Battery module

Abstract

The utility model provides a battery module capable of improving the accommodating efficiency of a module shell for accommodating a plurality of battery units. A battery module (11) has a plurality of battery cells (20) in which plate-shaped electrode bodies (40) constituting a positive electrode and a negative electrode are externally coated with a laminated film (22) and electrode leads (26) protrude from one and the other in the width direction (W), and the plurality of battery cells (20) are laminated in the thickness direction (D) and housed in a module case (16). At least a part of the plurality of battery cells (20) are connected continuously via a connection part (70) that connects the electrode leads (26) to each other, and are electrically connected by being folded and stacked in a corrugated manner at the position of the connection part (70).

Description

Technical Field

[0001] This utility model relates to a battery module. Background Technology

[0002] Japanese Patent No. 3912201 discloses a battery module in which multiple two-terminal type batteries having sheet-shaped positive and negative terminals extending from the outer periphery of the battery body are arranged side by side. Multiple battery cells are stacked in such a way that the same terminal of each terminal is connected to each other by a pair of generally plate-shaped busbars in the direction of the terminal extension.

[0003] In the battery module described in Japanese Patent No. 3912201, the connection between two adjacent chip-type batteries in the stacking direction is achieved via a conductive columnar member that connects a pair of busbars to a pair of busbars. Therefore, space is required between the two adjacent chip-type batteries in the stacking direction to accommodate a pair of busbars and the conductive columnar member, reducing the storage efficiency of the two chip-type batteries within the module housing. Utility Model Content

[0004] The present invention takes into account the above facts and aims to obtain a battery module that can improve the housing efficiency of multiple battery cells in the module housing.

[0005] The battery module of the first embodiment has a plurality of battery cells with plate-shaped electrode bodies constituting positive and negative electrodes encased in a laminated film, and electrode leads protruding from one side and the other in the width direction. The plurality of battery cells are stacked in the thickness direction and housed in a module housing, wherein at least a portion of the plurality of battery cells are continuously connected via a connecting portion that connects the electrode leads to each other, and the connecting portion is corrugated and stacked, thereby electrically connected.

[0006] The battery module of the first embodiment includes multiple battery cells with plate-shaped electrode bodies constituting positive and negative electrodes encased in a laminated film, and electrode leads protruding from one side and the other in the width direction. Furthermore, in the battery module, the multiple battery cells are stacked in the thickness direction and housed within a module housing. Here, at least a portion of the multiple battery cells are continuously connected via connecting portions that connect the electrode leads to each other; these connecting portions are corrugated and stacked, thereby achieving electrical connection. In this way, by directly connecting the electrode leads to each other, the number of busbars connecting the battery cells can be reduced, enabling miniaturization. This improves the housing efficiency of the module housing in housing multiple battery cells.

[0007] As described above, the battery module involved in this utility model can improve the housing efficiency of multiple battery cells. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the battery cell involved in the implementation method as viewed from the thickness direction.

[0009] Figure 2 A schematic diagram illustrating the internal structure of the battery cell involved in the embodiment.

[0010] Figure 3 This is a top view showing the connection point between two series-connected unit groups, which is part of the battery module involved in the implementation. Detailed Implementation

[0011] The following reference Figures 1-3 One embodiment of this utility model will be described. Furthermore, in Figures 1-3 In the figures, the direction indicated by arrow W is defined as the width direction of battery cell 20, the direction indicated by arrow H is defined as the height direction (vertical direction) of battery cell 20, and the direction indicated by arrow D is defined as the thickness direction of battery cell 20. The width direction W of battery cell 20 is consistent with the width direction of electrode sheet 50 and separator 60 described later.

[0012] Figure 1 This is a schematic diagram showing a single battery cell viewed from the thickness direction D. (Example) Figure 1 As shown, the battery cell 20 is formed as a flat and elongated rectangular plate with the width direction W as the length direction, constituting a secondary battery capable of being charged and discharged.

[0013] Battery cell 20 has a rectangular plate-shaped electrode body 40 (see reference). Figure 2 The electrode body 40 is externally mounted (sealed) by a laminated film 22. The electrode body 40 is connected to electrode leads 26 protruding in the width direction W at one and the other ends. The electrode leads 26 have a first electrode lead 26A connected to the positive electrode of the electrode body 40 in the width direction W and a second electrode lead 26B connected to the negative electrode of the electrode body 40 in the width direction W. The first electrode lead 26A and the second electrode lead 26B are formed as rectangular plates with the width direction W as their length direction. The laminated film 22 is embossed on at least one side in the thickness direction. By embossing, a concave receiving portion 221 is formed on the side to house the electrode body 40 (see reference). Figure 2 ).

