Energy storage device

Abstract

This suppresses the decrease in contact between the energy storage element and the heat exchanger when the element deforms. [Solution] The energy storage device comprises a plurality of energy storage cells 29 and a heat exchange plate 32 that is positioned between the plurality of energy storage cells 29, facing the long sides of the plurality of energy storage cells 29, and extending in the longitudinal direction of the long sides. The energy storage cells 29 and the heat exchange plate 32 are bonded together with an adhesive. The energy storage device is configured such that the adhesive strength at the center of the short side of the long side is greater than the adhesive strength at the short end of the long side.

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Conventionally, various technologies related to power storage devices have been proposed. For example, Japanese Unexamined Patent Application Publication No. 2023-123690 (Patent Document 1) discloses a technique in which a heat exchanger is provided between power storage elements constituting a power storage device to absorb expansion and contraction of the power storage elements.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the amount of expansion or contraction in the power storage element increases, if the deformation of the heat exchanger cannot follow, the adhesion between the power storage element and the heat exchanger decreases, and the heat exchange performance including the cooling performance may decrease.

[0005] <好 The present disclosure has been made in view of the above problems, and an object thereof is to provide a power storage device that suppresses a decrease in adhesion to a heat exchanger when a power storage element is deformed.

Means for Solving the Problems

[0006] A power storage device according to an aspect of the present disclosure includes a plurality of power storage elements and a heat exchanger that is disposed between the plurality of power storage elements so as to face a long side surface of the plurality of power storage elements and extends in the longitudinal direction of the long side surface. The power storage element and the heat exchanger are adhered to each other. The adhesion strength at the center in the short side direction of the long side surface is greater than the adhesion strength at the end in the short side direction of the long side surface.

[0007] In this configuration, the adhesive strength at the center of the long side in the short direction is greater than the adhesive strength at the ends in the short direction. Therefore, even if a force acts on the center that would relatively increase the distance between the energy storage element and the heat exchanger during contraction or expansion of the energy storage element, the high-strength adhesive maintains the distance between the energy storage element and the heat exchanger. This suppresses a decrease in the adhesion between the energy storage element and the heat exchanger.

[0008] In one embodiment, the heat exchanger has a surface treatment applied to the center of the shorter side of its long surface.

[0009] This method allows the adhesive strength between the heat exchanger and the energy storage element to be greater in the surface-treated central section than at the edges. As a result, the distance between the heat exchanger and the energy storage element is maintained in the central section even when the energy storage element contracts or expands. This suppresses a decrease in the adhesion between the energy storage element and the heat exchanger.

[0010] Furthermore, in one embodiment, the energy storage element and the heat exchanger are bonded together with an adhesive. The adhesive application area per unit area of ​​the heat exchanger in the central part in the short direction is larger than the adhesive application area per unit area of ​​the heat exchanger at the ends in the short direction.

[0011] This configuration allows for greater adhesion between the heat exchanger and the energy storage element in the central region compared to the edges. As a result, the distance between the heat exchanger and the energy storage element is maintained in the central region even during contraction and expansion of the energy storage element. This suppresses a decrease in adhesion between the energy storage element and the heat exchanger.

[0012] Furthermore, in one embodiment, the adhesive strength of the adhesive placed in the center in the short direction is greater than the adhesive strength of the adhesive placed at the ends in the short direction.

[0013] In this configuration, the adhesive strength between the heat exchanger and the energy storage element in the central part is greater than at the edges, thus maintaining the distance between the heat exchanger and the energy storage element in the central part even when the energy storage element contracts or expands. This suppresses a decrease in the adhesion between the energy storage element and the heat exchanger.

[0014] Furthermore, in one embodiment, the Young's modulus of the central part of the heat exchanger in the short direction is smaller than the Young's modulus of the ends in the short direction.

[0015] In this configuration, the Young's modulus of the central part of the heat exchanger is smaller than that of the ends of the heat exchanger. As a result, deformation of the central part of the heat exchanger in response to the contraction and expansion of the energy storage element is relatively more tolerable than deformation of the ends, thus maintaining a tighter seal. Therefore, a decrease in the seal between the energy storage element and the heat exchanger can be suppressed.

[0016] Furthermore, in one embodiment, the central part of the heat exchanger is positioned to overlap with the central part of the electrode body housed within the energy storage element when viewed from a first direction perpendicular to both the longitudinal and transverse directions.

[0017] In this configuration, the areas of the energy storage element that experience large contractions or expansions overlap with the central part of the heat exchanger where a high-strength adhesive is applied, thus suppressing a decrease in the adhesion between the energy storage element and the heat exchanger. [Effects of the Invention]

[0018] According to this disclosure, it is possible to provide an energy storage device that suppresses the decrease in adhesion between the energy storage element and the heat exchanger when the energy storage element is deformed. [Brief explanation of the drawing]

