Energy storage device

Abstract

To provide an energy storage device that makes it easy to maintain the connection between the energy storage cell and the conductive member. [Solution] The energy storage device comprises a first energy storage cell (energy storage cell C1), a second energy storage cell (energy storage cell C2), a first conductor member (conductor member 51), and a second conductor member (conductor member 52). The first energy storage cell and the second energy storage cell are electrically connected to each other via the first conductor member and the second conductor member. The energy storage device further comprises one or more resin members (protrusions 62 of a resin sheet 60) that join the first conductor member and the second conductor member.

Description

Technical Field

[0001] This disclosure relates to a power storage device.

Background Art

[0002] Chinese Patent Application Publication No. 116686151 (Patent Document 1) discloses a power storage device including a plurality of power storage cells fixed within a case (accommodation cavity). The electrode terminals of each power storage cell are provided facing the bottom wall of the case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power storage device described in the above Patent Document 1, it is not always easy to maintain the connection between the power storage cell and the conductor member (for example, a bus bar). For example, when the conductor member vibrates, connection failure (for example, loosening of fastening) is likely to occur at the connection portion between the power storage cell and the conductor member.

[0005] This disclosure has been made to solve the above problems, and its object is to make it easier to maintain the connection between the power storage cell and the conductor member.

Means for Solving the Problems

[0006] According to one aspect of this disclosure, a power storage device is provided. The power storage device includes a first power storage cell, a second power storage cell, a first conductor member, and a second conductor member. The first power storage cell and the second power storage cell are electrically connected to each other via the first conductor member and the second conductor member. And the power storage device further includes one or more resin members that join the first conductor member and the second conductor member. [Effects of the Invention]

[0007] According to this disclosure, it becomes possible to make it easier to maintain the connection between the energy storage cell and the conductive member. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram illustrating the outline of an energy storage device according to an embodiment of the present disclosure. [Figure 2] This figure shows the inside of the energy storage device according to an embodiment of the present disclosure. [Figure 3] Figure 2 is an end view of the energy storage device along line III-III. [Figure 4] Figure 2 is a diagram illustrating the structure of the conductive member shown. [Figure 5] This is a diagram illustrating a conductor member relating to the first modified example. [Figure 6] This is a diagram illustrating a conductor member relating to a second modified example. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated. In the drawings used below, the X-axis, Y-axis, and Z-axis refer to three mutually orthogonal axes. Hereafter, the direction indicated by the arrows on the X-axis, Y-axis, and Z-axis will be indicated by a "+" sign, and the opposite direction will be indicated by a "-" sign.

[0010] Figure 1 is a diagram illustrating the outline of the energy storage device according to this embodiment.

[0011] Referring to Figure 1, the energy storage device B according to this embodiment includes a lower case 100 (first housing member), an upper cover 110 (second housing member), and a shear panel 120 (third housing member), which function as the housing of the energy storage device B. The lower case 100 opens upward (towards the +Z side) and houses a plurality of energy storage cells and various components related to these energy storage cells. As will be described in detail later, the lower case 100 houses the energy storage cells, a cooler, and a junction box (hereinafter referred to as "J / B") (see Figure 2). The upper cover 110 and the shear panel 120 are fixed to the lower case 100. The upper cover 110 is positioned above the lower case 100 and functions as a lid for the lower case 100. The shear panel 120 is positioned below the lower case 100 (towards the -Z side) and suppresses impacts to the lower case 100 due to road surface interference. Furthermore, an exhaust passage is formed between the lower case 100 and the share panel 120.

[0012] When the energy storage device B is mounted on the vehicle, for example, the -Z side is downward (downward in the vertical direction), the +Z side is upward (upward in the vertical direction), the -X side is the front of the vehicle, and the +X side is the rear of the vehicle. The energy storage device B may function as a drive energy storage device, commonly referred to as a "battery pack". The vehicle may be an electric vehicle (BEV) or another electric vehicle (xEV).

[0013] The lower part of Figure 1 shows a view of the lower case 100 in an empty state (nothing contained inside) as seen from above (+Z side). The lower case 100 has a bottom wall 101 (bottom) and a peripheral wall 102 (periphery). The bottom wall 101 includes regions R1 to R5. The peripheral wall 102 includes side walls W1 to W4. Side walls W1, W2, W3, and W4 correspond to the -X side, +X side, -Y side, and +Y side ends of the lower case 100, respectively. Side wall W2 includes side walls W21 to W23. Side walls W21 to W23 are located on the +X side of side walls W3 and W4 which extend in the X direction. Brackets 121 and 122 are provided on side walls W21 and W23, respectively. Discharge valves 151 and 152 are provided on side wall W22. Side wall W22 is connected to side walls W3 and W4 via side walls W21 and W23, respectively. The opposite ends (-X side) of side walls W3 and W4 are connected to each other via side wall W1, which extends in the Y direction. Brackets 131 and 132 are provided on side walls W3 and W4, respectively. Brackets 111 and 112 are provided on side wall W1. Each of side walls W1 to W4 rises from the periphery of the bottom wall 101 towards the +Z side. The internal space of the lower case 100 is enclosed by side walls W1 to W4. The energy storage device B may be connected to the vehicle body (e.g., floor panel) by fastening each bracket to a floor member of the vehicle.

