Power storage module

Abstract

The present invention relates to a storage module. A cover component (700) is arranged on a resin plate (400) and covers a flexible printed substrate (500). The resin plate (400) has an opening (420) at a position where a thermistor element (550) and a storage unit (100) contact each other. The flexible printed substrate (500) has an extension piece (560) extending to the opening (420) of the resin plate (400), and a root (590) adjacent to the extension piece (560) and wider than the extension piece (560). The thermistor element (550) is arranged on the extension piece (560). The cover component (700) has a protrusion (730) that protrudes toward the resin plate (400) and bends the extension piece (560) to press the thermistor element (550) against the storage unit (100). The root (590) is fixed to the resin plate (400).

Description

Technical Field

[0001] The present technology relates to a power storage module. Background Art

[0002] As an existing document that discloses the structure of an electricity storage module, there is Japanese Patent Publication No. 2019-135687. The electricity storage module described in Japanese Patent Publication No. 2019-135687 includes a plurality of electricity storage units, a smoke exhaust duct, a flexible printed circuit board, and a cover. The plurality of electricity storage units are interconnected by bus bars. The smoke exhaust duct covers the plurality of electricity storage units and includes a protrusion protruding from the surface of the smoke exhaust duct. The flexible printed circuit board includes: a snap-fitting portion, which is arranged on the surface of the smoke exhaust duct and snaps into the protrusion; and a branch portion, which is located next to the snap-fitting portion and is connected to the bus bar. The cover is provided on the smoke exhaust duct and has a pressing piece that can press the flexible printed circuit board. The flexible printed circuit board is pressed toward the smoke exhaust duct by the pressing piece and is fixed in position along the smoke exhaust duct when the protrusion is snapped into the snap-fitting portion. Summary of the Invention

[0003] Sometimes a thermistor is used to detect the temperature of an electric storage cell. In this case, the detection accuracy of the thermistor may be reduced due to a positional deviation of the thermistor relative to the electric storage cell.

[0004] The present technology has been developed to solve the above-mentioned problems, and an object thereof is to provide a power storage module capable of improving the positioning accuracy of a thermistor element relative to a power storage cell.

[0005] The storage module based on the present technology includes a stack, a resin plate, a flexible printed circuit board, a thermistor element, and a cover component. The stack has a plurality of storage cells stacked thereon. The resin plate is placed on the stack. The flexible printed circuit board is placed on the resin plate and has a circuit electrically connected to the plurality of storage cells. The thermistor element is arranged on the circuit and contacts one of the plurality of storage cells to detect the temperature of the storage cell. The cover component is placed on the resin plate and covers the flexible printed circuit board. The resin plate has an opening at a position where the thermistor element and the storage cell contact each other. The flexible printed circuit board has an extension piece extending to the opening of the resin plate, and a root portion adjacent to the extension piece and wider than the extension piece. The thermistor element is arranged on the extension piece. The cover component has a protrusion that protrudes toward the resin plate side, bends the extension piece, and presses the thermistor element against the storage cell. The root portion is fixed to the resin plate.

[0006] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a diagram showing the basic structure of a battery pack.

[0008] Figure 2 Yes Figure 1 Diagram of the battery cells and end plates in the battery pack shown.

[0009] Figure 3 Yes Figure 1 Diagram of battery cells in a battery pack shown.

[0010] Figure 4 This is a perspective view showing a state where a wiring module is installed on a battery pack.

[0011] Figure 5 This is a schematic top view of a wiring module mounted on a battery pack.

[0012] Figure 6 This is a perspective view showing the vicinity of a thermistor element.

[0013] Figure 7 This is a schematic plan view of a cover member covering the wiring module.

[0014] Figure 8 This is a cross-sectional view of the area surrounding the thermistor element in the wiring module.

[0015] Figure 9 It is a cross-sectional view showing the vicinity of the base portion of the wiring module in a state where the cover member is mounted.

[0016] Figure 10 It is a cross-sectional view near the root of the first modification.

[0017] Figure 11 It is a cross-sectional view near the root of the second modification. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present technology will be described. It should be noted that the same reference numerals are given to the same or corresponding parts, and their description may not be repeated.

