Electrode plate and battery

Abstract

This electrode plate (1000) is provided with a collector (100) having a substrate (101) and a coating layer (102) that coats the substrate (101), and an electrode layer (110) disposed on the collector (100), the coating layer (102) containing conductive carbon (103) and a first binder (104), and the electrode layer (110) containing a second binder (113), the second binder (113) contains a styrene-based elastomer in which the molar fraction of repeating units derived from styrene is 0.12 or more and the total nitrogen content is 120-400 ppm by mass (inclusive).

Description

Technical Field

[0001] The present disclosure relates to an electrode plate and a battery. Background Art

[0002] A current collector is an indispensable component in electrochemical devices such as batteries and capacitors. An electrode layer such as an active material layer is disposed on the current collector. The adhesion between the current collector and the electrode layer affects the performance of the electrochemical device. As a current collector capable of improving the adhesion, a current collector having a substrate and a coating layer is known.

[0003] In Patent Document 1, a current collector for an electrical storage device in which a coating layer is formed on one or both sides of a sheet-like metal substrate is described. The coating layer contains a powdery carbon material and a binder. The binder contains polyvinylidene fluoride (PVDF). The adhesion between the metal substrate and the active material layer is improved by the coating layer.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-190527 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] An object of the present disclosure is to provide an electrode plate that is suitable not only for improving the peel strength between an electrode layer and a current collector but also for improving the uniformity of the peel strength.

[0009] Means for Solving the Problems

[0010] The present disclosure provides an electrode plate including: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing a conductive carbon and a first binder, the electrode layer containing a second binder, the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.12 or more and a total nitrogen content of 120 mass ppm or more and 400 mass ppm or less.

[0011] Effects of the Invention

[0012] According to the present disclosure, it is possible to provide an electrode plate that is suitable not only for improving the peel strength between an electrode layer and a current collector but also for improving the uniformity of the peel strength. Brief Description of the Drawings

[0013] Figure 1 A cross-sectional view of the electrode plate according to Embodiment 1.

[0014] Figure 2 A cross-sectional view of the electrode plate according to the modified example.

[0015] Figure 3 This is a cross-sectional view of the battery according to Embodiment 2.

[0016] Figure 4 This is a cross-sectional view of the battery according to the modified example.

[0017] Figure 5A This is a graph obtained from the peel test of the electrode plate of Example 1.

[0018] Figure 5B This is a graph obtained from the peel test of the electrode plate of Comparative Example 3. Detailed Embodiments

[0019] (Insight underlying the present disclosure)

[0020] The improved current collector is a means for improving the adhesion between the electrode layer and the current collector. However, the adhesion between the electrode layer and the current collector is based on the interaction between the electrode layer and the current collector. The inventors of the present invention focused on this point and tried to improve the adhesion between the electrode layer and the current collector by improving the adhesive of the electrode layer, and finally came up with the technology of the present disclosure.

[0021] The adhesion between the electrode layer and the current collector can be quantified as the peel strength. The uniformity of the peel strength can be quantified by the coefficient of variation of the peel strength.

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments.

[0023] (Embodiment 1)

[0024] Figure 1 This is a cross-sectional view of the electrode plate 1000 according to Embodiment 1. The electrode plate 1000 includes a current collector 100 and an electrode layer 110. The current collector 100 has a substrate 101 and a coating layer 102. The coating layer 102 covers the substrate 101 and contacts the electrode layer 110. The coating layer 102 contains conductive carbon 103 and a first adhesive 104. The electrode layer 110 contains a second adhesive 113. The second adhesive 113 contains a styrene-based elastomer in which the molar fraction of the repeating unit derived from styrene is 0.12 or more, and the total nitrogen content is 120 mass ppm or more and 400 mass ppm or less.

[0025] According to the above configuration, in addition to improving the peel strength between the electrode layer 110 and the current collector 100, the uniformity of the peel strength can also be improved. Furthermore, the cycle characteristics of the battery including the electrode plate 1000 can be improved. The electrode plate 1000 can be used as an electrode plate for electrochemical devices such as non-aqueous electrolyte batteries, solid batteries, and capacitors. The electrode plate 1000 is particularly suitable for the electrode plate of all-solid-state secondary batteries.

[0026] The high uniformity of the peel strength between the electrode layer 110 and the current collector 100 means that the deviation in performance between the plurality of electrode plates 1000 is small. If such electrode plates 1000 are used, an electrochemical device with constant quality can be manufactured, and the yield can be increased accordingly.

[0027] In the electrode plate 1000, the reason for the increase in the peel strength and its uniformity is not necessarily clear, but it is presumed that the interaction between the aromatic ring contained in the styrene-based elastomer and the conductive carbon affects the peel strength and its uniformity. As this interaction, π-π interaction can be cited. The π-π interaction includes the formation of a π bond between the π electrons present on the surface of the conductive carbon and the π electrons of the aromatic ring of the styrene-based elastomer. In addition, in the current collector 101, when the coating layer 102 covers only a part of the main surface of the substrate 101, the electrode layer 110 can be in direct contact with the substrate 101. In this case, it is presumed that the interaction between the nitrogen-containing styrene-based elastomer and the substrate 101 also affects the peel strength and its uniformity. As this interaction, intermolecular interaction can be cited.

[0028] The nitrogen-containing styrene-based elastomer can be a styrene-based elastomer having a nitrogen-containing modifying group. According to such an elastomer, by adjusting the amount of the nitrogen-containing modifying group, the total nitrogen amount can be set within the above range.

[0029] The electrode layer 110 can contain a solid electrolyte 111, can contain an active material 112, or can contain both.

[0030] [Current collector]

[0031] The current collector 100 includes a substrate 101 and a coating layer 102.

[0032] The current collector 100 has, for example, a plate shape or a foil shape. The thickness of the current collector 100 can be 0.1 μm or more and 1 mm or less, can be 1 μm or more and 100 μm or less, or can be 10 μm or more and 50 μm or less. When the thickness of the current collector 100 is 0.1 μm or more, the strength of the current collector 100 is increased, so that breakage of the current collector 100 is suppressed. When the thickness of the current collector 100 is 1 mm or less, the energy density of the electrochemical device can be increased by lightening the current collector 100. That is, by appropriately adjusting the thickness of the current collector 100, an electrochemical device can be stably manufactured, and the energy density of the electrochemical device can be increased.

[0033] <Coating layer>

[0034] The coating layer 102 can entirely coat the main surface of the substrate 101, or can partially coat the main surface of the substrate 101. The "main surface" refers to the surface of the substrate 101 having the largest area. The coating layer 102 is located between the substrate 101 and the electrode layer 110 and is in contact with the substrate 101 and the electrode layer 110 respectively. The shape of the coating layer 102 can be dot-shaped, strip-shaped, etc.

[0035] As the conductive carbon 103 contained in the coating layer 102, graphite-based materials such as natural graphite and artificial graphite, carbon black-based materials such as acetylene black (AB) and ketjen black (KB), conductive fiber materials such as carbon fiber (CF), vapor-grown carbon fiber (VGCF (registered trademark)), carbon nanotubes (CNT), and nano-carbon materials such as graphene can be cited. As the conductive carbon, one conductive carbon selected from the above can be used alone, or two or more conductive carbons selected from the above can be used.

[0036] The first binder 104 contained in the coating layer 102 may include aromatic super engineering plastics. The so-called aromatic super engineering plastics refer to engineering plastics that contain aromatic rings in the main chain skeleton and can be continuously used at a temperature of 150 °C or higher. As the aromatic super engineering plastics, polybenzimidazole (PBI), polyimide (PI), polyether ketone ether ketone ketone (PEKEKK), polyamideimide (PAI), polyether ether ketone (PEEK), polyether ketone (PEK), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI), polysulfone (PSU), polyparaphenylene (PPP), polyarylate (PAR), etc. can be cited. As the first binder 104, a mixture containing two or more selected from the above can be used. Aromatic super engineering plastics exhibit high heat resistance. Therefore, when the aromatic super engineering plastics are included in the coating layer 102 as the first binder 104, even if the member including the current collector 100 is compressed at a high temperature, the coating layer 102 is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0037] The aromatic super engineering plastic can be polyimide (PI). Polyimide has a tendency to exhibit higher heat resistance. Therefore, even if the member including the current collector 100 is compressed at a high temperature, the coating layer 102 is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0038] The first binder 104 may include a supplementary binder other than the aromatic super engineering plastics. Or, the first binder 104 can be an aromatic super engineering plastic. In other words, the first binder 104 can only include aromatic super engineering plastics.

[0039] Examples of supplementary adhesives include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aromatic polyamide resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, methyl polyacrylate, ethyl polyacrylate, hexyl polyacrylate, polymethacrylic acid, polymethyl methacrylate (PMMA), ethyl polymethacrylate, hexyl polymethacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polycarbonate, polyethersulfone, polyether ketone, polyetherether ketone, polyphenylene sulfide, hexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, ethyl cellulose, etc. As a supplementary adhesive, a copolymer synthesized from two or more monomers selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, butadiene, isoprene, styrene, pentafluoropropylene, fluoromethyl vinyl ether, acrylate, acrylic acid, and hexadiene may also be used. As a supplementary adhesive, one selected from the above may be used alone, or a mixture containing two or more selected from the above may be used.