[0014] The bottom wall 101 is provided with partition walls 103 and 104 extending in the Y direction. Each of the partition walls 103 and 104 may be fastened to the bottom wall 101. Partition wall 104 is located on the +X side of partition wall 103. Each of the partition walls 103 and 104 stands upright on the +Z side from the bottom wall 101. Region R5 is a rectangular area located in the center of the lower case 100 and is partitioned by partition walls 103 and 104. Region R5 is the area where the wiring board 200 and energy storage stacks S1 to S6 (see Figure 2), which will be described later, are arranged.

[0015] In region R5, an opening h1 is formed at the position where each energy storage cell is placed. Each of the multiple openings h1 is positioned in the Z direction to face the valve 13 of the energy storage cell 10 (see Figure 3), which will be described later. Multiple openings h1 are arranged in the X direction to form a row of openings h1. A number of rows (rows of openings h1) corresponding to the number of energy storage stacks are formed in the bottom wall 101. An opening h1 is a hole that penetrates the bottom wall 101. The openings h1 are formed, for example, by punching.

[0016] In this embodiment, cover members 141 to 146 are provided in the region R5 of the bottom wall 101. As a result, all openings h1 formed in the bottom wall 101 are covered by the cover members 141 to 146. Each of the cover members 141 to 146 comprises a base material 105 that is elongated in the X direction and N lid portions 105a arranged in the X direction. In this embodiment, the number of energy storage cells included in one energy storage stack is also N. N is, for example, 20 or more and 50 or less. However, it is not limited to this, and N may be 2 or more and less than 20, or it may be more than 50.

[0017] The base material 105 may have an adhesive on one side (the adhesive surface). The base material 105 may be an adhesive tape such as a PP (polypropylene) tape. The N lid portions 105a are formed on the base material 105. In this embodiment, the lid portion 105a contains mica. The N lid portions 105a in the cover members 141, 142, 143, 144, 145, 146 are each formed so as to close an opening h1 located below the power storage stacks S1, S2, S3, S4, S5, S6 (see FIG. 2) described later. The size of the lid portion 105a is the same as or larger than the opening h1. For example, N mica foils may be attached to the adhesive surface of the base material 105 to form N lid portions 105a on the base material 105. Alternatively, N through-holes may be formed in the base material 105, and mica foils may be provided in each of these through-holes to form N lid portions 105a on the base material 105. The cover members 141 to ¹46 are attached to the upper surface (+Z side surface) of the bottom wall 101 via the adhesive surface of the base material 105, for example. As described above, the portion of the lower case 100 facing the valve 13 (FIG. 3) of the power storage cell 10 contains mica. Mica is excellent in heat resistance and electrical insulation.

[0018] Regions R3 and R4 are provided on the -Y side and +Y side of region R5, respectively. Region R1 is provided outside (-X side) of the partition wall 103. Region R2 is provided outside (+X side) of the partition wall 104. Region R2 is a region where a battery circuit unit 30 (FIG. 2) described later is arranged. Region R2 is partitioned by the partition wall 104 and the side wall W2. In this embodiment, each of the bottom wall 101, the peripheral wall 102, and the partition walls 103 and 104 is formed of metal. However, these materials can be changed as appropriate.

[0019] Figure 2 is a top view of the inside of the lower case 100 (the inside of the energy storage device B) with the upper cover 110 removed. Referring to Figure 2, the energy storage stacks S1 to S6, the cooling device 20, the battery circuit unit 30, and the wiring board 200 are housed between the lower case 100 and the upper cover 110. Each of the energy storage stacks S1 to S6 contains N energy storage cells 10 arranged in the X direction. Details of the configuration of each energy storage cell will be described later. The wiring board 200 has wiring patterns for the energy storage stacks S1 to S6. The battery circuit unit 30 includes circuits that are electrically connected to the energy storage stacks S1 to S6. The battery circuit unit 30 may be a single unit or may include multiple units.

[0020] The cooling device 20 comprises ports 20A and 20B, pipes 21A and 21B extending in the Y direction, pipes 22A and 22B extending in the X direction, a plurality of coolers 22C extending in the Y direction, and a cooling pipe 23. These are connected in the order of port 20A, pipe 21A, pipe 22A, cooling pipe 23, pipe 22B, pipe 21B, and port 20B from the upstream side. Pipes 22A and 22B are connected via a plurality of coolers 22C (cooling plates) arranged in the X direction. In each energy storage stack, coolers 22C are placed between adjacent energy storage cells in the X direction. These adjacent energy storage cells are cooled by a refrigerant flowing through a channel formed inside the cooler 22C. The cooler 22C has a channel that communicates with each of the pipes 22A and 22B. The cooling pipe 23 is configured to cool the battery circuit unit 30.

