Electrode plates and batteries

Abstract

To provide an electrode plate capable of improving uniformity of peel strength while improving peel strength between an electrode layer and a current collector.SOLUTION: A disclosed electrode plate 1000 includes: a current collector 100 having a substrate 101 and a coating layer 102 coating the substrate 101; and an electrode layer 110 placed over the current collector 100. The coating layer 102 contains a conductive carbon 103 and a first binder 104. The electrode layer 110 contains a second binder 113. The second binder 113 contains a styrene-based elastomer in which a mole fraction of repeating units derived from styrene is 0.12 or more and a total nitrogen content is 120 mass ppm or more and 400 mass ppm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to electrode plates and batteries. [Background technology]

[0002] Current collectors are essential components of electrochemical devices such as batteries and capacitors. An electrode layer, such as an active material layer, is placed on top of the current collector. The adhesion between the current collector and the electrode layer affects the performance of the electrochemical device. Current collectors having a substrate and a coating layer are known to improve adhesion.

[0003] Patent Document 1 describes a current collector for an energy storage device in which a coating layer is formed on one or both sides of a sheet-like metal substrate. The coating layer comprises a powdered carbon material and a binder. The binder comprises polyvinylidene fluoride (PVDF). The coating layer improves the adhesion between the metal substrate and the active material layer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2018-190527 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present disclosure aims to provide an electrode plate suitable for improving not only the peel strength between the electrode layer and the current collector, but also the uniformity of the peel strength. [Means for solving the problem]

[0006] This disclosure is, A current collector having a substrate and a coating layer covering the substrate, An electrode layer arranged on the current collector, Equipped with, The coating layer comprises conductive carbon and a first binder. The electrode layer includes a second binder, The second binder contains a styrene-based elastomer having a mole fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 ppm by mass or more and 400 ppm by mass or less. An electrode plate is provided. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an electrode plate suitable for improving not only the peel strength between the electrode layer and the current collector, but also the uniformity of the peel strength. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view of the electrode plate according to Embodiment 1. [Figure 2] Figure 2 is a cross-sectional view of an electrode plate according to a modified example. [Figure 3] Figure 3 is a cross-sectional view of the battery according to Embodiment 2. [Figure 4] Figure 4 is a cross-sectional view of a modified battery. [Figure 5A] Figure 5A is a graph obtained from the peel test of the electrode plate in Example 1. [Figure 5B] Figure 5B is a graph obtained from the peel test of the electrode plate in Comparative Example 3. [Modes for carrying out the invention]

[0009] (Knowledge that forms the basis of this disclosure) Improving the current collector is one way to improve 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. Focusing on this point, the inventors attempted to improve the adhesion between the electrode layer and the current collector by improving the binder of the electrode layer, and came up with the technology of this disclosure.

[0010] The adhesion between the electrode layer and the current collector can be quantified as peel strength. The uniformity of the peel strength can be quantified as the coefficient of variation of the peel strength.

[0011] The embodiments of this disclosure will be described below with reference to the drawings. This disclosure is not limited to the embodiments described below.

[0012] (Embodiment 1) Figure 1 is a cross-sectional view of an electrode plate 1000 according to Embodiment 1. The electrode plate 1000 comprises 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 is in contact with the electrode layer 110. The coating layer 102 contains conductive carbon 103 and a first binder 104. The electrode layer 110 contains a second binder 113. The second binder 113 contains a styrene-based elastomer in which the mole fraction of repeating units derived from styrene is 0.12 or more, and the total nitrogen content is 120 ppm by mass or more and 400 ppm by mass or less.

[0013] With the above configuration, not only can the peel strength between the electrode layer 110 and the current collector 100 be improved, but the uniformity of the peel strength can also be improved. Furthermore, the cycle characteristics of a battery equipped with 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-state batteries, and capacitors. The electrode plate 1000 is particularly suitable as an electrode plate for all-solid-state secondary batteries.

[0014] The high uniformity of the peel strength between the electrode layer 110 and the current collector 100 means that there is little variation in performance among multiple electrode plates 1000. Using such electrode plates 1000 makes it possible to manufacture electrochemical devices of consistent quality, which in turn improves yield.

[0015] In electrode plate 1000, the reason for the improvement in peel strength and uniformity is not entirely clear, but it is presumed that the interaction between the aromatic rings contained in the styrene-based elastomer and the conductive carbon influences the peel strength and uniformity. One example of this interaction is the π-π interaction. The π-π interaction involves 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 rings of the styrene-based elastomer. Furthermore, in current collector 101, if the coating layer 102 covers only a portion of the main surface of the substrate 101, the electrode layer 110 may 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 influences the peel strength and uniformity. One example of this interaction is the intermolecular interaction.

[0016] The nitrogen-containing styrene elastomer may also be a styrene elastomer having a nitrogen-containing modifying group. With such an elastomer, the total amount of nitrogen can be kept within the above range by adjusting the amount of nitrogen-containing modifying group.

[0017] The electrode layer 110 may contain a solid electrolyte 111, an active material 112, or both.

[0018] [Current collector] The current collector 100 includes a substrate 101 and a coating layer 102.

[0019] The current collector 100 has, for example, a plate-like or foil-like shape. The thickness of the current collector 100 may be 0.1 μm or more and 1 mm or less, 1 μm or more and 100 μm or less, or 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 improved, and damage to 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 improved by reducing the weight of the current collector 100. In other words, by appropriately adjusting the thickness of the current collector 100, the electrochemical device can be manufactured stably and the energy density of the electrochemical device can be improved.

[0020] <Coating layer> The coating layer 102 may completely cover the main surface of the substrate 101, or it may partially cover the main surface of the substrate 101. "Main surface" refers to the surface of the substrate 101 that has the largest surface area. The coating layer 102 is located between the substrate 101 and the electrode layer 110, and is in contact with both the substrate 101 and the electrode layer 110. The shape of the coating layer 102 may be dot-shaped, striped, or the like.

[0021] Examples of conductive carbon 103 included in the coating layer 102 include graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black (AB) and Ketjen black (KB), conductive fibers such as carbon fiber (CF), vapor-deposited carbon (VGCF®), and carbon nanotubes (CNT), and nanocarbons such as graphene. One conductive carbon selected from these may be used alone, or two or more conductive carbons selected from these may be used.

[0022] The first binder 104 contained in the coating layer 102 may contain aromatic super engineering plastics. Aromatic super engineering plastics refer to engineering plastics that contain aromatic rings in their main chain skeleton and have a continuous usable temperature of 150°C or higher. Examples of aromatic super engineering plastics include polybenzimidazole (PBI), polyimide (PI), polyetherketone (PEKEKK), polyamideimide (PAI), polyetherketone (PEEK), polyetherketone (PEK), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI), polysulfone (PSU), polyparaphenylene (PPP), and polyarylate (PAR). A mixture containing two or more selected from these may be used as the first binder 104. Aromatic super engineering plastics exhibit high heat resistance. Therefore, when an aromatic super engineering plastic is included in the coating layer 102 as the first binder 104, the coating layer 102 is less likely to adhere to production equipment such as a press machine, even if the component including the current collector 100 is compressed at a high temperature. As a result, the productivity of electrochemical devices is improved.

[0023] The aromatic super engineering plastic may be polyimide (PI). Polyimide tends to exhibit higher heat resistance. Therefore, even if the component containing the current collector 100 is compressed at high temperatures, the coating layer 102 is less likely to adhere to production equipment such as presses. As a result, the productivity of electrochemical devices is improved.

[0024] The first binder 104 may contain additional binders other than aromatic super engineering plastics. Alternatively, the first binder 104 may be aromatic super engineering plastics. In other words, the first binder 104 may contain only aromatic super engineering plastics.

[0025] Additional binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamide-imide, polyacrylonitrile, polyacrylic acid, polymethyl polyacrylate, polyethyl polyacrylate, polyhexyl polyacrylate, polymethacrylic acid, polymethyl polymethacrylate (PMMA), polyethyl polymethacrylate, polyhexyl polymethacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polycarbonate, polyethersulfone, polyetherketone, polyetheretherketone, polyphenylene sulfide, hexafluoropolypropylene, styrene-butadiene rubber, carboxymethylcellulose, and ethylcellulose. As an additional binder, copolymers synthesized using two or more monomers selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, butadiene, isoprene, styrene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid esters, acrylic acid, and hexadiene may also be used. As an additional binder, one selected from these may be used alone, or a mixture containing two or more selected from these may be used.

