Power storage device

Abstract

To provide a power storage device capable of providing more electrode terminals in the range of connecting wires.SOLUTION: A power storage device according to the present disclosure includes a laminate of a plurality of power storage elements including electrode terminals 2, a sealing body 4 that incorporates the electrode terminals 2 and the laminate, and a flexible wiring board 5 that electrically connects the electrode terminals 2 and is extracted from an extraction part W of the sealing body 4 to the outside of the sealing body 4. The extraction part W is formed facing a surface having the electrode terminal 2 and using a lamination direction of the power storage elements as a short-side direction. The electrode terminal 2 is arranged tilted from the lamination direction. The flexible wiring board 5 includes a first wiring part 51 disposed along an arrangement direction of the electrode terminals 2 so as to electrically connect the electrode terminals 2, a second wiring part 52 extracted from the surface having the electrode terminal 2 to the outside of the sealing body 4 along a vertical direction, and a third wiring part 53 connecting the first wiring part 51 and the second wiring part 52 while curving.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electricity storage device. [Background technology]

[0002] In the wiring method for electrode terminals of battery packs, cable wiring is increasingly being replaced with flexible printed circuit board wiring. By replacing cable wiring with flexible printed circuit board wiring, space can be saved and the burden of wiring connection work can be reduced. Furthermore, flexible printed circuit boards are thin and easily bendable, making them suitable for wiring in narrow spaces and connection to curved surfaces. Therefore, wiring using flexible printed circuit boards offers greater freedom in wiring than cable wiring. Patent Document 1 discloses a battery pack wired using a flexible printed circuit board. In Patent Document 1, the flexible printed circuit board is connected perpendicular to the battery pack, which reduces the area required for connecting the wiring on the battery pack surface compared to a structure in which the flexible printed circuit board is connected parallel to the battery pack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-38064 Summary of the Invention [Problem to be solved by the invention]

[0004] As battery packs (hereinafter referred to as energy storage devices) continue to become smaller, the area for connecting wiring on the surface of the energy storage module that constitutes the energy storage device becomes even more limited. Therefore, for example, a method of arranging electrode terminals at an angle from the stacking direction of the energy storage elements can be considered. This method allows many electrodes to be provided in a limited area on the surface of the energy storage module. However, when a flexible printed circuit board is wired to energy storage elements that are arranged at an angle, the flexible printed circuit board becomes twisted, generating torsional stress. Flexible printed circuit boards are sufficiently strong against bending stress, but are not strong enough against torsional stress. Therefore, when flexible printed circuit boards are wired in a twisted state, there is a risk of breakage or fracture.

[0005] The present invention has been made to solve such problems, and provides an electricity storage device that can be provided with a larger number of electrode terminals while preventing damage to wiring. [Means for solving the problem]

[0006] The energy storage device according to the present disclosure is an energy storage device comprising: a stack of a plurality of energy storage elements each having an electrode terminal; a sealing body containing the electrode terminals and the stack; and a flexible wiring board electrically connecting the electrode terminals and drawn out to the outside of the sealing body from a drawing portion formed in the sealing body, wherein the drawing portion is arranged opposite to the surface of the energy storage elements that has the electrode terminals and is formed with the stacking direction of the energy storage elements as its short side direction, the electrode terminals are arranged at an angle with respect to the stacking direction of the energy storage elements, and the flexible wiring board comprises: a first wiring portion arranged along the arrangement direction of the electrode terminals so as to electrically connect the electrode terminals of the plurality of energy storage elements; a second wiring portion drawn out to the outside of the sealing body from the drawing portion along a direction perpendicular to the surface of the energy storage elements that has the electrode terminals; and a third wiring portion that curves to connect the first wiring portion and the second wiring portion.

[0007] Preferably, the storage battery further comprises a connector for accommodating the electrode terminals of the plurality of energy storage elements, the connector being formed with its short side aligned with the stacking direction of the energy storage elements.

[0008] The sealing body is preferably a laminate film.

[0009] Furthermore, it is preferable that the second wiring portion is fixed by the sealing body at the lead-out portion.

