Thermosetting resin sheet, method for producing thermosetting resin sheet, and method for producing battery

Abstract

This thermosetting resin sheet is a sheet of a thermosetting resin and has a sheet-like core material having a coefficient of thermal expansion lower than that of the thermosetting resin.

Description

Thermosetting resin sheet, method for producing thermosetting resin sheet, and method for producing battery

[0001] The present disclosure relates to a thermosetting resin sheet, a method for producing a thermosetting resin sheet, and a method for producing a battery.

[0002] A thermosetting resin sheet that functions as an adhesive sheet for bonding two members while maintaining a constant distance therebetween is known. For example, Patent Document 1 proposes a thermosetting resin sheet that has initial adhesiveness and is excellent in bonding workability. Besides this, thermosetting resin sheets that function as a sealing sheet for sealing between two members are also known.

[0003] Japanese Patent Application Laid-Open No. 06-017012

[0004] When mounting the thermosetting resin sheet between two members, the thermosetting resin sheet is heated to melt the thermosetting resin. However, if the linear thermal expansion coefficients of the two members are low, the difference in linear thermal expansion coefficient between the thermosetting resin and the two members may cause distortion of the thermosetting resin sheet.

[0005] The present disclosure has been made in view of such a problem, and one of the exemplary objects of an aspect thereof is to provide a technique capable of suppressing distortion of a thermosetting resin sheet.

[0006] In order to solve the above problem, the thermosetting resin sheet according to an aspect of the present disclosure is a sheet of thermosetting resin and has a sheet-shaped core material having a coefficient of thermal expansion lower than that of the thermosetting resin.

[0007] Another aspect of the present disclosure is a method for producing a thermosetting resin sheet. This method is the above-described method for producing a thermosetting resin sheet, and includes sandwiching a core material between sheets of thermosetting resin.

[0008] Still another aspect of the present disclosure is also a method for producing a thermosetting resin sheet. This method is the above-described method for producing a thermosetting resin sheet, and includes impregnating a core material with a thermosetting resin.

[0009] A further aspect of the present disclosure is a method for manufacturing a battery. This method comprises preparing components including a current collector and the thermosetting resin sheet described above, and assembling the prepared components, the assembly of which includes heating the thermosetting resin sheet with the thermosetting resin sheet sandwiched between the current collectors.

[0010] According to certain aspects of this disclosure, distortion of the thermosetting resin sheet can be suppressed.

[0011] This is a cross-sectional view of a thermosetting resin sheet according to an embodiment. This is a process diagram showing the manufacturing process of the thermosetting resin sheet of Figure 1. This is a diagram illustrating an example of the formation process of Figure 2. This is a diagram showing a battery equipped with the thermosetting resin sheet of Figure 1. Figures 5(a) and 5(b) show a battery equipped with a thermosetting resin sheet according to a comparative example. This is a process diagram showing the manufacturing process of the battery of Figure 4. This is a cross-sectional view of a thermosetting resin sheet according to a modified example. This is a cross-sectional view showing one fiber among many fibers when the core material of the thermosetting resin sheet according to the modified example is a fibrous structure.

[0012] Before describing the embodiments in detail, an overview of the embodiments will be given. This embodiment relates to a thermosetting resin sheet. The thermosetting resin sheet functions as an adhesive sheet that joins two members while maintaining a constant distance between them. In this case, the thermosetting resin softens and penetrates into the fine irregularities on the surfaces of the two members, and as the thermosetting resin hardens in that state, the two members and the thermosetting resin sheet, that is, the two members are joined to each other via the thermosetting resin. The thermosetting resin sheet also functions as a sealing sheet that seals the space between the two members. In this case, the thermosetting resin sheet exhibits sufficient sealing performance because the thermosetting resin softens and penetrates into the fine irregularities on the surfaces of the two members.

[0013] In any case, when a thermosetting resin sheet is installed between two components, the thermosetting resin sheet is heated to soften it. However, if the two components are made of materials with low linear thermal expansion coefficients, such as metal, the thermosetting resin sheet may become distorted due to the difference in linear thermal expansion coefficients between the thermosetting resin and the two components. In contrast, in this embodiment, the thermosetting resin sheet has a core material with a lower linear thermal expansion coefficient than the thermosetting resin itself. As a result, the overall linear thermal expansion coefficient of the thermosetting resin sheet is reduced, and therefore the difference in linear thermal expansion coefficients between the thermosetting resin sheet and the two components is reduced, suppressing distortion of the thermosetting resin sheet.

