Battery module

Abstract

The adhesive layer of the battery module achieves both excellent electrical and thermal conductivity. [Solution] The battery module comprises a laminate in which a plurality of electrode sheets, including a bipolar electrode sheet, are stacked; a sealant provided along the periphery of the laminate to seal the electrolyte inside the laminate; and a current collector plate joined to one end face of the laminate in the stacking direction via an adhesive layer. One end face of the laminate has a bipolar opposing region that faces both the positive electrode and the negative electrode active material layer, and a bipolar non-opposing region located outside the bipolar opposing region and not facing at least one of the positive electrode and the negative electrode active material layer. The adhesive layer has a first region composed of a first type of adhesive, at least a portion of which is located on the bipolar opposing region, and a second region composed of a second type of adhesive, at least a portion of which is located on the bipolar non-opposing region. The first type of adhesive has a lower volume resistivity than the second type of adhesive, and the second type of adhesive has a higher thermal conductivity than the first type of adhesive.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a battery module.

Background Art

[0002] Patent Document 1 describes a bipolar battery module. In the bipolar battery module, a bipolar electrode sheet is adopted in a laminate composed of a plurality of secondary battery cells. The bipolar electrode sheet has a current collector foil, a positive electrode active material layer provided on one surface of the current collector foil, and a negative electrode active material layer provided on the other surface of the current collector foil.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When bonding a current collector plate to each end face of the laminate, the adhesive layer formed between the laminate and the current collector plate is required to have excellent conductivity. In addition, from the perspective of suppressing the temperature rise of the laminate, excellent thermal conductivity is also required for the same adhesive layer. In order to realize such an adhesive layer, an adhesive excellent in both conductivity and thermal conductivity is required. However, it is difficult to require both conductivity and thermal conductivity for a single adhesive. This specification provides a technology capable of achieving both excellent conductivity and excellent thermal conductivity in the adhesive layer between the laminate of the battery module and the current collector plate.

Means for Solving the Problems

[0005] The technology disclosed herein is embodied in a battery module. In a first embodiment, the battery module may comprise a laminate comprising a plurality of electrode sheets, including a bipolar electrode sheet, laminated with a separator between them to form a plurality of secondary battery cells; a sealant provided along the periphery of the laminate to seal an electrolyte within the laminate; and a current collector plate bonded to one end face of the laminate in the lamination direction via an adhesive layer. The bipolar electrode sheet may have a current collector foil, a positive electrode active material layer provided on one side of the current collector foil, and a negative electrode active material layer provided on the other side of the current collector foil. The one end face of the laminate may have, when viewed along the lamination direction, a bipolar opposing region facing both the positive electrode active material layer and the negative electrode active material layer, and a bipolar non-opposing region located outside the bipolar opposing region and not facing at least one of the positive electrode active material layer and the negative electrode active material layer. The adhesive layer may consist of a first type of adhesive and have a first region where at least a portion is located on the anti-pole region, and a second region where at least a portion is located on the non-anti-pole region. The volume resistivity of the first type of adhesive may be lower than that of the second type of adhesive, and the thermal conductivity of the second type of adhesive may be higher than that of the first type of adhesive.

[0006] In the battery module described above, an adhesive layer is provided between one end face of the laminate and the current collector. This end face of the laminate has a bipolar opposing region that faces both the positive electrode active material layer and the negative electrode active material layer, and a bipolar non-opposing region located outside the bipolar opposing region and not facing at least one of the positive electrode active material layer and the negative electrode active material layer. The adhesive layer is composed of different types of adhesive in a first region located on the bipolar opposing region and a second region located on the bipolar non-opposing region. The volume resistivity of the adhesive in the first region is lower than that of the adhesive in the second region, and the thermal conductivity of the adhesive in the second region is higher than that of the adhesive in the first region. With this configuration, in the region of the adhesive layer where current mainly flows during charging and discharging (i.e., the first region), the electrical resistance between the laminate and the current collector is reduced. In other words, the charging and discharging characteristics of the battery module are improved. On the other hand, in the other regions (i.e., the second region), the use of an adhesive with high thermal conductivity (i.e., the second type of adhesive) enhances the thermal conductivity between the laminate and the current collector plate. This allows the heat generated within the battery module to be widely diffused to the current collector plate via the adhesive layer. In other words, the heat dissipation characteristics of the battery module are improved.

