阅读说明：本技术 全固体电池 (All-solid-state battery ) 是由 大浦庆 于 2019-05-24 设计创作，主要内容包括：提供一种提高了电极体与密封部的密合性的全固体电池。通过本发明的一方式,提供一种全固体电池,具备层叠电极体和密封部,上述层叠电极体具有电极合剂层和固体电解质层层叠而成的结构部分,上述密封部覆盖上述层叠电极体的层叠端面。上述电极合剂层包含活性物质和粘合剂树脂。上述密封部包含密封树脂和绝缘粒子。上述电极合剂层所含的上述粘合剂树脂的溶解度参数与上述密封部所含的上述密封树脂的溶解度参数之差的绝对值为1.9(cal/cm<Sup>3</Sup>)<Sup>0.5</Sup>以下。(The present invention provides an all-solid battery having improved adhesion between an electrode assembly and a sealing part, wherein the all-solid battery comprises a laminated electrode assembly having a structural portion in which an electrode material mixture layer and a solid electrolyte layer are laminated, and a sealing part covering a laminated end face of the laminated electrode assembly, wherein the electrode material mixture layer contains an active material and a binder resin, and the sealing part contains a sealing resin and insulating particles, and wherein the absolute value of the difference between the solubility parameter of the binder resin contained in the electrode material mixture layer and the solubility parameter of the sealing resin contained in the sealing part is 1.9(cal/cm 3 ) 0.5 or less.)

1. An all-solid battery includes a laminated electrode body having a structure portion in which an electrode material mixture layer and a solid electrolyte layer are laminated, and a sealing portion that covers at least a lamination end face of the laminated electrode body,

The electrode material mixture layer contains an active material and a binder resin,

The sealing portion contains a sealing resin and insulating particles,

An absolute value of a difference between a solubility parameter of the binder resin contained in the electrode material mixture layer and a solubility parameter of the sealing resin contained in the sealing portion is 1.9(cal/cm ³) ^0.5 or less.

2. The all-solid battery according to claim 1,

The adhesive resin and the sealing resin comprise the same resin.

3. The all-solid battery according to claim 2,

The adhesive resin and the sealing resin each contain rubber.

4. The all-solid battery according to any one of claims 1 to 3,

The electrode material mixture layer contains a Si-based material as the active material.

5. the all-solid battery according to any one of claims 1 to 4,

The solubility parameter of the binder resin contained in the electrode material mixture layer is 7(cal/cm ³) ^0.5 or more and 9(cal/cm ³) ^0.5 or less.

6. The all-solid battery according to any one of claims 1 to 5,

The solubility parameter of the sealing resin contained in the sealing part is 7(cal/cm ³) ^0.5 or more and 11(cal/cm ³) ^0.5 or less.

7. The all-solid battery according to any one of claims 1 to 6,

The electrode mixture layer includes a positive electrode mixture layer and a negative electrode mixture layer,

An absolute value of a difference between a solubility parameter of the binder resin contained in the positive electrode mixture layer and a solubility parameter of the sealing resin contained in the sealing portion is 1.9(cal/cm ³) ^0.5 or less, and,

An absolute value of a difference between a solubility parameter of the binder resin contained in the negative electrode mixture layer and a solubility parameter of the sealing resin contained in the sealing portion is 1.9(cal/cm ³) ^0.5 or less.

8. The all-solid battery according to any one of claims 1 to 7,

The solid electrolyte layer contains a solid electrolyte material and a binder resin,

An absolute value of a difference between a solubility parameter of the binder resin contained in the solid electrolyte layer and a solubility parameter of the sealing resin contained in the sealing portion is 1.9(cal/cm ³) ^0.5 or less.

Technical Field

the present invention relates to an all-solid battery.

Background

Conventionally, a technique for improving the water resistance and durability of a lithium battery is known. For example, japanese patent application laid-open No. 2005-5163 discloses a battery including a bipolar electrode in which a positive electrode active material layer is formed on one surface of a current collector and a negative electrode active material layer is formed on the other surface. In this battery, the entire periphery of an electrode body in which a plurality of bipolar electrodes and an electrolyte layer are laminated is covered with a resin, and a sealing portion is provided around the electrode body.

disclosure of Invention

however, according to the studies of the present inventors, it is considered that the above-described technology still has room for improvement if, for example, long-term durability is taken into consideration. For example, a battery mounted on a vehicle intermittently repeats random low-frequency vibrations due to vibrations of a driving system or a traveling vehicle, for example. In addition, with rapid charge and discharge of the battery, the electrode body may expand and contract greatly in a moment. As a result, the sealing portion is peeled off from the electrode body, and the technical effect is not sustained.