[0014] Preferred embodiments will be described below with reference to the drawings. These embodiments are illustrative and not limiting to the disclosure, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted where appropriate.

[0015] Figure 1 is a cross-sectional view of a thermosetting resin sheet 100 according to an embodiment. Figure 1 can also be considered an example of application of the thermosetting resin sheet 100. In Figure 1, the thermosetting resin sheet 100 is installed between a first member 10 and a second member 12. The thermosetting resin sheet 100 functions as an adhesive sheet that joins the first member 10 and the second member 12 while maintaining a certain distance between them, and / or as a sealing sheet that seals the space between the first member 10 and the second member 12.

[0016] The thermosetting resin sheet 100 includes a sheet-like core material 110 and two thermosetting resin layers 120, which are layers of thermosetting resin. The core material 110 is sandwiched between the two thermosetting resin layers 120. In other words, the thermosetting resin sheet 100 is a sheet of thermosetting resin having a sheet-like core material 110.

[0017] The relative thicknesses of the core material 110 and the two thermosetting resin layers 120 are not particularly important. In other words, the core material 110 may be thicker than the thermosetting resin layers 120, or it may be thinner than the thermosetting resin layers 120. The thicknesses of the two thermosetting resin layers 120 are typically the same, but they may be different.

[0018] The thermosetting resin layer 120 has a low coefficient of linear thermal expansion, specifically 5.0 x 10⁻⁶. －４ The following linear thermal expansion coefficients may be present. In this case, even if members 10 and 12 are made of metal (e.g., aluminum, stainless steel, copper, nickel, etc.), that is, even if members 10 and 12 have low linear thermal expansion coefficients, the difference in linear thermal expansion coefficients between the thermosetting resin layer 120 and members 10 and 12 is small, thus suppressing distortion of the thermosetting resin layer 120 and, consequently, the thermosetting resin sheet 100.

[0019] The thermosetting resin layer 120 preferably has electrolyte resistance. Here, "electrolyte resistance" refers to resistance to electrolytes, meaning that it does not undergo a chemical reaction when in contact with an electrolyte and therefore does not deteriorate when in contact with an electrolyte. When the thermosetting resin layer 120 has electrolyte resistance, the thermosetting resin sheet 100 can be used in an environment where it comes into contact with an electrolyte.

[0020] The thermosetting resin layer 120 preferably has excellent electrolyte adhesion resistance. Here, "electrolyte adhesion resistance" refers to the property of maintaining adhesive strength even when in contact with an electrolyte. When the thermosetting resin layer 120 has excellent electrolyte adhesion resistance, the thermosetting resin sheet 100 can be used as an adhesive sheet in environments where it comes into contact with an electrolyte.

[0021] The thermosetting resin layer 120 is not particularly limited, but may be a mixture of a prepolymer and a curing agent. The thermosetting resin layer 120 is not particularly limited, but may be an epoxy resin, for example, an epoxy resin mixed with a curing agent.

[0022] The thermosetting resin layer 120 preferably has a low Young's modulus, more specifically, a Young's modulus of 100 MPa or less. In this case, the thermosetting resin layer 120 is less likely to peel off from the members 10 and 12.

[0023] The thermosetting resin layer 120 preferably has low hygroscopicity. When the thermosetting resin sheet 100 is heated during bonding, the water absorbed by the thermosetting resin layer 120 vaporizes when heated and escapes from the thermosetting resin layer 120, which may leave holes in the thermosetting resin layer 120. These holes may then cause damage to the thermosetting resin layer 120. Therefore, it is preferable for the thermosetting resin layer 120 to have low hygroscopicity.

[0024] The core material 110 has a lower linear thermal expansion coefficient than the thermosetting resin. As a result, the overall linear thermal expansion coefficient of the thermosetting resin sheet 100 is lower than when the thermosetting resin sheet 100 does not have a core material 110, i.e., when the thermosetting resin sheet 100 is composed only of a thermosetting resin layer 120. Therefore, even when members 10 and 12 are metal, i.e., have a low linear thermal expansion coefficient, the difference in linear thermal expansion coefficients between the thermosetting resin sheet 100 and members 10 and 12 is small, and distortion of the thermosetting resin sheet 100 is suppressed. The core material 110 may be formed from a polyester resin having a low linear thermal expansion coefficient similar to that of metal, specifically PET (polyethylene terephthalate).