[0026] The additional binder may include an elastomer from the viewpoint of excellent binding properties. An elastomer refers to a polymer having rubber elasticity. The elastomer used as a binder may be a thermoplastic elastomer or a thermosetting elastomer. Examples of elastomers include the aforementioned styrene-based elastomers, as well as 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), and acrylate butadiene rubber (ABR). A mixture containing two or more selected from these may also be used.

[0027] The content of the first binder 104 in the coating layer 102 is not particularly limited, and may be, for example, 20% by mass or more and 95% by mass or less, 40% by mass or more and 90% by mass or less, or 55% by mass or more and 85% by mass or less. When the content of the first binder 104 is 95% by mass or less, the electrical conductivity of the coating layer 102 is improved, making it possible to increase the output of the electrochemical device. When the content of the first binder 104 is 20% by mass or more, the presence of sufficient first binder 104 tends to suppress peeling of the coating layer 102.

[0028] The coating layer 102 may contain conductive materials other than conductive carbon 103. Examples of conductive materials other than conductive carbon include conductive fibers such as metal fibers, conductive powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene.

[0029] The coating layer 102 may contain elements or components other than conductive carbon 103 and the first binder 104. These other elements or components may be added to the coating layer 102 by contamination or other means. For example, an unavoidable 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 unavoidable oxides or the like.

[0030] The coating layer 102 can be fabricated, for example, by sputtering the coating layer material onto the surface of the substrate 101. The coating layer 102 may also be fabricated by applying a solution or dispersion containing the coating layer material to the surface of the substrate 101. The application of the solution or dispersion can be carried out using a gravure coater, die coater, or the like.

[0031] The mass per unit area of ​​the coating layer 102 is not particularly limited, for example, 0.01 g / m². 2 More than 5g / m 2 It may also be less than 0.1 g / m 2 More than 3g / m 2 The following may also be acceptable: 0.5g / m 2 More than 2g / m 2 The following is also acceptable: Mass per unit area of ​​0.01 g / m² 2 If the above is true, contact between the substrate 101 and the electrode layer can be prevented, thereby suppressing corrosion of the substrate 101. 2 In the following cases, the electrical resistance of the coating layer 102 decreases, making it easier for the electrochemical device to operate at high power.

[0032] The thickness of the coating layer 102 is not particularly limited and may be, for example, 0.001 μm or more and 10 μm or less, 0.01 μm or more and 5 μm or less, or 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, thereby suppressing corrosion of the substrate 101. When the thickness of the coating layer 102 is 10 μm or less, the electrical resistance of the coating layer 102 is reduced, making it easier to operate the electrochemical device at high power.

[0033] <Circuit board> The substrate 101 may have a shape such as foil or plate. The substrate 101 may be made of a metal or an alloy. Examples of metals include aluminum, iron, nickel, and copper. Examples of alloys include aluminum alloys and stainless steel (SUS). The substrate 101 may also contain aluminum or an aluminum alloy.

[0034] The substrate 101 may contain aluminum as its main component. "The substrate 101 contains aluminum as its main component" means that the aluminum content in the substrate 101 is 50% by mass or more. Aluminum is a lightweight metal with high electrical conductivity. Therefore, an electrode plate 1000 equipped with a substrate 101 containing aluminum as its main component can improve the gravimetric energy density of an electrochemical device. The substrate 101 containing aluminum as its main component may further contain elements other than aluminum. Note that if the substrate 101 consists only of aluminum, i.e., if the aluminum content in the substrate 101 is 100%, the strength of the substrate 101 may decrease. Therefore, the substrate 101 may contain elements other than aluminum. The aluminum content in the substrate 101 may be 99% by mass or less, or 90% by mass or less.

[0035] The substrate 101 may contain an aluminum alloy. Aluminum alloys are lightweight and have high strength. Therefore, an electrode plate 1000 equipped with a substrate 101 containing an aluminum alloy can realize an electrochemical device that achieves both high gravimetric energy density and high durability. The aluminum alloy is not particularly limited and examples include Al-Cu alloy, Al-Mn alloy, Al-Mn-Cu alloy, Al-Fe-Cu alloy, etc.

[0036] An Al-Mn alloy may be used as the material for the substrate 101. Al-Mn alloys have high strength, as well as excellent formability and corrosion resistance. Therefore, an electrode plate 1000 equipped with an Al-Mn alloy substrate 101 can improve the battery's cycle characteristics.

[0037] The thickness of the substrate 101 is not particularly limited and may be, for example, 0.1 μm or more and 50 μm or less, or 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 damage to 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.

[0038] [Electrode layer] The electrode layer 110 includes a second binder 113. The electrode layer 110 may further include a solid electrolyte 111 and an active material 112. The solid electrolyte 111, the active material 112, and the second binder 113 will be described in detail below.

[0039] <Solid electrolyte> The solid electrolyte 111 may contain a sulfide solid electrolyte. The sulfide solid electrolyte may contain lithium. By using a sulfide solid electrolyte containing lithium as the solid electrolyte 111, a lithium secondary battery can be manufactured using an electrode plate 1000 containing this sulfide solid electrolyte.

[0040] 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 contain only sulfide solid electrolytes.

[0041] In the present disclosure, the "oxide solid electrolyte" means a solid electrolyte containing oxygen. The oxide solid electrolyte may further contain anions other than oxygen, such as anions other than sulfur and halogen elements.

[0042] In the present disclosure, the "halide solid electrolyte" means a solid electrolyte containing a halogen element and not containing sulfur. In the present disclosure, a solid electrolyte not containing sulfur means a solid electrolyte represented by a composition formula not containing a sulfur element. Therefore, a solid electrolyte containing a very small amount of sulfur component, for example, sulfur is 0.1 mass% or less, is included in the solid electrolyte not containing sulfur. The halide solid electrolyte may further contain oxygen as an anion other than the halogen element.

[0043] Examples of the sulfide solid electrolyte include, for example, Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 and the like can be used. To these, LiX, Li2O, MO q , Li p MO q and the like may be added. The element X in "LiX" is at least one selected from the group consisting of F, Cl, Br, and I. The element M in "MO q " and "Li p MO q " is at least one selected from the group consisting of P, Si, Ge, B, Al, Ga, In, Fe, and Zn. The element M in "MO q " and "Li p MO qIn this expression, p and q are independent natural numbers.

[0044] As the sulfide solid electrolyte, for example, Li2S-P2S5 glass ceramics may be used. Li2S-P2S5 glass ceramics may contain LiX, Li2O, and MO q Li p MO q Other materials may be added, and two or more selected from LiCl, LiBr, and LiI may be added. Since Li2S-P2S5-based glass ceramics are relatively soft materials, a more durable battery can be manufactured using an electrode plate 1000 containing Li2S-P2S5-based glass ceramics.

[0045] Examples of oxide solid electrolytes include NASICON-type solid electrolytes, such as LiTi2(PO4)3 and its elemental substitutions, and (LaLi)TiO3-based perovskite-type solid electrolytes, Li 14 ZnGe4O 16 , LiSICON-type solid electrolytes such as Li4SiO4, LiGeO4 and their elemental substitutions, Li7La3Zr2O 12 Garnet-type solid electrolytes, such as those represented by elemental substitutions thereof, Li-BO compounds such as Li3PO4 and its N-substituted counterparts, LiBO2 and Li3BO3, with Li2SO4, Li2CO3, etc. added as a base, as well as glass ceramics, can be used.

[0046] The halide solid electrolyte includes, for example, Li, M1, and X. M1 is at least one selected from the group consisting of metal elements and metalloid elements other than Li. X is at least one selected from the group consisting of F, Cl, Br, and I. Because the halide solid electrolyte has high thermal stability, it can improve the safety of the battery. Furthermore, because the halide solid electrolyte does not contain sulfur, it can suppress the generation of hydrogen sulfide gas.

[0047] In this disclosure, “metallic elements” are B, Si, Ge, As, Sb, and Te.

[0048] In this disclosure, “metallic elements” refers to all elements in groups 1 through 12 of the periodic table, excluding hydrogen, and all elements in groups 13 through 16 of the periodic table, excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se.

[0049] In other words, in this disclosure, "metalloid elements" and "metal elements" are groups of elements that can become cations when they form inorganic compounds with halogen elements.