[0019] It should be noted that, in the embodiments described below, when numbers, amounts, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to such numbers, amounts, etc. In addition, in the embodiments described below, each component is not necessarily essential to the present technology unless otherwise specified.

[0020] It should be noted that in this specification, the terms "having," "including," and "having" are open-ended. That is, when a certain structure is included, other structures other than that structure may also be included, or not included. Furthermore, this technology is not limited to technologies that must achieve all the effects described in this embodiment.

[0021] In this specification, the term "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries. In this specification, the term "electrode" may refer to both positive and negative electrodes. Furthermore, the term "electrode plate" may refer to both positive and negative plates.

[0022] In this specification, the term "electricity storage unit" or "electricity storage module" is not limited to a battery cell or a battery module, but may include a capacitor cell or a capacitor module.

[0023] Figure 1 1 is a diagram showing the basic structure of the battery pack 1 . Figure 2 1 is a diagram showing a battery cell 100 and an end plate 200 included in the battery pack 1 .

[0024] like Figure 1 、 Figure 2 As shown, a battery pack 1 as an example of a “power storage module” includes battery cells 100 , end plates 200 , and restraint members 300 .

[0025] The multiple battery cells 100 are arranged in a row along the Y-axis (arrangement direction). This forms a stack of battery cells 100. Separators (not shown) are interposed between the multiple battery cells 100. The multiple battery cells 100 sandwiched between the two end plates 200 are pressed by the end plates 200 and constrained between the two end plates 200.

[0026] The end plates 200 are disposed at both ends of the battery pack 1 in the Y-axis direction. The end plates 200 are fixed to a base such as a case that houses the battery pack 1. Step portions 210 are formed at both ends of the end plates 200 in the X-axis direction.

[0027] The restraining member 300 connects the two end plates 200 to each other. The restraining member 300 is attached to the step portions 210 formed on the two end plates 200, respectively.

[0028] While a compressive force in the Y-axis direction is applied to the stack of battery cells 100 and end plates 200, the restraining member 300 is engaged with the end plates 200. The compressive force is then released, causing a tensile force to act on the restraining member 300 connecting the two end plates 200. As a reaction to this, the restraining member 300 presses the two end plates 200 toward each other.

[0029] The restraining member 300 includes a first member 310 and a second member 320. The first member 310 and the second member 320 are joined to each other by, for example, butt welding. The front end surface of the folded-back second member 320 abuts against the step portion 210 of the end plate 200 in the Y-axis direction.

[0030] Figure 3 FIG is a diagram showing a battery cell 100 in a battery pack 1. Figure 3 As shown, the battery cell 100 includes an electrode terminal 110 , a frame 120 , and a gas discharge valve 130 .

[0031] The electrode terminal 110 includes a positive terminal 111 and a negative terminal 112. The electrode terminal 110 is formed on the frame 120. The frame 120 is formed in a substantially rectangular parallelepiped shape. The frame 120 houses an electrode assembly (not shown) and an electrolyte. The gas discharge valve 130 ruptures when the pressure within the frame 120 exceeds a predetermined value. This allows the gas within the frame 120 to be discharged outside the frame 120.

[0032] Figure 4 1 is a perspective view showing a state where a wiring module is provided on the battery pack 1. Figure 4 As shown, a plate member 400 is placed on the battery pack 1, and a flexible printed circuit board 500 is provided on the plate member 400. The flexible printed circuit board 500 can be electrically connected to an external device via a connector 600. A cover member 700 is provided on the plate member 400 to cover the flexible printed circuit board 500.

[0033] Figure 5 1 is a schematic top view of a wiring module mounted on the battery pack 1. Figure 5 As shown, the wiring module includes a board member 400 , a flexible printed substrate 500 , and a connector 600 .

[0034] Plate member 400 (busbar plate) is a resin plate with insulating and heat-resistant properties. Plate member 400 has a bottom portion 400A and side portions 400B formed to rise from bottom portion 400A in the Z-axis direction. Plate member 400 includes a wall portion 410, openings 420 and 430, and protrusions 440 and 450.

[0035] The wall portion 410 is formed so as to rise in the Z-axis direction from the bottom portion 400A of the plate member 400. The wall portion 410 includes a first wall portion 411 formed on the center side in the X-axis direction and a second wall portion 412 provided on the outer side in the X-axis direction and parallel to the first wall portion 411. The first wall portion 411 and the second wall portion 412 are each formed so as to extend intermittently in the Y-axis direction.