[0025] When the core material 110 is made of a material with a melting point (for example, resin, metal, etc.), the melting point of the core material 110 is preferably higher than the thermosetting temperature of the thermosetting resin. As a result, when the thermosetting resin sheet 100 is attached, if the thermosetting resin sheet 100 is heated to a temperature above the thermosetting temperature of the thermosetting resin but below the melting point of the core material 110, the core material 110 will not melt, and thus the shape of the core material 110 can be maintained. The thermosetting resin layer 120's spreading in the planar direction when it softens is suppressed by the presence of the core material 110, whose shape is maintained.

[0026] When the core material 110 is made of a material that does not have a melting point (for example, wood or paper), the heat resistance temperature of the core material 110 is preferably higher than the thermosetting temperature of the thermosetting resin. The heat resistance temperature may also be the temperature at which the core material 110 can maintain its shape. This allows the shape of the core material 110 to be maintained when the thermosetting resin sheet 100 is heated to a temperature above the thermosetting temperature of the thermosetting resin but below the heat resistance temperature of the core material 110 during installation. The thermosetting resin layer 120's spread in the planar direction when it softens is suppressed by the presence of the core material 110, whose shape is maintained.

[0027] The core material 110 preferably has a structure that can be impregnated with a thermosetting resin, and more specifically, has pores or minute irregularities on at least its surface. In this case, the contact area between the core material 110 and the thermosetting resin layer 120 increases, thereby improving the bonding strength between the core material and the thermosetting resin. The core material 110 may be a fibrous structure composed of fibers, as a structure that can be impregnated with a thermosetting resin. For example, the core material 110 may be a nonwoven, woven, or knitted fibrous structure. In this case, the core material 110 may be made of resin or metal. The core material 110 may also be made of wood, specifically paper.

[0028] The core material 110 may be a material that does not have pores or minute irregularities on its surface. In this case, the core material 110 may be a plate made of resin, metal, or the like.

[0029] The core material 110 preferably has electrolyte resistance. In this case, even when the core material 110 is exposed, the thermosetting resin sheet 100 can be used in an environment where it is in contact with the electrolyte.

[0030] Preferably, the core material 110 has excellent adhesion to the thermosetting resin layer 120. In this case, the thermosetting resin layer 120 is less likely to peel off from the core material 110.

[0031] The core material 110 preferably has low hygroscopicity, for example, lower hygroscopicity than the thermosetting resin layer 120. The reason why low hygroscopicity is preferable is the same as for the thermosetting resin layer 120.

[0032] The above describes the structure of the thermosetting resin sheet 100. Next, the manufacturing method of the thermosetting resin sheet 100 will be explained.

[0033] Figure 2 is a process diagram showing the manufacturing process S10 of the thermosetting resin sheet 100. The manufacturing process S10 includes a preparation process S12 for preparing the core material 110 and the thermosetting resin, and a forming process S14 for forming the thermosetting resin sheet 100 using the prepared core material 110 and the thermosetting resin.

[0034] For example, in forming step S14, the core material 110 is sandwiched between two thermosetting resin sheets, the two thermosetting resin sheets are heated to a temperature above their softening point and below their thermosetting temperature, and the two thermosetting resin sheets are pressed against the core material 110, thereby impregnating the core material 110 with thermosetting resin and forming two thermosetting resin layers 120 that sandwich the core material 110.

[0035] Figure 3 illustrates an example of the formation process S14 shown in Figure 2. The core material 110 is unwound from the first roll body 16, carried on a roll (not shown), and supplied between a pair of heated rolls 14.

[0036] Each of the two thermosetting resin sheets 20 is unwound from a second roll body 18, carried on a roll (not shown), and supplied between a pair of heating rolls 14. A release film 22 is attached to one side of each thermosetting resin sheet 20. The release film 22 has a melting point at least higher than the softening point of the thermosetting resin, more specifically, a melting point higher than the temperature at which the pair of heating rolls 14 heat the thermosetting resin sheet 100. The thermosetting resin sheet 20 is supplied between the pair of heating rolls 14 such that the side 20b opposite to the side 20a to which the release film 22 is attached is in contact with the core material 110, and the release film 22 is in contact with the heating rolls 14.