[0050] For example, the halide solid electrolyte may be a material represented by the following compositional formula (1). Li α M1 β X γ ...Equation (1)

[0051] In the above empirical formula (1), α, β, and γ are each independently greater than 0. γ can be 4, 6, etc.

[0052] With the above configuration, the ionic conductivity of the halide solid electrolyte is improved. Therefore, the ionic conductivity of the electrode plate 1000 can be improved. When this electrode plate 1000 is used in a battery, the cycle characteristics of the battery can be further improved.

[0053] In the above compositional formula (1), element M1 may include Y (=yttrium). That is, the halide solid electrolyte may contain Y as a metallic element.

[0054] A halide solid electrolyte containing Y may be represented, for example, by the following compositional formula (2). Li a Me b Y c X6...Formula (2)

[0055] 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 the group consisting of metal elements and metalloid elements other than Li and Y. m represents the valence of the element Me. When the element Me contains multiple elements, mb is the total value of the product of the composition ratio of each element and the valence of that 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 composition formula (2), the element X is at least one selected from the group consisting of F, Cl, Br, and I.

[0056] The element Me may be, for example, at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, Gd, and Nb.

[0057] 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 can be further improved, and the output characteristics of the battery can be further improved.

[0058] The halide solid electrolyte may be a material represented by the following composition formula (A1). Li 6-3d Y d X6 ··· Formula (A1)

[0059] In the composition formula (A1), the element X is at least one selected from the group consisting of Cl, Br, and I. In the composition formula (A1), d satisfies 0 < d < 2.

[0060] The halide solid electrolyte may be a material represented by the following composition formula (A2). Li3YX6 ··· Formula (A2)

[0061] In the empirical formula (A2), element X is at least one selected from the group consisting of Cl, Br, and I.

[0062] The halide solid electrolyte may be a material represented by the following compositional formula (A3). Li 3-3δ Y 1+δ Cl6...Formula (A3)

[0063] In empirical formula (A3), δ satisfies 0 < δ ≤ 0.15.

[0064] The halide solid electrolyte may be a material represented by the following compositional formula (A4). Li 3-3δ Y 1+δ Br6...Formula (A4)

[0065] In empirical formula (A4), δ satisfies 0 < δ ≤ 0.25.

[0066] The halide solid electrolyte may be a material represented by the following compositional formula (A5). Li 3-3δ+a Y 1+δ-a Me a Cl 6-x-y Br x I y ...Formula (A5)

[0067] In empirical formula (A5), the element Me is at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn.

[0068] Furthermore, in the above composition formula (A5), -1 < δ < 2, 0 <a<3、 0 < (3 - 3δ + a), 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0≦y≦6, and (x+y)≦6, The conditions are met.

[0069] The halide solid electrolyte may be a material represented by the following compositional formula (A6). Li 3-3δ Y 1+δ-a Me a Cl 6-x-y Br x I y ...Formula (A6)

[0070] In the composition formula (A6), the element Me is at least one selected from the group consisting of Al, Sc, Ga, and Bi.

[0071] Furthermore, in the above composition formula (A6), -1 < δ < 1, 0 <a<2、 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0≦y≦6, and (x+y)≦6, The conditions are met.

[0072] The halide solid electrolyte may be a material represented by the following compositional formula (A7). Li 3-3δ-a Y 1+δ-a Me a Cl 6-x-y Br x I y ...Formula (A7)

[0073] In the above compositional formula (A7), the element Me is at least one selected from the group consisting of Zr, Hf, and Ti.

[0074] Furthermore, in the above composition formula (A7), -1 < δ < 1, 0 <a<1.5、 0 < (3 - 3δ - a), 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0≦y≦6, and (x+y)≦6, The conditions are met.

[0075] The halide solid electrolyte may be a material represented by the following compositional formula (A8). Li 3-3δ-2a Y 1+δ-a Me a Cl 6-x-y Br x I y ··· Formula (A8)

[0076] In the compositional formula (A8), the element Me is at least one selected from the group consisting of Ta and Nb.

[0077] Furthermore, in the above compositional formula (A8), -1 < δ < 1, 0 < a < 1.2, 0 < (3 - 3δ - 2a), 0 < (1 + δ - a), 0 ≦ x ≦ 6, 0 ≦ y ≦ 6, and (x + y) ≦ 6, is satisfied.

[0078] 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 the group consisting of Nb and Ta. Also, X2 is at least one selected from the group consisting of F, Cl, Br, and I.

[0079] The compound containing Li, M2, X2, and O (oxygen) may be represented by, for example, the compositional formula: Li<00000�5>M2O<00000�6>X2<00000�7>Here, x may satisfy 0.1 < x < 7.0. y may satisfy 0.4 < y < 1.9.

[0080] More specifically, as the halide solid electrolyte, for example, Li3Y(Cl,Br,I)6, Li<00000�8>Y<00000�9>(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., can be used. In this disclosure, when an element in a formula is represented as "(Al,Ga,In)", this notation indicates at least one element selected from the group of elements in parentheses. That is, "(Al,Ga,In)" is synonymous with "at least one selected from the group consisting of Al, Ga, and In". The same applies to other elements.

[0081] As a polymeric solid electrolyte, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound may have an ethylene oxide structure. Polymeric compounds having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further improved. Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. A single lithium salt may be used, or two or more may be used in combination.

[0082] Examples of complex hydride solid electrolytes that can be used include LiBH4-LiI and LiBH4-P2S5.

[0083] The shape of the solid electrolyte 111 is not particularly limited and may be needle-shaped, spherical, ellipsoidal, or the like. The shape of the solid electrolyte 111 may also be particulate.

[0084] When the solid electrolyte 111 is particulate (for example, spherical), the median diameter of the solid electrolyte 111 may be 0.1 μm or more and 5 μm or less, or 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) used in the manufacture of the electrode plate 1000 is improved, and it may have a denser structure. When the median diameter of the solid electrolyte 111 is 5 μm or less, the electrode plate 1000 may have high surface smoothness and a denser structure.

[0085] The median diameter refers to the particle size at which the cumulative volume in the volume-based particle size distribution equals 50%. The volume-based particle size distribution is determined by laser diffraction scattering. The same applies to the other materials listed below.

[0086] The specific surface area of ​​solid electrolyte 111 is 0.1 m². 2 / g or more 100m 2 It may be less than / g, 1m 2 / g or more 10m 2 It may be less than / g. The specific surface area of ​​the solid electrolyte 111 is 0.1 m². 2 / g or more 100m 2 If the value is less than / g, the dispersibility of the electrode composition (slurry) used in the manufacture of electrode plate 1000 is improved, and it may have a denser structure. The specific surface area can be measured by the BET multipoint method using a gas adsorption amount measuring device.

[0087] The ionic conductivity of solid electrolyte 111 is 0.01 mS / cm². 2 It may be greater than or equal to 0.1 mS / cm 2 It may be greater than or equal to 1 mS / cm 2 The above is also acceptable. The ionic conductivity of the solid electrolyte 111 is 0.01 mS / cm. 2 In such cases, the output characteristics of the battery can be improved.

[0088] <Active material> The active material 112 includes a material having the property of intercalating and releasing metal ions (e.g., 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.

[0089] The active material 112 includes, for example, a material having the property of intercalating and releasing metal ions (e.g., lithium ions) as a positive electrode active material. Examples of positive electrode active materials include transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, and lithium-containing compounds thereof. Examples of lithium-containing transition metal oxides include Li(NiCoAl)O2, Li(NiCoMn)O2, and LiCoO2. When, for example, a lithium-containing transition metal oxide is used as the positive electrode active material, the manufacturing cost of the electrode plate 1000 can be reduced, and the average discharge voltage of the battery can be improved. Li(NiCoAl)O2 means that Ni, Co, and Al are contained in any ratio. Li(NiCoMn)O2 means that Ni, Co, and Mn are contained in any ratio.

[0090] The median diameter of the positive electrode active material may be between 0.1 μm and 100 μm, or between 1 μm and 10 μm. When the median diameter of the positive 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. This improves the charge and discharge characteristics of the battery. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate within the positive electrode active material improves. Therefore, the battery can operate at high power.