[0036] The first wall 411 and the second wall 412 may function as protective walls that secure a path for gas exhausted from the frame 120 of the battery cell 100 to be exhausted from the battery pack and prevent sparks generated in the plate member 400 from being directly exposed to the outside.

[0037] The opening 420 is located above a position between the electrode terminal 110 and the gas discharge valve 130 in the battery cell 100 located at the end in the Y-axis direction among the stacked battery cells 100. The opening 430 is located above the electrode terminal 110 of each of the battery cells 100.

[0038] The protrusion 440 penetrates the flexible printed circuit board 500 . This helps position the flexible printed circuit board 500 . The protrusion 440 includes a first protrusion 441 and a second protrusion 442 . The first protrusion 441 is used to position the thermistor element, which will be described later. The second protrusion 442 is used to position the connector 600 .

[0039] A plurality of protrusions 450 are formed so as to be aligned in the Y-axis direction. The plurality of protrusions 450 penetrates the flexible printed circuit board 500. The number of protrusions 450 can be changed arbitrarily.

[0040] The flexible printed circuit board 500 is a substrate with a circuit formed on a base material composed of an insulating base film and a conductive metal foil. The base film is made of, for example, polyimide. The conductive metal foil is made of, for example, copper foil. The flexible printed circuit board 500 is flexible and maintains its electrical properties even when deformed.

[0041] The flexible printed circuit board 500 is provided with a bus bar joint 530 electrically connected to the electrode terminal 110. The bus bar joint 530 is joined to the bus bar 100A that connects the electrode terminals 110 of the plurality of battery cells 100. This electrically connects the circuit provided on the flexible printed circuit board 500 to the battery pack 1.

[0042] The connector 600 is fixed to the flexible printed circuit board 500. The circuit in the flexible printed circuit board 500 can be electrically connected to an external electrical device via the connector 600.

[0043] The flexible printed circuit board 500 includes a main body 510 and a displacement absorbing portion 520. The displacement absorbing portion 520 forms a portion of the flexible printed circuit board 500 into a roughly U-shape, making it easily deformable. The displacement absorbing portion 520 is connected to the busbar joint 530. The displacement absorbing portion 520 absorbs displacement of the busbar joint 530 (in the X-axis, Y-axis, and Z-axis directions).

[0044] The flexible printed circuit board 500 has a plurality of elongated holes 540 arranged in the Y-axis direction. The number of elongated holes 540 can be arbitrarily varied. The plurality of protrusions 450 are inserted through each of the elongated holes 540 in a one-to-one correspondence. The length of the elongated holes 540 in the Y-axis direction increases as the distance from the connector 600 increases. This facilitates positioning of the flexible printed circuit board 500 and the connector 600 when placed on the plate member 400.

[0045] A thermistor element 550 is provided on the circuit of the flexible printed circuit board 500. The thermistor element 550 is electrically connected to the circuit of the flexible printed circuit board 500. The thermistor element 550 is disposed on one of the battery cells 100 located at an end in the Y-axis direction among the multiple battery cells 100 in the battery pack 1. The thermistor element 550 contacts the battery cell 100 through the opening 420 and detects the temperature of the battery cell 100. Thus, the thermistor element 550 detects the temperature of the battery cell 100 with the lowest temperature in the battery pack 1. It should be noted that the thermistor element 550 may be used to detect the temperature of the battery cell 100 with the highest temperature in the battery pack 1, or multiple thermistor elements 550 may be used to detect the temperatures of multiple battery cells 100.

[0046] Figure 6 This is a three-dimensional diagram showing the vicinity of the thermistor element. Figure 6 As shown, the opening 420 in the plate member 400 is arranged at a position where the thermistor element 550 and the battery cell 100 are in contact with each other.

[0047] The flexible printed circuit board 500 further includes an extension piece 560, a plate-shaped member 580, and a root portion 590. The extension piece 560 extends from the main body 510 to the opening 420 of the plate member 400. A portion of the circuit 570 of the flexible printed circuit board 500 is provided on the extension piece 560 and is connected to the thermistor element 550.

