power storage device

Abstract

The utility model provides a kind of electric storage device, can be while inhibiting battery unit volume increase, make battery unit expansion not easily exert load to electrode terminal. Electric storage device has multiple battery units, busbar, first roller and second roller. Multiple battery units include the first battery unit and the second battery unit adjacent along the stacking direction. Busbar is arranged between the first electrode terminal in the pair of electrode terminals of the first battery unit and the second electrode terminal in the pair of electrode terminals of the second battery unit to carry out electrical connection. First roller is rotatably arranged on the first electrode terminal, and second roller is rotatably arranged on the second electrode terminal. Busbar is configured in the manner of contacting with first roller and second roller respectively, so as to be conducted respectively via first roller and second roller with the first electrode terminal and the second electrode terminal, and busbar is configured between the pair of electrode terminals of the first battery unit and the second battery unit respectively.

Description

Technical Field

[0001] This disclosure relates to an energy storage device having multiple battery cells. Background Technology

[0002] Patent document 1 discloses a battery module. A connecting bus has a pair of connecting portions and a bent portion that connect to the terminals of adjacent battery cells. The bent portion is formed between the pair of connecting portions and is capable of elongating and deforming in the parallel arrangement direction according to the expansion of the battery cells in the parallel arrangement direction.

[0003] Patent document 1: Japanese Patent Application Publication No. 2015-207442.

[0004] According to the structure described in Patent Document 1, the busbar (i.e., the connecting busbar) is directly connected to the electrode terminals of adjacent battery cells. More specifically, the busbar is fixed to each electrode terminal by fixing bolts. Therefore, even if the bent portion of the connecting busbar deforms due to the expansion of adjacent battery cells, a load will be applied to the electrode terminals fixing the busbar. To prevent the load on the electrode terminals from being easily applied, the best countermeasure is to implement a method that simultaneously suppresses the increase in battery cell volume while the busbar is in the assembled state. Utility Model Content

[0005] The energy storage device disclosed herein includes a plurality of battery cells, a busbar, a first roller, and a second roller. The plurality of battery cells includes a first battery cell and a second battery cell adjacent to each other in a stacking direction. The busbar is disposed between a first electrode terminal of a pair of electrode terminals of the first battery cell and a second electrode terminal of a pair of electrode terminals of the second battery cell, providing an electrical connection. The first roller is rotatably disposed on the first electrode terminal, and the second roller is rotatably disposed on the second electrode terminal. The busbar is configured to contact the first roller and the second roller respectively, thereby providing electrical connection to the first electrode terminal and the second electrode terminal respectively via the first roller and the second roller, and the busbar is disposed between each pair of electrode terminals of the first battery cell and the second battery cell.

[0006] According to the energy storage device disclosed herein, it is possible to suppress the increase in battery cell volume while making it less likely to generate load on the electrode terminals when the battery cell expands. Attached Figure Description

[0007] Figures 1A to 1G This is a diagram illustrating the configuration of the energy storage device according to Embodiment 1.

[0008] Figure 2A and Figure 2B This is a diagram used to illustrate the effect of the energy storage device involved in Embodiment 1.

[0009] Figures 3A to 3DThis is a diagram illustrating the configuration of the energy storage device according to Embodiment 2. Detailed Implementation

[0010] Figures 1A to 1G This is a diagram illustrating the configuration of the energy storage device 1 according to Embodiment 1. More specifically, Figure 1A This is a perspective view of energy storage device 1. Figure 1B A diagram showing the energy storage device 1 viewed from the stacking direction D1 of the battery cells 10. Figure 1C A diagram showing the energy storage device 1 viewed from the left-right direction D2 of the battery cell 10. Figures 1D to 1G Examples of various structures for roller 30.

[0011] The energy storage device 1 is mounted on a vehicle, for example, to supply power to the vehicle. The energy storage device 1 includes a plurality of battery cells 10 as secondary batteries and a plurality of busbars 20 electrically connecting adjacent battery cells 10. For example, the energy storage device 1 is mounted on a vehicle as a battery module or battery pack having a frame (not shown) that houses the plurality of battery cells 10. Alternatively, the energy storage device 1 may also be constructed using the vehicle chassis or body as the frame.