[0091] The active material 112 includes, for example, a material having the property of intercalating and releasing metal ions (e.g., lithium ions) as a negative electrode active material. Examples of negative electrode active materials include metallic materials, carbon materials, oxides, nitrides, tin compounds, and silicon compounds. The metallic material may be a pure metal or an alloy. Examples of metallic materials include lithium metal and lithium alloys. Examples of carbon materials include natural graphite, coke, carbon in the process of graphitization, carbon fibers, spheroidal carbon, artificial graphite, and amorphous carbon. The capacity density of the battery can be improved by using silicon (Si), tin (Sn), silicon compounds, and tin compounds. The safety of the battery can be improved by using oxide compounds containing titanium (Ti) or niobium (Nb).

[0092] The median diameter of the negative electrode active material may be between 0.1 μm and 100 μm, or between 1 μm and 10 μm. 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. This improves the charge and discharge characteristics of the battery. When the median diameter of the negative electrode active material is 100 μm or less, the lithium diffusion rate within the negative electrode active material improves. Therefore, the battery can operate at high power.

[0093] The positive electrode active material and the negative electrode active material may be coated with a coating material to reduce the interfacial resistance between each active material and the solid electrolyte. That is, a coating layer may be provided on the surface 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 used for the coating layer, a material with low electronic conductivity may be used. As the coating material used for the coating layer, oxide materials, oxide solid electrolytes, halide solid electrolytes, sulfide solid electrolytes, etc., may be used. The positive electrode active material and the negative electrode active material may be coated with only one coating material selected from the above materials. That is, the coating layer may be a coating layer formed with only one coating material selected from the above materials. Alternatively, two or more coating layers may be provided using two or more coating materials selected from the above materials.

[0094] Oxide materials used as coating materials for the coating layer include SiO2, Al2O3, TiO2, B2O3, Nb2O5, WO3, and ZrO2.

[0095] As the oxide solid electrolyte used in the coating material of the coating layer, the oxide solid electrolytes exemplified above may be used. For example, Li-Nb-O compounds such as LiNbO3, Li-BO compounds such as LiBO2 and Li3BO3, Li-Al-O compounds such as LiAlO2, Li-Si-O compounds such as Li4SiO4, Li-SO compounds such as Li2SO4, Li4Ti5O 12 Examples include Li-Ti-O compounds such as Li2ZrO3, Li-Zr-O compounds such as Li2MoO3, Li-Mo-O compounds such as LiV2O5, Li-WO compounds such as Li2WO4, and Li-PO compounds such as LiPO4. Oxide solid electrolytes have high potential stability. Therefore, using oxide solid electrolytes as coating materials can further improve the cycle characteristics of batteries.

[0096] As the halide solid electrolyte used in the coating material of the coating layer, the halide solid electrolytes exemplified above may 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 Examples include Li-Ti-Al-F compounds such as F6. Halide solid electrolytes possess high ionic conductivity and high potential stability. Therefore, using halide solid electrolytes as coating materials can further improve the battery's cycle characteristics.

[0097] As the sulfide solid electrolyte used as the coating material for the coating layer, the sulfide solid electrolytes exemplified above may be used. For example, Li-PS compounds such as Li2S-P2S5 can be used. Sulfide solid electrolytes have high ionic conductivity and low Young's modulus. Therefore, by using a sulfide solid electrolyte as the coating material, a uniform coating can be achieved, and the battery's cycle characteristics can be further improved.

[0098] <Second Binder> As described above, the second binder 113 contains a styrene-based elastomer in which the mole fraction of repeating units derived from styrene is 0.12 or more, and the total nitrogen content is 120 ppm by mass or more and 400 ppm by mass or less. With this configuration, a sufficient amount of aromatic rings is present in the electrode layer 110, and the interaction between the conductive carbon 103 and the second binder 113 is stronger, so the peel strength between the electrode layer 110 and the current collector 100 tends to improve. Also, in the case of the current collector 101, if the coating layer 102 covers only a part of the substrate 101, the electrode layer 110 can come into direct contact with the substrate 101. In this case, the electrode layer 110 contains a suitable amount of nitrogen-containing modifying groups, and the interaction with the substrate 101 is stronger over a wider area, so the peel strength between the electrode layer 110 and the current collector 100 tends to improve, and the uniformity of that strength also tends to improve. A styrene-based elastomer means an elastomer that contains repeating units derived from styrene. Repeating units mean molecular structures derived from monomers and are sometimes called constituent units. Styrene-based elastomers are suitable as binders for electrode plates 1000 due to their excellent flexibility and elasticity.

[0099] In styrene-based elastomers, the ratio of the degree of polymerization m of repeating units derived from styrene to the degree of polymerization n of repeating units derived from monomers other than styrene is defined as m:n. In this case, the mole fraction (φ) of repeating units derived from styrene in a styrene-based elastomer can be calculated by φ = m / (m+n). In styrene-based elastomers, the mole fraction (φ) of repeating units derived from styrene can be calculated, for example, by proton nuclear magnetic resonance ( 1This can be determined by 1H-NMR measurement.

[0100] In styrene-based elastomers, the mole fraction (φ) of repeating units derived from styrene is 0.12 or greater. This tends to improve the peel strength between the electrode layer 110 and the current collector 100. The mole fraction (φ) of the styrene-based elastomer may be between 0.12 and 0.55, or between 0.18 and 0.3. A mole fraction (φ) of styrene-based elastomer of 0.12 or greater can improve the strength of the electrode layer 110. A mole fraction (φ) of styrene-based elastomer of 0.55 or less can improve the flexibility of the electrode layer 110.

[0101] The content of repeating units derived from styrene in the styrene-based elastomer may be 20% by mass or more. This tends to improve the peel strength between the electrode layer 110 and the current collector 100. The content of repeating units derived from styrene in the styrene-based elastomer may be 20% by mass or more and 70% by mass or less, or 30% by mass or more and 45% by mass or less. The content of repeating units 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, which can be determined by the method described above. Alternatively, it can be measured by a method using an ultraviolet spectrophotometer.

[0102] The styrene-based elastomer may be a block copolymer comprising a first block composed of repeating units derived from styrene and a second block composed of repeating units derived from a conjugated diene. Examples of conjugated dienes include butadiene and isoprene. The repeating units derived from the conjugated diene may be hydrogenated. That is, the repeating units derived from the conjugated diene may or may not have unsaturated bonds such as carbon-carbon double bonds. The block copolymer may have a triblock arrangement composed of two first blocks and one second block. The block copolymer may be an ABA-type triblock copolymer. In this triblock copolymer, block A corresponds to the first block and block B corresponds to the second block. The first block functions, for example, as a hard segment. The second block functions, for example, as a soft segment.

[0103] Examples of styrene-based elastomers 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 rubber (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and hydrogenated styrene-butadiene rubber (HSBR). The second binder 113 may contain SBR or SEBS as the styrene-based elastomer. A mixture containing two or more selected from these may be used as the second binder 113. Because styrene-based elastomers have excellent flexibility and elasticity, they are suitable as binders for the electrode layer 110.

[0104] Styrene-based elastomers may also be styrene-based triblock copolymers. Examples of styrene-based triblock copolymers 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), and styrene-isoprene-styrene block copolymer (SIS). These styrene-based triblock copolymers are sometimes called styrene-based thermoplastic elastomers. These styrene-based triblock copolymers tend to be flexible and have high strength.

[0105] The styrene-based elastomer may contain styrene-ethylene / butylene-styrene block copolymer (SEBS). SEBS is particularly suitable as a binder for the electrode layer 110 because it has excellent flexibility and elasticity, as well as excellent packing properties during thermal compression.

[0106] The total nitrogen content of the styrene-based elastomer is between 120 ppm by mass and 400 ppm by mass. This tends to improve the peel strength and uniformity between the electrode layer 110 and the current collector 100. The total nitrogen content of the styrene-based elastomer may be between 150 ppm by mass and 300 ppm by mass, or between 190 ppm by mass and 250 ppm by mass. The total nitrogen content can be determined by a trace total nitrogen analyzer. For example, using a trace total nitrogen analyzer (TN-2100H) manufactured by Nitto Seiko Analytech Co., Ltd., the mass (μg) of nitrogen (N) contained in 1 g of polymer is measured using a pyridine / toluene solution as a standard sample. The total nitrogen content is the ratio (μg / g = ppm) of the mass (μg) of nitrogen (N) contained in 1 g of polymer.