[0021] Referring to FIGS. 1 and 2, ports 20A and 20B are provided on side wall W1. Port 20B is located on the +Y side of port 20A. Pipes 21A and 21B are arranged in region R1. Pipes 22A and 22B are arranged in region R3 and region R4 respectively. Cooling pipe 23 is arranged in region R2. A plurality of coolers 22C are arranged in region R5. The refrigerant supplied from port 20A to pipe 21A flows in pipe 21A toward the -Y side. The refrigerant flowing from pipe 21A into pipe 22A flows in pipe 22A toward the +X side toward cooling pipe 23 while also flowing into the flow paths of each of the plurality of coolers 22C. The refrigerant flowing from pipe 22A into cooler 22C flows toward pipe 22B on the +Y side while sequentially cooling power storage stacks S1 to S6. Also, the refrigerant flowing from pipe 22A into cooling pipe 23 flows toward pipe 22B on the +Y side while cooling battery circuit unit 30. The refrigerant flowing into pipe 22B from cooler 22C or cooling pipe 23 flows in pipe 22B toward pipe 21B on the -X side. Thereafter, the refrigerant flows in pipe 21B toward the -Y side and flows out from port 20B. The refrigerant may be a liquid (such as water, oil, antifreeze, etc.) or a gas.

[0022] In this embodiment, wiring board 200 is arranged on the +Z side of bottom wall 101, and power storage stacks S1 to S6 are further arranged on the +Z side of wiring board 200.

[0023] FIG. 3 is an end view of power storage device B taken along line III-III in FIG. 2. Also, on the left side of FIG. 3, a perspective view of power storage cell 10 is shown.

[0024] As shown in the perspective view on the left side of Figure 3, the energy storage cell 10 comprises a case 10a and an electrode body 10b housed in the case 10a. The case 10a is a rectangular case in the shape of a rectangular parallelepiped. The electrode body 10b may include one or more windings (for example, two windings). The windings have a structure in which, for example, a positive electrode sheet and a negative electrode sheet are wound with a separator in between. Each of the positive electrode sheet and the negative electrode sheet includes an electrode foil and an active material layer. The energy storage cell 10 is a secondary battery such as a lithium-ion battery, a nickel-metal hydride battery, or a sodium-ion battery. In this embodiment, a liquid-type lithium-ion battery is used as the energy storage cell 10. The case 10a houses the electrolyte together with the electrode body 10b. The type of secondary battery is arbitrary, and for example, it may be an all-solid-state secondary battery. A laminate (for example, a laminate in which a positive electrode sheet and a negative electrode sheet are laminated with a separator in between) may be used instead of windings.

[0025] The energy storage cell 10 has electrode terminals 11 and 12 and a valve 13 on the same plane. Specifically, the electrode terminals 11 and 12 and the valve 13 are provided on a surface F10 of the case 10a. Surface F10 corresponds to one end face of the energy storage cell 10 in the height direction (Z direction). The valve 13 functions as an exhaust valve. The case 10a is basically maintained in a sealed state. However, if the pressure inside the case 10a exceeds a first reference value, the valve 13 opens to reduce the pressure inside the case 10a. Also, the electrode terminals 11 and 12 are electrically connected to the positive electrode sheet and negative electrode sheet of the electrode body 10b, respectively, and function as positive electrode terminals and negative electrode terminals. The parts of the case 10a surrounding the electrode terminals 11 and 12 may be formed of an insulating material, and the other parts may be formed of metal. However, the material of the case 10a is arbitrary and not limited to this.

[0026] In this embodiment, each energy cell included in the energy storage stacks S1 to S6 has the same configuration (the configuration shown in Figure 3). By forming the energy storage stacks S1 to S6 using a common energy storage cell 10, the manufacturing of the energy storage device B becomes easier and manufacturing costs can be reduced. However, this is not limited to this, and each energy storage stack may include multiple types of energy storage cells. Also, the number of energy storage stacks can be changed as appropriate. The number of energy storage stacks may be one or more.

[0027] Each energy cell in the energy storage stack S1 to S6 is electrically connected by the wiring pattern on the wiring board 200. The wiring board 200 is, for example, a panel on which a wiring pattern is formed. An example of the wiring pattern on the wiring board 200 is shown at the bottom of Figure 2.

[0028] Specifically, the wiring board 200 comprises a rectangular substrate 201, a plurality of conductor members 211, a plurality of conductor members 212, a plurality of conductor members 213, a plurality of conductor members 214, a plurality of conductor members 215, a plurality of conductor members 216, conductor members 221 to 223, and conductor members 231 to 236. The substrate 201 is an insulating substrate having insulating properties. The substrate 201 may contain a resin (for example, a thermosetting resin).

[0029] Each of the multiple conductor members 211 electrically connects the energy cells included in the energy storage stack S1. Each of the multiple conductor members 212 electrically connects the energy cells included in the energy storage stack S2. Each of the multiple conductor members 213 electrically connects the energy cells included in the energy storage stack S3. Each of the multiple conductor members 214 electrically connects the energy cells included in the energy storage stack S4. Each of the multiple conductor members 215 electrically connects the energy cells included in the energy storage stack S5. Each of the multiple conductor members 216 electrically connects the energy cells included in the energy storage stack S6.