[0040] From the viewpoint of excellent adhesiveness, the supplementary adhesive may contain an elastomer. An elastomer refers to a polymer having rubber elasticity. The elastomer used as an adhesive may be a thermoplastic elastomer or a thermosetting elastomer. As the elastomer, in addition to the above-mentioned styrene-based elastomers, butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), hydrogenated isoprene rubber (HIR), hydrogenated butyl rubber (HIIR), hydrogenated nitrile rubber (HNBR), acrylate-butadiene rubber (ABR), etc. may be mentioned. A mixture containing two or more selected from the above may be used.

[0041] The content rate of the first adhesive 104 in the coating layer 102 is not particularly limited. For example, it is 20% by mass or more and 95% by mass or less, may also be 40% by mass or more and 90% by mass or less, or may also be 55% by mass or more and 85% by mass or less. When the content rate of the first adhesive 104 is 95% by mass or less, the conductivity of the coating layer 102 is improved, and thus high output of the electrochemical device can be achieved. When the content rate of the first adhesive 104 is 20% by mass or more, the peeling of the coating layer 102 is likely to be suppressed due to the sufficient presence of the first adhesive 104 and the like.

[0042] The coating layer 102 may contain a conductive material other than the conductive carbon 103. Examples of conductive materials other than conductive carbon include conductive fiber materials such as metal fibers, conductive powder materials such as carbon fluoride and aluminum, conductive whisker materials such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene.

[0043] The coating layer 102 may contain elements or components other than the conductive carbon 103 and the first binder 104. The other elements or components may be added to the coating layer 102 by contamination or the like. For example, an inevitable oxide film or the like may be formed on a part of the surface of the coating layer 102. That is, the coating layer 102 may contain inevitable oxides or the like.

[0044] The coating layer 102 can be produced, for example, by a method of sputtering the material of the coating layer 102 onto the surface of the substrate 101. The coating layer 102 can be produced by coating a solution or dispersion containing the material of the coating layer 102 on the surface of the substrate 101. The coating of the solution or dispersion can be carried out using a gravure coater, a slot die coater, or the like.

[0045] There is no particular limitation on the mass per unit area of the coating layer 102. For example, it can be 0.01 g / m 2 or more and 5 g / m 2 or less, and can also be 0.1 g / m 2 or more and 3 g / m 2 or less, and can also be 0.5 g / m 2 or more and 2 g / m 2 or less. When the mass per unit area is 0.01 g / m 2 or more, contact between the substrate 101 and the electrode layer 110 can be prevented, and thus corrosion of the substrate 101 can be suppressed. When the mass per unit area is 5 g / m 2 or less, the resistance of the coating layer 102 is reduced, and for an electrochemical device, operation at high output can be easily carried out.

[0046] There is no particular limitation on the thickness of the coating layer 102. For example, it can be 0.001 μm or more and 10 μm or less, can also be 0.01 μm or more and 5 μm or less, and can also be 0.1 μm or more and 3 μm or less. When the thickness of the coating layer 102 is 0.001 μm or more, contact between the substrate 101 and the electrode layer 110 can be prevented, and thus corrosion of the substrate 101 can be suppressed. When the thickness of the coating layer 102 is 10 μm or less, the resistance of the coating layer 102 is reduced, and for an electrochemical device, operation at high output can be easily carried out.

[0047] <Substrate>

[0048] The substrate 101 has, for example, a foil shape or a plate shape. As the material of the substrate 101, a metal or an alloy can be used. As the metal, aluminum, iron, nickel, copper, etc. can be cited. As the alloy, aluminum alloy, stainless steel (SUS), etc. can be cited. The substrate 101 may contain aluminum or an aluminum alloy.

[0049] The substrate 101 may contain aluminum as a main component. "The substrate 101 contains aluminum as a main component" means that the content rate of aluminum in the substrate 101 is 50 mass% or more. Aluminum is a lightweight metal with high electrical conductivity. Therefore, the electrode plate 1000 having the substrate 101 containing aluminum as a main component can improve the weight energy density of the electrochemical device. The substrate 101 containing aluminum as a main component may further contain elements other than aluminum. It should be noted that when the substrate 101 contains only aluminum, that is, when the content rate of aluminum in the substrate 101 is 100%, the strength of the substrate 101 sometimes decreases. Therefore, the substrate 101 may contain elements other than aluminum. The content rate of aluminum in the substrate 101 may be 99 mass% or less, or may be 90 mass% or less.

[0050] The substrate 101 may contain an aluminum alloy. The aluminum alloy is lightweight and has high strength. Therefore, the electrode plate 1000 having the substrate 101 containing an aluminum alloy can realize an electrochemical device having both high weight energy density and high durability. There is no particular limitation on the aluminum alloy, and for example, Al-Cu alloy, Al-Mn alloy, Al-Mn-Cu alloy, Al-Fe-Cu alloy, etc. can be cited.

[0051] As the material of the substrate 101, an Al-Mn alloy can be used. The Al-Mn alloy has high strength and excellent formability and corrosion resistance. Therefore, the electrode plate 1000 having the substrate 101 containing an Al-Mn alloy can improve the cycle characteristics of the battery.

[0052] There is no particular limitation on the thickness of the substrate 101. For example, it is 0.1 μm or more and 50 μm or less, or may be 1 μm or more and 30 μm or less. When the thickness of the substrate 101 is 0.1 μm or more, the strength of the substrate 101 is improved, and thus breakage of the substrate 101 is suppressed. When the thickness of the substrate 101 is 50 μm or less, the mass of the substrate 101 is reduced, and the mass energy density of the electrochemical device can be improved.

[0053] [Electrode layer]

[0054] The electrode layer 110 contains a second binder 113. The electrode layer 110 may further contain a solid electrolyte 111 and an active material 112. Hereinafter, the solid electrolyte 111, the active material 112, and the second binder 113 will be described in detail.

[0055] <Solid electrolyte>

[0056] The solid electrolyte 111 may contain a sulfide solid electrolyte. The sulfide solid electrolyte may contain lithium. By using a sulfide solid electrolyte having lithium as the solid electrolyte 111, a lithium secondary battery using the electrode plate 1000 containing the sulfide solid electrolyte can be manufactured.

[0057] The solid electrolyte 111 may include solid electrolytes other than sulfide solid electrolytes, such as oxide solid electrolytes, halide solid electrolytes, polymer solid electrolytes, and complex hydride solid electrolytes. Alternatively, the solid electrolyte 111 may be a sulfide solid electrolyte. In other words, the solid electrolyte 111 may include only sulfide solid electrolytes.

[0058] In the present disclosure, the so-called "oxide solid electrolyte" refers to a solid electrolyte containing oxygen. The oxide solid electrolyte may further include anions other than oxygen, such as anions other than sulfur and halogen elements.

[0059] In the present disclosure, the so-called "halide solid electrolyte" refers to a solid electrolyte containing halogen elements and not containing sulfur. In the present disclosure, the so-called solid electrolyte not containing sulfur refers to a solid electrolyte represented by a composition formula not containing sulfur elements. Therefore, a solid electrolyte with a very small amount of sulfur component, for example, a solid electrolyte with sulfur of 0.1% by mass or less, is included in the solid electrolyte not containing sulfur. The halide solid electrolyte may further include oxygen as an anion other than halogen elements.

[0060] As the sulfide solid electrolyte, for example, Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 etc. LiX, Li2O, MO q , Li p MO q etc. may be added thereto. The element X in "LiX" is at least one selected from F, Cl, Br, and I. The element M in "MO q " and "Li p MO q " is at least one selected from P, Si, Ge, B, Al, Ga, In, Fe, and Zn. The p and q in "MO q " and "Li p MO q " are each independently a natural number.

[0061] As the sulfide solid electrolyte, for example, a Li2S-P2S5-based glass-ceramic can be used. LiX, Li2O, MO q , Li p MO qetc., and two or more selected from LiCl, LiBr, and LiI can be added. Since the Li2S-P2S5-based glass-ceramic is a relatively soft material, an electrode plate 1000 containing the Li2S-P2S5-based glass-ceramic can be used to manufacture a battery with higher durability.

[0062] As the oxide solid electrolyte, for example, NASICON-type solid electrolytes represented by LiTi2(PO4)3 and its elemental substitution products, perovskite-type solid electrolytes of the (LaLi)TiO3 system, and Li 14 ZnGe4O 16 , Li4SiO4, LiGeO4, and their elemental substitution products, LISICON-type solid electrolytes represented by Li7La3Zr2O 12 , and their elemental substitution products, garnet-type solid electrolytes, Li3PO4 and its N substitution products, glasses and glass-ceramics based on Li-B-O compounds such as LiBO2 and Li3BO3, and added with Li2SO4, Li2CO3, etc.

[0063] The halide solid electrolyte contains, for example, Li, M1, and X. M1 is at least one selected from metal elements and metalloid elements other than Li. X is at least one selected from F, Cl, Br, and I. Since the halide solid electrolyte has high thermal stability, the safety of the battery can be improved. Furthermore, since the halide solid electrolyte does not contain sulfur, the generation of hydrogen sulfide gas can be controlled.

[0064] In the present disclosure, the "metalloid element" is B, Si, Ge, As, Sb, and Te.

[0065] In the present disclosure, the "metal element" is all the elements contained in Groups 1 to 12 of the periodic table except hydrogen, and all the elements contained in Groups 13 to 16 of the periodic table except B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se.