[0037] The pair of heating rolls 14 are rotationally driven by a drive motor (not shown). The pair of heating rolls 14, however, have heating means such as heaters inside, and their surfaces are heated to a predetermined temperature.

[0038] The pair of heating rolls 14 rotate at a constant speed in opposite directions, pressing the two thermosetting resin sheets 20 against the core material 110, applying pressure to both the core material 110 and the two thermosetting resin sheets 20, and heating them. Specifically, the pair of heating rolls 14 heat the thermosetting resin sheets 20 to a temperature above their softening point and below their thermosetting temperature via the release film 22. As a result, the thermosetting resin impregnates the core material 110, and two thermosetting resin layers 120 sandwiching the core material 110 are formed. In other words, a thermosetting resin sheet 100 is formed. The thermosetting resin sheet 100 is wound into a roll shape by, for example, a winding roll (not shown).

[0039] Furthermore, the pair of heating rolls 14 do not come into direct contact with the thermosetting resin sheet 20, but heat the thermosetting resin sheet 20 via the release film 22, thus preventing the thermosetting resin from adhering to the pair of heating rolls 14.

[0040] For example, if the core material 110 is a nonwoven fabric of polyester resin and the thermosetting resin is epoxy resin, the pair of heating rolls 14 may heat the thermosetting resin to 120°C and apply a pressure of 0.5 MPa to the thermosetting resin. Alternatively, the pair of heating rolls 14 may be rotated to feed the thermosetting resin sheet 100 at a rate of 0.5 m / min.

[0041] Next, we will explain some examples of applications for the thermosetting resin sheet 100.

[0042] Figure 4 shows a battery 200 including a thermosetting resin sheet 100. The battery 200 is a bipolar battery. The battery 200 has a structure in which a positive electrode layer 204 and a negative electrode layer 206 are laminated on respective surfaces of a rectangular plate-shaped or sheet-shaped current collector 202, and a plurality of these are stacked. A separator 208 is provided between the opposing positive electrode layer 204 and negative electrode layer 206. Adjacent current collectors 202 are joined at a constant interval by two thermosetting resin sheets 100. The separator 208 is held between adjacent current collectors 202 by having its peripheral edge sandwiched between the two thermosetting resin sheets 100. The interior of the battery 200 is filled with an electrolytic solution 210 and sealed by the thermosetting resin sheet 100. In other words, in this battery 200, the thermosetting resin sheet 100 functions as both an adhesive sheet and a sealing sheet.

[0043] The current collector 202 is made of a metal such as aluminum, stainless steel, copper, or nickel, and has a low coefficient of linear thermal expansion, specifically 1.0×10 －４ or less, which is a very low coefficient of linear thermal expansion. In contrast, the thermosetting resin sheet 100 has a core material 110, and since the core material 110 has a lower coefficient of linear thermal expansion than the thermosetting resin layer 120, the coefficient of linear thermal expansion of the thermosetting resin sheet 100 as a whole is lower than that in the case where the thermosetting resin sheet 100 does not include the core material 110, that is, it is close to the coefficient of linear thermal expansion of the current collector 202. Therefore, when the thermosetting resin sheet 100 is heated for assembling the battery 200 as described later, distortion of the thermosetting resin layer 120 and thus the thermosetting resin sheet 100 is suppressed, and higher adhesiveness or higher sealing performance can be achieved.

[0044] FIG. 5 is a diagram showing a battery 200X including a thermosetting resin sheet 100X according to a comparative example. The battery 200X is the same as the battery 200 except that the thermosetting resin sheet 100X does not have a core material. FIG. 5(a) shows a state before the thermosetting resin sheet 100X is attached, and FIG. 5(b) shows a state after the thermosetting resin sheet 100X is attached, that is, a state after pressurizing while heating to a temperature equal to or higher than the thermosetting temperature of the thermosetting resin. Since the thermosetting resin sheet 100X according to the comparative example does not have a core material, it tends to spread in the plane direction when heated and pressurized, and can spread both inward and outward as shown in FIG. 5(b). In this case, the battery 200X is formed with a thickness and outer dimensions different from the design. Further, there is a risk that the thermosetting resin sheet 100X may come into contact with the positive electrode layer 204 or the negative electrode layer 206.