[0030] Conductor member 221 electrically connects energy storage stacks S1 and S2. Conductor member 222 electrically connects energy storage stacks S3 and S4. Conductor member 223 electrically connects energy storage stacks S5 and S6. Conductor members 231, 232, 233, 234, 235, and 236 electrically connect energy storage stacks S1, S2, S3, S4, S5, and S6 to the battery circuit unit 30, respectively.

[0031] In this embodiment, the wiring pattern of the wiring board 200 is formed by the above-described conductor members. Each of the conductor members 211-216, 221-223, and 231-236 is, for example, a metal plate-shaped member. Each of the conductor members 221-223 may be a U-shaped plate-shaped member. Each conductor member may also be a busbar. In this embodiment, each conductor member is fixed in a recess formed in the surface (+Z side) of the substrate 201. The lower part of each conductor member is embedded in the substrate 201. However, it is not essential that recesses (steps) for each conductor member be formed on the surface of the substrate 201. Each conductor member may be bonded to a flat surface of the substrate 201. Furthermore, the material and shape of each conductor member are arbitrary.

[0032] The wiring board 200 is electrically connected to the battery circuit unit 30. As shown in Figure 2, the battery circuit unit 30 includes a total positive terminal 31, a total negative terminal 32, a J / B 33, a fuse 34, and wires L1 to L4. The total positive terminal 31 is located at the positive terminal end of the entire energy storage stack S1 to S6 (all energy storage cells). The total negative terminal 32 is located at the negative terminal end of the entire energy storage stack S1 to S6 (all energy storage cells). Wire L1 electrically connects conductor member 232 and conductor member 233. Wire L2 electrically connects conductor member 234 and conductor member 235. A fuse 34 is provided on wire L2. Conductor member 236 is connected to the total positive terminal 31. Wire L3 electrically connects the total positive terminal 31 and the J / B 33. Conductor member 231 is connected to the total negative terminal 32. The wire L4 electrically connects the total negative terminal 32 to J / B33. J / B33 houses various electrical devices. J / B33 may include at least one of a relay, fuse, resistor, current sensor, and connector (e.g., a connector to an onboard charger). The battery circuit unit 30 may further include at least one of a BMS (Battery Management System) and an ECU (Electronic Control Unit).

[0033] An opening may be formed in the partition wall 104 for passing the conductor members 231 to 236 through. Alternatively, a wire (e.g., a cable) connected to the wiring board 200 may be connected to the battery circuit unit 30 by passing over the partition wall 104. Note that partition walls 103 and 104 are not essential components. At least one of partition walls 103 and 104 may be omitted.

[0034] Each energy storage stack S1 to S6 contains the same number of energy storage cells, and the cells are arranged so that their positions are aligned. As a result, six energy storage cells 10 aligned in the Y direction form a row (a row in the Y direction). These rows are then aligned in the X direction. 6 × N energy storage cells 10 are arranged in a matrix with 6 rows in the Y direction and N rows in the X direction. In the wiring pattern shown in Figure 2, multiple parallel connections are connected in series. In each energy storage stack, N energy storage cells 10 are arranged so that the positional relationship between the electrode terminals 11 (positive terminal) and electrode terminals 12 (negative terminal) is reversed every two cells. Each of the conductor members 211 to 216 connects two energy storage cells in parallel in the corresponding energy storage stack, and the resulting parallel connections (multiple energy storage cells connected in parallel) are connected in series. The connection configuration of the multiple energy storage cells can be changed as appropriate. For example, the number of energy storage cells connected in parallel may be three or more, not just two. Alternatively, all energy storage cells may be connected in series without forming parallel connections.

[0035] In the substrate 201 of the wiring board 200, openings h2, as shown in Figure 3, are formed at the same positions as openings h1 (Figure 1) in the XY plane. Each of the same number of openings h2 (6 × N) as openings h1 faces the valve 13 of the energy storage cell 10 in the Z direction. Openings h2 are holes that penetrate the substrate 201. Openings h2 have larger dimensions than openings h1 (Figure 1) in the XY plane. In the XY plane, openings h1 are located inside openings h2. As shown in Figure 3, each opening h2 is connected to opening h1 via a cover portion 105a. Openings h2 are formed, for example, by punching.

[0036] In the manufacturing of the energy storage device B, for example, after installing the wiring board 200 inside the lower case 100, the energy storage stacks S1 to S6 are mounted on the wiring board 200 with the surface F10 of each energy storage cell facing downwards in the vertical direction. The electrode terminals of the energy storage cells 10 and the conductor members of the wiring board 200 may be joined by crimping, heat pressing, welding (e.g., laser welding), or conductive adhesive. Then, the battery circuit unit 30 is connected to the wiring board 200, and the cooling device 20 is installed inside the lower case 100. As a result, the inside of the lower case 100 is in the state shown in Figure 2. Of the cooling device 20, the cooler 22C may be installed inside the lower case 100 together with the energy storage stacks S1 to S6. After that, the remaining part of the cooling device 20 may be placed inside the lower case 100, and the pipes 22A and 22B may be connected to the cooler 22C. The wiring board 200 and the battery circuit unit 30 may each be fixed to the lower case 100 with adhesive.