[0048] Thermistor element 550 is configured on the extension sheet portion 560. In thermistor element 550, two elements are connected in parallel with circuit 570. Thus, thermistor element 550 has the resistance value synthesized by two elements. Therefore, compared with the situation of only utilizing one element to detect temperature, the deviation of detected temperature is reduced. It should be noted that thermistor element 550 is not limited to the structure with two elements connected in parallel, and can also be composed of one element. In addition, among the two elements, it is also possible to make the element (root 590 side) of one side into a capacitor element and the element of the other side into a structure of thermistor element. According to this structure, by removing noise with the capacitor element, it is possible to utilize thermistor element 550 to detect accurate temperature.

[0049] The plate-shaped member 580 is provided on the side of the extension portion 560 opposite the thermistor element 550. The plate-shaped member 580 is provided to improve thermal conductivity between the thermistor element 550 and the battery cell 100 and to facilitate mounting of the thermistor element 550 on the flexible printed circuit board 500. The plate-shaped member 580 is formed of, for example, aluminum.

[0050] The root portion 590 is an end portion of the main body portion 510 and is adjacent to the extending piece portion 560. In the root portion 590, the first protrusion 441 passes through the flexible printed circuit board 500.

[0051] The root portion 590 is wider than the extension piece 560. Specifically, the root portion 590 has a width dimension L1 in the X-axis direction. The extension piece 560 has a width dimension L2 in the X-axis direction. The ratio of the width dimension L1 to the width dimension L2 is, for example, 2 or more and 3 or less. It should be noted that the ratio of the width dimension L1 to the width dimension L2 does not necessarily need to be 2 or more and 3 or less, as long as the extension piece 560 is easily bendable in the Z-axis direction.

[0052] Figure 7 is covered Figure 5 FIG. 7 is a schematic top view of a cover member 700 (bus bar cover) of a wiring module. The cover member 700 is provided on the plate member 400 so as to cover the flexible printed circuit board 500. Figure 7 As shown, the cover member 700 includes a main body 710 , a protrusion 720 , and a projection 730 .

[0053] The protrusion 720 protrudes toward the flexible printed circuit board 500 on the plate member 400. The protrusion 720 has a cylindrical shape.

[0054] The protrusion 730 protrudes toward the plate member 400. The protrusion 730 is provided at a position aligned with the thermistor element 550 in the Z-axis direction.

[0055] The protrusion 730 is bonded to the main body 710. The protrusion 730 is, for example, a resin foam such as sponge. It should be noted that the protrusion 730 can be elastically deformable at least in the Z-axis direction and can be other resin elastic bodies such as rubber or resin springs, or metal elastic bodies.

[0056] Figure 8 This is a cross-sectional view of the thermistor element and its surroundings in the wiring module. Figure 8As shown, the protrusion 730 is located between the cover member 700 and the thermistor element 550 in the Z-axis direction, bending the extension piece 560 and pressing the thermistor element 550 against the battery cell 100. Specifically, the protrusion 730 presses the thermistor element 550, pressing the extension piece 560 and the plate-shaped member 580 together with the thermistor element 550 against the battery cell 100. As a result, the plate-shaped member 580 is in close contact with the battery cell 100.

[0057] Figure 9 This is a cross-sectional view showing the base of the wiring module with the cover component installed. Figure 9 As shown, the protrusion 720 of the cover member 700 contacts the flexible printed circuit board 500. Specifically, the contact surface 720A of the protrusion 720 contacts the flexible printed circuit board 500. Thus, the base portion 590 is fixed to the plate member 400 in the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0058] When the protrusion 720 contacts the flexible printed circuit board 500, the first protrusion 441 is accommodated inside the protrusion 720. Since the circuit 570 of the flexible printed circuit board 500 is located on the outer periphery of the contact surface 720A of the protrusion 720, the circuit 570 and the protrusion 720 do not interfere with each other.

[0059] In the storage battery module of this embodiment, the thermistor element 550 is arranged on the extension piece 560 extending from the wide root portion 590 to the opening portion 420. With the root portion 590 fixed to the plate member 400, the extension piece 560 is bent to press the thermistor element 550 against the battery cell 100. This allows the bending starting point and bending direction of the extension piece 560 to be maintained constant, thereby improving the positioning accuracy of the thermistor element 550 relative to the battery cell 100.