[0107] Styrene-based elastomers may contain modifying groups having nitrogen atoms. A modifying group refers to a functional group that chemically modifies all repeating units in a polymer chain, some repeating units in a polymer chain, or the terminal portion of a polymer chain. Modifying groups can be introduced into polymer chains by substitution reactions, addition reactions, etc. Nitrogen-containing modifying groups are nitrogen-containing functional groups, such as amino groups, nitrile groups, and nitro groups. Nitrogen-containing modifying groups can be introduced into polymer chains, for example, by reacting them with a modifying agent. Examples of modifying agent compounds include amine compounds, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen-containing carbonyl compounds, nitrogen-containing vinyl compounds, nitrogen-containing epoxy compounds, and nitrogen-containing alkoxysilicon compounds. The position of the modifying group may be at the end of the polymer chain. Styrene-based elastomers having modifying groups at the ends of polymer chains may have effects similar to those of so-called surfactants. In other words, by using a styrene-based elastomer having a modifying group at the end of the polymer chain, the modifying group is adsorbed onto the solid electrolyte 111, and the polymer chain can suppress aggregation of particles of the solid electrolyte 111. As a result, the dispersibility of the solid electrolyte 111 can be further improved. The styrene-based elastomer may be, for example, a styrene-based elastomer with terminally amine-modified structures. The styrene-based elastomer may also be, for example, a styrene-based elastomer having a nitrogen atom at at least one end of the polymer chain and having a star-shaped polymer structure centered on a nitrogen-containing alkoxysilane substituent.

[0108] Styrene elastomers may have modifying groups containing atoms other than nitrogen, in addition to modifying groups containing nitrogen atoms. Examples of modifying groups containing atoms other than nitrogen include elements with relatively high electronegativity such as O, S, F, Cl, Br, and F, and elements with relatively low electronegativity such as Si, Sn, and P. Such modifying groups can impart polarity to styrene elastomers. Examples of modifying groups include carboxylic acid groups, acid anhydride groups, acyl groups, hydroxyl groups, sulfo groups, sulfanyl groups, phosphoric acid groups, phosphonic acid groups, isocyanate groups, epoxy groups, and silyl groups. A specific example of an acid anhydride group is the maleic anhydride group. Modifying groups may also be functional groups that can be introduced by reacting them with modifying agents containing the following compounds. Examples of modifying agent compounds include epoxy compounds, ether compounds, ester compounds, mercapto group derivatives, thiocarbonyl compounds, silicon halide compounds, silicon epoxidized compounds, silicon vinylide compounds, alkoxysilicon compounds, tin halide compounds, organotin carboxylate compounds, phosphite ester compounds, and phosphino compounds. When the styrene-based elastomer contains the above-mentioned modifying groups, the interaction with the current collector 100 can improve the peel strength between the electrode layer 110 and the current collector 100.

[0109] The styrene elastomer may be a mixture of two or more styrene elastomers having different total nitrogen content for the purpose of adjusting the total nitrogen content. A styrene elastomer with a relatively high total nitrogen content may be mixed with an unmodified styrene elastomer.

[0110] Weight-average molecular weight (M) of styrene-based elastomers wThe weight-average molecular weight 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, 500,000 or more, 800,000 or more, or 1,000,000 or more. The upper limit of the weight-average molecular weight is, for example, 1,500,000. By having a weight-average molecular weight of 200,000 or more for the styrene-based elastomer, the particles of the solid electrolyte 111 and the active material 112 can adhere to each other with sufficient adhesive strength. By having a weight-average molecular weight of 1,500,000 or less for the styrene-based elastomer, ion conduction between the particles of the solid electrolyte 111 is less likely to be inhibited 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 GPC measurements, chloroform may be used as the eluent. If two or more peak tops are observed in the chart obtained by GPC measurement, the weight-average molecular weight calculated from the overall peak range including each peak top can be considered as the weight-average molecular weight of the styrene-based elastomer.

[0111] The second binder 113 may contain a binder other than a styrene-based elastomer. Alternatively, the second binder 113 may be a styrene-based elastomer. In other words, the second binder 113 may contain only a styrene-based elastomer.

[0112] <Electrode layer> The electrode layer 110 contains a second binder 113. The electrode layer 110 may further contain a solid electrolyte 111, an active material 112, or both. This configuration improves the ionic conductivity inside the electrode layer 110 while maintaining sufficient strength, enabling the battery to operate at high power.

[0113] 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. This allows the solid electrolyte 111 and the active material 112 to be well dispersed.

[0114] In the electrode layer 110, the volume ratio "v1:100-v1" of the active material 112 to the solid electrolyte 111 may satisfy the condition 30 ≤ v1 ≤ 95. v1 represents the volume ratio of the active material 112 when the total volume of the active material 112 and solid electrolyte 111 contained in the electrode layer 110 is set to 100. When 30 ≤ v1 is satisfied, it is easier to ensure a sufficient energy density for the battery. When v1 ≤ 95 is satisfied, it is easier to operate the battery at high power.

[0115] The thickness of the electrode layer 110 may be between 10 μm and 500 μm. When the thickness of the electrode layer 110 is 10 μm or more, a sufficient energy density can be easily ensured for the battery. When the thickness of the electrode layer 110 is 500 μm or less, the battery can be operated at a higher power output more easily.

[0116] In the electrode layer 110, the ratio of the second binder 113 to the solid electrolyte 111 may be 0.1% by mass or more and 10% by mass or less, 0.5% by mass or more and 8% by mass or less, or 1% by mass or more and 5% by mass or less. When the ratio of the second binder 113 to the solid electrolyte 111 is 0.1% by mass or more, the second binder 113 tends to cause more solid electrolyte 111 particles to bind together. This can improve the film strength of the electrode layer 110. When the ratio of the second binder 113 to the solid electrolyte 111 is 10% by mass or less, the contact between solid electrolyte 111 particles in the electrode layer 110 tends to improve. This can improve the ionic conductivity of the electrode layer 110.

[0117] In the electrode layer 110, the ratio of the second binder 113 to the active material 112 may be 0.03% by mass or more and 4% by mass or less, 0.15% by mass or more and 2% by mass or less, or 0.3% by mass or more and 1% by mass or less. When the ratio of the second binder 113 to the active material 112 is 0.03% by mass or more, the second binder 113 tends to cause more active material 112 particles to bind together. This can improve the film strength of the electrode layer 110. When the ratio of the second binder 113 to the active material 112 is 4% by mass or less, the contact between active material 112 particles in the electrode layer 110 tends to improve. This can improve the output characteristics of the battery.

[0118] The electrode layer 110 may further contain a conductive additive for the purpose of improving electronic conductivity. Examples of conductive additives include graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black and Ketjenblack, conductive fibers such as carbon fibers and metal fibers, conductive powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene. Using carbon materials as conductive additives can reduce costs.

[0119] The electrode layer 110 may contain a dispersant to improve the dispersibility of the solid electrolyte 111 and the active material 112. The dispersant may be a low-molecular-weight dispersant or a high-molecular-weight dispersant. As the dispersant, for example, commercially available dispersants, wetting agents, or surfactants may be used.

[0120] 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. Examples of amine compounds include aliphatic amines such as methylamine and dimethylamine, aromatic amines such as aniline, and heterocyclic amines such as imidazole and imidazoline.

[0121] In the electrode layer 110, the dispersant may contain imidazoline or an imidazoline derivative. Imidazolin or an imidazoline derivative is suitable because it improves the dispersibility of the solid electrolyte 111. Examples of imidazoline derivatives include 1-hydroxyethyl-2-alkenylimidazoline.

[0122] 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, and may be, for example, 0.001% by mass or more and 10% by mass or less, or 0.01% by mass or more and 1.0% by mass or less. When the ratio of the mass of the dispersant is 0.001% by 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% by mass or less, the decrease in the ionic conductivity of the solid electrolyte 111 can be suppressed.

[0123] [Method for manufacturing electrode plates] The electrode plate 1000 can be manufactured, for example, by the following method. First, an electrode composition is prepared containing a solid electrolyte 111, an active material 112, and a second binder 113 for forming the electrode layer 110. 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 may be used. As the solvent, a solvent that does not react with the solid electrolyte 111, such as an aromatic hydrocarbon solvent such as tetralin, may be used. Next, the electrode composition is applied onto the coating layer 102 of the current collector 100. Methods for applying the electrode composition include die coating, gravure coating, doctor blade coating, bar coating, spray coating, and electrostatic coating. By drying the obtained coating film, the electrode layer 110 is formed and the electrode plate 1000 can be obtained. The method for drying the coating film is not particularly limited. For example, the coating film may be dried by heating it with warm air or hot air drying at a set temperature of 80°C to 150°C. The method of preparing the electrode layer 110 by applying the electrode composition onto the coating layer 102 is sometimes called a wet coating method.