[0066] That is, in the present disclosure, the "metalloid element" and the "metal element" are a group of elements that can become cations when forming inorganic compounds with halogen elements.

[0067] For example, the halide solid electrolyte can be a material represented by the following compositional formula (1).

[0068] Li α M1 β X γ Formula (1)

[0069] In the above compositional formula (1), α, β, and γ are each independently a value greater than 0. γ can be 4, 6, etc.

[0070] According to the above constitution, the ionic conductivity of the halide solid electrolyte is improved. Therefore, the ionic conductivity of the electrode plate 1000 can be improved. When the electrode plate 1000 is used in a battery, the cycle characteristics of the battery can be further improved.

[0071] In the above compositional formula (1), the element M1 may include Y (=yttrium). That is, the halide solid electrolyte may include Y as a metal element.

[0072] The halide solid electrolyte containing Y can be represented by, for example, the following compositional formula (2).

[0073] Li a Me b Y c X6 Formula (2)

[0074] In formula (2), a, b, and c may satisfy a + mb + 3c = 6 and c > 0. The element Me is at least one selected from metal elements and metalloid elements other than Li and Y. m represents the valence of the element Me. It should be noted that when the element Me contains multiple elements, mb is the sum of the product of the composition ratio of each element and the valence of the element. For example, when Me contains element Me1 and element Me2, the composition ratio of element Me1 is b1, the valence of element Me1 is m1, the composition ratio of element Me2 is b2, and the valence of element Me2 is m2, mb is represented by m1b1 + m2b2. In the above compositional formula (2), the element X is at least one selected from F, Cl, Br, and I.

[0075] The element Me may be, for example, at least one selected from Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, Gd, and Nb.

[0076] As the halide solid electrolyte, for example, the following materials can be used. According to the following materials, the ionic conductivity of the solid electrolyte 111 is further improved, and the output characteristics of the battery can be further improved.

[0077] The halide solid electrolyte may be a material represented by the following compositional formula (A1).

[0078] Li 6-3d Y d X6 Formula (A1)

[0079] In the compositional formula (A1), the element X is at least one selected from Cl, Br, and I. In the compositional formula (A1), d satisfies 0 < d < 2.

[0080] The halide solid electrolyte may be a material represented by the following compositional formula (A2).

[0081] Li3YX6 formula (A2)

[0082] In the compositional formula (A2), element X is at least one selected from Cl, Br, and I.

[0083] The halide solid electrolyte can be a material represented by the following compositional formula (A3).

[0084] Li 3-3δ Y 1+δ Cl6 formula (A3)

[0085] In the compositional formula (A3), δ satisfies 0 < δ ≤ 0.15.

[0086] The halide solid electrolyte can be a material represented by the following compositional formula (A4).

[0087] Li 3-3δ Y 1+δ Br6 formula (A4)

[0088] In the compositional formula (A4), δ satisfies 0 < δ ≤ 0.25.

[0089] The halide solid electrolyte can be a material represented by the following compositional formula (A5).

[0090] Li 3-3δ+a Y 1+δ-a Me a Cl 6-x-y Br x I y Formula (A5)

[0091] In the compositional formula (A5), element Me is at least one selected from Mg, Ca, Sr, Ba, and Zn.

[0092] Furthermore, in the above compositional formula (A5), the following are satisfied:

[0093] -1 < δ < 2,

[0094] 0 < a < 3,

[0095] 0 < (3 - 3δ + a),

[0096] 0 < (1 + δ - a),

[0097] 0 ≤ x ≤ 6,

[0098] 0 ≤ y ≤ 6, and

[0099] (x + y) ≤ 6.

[0100] The halide solid electrolyte can be a material represented by the following compositional formula (A6).

[0101] Li 3-3δY 1+δ-a Me a Cl 6-x-y Br x I y Formula (A6)

[0102] In the composition formula (A6), the element Me is at least one selected from Al, Sc, Ga, and Bi.

[0103] Furthermore, in the above composition formula (A6), the following conditions are satisfied:

[0104] -1 < δ < 1,

[0105] 0 < a < 2,

[0106] 0 < (1 + δ - a),

[0107] 0 ≤ x ≤ 6,

[0108] 0 ≤ y ≤ 6, and

[0109] (x + y) ≤ 6.

[0110] The halide solid electrolyte can be a material represented by the following composition formula (A7).

[0111] Li 3-3δ-a Y 1+δ-a Me a Cl 6-x-y Br x I y Formula (A7)

[0112] In the above composition formula (A7), the element Me is at least one selected from Zr, Hf, and Ti.

[0113] Furthermore, in the above composition formula (A7), the following conditions are satisfied:

[0114] -1 < δ < 1,

[0115] 0 < a < 1.5,

[0116] 0 < (3 - 3δ - a),

[0117] 0 < (1 + δ - a),

[0118] 0 ≤ x ≤ 6,

[0119] 0 ≤ y ≤ 6, and

[0120] (x + y) ≤ 6.

[0121] The halide solid electrolyte can be a material represented by the following composition formula (A8).

[0122] Li 3-3δ-2a Y1+δ-a Me a Cl 6-x-y Br x I y Formula (A8)

[0123] In the compositional formula (A8), the element Me is at least one selected from Ta and Nb.

[0124] Furthermore, in the above compositional formula (A8), the following are satisfied:

[0125] -1 < δ < 1,

[0126] 0 < a < 1.2,

[0127] 0 < (3 - 3δ - 2a),

[0128] 0 < (1 + δ - a),

[0129] 0 ≤ x ≤ 6,

[0130] 0 ≤ y ≤ 6, and

[0131] (x + y) ≤ 6.

[0132] The halide solid electrolyte may be a compound containing Li, M2, O (oxygen), and X2. The element M2 includes, for example, at least one selected from Nb and Ta. In addition, X2 is at least one selected from F, Cl, Br, and I.

[0133] The compound containing Li, M2, X2, and O (oxygen) may be represented, for example, by the compositional formula: Li x M2O y X2 5+x-2y wherein x may satisfy 0.1 < x < 7.0. y may satisfy 0.4 < y < 1.9.

[0134] As the halide solid electrolyte, more specifically, for example, Li3Y(Cl, Br, I)6, Li 2.7 Y 1.1 (Cl, Br, I)6, Li2Mg(F, Cl, Br, I)4, Li2Fe(F, Cl, Br, I)4, Li(Al, Ga, In)(F, Cl, Br, I)4, Li3(Al, Ga, In)(F, Cl, Br, I)6, Li3(Ca, Y, Gd)(Cl, Br, I)6, Li 2.7 (Ti, Al)F6, Li 2.5(Ti, Al)F6, Li(Ta, Nb)O(F, Cl)4, etc. It should be noted that in this disclosure, when an element in a formula is represented as "(Al, Ga, In)", this notation means at least one element selected from the group of elements within the parentheses. That is, "(Al, Ga, In)" is synonymous with "at least one selected from Al, Ga, and In". The same applies to other elements.

[0135] As a polymer solid electrolyte, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound can have an ethylene oxide structure. The polymer compound having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further improved. As the lithium salt, LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), LiC(SO2CF3)3, etc. can be used. The lithium salt can be used alone or two or more can be used in combination.

[0136] As a complex hydride solid electrolyte, for example, LiBH4 - LiI, LiBH4 - P2S5, etc. can be used.

[0137] The shape of the solid electrolyte 111 is not particularly limited and can be needle-shaped, spherical, ellipsoidal, etc. The shape of the solid electrolyte 111 can be particulate.

[0138] When the shape of the solid electrolyte 111 is particulate (e.g., spherical), the median diameter of the solid electrolyte 111 can be 0.1 μm or more and 5 μm or less, or can be 0.5 μm or more and 3 μm or less. When the median diameter of the solid electrolyte 111 is 0.1 μm or more, the dispersibility of the electrode composition (slurry) for manufacturing the electrode plate 1000 is improved, and a denser structure can be obtained. When the median diameter of the solid electrolyte 111 is 5 μm or less, the electrode plate 1000 has high surface smoothness and can have a denser structure.

[0139] The so-called median diameter refers to the particle diameter at which the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is obtained by the laser diffraction scattering method. The same applies to other materials below.

[0140] The specific surface area of the solid electrolyte 111 can be 0.1 m 2 / g or more and 100 m 2 / g or less, or can be 1 m 2 / g or more and 10 m 2 / g or less. When the specific surface area of the solid electrolyte 111 is 0.1 m 2above / g and 100 m 2 When it is below / g, the dispersibility of the electrode composition (slurry) for manufacturing the electrode plate 1000 is improved, and a denser structure can be obtained. The specific surface area can be measured by the BET multipoint method using a gas adsorption amount measuring device.

[0141] The ionic conductivity of the solid electrolyte 111 can be 0.01 mS / cm 2 or more, and can also be 0.1 mS / cm 2 or more, and can also be 1 mS / cm 2 or more. When the ionic conductivity of the solid electrolyte 111 is 0.01 mS / cm 2 or more, the output characteristics of the battery can be improved.

[0142] <Active material>

[0143] The active material 112 contains a material having the property of storing and releasing metal ions (such as lithium ions). The active material 112 includes, for example, a positive electrode active material or a negative electrode active material. When the electrode plate 1000 contains the active material 112, a lithium secondary battery can be manufactured using the electrode plate 1000.