[0007] In a second aspect of this technology, in addition to the first aspect described above, the non-opposing regions of the two electrodes on one end face of the laminate may face the negative electrode active material layer but may not face the positive electrode active material layer. With this configuration, electrodeposition on the negative electrode active material layer during charging can be suppressed.

[0008] In a third aspect of this technology, in addition to the first or second aspect described above, the second region of the adhesive layer may exist only on the non-opposing regions of the two electrodes, or it may not exist on the opposing regions of the two electrodes. With this configuration, the region of the adhesive layer through which current mainly flows during charging and discharging is composed solely of a first type adhesive with excellent conductivity. This effectively improves the charging and discharging characteristics of the battery module.

[0009] In a fourth aspect of this technology, in addition to the first or second aspect described above, the second region of the adhesive layer may extend beyond the boundary between the non-opposing region and the opposing region and onto the opposing region. With this configuration, although the charge-discharge characteristics of the battery module are sacrificed, the heat dissipation characteristics of the battery module can be further improved.

[0010] In a fifth aspect of this technology, in addition to any one of the first to third aspects described above, the second region of the adhesive layer may extend from the first region of the adhesive layer to the sealant. With this configuration, the second region, which has excellent thermal conductivity, becomes relatively large, thereby further improving the heat dissipation characteristics of the battery module. [Brief explanation of the drawing]

[0011] [Figure 1] A cross-sectional view showing a battery module of the first embodiment. [Figure 2] A cross-sectional view showing a battery module of the second embodiment. [Figure 3] A table showing the results of charge / discharge tests and foreign object short-circuit tests for battery modules. [Modes for carrying out the invention]

[0012] (First Embodiment) The battery module 10 of this embodiment will be described with reference to Figure 1. The battery module 10 constitutes part of a battery pack mounted on a vehicle that drives wheels with a motor, for example. The battery pack supplies power to the vehicle's motor. Examples of vehicles on which the battery pack is mounted include battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like.

[0013] As shown in Figure 1, the battery module 10 comprises a laminate 24, a sealing body 26, and a pair of current collector plates 28.

[0014] The laminate 24 has a plurality of electrode sheets 20, 21, 22 and a plurality of separators 18. The plurality of electrode sheets 20, 21, 22 and the plurality of separators 18 are arranged alternately. That is, the plurality of electrode sheets 20, 21, 22 are laminated via the separators 18. Each separator 18 is made of an electrically insulating material and allows ion permeability. For example, a single layer or multi-layer polyethylene can be used as the material constituting the separator 18. The laminate 24 is composed of a plurality of secondary battery cells C1, C2, C3 made up of a plurality of electrode sheets 20, 21, 22 and a plurality of separators 18. Each of the plurality of secondary battery cells C1, C2, C3 is, for example, a lithium-ion battery cell.

[0015] In the laminate 24, an electrolyte 17 is placed between two adjacent electrode sheets among the multiple electrode sheets 20, 21, and 22. The electrolyte 17 is, for example, liquid. The electrolyte 17 fills the entire laminate 24, not just the area shown in Figure 1. However, the electrolyte 17 is not limited to liquid form and may be solid.

[0016] The sealant 26 is positioned along the periphery of the laminate 24. The sealant 26 is made of an electrically insulating material. For example, a resin such as polyethylene is used as the material constituting the sealant 26. The sealant 26 seals the electrolyte 17 within the laminate 24.

[0017] One of the pair of current collector plates 28 is joined to one end face of the laminate 24 in the stacking direction (i.e., the upper end face 25 in Figure 1) via an adhesive layer 30. The other of the pair of current collector plates 28 is joined to the other end face of the laminate 24 in the stacking direction (the lower end face in Figure 1) via an adhesive layer 30. The current collector plates 28 are made of a conductive material such as aluminum.