[0014] Figure 2 This is a schematic diagram illustrating the internal structure of the battery cell 20, shown as a view from the height direction H with the battery cell 20 disassembled. Figure 2As shown, the laminated film 22 has a first laminated film 22A disposed on one side of the electrode body 40 in the thickness direction D and a second laminated film 22B disposed on the other side of the electrode body 40 in the thickness direction D. The first laminated film 22A and the second laminated film 22B overlap on both sides of the electrode body 40 in the thickness direction D and are thermally fused together at their outer peripheries to form a receiving space of the electrode body 40. In this embodiment, one side of the second laminated film 22B is embossed to form a receiving portion 221. The laminated film 22 can adopt either a single-cup embossed structure with embossing at point 1 or a double-cup embossed structure with embossing at point 2. In this embodiment, a single-cup embossed structure is adopted in which a receiving portion 221 with a drawing depth of about 8 mm to 10 mm is formed on one side of the second laminated film 22B.

[0015] In one direction of the width W of the battery cell 20, one end of the first electrode lead 26A protrudes from the end of the laminated film 22 in the width W direction. In the other direction of the width W of the battery cell 20, one end of the second electrode lead 26B protrudes from the end of the laminated film 22 in the width W direction.

[0016] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530mm-600mm, 600mm-700mm, 700mm-800mm, 800mm-900mm, or 1000mm or more; the length CW2 of the area housing the electrode body is, for example, 500mm-520mm, 600mm-700mm, 700mm-800mm, 800mm-900mm, or 1000mm or more; and the height CH of the battery cell 20 is, for example, 80mm-110mm or 110mm-140mm. Furthermore, the thickness of the battery cell 20 is 5.0mm-7.0mm, 7.0mm-9.0mm, or 9.0mm-11.0mm, and the height TH of the electrode leads (terminals) 26 is 40mm-50mm, 50mm-60mm, or 60mm-70mm.

[0017] The electrode body 40 is constructed by alternately stacking multiple electrode plates 50 and separators 60. The multiple electrode plates 50 have multiple positive electrode plates 52 and multiple negative electrode plates 54, and the positive electrode plates 52 and negative electrode plates 54 are alternately stacked in the electrode body 40 with the separators 60 in between.

[0018] The positive electrode sheet 52 is formed, for example, by coating both sides of a sheet-like positive electrode current collector made of aluminum foil with a positive electrode active material. The positive electrode active material is a material capable of intercalating and deintercalating ions. As long as it is a lithium-ion secondary battery, it can be composed of lithium nickel oxide, lithium cobalt oxide (e.g., LiCoO2), and lithium manganese oxide (e.g., LiMn2O4).

[0019] The end of the positive electrode 52 along its width direction W becomes a protruding end 52A that protrudes from the end of the separator along its width direction. This protruding end 52A is not coated with positive electrode active material, exposing the positive electrode current collector. The protruding end 52A, together with the protruding end 52A of another positive electrode 52, is integrated in the stacking direction of the electrode body 40. Figure 2 The current collector on the positive electrode side is formed at a predetermined position (D) in the thickness direction. In this embodiment, the protruding ends 52A of the plurality of positive electrode plates 52 are integrated on the side of the first laminated film 22A to form the current collector on the positive electrode side, and the first electrode lead 26A is disposed between the current collector and the first laminated film 22A. Thus, the first electrode lead 26A is connected to the positive electrode of the electrode body 40.

[0020] The negative electrode sheet 54 is formed, for example, by coating both sides of a sheet-like negative electrode current collector made of copper foil with a negative electrode active material. The negative electrode active material is a material capable of intercalating and deintercalating ions. As long as it is a lithium-ion secondary battery, it can be composed of carbon materials, fluoropolymers (such as polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, etc.), polyvinyl acetate, etc.

[0021] The separator 60 is an insulating layer that maintains the distance between the positive electrode 52 and the negative electrode 54 to prevent short circuits and retains the non-aqueous electrolyte. The separator 60 is, for example, made of a porous resin plate. In this embodiment, the battery cell 20 has a plurality of separators 60 cut into sheet shapes, and one separator 60 is disposed between the positive electrode 52 and the negative electrode 54.

[0022] The end of the negative electrode 54 in the width direction W is provided as a protruding end 54A that protrudes from the end of the separator in the width direction. This protruding end 54A is not coated with negative electrode active material, exposing the negative electrode current collector. The protruding end 54A, together with the protruding end 54A of another negative electrode 54, is integrated on the side of the first laminated film 22A, forming a current collector on the negative electrode side. In this embodiment, the protruding ends 54A of multiple negative electrode 54 are integrated on the side of the first laminated film 22A, forming a current collector on the negative electrode side, and a second electrode lead 26B is disposed between this current collector and the first laminated film 22A. Thus, the second electrode lead 26B is connected to the negative electrode of the electrode body 40.

[0023] Figure 3 This is a schematic top view showing a battery module 11 composed of multiple battery cells 20. Figure 3 The diagram shows the connection point between two series-connected unit groups 20DC, which consist of multiple battery cells 20.

