Method for manufacturing tab lead, tab lead, electrochemical device, battery, and capacitor

Abstract

A method for manufacturing a tab lead comprising: a lead conductor having a first main surface and a second main surface opposite to the first main surface; and a resin portion that exposes both ends of the lead conductor and covers the first main surface, the second main surface, and both side surfaces between both the ends of the lead conductor, wherein a step for forming the resin portion includes filling a mold with a thermosetting composition.

Description

Tab lead manufacturing method, tab lead, electrochemical device, battery and capacitor

[0001] The present invention relates to a tab lead manufacturing method, a tab lead, an electrochemical device, a battery, and a capacitor. Specifically, the present invention relates to a tab lead manufacturing method, a tab lead, an electrochemical device, a battery, and a capacitor, which can improve the sealing performance in an electrochemical device.

[0002] Batteries are known that have a structure in which a positive electrode, a negative electrode, an electrolyte, and the like are sealed in a packaging material, and lead wires are connected to each of the positive and negative electrodes (see Patent Documents 1 and 2). A portion of the lead wire is exposed to the outside of the packaging material. This lead wire is called a tab lead, and has a structure in which a sealant formed by two thermoplastic resin films (sealant films) bonded to each other so as to sandwich the lead conductor is disposed in a partial area of ​​the lead conductor. In the battery, the sealant is disposed so as to seal the gap between the packaging material and the lead conductor.

[0003] JP 2003-7268 A JP 2019-220295 A

[0004] However, it has been found that there is room for further improvement in the conventional techniques including those described in Patent Documents 1 and 2, from the viewpoint of improving the sealing properties of electrochemical devices such as batteries.

[0005] An object of the present invention is to provide a tab lead manufacturing method capable of improving the sealing performance in an electrochemical device, a tab lead, an electrochemical device, a battery, and a capacitor.

[0006] As a result of extensive research, the present inventors discovered that applying a thermosetting resin to a resin portion of a tab lead can improve the sealing performance of an electrochemical device, and thus completed the present invention. The present invention provides the following methods for manufacturing a tab lead: 1. A method for manufacturing a tab lead having a lead conductor with a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between both ends of the lead conductor while exposing both ends of the lead conductor, wherein the step of forming the resin portion includes filling a mold with a thermosetting composition. 2. The method according to 1, wherein the thermosetting composition includes: (A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1), or a compound represented by the following formula (A2) or (A3), and (B) a thermal polymerization initiator. (In formula (A1), V １０１ is a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 12 ring carbon atoms, a substituted or unsubstituted divalent alicyclic hydrocarbon group having 5 to 12 ring carbon atoms, or a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. p represents the average number of constituent units. When p is 2 or more, two or more V １０１ may be the same or different.) (In formula (A2), R １１１ and R １１５ are each independently a hydrogen atom or a methyl group. １１２ is an alkylene group having 1 to 20 carbon atoms. １１３ and R １１４ are each independently an alkylene group having 1 to 30 carbon atoms. １１２ represents an integer of 0 or 1. １１３ represents an integer from 0 to 30. (In formula (A3), R １２１ is an alkylene group having 1 to 6 carbon atoms. １２２ is a hydrogen atom or a methyl group. １２０ is 3 or 4. １２１ represents an integer of 0 to 15. １２０ If is 3, Z １２０is a substituted or unsubstituted trivalent aliphatic hydrocarbon group having 3 to 10 carbon atoms. １２０ If is 4, Z １２０ is a substituted or unsubstituted tetravalent aliphatic hydrocarbon group having 5 to 10 carbon atoms.) 3. The method according to 1 or 2, wherein, in the step of forming the resin portion, a part or all of the lead conductor is inserted into the mold filled with a thermosetting composition. 4. A tab lead manufactured by any of the methods 1 to 3. 5. A tab lead having a lead conductor having a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between the both ends of the lead conductor while exposing both ends of the lead conductor, wherein the resin portion contains a thermosetting resin. 6. The tab lead according to 5, wherein the resin portion is constituted by a cured product of a thermosetting composition, wherein the thermosetting composition contains (A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1) or a compound represented by the following formula (A2) or (A3), and (B) a thermal polymerization initiator. (In formula (A1), V １０１ is a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 12 ring carbon atoms, a substituted or unsubstituted divalent alicyclic hydrocarbon group having 5 to 12 ring carbon atoms, or a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. p represents the average number of constituent units. When p is 2 or more, two or more V １０１ may be the same or different.) (In formula (A2), R １１１ and R １１５ are each independently a hydrogen atom or a methyl group. １１２ is an alkylene group having 1 to 20 carbon atoms. １１３ and R １１４ are each independently an alkylene group having 1 to 30 carbon atoms. １１２ represents an integer of 0 or 1. １１３ represents an integer from 0 to 30. (In formula (A3), R １２１ is an alkylene group having 1 to 6 carbon atoms.１２２ is a hydrogen atom or a methyl group. １２０ is 3 or 4. １２１ represents an integer of 0 to 15. １２０ If is 3, Z １２０ is a substituted or unsubstituted trivalent aliphatic hydrocarbon group having 3 to 10 carbon atoms. １２０ If is 4, Z １２０ is a substituted or unsubstituted tetravalent aliphatic hydrocarbon group having 5 to 10 carbon atoms. 7. The tab lead according to any one of 4 to 6, wherein the resin portion has a uniform composition throughout the entire resin portion. 8. An electrochemical device comprising the tab lead according to any one of 4 to 7. 9. A battery comprising the tab lead according to any one of 4 to 7. 10. A capacitor comprising the tab lead according to any one of 4 to 7.

