Secondary battery

Abstract

The utility model relates to a secondary battery, it has: the lamination is by the lamination multiple battery unit constitutes, the housing component is by the film constitutes, the housing lamination, and the heat transfer material is arranged in the inside of housing component, is clamped by the side of lamination and housing component, in the length range of heat transfer material in the lamination direction of lamination, and the heat resistance of heat transfer material is lower than the heat resistance of housing component, adopt the utility model, can inhibit the generation of temperature gradient in lamination.

Description

Technical Field

[0001] This utility model relates to a secondary battery. Background Technology

[0002] Japan Special Open 2023 Publication No. 177537 discloses a battery pack consisting of alternating layers of secondary batteries and coolers.

[0003] In a secondary battery composed of a stack of multiple battery cells, heat is difficult to transfer along the stacking direction. Therefore, during use, a temperature gradient easily occurs along the stacking direction within the stack, causing the interior of the stack to become hot. Consequently, this can sometimes lead to battery degradation and reduced performance. Utility Model Content

[0004] This invention provides a secondary battery capable of suppressing the occurrence of temperature gradients within a laminate.

[0005] The first technical solution is a secondary battery comprising: a laminate composed of multiple stacked battery cells; a housing member made of a membrane housing the laminate; and a heat transfer material disposed inside the housing member and held between the sides of the laminate and the housing member. Within the length of the heat transfer material along the stacking direction of the laminate, the thermal resistance of the heat transfer material is lower than the thermal resistance of the housing member.

[0006] In the aforementioned secondary battery, the thermal resistance of the heat transfer material is lower than that of the housing components along its length in the stacking direction. Therefore, during the use of the secondary battery, heat transferred from the stack to the heat transfer material is efficiently conducted along the stacking direction by the heat transfer material. As a result, the occurrence of temperature gradients within the stack can be suppressed.

[0007] The second technical solution, based on the first technical solution, further includes a sealing component. The sealing component is disposed inside the receiving component and covers the side surface of the laminate. The heat transfer material covers the side surface of the sealing component and the outer periphery of the electrode layer constituting the end face of the laminate.

[0008] As a result, heat can be easily transferred from the electrode layer to the heat transfer material, thus improving heat dissipation.

[0009] The third technical solution, based on the first or second technical solution, further includes a sealing component and a metal plate. The sealing component is disposed inside the receiving component and covers the side surface of the laminate. The metal plate is disposed inside the receiving component and is in contact with the electrode layer constituting the end face of the laminate and the end face of the sealing component. The heat transfer material covers the side surface of the sealing component. The metal plate is in contact with the heat transfer material. The receiving component has a conductive film portion and an insulating film portion. The conductive film portion is disposed in the portion overlapping the electrode layer when viewed along the lamination direction and is in contact with the metal plate. The insulating film portion covers the side surface of the heat transfer material and is connected to the conductive film portion.

[0010] As a result, heat can be easily transferred from the heat transfer material through the metal plate to the conductor film, thus improving heat dissipation.

[0011] The fourth technical solution is based on any of the first to third technical solutions, wherein the metal plate has a first part and a second part, the first part is in contact with the end face of the sealing member, the second part is bent into a convex shape toward the end face of the electrode layer and is in contact with the first part at a position away from the heat transfer material; the secondary battery also has a conductive adhesive for bonding the second part to the end face of the electrode layer.

[0012] Therefore, when the conductive adhesive softens due to the heat generated by the laminate, the second part deforms away from the laminate, and the connection between the second part and the laminate is released. Thus, the current in the laminate can be stopped.

[0013] The fifth technical solution is based on any of the first to fourth technical solutions, wherein, in the stacking direction, the thermal conductivity of the heat transfer material is higher than that of the laminate.

[0014] This invention can suppress the occurrence of temperature gradients within laminates. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the battery pack.

[0016] Figure 2 This is a schematic diagram of the secondary battery in Example 1.

[0017] Figure 3 This is an explanatory diagram of a stacked structure.

[0018] Figure 4 This is a schematic diagram of the secondary battery in Example 2.

[0019] Figure 5 This is a schematic diagram of the secondary battery in Example 3. Detailed Implementation

[0020] The embodiments of this utility model are described below.