[0024] like Figure 3As shown, the battery module 11 is formed by stacking multiple battery cells 20 in the thickness direction D within a module housing 16 that forms a box-shaped receiving space. At least a portion of the multiple battery cells 20 have two series-connected unit groups 20DC that are electrically connected in parallel.

[0025] The series connection unit group 20DC is composed of a plurality of battery cells 20 continuously connected via connection portions 70 that connect electrode leads 26 to each other. The series connection unit group 20DC is formed by corrugating and stacking the plurality of continuously connected battery cells 20 at the connection portions 70. Therefore, in the series connection unit group 20DC, the connection portions 70 of the electrode leads 26 are alternately arranged on one side and the other side in the width direction W. The number of battery cells 20 constituting the series connection unit group 20DC is not particularly limited, as long as there are two or more. In one example of this embodiment, the series connection unit group 20DC is composed of three continuously connected battery cells 20.

[0026] Each connecting portion 70 connects electrode leads with different polarities to each other. That is, it connects the first electrode lead 26A and the second electrode lead 26B. Therefore, multiple battery cells 20 constituting the series connection unit group 20DC are electrically connected in series via the connecting portions 70. The connecting portions 70 are, for example, welded portions such as spot welds.

[0027] Two series-connected unit groups 20DC are electrically connected in parallel via bus 30. Inside the module housing 16, a pair of electrode leads 26 with the same polarity are opposite each other in the stacking direction (thickness direction D). The pair of electrode leads 26 protrude from the two series-connected unit groups 20DC and are led to the bus 30 disposed on one side of the battery cell 20.

[0028] The busbar 30 is, for example, formed as a plate with the width direction W of the battery cell 20 as its thickness direction, and extends along the stacking direction (thickness direction D) of the battery cell 20. Inside the module housing 16, the busbar 30 is arranged on one side of the battery cell 20 in the width direction W. A pair of electrode leads 26 are inserted into slot-shaped through holes 32 that penetrate the busbar 30 in the thickness direction, and are welded to the surface of the busbar 30 with their protruding ends folded back towards the busbar 30. In this embodiment, a pair of first electrode leads 26A are overlapped on the surface of the busbar 30 and joined by simultaneous welding. Thus, two series-connected unit groups 20DC are electrically connected in parallel via the busbar 30.

[0029] As described above, the battery module 11 according to this embodiment has a plurality of battery cells 20 on which plate-shaped electrode bodies 40 constituting positive and negative electrodes are externally mounted with a laminated film 22, and electrode leads 26 protrude from one side and the other in the width direction W. Furthermore, in the battery module 11, the plurality of battery cells 20 are stacked in the thickness direction and housed in a module housing 16. Here, at least a portion of the plurality of battery cells 20 are continuously connected via a connecting portion 70 that connects the electrode leads 26 to each other. The connecting portion 70 is corrugated and stacked, thereby electrically connecting them. In this way, by directly connecting the electrode leads 26 to each other, the number of busbars 30 electrically connecting the battery cells 20 can be reduced, enabling miniaturization. This improves the housing efficiency of the module housing 16 in housing the plurality of battery cells 20.

[0030] Furthermore, in this embodiment, at least a portion of the plurality of battery cells 20 housed in the module housing 16 constitutes two series-connected unit groups 20DC, in which the plurality of battery cells 20 are electrically connected in series with each other via a connection portion 70. These two series-connected unit groups 20DC are then electrically connected in parallel via a busbar 30. Thus, by directly connecting the electrode leads 26 between the electrically series-connected battery cells 20, and performing corrugated folding and stacking, it becomes easier to identify the electrically directly connected battery cell groups and prevents confusion with the parts connected in parallel via the busbar 30. Therefore, the housing efficiency of the battery cells 20 can be improved by reducing the busbar 30, and the module assembly workability can also be improved.

[0031] The above description describes one embodiment of the present invention, but the present invention is not limited thereto. For example, in the above embodiment, the electrode leads 26 connected via the busbar 30 can be connected to each other by direct connection of the electrode leads 26, similar to the connection portion 70. That is, the busbar 30 can be omitted from the configuration of the above embodiment.

[0032] Furthermore, while the above embodiment employs a structure where electrode leads with different polarities are electrically connected to each other via the connection portion 70, it is not limited to this. It is also possible for electrode leads with the same polarity to be electrically connected to each other via the connection portion 70. That is, when multiple battery cells are continuously connected via the connection portion 70 to form a connection unit group, the connection portion 70 can directly connect adjacent battery cells 20 to each other, or it can connect them in parallel; these can be appropriately modified according to the design of the battery module.

Claims

1. A battery module comprising a plurality of battery cells for which plate-shaped electrode bodies constituting positive and negative electrodes are externally mounted by a laminated film, and electrode leads protrude from one and the other in the width direction, wherein the plurality of battery cells are stacked in the thickness direction and housed in a module housing, characterized in that, At least a portion of the plurality of battery cells are continuously connected via a connection portion that connects the electrode leads to each other, wherein the connection portion is corrugated and stacked, thereby electrically connecting them.

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