[0007] According to the present invention, it is possible to provide a tab lead manufacturing method capable of improving the sealing performance in an electrochemical device, a tab lead, an electrochemical device, a battery, and a capacitor.

[0008] Fig. 1 is a plan view showing an example of a tab lead manufactured by a tab lead manufacturing method according to an embodiment of the present invention. Fig. 2 is a cross-sectional view taken along the line (ii)-(ii) in Fig. 1. Fig. 3 is a cross-sectional view of a tab lead according to a conventional technique, similar to Fig. 2. Fig. 4 is a schematic cross-sectional view of a filling device of a molding machine that can be used in the step of forming a resin portion. Fig. 5 is a schematic cross-sectional view of a mold that can be used in the step of forming a resin portion. Fig. 6 is a diagram showing an example of the relationship between the viscosity of a thermosetting composition and time. Fig. 7 is a diagram illustrating the schematic configuration of an electrochemical device according to an embodiment.

[0009] The tab lead manufacturing method, tab lead, electrochemical device, battery, and capacitor of the present invention are described in detail below. In this specification, "x to y" represents a numerical range of "greater than or equal to x and less than or equal to y." The upper and lower limits of numerical ranges can be combined arbitrarily. Furthermore, among the individual embodiments of the aspects of the present invention described below, two or more embodiments that are not mutually exclusive can be combined, and an embodiment combining two or more embodiments is also an embodiment of the aspects of the present invention.

[0010] In this specification, the "number of carbon atoms XX to YY" in the expression "substituted or unsubstituted ZZ group having carbon atoms XX to YY" represents the number of carbon atoms when the ZZ group is unsubstituted, and does not include the number of carbon atoms of the substituent when the ZZ group is substituted. Here, "YY" is larger than "XX", and "XX" and "YY" each represent an integer of 1 or more.

[0011] In this specification, the "number of atoms XX to YY" in the expression "a substituted or unsubstituted ZZ group having the number of atoms XX to YY" represents the number of atoms when the ZZ group is unsubstituted, and does not include the number of atoms of substituents when the ZZ group is substituted. Here, "YY" is larger than "XX", and "XX" and "YY" each represent an integer of 1 or more.

[0012] In this specification, examples of the substituent (hereinafter also referred to as an arbitrary substituent) in the case of "substituted or unsubstituted" include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen atom, a hydroxyl group, an oxirane group, a methacryloyloxy group, an acryloyloxy group, -O-(R ９０１ ), -S-(R ９０２ ), -N(R ９０３ ) (R ９０４ ) etc. ９０１ ~R ９０４ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms (preferably linear or branched) include a methyl group, an ethyl group, a propyl group (e.g., n-propyl group, isopropyl group), a butyl group (e.g., n-butyl group, isobutyl group, s-butyl group, t-butyl group), a pentyl group (e.g., n-pentyl), and a hexyl group. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, and a hexyloxy group. Examples of the halogen atom include a fluorine atom, a bromine atom, and an iodine atom.

[0013] In the case of "substituted or unsubstituted," "unsubstituted" means that the group is not substituted with the above-mentioned substituents and has a hydrogen atom bonded thereto.

[0014] In this specification, acrylate and methacrylate are collectively referred to as (meth)acrylate, acrylic acid and methacrylic acid are collectively referred to as (meth)acrylic acid, acrylo and methacrylo are collectively referred to as (meth)acrylo, acrylic and methacrylic are collectively referred to as (meth)acrylic, and methacryloyl and acryloyl groups are collectively referred to as (meth)acryloyl groups.

[0015] 1. Method for Manufacturing Tab Lead According to one aspect of the present invention, there is provided a method for manufacturing a tab lead having a lead conductor having a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between the end portions of the lead conductor while exposing the end portions of the lead conductor, wherein the step of forming the resin portion includes filling a mold with a thermosetting composition. According to this aspect, it is possible to manufacture a tab lead that can improve the sealing performance of an electrochemical device.

[0016] FIG. 1 is a plan view showing an example of a tab lead manufactured according to this embodiment. FIG. 2 is a cross-sectional view taken along line (ii)-(ii) in FIG. 1 . The tab lead 1 shown in FIGS. 1 and 2 includes a lead conductor 2 and a resin portion 3. The lead conductor 2 has a first main surface 2a and a second main surface 2b opposite the first main surface 2a. The planar shape of the lead conductor 2 is not limited to the rectangular shape shown in the figure, and various planar shapes can be given depending on the purpose and application. The resin portion 3 covers the first main surface 2a, the second main surface 2b, and both side surfaces 2c between the lead conductor 2 and both ends in the vertical direction in FIG. 1 while exposing both ends. The planar shape of the resin portion 3 is not limited to the rectangular shape shown in the figure, and various planar shapes can be given depending on the purpose and application. Both ends of the lead conductor 2 are electrically connected to conductive parts such as electrodes and terminals, and therefore are exposed without the resin portion 3 formed thereon. In an electrochemical device (not shown), the resin portion 3 is arranged so as to seal the gap between the lead conductor 2 and a packaging material in which the positive electrode, negative electrode, electrolyte, etc. are sealed.

