 provided on the other side in the width direction of the case 14 housing the electrode body 16, that is, on the side of the battery cell 12, which is electrically connected to the positive electrode current collector 16B of the electrode body 16, and a metal terminal piece 22 welded to this external terminal 20. Therefore, by welding the terminal piece 22 of the battery cell 12 located on the other side in the width direction to the terminal piece 22 of the battery cell 12 located on one side in the width direction, multiple battery cells 12 arranged adjacent to each other in the width direction can be electrically connected.
[0040] By the way, when welding these terminal pieces 22 together, it is preferable to keep their relative positions constant. However, if these positions are determined using a jig, it is necessary to secure space for the jig between the battery cells 12 that are arranged adjacent to each other in the width direction, which is undesirable from the viewpoint of the energy density of the battery pack 10.
[0041] In this embodiment, the terminal piece 22 on one side in the width direction of the battery cell 12 on the other side in the width direction has a joint portion 22A welded to the external terminal 18, and the flat portion 22B of this joint portion 22A is capable of applying a biasing force to one side in the width direction.
[0042] On the other hand, of the battery cells 12 on one side in the width direction, the terminal piece 22 on the other side in the width direction has a joint 22A welded to the external terminal 20, and the flat portion 22B of this joint 22A is capable of applying a biasing force to the other side in the width direction.
[0043] Therefore, in this embodiment, between battery cells 12 arranged adjacent to each other in the width direction, the flat portion 22B of the terminal piece 22 on the other side in the width direction and the flat portion 22B of the terminal piece 22 on the one side in the width direction are pressed against each other, and they can be welded together while maintaining their relative positions constant.
[0044] More specifically, during the manufacturing of the battery pack 10, the battery cells 12 are arranged adjacent to each other in the width direction relative to the battery case. Then, as described above, in the arrangement direction of these battery cells 12, the flat portion 22B of the terminal piece 22 on the other side in the width direction and the flat portion 22B of the terminal piece 22 on the one side in the width direction are pressed against each other, and these flat portions 22B are welded together.
[0045] Therefore, in this embodiment, without using a jig, it is possible to weld battery cells 12 arranged adjacent to each other in the width direction while maintaining a constant relative position between the planar portion 22B of the terminal piece 22 on the other side in the width direction and the planar portion 22B of the terminal piece 22 on the one side in the width direction.
[0046] As described above, in this embodiment, it is possible to ensure the energy density of the battery pack 10 while stably connecting the electrodes provided on the sides of the battery cell 12.
[0047] <Second Embodiment> Hereinafter, a "battery pack 30" according to the second embodiment of the present invention will be described with reference to Figures 3 and 4. Note that components identical to those in the first embodiment described above will be given the same part numbers and their descriptions will be omitted.
[0048] Although this battery pack 30 has basically the same configuration as the first embodiment described above, the shape of the terminal piece 34 provided on the battery cell 32 is different from that of the terminal piece 22.
[0049] This terminal piece 34 is formed by bending a metal plate material through press processing or the like, and includes a pair of "joint portions 34A" and a "flat portion 34B".
[0050] More specifically, the joint portion 34A is U-shaped, with the lower side in the height direction being convex when viewed from the thickness direction. They are spaced apart from each other in the thickness direction, and the portion on the case 14 side is welded to the external terminal 18 or external terminal 20.
[0051] On the other hand, the flat portion 34B is provided in a continuous manner with the opposite side of the case 14 at the pair of joint portions 34A, and is a flat shape that extends upward in the height direction from the joint portion 34A with the thickness direction as the width direction. The terminal piece portion 34 configured as described above is capable of applying a biasing force outward in the width direction from the flat portion 34B of the battery cell 12 when the flat portion 34B is pressed inward in the width direction of the battery cell 12 due to its restoring force.
[0052] This configuration provides essentially the same functions and effects as the first embodiment described above. Furthermore, in this embodiment, the joint portion 34A is U-shaped with the lower side in the height direction being convex when viewed from the thickness direction, which ensures a certain amount of deformation in the width direction of the terminal piece portion 34. [Explanation of Symbols]
[0053] 10 battery packs 12 Battery cells (1st battery cell, 2nd battery cell) 16 Electrode body (first electrode body, second electrode body) 16A Negative electrode current collector (first electrode) 16B Positive electrode current collector (second electrode) 14 cases (Case 1, Case 2) 18 External terminal (1st external terminal) 20 External terminal (2nd external terminal) 22 Terminal piece part (1st terminal piece part, 2nd terminal piece part) 22A Joint (1st joint, 2nd joint) 22B Plane part (1st plane part, 2nd plane part) 30 battery packs 32 battery cells (first battery cell, second battery cell) 34 Terminal piece part (1st terminal piece part, 2nd terminal piece part) 34A Joint (1st joint, 2nd joint) 34B Plane part (1st plane part, 2nd plane part)
Claims
1. It comprises a first battery cell and a second battery cell arranged adjacent to each other in the direction of arrangement, The first battery cell is, A first external terminal is provided in the first case housing the first electrode body, on one side of the arrangement direction, and is electrically connected to the first electrode of the first electrode body. A metal first terminal piece comprising a first joint welded to the first external terminal, and a first planar portion provided integrally with the first joint, having a planar shape with its thickness direction as the arrangement direction and capable of applying a biasing force to one side in the arrangement direction, The second battery cell is, A second external terminal is provided in the second case housing the second electrode body, on the other side of the arrangement direction, and is electrically connected to the second electrode of the second electrode body. The device comprises a second metal terminal piece having a second joint welded to the second external terminal, and a second planar portion provided integrally with the second joint, having a planar shape with its thickness direction as the arrangement direction, and capable of applying a biasing force to the other side of the arrangement direction, and welded to the first planar portion. Battery pack.
2. Between the first battery cell and the second battery cell, which are arranged adjacent to each other in the direction of arrangement, A planar first flat portion of a metal first terminal piece provided on one side in the arrangement direction of the first case housing the first electrode body of the first battery cell and electrically connected to the first electrode body, A planar second flat portion of a metal second terminal piece, which is provided on the other side of the arrangement direction in the second case housing the second electrode body of the second battery cell and is electrically connected to the second electrode body, is pressed against each other. The first planar portion and the second planar portion are welded together. A method for manufacturing battery packs.