Battery pack and method for manufacturing battery pack

Abstract

To provide a battery pack which is excellent in handling property at low cost, and improves easiness in disassembly of a battery module and a fixed member, and a method for manufacturing a battery pack.SOLUTION: A battery pack includes a battery module 10 having a plurality of battery cells 12, and a fixed member 20 to which the battery module 10 is fixed, wherein the battery module 10 has a first surface 13 facing the fixed member 20, the fixed member 20 has a second surface 22 facing the first surface 13 of the battery module 10, a heat conduction member 40 is provided between the first surface 13 and the second surface 22, and a release layer 30 formed of a material different from a resin constituting the heat conduction member 40 is provided on the first surface 13 so as to contact the heat conduction member 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery pack and a method for manufacturing the battery pack. [Background technology]

[0002] In recent years, secondary batteries such as lithium-ion batteries have become indispensable as rechargeable energy sources for mobile information terminals (personal computers, mobile phones, smartphones, etc.), electric vehicles (EVs), hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), etc. Batteries that require large capacity and high output are usually manufactured as battery packs, in which multiple battery cells (single cells) are stacked and bundled in a specified arrangement.

[0003] When an abnormality occurs in a battery module of a battery pack or when the battery module is to be inspected, the battery module is removed from the fixing member that is the mounting member for the battery module before the inspection. Therefore, it is preferable that the battery module in the battery pack can be easily removed from the fixing member.

[0004] The battery pack of Patent Document 1 has a sheet-like intermediate material with thermal conductivity and insulation between the battery module and the fixed member to dissipate heat from the battery module to the fixed member. The adhesive strength of the intermediate material to the battery module on a first surface that contacts the battery module is different from the adhesive strength of the intermediate material to the fixed member on a second surface opposite the first surface. Therefore, the battery pack of Patent Document 1 is designed so that the battery module can be easily removed from the fixed member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6610008 Summary of the Invention [Problem to be solved by the invention]

[0006] In the manufacturing process of the battery pack of Patent Document 1, a thermally conductive material and a film with high releasability are combined and placed between the battery module and the fixed member as an interposer. The interposer needs to be placed in an appropriate position between the battery module and the fixed member. Therefore, the battery pack of Patent Document 1 requires adjustment of the attachment position of the interposer relative to the battery module, making it difficult to handle. In addition, the number of parts in the battery pack increases, resulting in a problem of higher manufacturing costs.

[0007] At least one embodiment of the present invention has been made in consideration of the above-mentioned circumstances, and specifically, an object of the present invention is to provide a battery pack and a method for manufacturing the battery pack that are low-cost, have excellent handling properties, and improve the ease of disassembling the battery module and the fixed member. [Means for solving the problem]

[0008] In order to solve the above problem, the battery pack of the present invention is a battery pack comprising a battery module having a plurality of battery cells and a fixing member to which the battery module is fixed, wherein the battery module has a first surface facing the fixing member, the fixing member has a second surface facing the first surface of the battery module, a heat conductive member is provided between the first surface and the second surface, and a release layer formed of a material different from the resin constituting the heat conductive member is provided on the first surface so as to be in contact with the heat conductive member.

[0009] In addition, the manufacturing method of a battery pack of the present invention is a manufacturing method of a battery pack including a battery module having a plurality of battery cells and a fixed member to which the battery module is fixed, and includes a heat conduction member forming step of providing a heat conduction member between a first surface of the battery module facing the fixed member and a second surface of the fixed member facing the battery module, and a release layer forming step of providing a release layer formed of a material different from the resin constituting the heat conduction member on the first surface so as to be in contact with the heat conduction member. [Effects of the Invention]

[0010] According to at least one embodiment of the present invention, it is possible to provide a battery pack and a method for manufacturing the battery pack that are low cost, have excellent handleability, and are easy to disassemble the battery module and the fixed member. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic exploded perspective view of the battery pack according to the embodiment. [Figure 2] 1 is a schematic cross-sectional view of a battery pack according to an embodiment of the present invention. [Figure 3] 3 is a flowchart showing steps in a method for manufacturing a battery pack according to the present embodiment. [Figure 4] 10 is a flowchart showing each processing step included in a release layer forming step. [Figure 5] FIG. 1 is a schematic diagram showing an example of a specimen prepared in an example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown here are merely examples for embodying the technical idea of ​​the present invention and are not intended to limit the present invention. Furthermore, all other embodiments, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the scope of the inventions set forth in the claims and their equivalents.