[0019] [Figure 1] This diagram schematically shows a vehicle 1 equipped with an energy storage device 2. [Figure 2] This is an exploded perspective view showing the energy storage device 2. [Figure 3] This is a perspective view showing the energy storage cell 29. [Figure 4] It is a plan view showing a cooling device 12 etc. [Figure 5] It is a perspective view showing the cooling device 12. [Figure 6] It is a cross-sectional view showing the heat exchange plate 32. [Figure 7] It is a figure showing an example of the configuration of the heat exchange plate 32. [Figure 8] It is a figure showing an example of a cross-section of the heat exchange plate 32, the adhesive, and the power storage cell 29. [Figure 9] It is a figure showing an example of a cross-section of the heat exchange plate 32, the adhesive, and the power storage cell 29 in a modified example. [Figure 10] It is a figure showing another example of a cross-section of the heat exchange plate 32, the adhesive, and the power storage cell 29 in a modified example. [Figure 11] It is a figure showing an example of the Young's modulus at the central part 32c in the elastic region and the Young's modulus of the end parts 32b, 32d. [Figure 12] It is a figure showing an example of a cross-section of the heat exchange plate 32 in a modified example. [Figure 13] It is a figure showing another example of a cross-section of the heat exchange plate 32 in a modified example. [Figure 14] It is a figure showing yet another example of a cross-section of the heat exchange plate 32 in a modified example. [Figure 15] It is a figure showing another example of a cross-section of the heat exchange plate 32 in a modified example. [Figure 16] It is a figure showing an example of a cross-section of the heat exchange plate 32 in another modified example. [Figure 17] It is a figure showing an example of a cross-section of the heat exchange plate 32, the power storage cell 29, and the electrode body 5 in a modified example. [Figure 18] It is a figure showing an example of a cross-section of the heat exchange plate 32 in yet another modified example.

Embodiments for Carrying Out the Invention

[0020] The embodiments of this disclosure will be described in detail below 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.

[0021] Figure 1 is a schematic diagram showing a vehicle 1 equipped with an energy storage device 2. The vehicle 1 includes the vehicle body 3, and the energy storage device 2 is mounted on the bottom of the vehicle body 3.

[0022] Figure 2 is an exploded perspective view showing the energy storage device 2. In Figure 2, the width direction W is the width direction of the energy storage device 2, and is also the vehicle width direction of the vehicle 1. The longitudinal direction L is the longitudinal direction of the energy storage device 2, and is also the longitudinal direction of the vehicle 1. The vertical direction H is the vertical direction in the vertical direction.

[0023] The energy storage device 2 includes a housing case 10, an energy storage module 11, a cooling device 12, and electrical equipment 13. The housing case 10 includes a lower case 15, an upper case 16, an insulating plate 17, and a shear panel 18.

[0024] The lower case 15 is formed to open upward, and the upper case 16 is provided to close the opening of the lower case 15.

[0025] The lower case 15 includes a bottom plate 20, a peripheral wall 21, partition walls 22, 23, and an insulating plate 24.

[0026] The base plate 20 is formed in a plate shape. The peripheral wall 21 is formed along the outer edge of the base plate 20. The peripheral wall 21 includes a side wall 25, a side wall 26, an end plate 27, and an end plate 28.

[0027] The side walls 25 and 26 are arranged in the width direction W, and the side walls 25 and 26 are formed to extend in the front-rear direction L.

[0028] End plates 27 and 28 are provided with a gap in the front-rear direction L, and are formed to extend in the width direction W. End plate 27 connects one end of side wall 25 to one end of side wall 26, and end plate 28 connects one end of side wall 25 to one end of side wall 26.

[0029] Each side wall 25, side wall 26, end plate 27, and end plate 28 is provided with a fixing part, which will be described later, and each fixing part is fixed to the vehicle body 3.

[0030] Partition walls 22 and 23 are located within the area enclosed by the bottom plate 20 and the peripheral wall 21. Partition wall 22 is positioned adjacent to the end plate 27, and is formed to extend in the width direction W.

[0031] The partition wall 23 is positioned with a gap L in the front-to-back direction relative to the end plate 28. The end plate 28 is also formed to extend in the width direction W.

[0032] The end plate 28 is provided with breathable membranes 19A and 19B. Breathable membranes 19A and 19B are waterproof and breathable membranes, and for example, breathable membranes 19A and 19B are made of Gore-Tex or the like.

[0033] The insulating plate 24 is positioned on the upper surface of the bottom plate 20, between the partition walls 22 and 23. The insulating plate 24 has a plurality of openings 24a. The insulating plate 24 is provided with insulating protectors 24b that close these openings 24a.

[0034] The insulating plate 17 is fixed to the lower surface of the bottom plate 20, and multiple openings 17a are formed in the insulating plate 17.

[0035] Multiple openings 20a are also formed in the base plate 20. The openings 24a, 20a, and 17a are arranged vertically relative to each other.

[0036] The shear panel 18 is positioned below the insulating plate 17, and its outer edge is fixed to the underside of the base plate 20. The shear panel 18 is formed to cover both the insulating plate 17 and the underside of the base plate 20.

[0037] The energy storage module 11 is located on the upper surface of the insulating plate 24. The electrical equipment 13 is located between the partition wall 23 and the end plate 28.

[0038] The energy storage module 11 includes a plurality of energy storage cells 29. The plurality of energy storage cells 29 are arranged with spacing in the front-to-back direction L and with spacing in the width direction W. The energy storage cells 29 may be made up of nickel-metal hydride batteries or lithium-ion batteries, or they may be made up of energy storage elements such as capacitors.

[0039] Figure 3 is a perspective view showing a storage cell 29. The storage cell 29 includes a cell case 4 and an electrode body 5 housed within the cell case 4. The cell case 4 includes a bottom plate, and a smoke exhaust valve 6 is formed on the bottom plate of the cell case 4. Each storage cell 29 is arranged such that the smoke exhaust valve 6 is located above the opening 24a of the insulating plate 24 shown in Figure 2.