[0144] The active material 112 includes, for example, a material having the property of storing and releasing metal ions (such as lithium ions) as a positive electrode active material. Examples of the positive electrode active material include transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, and their lithium-containing compounds. Examples of the lithium-containing transition metal oxides include Li(NiCoAl)O2, Li(NiCoMn)O2, LiCoO2, etc. When using a lithium-containing transition metal oxide as the positive electrode active material, for example, the manufacturing cost of the electrode plate 1000 can be reduced, and the average discharge voltage of the battery can be increased. Li(NiCoAl)O2 means containing Ni, Co, and Al in an arbitrary ratio. Li(NiCoMn)O2 means containing Ni, Co, and Mn in an arbitrary ratio.

[0145] The median diameter of the positive electrode active material can be 0.1 μm or more and 100 μm or less, and can also be 1 μm or more and 10 μm or less. When the median diameter of the positive electrode active material is 0.1 μm or more, in the electrode plate 1000, the active material 112 and the solid electrolyte 111 can be well dispersed. As a result, the charge-discharge characteristics of the battery are improved. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate in the positive electrode active material is increased. Therefore, the battery can operate at a high output.

[0146] The active material 112 contains, for example, a material having the property of storing and releasing metal ions (such as lithium ions) as the negative electrode active material. Examples of the negative electrode active material include metal materials, carbon materials, oxides, nitrides, tin compounds, and silicon compounds. The metal material may be a single metal or an alloy. Examples of the metal material include lithium metal and lithium alloys. Examples of the carbon material include natural graphite, coke, carbon in the middle of graphitization, carbon fiber, spherical carbon, artificial graphite, and amorphous carbon. By using silicon (Si), tin (Sn), silicon compounds, tin compounds, etc., the capacity density of the battery can be improved. By using an oxide compound containing titanium (Ti) or niobium (Nb), the safety of the battery can be improved.

[0147] The median diameter of the negative electrode active material may be 0.1 μm or more and 100 μm or less, or may be 1 μm or more and 10 μm or less. When the median diameter of the negative electrode active material is 0.1 μm or more, the active material 112 and the solid electrolyte 111 can be well dispersed in the electrode plate 1000. Thereby, the charge-discharge characteristics of the battery are improved. When the median diameter of the negative electrode active material is 100 μm or less, the lithium diffusion rate in the negative electrode active material is increased. Therefore, the battery can operate at a high output.

[0148] In order to reduce the interfacial resistance between each active material and the solid electrolyte, the positive electrode active material and the negative electrode active material can be coated with a coating material. That is, a coating layer can be provided on the surfaces of the positive electrode active material and the negative electrode active material. The coating layer is a layer containing the coating material. As the coating material for the coating layer, a material with low electronic conductivity can be used. As the coating material for the coating layer, an oxide material, an oxide solid electrolyte, a halide solid electrolyte, a sulfide solid electrolyte, etc. can be used. The positive electrode active material and the negative electrode active material can be coated with only one of the above-mentioned materials as the coating material. That is, for the coating layer, a coating layer formed of only one of the above-mentioned materials can be provided. Alternatively, two or more of the above-mentioned materials can be used to provide a coating layer with two or more layers.

[0149] Examples of the oxide material as the coating material for the coating layer include SiO2, Al2O3, TiO2, B2O3, Nb2O5, WO3, ZrO2, etc.

[0150] As the oxide solid electrolyte as the coating material for the coating layer, the previously exemplified oxide solid electrolytes can be used. For example, Li-Nb-O compounds such as LiNbO3, Li-B-O compounds such as LiBO2 and Li3BO3, Li-Al-O compounds such as LiAlO2, Li-Si-O compounds such as Li4SiO4, Li-S-O compounds such as Li2SO4, Li4Ti5O12 Li-Ti-O compounds such as etc., Li-Zr-O compounds such as Li2ZrO3, Li-Mo-O compounds such as Li2MoO3, Li-V-O compounds such as LiV2O5, Li-W-O compounds such as Li2WO4, Li-P-O compounds such as LiPO4, etc. The oxide solid electrolyte has high potential stability. Therefore, by using the oxide solid electrolyte as the coating material, the cycle characteristics of the battery can be further improved.

[0151] As the halide solid electrolyte used as the coating material for the coating layer, the previously exemplified halide solid electrolytes can be used. For example, Li-Y-Cl compounds such as LiYCl6, Li-Y-Br-Cl compounds such as LiYBr2Cl4, Li-Ta-O-Cl compounds such as LiTaOCl4, Li 2.7 Ti 0.3 Al 0.7 F6 and other Li-Ti-Al-F compounds, etc. The halide solid electrolyte has high ionic conductivity and high potential stability. Therefore, by using the halide solid electrolyte as the coating material, the cycle characteristics of the battery can be further improved.

[0152] As the sulfide solid electrolyte used as the coating material for the coating layer, the previously exemplified sulfide solid electrolytes can be used. For example, Li-P-S compounds such as Li2S-P2S5, etc. The sulfide solid electrolyte has high ionic conductivity and low Young's modulus. Therefore, by using the sulfide solid electrolyte as the coating material, uniform coating can be achieved and the cycle characteristics of the battery can be further improved.

[0153] <Second binder>

[0154] As described above, the second binder 113 contains a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 mass ppm or more and 400 mass ppm or less. With such a configuration, a sufficient amount of aromatic rings are present in the electrode layer 110, and the interaction between the conductive carbon 103 and the second binder 113 is more strongly exerted. Therefore, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase. Further, in the current collector 101, when the coating layer 102 covers only a part of the substrate 101, the electrode layer 110 can be in direct contact with the substrate 101. In this case, a modified group containing an appropriate amount of nitrogen is present in the electrode layer 110, and the interaction with the substrate 101 is strongly exerted over a wider range. Therefore, there is a tendency that the peel strength between the electrode layer 110 and the current collector 100 increases and the uniformity of the strength improves. The styrene-based elastomer refers to an elastomer containing repeating units derived from styrene. The repeating unit refers to the molecular structure derived from a monomer and is sometimes also referred to as a structural unit. Since the styrene-based elastomer is excellent in flexibility and elasticity, it is suitable as an adhesive for the electrode plate 1000.

[0155] In the styrene-based elastomer, the ratio of the degree of polymerization m of the repeating units derived from styrene to the degree of polymerization n of the repeating units derived from monomers other than styrene is defined as m:n. In this case, in the styrene-based elastomer, the molar fraction (φ) of the repeating units derived from styrene can be calculated by φ = m / (m + n). In the styrene-based elastomer, the molar fraction (φ) of the repeating units derived from styrene can be determined, for example, by measurement using proton nuclear magnetic resonance ( 1 1H-NMR).

[0156] In the styrene-based elastomer, the molar fraction (φ) of the repeating units derived from styrene is 0.12 or more. Thereby, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase. The molar fraction (φ) of the styrene-based elastomer may be 0.12 or more and 0.55 or less, or may be 0.18 or more and 0.3 or less. By the molar fraction (φ) of the styrene-based elastomer being 0.12 or more, the strength of the electrode layer 110 can be increased. By φ of the styrene-based elastomer being 0.55 or less, the flexibility of the electrode layer 110 can be increased.

[0157] The content rate of the repeating unit derived from styrene in the styrene-based elastomer may be 20% by mass or more. Thereby, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase. The content rate of the repeating unit derived from styrene in the styrene-based elastomer may be 20% by mass or more and 70% by mass or less, and may also be 30% by mass or more and 45% by mass or less. The content rate of the repeating unit derived from styrene in the styrene-based elastomer can be calculated using the mole fraction of each repeating unit contained in the styrene-based elastomer and the molecular weight of each repeating unit that can be obtained by the above method. Or it can be measured by a method using an ultraviolet spectrophotometer.

[0158] The styrene-based elastomer may be a block copolymer including a first block composed of a repeating unit derived from styrene and a second block composed of a repeating unit derived from a conjugated diene. Examples of the conjugated diene include butadiene and isoprene. The repeating unit derived from the conjugated diene may be hydrogenated. That is, the repeating unit derived from the conjugated diene may have an unsaturated bond such as a carbon-carbon double bond, or may not have an unsaturated bond such as a carbon-carbon double bond. The block copolymer may have an arrangement of a triblock composed of two first blocks and one second block. The block copolymer may be an ABA-type triblock copolymer. In this triblock copolymer, the A block corresponds to the first block, and the B block corresponds to the second block. The first block functions as a hard segment, for example. The second block functions as a soft segment, for example.

[0159] Examples of the styrene-based elastomer include styrene-ethylene / butene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene rubber (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-butadiene rubber (HSBR), etc. The second adhesive 113 may contain SBR or SEBS as the styrene-based elastomer. As the second adhesive 113, a mixture containing two or more selected from the above may be used. Since the styrene-based elastomer has excellent flexibility and elasticity, it is suitable as an adhesive for the electrode layer 110.

[0160] The styrenic elastomer may be a styrenic triblock copolymer. Examples of the styrenic triblock copolymer include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and the like. These styrenic triblock copolymers are sometimes referred to as styrenic thermoplastic elastomers. These styrenic triblock copolymers tend to be soft and have high strength.