[0045] In contrast, in the battery 200 including the thermosetting resin sheet 100, since the thermosetting resin sheet 100 has the core material 110, the spread of the thermosetting resin layer 120 in the plane direction is suppressed, and the problems of the comparative example described above can be avoided.

[0046] Next, a method for manufacturing an assembly will be described. This method can be regarded as a bonding method for two members, and can also be regarded as a sealing method between two members.

[0047] FIG. 6 is a process diagram showing manufacturing step S20 of an assembly. Manufacturing step S20 includes a preparation step S22 of preparing component parts of the assembly, and an assembly step S24 of assembling the prepared components.

[0048] When manufacturing the assembly shown in FIG. 1, in preparation step S22, the thermosetting resin sheet 100, the first member 10, and the second member 12 are prepared. In assembly step S24, the thermosetting resin sheet 100 is arranged between the first member 10 and the second member 12, these are sandwiched and pressurized using a predetermined jig or the like, and the thermosetting resin sheet 100 is heated via the members 10 and 12 using a predetermined heating device to soften and solidify the thermosetting resin layer 120 thereof.

[0049] For example, in assembly step S24, the heating device may heat the thermosetting resin sheet 100 to a temperature above the thermosetting temperature of its thermosetting resin layer 120 but below the melting point of the core material 110. In this case, when the temperature of the thermosetting resin layer 120 rises above its softening point, the thermosetting resin layer 120 softens, and the curable resin penetrates into the fine irregularities on the surfaces of the members 10 and 12. In this state, the temperature of the thermosetting resin layer 120 rises above its thermosetting temperature, and the thermosetting resin layer 120 solidifies. As a result, the first member 10 and the second member 12 are joined via the two thermosetting resin sheets 100. Alternatively, the space between the first member 10 and the second member 12 is sealed. Since the core material 110 does not melt, the shape of the core material 110 can be maintained.

[0050] For example, in assembly step S24, the heating device may heat the thermosetting resin sheet 100 to a first temperature for a predetermined time or longer, and then heat it to a second temperature higher than the first temperature.

[0051] The first temperature may be above the softening point temperature of the thermosetting resin layer 120 and below the thermosetting temperature of the thermosetting resin layer 120, and the second temperature may be above the thermosetting temperature of the thermosetting resin layer 120 and below the melting point of the core material 110. In other words, the thermosetting resin sheet 100 may be heated so that the thermosetting resin layer 120 remains in a softened state for a relatively long time. In this case, the thermosetting resin can be reliably made to penetrate the fine irregularities of the current collector 202.

[0052] Both the first and second temperatures may be above the thermosetting temperature of the thermosetting resin layer 120 but below the melting point of the core material 110. In other words, the thermosetting resin sheet 100 may be heated to a relatively low temperature first, and then to a relatively high temperature, although both temperatures are above the thermosetting temperature.

[0053] In this case, compared to heating to the second temperature from the beginning, the thermosetting resin layer 120 remains soft for a longer period, allowing the thermosetting resin to penetrate reliably through the fine irregularities of the current collector 202. Furthermore, compared to continuing to heat at the first temperature, i.e., not heating to the second temperature, the thermosetting resin layer 120 can be cured in a shorter time, thereby shortening the manufacturing time of the battery 200. In addition, the unreacted portion of the thermosetting resin layer 120 can be reduced or eliminated, increasing the strength of the thermosetting resin layer 120 and, consequently, the thermosetting resin sheet 100.

[0054] Next, when manufacturing the battery 200 shown in Figure 4, in preparation step S22, a thermosetting resin sheet 100, a current collector 202, a positive electrode layer 204, a negative electrode layer 206, a separator 208, and an electrolyte 210 are prepared. In assembly step S24, two thermosetting resin sheets 100 are sandwiched together with adjacent current collectors 202 using a predetermined jig and pressed, and the thermosetting resin sheets 100 are heated via the current collectors 202 using a predetermined heating device to soften and solidify the thermosetting resin layer 120.