[0021] Example 1 Figure 1 The battery pack 200 shown is, for example, mounted in an electric vehicle. The battery pack 200 has multiple secondary batteries 100 stacked in the z-direction. The multiple secondary batteries 100 are stacked in the z-direction with a cooler 50 and a current collector 52 in between. The cooler 50 and the current collector 52 are alternately arranged in the z-direction. The cooler 50 is held vertically by two secondary batteries 100. The current collector 52 is also held vertically by two secondary batteries 100. Therefore, one of the upper and lower surfaces of each secondary battery 100 is in contact with the cooler 50, and the other of the upper and lower surfaces is in contact with the current collector 52. The cooler 50 is provided with a flow path for refrigerant flow. The cooler 50 cools adjacent secondary batteries 100. Furthermore, the cooler 50 is made of a conductor, electrically connecting the upper and lower secondary batteries 100. The current collector 52 is made of a conductive material, electrically connecting the upper and lower secondary batteries 100. Examples of materials for the current collector 52 include aluminum and copper.

[0022] Each secondary battery 100 has a laminate 12. For example... Figure 2 As shown, the stack 12 is composed of a plurality of battery cells 10 stacked in the z-direction. Each battery cell 10 has a generally plate-like shape extending in the x and y directions and is a rechargeable and dischargeable secondary battery cell. Each battery cell 10 is, for example, a lithium-ion battery cell or an all-solid-state battery cell.

[0023] like Figure 3 As shown, each battery cell 10 has multiple electrode layers 14 and a cell body 16. The electrode layers 14 are the electrodes of the secondary battery cell. Although not shown, the cell body 16 includes a separator, electrolyte, etc. The cell body 16 is sandwiched between two electrode layers 14. Adjacent battery cells 10 share electrode layers 14. The surface of the battery cell 10 located at the end is formed by the electrode layers 14. Therefore, Figure 2 The upper surface 12b and lower surface 12c of the stack 12 shown are composed of electrode layers 14. Multiple battery cells 10 are connected in series. Therefore, the stack 12 outputs a high voltage between the upper surface 12b and the lower surface 12c.

[0024] like Figure 2 As shown, the secondary battery 100 has a sealing member 22, a heat transfer material 20, and a housing member 30. The housing member 30 houses the laminate 12, the sealing member 22, and the heat transfer material 20. That is, the laminate 12, the sealing member 22, and the heat transfer material 20 are disposed inside the housing member 30.

[0025] The sealing member 22 is made of resin material. The sealing member 22 covers the outer periphery of the laminate 12. That is, the sealing member 22 covers the side surface 12a of the laminate 12.

[0026] The heat transfer material 20 is made of an insulating material with high thermal conductivity. For example, the heat transfer material 20 is made of acrylic resin, silicone resin, polyacrylamide resin, etc. Alternatively, the heat transfer material 20 may also contain ceramic fillers or metal fillers. Furthermore, the heat transfer material 20 can be a filled type or a sheet type. The heat transfer material 20 covers the outer side 22a of the sealing member 22 throughout the range of multiple battery cells 10. The outer side of the heat transfer material 20 is in contact with the housing member 30. That is, the heat transfer material 20 is sandwiched between the side 22a and the housing member 30. The heat transfer material 20 covers the upper surface 22b and the lower surface 22c of the sealing member 22. The heat transfer material 20 covers the outer periphery 14a of the upper surface 12b of the laminate 12. That is, the heat transfer material 20 covers the outer periphery 14a of the electrode layer 14 constituting the upper surface 12b. Similarly, the heat transfer material 20 covers the outer periphery 14b of the lower surface 12c of the laminate 12. That is, the heat transfer material 20 covers the outer periphery 14b of the electrode layer 14 that forms the lower surface 12c. Within the length L1 of the heat transfer material 20 in the z direction, the thermal conductivity of the heat transfer material 20 is higher than that of the laminate 12.

[0027] The housing component 30 has a conductive film portion 34a, a conductive film portion 34b, and an insulating film portion 36. The conductive film portions 34a and 34b are made of a conductive material. Examples of conductive materials for the conductive film portions 34a and 34b include aluminum and copper. The insulating film portion 36 has a structure formed by combining a conductive film 36c (aluminum, etc.) with an insulating film 36d.

[0028] The conductor film portion 34a is disposed in the portion that overlaps with the upper surface 12b (i.e., the electrode layer 14) when viewed along the z-direction. The conductor film portion 34a is in contact with the electrode layer 14. In other words, the conductor film portion 34a is in contact with the upper surface 12b of the laminate 12. The conductor film portion 34a is electrically connected to the laminate 12.

[0029] The conductor film portion 34b is disposed in the portion that overlaps with the lower surface 12c (i.e., the electrode layer 14) when viewed along the z-direction. The conductor film portion 34b is in contact with the electrode layer 14. In other words, the conductor film portion 34b is in contact with the lower surface 12c of the laminate 12. The conductor film portion 34b is electrically connected to the laminate 12.