[0161] The styrenic elastomer may contain a styrene-ethylene / butylene-styrene block copolymer (SEBS). Since SEBS has excellent flexibility and elasticity and excellent filling properties during hot compression, it is particularly suitable as an adhesive for the electrode layer 110.

[0162] The total nitrogen content of the styrenic elastomer is 120 mass ppm or more and 400 mass ppm or less. Thus, there is a tendency that the peel strength between the electrode layer 110 and the current collector 100 is increased and its uniformity is improved. The total nitrogen content of the styrenic elastomer may be 150 mass ppm or more and 300 mass ppm or less, or may be 190 mass ppm or more and 250 mass ppm or less. The total nitrogen content can be determined using a trace total nitrogen analyzer. For example, using a trace total nitrogen analyzer (TN-2100H) manufactured by Nitto Seiko Analysis Co., Ltd., and using a pyridine / toluene solution as a standard sample, the mass (μg) of nitrogen (N) contained in 1 g of the polymer is measured. The total nitrogen content is the ratio (μg / g = ppm) of the mass (μg) of nitrogen (N) contained in 1 g of the polymer.

[0163] Styrene-based elastomers may contain a modifying group having a nitrogen atom. The so-called modifying group refers to a functional group that chemically modifies all of the repeating units contained in the polymer chain, a part of the repeating units contained in the polymer chain, or the terminal portion of the polymer chain. The modifying group can be introduced into the polymer chain through substitution reactions, addition reactions, etc. The so-called modifying group having a nitrogen atom is a nitrogen-containing functional group, and examples include an amino group, a nitrile group, a nitro group, etc. The modifying group having a nitrogen atom can be introduced into the polymer chain, for example, by reacting a modifier. Examples of the compound as the modifier include amine compounds, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing a nitrogen group, vinyl compounds containing a nitrogen group, epoxy compounds containing a nitrogen group, alkoxysilane compounds containing a nitrogen group, etc. The position of the modifying group can be the terminal of the polymer chain. The styrene-based elastomer having a modifying group at the terminal of the polymer chain can have an effect similar to that of a so-called surfactant. That is, by using a styrene-based elastomer having a modifying group at the terminal of the polymer chain, the modifying group adsorbs to the solid electrolyte 111, and the polymer chain can inhibit the aggregation between the particles of the solid electrolyte 111. As a result, the dispersibility of the solid electrolyte 111 can be further improved. The styrene-based elastomer can be, for example, a terminal amine-modified styrene-based elastomer. The styrene-based elastomer can be, for example, a styrene-based elastomer having a nitrogen atom at at least one terminal of the polymer chain and having a star polymer structure centered on a nitrogen-containing alkoxysilane substituent.

[0164] In addition to having a modifying group containing a nitrogen atom, the styrene-based elastomer may further have a modifying group generated by an atom other than nitrogen. The modifying group generated by an atom other than nitrogen contains, for example, elements such as O, S, F, Cl, Br, F having a relatively high electronegativity, and Si, Sn, P having a relatively low electronegativity. By using a modifying group containing such elements, polarity can be imparted to the styrene-based elastomer. Examples of the modifying group include a carboxyl group, an acid anhydride group, an acyl group, a hydroxyl group, a sulfo group, a thioalkyl group, a phosphoric acid group, a phosphonic acid group, an isocyanate group, an epoxy group, a silyl group, etc. A specific example of the acid anhydride group is a maleic anhydride group. The modifying group can be a functional group that can be introduced by reacting a modifier generated from the following compounds. Examples of the compound as the modifier include epoxy compounds, ether compounds, ester compounds, mercapto derivatives, thiocarbonyl compounds, silicon halide compounds, epoxy silicon compounds, vinylated silicon compounds, alkoxysilane compounds, tin halide compounds, organotin carboxylate compounds, phosphite compounds, phosphine compounds, etc. When the styrene-based elastomer contains the above-mentioned modifying group, the peel strength between the electrode layer 110 and the current collector 100 can be improved through the interaction with the current collector 100.

[0165] For the purpose of adjusting the total nitrogen content, the styrene-based elastomer may be a mixture of two or more styrene-based elastomers having different total nitrogen contents. A styrene-based elastomer having a relatively high total nitrogen content may be mixed with an unmodified styrene-based elastomer.

[0166] The weight average molecular weight (M w ) of the styrene-based elastomer may be 200,000 or more. The weight average molecular weight of the styrene-based elastomer may be 300,000 or more, may be 500,000 or more, may be 800,000 or more, or may be 1,000,000 or more. The upper limit value of the weight average molecular weight is, for example, 1,500,000. By the weight average molecular weight of the styrene-based elastomer being 200,000 or more, the particles of the solid electrolyte 111 and the active material 112 can be bonded with sufficient bonding strength. By the weight average molecular weight of the styrene-based elastomer being 1,500,000 or less, the ion conduction between the particles of the solid electrolyte 111 is not easily hindered by the second binder 113, and the output characteristics of the battery can be improved. The weight average molecular weight of the styrene-based elastomer can be determined, for example, by gel permeation chromatography (GPC) measurement using polystyrene as a standard sample. In other words, the weight average molecular weight is a value converted using polystyrene. In the GPC measurement, chloroform can be used as an eluent. When two or more peaks are observed in the graph obtained by the GPC measurement, the weight average molecular weight calculated from the entire peak range including each peak can be regarded as the weight average molecular weight of the styrene-based elastomer.

[0167] The second binder 113 may contain a binder other than the styrene-based elastomer. Alternatively, the second binder 113 may be a styrene-based elastomer. In other words, the second binder 113 may contain only the styrene-based elastomer.

[0168] <Electrode layer>

[0169] The electrode layer 110 contains the second binder 113. The electrode layer 110 may further contain the solid electrolyte 111, may contain the active material 112, or may contain both. According to this configuration, while maintaining sufficient strength of the electrode layer 110, the ionic conductivity inside the electrode layer 110 is improved, and the battery can operate with high output.

[0170] The median diameter of the solid electrolyte 111 contained in the electrode layer 110 may be smaller than the median diameter of the active material 112. Thereby, the solid electrolyte 111 and the active material 112 can be well dispersed.

[0171] In the electrode layer 110, for the volume ratio "v1:100 - v1" of the active material 112 to the solid electrolyte 111, 30 ≤ v1 ≤ 95 can be satisfied. v1 represents the volume ratio of the active material 112 when the total volume of the active material 112 and the solid electrolyte 111 contained in the electrode layer 110 is set to 100. When 30 ≤ v1 is satisfied, it is easy to ensure sufficient energy density for the battery. When v1 ≤ 95 is satisfied, the battery can operate more easily under high output.

[0172] The thickness of the electrode layer 110 can be 10 μm or more and 500 μm or less. When the thickness of the electrode layer 110 is 10 μm or more, it is easy to ensure sufficient energy density for the battery. When the thickness of the electrode layer 110 is 500 μm or less, the battery can operate more easily under high output.

[0173] In the electrode layer 110, the ratio of the second binder 113 to the solid electrolyte 111 can be 0.1 mass% or more and 10 mass% or less, can also be 0.5 mass% or more and 8 mass% or less, and can also be 1 mass% or more and 5 mass% or less. When the ratio of the second binder 113 to the solid electrolyte 111 is 0.1 mass% or more, there is a tendency to bond more particles of the solid electrolyte 111 using the second binder 113. Thus, the film strength of the electrode layer 110 can be improved. When the ratio of the second binder 113 to the solid electrolyte 111 is 10 mass% or less, in the electrode layer 110, there is a tendency to improve the contact between the particles of the solid electrolyte 111. Thus, the ionic conductivity of the electrode layer 110 can be improved.

[0174] In the electrode layer 110, the ratio of the second binder 113 to the active material 112 can be 0.03 mass% or more and 4 mass% or less, can also be 0.15 mass% or more and 2 mass% or less, and can also be 0.3 mass% or more and 1 mass% or less. When the ratio of the second binder 113 to the active material 112 is 0.03 mass% or more, there is a tendency to bond more particles of the active material 112 using the second binder 113. Thus, the film strength of the electrode layer 110 can be improved. When the ratio of the second binder 113 to the active material 112 is 4 mass% or less, in the electrode layer 110, there is a tendency to improve the contact between the particles of the active material 112. Thus, the output characteristics of the battery can be improved.

[0175] For the purpose of improving electronic conductivity, the electrode layer 110 may further contain a conductive aid. As the conductive aid, for example, graphite-based materials such as natural graphite and artificial graphite, carbon black-based materials such as acetylene black and Ketjen black, conductive fiber-based materials such as carbon fiber and metal fiber, conductive powder-based materials such as carbon fluoride and aluminum, conductive whisker-based materials such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene can be cited. If a carbon material is used as the conductive aid, cost reduction can be achieved.

[0176] For the purpose of improving the dispersibility of the solid electrolyte 111 and the active material 112, the electrode layer 110 may contain a dispersant. The dispersant can be a low-molecular dispersant or a high-molecular dispersant. As the dispersant, for example, commercially available dispersants, wetting agents, or surfactants can be used.

[0177] In the electrode layer 110, the dispersant may contain an amine compound. The amine compound is suitable for improving the dispersibility of the solid electrolyte 111. As the amine compound, for example, aliphatic amines such as methylamine and dimethylamine, aromatic amines such as aniline, and heterocyclic amines such as imidazole and imidazoline can be cited.