[0017] In this embodiment, when manufacturing the tab lead 1 as described above, the step of forming the resin portion 3 includes filling a mold with a thermosetting composition, thereby improving the sealing performance of the electrochemical device. In this regard, for comparison, a conventional technique is described with reference to FIG. 3 . In the conventional technique, the resin portion (sealing material) is formed by two thermoplastic resin films (sealant films) 4, 5 bonded to each other so as to sandwich the lead conductor 2. In this case, it is particularly difficult to achieve close contact between the thermoplastic resin films 4, 5 and both side surfaces 2 c of the lead conductor 2, and gaps are likely to occur. To prevent such gaps, it is possible to form the thermoplastic resin films 4, 5 thicker, but this would increase the overall thickness of the battery, which is limiting. For ease of explanation, the thermoplastic resin films 4, 5 are each shown as a single-layer structure in FIG. 3 . However, in practice, they typically have a laminated structure with three or more layers. In contrast, in this embodiment, the thermosetting composition (material for forming the resin portion 3) filled into the mold has fluidity before curing, thereby improving molding accuracy using the mold. Therefore, the resin portion 3 can be molded to fit the shape of the lead conductor 2 with high precision. As a result, as shown in FIG. 2 , the resin portion 3 can be formed to adhere well to both side surfaces 2c of the lead conductor 2. This improves the hermetic seal of the electrochemical device. This effect is not dependent on the thickness of the resin portion 3, and is effectively exerted even when the resin portion 3 is formed thin. Therefore, the battery can be made lighter and more compact (reduced in volume). Furthermore, this embodiment also reduces the number of steps required to manufacture the tab lead 1 compared to conventional techniques.

[0018] The material of the lead conductor 2 is not particularly limited as long as it is a conductor. In one embodiment, the lead conductor 2 is made of a metal. In one embodiment, the lead conductor 2 is made of aluminum (Al), nickel (Ni), an aluminum alloy, a nickel alloy, nickel-plated copper, or nickel-clad copper. In one embodiment, when the electrochemical device is a lithium ion battery or a lithium ion capacitor, aluminum or an aluminum alloy is used for the lead conductor 2 on the positive electrode side, and nickel, a nickel alloy, or nickel-plated copper is used for the lead conductor 2 on the negative electrode side. The surface of the lead conductor 2 may be subjected to a surface treatment (e.g., chromate treatment) for the purpose of improving adhesion, or the like, or may not be subjected to a surface treatment.

[0019] There is no particular limitation on the thickness of the lead conductor 2. In one embodiment, the thickness of the lead conductor 2 is 0.05 to 1.5 mm. The lead conductor 2 is obtained, for example, by cutting a metal foil to a predetermined size.

[0020] The resin portion 3 is arranged to cover the outer periphery of a portion of the lead conductor 2, excluding the regions including both ends in the vertical direction in Fig. 1. As shown in Fig. 2, the resin portion 3 is formed in an annular shape so as to surround the outer periphery of the lead conductor 2. The entire inner periphery of the resin portion 3 is in direct contact with the lead conductor 2.

[0021] In one embodiment, the thickness of the resin portion 3 on the first main surface 2a of the lead conductor 2 and / or the thickness of the resin portion 3 on the second main surface 2b of the lead conductor 2 is 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, 80 μm or more, 90 μm or more, or 100 μm or more, and is 300 μm or less, 250 μm or less, or 200 μm or less. Furthermore, as described above, in this embodiment, the sealing performance of the electrochemical device can be improved even when the resin portion 3 is formed thin. By forming the resin portion 3 thin, the electrochemical device can be made lighter and more compact (reduced in volume). From this perspective, in one embodiment, the thickness of the resin part 3 on the first main surface 2a of the lead conductor 2 and / or the thickness of the resin part 3 on the second main surface 2b of the lead conductor 2 is 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, or 50 μm or less.

[0022] In one embodiment, the composition of the resin portion 3 is uniform throughout the entire resin portion 3. Since the resin portion 3 is manufactured using a mold, it does not usually have a layered structure as in conventional techniques.

[0023] In one embodiment, the thermosetting composition contains a thermosetting resin. Examples of thermosetting resins include acrylic resins, phenolic resins, epoxy resins, unsaturated polyester resins, melamine resins, and polyurethanes. These may be used alone or in combination of two or more. In one embodiment, the thermosetting composition contains an acrylic resin as the thermosetting resin. In one embodiment, the thermosetting composition contains a thermosetting resin and a thermal polymerization initiator. The thermal polymerization initiator can be selected appropriately depending on the type of thermosetting resin used, etc. The "thermosetting resin" contained in the thermosetting composition filled into the mold is in an uncured state or in a state in which curing is not complete.

[0024] An example of a preferred thermosetting composition (also referred to as "thermosetting composition α") will be described below. Regarding thermosetting composition α, reference can be made to the thermosetting compositions for injection molding described in Japanese Patent Application Nos. 2023-513034 and 2023-513037.

[0025] In one embodiment, the thermosetting composition α contains: (A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1), or a compound represented by the following formula (A2) or (A3); and (B) a thermal polymerization initiator.

[0026]

[0027] (In formula (A1), V １０１ is a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 12 ring carbon atoms, a substituted or unsubstituted divalent alicyclic hydrocarbon group having 5 to 12 ring carbon atoms, or a substituted or unsubstituted divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms. p represents the average number of constituent units. When p is 2 or more, two or more V １０１ may be the same or different.)

[0028]

[0029] (In formula (A2), R １１１ and R １１５ are each independently a hydrogen atom or a methyl group. １１２ is an alkylene group having 1 to 20 carbon atoms. １１３ and R １１４ are each independently an alkylene group having 1 to 30 carbon atoms. １１２ represents an integer of 0 or 1. １１３ represents an integer from 0 to 30.

[0030]

[0031] (In formula (A3), R １２１ is an alkylene group having 1 to 6 carbon atoms. １２２ is a hydrogen atom or a methyl group. １２０ is 3 or 4. １２１ represents an integer of 0 to 15. １２０ If is 3, Z １２０ is a substituted or unsubstituted trivalent aliphatic hydrocarbon group having 3 to 10 carbon atoms. １２０ If is 4, Z １２０is a substituted or unsubstituted tetravalent aliphatic hydrocarbon group having 5 to 10 carbon atoms.