[0010] It is also preferable that a plurality of flexible wiring boards are provided, one of which is drawn out from one end of the connector in a direction perpendicular to the stacking direction of the energy storage elements, and the other is drawn out from the other end. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an electricity storage device in which more electrode terminals can be provided in the area where wiring is connected. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a side view of the electricity storage device according to the first embodiment, with the sealing body removed. [Figure 2] FIG. 2 is a plan view of the electricity storage device according to the first embodiment, with the sealing body removed. [Figure 3] 3 is a cross-sectional view taken along line III-III of the electricity storage device shown in FIG. 1 in a state where a sealing body is provided. [Figure 4] FIG. 4 is a side view of the electricity storage device in the comparative example with the sealing body removed. [Figure 5] 5 is a VV cross-sectional view of the power storage device shown in FIG. 4 in a state where a sealing body is provided. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiment 1 The electricity storage device according to the first embodiment will be described below with reference to the drawings.

[0014] <Configuration of the power storage device> First, the configuration of the electricity storage device according to the first embodiment will be described with reference to Figs. 1 to 3. Fig. 1 is a side view of the electricity storage device according to the first embodiment with the sealing body removed. Fig. 2 is a plan view of the electricity storage device according to the first embodiment with the sealing body removed. Fig. 3 is a cross-sectional view taken along III-III of the electricity storage device shown in Fig. 1 with the sealing body provided.

[0015] As shown in FIGS. 1 to 3, the energy storage device 100 includes an energy storage module 1, electrode terminals 2, a connector 3, a sealing body 4, and a flexible wiring board 5.

[0016] The energy storage module 1 includes a stack of multiple energy storage elements. Each energy storage element is formed in a substantially rectangular parallelepiped shape and has substantially the same size. In the following description, an xyz three-dimensional Cartesian coordinate system is used where appropriate. The x, y, and z directions are parallel to the sides of the rectangular parallelepiped energy storage elements. In the energy storage module 1, the energy storage elements are stacked in one direction (the y direction). The energy storage module 1 is, for example, a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery.

[0017] The electrode terminals 2 are provided on the energy storage element and are electrically connected to other electrode terminals 2 via a flexible wiring substrate 5. As shown in FIG. 1, the electrode terminals 2 are arranged at an angle with respect to the stacking direction (y direction) of the energy storage element. In an xy plan view, the multiple electrode terminals 2 are arranged along a straight line inclined with respect to the x direction. The positions of the electrode terminals 2 of two adjacent energy storage elements are shifted in the y direction. By arranging the electrode terminals 2 at an angle with respect to the stacking direction (y direction), it is possible to provide more electrode terminals 2 in a limited range on the surface of the energy storage element on which the electrode terminals 2 are provided. Here, the electrode terminals 2 are provided on the front surface (+z side surface) of the energy storage element.

[0018] The connector 3 is provided on the surface of the energy storage element that has the electrode terminals 2, and accommodates the electrode terminals 2. As shown in Fig. 1, the connector 3 is formed with its short side aligned with the stacking direction (y direction) of the energy storage elements and its long side aligned with the direction (x direction) perpendicular to the stacking direction (y direction) of the energy storage elements. Therefore, the connector 3 is installed at an angle with respect to the arrangement direction of the electrode terminals 2.

[0019] As shown in FIG. 3 , the sealing body 4 contains the energy storage module 1, the electrode terminals 2, and the connector 3, and is sealed with the flexible wiring board 5 extended to the outside of the sealing body 4. The sealing body 4 is made of a material such as metal or synthetic resin. The sealing body 4 in the first embodiment is made of a laminate film. Here, the laminate film is a film having a metal layer and a sealant layer. Examples of materials used for the metal layer include aluminum and stainless steel. Examples of materials used for the sealant layer include thermoplastic resins such as polypropylene, polyethylene, polystyrene, and polyvinyl chloride.

[0020] The sealing body 4 has an extraction portion W for extracting the flexible wiring board 5 to the outside of the sealing body 4. As shown in FIG. 3, the extraction portion W is arranged in the sealing body 4 so as to face the surface of the energy storage element on which the electrode terminals 2 are provided. As shown in FIG. 1, the extraction portion W is formed with its short side aligned with the stacking direction (y direction) of the energy storage element and its long side aligned with the direction (x direction) perpendicular to the stacking direction (y direction) of the energy storage element. Therefore, the extraction portion W is formed at an angle with respect to the arrangement direction of the electrode terminals 2.

[0021] The sealing body 4 is sealed in a state in which the flexible wiring board 5 is drawn out from the drawing portion W to the outside of the sealing body 4. In other words, the sealing body 4 is bonded at the drawing portion W to seal the inside. In the first embodiment, LamiSeal sealing is used as the bonding method for the sealing body 4, but this is not limiting. For example, a method of welding the sealant material layers of the sealing body 4 together (e.g., hot plate welding, ultrasonic welding, vibration welding, or laser welding), a method of bonding with an adhesive, or the like can be used.