[0018] Next, the details of the plurality of electrode sheets 20, 21, 22 will be described. The plurality of electrode sheets 20, 21, 22 have a rectangular sheet shape. The plurality of electrode sheets 20, 21, 22 include a plurality of bipolar electrode sheets 20 and a pair of terminal electrode sheets 21, 22. The pair of terminal electrode sheets 21, 22 are respectively arranged at both ends in the stacking direction of the stacked plurality of bipolar electrode sheets 20 (that is, the vertical direction of the paper surface in FIG. 1).

[0019] Each of the plurality of bipolar electrode sheets 20 has a current collector foil 12, a positive electrode active material layer 13, and a negative electrode active material layer 14. The current collector foil 12 is a foil-shaped member. The current collector foil 12 has a positive electrode current collector foil (not shown) and a negative electrode current collector foil (not shown). The current collector foil 12 is formed integrally by overlapping the positive electrode current collector foil and the negative electrode current collector foil. The positive electrode current collector foil is made of, for example, copper. The negative electrode current collector foil is made of, for example, aluminum. However, the combination of the positive electrode current collector foil and the negative electrode current collector foil is not limited to this, and may be configured using other combinations of metals. In a modified example, the current collector foil 12 may be configured such that the positive electrode current collector foil and the negative electrode current collector foil are made of the same type of metal.

[0020] The positive electrode active material layer 13 is disposed on one side surface of the current collector foil 12 (the upper surface on the paper surface of FIG. 1, hereinafter also referred to as the "upper side"). The positive electrode active material layer 13 contains a positive electrode active material. Although it is an example, the positive electrode active material is made of, for example, a metal oxide containing lithium ions such as lithium iron phosphate (LiFePO4: LFP). The positive electrode active material layer 13 may contain a conductive assistant, an electrolyte, a binder, etc. in addition to the positive electrode active material.

[0021] The negative electrode active material layer 14 is disposed on the other side surface of the current collector foil 12 (the lower surface on the paper surface of FIG. 1, hereinafter also referred to as the "lower side"). Although it is an example, the negative electrode active material layer 14 is made of, for example, a carbon material such as graphite. The negative electrode active material layer 14 may contain a conductive assistant, an electrolyte, a binder, etc. in addition to the negative electrode active material.

[0022] The pair of terminal electrode sheets 21 and 22 includes a positive electrode terminal electrode sheet 21 and a negative electrode terminal electrode sheet 22. The positive electrode terminal electrode sheet 21 has a positive electrode current collector foil 15 and a positive electrode active material layer 13. The positive electrode current collector foil 15 and the positive electrode active material layer 13 are respectively configured in the same manner as the positive electrode current collector foil and the positive electrode active material layer 13 of the bipolar electrode sheet 20. The negative electrode terminal electrode sheet 22 has a negative electrode current collector foil 16 and a negative electrode active material layer 14. The negative electrode current collector foil 16 and the negative electrode active material layer 14 are respectively configured in the same manner as the negative electrode current collector foil and the negative electrode active material layer 14 of the bipolar electrode sheet 20.

[0023] Here, the upper end surface 25 of the laminate 24 is divided into two regions 25a and 25b according to the positional relationship between the above-mentioned positive electrode active material layer 13 and the negative electrode active material layer 14. When the upper end surface 25 of the laminate 24 is viewed along the stacking direction, it has a bipolar facing region 25a and a bipolar non-facing region 25b. The bipolar facing region 25a faces both the positive electrode active material layer 13 and the negative electrode active material layer 14. The bipolar non-facing region 25b is located outside the bipolar facing region 25a. Also, the bipolar non-facing region 25b faces the negative electrode active material layer 14 and does not face the positive electrode active material layer 13. In other words, the cross-sectional area of the negative electrode active material layer 14 is larger than the cross-sectional area of the positive electrode active material layer 13. The cross-sectional area here refers to the cross-sectional area when cut by a plane perpendicular to the stacking direction. According to such a configuration, it is possible to suppress the occurrence of electrodeposition on the negative electrode active material layer 14 during charging.