[0013] The drawings attached to this specification may be represented schematically and with scale, aspect ratio, shape, etc., appropriately changed from the actual product for the convenience of illustration and ease of understanding, but these are merely examples and do not limit the interpretation of the present invention.

[0014] In the following description, when ordinal numbers such as "first" and "second" are used, they are used for convenience and do not specify any particular order unless otherwise specified. Furthermore, the range "A to B" includes A and B and means "greater than or equal to A and less than or equal to B." Furthermore, in this specification, the thickness direction of the battery pack 1 is sometimes referred to as the Z direction, and directions parallel to the main surfaces of the battery module 10 and the fixed member 20 (such as the lower surface (bottom surface) of the battery module 10 and the upper surface (flat surface) of the fixed member 20 in FIG. 1) (directions intersecting with the Z direction) are sometimes referred to as the X direction and the Y direction.

[0015] The configuration of the battery pack 1 according to this embodiment will be described.

[0016] As shown in FIG. 1, the battery pack 1 includes a battery module 10 and a fixed member 20 to which the battery module 10 is attached.

[0017] 2, the battery module 10 is an assembled battery in which a plurality of battery cells 12, which are single cells, are arranged in parallel or stacked in a housing 11. The battery module 10 can be configured as a secondary battery such as a lithium ion battery module, but is not particularly limited thereto.

[0018] The battery module 10 has a first surface 13 that faces the fixed member 20. In FIG. 1, the first surface 13 is the hatched surface area that corresponds to the bottom surface of the battery module 10. As shown in FIG. 2, the battery cells 12 are fixed to the inner surface of the first surface 13 with a thermally conductive adhesive 14.

[0019] A release layer 30 having releasability (peelability) is formed on the outer surface of the first surface 13, which faces the fixed member 20 of the battery module 10. As shown in Fig. 2, the battery module 10 is arranged so that the release layer 30 comes into contact with a heat conductive member 40 formed on the surface (second surface 22) of the fixed member 20 facing the battery module 10.

[0020] The fixed member 20 is a member to which the battery module 10 is attached. The fixed member 20 has a surface facing the battery module 10 as a second surface 22. In FIG. 1 , the second surface 22 corresponds to the flat surface of the housing 21 of the fixed member 20. The fixed member 20 has a heat conduction member 40 provided on the second surface 22.

[0021] The fixed member 20 is capable of mounting at least the battery module 10 and has the function of dissipating heat transferred from the battery module 10 via the thermally conductive member 40. The fixed member 20 can be configured, for example, as a battery cooler or the like having a cooling function for coolant or the like.

[0022] In the battery pack 1 of this embodiment, the first surface 13 is the lower surface (bottom surface) of the battery module 10, and the second surface 22 is the upper surface (flat surface) of the fixed member 20. However, the first surface 13 and the second surface 22 are surfaces formed at positions that face each other when at least the battery module 10 and the fixed member 20 are attached. Therefore, when the battery module 10 and the fixed member 20 are installed in a direction different from the Z direction, which is the thickness direction, (for example, the X direction or Y direction), the side surface of the battery module 10 that faces the fixed member 20 becomes the first surface 13, and the side surface of the fixed member 20 that faces the battery module 10 becomes the second surface 22.

[0023] The release layer 30 is formed so as to cover at least a portion of the first surface 13 of the battery module 10. From the viewpoint of releasability of the battery module 10, the release layer 30 is formed so as to be in contact with at least the thermally conductive member 40 formed on the second surface 22 of the fixed member 20. When the release layer 30 is formed on the first surface 13 of the battery module 10 that faces the fixed member 20, the vertical peeling force required when peeling the battery module 10 from the fixed member 20 can be reduced, thereby improving the ease of disassembly of the battery pack 1.