[0037] As shown in Figure 3, the upper cover 110 is joined to the upper surface (+Z side) of each of the side walls W1 to W4 (only side wall W3 is shown in Figure 3) via, for example, adhesive 110b, and further fastened with bolts 110a. In addition, the shear panel 120 is joined to the lower surface (-Z side) of each of the side walls W1 to W4 via, for example, adhesive 120b. Although not shown in Figure 3, the piping 22A shown in Figure 2 is located in the space V3 between the energy storage cell 10 located at the -Y end of the lower case 100 and the side wall W3.

[0038] An exhaust passage P1 is formed between the bottom wall 101 of the lower case 100 and the shear panel 120. Each of the side walls W1 to W4 is formed in a hollow shape. As shown in Figure 3, an exhaust passage P3 is formed inside side wall W3. Although not shown, exhaust passages are also formed inside side walls W2 and W4 in a manner similar to the exhaust passage P3 of side wall W3. These exhaust passages are in communication with each other. In addition, exhaust holes connected to discharge valves 151 and 152 (Figure 2) are formed in side wall W2. These exhaust holes are in communication with the exhaust passages.

[0039] When the internal pressure of the energy storage cell 10 exceeds a first reference value, valve 13 opens as shown in Figure 3. Then, the pressure and heat of the gas discharged from inside the energy storage cell 10 through valve 13 create a hole in the cover portion 105a facing valve 13. The gas discharged from the energy storage cell 10 flows into the exhaust passage P1 through this hole. Each of the discharge valves 151 and 152 shown in Figure 2 opens when the pressure in the exhaust passage exceeds a second reference value. The second reference value may be a pressure value lower than the first reference value. For example, check valves are used for each of the discharge valves 151 and 152. When at least one of the discharge valves 151 and 152 opens, the gas in each exhaust passage flows toward the opened discharge valve and is discharged to the outside of the energy storage device B through that valve. The thickness of the lid portion 105a provided on the lower case 100 (Figure 1) is set to a thickness such that a hole is created when the opposing valve 13 opens (for example, when the valve opens in a manner that causes ignition).

[0040] A mica layer 120a (for example, mica foil) is provided on the inner (+Z side) surface of the shear panel 120. The mica layer 120a may be provided so as to overlap all of the cover portions 105a in the XY plane. The mica layer 120a protects the shear panel 120 from substances (gas, electrolyte, debris, etc.) released from the energy storage cell 10 through the cover portions 105a.

[0041] In this embodiment, each of the conductor members 211 to 216 included in the wiring board 200 has a two-layer structure consisting of two conductor members joined by a resin member. Specifically, each of the conductor members 211 to 216 is a conductor member 50 having the structure shown in Figure 4. That is, the wiring board 200 has a wiring pattern (Figure 2) formed by a plurality of conductor members 50. Figure 4 is a diagram illustrating the structure of each of the conductor members 211 to 216 in the wiring board 200. The upper left of Figure 4 shows a plan view of the conductor member 50. The lower left of Figure 4 shows an end view of the conductor member 50 in the IV-IV line in the plan view. The right side of Figure 4 shows the method of joining the two conductor members that constitute the conductor member 50.

[0042] As shown in Figure 4, the conductor member 50 has a two-layer structure consisting of a conductor member 51 (first conductor member) and a conductor member 52 (second conductor member) arranged in the Z direction. Each of the conductor members 51 and 52 is made of metal (for example, copper). Each of the conductor members 51 and 52 constituting the conductor member 50 has a rectangular planar shape in the XY plane. Each of the conductor members 51 and 52 is formed to be elongated in the X direction. The conductor members 51 and 52 have the same dimensions in the X, Y, and Z directions, and are arranged so that their entire areas overlap in the Z direction. However, this is not limited to the conductor member 51 and the conductor member 52, and they may have different thicknesses (dimensions in the Z direction). The conductor member 50 is connected to four energy storage cells 10 shown by dashed lines in the plan view in Figure 4. Hereinafter, these four energy storage cells 10 will be distinguished and referred to as "energy storage cell C1", "energy storage cell C2", "energy storage cell C3", and "energy storage cell C4" from the -X side.