[0030] The insulating film portion 36 has an upper insulating film portion 36a and a lower insulating film portion 36b. The upper insulating film portion 36a is connected to the outer periphery of the conductor film portion 34a. The upper insulating film portion 36a is insulated from the conductor film portion 34a. The upper insulating film portion 36a is in contact with the upper surface and outer side surface of the heat transfer material 20. The lower insulating film portion 36b is connected to the outer periphery of the conductor film portion 34b. The lower insulating film portion 36b is insulated from the conductor film portion 34b. The lower insulating film portion 36b is in contact with the lower surface and outer side surface of the heat transfer material 20. The outer periphery of the lower insulating film portion 36b is fused to the outer periphery of the upper insulating film portion 36a on the side of the heat transfer material 20. Therefore, the heat transfer material 20 is held by the insulating film portion 36 and the side surface 22a of the sealing member 22.

[0031] Within the length L1 of the heat transfer material 20 in the z-direction, the thermal resistance of the heat transfer material 20 is lower than that of the housing member 30 (in this case, the insulating film portion 36). Furthermore, in the z-direction, the thermal conductivity of the heat transfer material 20 is higher than that of the laminate 12.

[0032] During the charging and discharging of the secondary battery 100, heat is generated in the laminate 12. The cooler 50 is in contact with one end face of the secondary battery 100. Therefore, the portion of the laminate 12 on the cooler 50 side is cooled by the cooler 50. Furthermore, since the thermal conductivity in the z-direction of the laminate 12 is low, heat is not easily transferred in the z-direction within the laminate 12. Therefore, without the heat transfer material 20, a temperature gradient is generated in the z-direction within the laminate 12. That is, the portion of the laminate 12 on the current collector 52 side (the portion opposite to the cooler 50) is difficult to cool and becomes high-temperature. In contrast, the secondary battery 100 of Embodiment 1 has a heat transfer material 20 extending from the outer periphery 14a of the upper surface 12b to the outer periphery 14b of the lower surface 12c. In the z-direction, the thermal conductivity of the heat transfer material 20 is higher than that of the laminate 12. Furthermore, within the length L1 of the heat transfer material 20 in the z-direction, the thermal resistance of the heat transfer material 20 is lower than that of the housing member 30 (here, the insulating film portion 36). Therefore, the heat generated in the laminate 12 is efficiently conducted to the cooler 50 in the z-direction through the heat transfer material 20. As a result, the occurrence of temperature gradients within the laminate 12 can be suppressed, thereby suppressing the temperature rise of the portion of the laminate 12 on the current collector 52 side.

[0033] In addition, in the secondary battery 100, since the corner of the housing component 30 is reinforced by the heat transfer material 20, the generation of cracks at the corner can be suppressed.

[0034] Example 2 Figure 4 This refers to the secondary battery 102 of Example 2. Additionally, in... Figure 4 In, with Figure 3Identical parts are labeled with the same reference numerals. The secondary battery 102 of Embodiment 2 differs from that of Embodiment 1 in having metal plates 60a and 60b. Additionally, the shape of the heat transfer material 20 differs from that of Embodiment 1. The secondary battery 102 of Embodiment 2 is otherwise identical to that of Embodiment 1.

[0035] In the secondary battery 102 of Example 2, the heat transfer material 20 does not cover the outer periphery 14a, 14b. Alternatively, the heat transfer material 20 of the secondary battery 102 may cover the outer periphery 14a, 14b.

[0036] Metal plates 60a and 60b are disposed inside the housing member 30. Metal plates 60a and 60b have a general plate shape extending in the x and y directions.

[0037] The metal plate 60a is in contact with the upper surface 12b of the laminate 12 (i.e., the electrode layer 14). The metal plate 60a is also in contact with the conductor film portion 34a. Furthermore, the metal plate 60a has its ends embedded in the heat transfer material 20. The ends of the metal plate 60a are surrounded by the heat transfer material 20. Additionally, the metal plate 60a only needs to be in contact with the heat transfer material 20.

[0038] The metal plate 60b is in contact with the lower surface 12c (i.e., electrode layer 14) of the laminate 12. The metal plate 60b is also in contact with the conductor film portion 34b. Furthermore, the metal plate 60b has its ends embedded in the heat transfer material 20. The ends of the metal plate 60b are surrounded by the heat transfer material 20. Additionally, the metal plate 60b only needs to be in contact with the heat transfer material 20.

[0039] During the charging and discharging of the secondary battery 102, heat is generated in the laminate 12. In the secondary battery 102, heat is readily transferred from the heat transfer material 20 to the conductor film 34a via the metal plate 60a. Additionally, in the secondary battery 102, heat is readily transferred from the heat transfer material 20 to the conductor film 34b via the metal plate 60b. Therefore, the heat generated in the laminate 12 is dissipated more efficiently.

