Battery pack manufacturing method

Abstract

The objective is to obtain a method for manufacturing a battery pack that can stably connect electrodes provided on the sides of battery cells while ensuring energy density. [Solution] In the manufacturing method of the battery pack 10, in the width direction of a plurality of battery cells 12 arranged adjacent to each other in the width direction, a recess 22C provided in the welded portion 22B of a metal terminal piece 22 provided on one side in the width direction of the case 14 that houses the electrode body 16 of the battery cell 12 on the other side in the width direction and a protrusion 28C provided in the welded portion 28B of a metal terminal piece 28 provided on the other side in the width direction of the case 14 that houses the electrode body 16 of the battery cell 12 on the other side in the width direction are fitted together, and the welded portion 22B and the welded portion 28B are welded together.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a battery pack.

Background Art

[0002] Patent Document 1 below 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 Documents

Patent Documents

[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 a 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 method for manufacturing a 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] Between a first battery cell and a second battery cell, which are arranged adjacent to each other in the arrangement direction, the first weld and the second weld are welded in a state in which a recess is provided in the first weld of a metal first terminal piece, which is provided in the portion of the first case housing the first electrode body of the first battery cell on one side in the arrangement direction and is electrically connected to the first electrode body, and a protrusion is provided in the second weld of a metal second terminal piece, which is provided in the portion of the second case housing the second electrode body of the second battery cell on the other side in the arrangement direction and is electrically connected to the second electrode body.

[0007] According to the manufacturing method of the battery pack according to the first embodiment, the first battery cell and the second battery cell are arranged adjacent to each other.

[0008] Then, in these arrangement directions, the first weld and the second weld are welded together with a recess provided in the first weld of a metal first terminal piece, which is provided in the portion of the first case housing the first electrode body of the first battery cell on one side of the arrangement direction and electrically connected to the first electrode body, and a protrusion provided in the second weld of a metal second terminal piece, which is provided in the portion of the second case housing the second electrode body of the second battery cell on the other side of the arrangement direction and electrically connected to the second electrode body, in a state where these are fitted together.

[0009] Therefore, in this embodiment, the first welded portion of the first terminal piece and the second welded 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]

[0010] As described above, the battery pack manufacturing method according to the present invention has the excellent effect of ensuring energy density while stably connecting the electrodes provided on the sides of the battery cells. [Brief explanation of the drawing]

[0011] [Figure 1]This is a schematic perspective view showing the configuration of a battery pack manufactured by the battery pack manufacturing method 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 manufactured by the battery pack manufacturing method 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]

[0012] <First Embodiment> The configuration of the battery pack according to the first embodiment of the present invention will be described below with reference to Figures 1 and 2. The "battery pack 10" according to this embodiment can be mounted on the underside of the floor of a vehicle (not shown), such as a hybrid car, a plug-in hybrid car, and an electric vehicle. This battery pack 10 comprises an aluminum alloy battery case that forms its outer shell, and a plurality of "battery cells 12" housed in the battery case.

[0013] In this embodiment, for convenience, arrow X shown in each figure will be referred to as the width direction of the battery cell 12 (hereinafter simply as the width direction), arrow Y as the thickness direction of the battery cell 12 (hereinafter simply as the thickness direction), and arrow Z as the height direction of the battery cell 12 (hereinafter simply as the height direction). Furthermore, one of the width direction, thickness direction, and height direction is perpendicular to the other two directions.

[0014] As shown in Figure 1, the battery cell 12 comprises a "case 14" that constitutes its outer shell, an "electrode body 16" arranged inside the case 14, a negative electrode current collector terminal (not shown), a positive electrode current collector terminal (not shown), an external terminal 18, an external terminal 20, a "terminal piece 22" as a first terminal piece, and a "terminal piece 28" as a second terminal piece.

[0015] Case 14 is composed of a case main body 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. The case main body 24 is in the shape of a rectangular tube with both sides in the width direction open.

[0016] On the other hand, the sealing plate 26 is in the shape of a rectangular plate when viewed from the width direction where the plate thickness direction is the width direction and the longitudinal direction is the height direction. And the opening of the case main body 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.

[0017] The electrode body 16 is composed of a power generation body that constitutes its main part and functions as a power storage part in the battery cell 12, a negative electrode current collector 16A, and a positive electrode current collector 16B.

[0018] The negative electrode current collector 16A constitutes one end portion in the width direction of the electrode body 16, and the positive electrode current collector 16B constitutes the other end portion in the width direction of the electrode body 16.

[0019] The negative electrode side current collecting terminal is made of copper as an example, and its main part is accommodated in a part on one side in the width direction of the case 14. And the negative electrode side current collecting terminal is joined to the negative electrode current collector 16A of the electrode body 16 by a joining part such as resistance welding not shown, and is in a state of being electrically connected to the negative electrode current collector 16A.

[0020] On the other hand, the positive electrode side current collecting terminal is made of aluminum as an example, and its main part is accommodated in a part on the other side in the width direction of the case 14. This positive electrode side current collecting terminal is joined to the positive electrode current collector 16B of the electrode body 16 by a joining part such as resistance welding not shown. <​​​​

[0022] On the other hand, like the positive electrode side current collecting terminal, the external terminal 20 is made of aluminum as an example and is disposed at the upper portion 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 side current collecting terminal. The external terminal 18 is provided with a terminal piece portion 22, and the external terminal 20 is provided with a terminal piece portion 28.

[0023] As shown in FIG. 2, the terminal piece portion 22 is formed by bending a metal plate material by press working or the like, and includes a joint portion 22A and a "welding portion 22B" as a first welding portion.