[0043] The conductor member 50 has a first mounting portion (first part) connected to the electrode terminal 12 of the energy storage cell C1 (first energy storage cell), a second mounting portion (second part) connected to the electrode terminal 12 of the energy storage cell C2 (second energy storage cell), a third mounting portion (third part) connected to the electrode terminal 11 of the energy storage cell C3 (third energy storage cell), and a fourth mounting portion (fourth part) connected to the electrode terminal 11 of the energy storage cell C4 (fourth energy storage cell). The energy storage cells C1 to C4 are electrically connected to each other via the conductor member 50 (joined conductor members 51 and 52). Each of the energy storage cells C1 to C4 has electrode terminals 11, 12 and a valve 13 (exhaust valve) on a vertically downward-facing surface F10 (see Figure 3). Although not shown in Figure 4, the coolers 22C shown in Figure 2 are positioned between two adjacent energy storage cells in the X direction (between energy storage cells C1 and C2, between energy storage cells C2 and C3, and between energy storage cells C3 and C4).

[0044] In the conductor member 50, conductor members 51 and 52 are joined by a resin sheet 60. The conductor member 50 and the resin sheet 60 are positioned within a recess R10 formed on the +Z side of the substrate 201. However, the surface F21 (+Z side) of the conductor member 50 is located on the +Z side of the substrate 201 than the surface F22 (+Z side). In other words, the conductor member 50 protrudes from the substrate 201 on the +Z side. This makes it easier to mount the electrode terminals of the energy storage cell 10 onto the conductor member 50.

[0045] The resin sheet 60 has a plate-shaped main body 61 and a plurality of protrusions 62. Each protrusion 62 projects from the main body 61 toward the +Z direction. The main body 61 is formed in the shape of a plate in the XY plane, and each of the plurality of protrusions 62 extends in the Z direction. The main body 61 and the plurality of protrusions 62 may be formed separately and joined together, or they may be formed seamlessly and integrally.

[0046] In this embodiment, the resin sheet 60 has three protrusions 62 (first to third protrusions). The first protrusion is a protrusion 62 located between the first and second mounting portions of the conductor member 50. The second protrusion is a protrusion 62 located between the second and third mounting portions of the conductor member 50. The third protrusion is a protrusion 62 located between the third and fourth mounting portions of the conductor member 50. The conductor member 50 has three through holes 50a formed at positions corresponding to the first to third protrusions. Each through hole 50a penetrates the conductor member 50 in the Z direction. Each of the first to third protrusions is inserted into the corresponding through hole 50a and fastens the conductor member 51 and the conductor member 52. Each of the first to third protrusions functions as a solid resin rivet. Each of the first to third protrusions fastens the overlapping portion of the conductor member 51 and the conductor member 52. In this embodiment, each protrusion 62 of the resin sheet 60 penetrates the conductor members 51 and 52, and joins the conductor members 51 and 52 together. The main body 61 of the resin sheet 60 is in contact with the -Z side surface of the conductor member 50 and supports the conductor member 50. With this resin sheet 60, it becomes easier to maintain the connection between the conductor member 51 and the conductor member 52.

[0047] When the energy storage device B (see Figures 1 and 2) is mounted on a vehicle, vibrations may be applied to the conductor members 211 to 216 due to road surface interference or other factors. Therefore, in this embodiment, each of the conductor members 211 to 216 shown in Figure 2 is replaced with a conductor member 50 having the structure shown in Figure 4, thereby suppressing connection failures caused by such vibrations. Specifically, in the conductor member 50, conductor members 51 and 52 are joined by a resin member (resin sheet 60). Resin members are more elastically deformable than metals, and therefore absorb vibrations more easily. Furthermore, the two-layer structure of the conductor member 50 also facilitates vibration absorption. As a result of the conductor member 50 and the resin sheet 60 absorbing vibrations, vibrations are less likely to be transmitted to the connection between the energy storage cell 10 and the conductor member 50 (specifically, the connection between the electrode terminal 11 or 12 and the conductor member 50). This vibration damping and isolation effect makes it easier to maintain the connection between the energy storage cell 10 and the conductor member 50. Furthermore, maintaining the connection between the energy storage cell 10 and the wiring board 200 reduces the likelihood of misalignment between the valve 13 and the opening h1 or h2 (see Figure 3).

[0048] In this embodiment, the entire resin sheet 60 is formed of a thermoplastic resin in which multiple metal filler particles are dispersed. The thermoplastic resin may be nylon resin or polyamide resin. Compared to thermosetting resins, thermoplastic resins absorb vibrations more easily and are easier to process. In addition, the electrical conductivity and mechanical strength of the resin sheet 60 are improved by each metal filler particle dispersed in the thermoplastic resin. The multiple metal filler particles may include at least one of gold particles, silver particles, copper particles, and nickel particles. The main body 61 and each protrusion 62 of the resin sheet 60 may be formed of different materials. For example, of the main body 61 and each protrusion 62, only each protrusion 62 may contain multiple metal filler particles. Alternatively, the resin sheet 60 may be formed only of resin without containing metal filler particles.