[0040] Example 3 Figure 5 The metal plate of the secondary battery 104 in Example 3 has a different structure than that in Example 2. The other structures of the secondary battery 104 in Example 3 are the same as those in Example 2.

[0041] In the secondary battery 104, the metal plate 60a has a first portion 66a and a second portion 68a. The first portion 66a is disposed on the upper part of the sealing member 22. The first portion 66a extends in the z-direction. The lower end of the first portion 66a is in contact with the upper surface 22b of the sealing member 22. The second portion 68a is disposed on the upper part of the laminate 12 (i.e., the upper part of the electrode layer 14). The second portion 68a has a plate shape extending in both the x and y directions. The second portion 68a is connected to the upper end of the first portion 66a. The second portion 68a is bent into a convex shape toward the lower side (i.e., toward the upper surface 12b of the laminate 12). In other words, the second portion 68a is bent into a convex shape toward the electrode layer 14. The second portion 68a is bent by elastic deformation and is bonded to the upper surface 12b of the laminate 12, i.e., the electrode layer 14, by a conductive adhesive 70a. The upper surface of part 68a is bonded to the conductor film portion 34a by a conductive adhesive 70b. The conductive adhesives 70a and 70b are, for example, epoxy-based, acrylic-based, rubber-based, ethylene vinyl acetate copolymer (EVA)-based, or polyolefin-based adhesives. The softening point of the conductive adhesives 70a and 70b is preferably below 100°C.

[0042] During the charging and discharging of the secondary battery 104, heat is generated in the laminate 12. If the conductive adhesive 70a softens due to the heat generated in the laminate 12, the stress in the bent portion of the second part 68a is released, and the second part 68a deforms in a direction away from the laminate 12. As a result, the electrical connection between the second part 68a and the laminate 12 is released. Therefore, the current in the laminate 12 can be stopped. This prevents excessive temperature rise of the laminate 12. In addition, if the conductive adhesive 70c softens due to heat, the second part 68b of the metal plate 60b deforms in a direction away from the laminate 12 (i.e., the electrode layer 14), and the electrical connection between the second part 68b and the laminate 12 is released.

[0043] The upper surface 12b and lower surface 12c of the laminate 12 are examples of "end faces of the laminate". The upper surface 22b and lower surface 22c of the sealing member 22 are examples of "end faces of the sealing member".

[0044] The embodiments have been described in detail above, but these are merely illustrative and do not limit the scope of this utility model. The technology described in the technical solution includes various modifications and alterations to the specific examples exemplified above. The technical elements described in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the technical solution at the time of application. Furthermore, the technology illustrated in this specification or drawings is technology that simultaneously achieves multiple objectives; achieving one of these objectives is itself technically useful.

Claims

1. A secondary battery, characterized in that, have: A stacked structure, which is composed of multiple stacked battery cells; A housing component, which is composed of a membrane, houses the laminate; and A heat transfer material, disposed inside the housing component, is held between the sides of the laminate and the housing component. Within the length of the heat transfer material along the stacking direction of the laminate, the thermal resistance of the heat transfer material is lower than that of the housing component.

2. The secondary battery according to claim 1, characterized in that, It also has a sealing member disposed inside the receiving member and covering the side surface of the laminate; The heat transfer material covers the sides of the sealing component and the outer periphery of the electrode layer that forms the end face of the laminate.

3. The secondary battery according to claim 1, characterized in that, It also has a sealing component and a metal plate, the sealing component being disposed inside the receiving component and covering the side surface of the laminate, and the metal plate being disposed inside the receiving component and in contact with the electrode layer constituting the end face of the laminate and the end face of the sealing component; The heat transfer material covers the sides of the sealing component; The metal plate is in contact with the heat transfer material; The housing component has a conductive film portion and an insulating film portion. The conductive film portion is disposed in the portion that overlaps with the electrode layer when viewed along the stacking direction and is in contact with the metal plate. The insulating film portion covers the side of the heat transfer material and is connected to the conductive film portion.

4. The secondary battery according to claim 3, characterized in that, The metal plate has a first part and a second part, the first part being in contact with the end face of the sealing member, and the second part being bent into a convex shape towards the end face of the electrode layer and in contact with the first part at a position away from the heat transfer material; The secondary battery also includes a conductive adhesive for bonding the second portion to the end face of the electrode layer.

5. The secondary battery according to any one of claims 1 to 4, characterized in that, In the stacking direction, the thermal conductivity of the heat transfer material is higher than that of the stack.

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