[0022] The flexible wiring board 5 electrically connects the electrode terminals 2 to each other and is drawn out from the drawing portion W to the outside of the sealing body 4. The flexible wiring board 5 is a flexible wiring. In the first embodiment, a flexible printed circuit board is used as the flexible wiring board 5, but the present invention is not limited to this and may be, for example, a flexible flat cable. The flexible wiring board 5 has wiring formed by printed wiring technology on the surface of a flexible insulating film.

[0023] <Structure of flexible wiring board> Next, a description will be given of the configuration of the flexible wiring board 5 of the power storage device 100 according to the present embodiment 1. The flexible wiring board 5 according to the present embodiment 1 includes a first wiring portion 51, a second wiring portion 52, and a third wiring portion 53.

[0024] 1, the first wiring portion 51 is arranged along the arrangement direction of the electrode terminals 2 so as to electrically connect the electrode terminals 2 of the plurality of energy storage elements. The first wiring portion 51 is connected to the electrode terminals 2 inside the connector 3.

[0025] 3, the second wiring portion 52 is drawn out from the drawing portion W to the outside of the sealing body 4 in a direction perpendicular to the surface of the energy storage element on which the electrode terminals 2 are provided (z direction). The second wiring portion 52 is fixed by the sealing body 4 at the drawing portion W.

[0026] 1 , the third wiring portion 53 connects the first wiring portion 51 and the second wiring portion 52 while being curved. It is preferable that the third wiring portion 53 connects the first wiring portion 51 and the second wiring portion 52 while being curved on an extension line of the first wiring portion 51. By being curved on an extension line of the first wiring portion 51, it is possible to suppress the occurrence of bending stress in the third wiring portion 53.

[0027] When the energy storage device 100 includes a plurality of flexible wiring boards 5, in the first embodiment, lamination sealing is used to seal the sealing body 4 at the drawing-out portion W, and therefore the second wiring parts 52 are preferably arranged in a direction (x direction) perpendicular to the stacking direction of the energy storage elements. By arranging the second wiring parts 52 in a direction (x direction) perpendicular to the stacking direction of the energy storage elements, the sealing body 4 can be suitably sealed at the drawing-out portion W, and the sealing performance of the inside of the sealing body 4 can be ensured. Furthermore, the energy storage device 100 may have a structure in which one flexible wiring board 5 is drawn out to the outside of the connector 3 from one end side in the direction (x direction) perpendicular to the stacking direction of the energy storage elements, and another flexible wiring board 5 is drawn out from the other end side.

[0028] For example, three flexible wiring boards 5 are provided in FIG. 1 . The three flexible wiring boards 5 are spaced apart in the y direction. The first wiring portions 51 of the three flexible wiring boards 5 are arranged parallel to one another in the xy plane view. The flexible wiring board 5 on the +y side is drawn out from the end on the -x side. Therefore, in the flexible wiring board 5 on the +y side, the third wiring portion 53 is arranged on the -x side of the first wiring portion 51. The flexible wiring board 5 on the -y side is drawn out from the end on the +x side. Therefore, in the flexible wiring board 5 on the -y side, the third wiring portion 53 is arranged on the +x side of the first wiring portion 51.

[0029] The flexible wiring board 5 in the middle in the y direction is drawn out from the center in the x direction to the outside. The flexible wiring board 5 drawn out from the center in the x direction to the outside does not have a third wiring portion 53. The flexible wiring board 5 drawn out from the center in the x direction to the outside has a second wiring portion 52 in the center in the x direction. Of course, the drawing position of the flexible wiring board 5 is not particularly limited.

[0030] <Effects of flexible wiring board configuration> Here, before describing the effects of the configuration of flexible wiring board 5 in present embodiment 1, the configuration of flexible wiring board 5 in a comparative example will be described. After that, the effects of the configuration of flexible wiring board 5 in present embodiment 1 will be described in comparison with the comparative example.