[0178] In the electrode layer 110, the dispersant may contain imidazoline or an imidazoline derivative. Imidazoline or an imidazoline derivative is more suitable for improving the dispersibility of the solid electrolyte 111. As the imidazoline derivative, for example, 1-hydroxyethyl-2-vinylimidazoline can be cited.

[0179] In the electrode layer 110, the ratio of the mass of the dispersant to the mass of the solid electrolyte 111 is not particularly limited. For example, it is 0.001 mass% or more and 10 mass% or less, and it can also be 0.01 mass% or more and 1.0 mass% or less. When the ratio of the mass of the dispersant is 0.001 mass% or more, the dispersibility of the solid electrolyte 111 can be improved in the electrode layer 110. When the ratio of the mass of the dispersant is 10 mass% or less, a decrease in the ionic conductivity of the solid electrolyte 111 can be suppressed.

[0180] [Manufacturing method of the electrode plate]

[0181] The electrode plate 1000 can be manufactured, for example, by the following method. First, an electrode composition containing a solid electrolyte 111, an active material 112, and a second binder 113 for forming the electrode layer 110 is prepared. As the electrode composition, a slurry in which the solid electrolyte 111, the active material 112, and the second binder 113 are dispersed in a solvent can be used. As the solvent, a solvent that does not react with the solid electrolyte 111, such as an aromatic hydrocarbon solvent like tetralin, can be used. Next, the electrode composition is coated on the coating layer 102 of the current collector 100. As methods for coating the electrode composition, an extrusion die coating method, a gravure coating method, a doctor blade method, a rod coating method, a spraying method, an electrostatic coating method, etc. can be cited. By drying the obtained coating film, the electrode layer 110 is formed, and the electrode plate 1000 can be obtained. There is no particular limitation on the drying method of the coating film. For example, the coating film can be dried by heating it at a set temperature of 80°C or higher and 150°C or lower using warm air / hot air drying. It should be noted that the method of coating the electrode composition on the coating layer 102 to form the electrode layer 110 is sometimes referred to as a wet coating method.

[0182] [Method for Measuring Peel Strength of Electrode Plate]

[0183] The peel strength between the electrode layer 110 and the current collector 100 can be measured by the following method in a drying chamber with a dew point of -50°C or lower, using a universal material testing machine (manufactured by A&D Company, RTH-1310). First, the electrode plate 1000 cut to a width of 15 mm is bonded to a double-sided tape for test plate. Specifically, the electrode layer 110 of the electrode plate 1000 is adhered to the test plate via the double-sided tape. Next, using a testing machine equipped with a jig for a 90° peel test of the tape, the electrode layer 110 is peeled from the current collector 100 at a peel angle of 90° and a peel speed of 5 mm / min. Then, after the measurement starts, the measured values for the length from the initial 10 mm to 12 mm peeled from the current collector 100 are not used, and then, for the electrode layer 110 with a length of 5 mm peeled from the current collector 100, the continuously recorded measured values (unit:

[0184] N) are recorded. The average value (Av) of the values obtained by dividing the measured values by the width of the electrode plate 1000 can be regarded as the peel strength between the electrode layer 110 and the current collector 100 in the electrode plate 1000 (unit: N / m). In addition, the standard deviation (σ) of the values obtained by dividing the measured values by the width of the electrode plate 1000 is calculated, and the value obtained by dividing the standard deviation (σ) by the average value (Av) can be regarded as the coefficient of variation. Among them, the coefficient of variation represents the deviation of the peel strength. The lower the coefficient of variation, the higher the uniformity of the peel strength.

[0185] Figure 2A cross-sectional view of the electrode plate 1100 according to the modified example. The electrode plate 1100 includes a current collector 100a and an electrode layer 110. The current collector 100a has a substrate 101 and a coating layer 102a. The coating layer 102a is strip-shaped in plan view and covers only a part of the main surface of the substrate 101. Except for the shape of the coating layer 102a, the configuration of the electrode plate 1100 is the same as that of the electrode plate 1000 described previously. The electrode plate 1100 can be used instead of the electrode plate 1000.

[0186] (Embodiment 2)

[0187] Figure 3 A cross-sectional view of the battery 2000 according to Embodiment 2. The battery 2000 includes a negative electrode 201, a positive electrode 203, and an electrolyte layer 202.

[0188] At least one selected from the negative electrode 201 and the positive electrode 203 includes the electrode plate 1000 in Embodiment 1. That is, at least one selected from the negative electrode 201 and the positive electrode 203 includes an electrode layer 110 and a current collector 100.

[0189] The electrolyte layer 202 is located between the negative electrode 201 and the positive electrode 203.

[0190] Since the peeling strength between the electrode layer 110 and the current collector 100 is high and the uniformity of the peeling strength is also high, the battery 2000 using the electrode plate 1000 having such an electrode layer 110 and current collector 100 has excellent cycle characteristics. In addition, the output characteristics of the battery 2000 can also be improved.

[0191] As Figure 3 shown, in the battery 2000, the negative electrode 201 can be the electrode plate 1000 in Embodiment 1. In this case, the negative electrode 201 includes the electrode layer 110 and the current collector 100 described in Embodiment 1. Hereinafter, the battery 2000 in which the negative electrode 201 is the electrode plate 1000 will be described. However, the battery 2000 is not limited to the following manner. In the battery 2000, the positive electrode 203 can be the electrode plate 1000 in the above-described Embodiment 1.

[0192] According to the above configuration, the output characteristics of the battery 2000 can be further improved.

[0193] The electrolyte layer 202 is a layer containing an electrolyte material. As the electrolyte material, for example, a solid electrolyte can be cited. That is, the electrolyte layer 202 can be a solid electrolyte layer. As the solid electrolyte contained in the electrolyte layer 202, the solid electrolytes exemplified as the solid electrolyte 111 can be used. For example, a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte, a polymer solid electrolyte, a complex hydride solid electrolyte, etc. can be used.

[0194] The electrolyte layer 202 may contain a solid electrolyte as a main component. The electrolyte layer 202 may contain a solid electrolyte in a mass ratio of 70% or more (70 mass% or more) with respect to the whole of the electrolyte layer 202.

[0195] According to the above configuration, the charge and discharge characteristics of the battery 2000 can be improved.

[0196] The electrolyte layer 202 may contain a solid electrolyte as a main component, and may further contain inevitable impurities, or starting materials, by-products, decomposition products, etc. used in synthesizing the solid electrolyte.

[0197] Except for inevitably mixed-in impurities, the electrolyte layer 202 may contain a solid electrolyte in a mass ratio of 100% (100 mass%) with respect to the whole of the electrolyte layer 202.

[0198] According to the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0199] The electrolyte layer 202 may contain two or more of the materials listed as solid electrolytes. For example, the electrolyte layer 202 may contain a halide solid electrolyte and a sulfide solid electrolyte.

[0200] The thickness of the electrolyte layer 202 may be 1 μm or more and 300 μm or less. When the thickness of the electrolyte layer 202 is 1 μm or more, the possibility of short circuit between the negative electrode 201 and the positive electrode 203 is reduced. When the thickness of the electrolyte layer 202 is 300 μm or less, the battery 2000 can easily operate at high output. That is, if the thickness of the electrolyte layer 202 is appropriately adjusted, the safety of the battery 2000 can be sufficiently ensured, and the battery 2000 can operate at high output.

[0201] There is no particular limitation on the shape of the solid electrolyte contained in the battery 2000. The shape of the solid electrolyte may be needle-like, spherical, ellipsoidal, etc. The shape of the solid electrolyte may be particulate.

[0202] The positive electrode 203 may contain an electrolyte material, for example, may contain a solid electrolyte. As the solid electrolyte, the solid electrolytes exemplified as the materials constituting the electrolyte layer 202 can be used. According to the above configuration, the ionic conductivity (for example, lithium ion conductivity) inside the positive electrode 203 is improved, and the battery 2000 can operate at high output.

[0203] The positive electrode 203 contains, for example, a material having the property of storing and releasing metal ions (for example, lithium ions) as a positive electrode active material. As the positive electrode active material, the materials exemplified in the above-described Embodiment 1 can be used.

[0204] The median diameter of the positive electrode active material may be 0.1 μm or more and 100 μm or less. When the median diameter of the positive electrode active material is 0.1 μm or more, in the positive electrode 203, the positive electrode active material and the solid electrolyte can be well dispersed. Thereby, the charge-discharge characteristics of the battery 2000 are improved. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate in the positive electrode active material is increased. Therefore, the battery 2000 can operate at a high output.

[0205] The median diameter of the positive electrode active material may be larger than the median diameter of the solid electrolyte. Thereby, the solid electrolyte and the positive electrode active material can be well dispersed.

[0206] In the positive electrode 203, for the volume ratio “v2: 100 - v2” of the positive electrode active material and the solid electrolyte, 30 ≤ v2 ≤ 95 can be satisfied. v2 represents the volume ratio of the positive electrode active material when the total volume of the positive electrode active material and the solid electrolyte contained in the positive electrode 203 is set to 100. When 30 ≤ v2 is satisfied, it is easy to ensure a sufficient energy density for the battery 2000. When v2 ≤ 95 is satisfied, it is easier for the battery 2000 to operate at a high output.