The present invention has been made in view of the above, and an object thereof is to provide an all-solid-state battery in which adhesion between an electrode body and a sealing portion is improved.

According to one aspect of the present invention, there is provided an all-solid battery including a laminated electrode body having a structural portion in which an electrode material mixture layer and a solid electrolyte layer are laminated, and a sealing portion that covers at least a laminated end face of the laminated electrode body, the electrode material mixture layer including an active material and a binder resin, the sealing portion including a sealing resin and insulating particles, wherein an absolute value of a difference between a solubility parameter of the binder resin included in the electrode material mixture layer and a solubility parameter of the sealing resin included in the sealing portion is 1.9(cal/cm ³) ^0.5 or less.

In the all-solid-state battery, the difference in solubility parameter between the binder resin and the sealing resin is suppressed to a predetermined value or less, and the compatibility between the binder resin and the sealing resin is improved. In the all-solid-state battery, the adhesion and the integrity of the laminated electrode body and the sealing portion are thereby improved. In the all-solid-state battery, the sealing portion contains the insulating particles, so that the mechanical strength of the sealing portion is improved. By the above action, even when external force such as vibration is repeatedly applied to the all-solid-state battery, for example, peeling of the sealing portion from the laminated electrode body is less likely to occur, and the technical effects disclosed herein can be maintained for a long period of time.

In the present specification, the Solubility Parameter (Solubility Parameter: SP value) is a Solubility Parameter calculated by the Fedors method, and in the following description, the Solubility Parameter is simply referred to as "SP value". SP value is a value specific to each substance, and the SI unit of the SP value is (J/cm ³) ^0.5 or (MPa) ^0.5, but in the present specification, a conventionally-used (cal/cm ³) ^0.5 unit of the SP value can be converted by the following formula, 1(cal/cm ³) ^0.5 ≈ 2.05(J/cm ³) ^0.5 ≈ 2.05(MPa) ^0.5.

In one embodiment of the present invention, the binder resin and the sealing resin include the same resin. This can improve the adhesion and integrity between the laminated electrode assembly and the sealing part, and can achieve the technical effects disclosed herein at a higher level.

In one aspect of the present invention, the adhesive resin and the sealing resin each contain rubber. In general, the volume change of rubber upon deformation is extremely small. Therefore, by including rubber, the adhesion and the integrity of the laminated electrode assembly to the sealing portion can be improved more effectively.

In one embodiment of the present invention, the electrode material mixture layer contains a Si-based material as the active material. In general, Si-based materials have a relatively large volume change during charge and discharge compared to, for example, carbon materials. Therefore, when the electrode material layer contains an Si-based material, the sealing portion tends to be easily peeled off. Therefore, the technique disclosed herein can be applied to exert higher effects.

Drawings

Fig. 1 is a plan view schematically showing an all-solid battery according to an embodiment of the present invention.

Fig. 2 is a sectional view taken along line II-II of fig. 1.

Detailed Description

Hereinafter, embodiments of the all-solid-state battery disclosed herein will be described with reference to the drawings as appropriate. Note that, of course, the embodiments described herein are not intended to limit the technology disclosed herein. Matters necessary for implementation of the technology disclosed herein, other than the matters specifically mentioned in the present specification, can be grasped as design matters by those skilled in the art based on the conventional technology in the art. The all-solid battery disclosed herein can be implemented based on the disclosure of the present specification and the technical common knowledge in the art. In the present specification, when a numerical range is described as a to B (wherein A, B is an arbitrary number), the numerical range is a value from a to B.

In the following drawings, members and portions that exhibit the same functions are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified. In the drawings, the reference symbol Z denotes the stacking direction of the stacked electrode body. The reference symbol X in the drawings indicates the longitudinal direction of the laminated electrode body orthogonal to the lamination direction Z. The symbol Y in the drawing indicates a short-side direction of the laminated electrode body orthogonal to the lamination direction Z. Reference numeral L, R in the drawings denotes right and left in the short-side direction, respectively. However, these are merely directions for convenience of explanation, and the arrangement of the all-solid-state battery is not limited at all.