[0031] Fig. 4 is a plan view of an energy storage device in a comparative example with the sealing body removed. Fig. 5 is a VV cross-sectional view of the energy storage device shown in Fig. 4 with the sealing body provided. Energy storage device 100 of the comparative example shown in Figs. 4 and 5 differs from energy storage device 100 of the present embodiment 1 shown in Figs. 1 to 3 in the configuration of flexible wiring board 5. The configuration of energy storage device 100 of the comparative example is the same as the configuration of energy storage device 100 of the present embodiment 1 shown in Figs. 1 to 3, except for the configuration of flexible wiring board 5.

[0032] The flexible wiring board 5 of the comparative example includes the same first wiring portion 51 and second wiring portion 52 as the flexible wiring board 5 of the first embodiment, and further includes a third wiring portion T. As shown in FIGS. 4 and 5, the third wiring portion T connects the first wiring portion 51 and the second wiring portion 52 while being twisted.

[0033] In the energy storage device 100, the electrode terminals 2 are arranged at an angle with respect to the stacking direction (y direction) in order to provide a larger number of electrode terminals 2. Therefore, the lead-out portion W is formed at an angle with respect to the arrangement direction of the electrode terminals 2. Therefore, if an attempt is made to directly lead the first wiring portion 51 from the end portion thereof to the outside of the sealing body 4 through the lead-out portion W, the configuration of the flexible wiring board 5 in the comparative example will result. In other words, as shown in FIGS. 4 and 5, the third wiring portion T is arranged to connect the first wiring portion 51 and the second wiring portion 52 while twisting.

[0034] Here, we will explain the structure of flexible printed circuit boards against stress. Flexible printed circuit boards are flexible, so their structure is strong enough to withstand bending stress. On the other hand, flexible printed circuit boards are not as strong against torsional stress as they are against bending stress. Therefore, when a flexible printed circuit board is twisted, it is more likely to break or fracture than when it is bent.

[0035] As shown in Fig. 1, the third wiring portion 53 in the first embodiment connects the first wiring portion 51 and the second wiring portion 52 while curving without twisting. On the other hand, the third wiring portion T in the comparative example connects the first wiring portion 51 and the second wiring portion 52 while twisting, as shown in Figs. 4 and 5. That is, bending stress is mainly generated in the third wiring portion 53 in the first embodiment, and torsional stress is mainly generated in the third wiring portion T in the comparative example.

[0036] The first wiring portion 51 and the second wiring portion 52, which are common to the first embodiment and the comparative example, are arranged so as not to generate torsional stress. Therefore, the configuration of the flexible wiring board 5 in the comparative example generates torsional stress, but the configuration of the flexible wiring board 5 in the first embodiment does not generate torsional stress. Therefore, by using the configuration of the flexible wiring board 5 in the first embodiment, it is possible to realize an electricity storage device that can be provided with more electrode terminals while preventing damage to the wiring within a limited range.

[0037] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0038] 1. Energy storage module 2 electrode terminals 3 Connectors 4 Encapsulation body 5 Flexible wiring board 51 First wiring section 52 Second wiring section 53 Third wiring section 100 Electricity storage device W Drawer section

Claims

1. a stack of a plurality of energy storage elements each having an electrode terminal; a sealing body that contains the electrode terminal and the laminate; a flexible wiring board electrically connecting the electrode terminals and drawn out from a drawing portion formed in the sealing body to an outside of the sealing body, the lead-out portion is disposed opposite to a surface of the energy storage element that is provided with the electrode terminal, and is formed with a short side direction that coincides with a stacking direction of the energy storage element, the electrode terminals are arranged at an angle with respect to the stacking direction of the energy storage elements, The flexible wiring board is a first wiring portion arranged along the arrangement direction of the electrode terminals so as to electrically connect the electrode terminals of the plurality of energy storage elements; a second wiring portion that is drawn from a drawing portion to the outside of the sealing body along a direction perpendicular to the surface of the energy storage element that includes the electrode terminals; a third wiring portion that connects the first wiring portion and the second wiring portion while bending, Energy storage device.

2. a connector that accommodates the electrode terminals of the plurality of power storage elements; The connector is formed with the stacking direction of the energy storage elements as its short side direction. The power storage device according to claim 1 .

3. The sealing body is a laminate film. The power storage device according to claim 2 .

4. the second wiring portion is fixed by the sealing body at the lead-out portion; The power storage device according to claim 3 .

5. A plurality of the flexible wiring boards are provided, one of the flexible wiring boards is drawn out to the outside of the connector from one end side in a direction perpendicular to the stacking direction of the energy storage elements, and the other of the flexible wiring boards is drawn out to the outside of the connector from the other end side; The power storage device according to claim 4.

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