[0040] Figure 4 is a plan view showing the cooling device 12, etc., and Figure 5 is a perspective view showing the cooling device 12. Note that the energy storage cells 29, etc., are not shown in Figure 5.

[0041] Referring to Figures 4 and 5, the cooling device 12 includes a heat exchanger 30, a refrigerant pipe 31, and an insulating member 40. The heat exchanger 30 includes a plurality of heat exchange plates 32 and a heat exchange plate 33.

[0042] Multiple heat exchange plates 32 are arranged with a gap between them in the front-to-back direction L. Each heat exchange plate 32 is arranged to extend in the width direction W.

[0043] Between adjacent heat exchange plates 32 in the front-to-back direction L, multiple energy storage cells 29 are arranged in the width direction W. Figure 6 is a cross-sectional view showing the heat exchange plate 32. As shown in Figure 6, multiple refrigerant flow paths 32a are formed in the heat exchange plate 32, spaced apart in the vertical direction H.

[0044] Returning to Figures 4 and 5, the refrigerant pipe 31 is located inside the housing case 10 and includes a supply pipe 35 and a discharge pipe 36. The refrigerant pipe 31 includes a supply pipe 35 and a discharge pipe 36.

[0045] The supply pipe 35 is connected to the supply section 34A, which is inserted into an insertion hole formed in the end plate 27 and is fixed to the end plate 27.

[0046] The supply pipe 35 includes the main supply pipe 37A, the main supply pipe 37B, and the branch pipes 37C, 37D, and 37E.

[0047] The main supply pipe 37A is positioned between the partition wall 22 and the end plate 27, and is positioned to extend in the width direction W. The main supply pipe 37A is formed to extend toward the side wall 25.

[0048] The main supply pipe 37B is connected to the end of the main supply pipe 37A and is formed to extend in the front-rear direction L along the side wall 25.

[0049] Each branch pipe 37C, 37D, and 37E is positioned below the main supply pipe 37B and connected to the main supply pipe 37B. The branch pipes 37C, 37D, and 37E are spaced apart in the front-to-back direction L.

[0050] Furthermore, the connection points between the main supply pipe 37B and each branch pipe 37C, 37D, and 37E are provided with a gap in the front-to-back direction L.

[0051] Multiple heat exchange plates 32, spaced apart in the front-to-back direction L, are connected to branch pipe 37C. Similarly, multiple heat exchange plates 32, spaced apart in the front-to-back direction L, are also connected to branch pipes 37D and 37E.

[0052] A heat exchange plate 33 is connected to the end of the main supply pipe 37B on the end plate 28 side. The heat exchange plate 33 is located on the upper surface of the bottom plate 20, in the portion between the partition wall 23 and the end plate 28. An insulating plate is placed between the heat exchange plate 33 and the bottom plate 20. Electrical equipment 13 is placed on the upper surface of the heat exchange plate 33. The electrical equipment 13 includes, for example, a battery ECU and a junction box.

[0053] The discharge pipe 36 includes a main discharge pipe 38A, a main discharge pipe 38B, and branch pipes 38C, 38D, and 38E.

[0054] The discharge pipe 36 is connected to the discharge section 34B, which is inserted into an insertion hole formed in the end plate 27 and fixed to the end plate 27. The insertion holes 39A and 39B are formed with a gap between them in the width direction W.

[0055] The main discharge pipe 38A is positioned between the partition wall 22 and the end plate 27, is positioned to extend in the width direction W, and is formed to extend toward the side wall 26.

[0056] The main discharge pipe 38B is connected to the end of the main discharge pipe 38B and is formed to extend along the side wall 26.

[0057] Each branch pipe 38C, 38D, and 38E is positioned below the main discharge pipe 38B and connected to the main supply pipe 37B. The branch pipes 38C, 38D, and 38E are spaced apart in the front-to-back direction L.

[0058] Multiple heat exchange plates 32, spaced apart in the front-to-back direction L, are connected to the branch pipe 38C. Similarly, multiple heat exchange plates 32, spaced apart in the front-to-back direction L, are also connected to the branch pipes 38D and 38E. A heat exchange plate 33 is connected to the end of the main discharge pipe 38B on the end plate 28 side.

[0059] The thermal insulation member 40 includes thermal insulation members 40A, 40B, 40C, 40D, and 40E, and thermal insulation members 41A, 41B, 41C, 41D, and 41E.

[0060] The heat insulating member 40A covers a portion of the main supply pipe 37A. On the other hand, a portion of the main supply pipe 37A is exposed from the heat insulating member 40A. As a result, the main supply pipe 37A has an exposed portion 43 that is exposed inside the housing case 10.

[0061] The heat insulating member 40A is formed to cover the connection portion between the main supply pipe 37A and the main discharge pipe 38B of the main supply pipe 37A.

[0062] Insulation member 40B covers the main supply pipe 37B. Similarly, insulation members 40C, 40D, and 40E cover the branch pipes 37C, 37D, and 37E. Insulation members 41A and 41B cover the main discharge pipes 38A and 38B, and insulation members 41C, 41D, and 41E cover the branch pipes 38C, 38D, and 38E.

[0063] As shown in Figure 4, a fixing portion 75A is formed on the outer surface of the side wall 25, and similarly, a fixing portion 76A is formed on the outer surface of the side wall 26.

[0064] Fixing portions 77A and 77B are formed on the outer surface of the end plate 27, and fixing portions 78A and 78B are formed on the outer surface of the end plate 28.