[0055] For example, in assembly step S24, the heating device may be heated in the same manner as when manufacturing the assembly shown in Figure 1.

[0056] In other words, the heating device may heat the thermosetting resin sheet 100 to a temperature above the thermosetting temperature of the thermosetting resin layer 120 and below the melting point of the core material 110. Alternatively, the heating device may heat the thermosetting resin sheet 100 to a first temperature for a predetermined time or longer, and then heat it to a second temperature higher than the first temperature. The first temperature may be above the softening point temperature of the thermosetting resin layer 120 and below the thermosetting temperature of the thermosetting resin layer 120, and the second temperature may be above the thermosetting temperature of the thermosetting resin layer 120 and below the melting point of the core material 110. Alternatively, both the first and second temperatures may be above the thermosetting temperature of the thermosetting resin layer 120 and below the melting point of the core material 110.

[0057] The present disclosure has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure. Such modifications will be described below.

[0058] (Modified Example) Figure 7 is a cross-sectional view of a thermosetting resin sheet 100 according to a modified example. Figure 7 corresponds to Figure 1. In this example, the core material 110 has a double-layer structure. Specifically, the core material 110 includes an inner portion 110a and an outer portion 110b that sandwiches the inner portion 110a.

[0059] Figure 8 is a cross-sectional view showing a single fiber among many fibers in a case where the core material 110 of a thermosetting resin sheet 100 according to another modified example is a fibrous structure. In this example, each fiber has a double structure. Specifically, the fibers of the core material 110 include an inner string-like portion 110a located on the inside and a hollow string-like outer portion 110b that surrounds the inner portion 110a.

[0060] These core materials 110 have a lower coefficient of linear thermal expansion than the thermosetting resin layer 120, at least in the inner portion 110a.

[0061] Preferably, the inner portion 110a has a melting point higher than the thermosetting temperature of the thermosetting resin layer 120. The outer portion 110b has a melting point lower than the inner portion 110a. The outer portion 110b may have a melting point equal to or lower than the thermosetting temperature of the thermosetting resin layer 120. In this case, the outer portion 110b may be thinner than the inner portion 110a. When the thermosetting resin sheet 100 is installed between the first member 10 and the second member 12, the thermosetting resin sheet 100 is heated to a temperature above the thermosetting temperature of the thermosetting resin layer 120 and above the melting point of the outer portion 110b, but below the melting point of the inner portion 110a. As a result, the inner portion 110a does not melt, and the shape of the core material 110 can be maintained. The outer portion 110b melts and is firmly bonded to the thermosetting resin layer 120. In other words, the core material 110 can maintain its shape and bond firmly with the thermosetting resin layer 120.

[0062] The inner portion 110a may be formed of a polyester resin, such as PET. The outer portion 110b may be formed of polyethylene, which has a lower melting point than polyester resins. Since polyethylene is compatible with thermosetting resins, good heat welding (impregnation) between the outer portion 110b and the thermosetting resin layer 120 is possible.

[0063] The above embodiments and variations can be generalized to obtain the following embodiments.

[0064] [Aspect 1] A thermosetting resin sheet having a sheet-like core material whose coefficient of thermal expansion is lower than that of the thermosetting resin.

[0065] [Aspect 2] The thermosetting resin sheet according to aspect 1, wherein the melting point of the core material is higher than the thermosetting temperature of the thermosetting resin.

[0066] [Aspect 3] The thermosetting resin sheet according to aspect 1 or 2, wherein the heat resistance temperature of the core material is higher than the thermosetting temperature of the thermosetting resin.

[0067] [Aspect 4] The thermosetting resin sheet according to any one of aspects 1 to 3, wherein the core material is resin.

[0068] [Aspect 5] The thermosetting resin sheet according to any one of aspects 1 to 4, wherein the core material is a fibrous structure.

[0069] [Aspect 6] A thermosetting resin sheet according to any one of aspects 1 to 5, wherein the core material is impregnated with a thermosetting resin.

[0070] [Aspect 7] The core material is a fibrous structure, and each fiber has a double structure including an inner portion with a melting point higher than the thermosetting temperature of the thermosetting resin and an outer portion with a melting point lower than the inner portion, wherein the melting point of the outer portion is the same as or lower than the thermosetting temperature of the thermosetting resin, the thermosetting resin sheet according to aspect 1.