[0024] The release layer 30 is formed of a material different from that constituting the thermally conductive material so that the battery module 10 placed on the fixed member 20 can be easily peeled off and disassembled. Specifically, the release layer 30 is composed of a resin that has releasability (non-adhesiveness) with respect to the second surface 22 of the fixed member 20 and the thermally conductive member 40. A preferred material with releasability is a fluorine-containing material such as a fluororesin. Fluororesin has excellent water- and oil-repellent properties, a large contact angle, and a low wettability due to its molecular structure. Furthermore, fluororesin has an extremely low critical surface tension (γc), a measure of wettability, and has the property of easily repelling liquids but not wetting them. Therefore, using a fluororesin as the material constituting the release layer 30 reduces adhesion to the thermally conductive member 40, thereby enabling the battery module 10 to be easily peeled off from the fixed member 20.

[0025] The material of the release layer 30 is preferably a fluororesin from the viewpoint of releasability, and suitable examples thereof include PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane polymer), FEP (perfluoroethylenepropene copolymer), and ETFE (ethylene-tetrafluoroethyleneethylene copolymer). The release layer 30 may be composed of one or more types of fluororesin. The release layer 30 may be composed of only fluororesin, or may be composed of other resins containing fluororesin. Furthermore, when silicone resin is not used for the heat conduction member 40, the material of the release layer 30 may be a silicone resin that exhibits releasability other than fluororesin.

[0026] Because the release layer 30 is disposed between the battery cell 12 and the thermally conductive member 40, its thermal resistance tends to increase as its thickness increases. When a fluororesin (PTFE) is used for the release layer 30, the thermal resistance (%) of the release layer 30 relative to the components other than the release layer 30 that are interposed between the battery cell 12 and the second surface 22 of the fixed member 20 (e.g., the thermally conductive adhesive 14, housing 11, thermally conductive member 40, and housing 21 shown in FIG. 2 ) is 0.9% at 20 μm, 2.2% at 50 μm, 3.5% at 80 μm, and 4.3% at 100 μm. To minimize the thermal resistance between the battery module 10 and the fixed member 20 while ensuring releasability, the thermal resistance of the release layer 30 is preferably set to 5% or less. Therefore, the thickness of the release layer 30 is preferably 20 μm or more and 100 μm or less.

[0027] The thermally conductive member 40 is provided on the second surface 22 of the fixed member 20 and is made of a material different from the release layer 30. The thermally conductive member 40 is made of a thermally conductive composition that has a higher thermal conductivity than air, and is made by impregnating an inorganic filler into a silicone resin, urethane resin, or the like. A heat-dissipating gap filler such as a thermally conductive silicone gap filler or a thermally conductive urethane gap filler can be suitably used as the thermally conductive member 40. The thermally conductive member 40 has fluidity when formed on the second surface 22 and hardens when left at room temperature or when heated.

[0028] The heat conducting member 40 is applied to the second surface 22 of the fixed member 20 using an application device such as a dispenser. The shape of the heat conducting member 40 is not particularly limited as long as it is a shape that at least allows the heat of the battery module 10 to be appropriately dissipated, and the heat conducting member 40 may be formed in the shape of multiple strips as shown in FIG. 1 or in other shapes such as a zigzag shape. The area where the heat conducting member 40 is formed may be a part of the second surface 22 of the fixed member 20, as shown in FIG. 1, or may be the entire surface of the second surface 22.

[0029] Next, a method for manufacturing the battery pack 1 will be described.

[0030] 3 shows steps in the manufacturing method of the battery pack 1 according to this embodiment, from forming a release layer 30 on the first surface 13 of the battery module 10 to forming a heat-conducting member 40 on the second surface 22 of the fixed member 20 to mounting the battery module 10 on the fixed member 20. The processing details of each step will be described below.

[0031] As shown in FIG. 3, the manufacturing method of the battery pack 1 includes at least a release layer forming process S1 in which a release layer 30 is provided on the first surface 13 of the battery module 10, a heat conduction member forming process S2 in which a heat conduction member 40 is provided on the second surface 22 of the fixed member 20, and an mounting process S3 in which the battery module 10 is mounted on the fixed member 20.