[0065] The fixing parts 77A and 77B are fixed to the vehicle body 3 by fastening members. For example, the vehicle body 3 includes side sills arranged at intervals in the width direction W, cross members connecting the side sills, and a floor panel, and the fixing parts 77A and 77B are fixed to the cross members. Alternatively, the fixing parts 77A and 77B may be fixed to the floor panel.

[0066] The fixing portion 75A is formed to protrude in the width direction W from the outer surface of the side wall 25. The fixing portion 76A is formed to protrude in the width direction W from the outer surface of the side wall portion 26. The fixing portions 75A and 76A are fixed to the side sill of the vehicle body 3 by fastening members.

[0067] The energy storage device 2 configured as described above will now be explained. In Figure 2, when the energy storage module 11 is cooled, refrigerant C is supplied to the cooling device 12. Then, in Figure 3, refrigerant C is supplied from the supply unit 34A to the supply pipe 35. Specifically, refrigerant C is supplied to the main supply pipe 37A. After that, refrigerant C enters the main supply pipe 37B. Then, a portion of the refrigerant C that enters the main supply pipe 37A enters the branch pipes 37C, 37D, and 37E.

[0068] The refrigerant C that enters the branch pipes 37C, 37D, and 37E is supplied to the multiple heat exchange plates 32 connected to the branch pipes 37C, 37D, and 37E.

[0069] The refrigerant C is supplied to multiple heat exchange plates 32, thereby cooling the energy storage cells 29 placed between the heat exchange plates 32. At the same time, the refrigerant C circulating within the heat exchange plates 32 is warmed by the heat from the energy storage cells 29.

[0070] Multiple heat exchange plates 32 are connected to branch pipes 38C, 38D, and 38E, and the refrigerant C heated within the heat exchange plates 32 enters the branch pipes 38C, 38D, and 38E.

[0071] The branch pipes 38C, 38D, and 38E are connected to the main discharge pipe 38A, and the refrigerant C passes through the main discharge pipe 38A and is discharged to the outside of the housing case 10 from the discharge section 34B. The discharge section 34B is connected to a radiator or the like (not shown), and the refrigerant C is cooled by the radiator or the like. The cooled refrigerant C is then supplied back to the supply section 34A.

[0072] Furthermore, a heat exchange plate 33 is connected to the end of the main discharge pipe 38A, and the electrical equipment 13 is cooled by the heat exchange plate 33. The heat exchange plate 33 is connected to the end of the main discharge pipe 38B, and the refrigerant C enters the main discharge pipe 38B.

[0073] The heat exchange plate 32 is positioned between the multiple energy storage cells 29, facing the longitudinal (width direction W) side surfaces (hereinafter referred to as "long side surfaces") of the multiple energy storage cells 29. The heat exchange plate 32 extends along the longitudinal (width direction W) of the long side surfaces of the multiple energy storage cells 29. The energy storage cells 29 and the heat exchange plate 32 are bonded together with an adhesive. As the adhesive, for example, a known structural adhesive with relatively high thermal conductivity, such as an acrylic adhesive, epoxy adhesive, or urethane adhesive, may be used.

[0074] In the energy storage device 2 configured as described above, expansion and contraction occur in each energy storage cell 29 when charging and discharging occur. The deformation of the energy storage cells 29 when expansion and contraction occur is absorbed by the deformation of the heat exchange plate 32 provided between the energy storage cells 29. As a result, the energy storage device 2 as a whole maintains a constant shape.

[0075] However, if the deformation of the heat exchange plate 32 cannot keep up with the increase in expansion and contraction of the energy storage cell 29, the adhesion between the energy storage cell 29 and the heat exchange plate 32 may decrease, potentially reducing heat exchange performance, including cooling performance. While it is conceivable to uniformly increase the adhesive strength between the heat exchange plate 32 and the energy storage cell 29, this could result in areas with excessive adhesive strength, potentially worsening recyclability (ease of disassembly and removal of the energy storage cell 29 and heat exchange plate 32).

[0076] Therefore, in this embodiment, the adhesive strength of the central part of the long side of the energy storage cell 29 in the short direction (vertical direction H) is greater than the adhesive strength of the end of the long side in the short direction.

[0077] In this configuration, the adhesive strength at the center of the long side of the energy storage cell 29 in the short direction is greater than the adhesive strength at the ends in the short direction. Therefore, even if a force acts on the center that causes the distance between the energy storage cell 29 and the heat exchange plate 32 to become relatively larger during contraction or expansion of the energy storage cell 29, the distance between the energy storage cell 29 and the heat exchange plate 32 is maintained by the adhesive with high adhesive strength. This suppresses a decrease in the adhesion between the energy storage cell 29 and the heat exchange plate 32.

[0078] Referring to Figures 7 and 8, the specific configuration of the heat exchange plate 32 of the energy storage device according to this embodiment will be described.

[0079] Figure 7 shows an example of the configuration of the heat exchange plate 32. As shown in Figure 7, the heat exchange plate 32 has a rectangular shape when viewed from the front-to-back direction L. The heat exchange plate 32 has a hollow interior. Multiple partition walls are provided inside the heat exchange plate 32. Multiple refrigerant flow paths are formed inside the heat exchange plate 32 by the multiple partition walls. A connection part 50 connected to a supply pipe 35 is provided at one end of the heat exchange plate 32 in the width direction W. A connection part 52 connected to a discharge pipe 36 together with the heat exchange plate 32 is provided at the other end in the width direction W. Therefore, the refrigerant supplied from the connection part 50 to the supply pipe 35 flows through the flow paths inside the heat exchange plate 32 from one end to the other end, and is then discharged from the connection part 52 to the discharge pipe 36.