[0060] In the storage battery module of this embodiment, the base portion 590 is secured by the abutment of the protrusion 720, thereby easily improving the positioning accuracy of the thermistor element 550 relative to the battery cell 100. It should be noted that as a structure for securing the base portion 590 to a degree that does not reduce the detection accuracy of the thermistor element 550, a small gap (within 1 mm) may be provided between the abutment surface 720A of the protrusion 720 and the flexible printed circuit board 500. This structure also suppresses positional deviation of the base portion 590 in the X-axis, Y-axis, and Z-axis directions, thereby improving the positioning accuracy of the thermistor element 550 relative to the battery cell 100.

[0061] Hereinafter, a first modified example of the embodiment of the present technology will be described. Figure 10 : is a cross-sectional view near the root of the first variant. Figure 10As shown, the plate member 400 includes a first protrusion 441 that passes through the flexible printed substrate 500 .

[0062] A caulking portion 441A is formed at the tip of the first protrusion 441. The caulking portion 441A is formed, for example, by heat caulking. By caulking the first protrusion 441, the base 590 is fixed to the plate member 400. In this modification, the protrusion 720 of the cover member 700 is not necessarily required.

[0063] In the electricity storage module according to the first modified example of the present embodiment, the positioning accuracy of the thermistor element 550 relative to the battery cell 100 can be easily improved by fixing the base portion 590 by caulking the first protrusion 441 .

[0064] Hereinafter, a second modified example of the embodiment of the present technology will be described. Figure 11 : is a cross-sectional view near the root of the second variant. Figure 11 As shown, the plate member 400 includes a first protrusion 441 that passes through the flexible printed substrate 500 .

[0065] An annular fixing member 441B is fitted onto the outer periphery of the first protrusion 441. The fixing member 441B secures the root portion 590 to the plate member 400. Specifically, the fixing member 441B has an inner diameter smaller than the outer diameter of the first protrusion 441. By pressing the fixing member 441B into the first protrusion 441, the root portion 590 is secured to the plate member 400. In this modified example, the protrusion 720 of the cover member 700 is not necessarily required.

[0066] In the power storage module according to the second modified example of the present embodiment, the positioning accuracy of the thermistor element 550 relative to the battery cell 100 can be easily improved by fixing the base portion 590 by fitting the first protrusion 441 with the fixing member 441B.

[0067] While the embodiments of the present invention have been described, the embodiments disclosed herein are to be construed in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, and is intended to encompass all modifications within the meaning and scope of the claims and equivalents thereof.

Claims

1. A power storage module, wherein: The power storage module comprises: a stacked body in which a plurality of power storage cells are stacked; a resin plate placed on the laminate; a flexible printed circuit board mounted on the resin plate and having a circuit electrically connected to the plurality of power storage cells; a thermistor element provided on the circuit and in contact with one of the plurality of storage cells to detect a temperature of the storage cell; as well as a cover member provided on the resin plate and covering the flexible printed circuit board, The resin plate has an opening at a position where the thermistor element and the power storage unit are in contact with each other. The flexible printed circuit board comprises: a main body; an extension piece extending to the opening of the resin plate; and a root located at an end of the main body, adjacent to the extension piece and wider than the extension piece. The extension piece is located on the side opposite to the main body relative to the root. The thermistor element is arranged on the extension piece, The cover member has a protrusion that protrudes toward the resin plate and bends the extension piece to press the thermistor element against the power storage unit. The root is fixed to the resin plate, The resin plate includes a protrusion that passes through the flexible printed circuit board, and the protrusion is used to position the thermistor element. The cover member has a protrusion protruding toward the flexible printed circuit board on the resin plate, and the protrusion abuts against the flexible printed circuit board, thereby fixing the base portion to the resin plate. When the protrusion contacts the flexible printed circuit board, the protrusion portion is accommodated inside the protrusion, and the circuit of the flexible printed circuit board is provided on the outer peripheral side of the contact surface of the protrusion.

2. The power storage module according to claim 1, wherein The protrusion is caulked to fix the root portion to the resin plate.

3. The power storage module according to claim 1, wherein The electricity storage module further includes a fixing member provided on an outer periphery of the protrusion and fixing the base portion to the resin plate.

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