[0012] The energy storage device 1 includes multiple battery cells 10, with two or more battery cells 10 arranged in a stacking direction (i.e., front-to-back direction) D1. Alternatively, the multiple battery cells 10 may be modules comprising multiple such modules. Each battery cell 10 has, for example, a square shape. Each battery cell 10 has a pair of electrode terminals (i.e., a positive terminal and a negative terminal) 11. The pair of electrode terminals 11 protrudes outward from a common terminal mounting surface (e.g., the upper surface 12 of the battery cell 10). More specifically, the pair of electrode terminals 11 protrudes upward from the upper surface 12 in the height direction D3 of the battery cell 10 and is arranged in a left-to-right direction D2.

[0013] The configuration of the energy storage device 1 will now be described with respect to two battery cells 10 that are adjacent to each other in the stacking direction D1 among the plurality of battery cells 10 described above. Here, one of the two adjacent battery cells 10 will be referred to as "first battery cell 10A" and the other as "second battery cell 10B". In addition, in the example where the energy storage device 1 has a combination of multiple combinations of two battery cells 10 that are adjacent to each other in the stacking direction D1, the first battery cell 10A and the second battery cell 10B shown in the figure represent the configuration of multiple combinations of these two battery cells 10.

[0014] One of the pair of electrode terminals 11 of the first battery cell 10A is referred to as "first electrode terminal 11A", and one of the pair of electrode terminals 11 of the second battery cell 10B is referred to as "second electrode terminal 11B". Figure 1AOne of the multiple busbars 20 is shown in the figure. Figure 1A The bus 20 shown electrically connects the first electrode terminal 11A and the second electrode terminal 11B. More specifically, in the left-right direction D2, the first electrode terminal 11A and the second electrode terminal 11B are located on the same side. Furthermore, the bus 20 is configured to extend along the stacking direction D1.

[0015] Bus 20 is used, for example, to connect the first battery cell 10A and the second battery cell 10B in series. In this embodiment, if the first battery cell 10A is the positive terminal, then the second battery cell 10B is the negative terminal, and if the first battery cell 10A is the negative terminal, then the second battery cell 10B is the positive terminal. Alternatively, bus 20 can also be used to connect the first battery cell 10A and the second battery cell 10B in parallel. In this example, both the first battery cell 10A and the second battery cell 10B are either positive or negative terminals.

[0016] Battery cells can expand in the stacking direction due to years of degradation (for example, see below). Figure 2B Assuming the busbar is bolted to the battery cell terminals, the change in inter-cell distance due to the expansion of adjacent battery cells will load the terminals. Therefore, to reduce the load on the terminals, the best approach is to simultaneously suppress the increase in battery cell volume while the busbar is in the assembled state.

[0017] Therefore, the energy storage device 1 according to Embodiment 1 has the following configuration: The energy storage device 1 includes a roller 30 (i.e., roller 30A) rotatably disposed on the first electrode terminal 11A, and a roller 30 (i.e., roller 30B) rotatably disposed on the second electrode terminal 11B. More specifically, each roller 30 is integrated with its corresponding electrode terminal 11. It should be noted that, except for the electrode terminals 11 that are not connected to the electrode terminals 11 of adjacent battery cells 10 via the busbar 20, rollers 30 are also provided on the electrode terminals 11 of the battery cells 10 other than battery cells 10A and 10B in the plurality of battery cells 10 included in the energy storage device 1.

[0018] Bus 20 is configured to make perpendicular contact with rollers 30A (an example of the first roller) and 30B (an example of the second roller), respectively, and is connected to electrode terminals 11A and 11B via rollers 30A and 30B. Furthermore, as... Figure 1BAs shown, the busbar 20 is disposed between a pair of electrode terminals 11 in each of the battery cells 10A and 10B. In addition, in the example shown in the figure, the busbar 20 is configured in the height direction D3 to be within the height range of each of the electrode terminals 11A and 11B (in other words, it does not protrude above each electrode terminal 11A, 11B).