Fig. 1 is a plan view schematically showing an all-solid battery 1. Fig. 2 is a sectional view of the all-solid battery 1 taken along line II-II. The all-solid-state battery 1 is an electric storage device capable of storing electric power. The all-solid battery 1 is typically a secondary battery that can be charged and discharged. The secondary battery may be, for example, a lithium ion secondary battery, a nickel metal hydride battery, a lithium ion capacitor, an electric double layer capacitor, or the like. The all-solid battery 1 may be a sulfide solid battery, an oxide solid battery, or the like. As shown in fig. 1, the all-solid battery 1 of the present embodiment includes a laminated electrode assembly 10 and a sealing portion 20 that covers at least a laminated end face (edge face) 10e of the laminated electrode assembly 10. Here, the all-solid battery 1 is a laminate type battery using a laminate film as an exterior body. The all-solid battery 1 is configured by housing and sealing the laminated electrode assembly 10 and the sealing part 20 in a laminated rectangular battery case 1 c. Hereinafter, each constituent element will be described in turn.

As shown in fig. 2, the laminated electrode assembly 10 includes a positive electrode 12, a negative electrode 14, and a solid electrolyte layer 16. The laminated electrode assembly 10 includes a structural portion in which the positive electrode 12 and the negative electrode 14 are physically integrated by being laminated in the lamination direction Z with the solid electrolyte layer 16 interposed therebetween. The positive electrode 12 includes a positive electrode current collector 12a and positive electrode material mixture layers 12b fixed to both surfaces of the positive electrode current collector 12 a. The negative electrode 14 includes a negative electrode current collector 14a and negative electrode mixture layers 14b fixed to both surfaces of the negative electrode current collector 14 a. The solid electrolyte layer 16 is disposed between the positive electrode mixture layer 12b and the negative electrode mixture layer 14b in the stacking direction Z, and insulates the positive electrode 12 and the negative electrode 14 from each other. The positive electrode mixture layer 12b and the negative electrode mixture layer 14b are laminated in the lamination direction Z via the solid electrolyte layer 16. The positive electrode mixture layer 12b and the solid electrolyte layer 16 are interface-bonded. The negative electrode mixture layer 14b and the solid electrolyte layer 16 are interface-bonded.

the positive electrode 12 is sheet-shaped. As shown in fig. 1, the positive electrode 12 is rectangular in plan view. A tab portion 12t, from which the positive electrode current collector 12a is exposed, is provided at one end of the positive electrode 12 in the longitudinal direction X. The positive electrode 12 is electrically connected to the positive electrode terminal 13 via the electrode lug portion 12 t. The positive electrode terminal 13 is a connection terminal drawn from the inside to the outside of the battery case 1 c. In the present embodiment, the positive electrode 12 includes a positive electrode current collector 12a and positive electrode material mixture layers 12b fixed to both surfaces of the positive electrode current collector 12 a. However, the positive electrode 12 may not have the positive electrode collector 12 a. The positive electrode mixture layer 12b may be fixed to only one surface of the positive electrode current collector 12 a. The positive electrode collector 12a is a conductive member. The positive electrode current collector 12a is made of a metal having good conductivity, such as Al, Ti, and Ni, although not particularly limited.

₃The positive electrode mixture layer 12b typically contains a positive electrode active material and a binder resin, the positive electrode active material is a material capable of reversibly absorbing and releasing charge carriers (for example, lithium ions), but examples of the positive electrode active material include a metal oxide containing 1 or 2 or more metal elements and oxygen elements, the metal oxide may be a compound containing lithium element, 1 or 2 or more transition metal elements, and oxygen elements, preferred examples of the metal oxide include a lithium-nickel-containing composite oxide, a lithium-cobalt-containing composite oxide, a lithium-nickel-cobalt-containing composite oxide, a lithium-manganese-containing composite oxide, and a lithium-nickel-cobalt-manganese-containing composite oxide.

Examples of the binder resin include halogenated vinyl resins such as polyvinylidene fluoride (PVdF), and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), rubbers such as Butadiene Rubber (BR), Acrylic Butadiene Rubber (ABR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (isobutylene-isoprene rubber), ethylene-propylene rubber, ethylene-propylene-diene rubber, urethane rubber, silicone rubber, fluororubber, and natural rubber; polyolefin resins such as polyethylene and polypropylene; polyimide resins such as polyimide, polyamideimide, and polyetherimide. The binder resin may be a diene rubber having a double bond in the main chain, for example, a butadiene rubber containing 30 mol% or more of butadiene based on the whole. The SP value (SPp) of the binder resin contained in the positive electrode mixture layer 12b may be, for example, 15 or less, 10 or less, 9 or less, or 5 or more, 7 or more, or 8 or more. When the positive electrode mixture layer 12b contains a plurality of resin materials, the mass weighted average of the SP values of the respective resin materials may be SPp.