[0032] In one embodiment, the component (A) has a viscosity of 10 seconds at 25°C measured in accordance with JIS K7117-2. －１ The viscosity at a shear rate of 0.001 Pa·s or more and 80 Pa·s or less.

[0033] The thermal polymerization initiator of component (A) refers to a compound that generates active species such as radicals or cations upon heating. By including the thermal polymerization initiator of component (B), a stable molded product can be obtained (for example, the curing time can be shortened and the curing time margin can be narrowed). Component (B) is not particularly limited, but examples thereof include radical polymerization initiators. Examples of radical polymerization initiators include, but are not particularly limited to, ketone peroxides, hydroperoxides, diacyl peroxides, dialkyl peroxides, peroxyketals, alkyl peresters (peroxyesters), and peroxycarbonates.

[0034] The content of component (B) is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, and even more preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the total of the components other than component (B).

[0035] In one embodiment, the thermosetting composition α further includes (C) one or more selected from the group consisting of a compound represented by the following formula (C1), and a polymer including one or more structural units represented by the following formula (C2) and one or more structural units represented by the following formula (C3):

[0036]

[0037] (In formula (C1), Y ３０１ , Y ３０２ , and Y ３０３ each independently represents an alkylene group having 1 to 10 carbon atoms substituted with a hydroxy group, or an alkylene group having 1 to 10 carbon atoms. ３０１ and X ３０２each independently represents an alkylene group having 1 to 10 carbon atoms or an alkylene group having 1 to 10 carbon atoms substituted with a hydroxy group; ３０１ -Z ３０２ -Z ３０３ - or -Z ３０４ -Z ３０５ -Z ３０６ Indicates -. ３０１ and R ３０２ each independently represents a hydrogen atom or a methyl group. ３０１ and Z ３０３ each independently represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 12 ring carbon atoms, or a substituted or unsubstituted divalent alicyclic hydrocarbon group having 6 to 12 ring carbon atoms. ３０２ is -C(CH ３ ) ２ -, -C(CF ３ ) ２ -, -CH ２ -, -S(=O) ２ represents -, -O- or -C(=O)-. ３０４ and Z ３０６ each independently represents a divalent organic group. ３０５ represents a substituted or unsubstituted divalent fluorene or a substituted or unsubstituted divalent naphthalene. a and b each independently represent an integer of 0 to 10. c, d, and e each independently represent 0 or 1. f represents an integer of 1 to 5. a + (b × f) + c + d + (e × f) is 2 or more.

[0038]

[0039] (In formula (C2), R ４０１ is a hydrogen atom or a methyl group. ４０２ is a hydrogen atom or a methyl group. ４０３ represents an alkyl group having 2 to 18 carbon atoms, -R ４１１ OR ４１２ , or -R ４１３ SR ４１４ It is. ４１１ and R ４１３ are each independently an alkylene group having 1 to 30 carbon atoms. ４１２ and R４１４ are each independently an alkyl group having 1 to 30 carbon atoms.

[0040] In one embodiment, component (C) includes a polymer containing one or more structural units represented by formula (C2) and one or more structural units represented by formula (C3). In one embodiment, the polymer containing one or more structural units represented by formula (C2) and one or more structural units represented by formula (C3) is a block copolymer. In one embodiment, component (C) includes a compound represented by formula (C1).

[0041] In one embodiment, the thermosetting composition α has a content of component (C) of 5% by mass or more and 50% by mass or less, based on 100% by mass of the total of components other than component (B).

[0042] In one embodiment, the thermosetting composition α further contains (D) a compound represented by the following formula (D1):

[0043] (In formula (D1), R ５０１ is a hydrogen atom or a methyl group. ５０２ is a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, excluding compounds corresponding to component (A).

[0044] From the viewpoint of further improving the adhesion between the resin part 3 and the lead conductor 2 and the adhesion between the resin part 3 and the packaging material, it is preferable that the component (D) contains an acrylate compound or methacrylate compound having a glycidyl group.

[0045] When component (D) is contained, the content of component (D) is preferably 1 to 80 mass%, and more preferably 10 to 60 mass%, based on 100 mass% of the total of components other than component (B).

[0046] In one embodiment, the thermosetting composition α may further include an inorganic filler as component (E). This improves flame retardancy. Component (E) is preferably one or more selected from the group consisting of magnesium hydroxide and aluminum hydroxide, and more preferably aluminum hydroxide.

[0047] In one embodiment, the thermosetting composition α may further contain a phosphate ester-based flame retardant as component (F), which can improve flame retardancy.

[0048] In one embodiment, the thermosetting composition α may further contain additives to the extent that the effects of the present invention are not impaired. Examples of additives include antioxidants, light stabilizers, flame retardants other than phosphate ester-based flame retardants, ultraviolet absorbers, plasticizers, colorants, antistatic agents, lubricants, release agents, leveling agents, and antifoaming agents. Known additives can be used.

[0049] In one embodiment, the thermosetting composition α essentially consists of component (A) and component (B), and optionally components (C) to (F) and additives, and may contain other inevitable impurities as long as the effects of the present invention are not impaired. In one embodiment, for example, 40% by weight or more, 95% by weight or more, 99% by weight or more, or 100% by mass of the thermosetting composition α may consist of component (A) and component (B), components (A) to (D), components (A) to (F), or component (A) and component (B), and optionally components (C) to (F) and additives.

[0050] In one embodiment, the thermosetting composition α has a hardness of 10 s at 25°C measured in accordance with JIS K7117-2. －１ The viscosity at a shear rate of 0.001 Pa·s or more and 600 Pa·s or less.