[0124] [Method for measuring the peel strength of electrode plates] The peel strength between the electrode layer 110 and the current collector 100 can be measured in a dry room with a dew point of -50°C or lower using a universal material testing machine (A&D Corporation, RTH-1310) by the following method. First, an electrode plate 1000 cut to a width of 15 mm is bonded to the test plate with double-sided tape. Specifically, the electrode layer 110 of the electrode plate 1000 is attached to the test plate via the double-sided tape. Next, using a testing machine equipped with a jig for a 90° peel test of adhesive 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, the measurement values ​​for the first 10 mm to 12 mm of the electrode layer 110 peeled from the current collector 100 after the start of measurement are not used, and the measurement values ​​(unit: N) for the subsequent 5 mm of the electrode layer 110 peeled from the current collector 100 are recorded continuously. The average value (Av) obtained by dividing this measurement by the width of the electrode plate 1000 can be considered as the peel strength (unit: N / m) between the electrode layer 110 and the current collector 100 on the electrode plate 1000. Furthermore, the standard deviation (σ) obtained by dividing the measurement by the width of the electrode plate 1000 can be calculated, and the value obtained by dividing the standard deviation (σ) by the average value (Av) can be considered as the coefficient of variation. Here, the coefficient of variation represents the variability of the peel strength. The lower the coefficient of variation, the higher the uniformity of the peel strength.

[0125] Figure 2 is a cross-sectional view of an electrode plate 1100 according to a modified example. The electrode plate 1100 comprises 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 has a stripe shape 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 the configuration of the electrode plate 1000 described earlier. The electrode plate 1100 can be used in place of the electrode plate 1000.

[0126] (Embodiment 2) Figure 3 is a cross-sectional view of the battery 2000 according to Embodiment 2. The battery 2000 comprises a negative electrode 201, a positive electrode 203, and an electrolyte layer 202.

[0127] At least one selected from the group consisting of a negative electrode 201 and a positive electrode 203 includes the electrode plate 1000 in Embodiment 1. That is, at least one selected from the group consisting of a negative electrode 201 and a positive electrode 203 comprises an electrode layer 110 and a current collector 100.

[0128] The electrolyte layer 202 is located between the negative electrode 201 and the positive electrode 203.

[0129] 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, a battery 2000 using an electrode plate 1000 having such an electrode layer 110 and current collector 100 has excellent cycle characteristics. Furthermore, the output characteristics of the battery 2000 can also be improved.

[0130] As shown in Figure 3, in the battery 2000, the negative electrode 201 may be the electrode plate 1000 in Embodiment 1. In this case, the negative electrode 201 comprises the electrode layer 110 and current collector 100 described in Embodiment 1. Below, a 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 form. In the battery 2000, the positive electrode 203 may be the electrode plate 1000 in Embodiment 1 described above.

[0131] With the above configuration, the output characteristics of the 2000 battery can be further improved.

[0132] The electrolyte layer 202 is a layer containing an electrolyte material. Examples of the electrolyte material include solid electrolytes. That is, the electrolyte layer 202 may be a solid electrolyte layer. As the solid electrolyte contained in the electrolyte layer 202, the solid electrolytes exemplified as solid electrolyte 111 may be used, such as sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, polymer solid electrolytes, and complex hydride solid electrolytes.

[0133] The electrolyte layer 202 may contain a solid electrolyte as its main component. The electrolyte layer 202 may contain a solid electrolyte in an amount of 70% or more (70% by mass or more) by mass relative to the total electrolyte layer 202.

[0134] With the above configuration, the charge and discharge characteristics of the battery 2000 can be improved.

[0135] The electrolyte layer 202 mainly contains a solid electrolyte, and may also contain unavoidable impurities, or starting materials, by-products, and decomposition products used when synthesizing the solid electrolyte.

[0136] The electrolyte layer 202 may contain 100% (100 mass%) of solid electrolyte in terms of mass relative to the total electrolyte layer 202, excluding impurities that are unavoidable to be present.

[0137] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0138] 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.

[0139] The thickness of the electrolyte layer 202 may be between 1 μm and 300 μm. When the thickness of the electrolyte layer 202 is 1 μm or more, the possibility of a 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 be easily operated at high power. In other words, 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 be operated at high power.

[0140] The shape of the solid electrolyte contained in battery 2000 is not particularly limited. The solid electrolyte may be needle-shaped, spherical, ellipsoidal, or the like. The solid electrolyte may also be particulate.

[0141] The positive electrode 203 may contain an electrolyte material, for example, a solid electrolyte. As the solid electrolyte, the solid electrolyte exemplified as the material constituting the electrolyte layer 202 can be used. With the above configuration, the ion conductivity (e.g., lithium ion conductivity) inside the positive electrode 203 is improved, and the battery 2000 can be operated at high power.

[0142] The positive electrode 203 includes, for example, a material having the property of intercalating and releasing metal ions (e.g., lithium ions) as the positive electrode active material. The material exemplified in Embodiment 1 described above may be used as the positive electrode active material.

[0143] The median diameter of the positive electrode active material may be between 0.1 μm and 100 μm. When the median diameter of the positive electrode active material is 0.1 μm or more, the positive electrode active material and the solid electrolyte can be well dispersed in the positive electrode 203. This improves the charge and discharge characteristics of the battery 2000. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate within the positive electrode active material improves. Therefore, the battery 2000 can operate at high power.

[0144] The median diameter of the positive electrode active material may be larger than the median diameter of the solid electrolyte. This allows for good dispersion of the solid electrolyte and the positive electrode active material.

[0145] In the positive electrode 203, the volume ratio of the positive electrode active material to the solid electrolyte "v2:100-v2" may satisfy the condition 30≦v2≦95. v2 represents the volume ratio of the positive electrode active material when the total volume of the positive electrode active material and solid electrolyte contained in the positive electrode 203 is set to 100. If 30≦v2 is satisfied, it is easier to ensure a sufficient energy density for the battery 2000. If v2≦95 is satisfied, it is easier to operate the battery 2000 at a high power output.

[0146] The thickness of the positive electrode 203 may be between 10 μm and 500 μm. When the thickness of the positive electrode 203 is 10 μm or more, a sufficient energy density can be easily ensured for the battery 2000. When the thickness of the positive electrode 203 is 500 μm or less, the battery 2000 can be operated at a higher power output more easily.

[0147] The positive electrode active material may be coated with a coating material to reduce interfacial resistance with the solid electrolyte. A material with low electronic conductivity may be used as the coating material. Examples of coating materials include oxide materials and oxide solid electrolytes. The materials exemplified in Embodiment 1 may also be used as the coating material.

[0148] At least one selected from the group consisting of the electrolyte layer 202 and the positive electrode 203 may contain a binder for the purpose of improving the adhesion between particles. As the binder, the materials exemplified in Embodiment 1 may be used. The binder may be used alone or in combination of two or more.

[0149] As a binder, an elastomer may be used from the viewpoint of excellent binding properties. An elastomer means an elastic polymer. The elastomer used as a binder may be a thermoplastic elastomer or a thermosetting elastomer. The binder may contain a thermoplastic elastomer. As the elastomer, the materials exemplified in Embodiment 1 may be used. When the binder contains an elastomer, for example, high filling of the electrolyte layer 202 or the positive electrode 203 can be achieved by thermal compression when manufacturing the battery 2000.

[0150] At least one selected from the group consisting of 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 for the purpose of facilitating the transfer of lithium ions and improving the output characteristics of the battery 2000.