[0032] 3 do not necessarily have to be performed in this order, and the order of the steps is not limited as long as the battery pack 1 described above can be manufactured. For example, the release layer forming step S1 and the heat conductive member forming step S2 may be performed in reverse order, or may be performed simultaneously. Furthermore, the method for manufacturing the battery pack 1 may include steps other than those shown in FIG. 3 without departing from the scope of the present invention.

[0033] <Release layer forming process> The release layer forming process S1 is a process of providing a release layer 30 on the first surface 13 of the battery module 10. As shown in FIG. 4, the release layer forming process S1 can include a degreasing process S11, a polishing process S12, a first coating process S13, a second coating process S14, a firing process S15, and an inspection process S16.

[0034] The degreasing step S11 is a step of degreasing the surface that will become the first surface 13 of the battery module 10. The degreasing treatment performed in the degreasing step S11 includes thermal degreasing. The thermal degreasing is performed, for example, at a predetermined temperature (a high temperature of 400°C or higher) for a predetermined time using an electric baking furnace or the like. The degreasing step S11 is not limited to thermal degreasing, and any method that can degrease the first surface 13 may be used. The degreasing step S11 can completely remove dirt and deposits from the first surface 13 of the battery module 10, thereby improving the adhesion between the first surface 13 and the release layer 30.

[0035] The polishing step S12 is a step of smoothing the surface by performing a predetermined polishing process on the first surface 13 of the degreased battery module 10. Examples of the polishing process performed in the polishing step S12 include sandblasting. Sandblasting involves polishing the first surface 13 using a known sandblasting device. The polishing step S12 is not limited to sandblasting, and any method can be used as long as it can polish the first surface 13 and smooth it to a predetermined surface roughness (e.g., Ra 0.8 μm). The polishing step S12 can remove an oxide film formed on the first surface 13, thereby further improving the adhesion between the first surface 13 and the release layer 30.

[0036] The first coating step S13 is a step of applying a primer to the first surface 13 of the battery module 10 to form a primer layer. The material of the primer used can be appropriately selected from materials suitable for the release layer 30 applied in the second coating step S14. The coating process in the first coating step S13 is not particularly limited as long as it is a method that can form a primer layer on the first surface 13 of the battery module 10. The first coating step S13 may also include a step of drying the formed primer layer using an electric baking furnace or the like.

[0037] The second coating step S14 is a step of applying a material that will become the release layer 30 to the primer layer to form the release layer 30. The coating process in the second coating step S14 is not particularly limited as long as it is a method that can form the release layer 30 on the first surface 13 of the battery module 10.

[0038] The baking step S15 is a step of baking the release layer 30 applied in the second coating step S14. In the baking step S15, a baking treatment is performed using an electric baking furnace or the like at a baking temperature and for a baking time that allows the release layer 30 to be formed.

[0039] The inspection step S16 is a step of inspecting the release layer 30 after the firing step S15. The inspection step S16 can be performed by visual inspection by an operator or the like.

[0040] <Thermal Conductive Layer Forming Process> The heat conducting member forming step S2 is a step of providing the heat conducting member 40 on the second surface 22 of the fixed member 20. In the heat conducting member forming step S2, the heat conducting member 40 can be provided at a predetermined location on the second surface 22 of the fixed member 20 using an application device such as a dispenser.

[0041] Mounting process The mounting step S3 is a step of mounting the battery module 10 having the release layer 30 on the first surface 13 to the fixed member 20 having the thermally conductive member 40 on the second surface 22. In the mounting step S3, the battery module 10 is placed on the fixed member 20 with the release layer 30 in contact with the thermally conductive member 40.