The mixing ratio of the binder resin in the positive electrode mixture layer 12b is not particularly limited, and may be, for example, 0.1 to 20 parts by mass, 1 to 10 parts by mass, or 3 to 7 parts by mass, when the total amount of the positive electrode active material is 100 parts by mass.

The positive electrode mixture layer 12b may contain other components, such as a solid electrolyte material, a conductive material, and various additives, as necessary, in addition to the positive electrode active material and the binder resin. The solid electrolyte material is an inorganic solid electrolyte material such as a sulfide solid electrolyte material, an oxide solid electrolyte material, a nitride solid electrolyte material, or a halide solid electrolyte material. More specifically, the material constituting the solid electrolyte layer 16 includes a sulfide solid electrolyte material as described later. Examples of the conductive material include carbon materials such as acetylene black, carbon black, graphite, carbon fiber, and carbon nanotube.

The negative electrode 14 is sheet-shaped. As shown in fig. 1, the negative electrode 14 is rectangular in plan view. An ear portion 14t where the negative electrode current collector 14a is exposed is provided at one end of the negative electrode 14 in the longitudinal direction X. The tab portion 14t is provided on the same side as the tab portion 12t on the positive electrode side. Negative electrode 14 is electrically connected to negative electrode terminal 15 via tab portion 14 t. The negative electrode terminal 15 is a connection terminal drawn from the inside to the outside of the battery case 1 c. The negative terminal 15 is drawn from the same side as the positive terminal 13. In the present embodiment, the negative electrode 14 includes a negative electrode current collector 14a and negative electrode mixture layers 14b fixed to both surfaces of the negative electrode current collector 14 a. However, the negative electrode 14 may not have the negative electrode current collector 14 a. The negative electrode mixture layer 14b may be fixed to only one surface of the negative electrode current collector 14 a. The negative electrode collector 14a is a conductive member. The negative electrode current collector 14a is made of a metal having good conductivity, such as Cu, Ti, and Ni, although not particularly limited.

The negative electrode mixture layer 14b typically contains a negative electrode active material and a binder resin. The negative electrode active material is a material capable of reversibly occluding and releasing charge carriers (e.g., lithium ions). Examples of the negative electrode active material include, but are not particularly limited to, hard carbon, graphite, carbon materials such as boron-added carbon, metal materials including Al, Si, Ti, In, Sn, etc., metal compounds including metal elements, metal oxides, Li metal compounds, and Li metal oxides. As the Li metal oxide, for example, a lithium transition metal composite oxide such as lithium titanate can be exemplified. The negative electrode active material may be, for example, a Si-based material in which the proportion of silicon (Si) is substantially 50 mass% or more. The proportion of Si in the entire negative electrode active material may be, for example, 80 mass% or more. The Si-based material may be at least 1 of Si, Si alloy, Si compound, and Si mixture. The Si-based material undergoes a large volume change during charge and discharge (particularly during rapid charge and discharge). Therefore, when the negative electrode mixture layer 14b contains the Si-based material, the sealing portion 20 tends to be easily peeled off. Therefore, the technology disclosed herein is preferably applied.

The binder resin can be suitably used, for example, from among materials that can be used for the positive electrode mixture layer 12 b. In one embodiment, the negative electrode mixture layer 14b may contain the same binder resin as the positive electrode mixture layer 12 b. The binder resin of the same kind may account for 50 mass% or more of the entire binder resin contained in the negative electrode mixture layer 14 b. For example, the positive electrode mixture layer 12b and the negative electrode mixture layer 14b may each contain a rubber (e.g., butadiene rubber) as a binder resin. For example, the positive electrode mixture layer 12b and the negative electrode mixture layer 14b may each contain a vinyl halide resin as a binder resin. The SP value (SPn) of the binder resin contained in the negative electrode mixture layer 14b may be, for example, 15 or less, 10 or less, 9 or less, or 5 or more, 7 or more, or 8 or more. When the negative electrode mixture layer 14b contains a plurality of resin materials, the mass weighted average of the SP values of the respective resin materials may be SPn. In one embodiment, the absolute value of the difference between the SP value of the binder resin of the negative electrode mixture layer 14b and the SP value of the binder resin of the positive electrode mixture layer 12b may be within 3, within 2, within 1, or within 0.5. For example, the SP value of the binder resin of the negative electrode mixture layer 14b may be the same as the SP value of the binder resin of the positive electrode mixture layer 12 b.