[0207] The thickness of the positive electrode 203 may be 10 μm or more and 500 μm or less. When the thickness of the positive electrode 203 is 10 μm or more, it is easy to ensure a sufficient energy density for the battery 2000. When the thickness of the positive electrode 203 is 500 μm or less, it is easier for the battery 2000 to operate at a high output.

[0208] In order to reduce the interfacial resistance with the solid electrolyte, the positive electrode active material may be coated with a coating material. As the coating material, a material with low electronic conductivity can be used. As the coating material, an oxide material, an oxide solid electrolyte, etc. can be used. As the coating material, the materials exemplified in Embodiment 1 can be used.

[0209] For the purpose of improving the adhesion between particles, at least one selected from the electrolyte layer 202 and the positive electrode 203 may contain a binder. As the binder, the materials exemplified in Embodiment 1 can be used. The binder can be used alone or two or more of them can be used in combination.

[0210] As an adhesive, an elastomer can be used from the viewpoint of excellent adhesiveness. An elastomer refers to a polymer having elasticity. The elastomer used as an adhesive can be a thermoplastic elastomer or a thermosetting elastomer. The adhesive may contain a thermoplastic elastomer. As the elastomer, the materials exemplified in Embodiment 1 can be used. When the adhesive contains an elastomer, for example, high filling can be achieved for the electrolyte layer 202 or the positive electrode 203 by thermal compression during the manufacture of the battery 2000.

[0211] For the purpose of facilitating the transfer of lithium ions and improving the output characteristics of the battery 2000, at least one selected from the electrode layer 110 of the negative electrode 201, the electrolyte layer 202, and the positive electrode 203 may contain a non-aqueous electrolyte, a gel electrolyte, or an ionic liquid.

[0212] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent. As the non-aqueous solvent, a cyclic carbonate solvent, a chain carbonate solvent, a cyclic ether solvent, a chain ether solvent, a cyclic ester solvent, a chain ester solvent, a fluorine solvent, etc. can be used. As the cyclic carbonate solvent, ethylene carbonate, propylene carbonate, butylene carbonate, etc. can be cited. As the chain carbonate solvent, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, etc. can be cited. As the cyclic ether solvent, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, etc. can be cited. As the chain ether solvent, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc. can be cited. As the cyclic ester solvent, γ-butyrolactone, etc. can be cited. As the chain ester solvent, methyl acetate, etc. can be cited. As the fluorine solvent, fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoromethyl ethyl carbonate, difluoromethyl carbonate, etc. can be cited. As the non-aqueous solvent, one non-aqueous solvent selected from the above can be used alone, or a mixture of two or more non-aqueous solvents selected from the above can be used.

[0213] The non-aqueous electrolyte may contain at least one fluorine solvent selected from fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoromethyl ethyl carbonate, and difluoromethyl carbonate.

[0214] As the lithium salt, LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), LiC(SO2CF3)3, etc. can be cited. As the lithium salt, one lithium salt selected from the above can be used alone, or a mixture of two or more lithium salts selected from the above can be used. The concentration of the lithium salt in the non-aqueous electrolyte can be 0.5 mol / L or more and 2 mol / L or less.

[0215] As the gel electrolyte, a material containing a non-aqueous electrolyte in a polymer material can be used. As the polymer material, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a polymer having an ethylene oxide bond, etc. can be mentioned.

[0216] The cation constituting the ionic liquid can be an aliphatic chain-like quaternary cation such as tetraalkylammonium or tetraalkylphosphonium, an aliphatic cyclic ammonium such as pyrrolidinium, morpholinium, imidazolinium, tetrahydropyrimidinium, piperazinium, piperidinium, etc., a nitrogen-containing heterocyclic aromatic cation such as pyridinium or imidazolium, etc. The anion constituting the ionic liquid can be PF6 - 、BF4 - 、SbF6 - 、AsF6 - 、SO3CF3 - 、N(SO2F)2 - 、N(SO2CF3)2 - 、N(SO2C2F5)2 - 、N(SO2CF3)(SO2C4F9) - 、C(SO2CF3)3 - etc. The ionic liquid may contain a lithium salt.

[0217] For the purpose of improving the electronic conductivity, at least one of the electrode layer 110 of the negative electrode 201 and the positive electrode 203 may contain a conductive aid. As the conductive aid, the materials exemplified in Embodiment 1 can be used.

[0218] For the purpose of improving the dispersibility of the solid electrolyte and the active material, at least one of the electrode layer 110 of the negative electrode 201 and the positive electrode 203 may contain a dispersant. As the dispersant, the materials exemplified in Embodiment 1 can be used.

[0219] As the shape of the battery 2000, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, a laminated type, etc. can be mentioned.

[0220] The battery 2000 can be manufactured, for example, by the following method. First, a current collector 100, a material for forming the electrode layer 110, a material for forming the electrolyte layer 202, a material for forming the positive electrode 203, and a current collector for the positive electrode 203 are prepared respectively. Using them, a laminate in which the negative electrode 201, the electrolyte layer 202, and the positive electrode 203 are arranged in this order is produced by a known method. Thereby, the battery 2000 can be manufactured.

[0221] Figure 4A cross-sectional view of the battery 2001 according to the modified example. The battery 2001 may be a laminate of a plurality of batteries 2000. The battery 2001 can be manufactured by the following method. A negative electrode (first negative electrode 211) formed by laminating an electrode layer 110 on a current collector 100 having a substrate 101 and a coating layer 102 covering the substrate on both sides thereof, a first electrolyte layer 212, and a first positive electrode 213 are sequentially arranged. On the other hand, an electrode layer 110 (second negative electrode 221), a second electrolyte layer 222, and a second positive electrode 223 are sequentially arranged on the surface of the current collector 100 on the opposite side of the surface on which the first negative electrode 211 is laminated. Thus, a laminate in which a first positive electrode 213, a first electrolyte layer 212, a first negative electrode 211, a current collector 100, a second negative electrode 221, a second electrolyte layer 222, and a second positive electrode 223 are sequentially arranged is obtained. The battery 2001 can be manufactured by compression molding of this laminate using a press at a high temperature, for example, at a temperature of 120 °C or higher and 195 °C or lower. According to such a method, it is possible to manufacture a laminate of two batteries 2000 while suppressing warping of the battery, and it is possible to manufacture a high-output battery 2001 with higher efficiency. It should be noted that in the manufacture of the battery 2001, there is no particular limitation on the order in which the respective members are laminated. For example, by arranging the first negative electrode 211 and the second negative electrode 221 on the current collector 100 and then sequentially laminating the first electrolyte layer 212, the second electrolyte layer 222, the first positive electrode 213, and the second positive electrode 223, a laminate of two batteries 2000 can be manufactured. Further, by separately preparing a plurality of batteries 2001 and current collectors for the positive electrode and alternately laminating the batteries 2001 and the positive electrode current collectors, a laminate of the batteries 2000 can be manufactured. By adopting such a method, the batteries 2000 can be laminated with high efficiency.

[0222] (Other embodiments)

[0223] (Supplementary note)

[0224] Based on the description of the above embodiments, the following technology is disclosed.

[0225] (Technology 1)

[0226] An electrode plate, comprising: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing conductive carbon and a first binder, the electrode layer containing a second binder, the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 mass ppm or more and 400 mass ppm or less.

[0227] According to such a configuration, in addition to being able to improve the peel strength between the electrode layer and the current collector, it is also possible to improve the uniformity of the peel strength.

[0228] (Technology 2)

[0229] The electrode plate according to Technology 1, wherein the first adhesive contains polyimide. Polyimide has a tendency to exhibit higher heat resistance. Therefore, even if the member including the current collector is compressed at a high temperature, the coating layer is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0230] (Technology 3)

[0231] The electrode plate according to Technology 1 or 2, wherein the substrate contains aluminum or an aluminum alloy. According to such a configuration, not only can the peel strength between the electrode layer and the current collector be improved, but also the mass energy density of the electrochemical device can be improved.

[0232] (Technology 4)

[0233] The electrode plate according to any one of Technologies 1 to 3, wherein the electrode layer further contains a solid electrolyte. The electrode plate of the present disclosure is suitable for an electrochemical device, particularly a battery, that includes a solid electrolyte in the electrode layer.

[0234] (Technology 5)

[0235] The electrode plate according to Technology 4, wherein the solid electrolyte contains a sulfide solid electrolyte. Since the sulfide solid electrolyte has more excellent ionic conductivity and moldability, it is particularly suitable as the solid electrolyte of the electrode layer.

[0236] (Technology 6)

[0237] A battery including: a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode, wherein at least one selected from the positive electrode and the negative electrode includes the electrode plate according to any one of Technologies 1 to 5.

[0238] Since the peel strength between the electrode layer and the current collector is high and the uniformity of the peel strength is also high, the battery using the electrode plate having such an electrode layer and current collector has excellent cycle characteristics.

[0239] Examples

[0240] Hereinafter, the details of the present disclosure will be described using examples and comparative examples. It should be noted that the current collector, electrode plate, and battery of the present disclosure are not limited to the following examples.

[0241] <Example 1>

[0242] [Fabrication of Current Collector]

[0243] A coating was prepared by kneading conductive carbon, a first binder, and a solvent. As the conductive carbon, carbon black and graphite were used. As the first binder, polyvinylidene fluoride, which is a non-aromatic super engineering plastic, was used. Next, the coating was applied to one side of an aluminum alloy foil (A3003 foil, thickness: 15 μm) to form a coated film. The coated film was dried at 165 °C to form a coating layer. Further, the coating was applied to the other side of the aluminum alloy foil to form a coated film. The coated film was dried at 165 °C to form a coating layer. Thus, a current collector having coating layers on both sides was produced. In the current collector of Example 1, the mass per unit area of the coating layer was 0.94 g / m 2 .