[0049] The conductor members 51 and 52 are joined, for example, in the manner shown on the right side of Figure 4. Specifically, the resin sheet 60 is placed in the recess R10 of the substrate 201. Then, the conductor members 51 and 52, each having three through holes in corresponding positions, are stacked to form a conductor member 50 having three through holes 50a. Subsequently, the conductor member 50 is also placed in the recess R10 of the substrate 201 so that the three protrusions 62 of the resin sheet 60 are each inserted into the three through holes 50a of the conductor member 50. The substrate 201 and the resin sheet 60 (main body 61) may be joined by any method (for example, welding, brazing, or adhesive). The substrate 201 and the resin sheet 60 may also be integrally molded products.

[0050] Subsequently, the three protrusions 62 are pressed from the +Z side using a heated plate 600 to deform the tip of each of the three protrusions 62. At this time, the tip of each protrusion 62 may be crushed while melting the resin with heat. After that, each processed protrusion 62 is cooled. This forms the head of the resin rivet, and the conductor member 51 and the conductor member 52 are fastened together by the three protrusions 62.

[0051] Not only conductor members 211-216, but also each of conductor members 221-223 and 231-236 may have a two-layer structure similar to conductor member 50 shown in Figure 4. However, the structure of each conductor member included in the wiring board 200 is not limited to the structure shown in Figure 4. For example, each of conductor members 221-223 may have a structure other than that shown in Figure 4, such as the structure shown in Figure 5.

[0052] Figure 5 is a diagram illustrating the conductor member according to the first modified example. In the energy storage device according to the first modified example, a conductor member 70 having the structure shown in Figure 5 is used as each of the conductor members 221 to 223 shown in Figure 2. Figure 5 shows a plan view of the conductor member 70, as well as end views of the conductor member 70 along the AA line and BB line in the plan view.

[0053] As shown in Figure 5, the conductor member 70 has a conductor member 71 (first conductor member), a conductor member 72 (second conductor member), and a conductor member 73 (third conductor member). Each of the conductor members 71 to 73 is made of metal (for example, copper). The conductor member 70 has a U-shaped planar shape in the XY plane. Each of the conductor members 71 to 73 has a rectangular planar shape in the XY plane. The conductor member 71 is formed to be elongated in the Y direction. Each of the conductor members 72 and 73 is formed to be elongated in the X direction. The conductor member 72 is connected to the electrode terminals 11 of each of the two energy storage cells 10 that are aligned in the X direction. The conductor member 73 is connected to the electrode terminals 12 of each of the two energy storage cells 10 that are aligned in the X direction. The conductor member 72 and the conductor member 73 are electrically connected to each other via the conductor member 71.

[0054] Conductor member 71 and conductor member 72 are joined by resin member 81 (first resin member). Specifically, conductor member 71 and conductor member 72 are arranged at right angles so that parts of each overlap. Resin member 81 fastens the overlapping portion of conductor member 71 and conductor member 72. Also, conductor member 71 and conductor member 73 are joined by resin member 82 (second resin member). Conductor member 71 and conductor member 73 are arranged at right angles so that parts of each overlap. Resin member 82 fastens the overlapping portion of conductor member 71 and conductor member 73. Each of resin members 81 and 82 has a head at both ends in the Z direction and functions as a resin rivet. Ring-shaped sealing members 91a and 92a are provided between the +Z side heads of resin members 81 and 82 and conductor members 72 and 73, respectively. Ring-shaped sealing members 91b and 92b are provided between the -Z side heads of resin members 81 and 82 and conductor member 71, respectively. Each sealing member may be an elastic material. Each sealing member may be an O-ring made of heat-resistant rubber. However, it is not limited to these, and each sealing member may be made of a soft metal (for example, aluminum).

[0055] Of the conductor members 70, conductor member 71 is positioned within a recess R21 formed on the +Z side of the substrate 201. The overlapping portions of conductor member 71 and conductor member 72, and the overlapping portions of conductor member 71 and conductor member 73 are also positioned within the recess R21. Recesses R31 and R32 are further formed on the bottom surface of the recess R21, accommodating the -Z side heads of resin members 81 and 82, respectively. Recesses R31 and R32 (counterbores) may be used for positioning.

[0056] The portion of the conductor member 73 that does not overlap with the conductor member 71 is placed in a recess R22 formed on the +Z side of the substrate 201. However, a portion of the conductor member 73 protrudes further towards the +Z side than the surface (+Z side) of the substrate 201. The depth dimension of the recess R22 is smaller than the depth dimension of the recess R21. The recess R22 is formed shallower than the recess R21 by the thickness of the conductor member 71. As a result, the height of the -Z side surface of the conductor member 73 matches the height of the bottom surface of the recess R22. The conductor member 73 is supported by the substrate 201 within the recess R22.

[0057] Although not shown in Figure 5, the substrate 201 has further recesses formed in a manner similar to the recess R22, which accommodate the portion of the conductor member 72 that does not overlap with the conductor member 71. The conductor member 72 is also supported by the substrate 201 within these recesses. In addition, a portion of the conductor member 72 protrudes on the +Z side beyond the surface (+Z side) of the substrate 201.

[0058] Conductor member 71 and each of the conductor members 72 and 73 are joined together, for example, by the method shown on the right side of Figure 5. More specifically, resin members 81 and 82 are formed by injection molding. Although Figure 5 only shows the method for forming resin member 81, resin member 82 is formed by the same method.