[0080] The heat exchange plate 32 is formed from, for example, a highly thermally conductive metal such as aluminum or a resin. The heat exchange plate 32 is manufactured, for example, by attaching connecting parts 50 and 52 to a hollow aluminum member formed by extrusion. In this embodiment, the heat exchange plate 32 is configured such that the adhesive strength of the adhesive applied to the central part 32c (the long dashed line frame in the center of the vertical direction H) is greater than the adhesive strength of the adhesive applied to the end part 32b (the short dashed line frame on the upper side of the vertical direction H) and the end part 32d (the dashed line frame on the lower side of the vertical direction H), respectively.

[0081] More specifically, in this embodiment, the energy storage device 2 uses an adhesive that has a higher adhesive strength when applied to the central portion 32c in the vertical direction H than when applied to the ends 32b and 32d in the vertical direction H. For example, of two adhesives with different adhesive strengths, the adhesive with the higher adhesive strength is applied to the central portion 32c, and the adhesive with the lower adhesive strength is applied to the ends 32b and 32d. The adhesive strength of the adhesive applied to the central portion 32c is such that it can maintain close contact with the energy storage cell 29 even if the heat exchange plate 32 or the energy storage cell 29 is deformed.

[0082] Figure 8 shows an example of a cross-section of the heat exchange plate 32, adhesive, and energy storage cell 29. Figure 8 shows the A-A' cross-section of the heat exchange plate 32 in Figure 7. As shown in Figure 8, multiple flow channels 32a are formed inside the heat exchange plate 32 in the central part 32c and the ends 32b and 32d. The flow channels 32a are formed by partition walls 32e and 32f. In Figure 8, three flow channels 32a are formed at each of the ends 32b and 32d. Also, four flow channels 32a are formed in the central part 32c.

[0083] Between the heat exchange plate 32 and the energy storage cell 29, an adhesive layer 32w corresponding to the end portion 32b, an adhesive layer 32x corresponding to the central portion 32c, and an adhesive layer 32y corresponding to the end portion 32d are formed. By using different adhesives for the central portion 32c and the ends 32b and 32d, the adhesive strength between the heat exchange plate 32 and the energy storage cell 29 in the central portion 32c is configured to be greater than the adhesive strength between the heat exchange plate 32 and the energy storage cell 29 in each of the ends 32b and 32d.

[0084] When the energy storage cell 29 is charged or discharged, the energy storage cell 29 expands or contracts. For example, when the energy storage cell 29 expands, a compressive force acts on the bonded heat exchange plate 32 along the front-to-back direction L. This compressive force is greater near the center of the electrode body of the energy storage cell 29 in the vertical direction H than near the upper or lower end, so a greater force acts on the central part 32c of the heat exchange plate 32 than on the ends 32b and 32d. When the force acting on the central part 32c exceeds the elastic limit, the heat exchange plate 32 undergoes plastic deformation. Subsequently, when contraction occurs in the energy storage cell 29, the amount of contraction in the central part 32c is greater than the amount of contraction in the ends 32b and 32d. Therefore, in the central part 32c, deformation occurs while maintaining close contact with the energy storage cell 29 due to the adhesive with high adhesive strength. Because the close contact between the central portion 32c and the energy storage cell 29 is maintained, the end portions 32b and 32d, which use adhesive with lower adhesive strength than the central portion 32c, will also deform while maintaining close contact with the energy storage cell 29.

[0085] As described above, in the energy storage device 2 according to this embodiment, the adhesive strength at the central portion 32c is configured to be greater than the adhesive strength at the ends 32b and 32d. Therefore, even when a force acts in a direction that relatively increases the distance between the energy storage cell 29 and the heat exchange plate 32 during contraction or expansion of the energy storage cell 29, the distance between the energy storage cell 29 and the heat exchange plate 32 is maintained by the adhesive with high adhesive strength. This makes it possible to suppress a decrease in adhesion between the energy storage cell 29 and the heat exchange plate 32 at both the central portion 32c and the ends 32b and 32d. Thus, it is possible to provide an energy storage device that suppresses a decrease in adhesion with the heat exchanger when the energy storage element deforms.

[0086] Furthermore, since an adhesive with higher adhesive strength than the adhesive used in the ends 32b and 32d is used to bond the energy storage cell 29 and the heat exchange plate 32 in the central part 32c, compared to the case where the adhesive used in the central part 32c is also used in the ends 32b and 32d, disassembly of the energy storage device 2 (especially the disassembly and removal of the energy storage cell 29 and the heat exchange plate 32) through recycling processes becomes easier, thus improving recyclability.

[0087] The following describes some variations. In the above-described embodiment, the energy storage cell 29 and the heat exchange plate 32 were described as being bonded together with an adhesive. However, the energy storage cell 29 and the heat exchange plate 32 may be bonded together by means other than an adhesive. For example, an adhesive layer may be provided on the surface of an insulating member placed between the energy storage cell 29 and the heat exchange plate 32.

[0088] Furthermore, in the above-described embodiment, the adhesive strength of the adhesive applied to the central portion 32c is made greater than that of the adhesive applied to the ends 32b and 32d by using adhesives with different adhesive strengths for the central portion 32c and the ends 32b and 32d. However, it is not limited to using different adhesives in order to achieve different adhesive strengths. For example, the central portion 32c of the heat exchange plate 32 may be subjected to a surface treatment.