[0024] However, the bipolar non-facing region 25b is not limited to the above-mentioned configuration. For example, the bipolar non-facing region 25b may not face either the positive electrode active material layer 13 or the negative electrode active material layer 14. In another modification, the bipolar non-facing region 25b may face the positive electrode active material layer 13 and may not face the negative electrode active material layer 14.

[0025] Next, the details of the adhesive layer 30 will be described. The adhesive layer 30 joins the laminate 24 and the current collector plate 28. The thickness of the adhesive layer 30 may be approximately 0.3 mm or more and approximately 3 mm or less. The adhesive layer 30 is composed of different types of adhesives. The adhesive layer 30 has a first region 30a composed of a first type of adhesive and a second region 30b composed of a second type of adhesive. The first region 30a is located on the pole-opposing region 25a of the upper end surface 25, and the second region 30b is located on the pole-non-opposing region 25b of the upper end surface 25. The first type of adhesive has higher conductivity than the second type of adhesive. Specifically, the volume resistivity of the first type of adhesive is lower than that of the second type of adhesive. For example, the volume resistivity of the first type of adhesive is approximately 2.0 × 10^-6 Ω·m or less. On the other hand, the thermal conductivity of the second type of adhesive is higher than that of the first type of adhesive. For example, the thermal conductivity of the second type of adhesive is approximately 2.1 W / (m / K) or higher.

[0026] The second region 30b of the adhesive layer 30 extends from the first region 30a of the adhesive layer 30 to the sealant 26. However, in modified examples, the second region 30b of the adhesive layer 30 does not have to extend to the sealant 26. For example, the second region 30b of the adhesive layer 30 may be spaced apart from the sealant 26. The second region 30b of the adhesive layer 30 may also be spaced apart from the first region 30a of the adhesive layer 30.

[0027] In this embodiment of the battery module, an adhesive layer 30 is provided between the upper end surface 25 of the laminate 24 and the current collector plate 28. The upper end surface 25 of the laminate 24 has a bipolar opposing region 25a that faces both the positive electrode active material layer 13 and the negative electrode active material layer 14, and a bipolar non-opposing region 25b that is located outside the bipolar opposing region 25a and does not face at least one of the positive electrode active material layer 13 and the negative electrode active material layer 14. The adhesive layer 30 is composed of different types of adhesive in a first region 30a located on the bipolar opposing region 25a and a second region 30b located on the bipolar non-opposing region 25b. The volume resistivity of the adhesive in the first region 30a is lower than that of the adhesive in the second region 30b, and the thermal conductivity of the adhesive in the second region 30b is higher than that of the adhesive in the first region 30a. With this configuration, in the adhesive layer 30, the electrical resistance between the laminate 24 and the current collector plate 28 is reduced in the region where current mainly flows during charging and discharging (i.e., the first region 30a). In other words, the charging and discharging characteristics of the battery module 10 are improved. On the other hand, in the other regions (i.e., the second region 30b), the thermal conductivity between the laminate 24 and the current collector plate 28 is improved by using an adhesive with high thermal conductivity (i.e., the second type of adhesive). This allows the heat generated in the battery module 10 to be widely diffused to the current collector plate 28 via the adhesive layer 30. In other words, the heat dissipation characteristics of the battery module 10 are improved.

[0028] In particular, in this embodiment, the second region 30b of the adhesive layer 30 exists only on the non-opposing region 25b of both electrodes and not on the opposing region 25a of both electrodes. With this configuration, the region of the adhesive layer 30 through which current mainly flows during charging and discharging is composed solely of a first type adhesive with excellent conductivity. This effectively improves the charging and discharging characteristics of the battery module.

[0029] In this embodiment, the second region 30b of the adhesive layer 30 extends from the first region 30a of the adhesive layer 30 to the sealant 26. With this configuration, the second region 30b, which has excellent thermal conductivity, becomes relatively large, thereby further improving the heat dissipation characteristics of the battery module 10.