[0059] As shown in Figure 5, a through hole h10 is formed at the position corresponding to the resin member 81 in the overlapping portion of the conductor member 71 and the conductor member 72. Then, sealing members 91a and 91b are provided at the +Z and -Z edges of the through hole h10, respectively. Next, the molds are set on the conductor members 71 and 72. Molds 701 and 702 are used as molds. Liquid resin is injected from the injection nozzle 701a provided on mold 701. At this time, the sealing members 91a and 91b each prevent the resin from flowing out of the molds (molds 701 and 702). In this embodiment, a thermoplastic resin containing a large number of metal filler particles is injected into the inside of the mold. However, it is not limited to this, and the liquid resin may be a thermosetting resin (for example, an epoxy resin). Also, instead of each sealing member, resin retaining claws may be provided on the mold.

[0060] Subsequently, the inside of the mold (molds 701, 702) is cooled while maintaining pressure, and the resin is solidified. Once the resin (resin member 81) has solidified, the mold is opened (demolition). This forms the resin member 81. Resin members 81 and 82 may be formed simultaneously. After demolding, the conductive members 71-73 joined by resin members 81 and 82 may be removed and placed in the recess R21 of the substrate 201.

[0061] Figure 6 is a diagram illustrating the conductor member according to the second modified example. The energy storage device according to the second modified example has the same configuration as the energy storage device according to the first modified example shown in Figure 5, except that the sealing members 91a, 91b, 92a, and 92b are omitted, resin members 81A and 82A are used instead of resin members 81 and 82, and recess R21A is used instead of recess R21. Each of the resin members 81A and 82A has a head only at the +Z end of both ends in the Z direction. The bottom surface of recess R21A does not have a recess formed to accommodate the head of a resin rivet.

[0062] As shown on the right side of Figure 6, the conductor members 71 and 72 may be fastened by the resin member 81A by press-fitting the resin member 81A into the through hole h10A of the conductor member 70. The through hole h10A is formed at a position corresponding to the resin member 81A. When press-fitted, the resin member 81A deforms to form the body and head of the resin member 81A (resin rivet). The conductor members 71 and 72 (e.g., busbars) may also be energized, and the resin member 81A may be press-fitted into the heated conductor members 71 and 72. This makes the resin member 81A (e.g., thermoplastic resin) easier to deform. With this method, multiple conductor members can be easily fastened by embedding resin plugs in the through holes of the conductor members. Figure 6 shows only the fastening method using resin member 81A, but the fastening method using resin member 82A is similar.

[0063] The various features of the energy storage device described above (each feature described in the embodiments and modifications) may be applied in any combination. The application of the energy storage device is arbitrary. The energy storage device may be used in vehicles other than automobiles, mobile machinery (agricultural machinery, construction machinery, etc.), unmanned mobile bodies, robots, or buildings.

[0064] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0065] 10 Energy storage cell, 11,12 Electrode terminals, 13 Valve, 50~52,70~73,211~216 Conductor members, 60 Resin sheet, 61 Main body, 62 Protrusion, 81,81A,82,82A Resin members, 200 Wiring board, 201 Circuit board, B Energy storage device.

Claims

1. An energy storage device comprising a first energy storage cell, a second energy storage cell, a first conductor member, and a second conductor member, The first energy storage cell and the second energy storage cell are electrically connected to each other via the first conductor member and the second conductor member. The energy storage device further comprises one or more resin members that join the first conductor member and the second conductor member.

2. Each of the first conductor member and the second conductor member has a rectangular planar shape, The first conductor member and the second conductor member are arranged so that their entire areas overlap. The one or more resin members include a resin member that fastens the overlapping portion of the first conductor member and the second conductor member. The energy storage device according to claim 1, wherein the joined first conductor member and second conductor member have a first portion connected to the electrode terminals of the first energy storage cell and a second portion connected to the electrode terminals of the second energy storage cell.

3. The one or more resin members include a resin sheet having a plurality of protrusions, The energy storage device according to claim 1, wherein each of the plurality of protrusions penetrates the first conductor member and the second conductor member and joins the first conductor member and the second conductor member.

4. The energy storage device according to any one of claims 1 to 3, wherein the one or more resin members are formed of a thermoplastic resin in which a plurality of metal filler particles are dispersed.

5. The aforementioned energy storage device further comprises an upper cover, a lower case, a share panel, a wiring board, and a cooler. The first energy storage cell, the second energy storage cell, and the wiring board are housed between the lower case and the upper cover. The wiring board has a wiring pattern formed by a plurality of conductor members, including the first conductor member and the second conductor member. The cooler is positioned between the first energy storage cell and the second energy storage cell. Each of the first and second energy storage cells has electrode terminals and an exhaust valve on its vertically downward-facing surface. The energy storage device according to any one of claims 1 to 3, wherein an exhaust passage is formed between the lower case and the share panel.

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