[0051] Next, an example of a process for forming the resin portion 3 will be described. In one embodiment, the process for forming the resin portion 3 includes a process of supplying a thermosetting composition into a plunger (supplying process), a process of filling the supplied thermosetting composition with the plunger into a molded product portion (cavity) of a mold having a gauge pressure of −90 kPa or less (vacuum pressure of 10 kPa) and an oxygen content of 0.2 × cavity volume / 22.4 mol or less, or a gauge pressure of −90 kPa or less (vacuum pressure of 10 kPa) and an oxygen content of 0.2 × cavity volume / 22.4 mol or less (filling process), and a process of thermally curing the filled thermosetting composition within the molded product portion (curing process). The process for forming the resin portion 3 may further include a process of extruding the thermosetting resin from the molded product portion (cavity) (demolding process).

[0052] As a molding method, from the viewpoint of preventing only the resin component of the thermosetting composition from being filled, transfer molding such as LTM (Liquid Transfer Molding), compression molding, or injection molding such as LIM (Liquid Injection Molding) is preferred. Prepolymerization may be performed.

[0053] In transfer molding, a transfer molding machine (e.g., a G-Line liquid transfer molding machine) can be used, for example, with a clamping force of 5 to 20 kN, a molding temperature of 60 to 190°C, and a molding time of 30 to 500 seconds, preferably a molding temperature of 70 to 180°C, and a molding time of 30 to 180 seconds. Post-curing may be performed, for example, at 150 to 185°C for 0.5 to 24 hours.

[0054] In liquid injection molding, for example, a liquid thermosetting resin injection molding machine LA-40S is used, and molding can be performed, for example, at a mold clamping force of 10 kN to 40 kN, a molding temperature of 60 to 190°C, and a molding time of 30 to 500 seconds, preferably at a molding temperature of 70 to 180°C, and a molding time of 20 to 180 seconds.

[0055] The molding machine preferably includes a plunger and a mold having a molded product portion, and further includes a shut-off nozzle.

[0056] Fig. 4 is a diagram showing one embodiment of a filling device of a molding machine capable of carrying out an injection molding method. The molding machine of Fig. 4 is an injection molding machine having a plunger mechanism for extruding a thermosetting composition into a mold, and includes a filling device 10 having a plunger 11 shown in Fig. 4 and a mold 20 having a cavity 21 shown in Fig. 5(A). Although not shown, the molding machine also includes a pressure reducing device as a degassing means connected to a fine hole for degassing the cavity 21 in the mold 20, a heating device as a heating means connected to the mold 20, and a cooling device. The molding material is a thermosetting composition. In another embodiment, the molding machine may include an inert gas replacement device as a means connected to the fine hole for replacing the air in the cavity in the mold with an inert gas.

[0057] A known filling device having a plunger can be used as the filling device 10. Typically, the filling device 10 having a plunger 11 is provided with a feed section and a check valve function as shown in Fig. 4, and the material introduced from an inlet (not shown) is fed, stirred, and mixed by moving the check valve 12 (which may be in the form of a screw) back and forth. However, in this embodiment, stirring and mixing are not necessary because the thermosetting composition introduced is a homogeneous liquid.

[0058] In the step of filling the cavity with a plunger, the thermosetting composition is preferably filled into the cavity in the mold through a flow path whose temperature is controlled to 50° C. or less. When carried out using the apparatus shown in FIG. 5 , the flow path corresponds to the flow path (not shown) of the thermosetting composition in the filling apparatus 10 and the introduction path in the mold 20.

[0059] In one embodiment, during the process of filling a cavity in a mold with a thermosetting composition filled in a plunger, a flow path (flow path) between the plunger and the cavity includes a gate system that blocks the flow of the curing liquid and the transfer of heat. This will be described below with reference to FIG. 5 . When using the apparatus shown in FIG. 5 , the needle 223 and the opening 222 correspond to the gate system. As described above, the needle 223 moves toward the movable mold 23 and closes the opening 222, thereby cutting off the introduction path 221 just before the heating section 22A. The thermosetting composition introduced into the introduction path 221 remains in the cooling section 22B, blocking the flow of the thermosetting composition and the transfer of heat. Examples of systems that can block the flow of the thermosetting composition and the transfer of heat include a valve gate system and a shut-off nozzle system. The heating device heats the heating section 22A and the movable mold 23. This heating allows the temperature inside the cavity (also referred to as the "cavity temperature") to be set to a predetermined temperature. Preferably, the temperature of the mold 232 that forms the cavity is set to 40°C or higher and 150°C or lower. The cooling device is a device that cools the flow path of the thermosetting composition. Specifically, it is preferable to cool the filling device 10 and the cooling section 22B of the mold 20 to 10°C or higher and 50°C or lower. In the case of injection molding, the needle (not shown) in Figure 4 corresponds to the needle 223 in Figure 5, and the flow path (not shown) in Figure 4 corresponds to the introduction path 221 in Figure 5.

[0060] The supply process is shown in Figure 4. In the case of transfer molding or compression molding, the material can be measured by inserting an appropriate amount of material into plunger 11 using a supply device (not shown), such as a syringe. In the case of injection molding, the thermosetting composition is injected into filling device 10 shown in Figure 4 through an inlet (not shown). The injected thermosetting composition is pushed out into check valve 12, and then a predetermined amount is measured by plunger 11. After measurement is completed or before injection, check valve 12 moves forward, functioning as a check valve when plunger 11 moves. During this time, the flow path is cooled by a cooling device, so the thermosetting composition flows smoothly without hardening.