[0089] Figure 9 shows an example of a cross-section of the heat exchange plate 32, adhesive, and energy storage cell 29 in a modified example. Figure 9 differs from Figure 8 in that the same adhesive is uniformly applied to the central portion 32c and the ends 32b and 32d, and that the central portion 32c is surface-treated. The other components of Figure 9 are the same as those in Figure 8, so a detailed explanation will not be repeated. As shown in Figure 9, the central portion 32c may be surface-treated so that a surface treatment 32x' is formed in the portion corresponding to the central portion 32c of the heat exchange plate 32.

[0090] The surface treatment is not particularly limited as long as it is such that the adhesive strength of the adhesive in the central part 32c is higher than the adhesive strength of the adhesive in the edges 32b and 32d. For example, a primer treatment or a treatment that makes the surface roughness of the central part 32c greater than that of the edges 32b and 32d (such as blasting) may be applied, or a treatment that removes the oxide film from the central part 32c may be applied.

[0091] In Figure 9, the case in which the central portion 32c of the heat exchange plate 32 is surface-treated is shown as an example. However, for example, the same surface treatment may also be applied to the surface of the energy storage cell 29 facing the central portion 32c of the heat exchange plate 32.

[0092] In this way, even when the same adhesive is uniformly applied to the surface of the heat exchange plate 32 facing the energy storage cell 29, forming an adhesive layer 32w', the adhesive strength of the adhesive in the central part 32c can be made higher than the adhesive strength of the adhesive at the ends 32b and 32d. Furthermore, compared to using two types of adhesives with different adhesive strengths, the increase in production costs can be suppressed.

[0093] Furthermore, in the above-described embodiment, it was explained that by using adhesives with different adhesive strengths in the central portion 32c and the ends 32b, 32d, the adhesive strength of the adhesive applied to the central portion 32c is made greater than the adhesive strength of the adhesive applied to the ends 32b, 32d. However, it is not limited to using different adhesives in order to make the adhesive strengths different. For example, the energy storage device 2 may be configured such that the adhesive application area per unit area of ​​the heat exchange plate 32 in the central portion 32c in the vertical direction H is greater than the adhesive application area per unit area of ​​the heat exchange plate 32 in the ends 32b, 32d in the vertical direction H.

[0094] For example, in the central portion 32c, adhesive may be applied to a first proportion of the central portion 32c (for example, the entire surface), while in the end portions 32b and 32d, adhesive may be applied to an area corresponding to a portion of the entire surface (a predetermined proportion such as 60% or 70%), and the adhesive may not be applied to the other areas.

[0095] Figure 10 shows another example of a cross-section of the heat exchange plate 32, adhesive, and energy storage cell 29 in a modified example. Figure 10 differs from Figure 8 in that the adhesive is applied to the entire surface of the central part 32c, while it is applied only to the ends 32b and 32d. The other configurations in Figure 10 are the same as those in Figure 8, so a detailed explanation will not be repeated. As shown in Figure 10, in the portion of the heat exchange plate 32 corresponding to the central part 32c, an adhesive layer 32x'' is formed over the entire surface, while in the portion corresponding to the end 32b, multiple adhesive layers 32w'' are formed (for example, 3) with predetermined spacing in the vertical direction H and adhesive applied along the width direction W. Furthermore, in the portion corresponding to the end 32d, multiple adhesive layers 32y'' are formed (for example, 3) with predetermined spacing in the vertical direction H and adhesive applied along the width direction W. The predetermined intervals should be set according to the required adhesive strength at the ends 32b and 32d, and the intervals at ends 32b and 32d may be different. Also, the lengths H in the vertical direction of the adhesive layer 32w'' and adhesive layer 32y'' may be the same or different.

[0096] In this way, the adhesive application area per unit area in the central section 32c can be made larger than the adhesive application area per unit area in the end sections 32b and 32d. As a result, even when the same adhesive is used on the surface of the heat exchange plate 32 facing the energy storage cell 29, the adhesive strength of the adhesive in the central section 32c can be made higher than the adhesive strength of the adhesive in the end sections 32b and 32d. Furthermore, compared to the case where two types of adhesives with different adhesive strengths are used, the increase in production costs can be suppressed.

[0097] In this modified example, the case in which multiple adhesive layers 32w'' are formed along the width direction W was described as an example. However, for example, multiple adhesive layers formed along the vertical direction H at the ends 32b, 32d may be arranged at predetermined intervals along the width direction W.

[0098] Furthermore, in the above-described embodiment, the adhesive strength of the central portion 32c was described as being greater than the adhesive strength of the ends 32b and 32d. However, for example, in addition to that, the Young's modulus of the central portion 32c of the heat exchange plate 32 may be made smaller than the Young's modulus of the ends 32b and 32d.

[0099] The Young's modulus of the central portion 32c represents the ratio of strain (deformation) to stress in the longitudinal direction L at the central portion 32c of the heat exchange plate 32. Figure 11 shows an example of the Young's modulus of the central portion 32c and the Young's modulus of the ends 32b and 32d in the elastic region. The vertical axis of Figure 11 represents stress. The horizontal axis of Figure 11 represents strain (deformation). LN1 in Figure 11 shows an example of the Young's modulus of the central portion 32c. LN2 in Figure 11 shows an example of the Young's modulus of the end 32b. The Young's modulus of the end 32d is the same value as the Young's modulus of the end 32b. As shown in LN1 and LN2 in Figure 11, the heat exchange plate 32c may be configured such that the Young's modulus of the central portion 32c is smaller than that of the ends 32b and 32d.