[0151] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent. Possible non-aqueous solvents include cyclic carbonate solvents, linear carbonate solvents, cyclic ether solvents, linear ether solvents, cyclic ester solvents, linear ester solvents, and fluorine solvents. Examples of cyclic carbonate solvents include ethylene carbonate, propylene carbonate, and butylene carbonate. Examples of linear carbonate solvents include dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. Examples of cyclic ether solvents include tetrahydrofuran, 1,4-dioxane, and 1,3-dioxolane. Examples of linear ether solvents include 1,2-dimethoxyethane and 1,2-diethoxyethane. Examples of cyclic ester solvents include γ-butyrolactone. Examples of linear ester solvents include methyl acetate. Examples of fluorinated solvents include fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, and fluorodimethylene carbonate. As the non-aqueous solvent, one non-aqueous solvent selected from these may be used alone, or a mixture of two or more non-aqueous solvents selected from these may be used.

[0152] The non-aqueous electrolyte may contain at least one fluorine solvent selected from the group consisting of fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, and fluorodimethylene carbonate.

[0153] Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. One lithium salt selected from these may be used alone, or a mixture of two or more lithium salts selected from these may be used. The concentration of the lithium salt in the non-aqueous electrolyte may be between 0.5 mol / liter and 2 mol / liter.

[0154] As a gel electrolyte, a material in which a non-aqueous electrolyte is contained in a polymer material can be used. Examples of the polymer material include polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, and a polymer having an ethylene oxide bond.

[0155] The cation constituting the ionic liquid may be an aliphatic chain quaternary cation such as tetraalkylammonium or tetraalkylphosphonium, an aliphatic cyclic ammonium such as pyrrolidinium, morpholinium, imidazolinium, tetrahydropyrimidinium, piperazinium, or piperidinium, or a nitrogen-containing heteroaromatic cation such as pyridinium or imidazolium. The anion constituting the ionic liquid is PF6 - 、BF4 - 、SbF6 - 、AsF6 - 、SO3CF3 - 、N(SO2F)2 - 、N(SO2CF3)2 - 、N(SO2C2F5)2 - 、N(SO2CF3)(SO2C4F9) - 、C(SO2CF3)3 - and the like. The ionic liquid may contain a lithium salt.

[0156] At least one selected from the group consisting of the electrode layer 110 of the negative electrode 201 and the positive electrode 203 may contain a conductive assistant for the purpose of improving electron conductivity. As the conductive assistant, the materials exemplified in Embodiment 1 can be used.

[0157] At least one selected from the group consisting of the electrode layer 110 of the negative electrode 201 and the positive electrode 203 may contain a dispersant for the purpose of improving the dispersibility of the solid electrolyte and the active material. As the dispersant, the materials exemplified in Embodiment 1 can be used.

[0158] The shapes of the 2000 battery include coin-type, cylindrical, rectangular, sheet-type, button-type, flat, and stacked types.

[0159] 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. Using these, a laminate is fabricated in which the negative electrode 201, the electrolyte layer 202, and the positive electrode 203 are arranged in that order, using a known method. This allows the battery 2000 to be manufactured.

[0160] Figure 4 is a cross-sectional view of a modified battery 2001. Battery 2001 may be a laminate of multiple batteries 2000. Battery 2001 may be manufactured by the following method. A negative electrode (first negative electrode 211), a first electrolyte layer 212, and a first positive electrode 213 are arranged in this order on a current collector 100 on which coating layers 102 are arranged on both sides of a substrate 101. On the other hand, an electrode layer 110 (second negative electrode 221), a second electrolyte layer 222, and a second positive electrode 223 are arranged in this order on the side of the current collector 100 opposite to the side on which the first negative electrode 211 is laminated. This results in a laminate in which the first positive electrode 213, first electrolyte layer 212, first negative electrode 211, current collector 100, second negative electrode 221, second electrolyte layer 222, and second positive electrode 223 are arranged in this order. The laminate may be manufactured by press molding at a high temperature using a press machine, for example, at a temperature of 120°C to 195°C, to produce the battery 2001. This method makes it possible to manufacture a laminate of two batteries 2000 while suppressing warping of the battery, and to manufacture high-output batteries 2001 more efficiently. In manufacturing the battery 2001, the order in which each component is laminated is not particularly limited. For example, after placing the first negative electrode 211 and the second negative electrode 221 on the current collector 100, the first electrolyte layer 212, the second electrolyte layer 222, the first positive electrode 213, and the second positive electrode 223 may be laminated in this order to produce a laminate of two batteries 2000. Furthermore, multiple batteries 2001 and positive electrode current collectors may be prepared, and the battery 2001 and positive electrode current collectors may be laminated alternately to produce a laminate of batteries 2000. By this method, batteries 2000 can be laminated with high efficiency.

[0161] (Other embodiments) (Note) The above description of embodiments discloses the following technologies.

[0162] (Technology 1) A current collector having a substrate and a coating layer covering the substrate, An electrode layer arranged on the current collector, Equipped with, The coating layer comprises conductive carbon and a first binder. The electrode layer includes a second binder, The second binder contains a styrene-based elastomer having a mole fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 ppm by mass or more and 400 ppm by mass or less. Electrode plate.

[0163] With this configuration, not only can the peeling strength between the electrode layer and the current collector be improved, but the uniformity of the peeling strength can also be improved.

[0164] (Technology 2) The electrode plate according to Technology 1, wherein the first binder contains polyimide. Polyimide tends to exhibit higher heat resistance. Therefore, even if the component including the current collector is compressed at high temperatures, the coating layer is less likely to adhere to production equipment such as a press machine. As a result, the productivity of electrochemical devices is improved.

[0165] (Technology 3) The substrate is an electrode plate according to Art 1 or 2, comprising aluminum or an aluminum alloy. Such a configuration can not only improve the peel strength between the electrode layer and the current collector, but also improve the mass energy density of the electrochemical device.

[0166] (Technology 4) An electrode plate according to any one of the art claims 1 to 3, wherein the electrode layer further comprises a solid electrolyte. The electrode plate of this disclosure is suitable for electrochemical devices, particularly batteries, in which the electrode layer contains a solid electrolyte.

[0167] (Technology 5) The electrode plate according to Technology 4, wherein the solid electrolyte includes a sulfide solid electrolyte. The sulfide solid electrolyte is particularly suitable as a solid electrolyte for the electrode layer because it has superior ionic conductivity and moldability.

[0168] (Technology 6) Positive electrode and, The negative electrode and, An electrolyte layer located between the positive electrode and the negative electrode, Equipped with, At least one selected from the group consisting of the positive electrode and the negative electrode includes an electrode plate according to any one of the art claims 1 to 5. battery.

[0169] Because the peeling strength between the electrode layer and the current collector is high, and the uniformity of the peeling strength is also high, batteries using electrode plates having such electrode layers and current collectors have excellent cycle characteristics. [Examples]

[0170] The details of this disclosure will be explained below using examples and comparative examples. However, the current collectors, electrode plates, and batteries of this disclosure are not limited to the following examples.

[0171] <Example 1> [Current collector fabrication] A paint was prepared by kneading conductive carbon, a first binder, and a solvent. Carbon black and graphite were used as the conductive carbon. Polyvinylidene fluoride, a non-aromatic super engineering plastic, was used as the first binder. Next, the paint was applied to one side of an aluminum alloy foil (A3003 foil, thickness: 15 μm) to form a coating film. The coating film was dried at 165°C to form a coating layer. Furthermore, the paint was applied to the other side of the aluminum alloy foil to form a coating film. The coating film was dried at 165°C to form a coating layer. This created a current collector having coating layers on both sides. In the current collector of Example 1, the mass per unit area of ​​the coating layer was 0.94 g / m². 2 That was the case.

[0172] [solvent] In all of the following steps, commercially available dehydrating solvents or solvents dehydrated by nitrogen bubbling were used as the solvent. The water content in the solvent was 10 ppm by mass or less.

[0173] [Preparation of the second binder solution] A 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 between 5% by mass and 10% by mass.

[0174] Tetralin was used as the solvent for the second binder solution. As the styrene-based elastomer constituting the second binder, a mixture containing hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, ToughTec MP10) and hydrogenated block copolymer (SEBS, manufactured by Kraton, G1633) in a mass ratio of 1:1 was used. "ToughTec" is a registered trademark of Asahi Kasei Corporation.