[0019] Next, specific construction examples (Examples 1 to 4) of the roller 30 will be described.

[0020] In the first case, such as Figure 1D As shown, the roller 30 is provided together with the rotating shaft 31 and a pair of support portions 32. The rotating shaft 31 rotatably supports the roller 30. In Embodiment 1, the rotating shaft 31 is parallel to the height direction D3 of the battery cell 10 and perpendicular to the upper surface 12 (i.e., the terminal mounting surface) of the battery cell 10. One end of the pair of support portions 32 is fixed to the electrode terminal 11, and the other end of the pair of support portions 32 is fixed to each end of the rotating shaft 31. In the first example, the roller 30 is positioned at the middle in the height direction D3.

[0021] In the second case, such as Figure 1E As shown, electrode terminal 11 is rotatably supported by a rotation axis 33 concentric with it. Similar to the first example, in this example, the rotation axis 33 is also parallel to the height direction D3 and perpendicular to the upper surface 12. More specifically, in the second example, from... Figure 1E As shown in the cross-sectional view on the right, for example, the rotating shaft 33 has a large-diameter portion 34 supporting the roller 30 and a pair of small-diameter portions 35 located on both sides of the large-diameter portion 34. The electrode terminal 11 is formed, for example, by dividing it into two cylindrical parts having the same diameter as the large-diameter portion 34, covering the pair of small-diameter portions 35. In addition, in the second example, the roller 30 is also positioned in the middle in the height direction D3.

[0022] like Figure 1F As shown, the third example has the same configuration as the first example, except that the position of the roller 30 in the height direction D3 is different. In this example, the roller 30 is configured to have the same height as the electrode terminal 11.

[0023] like Figure 1G As shown, the fourth example has the same configuration as the second example, except that the position of the roller 30 in the height direction D3 is different. In this example, the roller 30 is configured to have the same height as the electrode terminal 11.

[0024] Rollers 30 are located between the first electrode terminal 11A and the second electrode terminal 11B and the bus 20, respectively. Therefore, rollers 30 are required to be conductive with the first electrode terminal 11A, the second electrode terminal 11B, and the bus 20, respectively.

[0025] Therefore, various metals (e.g., iron) can be listed as materials for the roller 30, as general conductive materials. More specifically, considering the effects of long-term vehicle loading or vibration, it is preferable to perform electroplating treatment on the roller 30 to prevent oxidation or rust. Alternatively, the roller 30 is preferably formed of a material that is not prone to rust or other oxidation-induced changes. In addition, to maintain conductivity even after wear is reduced due to wear, the roller 30 may be formed of, for example, a conductive resin material. Furthermore, the components between the roller 30 and the electrode terminals 11, namely the rotating shaft 31 (or rotating shaft 33) and the pair of support portions 32, are also formed of conductive materials such as metal.

[0026] In addition, such as Figures 1A to 1C As shown, the busbar 20 contacts battery cells 10A and 10B only at the roller 30. Furthermore, in Embodiment 1, the busbar 20, having an elongated plate shape, is arranged parallel to each electrode terminal 11A, 11B. More specifically, the short side of the busbar 20 is perpendicular to the upper surface 12 of each battery cell 10, while its long side is parallel to the stacking direction D1. This busbar 20 is supported by the frame of the energy storage device 1 (e.g., module housing, battery pack housing). Furthermore, regarding the stacking direction D1, the busbar 20 has the characteristic that even after the change in the inter-cell distance DC caused by the expansion of the battery cells 10 (see below) Figure 2B The length that can maintain contact with each roller 30.