[0061] The filling step is shown, for example, in FIG. 5(B). When injecting the thermosetting composition into the cavity, it is preferable to reduce the pressure inside the cavity by installing a vent to release air from the cavity or by providing a small hole connected to a pressure reducing device such as the vacuum pipe 240 in FIG. 5 that allows the pressure inside the cavity to be reduced. The reason for this is that during the process of injecting the thermosetting composition into the cavity and completely filling it, the vent is used to release air from the cavity, and reducing the pressure inside the cavity is used to create an air-free state so that the cavity can be completely filled with the thermosetting composition. If this mechanism is not available, it is preferable to have a mechanism (e.g., a vent mechanism) that removes air from the cavity when the material is being filled. To prevent poor curing, the gauge pressure in the cavity when injecting the thermosetting composition into the cavity is preferably −90 kPa or less (vacuum pressure 10 kPa), and the amount of oxygen in the cavity is preferably 0.2 × cavity volume / 22.4 mol or less, or −90 kPa or less (vacuum pressure 10 kPa) and the amount of oxygen in the cavity is preferably 0.2 × cavity volume / 22.4 mol or less. A method for reducing the amount of oxygen in the cavity to 0.2 × cavity volume / 22.4 mol or less is preferably a method of degassing the cavity in the mold using a pressure reducing device connected to a fine hole for degassing the cavity, and replacing the air with an inert gas using an inert gas replacement device connected to a fine hole for replacing the air in the cavity with an inert gas. Furthermore, a sprueless method is preferred for reducing the pressure in the cavity. To mold the thermosetting composition, first, the movable mold 23 is brought close to the fixed mold 22, and the mold is clamped ( FIG. 5(A) ). The movement of the movable mold 23 is temporarily stopped at a position where the elastic member 238 of the movable mold 23 abuts against the elastic member 224 of the fixed mold 22 .

[0062] The thermosetting composition is preferably filled into the cavity by opening the gate of the gate system (moving the needle 223 toward the fixed mold 22) and filling the cavity 21 in the mold with the thermosetting composition. The heating units 22A provided on the movable mold 23 and the fixed mold 22 are constantly heated, and the cavity temperature is set to, for example, 50°C or higher, preferably 50°C to 150°C, and particularly preferably 50°C to 120°C. When using an injection molding machine, when starting injection from the injection unit into the cavity, the nozzle of the shut-off nozzle (or valve gate in some cases) is opened, the plunger of the injection unit is moved, and the thermosetting component is injected into the cavity. When using a transfer molding machine, since the entire material is cured from the plunger to the cavity, it is sufficient for the material to flow into the cavity, and heat exchange does not need to be blocked.

[0063] The curing process is shown, for example, in FIG. 5(C). Once the filling of the cavity 21 with the thermosetting composition is complete, the thermosetting composition begins curing. However, to improve the transferability of the molded product, it is preferable to apply a predetermined pressure to the thermosetting composition during curing. That is, it is preferable to pressurize the plunger 11 to a pressure of 1.0 MPa or more and 30 MPa or less. This pressure applied to the thermosetting composition to improve transferability is called a dwell pressure. The curing process preferably involves dwelling (increasing the pressure applied to the thermosetting composition) after the start of thermal curing and before the completion of curing. After the dwell pressure, the gate of the gate system is closed to perform thermal curing. Specifically, the gate is closed by advancing the needle 223 to close the opening 222. During the molding process, a cooling device is operated to cool the entire flow path of the thermosetting composition, i.e., the filling device 10 of the molding machine and the cooling section 22B provided in the fixed mold 22 of the mold 20. During this process, the entire flow path is preferably maintained at a temperature of 10°C or more and 50°C or less, and particularly preferably at 30°C or less.

[0064] The following describes the holding pressure applied by the plunger 11 and the timing of the start of holding pressure. FIG. 6 is a diagram showing an example of the relationship between the viscosity of a thermosetting composition (particularly thermosetting composition α) and time. In FIG. 6, the period P1 from when the material is injected into the cavity until filling is complete corresponds to the induction period from when heat is applied to the material until curing begins. The curing process is divided into two stages: an early curing stage P2, which occurs after the material begins to harden upon application of heat and until it is completely hardened, and a late curing stage P3, which occurs when curing is completed. The viscosity of the thermosetting composition remains low and unchanged during the induction period P1, shows a significant change from low to high viscosity during the early curing stage P2, and gradually increases at a high viscosity during the late curing stage P3.

[0065] In the initial stage of curing P2, not only does the thermosetting composition change in viscosity as it transforms from a liquid to a solid, but it also changes in volume, causing it to shrink. Therefore, in actual molding, if pressure is not applied to the thermosetting composition, the molded product will have poor transferability. To improve transferability, it is preferable to apply pressure to the thermosetting composition (holding pressure) to adhere the thermosetting composition to the mold 20 and fill the thermosetting composition from the gate portion. Furthermore, to obtain a molded product with high transferability, it is preferable to synchronize the timing of the start of the holding pressure (holding pressure start time T) with the timing of the transition from the induction period P1 to the initial stage of curing P2 of the curing process.

[0066] If the viscosity of the thermosetting composition in the cavity 21 can be detected, the dwell start time T can be determined. In this embodiment, the thermosetting composition begins to shrink at the same time as it thickens in the initial curing stage P2, so it is preferable to detect the time when the shrinkage begins. This allows the dwell start time T to be appropriately determined.