[0244] [Solvent]

[0245] In all of the following processes, as the solvent, a commercially available dehydrated solvent or a solvent dehydrated by nitrogen bubbling was used. The water content in the solvent was 10 mass ppm or less.

[0246] [Preparation of the second binder solution]

[0247] The second binder solution was prepared by adding a solvent to the second binder to dissolve or disperse the second binder in the solvent. The concentration of the binder in the second binder solution was 5 mass% or more and 10 mass% or less.

[0248] As the solvent for the second binder solution, tetralin was used. As the styrene-based elastomer constituting the second binder, a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON Corporation, G1633) in a mass ratio of 1:1 was used. "Tuftec" is a registered trademark of Asahi Kasei Corporation.

[0249] [Determination of the molar fraction of repeating units derived from styrene]

[0250] The molar fraction of repeating units derived from styrene in the styrene-based elastomer was determined by the following method. First, for the measurement sample containing the styrene-based elastomer, proton nuclear magnetic resonance ( 1 1H-NMR) measurement was performed using a nuclear magnetic resonance apparatus (manufactured by Bruker Corporation, AVANCE500). As the measurement sample, a product obtained by dissolving the styrene-based elastomer in CDCl3 was used. CDCl3 contained 0.05% of tetramethylsilane (TMS). 11H-NMR measurements were carried out under the conditions of a resonance frequency of 500 MHz and a measurement temperature of 23 °C. The integral values of the peaks from the styrene backbone and the integral values of the peaks from other backbones outside the styrene backbone were determined from the obtained NMR spectra. Using the determined integral values, the molar fraction of the repeating units derived from styrene in the styrene-based elastomer was determined.

[0251] [Measurement of weight-average molecular weight]

[0252] The weight-average molecular weight (M w ) of the styrene-based elastomer constituting the second binder was measured by gel permeation chromatography (GPC) using a high-speed GPC apparatus (manufactured by Tosoh Corporation, HLC-832-GPC). As the measurement sample, a product obtained by dissolving the styrene-based elastomer in chloroform and filtering it through a filter with a pore size of 0.2 μm was used. As the columns, two Super HM-H columns manufactured by Tosoh Corporation were used. A differential refractometer was used in the GPC measurement. The GPC measurement was carried out under the conditions of a flow rate of 0.6 mL / min and a column temperature of 40 °C. As the standard sample, monodisperse polystyrene (manufactured by Tosoh Corporation) was used. By the GPC measurement, the weight-average molecular weight (M w ) of the styrene-based elastomer was determined.

[0253] [Fabrication of electrode plate]

[0254] In an argon glove box with a dew point of -60 °C or lower, tetralin and a second binder solution were added to the Li2S-P2S5-based glass-ceramic (hereinafter referred to as "LPS"). The mixing of these materials was carried out at a mass ratio of LPS: second binder = 100:3 and adjusted so that the solid content concentration (NV) became 47. Next, for the obtained mixture, a homogenizer (manufactured by Asone Corporation, HG-200) and a stirrer (manufactured by As one Corporation, K-20S) were used to perform high-shear dispersion and kneading to prepare a slurry. Next, the slurry was coated on the coating layer of the current collector, and the obtained coating film was dried at 100 °C for 1 hour in a vacuum atmosphere to fabricate the electrode plate of Example 1.

[0255] <Example 2>

[0256] An electrode plate of Example 2 was fabricated in the same manner as in Example 1, except that a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON Corporation, G1633) in a mass ratio of 2:3 was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 46.

[0257] <Example 3>

[0258] Except that soluble polyimide, which is an aromatic super engineering plastic, was used as the first binder, the electrode plate of Example 3 was fabricated in the same manner as in Example 1. In the current collector of Example 3, the mass per unit area of the coating layer was 1.3 g / m 2 .

[0259] <Example 4>

[0260] Except that soluble polyimide was used as the first binder, the electrode plate of Example 4 was fabricated in the same manner as in Example 2. In the current collector of Example 4, the mass per unit area of the coating layer was 1.3 g / m 2 .

[0261] <Comparative Example 1>

[0262] Except that the coating layer was not provided on the current collector, the electrode plate of Comparative Example 1 was fabricated in the same manner as in Example 1.

[0263] <Comparative Example 2>

[0264] Except that the coating layer was not provided on the current collector, the electrode plate of Comparative Example 2 was fabricated in the same manner as in Example 2.

[0265] <Comparative Example 3>

[0266] Except that a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON Corporation, G1633) in a mass ratio of 19:1 was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 55, the electrode plate of Comparative Example 3 was fabricated in the same manner as in Example 1.

[0267] <Comparative Example 4>

[0268] Except that a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON Corporation, G1633) in a mass ratio of 1:4 was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 45, the electrode plate of Comparative Example 4 was fabricated in the same manner as in Example 1.

[0269] <Comparative Example 5>

[0270] The electrode plate of Comparative Example 5 was produced in the same manner as in Example 1, except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei Corporation, Asaprene Y031) was used as the styrenic elastomer constituting the second binder. "Asaprene" is a registered trademark of Asahi Kasei Corporation.

[0271] <Comparative Example 6>

[0272] The electrode plate of Comparative Example 6 was produced in the same manner as in Example 1, except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei Corporation, Asaprene XB120) was used as the styrenic elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 43.

[0273] [Peel Test]

[0274] Using the method described previously, the peel strength and coefficient of variation thereof of the electrode plates of the examples and comparative examples were measured. The results are shown in Table 1. Regarding the measurement of the peel strength, each electrode plate was subjected to three measurements. The "peel strength" and "coefficient of variation" shown in Table 1 are the averages of the values obtained from the three measurements.

[0275] Table 1

[0276]

[0277] The current collectors of the electrode plates of Comparative Example 1 and Comparative Example 2 do not have a coating layer. Therefore, the peel strength of the electrode plates of Comparative Example 1 and Comparative Example 2 is low.

[0278] In the electrode plates of Comparative Example 4 and Comparative Example 5, the total nitrogen content of the second binder in the electrode layer is as low as 106 ppm and 107 ppm. Therefore, the peel strength of the electrode plates of Comparative Example 4 and Comparative Example 5 is low. In the electrode plate of Comparative Example 6, the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer is as low as 0.09. Therefore, the peel strength of the electrode plate of Comparative Example 6 is low.

[0279] In the electrode plate of Comparative Example 3, the total nitrogen content of the second binder in the electrode layer is 446 ppm. Although the electrode plate of Comparative Example 3 shows a high peel strength, its coefficient of variation is large. That is, the fluctuation of the peel strength is large.

[0280] As can be seen from the results shown in Table 1, the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer and the total nitrogen amount of the second binder of the electrode layer are related to the peel strength and its coefficient of variation. In the electrode plates of Examples 1 to 4 containing a styrene-based elastomer having a molar fraction of the repeating unit derived from styrene of 0.12 or more and a total nitrogen amount of 120 ppm or more and 400 ppm or less, the peel strength between the electrode layer and the current collector showed a high value, and the coefficient of variation of the peel strength showed a low value.

[0281] Figure 5A It is a graph obtained from the peel test of the electrode plate of Example 1. Figure 5B It is a graph obtained from the peel test of the electrode plate of Comparative Example 3. The horizontal axis represents the moving amount (mm) of the jig. That is, the horizontal axis corresponds to the position of the peeled electrode layer. The vertical axis represents the measured peel strength (N / m). In the calculation of the peel strength and the coefficient of variation of Example 1, the data in the range of a moving amount of 12 mm to 17 mm was used. In the calculation of the peel strength and the coefficient of variation of Comparative Example 3, the data in the range of a moving amount of 11 mm to 16 mm was used. The reason is that it is considered that by selecting the stable range after the unstable range where peeling starts, the deviation of the data can be minimized as much as possible, and thus the correct peel strength and coefficient of variation can be calculated.

[0282] As Figure 5B shown, the deviation of the peel strength of the electrode plate of Comparative Example 3 is large. And as Figure 5A shown, the deviation of the peel strength of the electrode plate of Example 1 is small. In this way, according to the technology of the present disclosure, not only can the peel strength between the electrode layer and the current collector be improved, but also its uniformity can be improved.

[0283] Industrial Applicability

[0284] The electrode plate of the present disclosure can be used in electrochemical devices such as batteries and capacitors.

Claims

1. An electrode plate, comprising: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing conductive carbon and a first binder, the electrode layer containing a second binder, the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 mass ppm or more and 400 mass ppm or less.

2. The electrode plate according to claim 1, wherein, The first binder contains polyimide.

3. The electrode plate according to claim 1, wherein, The substrate contains aluminum or an aluminum alloy.

4. The electrode plate according to claim 1, wherein, The electrode layer further contains a solid electrolyte.

5. The electrode plate according to claim 4, wherein, The solid electrolyte contains a sulfide solid electrolyte.

6. A battery, comprising: a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode, at least one selected from the positive electrode and the negative electrode containing the electrode plate according to claim 1.

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