[0027] In addition, such as Figure 1B In the illustrated case where two busbars 20 are connected to a pair of electrode terminals 11 of a single battery cell 10 via rollers 30, these two busbars 20 can also be supported on the frame via an insulator 40 fixed to the frame. The insulator 40 has the following function: To more reliably maintain contact between each busbar 20 and each roller 30, the insulator 40, as... Figure 1B The insulator 40 is arranged between two busbars 20 corresponding to a pair of electrode terminals 11 of the battery cell 10. More specifically, the insulator 40 may have a shape consistent with the gap between the two busbars 20, or it may be formed using a rubber-like material with a width slightly larger than the gap between the two busbars 20. In the latter example, the two busbars 20 are pressed against one side of each electrode terminal 11. This allows for better contact between each busbar 20 and each battery cell 10. Furthermore, to suppress the increase in the volume of the battery cell 10, the insulator 40 is preferably as follows... Figure 1B The structure is formed in a manner that does not protrude upwards in the height direction D3, or where the protrusion is minimized. Alternatively, for example, a metallic spring can be used instead of an insulator such as rubber 40, and an insulator can be sandwiched between the spring and each busbar 20.

[0028] Similarly, like the roller 30, the busbar 20 is also made of metal. Furthermore, the materials of the roller 30 and the busbar 20 at the contact portion can be the same or different. However, for safety reasons, the portions of the busbar 20 other than the contact portion with the roller 30 can also be made of insulating material.

[0029] Furthermore, the busbar 20 is a component that contacts the roller 30 and causes the roller 30 to roll, and therefore has a plate-like shape with a smooth surface. However, the busbar 20 may also have guides (e.g., in the vertical direction, i.e., the height direction D3) on the contact surface with the roller 30 to limit the position of the roller 30 in the vertical direction (i.e., the height direction D3). Figure 1B (as shown in the groove 21). Furthermore, the groove 21 is preferably formed to have a concave cross-sectional shape when viewed from the stacking direction D1, supporting the roller 30 from above and below (in other words, in the height direction D3). Additionally, the groove 21 is formed to extend along the length direction of the busbar 20 (i.e., the stacking direction D1).

[0030] Furthermore, the plurality of battery cells 10 included in the energy storage device 1 may also be configured such that adjacent battery cells 10 in the stacking direction D1 have a plate-shaped insulator between them. Moreover, in this embodiment, the aforementioned insulator 40 may not be provided (see [link to documentation]). Figure 1B Instead, a plate-shaped insulator is used, which can be formed to extend to the same position as the aforementioned insulator 40, so as to maintain contact between each busbar 20 and roller 30 opposite to a pair of electrode terminals 11 in each battery cell.

[0031] Figure 2A and Figure 2B This is a diagram used to illustrate the effect of the energy storage device 1 according to Embodiment 1. More specifically, Figure 2A The energy storage device 1 represents the initial stage. Figure 2B The energy storage device 1 represents the expansion due to deterioration. (Comparison) Figure 2A and Figure 2B It is known that when each battery cell 10A and 10B expands due to deterioration, the distance DC between the cells gradually increases due to the expansion of each battery cell 10A and 10B. Furthermore, in a battery module in which a predetermined number of battery cells 10 are arranged along the stacking direction D1, especially in the battery cells 10 that are adjacent to each other near the center of the battery module, the distance DC between the cells gradually increases.

[0032] According to the above-described energy storage device 1, among the busbar 20 and each battery cell 10A, 10B, only each battery cell 10A, 10B has a degree of freedom in the stacking direction D1, thereby enabling conduction between battery cells 10A and 10B. Therefore, according to this energy storage device 1, when the inter-cell distance DC increases, the movement of each battery cell 10A, 10B is not hindered by the busbar 20. That is, while maintaining the conductivity between the busbar 20 and each electrode terminal 11 by the roller 30, deformation of each battery cell 10 and variation of the inter-cell distance DC are allowed. Furthermore, the busbar 20 is disposed between a pair of electrode terminals 11 in each of the battery cells 10A and 10B. Therefore, according to this energy storage device 1, while suppressing the increase in volume of each battery cell 10, it is not easy to apply a load to the electrode terminals 11 when the battery cell 10 expands.

[0033] Figures 3A to 3D This is a diagram illustrating the configuration of the energy storage device 2 according to Embodiment 2. More specifically, Figure 3A This is a perspective view of energy storage device 2. Figure 3B This is an enlarged view of roller 36 and electrode terminal 11. Figure 3C and Figure 3D Various specific examples of the configuration around busbar 22 or 23.