[0100] For example, the adhesive constituting the adhesive layer 32x of the heat exchange plate 32 in Figure 8 may be selected such that the adhesive applied to the central portion 32c and the adhesive applied to the ends 32b and 32d have greater adhesive strength and a smaller Young's modulus than the adhesives constituting the adhesive layers 32w and 32y. The Young's modulus of the adhesive can be changed, for example, using known techniques, and may be changed by the type, material, and amount of the adhesive.

[0101] In this way, in addition to having different adhesive strengths in the central part 32c and the ends 32b and 32d, the Young's modulus of the central part 32c of the heat exchange plate 32 can be made smaller than that of the ends 32b and 32d. Therefore, the deformation of the central part 32c of the heat exchange plate 32 in response to the contraction and expansion of the energy storage cell 29 is relatively tolerable compared to the deformation of the ends 32b and 32d. As a result, the close contact between the central part 32c of the heat exchange plate 32 and the energy storage cell 29 can be maintained. This further suppresses the decrease in adhesion between the energy storage cell 29 and the heat exchange plate 32.

[0102] Furthermore, the configuration that makes the Young's modulus of the central portion 32c of the heat exchange plate 32 smaller than that of the ends 32c and 32d is not limited to the selection of adhesive. For example, the distance between the partition walls may be varied between the central portion 32c and the ends 32b and 32d.

[0103] Figure 12 shows an example of a cross-section of the heat exchange plate 32 in a modified example. As shown in Figure 12, multiple flow channels 32a are formed at the ends 32b and 32d of the heat exchange plate 32. In Figure 12, three flow channels 32a are formed at each of the ends 32b and 32d. The flow channels 32a are formed by partition walls 32e and 32f.

[0104] Similarly, multiple flow channels 32g are formed in the central part 32c of the heat exchange plate 32 in the vertical direction H. In Figure 12, two flow channels 32g are formed. The flow channels 32g are formed by partition walls 32h and 32i.

[0105] Furthermore, the distance between partition wall 32h and partition wall 32i in the flow path 32g of the central portion 32c is configured to be greater than the distance between partition wall 32e and partition wall 32f in the flow path 32a of the ends 32b and 32d. This configuration makes it possible to make the Young's modulus of the central portion 32c of the heat exchange plate 32 smaller than that of the ends 32b and 32d.

[0106] Furthermore, in Figure 12, we have explained as an example the case in which end 32b and end 32d have regions of the same area, and each has three flow channels 32a. However, regions with different areas may be set for end 32b and end 32d.

[0107] Furthermore, in the above-described embodiment, a case in which multiple channels of the same size are provided in the central section 32c and the end sections 32b and 32d was explained as an example. However, it is sufficient that the distance between the partition walls in the end sections 32b and 32d is smaller than the distance between the partition walls in the central section 32c, and channels of different sizes may be provided.

[0108] Figure 13 shows another example of the cross-section of the heat exchange plate 32 in a modified example. As shown in Figure 13, an area smaller in area than that of the end 32d may be set as the end 32b. Furthermore, the first distance between the partition wall 32k and partition wall 32l of the flow path 32j in the central part 32c, and the second distance between the partition wall 32h and partition wall 32i of the flow path 32g in the central part 32c, may both be greater than the third distance between the partition wall 32e and partition wall 32f of the flow path 32a in the ends 32b and 32d, and the first distance and the second distance may be different. Even in this way, the Young's modulus of the central part 32c of the heat exchange plate 32 can be made smaller than the Young's modulus of the ends 32b and 32d.

[0109] Furthermore, although Figure 12 illustrates an example where multiple channels are formed in the central portion 32c, a single channel may also be formed in the central portion 32c.

[0110] Figure 14 shows yet another example of a cross-section of the heat exchange plate 32 in a modified example. As shown in Figure 14, a single channel 32m may be formed in the central portion 32c. The channel 32m is formed by partition walls 32n and 32o. The distance between partition walls 32n and 32o is greater than the distance between partition walls 32e and 32f of the channel 32a. Three channels 32a are formed at each of the ends 32b and 32d. In this way, the Young's modulus of the central portion 32c of the heat exchange plate 32 can be made smaller than the Young's modulus of the ends 32b and 32d.

[0111] Figure 15 shows another example of a cross-section of the heat exchange plate 32 in a modified example. As shown in Figure 15, a single channel 32p may be formed in the central portion 32c. The channel 32p is formed by partition walls 32q and 32r. The distance between partition walls 32q and 32r is greater than the distance between partition walls 32e and 32f of the channel 32a. Three channels 32a are formed at each of the ends 32b and 32d. In this way, the Young's modulus of the central portion 32c of the heat exchange plate 32 can be made smaller than the Young's modulus of the ends 32b and 32d.

[0112] Furthermore, in Figure 12, an example was shown in which the heat exchange plate 32 is configured such that the distance between partition walls in the central section 32c is greater than the distance between partition walls at the ends 32b and 32d. However, the thickness of the partition walls in the central section 32c may be smaller than the thickness of the partition walls at the ends 32b and 32d.