[0175] [Measurement of mole fraction of repeating units derived from styrene] The mole fraction of repeating units derived from styrene in styrene-based elastomers was determined by the following method. First, the sample containing the styrene-based elastomer was subjected to proton nuclear magnetic resonance (CONT) using a nuclear magnetic resonance spectrometer (Bruker AVANCE500). 1 ¹H-NMR (H-NMR) measurements were performed. The sample used for measurement was a styrene-based elastomer dissolved in CDCl3. The CDCl3 contained 0.05% tetramethylsilane (TMS). 1 ¹H-NMR measurements were performed under conditions of a resonance frequency of 500 MHz and a measurement temperature of 23°C. From the obtained NMR spectra, the integral values ​​of peaks originating from the styrene skeleton and the integral values ​​of peaks originating from other skeletons were identified. Using the identified integral values, the mole fraction of repeating units originating from styrene in the styrene-based elastomer was determined.

[0176] [Measurement of weight-average molecular weight] Gel permeation chromatography (GPC) measurements using a high-speed GPC instrument (HLC-832-GPC, manufactured by Tosoh Corporation) were used to determine the weight-average molecular weight (M) of the styrene-based elastomer constituting the second binder. wThe weight-average molecular weight (M) of the styrene elastomer was measured. The sample used for measurement was a styrene elastomer dissolved in chloroform and filtered using a 0.2 μm pore size filter. Two SuperHM-H columns manufactured by Tosoh Corporation were used. A differential refractometer was used for GPC measurement. GPC measurement was performed under conditions of a flow rate of 0.6 mL / min and a column temperature of 40°C. Monodisperse polystyrene (Tosoh Corporation) was used as the standard sample. The weight-average molecular weight (M) of the styrene elastomer was determined by GPC measurement. w ) was identified.

[0177] [Fabrication of electrode plates] In an argon glove box with a dew point of -60°C or lower, tetralin and a second binder solution were added to Li2S-P2S5 glass ceramics (hereinafter referred to as "LPS"). These materials were mixed in a mass ratio of LPS:second binder = 100:3, and adjusted to a solid content concentration (NV) of 47. Next, the resulting mixture was homogenized and mixed under high shear using a homogenizer (AS ONE, HG-200) and a generator (AS ONE, K-20S) to prepare a slurry. Then, the slurry was applied to the coating layer of the current collector, and the resulting coating film was dried in a vacuum atmosphere at 100°C for 1 hour to produce the electrode plate of Example 1.

[0178] <Example 2> The electrode plate of Example 2 was prepared 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, ToughTec MP10) and a hydrogenated block copolymer (SEBS, manufactured by Kraton, 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.

[0179] <Example 3> The electrode plate of Example 3 was fabricated in the same manner as in Example 1, except that a soluble polyimide, an aromatic super engineering plastic, was used as the first binder. In the current collector of Example 3, the mass per unit area of ​​the coating layer was 1.3 g / m². 2 That was the case.

[0180] <Example 4> The electrode plate of Example 4 was fabricated in the same manner as in Example 2, except that a soluble polyimide was used as the first binder. In the current collector of Example 4, the mass per unit area of ​​the coating layer was 1.3 g / m². 2 That was the case.

[0181] <Comparative Example 1> The electrode plate of Comparative Example 1 was manufactured in the same manner as in Example 1, except that a coating layer was not provided on the current collector.

[0182] <Comparative Example 2> The electrode plate of Comparative Example 2 was manufactured in the same manner as in Example 2, except that a coating layer was not provided on the current collector.

[0183] <Comparative Example 3> The electrode plate of Comparative Example 3 was prepared 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, ToughTec MP10) and a hydrogenated block copolymer (SEBS, manufactured by Kraton, 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.

[0184] <Comparative Example 4> The electrode plate of Comparative Example 4 was prepared 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, ToughTec MP10) and a hydrogenated block copolymer (SEBS, manufactured by Kraton, 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.

[0185] <Comparative Example 5> The electrode plate of Comparative Example 5 was prepared by the same method as in Example 1, except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei Corporation, Asaprene Y031) was used as the styrene-based elastomer constituting the second binder. "Asaprene" is a registered trademark of Asahi Kasei Corporation.

[0186] <Comparative Example 6> The electrode plate of Comparative Example 6 was prepared 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 styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 43.

[0187] [Peel test] The peel strength and coefficient of variation of the electrode plates of the examples and comparative examples were measured using the method described above. The results are shown in Table 1. The peel strength was measured three times for each electrode plate. The "peel strength" and "coefficient of variation" shown in Table 1 are the average values ​​obtained from the three measurements.

[0188] [Table 1]

[0189] The current collectors of the electrode plates in Comparative Example 1 and Comparative Example 2 did not have a coating layer. Therefore, the peel strength of the electrode plates in Comparative Example 1 and Comparative Example 2 was low.

[0190] In the electrode plates of Comparative Examples 4 and 5, the total nitrogen content of the second binder in the electrode layer was low, at 106 ppm and 107 ppm, respectively. Therefore, the peel strength of the electrode plates of Comparative Examples 4 and 5 was low. In the electrode plate of Comparative Example 6, the mole fraction of repeating units derived from styrene in the second binder of the electrode layer was low, at 0.09. Therefore, the peel strength of the electrode plate of Comparative Example 6 was low.

[0191] In the electrode plate of Comparative Example 3, the total nitrogen content of the second binder in the electrode layer was 446 ppm. Although the electrode plate of Comparative Example 3 showed high peel strength, its coefficient of variation was large. In other words, there was a large variation in peel strength.

[0192] From the results shown in Table 1, it can be understood that the mole fraction of repeating units derived from styrene in the second binder of the electrode layer, and the total nitrogen content of the second binder of the electrode layer, correlate with the peel strength and its coefficient of variation. In the electrode plates of Examples 1 to 4, which contained a styrene-based elastomer in which the mole fraction of repeating units derived from styrene was 0.12 or higher and the total nitrogen content was 120 ppm to 400 ppm, the peel strength between the electrode layer and the current collector was high, and the coefficient of variation of the peel strength was low.

[0193] Figure 5A is a graph obtained from the peel test of the electrode plate in Example 1. Figure 5B is a graph obtained from the peel test of the electrode plate in Comparative Example 3. The horizontal axis represents the amount of movement of the jig (mm). In other words, the horizontal axis corresponds to the position of the peeled electrode layer. The vertical axis represents the measured peel strength (N / m). For the calculation of the peel strength and coefficient of variation in Example 1, data in the range of movement from 12 mm to 17 mm was used. For the calculation of the peel strength and coefficient of variation in Comparative Example 3, data in the range of movement from 11 mm to 16 mm was used. The reason for this is that by selecting a stable range after the unstable range at the beginning of peeling, it is possible to minimize the variability of the data, which is thought to lead to the accurate calculation of the peel strength and coefficient of variation.

[0194] As shown in Figure 5B, the variation in peel strength of the electrode plate in Comparative Example 3 was large. In contrast, as shown in Figure 5A, the variation in peel strength of the electrode plate in Example 1 was small. Thus, according to the technology of this disclosure, not only is the peel strength between the electrode layer and the current collector improved, but its uniformity is also improved. [Industrial applicability]

[0195] The electrode plates of this disclosure can be used in electrochemical devices such as batteries and capacitors. [Explanation of Symbols]

[0196] 100,100a current collector 101 circuit board 102,102a Covering layer 103 Conductive carbon 104 Binder 1 110 Electrode layer 111 Solid electrolyte 112 Active material 113 Second Binder 201 Negative electrode 202 Electrolyte layer 203 Positive electrode 211 First negative electrode 212 1st electrolyte layer 213 First positive electrode 221 Second Negative Electrode 222 Second electrolyte layer 223 Second positive electrode 1000,1100 electrode plate 2000 batteries 2001 battery

Claims

1. A current collector having a substrate and a coating layer covering the substrate, An electrode layer arranged on the current collector, Equipped with, The coating layer comprises conductive carbon and a first binder. The electrode layer includes a second binder, The second binder contains a styrene-based elastomer having a mole fraction of repeating units derived from styrene of 0.12 or more, and a total nitrogen content of 120 ppm by mass or more and 400 ppm by mass or less. electrode plate.

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

3. The substrate includes aluminum or an aluminum alloy. The electrode plate according to claim 1.

4. The electrode layer further comprises a solid electrolyte. The electrode plate according to claim 1.

5. The solid electrolyte includes a sulfide solid electrolyte. The electrode plate according to claim 4.

6. Positive electrode and, The negative electrode and, An electrolyte layer located between the positive electrode and the negative electrode, Equipped with, At least one selected from the group consisting of the positive electrode and the negative electrode includes the electrode plate described in claim 1, battery.

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