[0030] (Second Embodiment) Referring to Figure 2, only the configurations of the battery module 110 of this embodiment that differ from those of the first embodiment will be described. As shown in Figure 2, in the battery module 110, the positional relationship between the first region 130a and the second region 130b in the adhesive layer 130 is different. The other configurations of the adhesive layer 130 are the same as in the first embodiment. The second region 130b of the adhesive layer 130 may extend beyond the boundary between the non-opposing region 25b and the opposing region 25a, onto the opposing region 25a. That is, compared to the first embodiment, the area where the first region 130a, which has excellent conductivity, extends between the laminate 24 and the current collector plate 28 is smaller, while the area where the second region 130b, which has excellent thermal conductivity, extends is larger. With such a configuration, although the charge-discharge characteristics of the battery module 110 are sacrificed, the heat dissipation characteristics of the battery module 110 can be further improved.

[0031] (Examples) Examples will be described with reference to Figures 1 to 3. However, the following descriptions are not intended to limit the configurations related to this technology. As shown in Figure 3, in Examples 1-5 and Comparative Examples 1-3, battery modules similar to those of the first embodiment (Figure 1) or the second embodiment (Figure 2) were manufactured, and charge / discharge tests and foreign object short-circuit tests were performed, respectively. Note that the battery modules can be manufactured using prior art. In Examples 1 to 5 and Comparative Examples 1 to 3, except for the configuration of the adhesive layer 30, square-shaped bipolar laminated battery modules were manufactured using the materials described below. The configuration of the adhesive layer 30 will be described later. The capacity of the manufactured battery modules is 14 Ah.

[0032] (Battery module specifications) The current collector foil 12 was made of a metal foil (thickness: 50 μm) formed by laminating aluminum foil (thickness: 40 μm) and copper foil (thickness: 10 μm). The positive electrode active material layer 13 was made using LFP as the positive electrode active material (thickness: 400 μm). The negative electrode active material layer 14 was made using graphite as the negative electrode active material (thickness: 300 μm). The separator 18 was made of a single layer of polyethylene (thickness: 20 μm). The electrolyte 17 was a solution of lithium hexafluoride phosphate (LiPF6) dissolved in a mixed solvent of ethylene carbonate (EC) / dimethyl carbonate (DMC) / ethyl methyl carbonate (EMC). The current collector plate 28 was made of aluminum (thickness: 5 mm).

[0033] (Composition of the adhesive layer) In Example 1, the region located on the bipolar opposing region 25a (i.e., the first region 30a) and the region located on the bipolar non-opposing region 25b (i.e., the second region 30b) of the adhesive layer 30 (thickness: approximately 1-5 mm) were fabricated in the same manner as in the first embodiment. The adhesive constituting the first region 30a is the first conductive adhesive, which is ThreeBond's acrylic resin adhesive "3350C". The first conductive adhesive has a volume resistivity of 2.0 × 10^-6 Ω·m and a thermal conductivity of 1.4 W / (m·K). The adhesive constituting the second region 30b is the first thermal conductive adhesive, which is ThreeBond's epoxy resin adhesive "2045B". The first thermal conductive adhesive has a volume resistivity of 1.9 × 10^12 Ω·m and a thermal conductivity of 2.1 W / (m·K).

[0034] In Example 2, compared to Example 1, the adhesive constituting the second region 30b is changed to a second thermal conductive adhesive. The second thermal conductive adhesive is Widework's silicone resin adhesive "J-Thermo-03M," which has a volume resistivity of 1.0 × 10^6 Ω·m and a thermal conductivity of 3 W / (m·K). In Example 3, compared to Example 1, the adhesive constituting the first region 30a is changed to a second conductive adhesive. The second conductive adhesive is Henkel's epoxy resin adhesive "LOCTITE® ABLESTIK ICP 3920," which has a volume resistivity of 3.0 × 10^-6 Ω·m and a thermal conductivity of 1.6 W / (m·K). In Example 4, compared to Example 1, the adhesive constituting the first region 30a is the second conductive adhesive, and the adhesive constituting the second region 30b is changed to a second thermal conductive adhesive. In Example 5, compared to Example 1, the positional relationship between the first region 30a and the second region 30b of the adhesive layer 30 has been changed to the same configuration as in the second embodiment. In Figure 3, the configuration with the same position as the adhesive layer 30 of the first embodiment is labeled "1", and the configuration with the same position as the adhesive layer 130 of the second embodiment is labeled "2".