[0042] As described above, the battery pack 1 according to this embodiment comprises a battery module 10 having a plurality of battery cells 12 and a fixed member 20 to which the battery module 10 is fixed, the battery module 10 having a first surface 13 facing the fixed member 20, the fixed member 20 having a second surface 22 facing the first surface 13 of the battery module 10, a heat conductive member 40 being provided between the first surface 13 and the second surface 22, and a release layer 30 formed of a material different from the resin constituting the heat conductive member 40 being provided on the first surface 13 so as to be in contact with the heat conductive member 40.

[0043] With this configuration, the release layer 30 formed on the first surface 13 of the battery module 10 reduces adhesion between the battery pack 1 and the heat conductive member 40 formed on the second surface 22 of the fixed member 20. Therefore, the vertical peeling force required to peel the battery module 10 from the fixed member 20 is reduced, improving ease of disassembly.

[0044] In the battery pack 1, the release layer 30 may be made of a material containing fluorine.

[0045] With this configuration, the release layer 30 has excellent water and oil repellency, and by using a material containing fluorine with an extremely small critical surface tension (γc), it is possible to reduce adhesion to the heat conductive member 40. Therefore, the vertical peeling force required to peel the battery module 10 from the fixed member 20 is reduced, improving ease of disassembly of the battery pack 1.

[0046] In the battery pack 1, the thickness of the release layer 30 may be 20 μm or more and 100 μm or less.

[0047] With this configuration, the thermal resistance of the release layer 30 tends to increase as the thickness increases, so if the thickness is set within the above range, the thermal resistance between the battery module 10 and the fixed member 20 can be minimized while ensuring releasability.

[0048] In addition, in the battery pack 1, the release layer 30 may be made to contain a fluororesin, or may be made to contain any of PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane polymer), FEP (perfluoroethylenepropene copolymer), and ETFE (ethylene-tetrafluoroethylene copolymer).

[0049] With this configuration, the release layer 30 can adhere closely to the heat conduction member 40 formed on the second surface 22 of the fixed member 20 by using the aforementioned fluororesin, thereby improving the ease of disassembly of the battery pack 1.

[0050] The manufacturing method of the battery pack 1 according to this embodiment is a manufacturing method of a battery pack 1 including a battery module 10 having a plurality of battery cells 12 and a fixed member 20 to which the battery module 10 is fixed, and includes a heat conduction member forming process S2 in which a heat conduction member 40 is provided between a first surface 13 of the battery module 10 facing the fixed member 20 and a second surface 22 of the fixed member 20 facing the battery module 10, and a release layer forming process S1 in which a release layer 30 formed of a material different from the resin constituting the heat conduction member 40 is provided on the first surface 13 so as to be in contact with the heat conduction member 40.

[0051] With this configuration, the release layer 30 is formed on the first surface 13 of the battery module 10, which reduces adhesion to the heat conductive member 40 formed on the second surface 22 of the fixed member 20. Therefore, the above manufacturing method can manufacture a battery pack 1 that is easy to disassemble.

[0052] In the method for manufacturing the battery pack 1, the release layer 30 may be made of a material containing fluorine.

[0053] With this configuration, by using a material containing fluorine as the release layer 30 that has excellent water and oil repellency and an extremely small critical surface tension (γc), it is possible to manufacture a battery pack 1 that has low adhesion to the heat conduction member 40 and is easy to disassemble. can.

[0054] In addition, in the manufacturing method of the battery pack 1, the release layer forming process S1 includes a degreasing process S11 in which the first surface 13 of the battery module 10 is heated and degreased, and a polishing process S12 in which the heated and degreased first surface 13 is polished, and the release layer 30 may be arranged after the first surface 13 has been polished.

[0055] The degreasing process completely removes dirt and deposits from the first surface 13 of the battery module 10, thereby improving the adhesion between the first surface 13 and the release layer 30. Furthermore, if an oxide film is formed on the first surface 13, the adhesion between the base material of the housing 11 and the release layer 30 is weak, and there is a risk that the first surface 13 will peel off along with the oxide film. However, by subjecting the first surface 13 to a polishing process after thermal degreasing, the oxide film formed on the first surface 13 can be removed, thereby further improving the adhesion between the first surface 13 and the release layer 30.