[0067] In the curing step, by holding the pressure under the above-mentioned conditions, sink marks and distortion of the molded product can be prevented and transferability can be improved. After the pressure has been held for a certain period of time, as shown in Figure 5(C), the needle 223 is advanced to close the opening 222, and the thermosetting composition is heated for a certain period of time to completely cure so as to prevent any uncured portions from occurring. Then, the plunger 11 is advanced to fill the cavity 21 of the mold 20 with the thermosetting composition, and the time required for filling t １When the filling is completed, the plunger 11 stops. When the curing of the thermosetting composition starts, the thermosetting composition simultaneously contracts, so the plunger 11, which had stopped after the filling step was completed, starts moving forward again. The time t required from the completion of the filling step until the plunger 11 starts moving forward again due to contraction is ２ The time required for further heating to completely cure the thermosetting composition is defined as t ３ In this case, t １ +t ２ +t ３ The total time required for the filling step and the heat curing step is preferably 0.2 to 3 minutes, and more preferably 0.2 to 2 minutes. If it is less than 0.2 minutes, there is a risk that the curing will be incomplete, and if it is more than 3 minutes, it is not preferable from the viewpoint of mass productivity.

[0068] The demolding step is shown in Fig. 5(D), for example. The cured product in the cavity can be removed by separating the movable mold 23 from the fixed mold 22. If demolding is difficult, an ejector mechanism may be provided in the mold as appropriate. The hardness of the cured product is preferably low, and a Type A durometer hardness according to JIS K7215 of 20 to 80 is preferred, and a hardness of 20 to 70 is more preferred.

[0069] In this manner, the resin portion 3 can be formed as a cured product of the thermosetting composition. That is, the resin portion is made of a cured product of the thermosetting composition.

[0070] In one embodiment, in the step of forming the resin portion 3, a part or all of the lead conductor 2 is inserted into a mold filled with the thermosetting composition. This allows the resin portion 3 to be formed integrally with the lead conductor 2, and further improves adhesion between the lead conductor 2 and the resin portion 3. The "part" of the lead conductor 2 may correspond to the area where the resin portion 3 is formed. When the entire lead conductor 2 is inserted into the mold, it is preferable that portions other than the "part" that may correspond to the area where the resin portion 3 is formed (other portions) do not come into contact with the thermosetting composition. Other portions of the lead conductor 2 can be prevented from coming into contact with the thermosetting composition by, for example, masking or clamping (pressing) the lead conductor 2 with a mold. The amount of press-down by the mold can be adjusted as appropriate so as to prevent resin burrs from occurring in other portions of the lead conductor 2. Note that resin portions may also be formed in other portions of the lead conductor 2, and the resin portions in the other portions may be removed as a post-processing step.

[0071] 2. Tab Lead A tab lead according to one aspect of the present invention is a tab lead manufactured by the tab lead manufacturing method according to one aspect of the present invention. The tab lead of this aspect can improve the sealing performance in an electrochemical device.

[0072] A tab lead according to another aspect of the present invention includes a lead conductor having a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between the end portions of the lead conductor while exposing both end portions of the lead conductor, wherein the resin portion contains a thermosetting resin. The tab lead of this aspect can be manufactured by the manufacturing method of the tab lead according to the aspect of the present invention, and can improve the hermetic sealing in an electrochemical device.

[0073] The description of the tab lead manufacturing method according to one aspect of the present invention is applicable to the configurations of the tab lead according to one aspect of the present invention and the tab lead according to other aspects of the present invention.

[0074] 3. Electrochemical Device (Battery, Capacitor) An electrochemical device according to one aspect of the present invention includes a tab lead according to one aspect of the present invention or a tab lead according to another aspect of the present invention. The electrochemical device of this aspect can improve the sealing performance of the electrochemical device. The electrochemical device may be, for example, a battery, a capacitor, or the like. Examples of batteries include lithium ion batteries (LiBs). Examples of capacitors include electric double layer capacitors (EDLCs), lithium ion capacitors (LICs), and the like.

[0075] A preferred form of electrochemical device is a laminate type (also called a "pouch type") in which electrodes and an electrolytic solution or solid electrolyte are sealed inside a bag-shaped laminate material (also called a "packaging material"). Electrochemical devices can be used, for example, as automotive batteries or storage batteries. In electrochemical devices, tab leads function, for example, as terminal members for extracting electric power. One end of a lead conductor of the tab lead is connected to an electrode arranged inside the packaging material, and the other end is exposed to the outside of the packaging material. A connection terminal of an external device (e.g., a bus bar, etc.) can be connected to this other end. The resin portion of the tab lead is arranged to seal the gap between the packaging material and the lead conductor.

[0076] The schematic configuration of an electrochemical device according to one embodiment will be described with reference to Fig. 7. The electrochemical device includes a packaging material 6 made of a bag-shaped laminate material, various components enclosed within the packaging material 6, and tab leads 1, 1 with portions protruding from the packaging material 6.

[0077] The packaging material 6 is bag-shaped with a sealing portion 6a formed at the upper end. The sheet constituting the packaging material 6 has a three-layer structure in which an outer layer, a metal layer, and an inner layer are laminated in this order, for example. The outer layer is made of, for example, polyethylene terephthalate, the inner layer is made of, for example, polypropylene or polyethylene, and the metal layer is made of, for example, aluminum or stainless steel.

[0078] An electrolyte solution 7 is sealed inside the packaging material 6, and a positive electrode 8, a negative electrode 9, and a separator (not shown) are arranged inside. The positive electrode 8 and the negative electrode 9 are immersed in the electrolyte solution 7, and the separator separates the space in which the positive electrode 8 is arranged from the space in which the negative electrode 9 is arranged. For example, aluminum is used as the positive electrode 8, and for example, nickel, copper, or an alloy thereof is used as the negative electrode 9. Note that a solid electrolyte may be used instead of the electrolyte solution 7.

[0079] Of the two tab leads 1, 1, one tab lead 1 connected to the positive electrode 8 functions as the positive electrode in the electrochemical device, and the other tab lead 1 connected to the negative electrode 9 functions as the negative electrode in the electrochemical device.