[0071] [Aspect 8] A method for manufacturing a thermosetting resin sheet according to any one of aspects 1 to 7, comprising sandwiching the core material between sheets of the thermosetting resin.

[0072] [Aspect 9] A method for manufacturing a thermosetting resin sheet according to any one of aspects 1 to 7, comprising immersing the core material in the thermosetting resin.

[0073] [Aspect 10] A method for manufacturing a battery, comprising preparing components including a current collector and a thermosetting resin sheet as described in any one of aspects 1 to 7, and assembling the prepared components, wherein the assembly includes heating the thermosetting resin sheet while sandwiching it between current collectors.

[0074] [Aspect 11] The method for manufacturing a battery according to aspect 10, wherein the heating includes heating to a temperature above the thermosetting temperature of the thermosetting resin and below the melting point of the core material.

[0075] [Aspect 12] The method for manufacturing a battery according to aspect 10, wherein the heating includes heating to a first temperature which is above the softening point temperature of the thermosetting resin and below the thermosetting temperature of the thermosetting resin for a predetermined time or longer, and then heating to a second temperature which is above the thermosetting temperature of the thermosetting resin and below the melting point of the core material.

[0076] [Aspect 13] The method for manufacturing a battery according to aspect 10, wherein the heating includes heating to a first temperature which is above the thermosetting temperature of the thermosetting resin and below the melting point of the core material for a predetermined time or longer, and then heating to a second temperature which is higher than the first temperature and below the melting point of the core material.

[0077] This disclosure can be used for thermosetting resin sheets, methods for manufacturing thermosetting resin sheets, and methods for manufacturing batteries.

[0078] Reference Signs List 100 thermosetting resin sheet, 110 core material, 110a inner part, 110b outer part, 120 thermosetting resin layer, 200 battery, 202 current collector.

Claims

1. A thermosetting resin sheet having a sheet-like core material whose coefficient of thermal expansion is lower than that of the thermosetting resin.

2. The thermosetting resin sheet according to claim 1, wherein the melting point of the core material is higher than the thermosetting temperature of the thermosetting resin.

3. The thermosetting resin sheet according to claim 1 or 2, wherein the heat resistance temperature of the core material is higher than the thermosetting temperature of the thermosetting resin.

4. The thermosetting resin sheet according to any one of claims 1 to 3, wherein the core material is a resin.

5. The thermosetting resin sheet according to any one of claims 1 to 3, wherein the core material is a fibrous structure.

6. The thermosetting resin sheet according to any one of claims 1 to 5, wherein the core material is impregnated with a thermosetting resin.

7. The core material is a fibrous structure, and each fiber has a double structure including an inner portion with a melting point higher than the thermosetting temperature of the thermosetting resin and an outer portion with a melting point lower than the inner portion, wherein the melting point of the outer portion is the same as or lower than the thermosetting temperature of the thermosetting resin, the thermosetting resin sheet according to claim 1.

8. A method for manufacturing a thermosetting resin sheet according to any one of claims 1 to 7, comprising sandwiching the core material between sheets of the thermosetting resin.

9. A method for manufacturing a thermosetting resin sheet according to any one of claims 1 to 7, comprising immersing the core material in the thermosetting resin.

10. A method for manufacturing a battery, comprising preparing components including a current collector and a thermosetting resin sheet according to any one of claims 1 to 7, and assembling the prepared components, wherein the assembly includes heating the thermosetting resin sheet while sandwiching it between current collectors.

11. The method for manufacturing a battery according to claim 10, wherein the heating includes heating to a temperature above the thermosetting temperature of the thermosetting resin and below the melting point of the core material.

12. The method for manufacturing a battery according to claim 10, wherein the heating includes heating to a first temperature which is above the softening point temperature of the thermosetting resin and below the thermosetting temperature of the thermosetting resin for a predetermined time or longer, and then heating to a second temperature which is above the thermosetting temperature of the thermosetting resin and below the melting point of the core material.

13. The method for manufacturing a battery according to claim 10, wherein the heating includes heating to a first temperature which is above the thermosetting temperature of the thermosetting resin and below the melting point of the core material for a predetermined time or longer, and then heating to a second temperature which is higher than the first temperature and below the melting point of the core material.

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