[0035] While not particularly limited, the first region 30a has a square shape, similar to the shape of the battery module fabricated in the embodiment. The second region 30b has a frame shape and surrounds the first region 30a from the outside. As an example, in Figure 1, the length L1 of position configuration 1 is approximately 400-450 mm, the length L2 is approximately 1-5 mm, and the length L3 is approximately 5-15 mm. Also, in Figure 2, the length L4 of position configuration 2 is approximately 400-450 mm, the lengths L5 and L6 are 1-5 mm, and the length L7 is approximately 400-450 mm.

[0036] Comparative Examples 1 to 3 are modified compared to Example 1 as follows: In Comparative Example 1, the adhesive constituting the region located on the non-opposing regions of the adhesive layer (corresponding to the second region 30b in Examples 1 to 5) is changed to the first conductive adhesive. In Comparative Example 2, the adhesive constituting the region located on the opposing regions of the adhesive layer (corresponding to the first region 30a in Examples 1 to 5) is changed to the first thermally conductive adhesive. In Comparative Example 3, the adhesive constituting the region located on the opposing regions of the adhesive layer and the adhesive constituting the region located on the non-opposing regions of the adhesive layer are swapped. The adhesive constituting the region located on the opposing regions of the adhesive layer is changed to the first thermally conductive adhesive, and the adhesive constituting the region located on the non-opposing regions of the adhesive layer is changed to the first conductive adhesive.

[0037] The charge / discharge test and the foreign object short-circuit test were performed as follows.

[0038] (Charge / Discharge Test) In the charge-discharge test, the battery was discharged at 13A for 10 seconds from a state of 25°C and 3.5V. The resistance value R was then measured from the voltage difference (ΔV) between before discharge and after 10 seconds of discharge, using the formula R = ΔV / 13A.

[0039] (Foreign object short circuit test) In the foreign object short-circuit test, the battery module was opened at 25°C and 2.5V, and a 100μm diameter stainless steel foreign object was placed in the gap between the non-opposing regions 25b of the upper end surface 25 of the laminate 24 (for example, the space between the separator 18 and the positive electrode current collector foil 15). Then, after charging the battery module to 3.75V, the separator 18 was destroyed and a short circuit was caused by pressing the area where the foreign object was placed. The temperature directly above the battery module at this time was measured using a thermocouple, and the temperature rise ΔT due to the short circuit was obtained.

[0040] In the charge-discharge test, comparing Comparative Examples 1-3 and Example 1, the resistance R was small, approximately 20 mΩ, in Example 1 and Comparative Example 1, where the first conductive adhesive was used in the adhesive layer 30 on the bipolar opposing region 25a. In contrast, the resistance R in Comparative Examples 2 and 3 was 1000 Ω or more and 400 mΩ, respectively. From this, it was confirmed that by using an adhesive with excellent conductivity (i.e., the first conductive adhesive) in the adhesive layer 30, especially in the bipolar opposing region 25a where current mainly flows during charging and discharging, the electrical resistance between the laminate 24 and the current collector plate 28 is reduced (i.e., the charge-discharge performance is high).

[0041] In the foreign matter short-circuit test, a comparison of Comparative Examples 1-3 and Example 1 showed that in Example 1 and Comparative Example 2, where the first thermally conductive adhesive was used in the region located on the non-opposing region 25b of the adhesive layer, the temperature rise ΔT was small, at 2-3°C. In contrast, in Comparative Examples 1 and 3, the temperature rise ΔT was high, at Δ10°C and Δ8°C, respectively. From this, it was confirmed that by using an adhesive with excellent thermal conductivity in the adhesive layer 30, particularly in the region located on the non-opposing region 25b of the adhesive layer (i.e., the second region 30b), the heat generated during a short circuit can be widely diffused to the current collector plate 28 via the adhesive layer 30 (i.e., high heat dissipation characteristics).