[0024] Specifically, the joint portion 22A has a lower portion in the height direction extending linearly in the height direction, and an upper portion in the height direction is curved so as to protrude 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.

[0025] On the other hand, the welding portion 22B is provided integrally with the joint portion 22A and has a planar shape extending upward in the height direction from the joint portion 22A with the thickness direction being the width direction. When the welding portion 22B is pressed inward in the width direction of the battery cell 12, the terminal piece portion 22 configured as described above can apply a biasing force outward in the width direction of the battery cell 12 from the welding portion 22B by its restoring force.

[0026] Furthermore, a spherical "concave portion 22C" protruding toward the case 14 side is formed in the welding portion 22B.

[0027] On the other hand, the terminal piece portion 28 basically has the same configuration as the terminal piece portion 22, including a joint portion 28A and a "welding portion 28B" as a second welding portion. The joint portion 28A is welded to the external terminal 20.

[0028] Furthermore, the welded portion 28B has a spherical "protrusion 28C" formed on the side opposite to the case 14, which is convex and can be fitted into the recess 22C. The shapes of the recess 22C and the protrusion 28C can be various, such as having a rectangular parallelepiped shape, as long as they can be fitted together.

[0029] 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 recess 22C of the adjacent terminal piece 22 and the protrusion 28C of the terminal piece 28 are fitted together, and the tip of the terminal piece 22 and the tip of the terminal piece 28 are joined by a joint (not shown) such as laser welding, thereby electrically connecting the battery cells 12 arranged adjacent to each other in the width direction.

[0030] 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.

[0031] In the battery cell 12, which functions as the first battery cell, the electrode body 16 functions as the first electrode body, and the case 14 functions as the first case.

[0032] 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, and the case 14 functions as a second case.

[0033] (Operation and effects of this embodiment) Next, the operation and effects of this embodiment will be described.

[0034] In the manufacturing method of the battery pack 10 according to this embodiment, as shown in Figure 1, a plurality of battery cells 12 are arranged adjacent to each other in the width direction in a battery case. Then, in the width direction, a recess 22C provided in the welded portion 22B of a metal terminal piece 22, which is provided in one part of the width direction of the case 14 that houses the electrode body 16 of the battery cell 12 on the other side in the width direction and is electrically connected to the electrode body 16, and a protrusion 28C provided in the welded portion 28B of a metal terminal piece 28, which is provided in the other part of the width direction of the case 14 that houses the electrode body 16 of the battery cell 12 on the other side in the width direction and is electrically connected to the electrode body 16, are fitted together, and the welded portion 22B and the welded portion 28B are welded together.

[0035] 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 welded portion 22B of the terminal piece 22 on the other side in the width direction and the welded portion 28B of the terminal piece 28 on one side in the width direction.

[0036] 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.

[0037] <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.

[0038] Although this battery pack 30 has basically the same configuration as the first embodiment described above, the shape of the "terminal piece 34" which serves as the first terminal piece provided on the "battery cell 32" is different from the shape of the terminal piece 22, and the shape of the "terminal piece 36" which serves as the second terminal piece is different from the terminal piece 28.

[0039] The terminal piece 34 is formed by bending a metal plate material through press working or the like, and includes a pair of joint portions 34A and a "welded portion 34B" which serves as the first welded portion.

[0040] More specifically, the joint portion 34A is U-shaped with a convex lower side in the height direction when viewed from the thickness direction, and is arranged with a gap between them in the thickness direction, and the portion on the case 14 side is welded to the external terminal 18.

[0041] On the other hand, the welded portion 34B is provided in a continuous manner with the opposite portion of the case 14 in the pair of joint portions 34A, and is a planar shape that extends upward in the height direction from the joint portion 34A with the thickness direction as the width direction. In addition, a "recess 34C" is formed in the welded portion 34B, which has the same shape as the recess 22C.

[0042] On the other hand, the terminal piece 36 has the same configuration as the terminal piece 34, including a pair of joints 36A and a "welded portion 36B" as a second welded portion. Furthermore, a "protrusion 36C" is formed on the welded portion 36B, which has the same shape as the protrusion 28C.

[0043] This configuration provides essentially the same functions and effects as the first embodiment described above. Furthermore, in this embodiment, the joint portions 34A and 36A are 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 pieces 34 and 36. [Explanation of Symbols]

[0044] 10 battery packs 12 Battery cells (1st battery cell, 2nd battery cell) 16 Electrode body (first electrode body, second electrode body) 14 cases (Case 1, Case 2) 22 Terminal piece (first terminal piece) 22B Weld (First Weld) 22C recess 28 Terminal piece (second terminal piece) 28B Welded section (Second welded section) 28C protrusion 30 battery packs 32 battery cells (first battery cell, second battery cell) 34 Terminal piece (first terminal piece) 34B Weld (First Weld) 34C recess 36 Terminal piece (second terminal piece) 36B Welded section (Second welded section) 36C protrusion

Claims

[Claim 1] Between the first battery cell and the second battery cell, which are arranged adjacent to each other in the direction of arrangement, A recess is provided in the first weld portion of a metal first terminal piece that is electrically connected to the first electrode body, which is provided in the first case that houses the first electrode body of the first battery cell and is located on one side in the arrangement direction, In a state in which a protrusion is provided on the second weld portion of a metal second terminal piece that is electrically connected to the second electrode body and is located on the other side of the arrangement direction in the second case that houses the second electrode body of the second battery cell, The first welded portion and the second welded portion are welded together. A method for manufacturing battery packs.

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