[0056] The following embodiments are also within the scope of the present invention: a battery pack according to claim 1 having the features of claim 2; a battery pack according to claim 1 or 2 having the features of claim 3; a battery pack according to any one of claims 1 to 3 having the features of claim 4; a method for manufacturing a battery pack having the features of claim 5; a method for manufacturing a battery pack according to claim 5 having the features of claim 6; and a method for manufacturing a battery pack according to claim 5 or 6 having the features of claim 7. [Example]

[0057] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to the following examples.

[0058] Examples and comparative examples of the battery pack according to the embodiment of the present invention will be described.

[0059] [Sample specifications] The samples of Examples 1 to 3 and Comparative Examples 1 to 6 had the following specifications.

[0060] First, specimens (first specimen, second specimen) were prepared to constitute the samples of Examples 1 to 3 and Comparative Examples 1 to 6. Of the specimens, the first specimen was assumed to be a battery module, and the second specimen was assumed to be a fixed member. The specimens of Examples 1 to 3, Comparative Examples 1 to 3, and Comparative Examples 4 to 6 all had the same specifications.

[0061] <1st specimen> Material: Aluminum alloy (A5052) Dimensions: 12.7mm x 12.7mm x 38mm (cuboid) <Second specimen> Material: Aluminum alloy (A6063) Dimensions: 12.7mm x 12.7mm x 38mm (cuboid).

[0062] Fig. 5 is a diagram showing an example of the configuration of a test specimen 100. As shown in Fig. 5, the test specimen 100 is composed of a first test specimen 101 corresponding to a battery module and a second test specimen 102 corresponding to a fixed member.

[0063] In the specimens 100 of Examples 1 to 3, a first forming layer 110 made of fluororesin (PTFE) functioning as a release layer was formed on the first surface of the first specimen 101 facing the second specimen 102. In the specimens 100 of Comparative Examples 1 to 3, nothing was formed on the first surface of the first specimen 101. In the specimens 100 of Comparative Examples 4 to 6, a layer of silicone resin exhibiting release properties was formed as the first forming layer 110 on the first surface of the first specimen 101. In addition, in the specimens 100 of Examples 1 to 3 and Comparative Examples 1 to 6, a heat dissipation gap filler (base agent: silicone resin) functioning as a heat conductive member was formed as the second forming layer 120 on the second surface of the second specimen 102 facing the first specimen 101.

[0064] [Manufacturing Procedure] Specimens serving as the samples of Examples 1 to 3 and Comparative Examples 1 to 6 were prepared according to the following procedure.

[0065] To remove oil from the first surface of the prepared first specimen, the specimen was degreased using ultrasonic cleaning for 5 minutes and then dried. Next, a sandblasting device was used to polish each surface so that the surface roughness of the first and second surfaces was Ra 0.8 μm. Next, a primer was applied to the surface that would become the first surface of the first specimen in the first painting process to form a primer layer, and then a fluororesin or silicone resin, which serves as a non-stick resin, was applied in the second painting process, followed by a baking process to form a first forming layer. Note that in Comparative Examples 1 to 3, the above steps were omitted because the first forming layer was not formed.

[0066] Next, a heat dissipation gap filler was applied to the second surface of the second specimen, and a chip (small piece) of a specified thickness was placed on it to adjust the height between the first and second specimens.The chip was then sandwiched between the first and second specimens and dried at a specified temperature to produce the specimens.

[0067] [Evaluation test] In the evaluation test, a vertical tensile test was conducted in accordance with JIS K6849:1994 to examine the dismantling property of the battery pack (peelability between the battery module and the fixed member), and the tensile strength (MPa) and the fracture surface after peeling were observed to determine the peel mode (interfacial peeling or cohesive peeling). The test was performed using an autograph manufactured by Shimadzu Corporation, with the tensile speed set at 50 mm / min. The test results are shown in Table 1.