[0034] The configuration of the energy storage device 2 is the same as that of the energy storage device 1 in Embodiment 1, except that the rotation direction of the roller is different, and consequently the bus configuration is also different. Specifically, in the energy storage device 1, the rotation axis 31 (or rotation axis 33) of the roller 30 is parallel to the height direction D3. In contrast, in the energy storage device 2, as... Figures 3A to 3D As shown, the rotation axis 37 of the roller 36 is parallel to the left-right direction D2 (in other words, the direction in which a pair of electrode terminals 11 in each battery cell 10 are opposite to each other). In the following description, the roller 36 provided at the first electrode terminal 11A is referred to as roller 36A (i.e., an example of the first roller), and the roller 36 provided at the second electrode terminal 11B is referred to as roller 36B (i.e., an example of the second roller).

[0035] Because the rollers 36 rotate in different directions, the busbar 22 is configured as follows. Here, the busbar 22 used to connect the first battery unit 10A and the second battery unit 10B (see...) Figure 3A Taking one example, the busbar 22 is disposed between rollers 36A and 36B and the upper surface 12 of each battery cell 10A, 10B. The busbar 22 has an elongated plate shape and is disposed parallel to the upper surface 12 of each battery cell 10. More specifically, similar to the busbar 20, the long side of the busbar 22 is parallel to the stacking direction D1.

[0036] like Figure 3C As shown in the diagram on the right, the upper surfaces of the busbar 22, arranged in the aforementioned direction, contact the rollers 36 (i.e., rollers 36A and 36B), respectively. The lower surface of the busbar 22 is supported by the upper surfaces 12 of each battery cell 10 via an elastic insulator 41. In other words, the busbar 22 is held together by the upper surfaces 12 and the rollers 36 using the elasticity of the insulator 41 between it and the upper surfaces 12 of each battery cell 10. Further explanation: before assembly, the length of the insulator 41 pressed between the busbar 22 and the upper surfaces 12 of each battery cell 10 from the upper surface of the busbar 22 to the lower surface of the insulator 41 is set to be greater than the distance between the rollers 36 and the upper surfaces 12, i.e., it has a height H1 (see Figure 1). Figure 3C (See the diagram on the left). After busbar 22 is assembled, the height of insulator 41 is reduced to height H2 (see diagram on the left). Figure 3C (See the diagram on the right). Thus, by means of the elasticity of the insulator 41, the position of the busbar 22 in the height direction D3 is fixed while maintaining contact between the busbar 22 and each roller 36.

[0037] In addition, such as Figure 3A As shown, similar to the busbar 20 in Embodiment 1, the busbar 22 is also disposed between a pair of electrode terminals 11 of each of the battery cells 10A and 10B. Furthermore, the busbar 22 is also disposed within the height range of the electrode terminals 11 (i.e., electrode terminals 11A and 11B) in the height direction D3 (see [reference]). Figure 3C ).

[0038] Additionally, the energy storage device 2 in Embodiment 2 may also include... Figure 3D The busbar 23 shown is used instead of busbar 22. The busbar 23 differs from busbar 22 in that it has a groove 24 on its upper surface that contacts each roller 36. The groove 24 is an example of a guide for limiting the position of the roller 36 in the left-right direction D2, and is formed to extend along the long side direction (i.e., the stacking direction D1) of the busbar 23.

[0039] Therefore, the energy storage device 2 according to embodiment 2 can also suppress the increase in volume of each battery cell 10 while making it less likely for the battery cell 10 to exert a load on the electrode terminals 11 when it expands.

Claims

1. An energy storage device, characterized in that, have: Multiple battery cells, including a first battery cell and a second battery cell that are adjacent to each other along the stacking direction; Busbar for electrically connecting the first electrode terminal of a pair of electrode terminals of the first battery cell and the second electrode terminal of a pair of electrode terminals of the second battery cell. The first roller is rotatably mounted on the first electrode terminal; and The second roller is rotatably mounted on the second electrode terminal. The bus is configured to contact the first roller and the second roller respectively, thereby conducting to the first electrode terminal and the second electrode terminal respectively via the first roller and the second roller, and the bus is disposed between the pair of electrode terminals of the first battery cell and the second battery cell respectively.

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