[0042] On the other hand, when comparing Examples 1 to 4, there was almost no difference in the results in either the charge / discharge test or the foreign object short-circuit test. This confirms that if an adhesive with excellent conductivity is used in the region located on the anti-electrode region 25a of the adhesive layer 30 (i.e., the first region 30a), and an adhesive with excellent thermal conductivity is used in the region on the non-anti-electrode region 25b of the adhesive layer 30 (i.e., the second region 30b), the charge / discharge characteristics and heat dissipation characteristics of the battery module can be maintained at a high level, even if the type and combination of adhesives differ.

[0043] Furthermore, when comparing Example 1 (Position Configuration 1 (Figure 1)) and Example 5 (Position Configuration 2 (Figure 2)), there was virtually no difference in the results in either the charge / discharge test or the foreign object short-circuit test. From this, it was confirmed that even if the second region 130b extends beyond the boundary between the non-opposing region 25b and the opposing region 25a, and the opposing region 25a is extended, as long as the first region 130a is reduced to about 5% or less, the heat dissipation characteristics of the battery module can be maintained at a high level without sacrificing its charge / discharge characteristics.

[0044] In the first and second embodiments described herein, the adhesive layer 30 has a first region 30a and a second region 30b, but is not limited thereto and may also have a third region. The third region may be located between the first region 30a and the second region 30b, or between the second region 30b and the sealant 26. [Explanation of Symbols]

[0045] 10, 110: Battery module, 12: Current collector foil, 13: Positive electrode active material layer, 14: Negative electrode active material layer, 17: Electrolyte, 18: Separator, 20: Bipolar electrode sheet, 21, 22: Terminal electrode sheet, 24: Laminate, 25: Upper surface, 25a: Opposing regions of both electrodes, 25b: Non-opposing regions of both electrodes, 26: Encapsulation body, 28: Current collector plate, 30, 130: Adhesive layer, 30a, 130a: First region, 30b, 130b: Second region, C1, C2, C3: Secondary battery cell

Claims

1. A laminate comprising multiple electrode sheets, including a bipolar electrode sheet, stacked via a separator, forming multiple secondary battery cells, A sealing body provided along the periphery of the laminate, which seals the electrolyte inside the laminate, A current collector plate is bonded to one end face of the laminated body in the stacking direction via an adhesive layer, Equipped with, The bipolar electrode sheet comprises a current collector foil, a positive electrode active material layer provided on one side of the current collector foil, and a negative electrode active material layer provided on the other side of the current collector foil. The one end face of the laminate has, when viewed along the lamination direction, a bipolar opposing region that faces both the positive electrode active material layer and the negative electrode active material layer, and a bipolar non-opposing region located outside the bipolar opposing region and not facing at least one of the positive electrode active material layer and the negative electrode active material layer. The adhesive layer is composed of a first type of adhesive and has a first region in which at least a portion is located on the opposing regions of both poles, and a second region in which at least a portion is located on the non-opposing regions of both poles. The volume resistivity of the first type of adhesive is lower than the volume resistivity of the second type of adhesive. The thermal conductivity of the second type of adhesive is higher than that of the first type of adhesive. Battery module.

2. The battery module according to claim 1, wherein the non-opposing regions of both electrodes on one end face of the laminate face the negative electrode active material layer but do not face the positive electrode active material layer.

3. The battery module according to claim 1 or 2, wherein the second region of the adhesive layer is present only on the non-opposing regions of the two electrodes and not on the opposing regions of the two electrodes.

4. The battery module according to claim 1 or 2, wherein the second region of the adhesive layer extends beyond the boundary between the non-opposing region and the opposing region and onto the opposing region.

5. The battery module according to claim 1 or 2, wherein the second region of the adhesive layer extends from the first region of the adhesive layer to the sealant.

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