[0113] Figure 16 shows an example of a cross-section of the heat exchange plate 32 in another modified example. As shown in Figure 16, multiple channels are formed at the ends 32b and 32d of the heat exchange plate 32, including partition walls formed by wall surfaces 32s and 32t. Similarly, multiple channels are formed at the central part 32c of the heat exchange plate 32, including partition walls formed by wall surfaces 32u and 32v. The thickness of the partition wall formed by wall surfaces 32u and 32v is smaller than the thickness of the partition wall formed by wall surfaces 32s and 32t. In this way, the Young's modulus of the central part 32c of the heat exchange plate 32 can be made smaller than the Young's modulus of the ends 32b and 32d.

[0114] Furthermore, in the above-described embodiment, one example was described in which the center of the central portion 32c coincides with the center line in the vertical direction H of the heat exchange plate 32, but the method of setting the central portion 32c is not limited to the above-described method. For example, the central portion 32c of the heat exchange plate 32 may be positioned to overlap with the center of the electrode body 5 in the vertical direction (vertical direction H) of the electrode body 5 housed in the energy storage cell 29 when viewed from a first direction perpendicular to both the longitudinal direction (width direction W) and the short direction (vertical direction H) of the heat exchanger.

[0115] Figure 17 shows an example of a cross-section of the heat exchange plate 32, energy storage cell 29, and electrode body 5 in a modified example. As shown in Figure 17, the electrode body 5 is housed in the energy storage cell 29 adjacent to the heat exchange plate 32. The first direction in Figure 17 indicates a direction perpendicular to both the width direction W and the vertical direction H. The dashed line in Figure 14 indicates the centerline of the electrode body 5 in the vertical direction H. In Figure 17, the centerline of the electrode body 5 and the centerline of the central part 32c are arranged to overlap.

[0116] In this configuration, the portion of the energy storage cell 29 with a large amount of contraction overlaps with the central portion 32c, which allows relative deformation to the ends 32b and 32d. Furthermore, the adhesive applied to the central portion 32c has greater adhesive strength than the adhesive applied to the ends 32b and 32d, thus suppressing a decrease in the adhesion between the energy storage cell 29 and the heat exchange plate 32. In Figure 17, the case in which the center line of the electrode body 5 coincides with the center line of the central portion 32c is explained as an example. However, it is sufficient that the central portion of the electrode body 5 and the central portion 32c overlap, and it is not limited to the two center lines coinciding.

[0117] Furthermore, in Figure 12, the partition wall was explained as an example of a case where it is formed by a plane parallel to a plane formed by the front-to-back direction L and the width direction W. However, the partition wall may also be formed by a plane having a predetermined angle with respect to the plane formed by the front-to-back direction L and the width direction W, or by a plane in the vertical direction H and the width direction W.

[0118] Figure 18 shows an example of a cross-section of the heat exchange plate 32 in yet another modified example. As shown in Figure 18, multiple channels 32a' are formed in the central part 32c and the ends 32b,32d of the heat exchange plate 32. The channels 32a' are formed by partition walls 32e' and 32f'. The wall surface of partition wall 32e' is formed by a plane having a predetermined angle with respect to a plane formed by the front-to-back direction L and the width direction W. The wall surface of partition wall 32f' is formed by a plane parallel to the wall surface of partition wall 32e'. Therefore, as shown in Figure 18, the cross-section of the channels 32a' is a parallelogram.

[0119] Furthermore, the above-mentioned modifications may be implemented by combining all or part of them as appropriate. 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 foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0120] 1 Vehicle, 2 Energy storage device, 3 Vehicle body, 4 Cell case, 5 Electrode body, 6 Smoke exhaust valve, 10 Housing case, 11 Energy storage module, 12 Cooling device, 13 Electrical equipment, 15 Lower case, 16 Upper case, 17 Insulating plate, 17a Opening, 18 Shear panel, 19A, 19B Breathing membrane, 20 Bottom plate, 20a Opening, 21 Peripheral wall, 22, 23 Partition wall, 24 Insulating plate, 24a Opening, 24b Insulating protector, 25, 26 Side wall, 27, 28 End plate, 29 Energy storage cell, 30 Heat exchanger, 31 Refrigerant pipe, 32, 33 Heat exchange plate, 32b, 32d End, 32c Central part.

Claims

1. Multiple energy storage elements, The system comprises a heat exchanger positioned between the plurality of energy storage elements, facing the long sides of the plurality of energy storage elements, and extending in the longitudinal direction of the long sides, The energy storage element and the heat exchanger are bonded together. An energy storage device in which the adhesive strength of the central part in the short direction of the long side surface is greater than the adhesive strength of the end part in the short direction of the long side surface.

2. The energy storage device according to claim 1, wherein the heat exchanger has a surface treatment applied to the central part of the short side of the long side.

3. The energy storage element and the heat exchanger are bonded together with an adhesive. The energy storage device according to claim 1, wherein the area of ​​adhesive applied per unit area of ​​the heat exchanger in the central part in the short direction is greater than the area of ​​adhesive applied per unit area of ​​the heat exchanger at the ends in the short direction.

4. The energy storage device according to claim 1, wherein the adhesive strength of the adhesive placed in the central part in the short direction is greater than the adhesive strength of the adhesive placed at the end in the short direction.

5. The energy storage device according to claim 1, wherein the Young's modulus of the central part in the short direction of the heat exchanger is smaller than the Young's modulus of the end in the short direction.

6. The energy storage device according to claim 1, wherein the central portion of the heat exchanger is positioned to overlap with the central portion of the electrode body housed within the energy storage element when viewed from a first direction perpendicular to both the longitudinal and transverse directions.

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