[0080] A portion of the outer peripheral surface of the tab lead 1 is in close contact with the sealing portion 6a, and the upper end portion protrudes upward from the packaging material 6. The lower end of the lead conductor 2 serves as an electrode connection portion and is connected to a positive electrode 8 or a negative electrode 9 by, for example, welding. The upper end of the lead conductor 2 serves as a terminal connection portion exposed to the outside from the packaging material 6 and is connected to a connection terminal (not shown) of an external device by, for example, welding. The resin portion 3 covers the first principal surface, the second principal surface, and both side surfaces between both ends of the lead conductor 2 so as to be in close contact with them. The resin portion 3 is also in close contact with the inner surface of the sealing portion 6a of the packaging material 6. This seals the packaging material 6 and prevents leakage of the electrolyte 7 or the like enclosed within the packaging material 6. Furthermore, the resin portion 3, interposed between the lead conductor 2 and the packaging material 6, can ensure insulation between the lead conductor 2 and the packaging material 6.

[0081] Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will readily be able to make numerous modifications to these exemplary embodiments and / or examples without substantially departing from the novel teachings and advantages of the present invention. Accordingly, these numerous modifications are within the scope of the present invention. The contents of all documents cited in this specification and of the applications from which this application claims priority under the Paris Convention are incorporated by reference in their entirety.

Claims

1. A method for manufacturing a tab lead having a lead conductor with a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between both ends of the lead conductor while exposing both ends of the lead conductor, wherein the step of forming the resin portion includes filling a thermosetting composition into a mold.

2. The method according to claim 1, wherein the thermosetting composition contains (A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1), or a compound represented by the following formula (A2) or (A3), and (B) a thermal polymerization initiator. (In formula (A1), １０１ V is a divalent aromatic hydrocarbon group having 6 to 12 ring-forming carbon atoms which may be substituted or unsubstituted, a divalent alicyclic hydrocarbon group having 5 to 12 ring-forming carbon atoms which may be substituted or unsubstituted, or a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms which may be substituted or unsubstituted. p represents the average number of constitutional units. When p is 2 or more, two or more Vs １０１ may be the same as or different from each other.) (In formula (A2), １１１ R and １１５ R are each independently a hydrogen atom or a methyl group. １１２ R is an alkylene group having 1 to 20 carbon atoms. １１３ R and １１４ R are each independently an alkylene group having 1 to 30 carbon atoms. n １１２ represents an integer of 0 or 1. n １１３ represents an integer of 0 to 30.) (In formula (A3), １２１ R is an alkylene group having 1 to 6 carbon atoms. １２２ R is a hydrogen atom or a methyl group. n １２０ is 3 or 4. n １２１ represents an integer of 0 to 15. When n １２０ is 3, Z １２０ is a trivalent aliphatic hydrocarbon group having 3 to 10 carbon atoms which may be substituted or unsubstituted. When n １２０ is 4, Z １２０ is a tetravalent aliphatic hydrocarbon group having 5 to 10 carbon atoms which may be substituted or unsubstituted.) 3. The method according to claim 1 or 2, wherein in the step of forming the resin portion, a part or all of the lead conductor is inserted into the mold into which the thermosetting composition is filled.

4. A tab lead manufactured by the method according to any one of claims 1 to 3.

5. A tab lead having a lead conductor with a first main surface and a second main surface opposite to the first main surface, and a resin portion covering the first main surface, the second main surface, and both side surfaces between both ends of the lead conductor while exposing both ends of the lead conductor, wherein the resin portion contains a thermosetting resin.

6. The resin part is composed of a cured product of a thermosetting composition, and the thermosetting composition contains (A) a di(meth)acrylate compound having a structural unit represented by the following formula (A1), or a compound represented by the following formula (A2) or (A3), and (B) a thermal polymerization initiator. The tab lid according to claim 5. (In formula (A1), V １０１ is a divalent aromatic hydrocarbon group having 6 to 12 ring-forming carbon atoms which may be substituted or unsubstituted, a divalent alicyclic hydrocarbon group having 5 to 12 ring-forming carbon atoms which may be substituted or unsubstituted, or a divalent aliphatic hydrocarbon group having 2 to 30 carbon atoms which may be substituted or unsubstituted. p represents the average number of constitutional units. When p is 2 or more, two or more Vs １０１ may be the same as or different from each other.) (In formula (A2), R １１１ and R １１５ are each independently a hydrogen atom or a methyl group. R １１２ is an alkylene group having 1 to 20 carbon atoms. R １１３ and R １１４ are each independently an alkylene group having 1 to 30 carbon atoms. n １１２ represents an integer of 0 or 1. n １１３ represents an integer of 0 to 30.) (In formula (A3), R １２１ is an alkylene group having 1 to 6 carbon atoms. R １２２ is a hydrogen atom or a methyl group. n １２０ is 3 or 4. n １２１ represents an integer of 0 to 15. When n １２０ is 3, Z １２０ is a trivalent aliphatic hydrocarbon group having 3 to 10 carbon atoms which may be substituted or unsubstituted. When n １２０ is 4, Z １２０ is a tetravalent aliphatic hydrocarbon group having 5 to 10 carbon atoms which may be substituted or unsubstituted.) 7. The tab lead according to any one of claims 4 to 6, wherein the composition of the resin portion is uniform throughout the resin portion.

8. An electrochemical device comprising the tab lead according to any one of claims 4 to 7.

9. A battery comprising the tab lead according to any one of claims 4 to 7.

10. A capacitor comprising the tab lead according to any one of claims 4 to 7.

Images