[0068] [Table 1]

[0069] [result] As shown in Table 1, Examples 1 to 3 were specimens in which a fluororesin (PTFE) was formed as a first layer. The tensile strength ranged from 0.08 MPa to 0.12 MPa, and the peeling mode was interfacial peeling in all cases. In contrast, Comparative Examples 1 to 3 were specimens in which no first layer was formed. The tensile strength ranged from 0.25 MPa to 0.39 MPa, and the peeling mode was cohesive peeling in all cases. These results confirmed that when a layer made of a fluororesin with release properties is formed on a battery module as a release layer, it can be peeled off from the heat conductive member to be adhered with a weak tensile force by interfacial peeling. It was also confirmed that the use of a fluorine-containing material with excellent water and oil repellency and an extremely low critical surface tension (γc) as the release layer reduced adhesion to the heat conductive member, improving peelability.

[0070] In Comparative Examples 4 to 6, specimens were coated on the first surface with a silicone resin exhibiting mold releasability. The tensile strengths were in the range of 0.38 MPa to 0.41 MPa, and all exhibited cohesive peeling. Silicone resins form siloxane bonds with the silicone resin constituting the thermal conductive member through a dehydration condensation reaction between silanol groups: Si-OH + HO-Si → Si-O-Si (siloxane bond) + HO, or a condensation reaction between silanol groups and hydrolyzable groups: Si-OH + RO-Si → Si-O-Si + R-OH, or a heat-triggered crosslinking reaction. In Comparative Examples 4 to 6, because both the first and second formation layers were silicone resins, the siloxane bonds of the silicone resins described above improved the bonding strength at the interface, resulting in cohesive peeling and likely resulting in higher tensile strength. In contrast, in Examples 1 to 3, a fluororesin, a material different from the silicone resin that is the base agent of the thermal conductive member, was used as the first forming layer. Therefore, siloxane bonds were not generated by the condensation reaction or crosslinking reaction described above, as in Comparative Examples 4 to 6, and it is thought that this resulted in a reduction in tensile strength.

[0071] As described above, in a battery pack in which a battery module is placed on a fixed member on which a thermally conductive member is formed, it has been confirmed that "providing a release layer made of a material different from the thermally conductive member on the first surface of the battery module," and in particular, "forming the release layer from a material containing fluorine, such as fluororesin," is useful for improving the ease of disassembly of the battery pack. [Explanation of symbols]

[0072] 1 battery pack, 10 battery modules, 11 housings, 12 battery cells, 13 Page 1, 20 Fixed member, 21 enclosures, 22 2nd page, 30 release layer, 40 heat conducting member, 100 specimens, 101 1st specimen, 102 Second specimen, 110 First cambium, 120 The second cambium.

Claims

1. A battery pack including a battery module having a plurality of battery cells and a fixed member to which the battery module is fixed, the battery module has a first surface facing the fixed member, the fixed member has a second surface facing the first surface of the battery module, a heat conductive member is provided between the first and second surfaces; a release layer formed of a material different from the resin constituting the thermally conductive member is provided on the first surface so as to be in contact with the thermally conductive member.

2. The battery pack according to claim 1 , wherein the release layer is made of a material containing fluorine.

3. 3. The battery pack according to claim 1, wherein the release layer has a thickness of 20 [mu]m or more and 100 [mu]m or less.

4. 3. The battery pack according to claim 1, wherein the release layer contains any one of PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane polymer), FEP (perfluoroethylene propene copolymer), and ETFE (ethylene-tetrafluoroethylene copolymer).

5. A method for manufacturing a battery pack including a battery module having a plurality of battery cells and a fixed member to which the battery module is fixed, comprising: a heat conduction member forming step of providing a heat conduction member between a first surface of the battery module facing the fixed member and a second surface of the fixed member facing the battery module; a release layer forming step of providing a release layer formed of a material different from the resin constituting the heat conductive member on the first surface so as to be in contact with the heat conductive member; A method for manufacturing a battery pack, comprising:

6. The method for manufacturing a battery pack according to claim 5 , wherein the release layer is made of a material containing fluorine.

7. The release layer forming step includes: a degreasing step of heating and degreasing the first surface of the battery module; a polishing step of polishing the first surface that has been heated and degreased, The method for manufacturing a battery pack according to claim 5 or 6, wherein the release layer is disposed after the first surface is polished.

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