The mixing ratio of the binder resin in the negative electrode mixture layer 14b is not particularly limited, and may be, for example, 0.1 to 20 parts by mass, 1 to 10 parts by mass, or 3 to 7 parts by mass, when the total amount of the negative electrode active material is 100 parts by mass.

The negative electrode mixture layer 14b may contain other components, such as a solid electrolyte material, a conductive material, and various additives, as necessary, in addition to the negative electrode active material and the binder resin. The solid electrolyte material and the conductive material can be suitably used, for example, from among materials exemplified as materials that can constitute the positive electrode mixture layer 12 b.

The solid electrolyte layer 16 has ion conductivity, for example, in a lithium ion secondary battery, Li ion conductivity is provided, the solid electrolyte layer 16 is insulating, the solid electrolyte layer 16 is typically thinner in the lamination direction Z than the positive electrode material mixture layer 12b and the negative electrode material mixture layer 12b, in the present embodiment, the solid electrolyte layer 16 is solid at room temperature (25 ℃), the solid electrolyte layer 16 contains at least a solid electrolyte material, the ion conductivity (for example, Li ion conductivity) of the solid electrolyte material may be, for example, 1 × 10 ^-5 S/cm or more, and further, 1 × 10 ^-4 S/cm or more at room temperature (25 ℃), the solid electrolyte material may be a glass (amorphous), may be a crystallized glass, or may be a crystalline, and the solid electrolyte material may be, for example, 1 or 2 or more of a sulfide solid electrolyte material, an oxide solid electrolyte material, a nitride solid electrolyte material, a halide solid electrolyte material, and the like.

Although not particularly limited, as the sulfide solid electrolyte material, for example, a Li ₂ S-P ₂ S ₅ -based material such as Li ₂ S-P ₂ S ₅, Li ₂ S-P ₂ S ₅ -LiI, Li ₂ S-P ₂ S ₅ -Li ₂ O, LiI-Li ₂ O-Li ₂ S-P ₂ S ₅, a Li ₂ S-SiS ₂ -based material, a Li ₂ S-P ₂ S ₃ -based material, a Li ₂ S-GeS ₂ -based material, a Li ₂ S-B ₂ S ₃ -based material, a sulfide material such as Li ₃ PO ₄ -P ₂ S ₅ -based material, a halogen-added sulfide material in which a halogen element is added to the above-mentioned sulfide material, and a lithium element, a phosphorus element, a sulfur element, and 1 or 2 or more halogen elements (for example, a compound oxide of Cl, Br and Br, at least 1 kind of halogen-doped lanthanum oxide, a lithium-doped lithium-lanthanum-doped perovskite-type oxide (for example, a lithium-doped lithium-.

the solid electrolyte layer 16 may contain other components, such as a binder resin, various additives, and the like, as necessary, in addition to the solid electrolyte material. The binder resin can be suitably used, for example, from among materials that can be used for the positive electrode mixture layer 12 b. The SP value (SPe) of the binder resin contained in the solid electrolyte layer 16 may be, for example, 15 or less, 10 or less, 9 or less, or 5 or more, 7 or more, or 8 or more. When the solid electrolyte layer 16 contains a plurality of resin materials, the mass weighted average of the SP values of the respective resin materials may be SPe. In one embodiment, the solid electrolyte layer 16 may contain the same binder resin as the positive electrode mixture layer 12b and the negative electrode mixture layer 14 b. For example, the positive electrode mixture layer 12b, the negative electrode mixture layer 14b, and the solid electrolyte layer 16 may each contain a rubber (e.g., butadiene-based rubber) as a binder resin. The binder resin of the same kind may account for 50 mass% or more of the entire binder resin contained in the solid electrolyte layer 16.

In one embodiment, the absolute value of the difference between the SP value of the binder resin of the solid electrolyte layer 16 and the SP value of the binder resin of the positive electrode mixture layer 12b may be within 3, within 2, within 1, or within 0.5. For example, the SP value of the binder resin of the solid electrolyte layer 16 and the SP value of the binder resin of the positive electrode mixture layer 12b may be the same. In another embodiment, the absolute value of the difference between the SP value of the binder resin of the solid electrolyte layer 16 and the SP value of the binder resin of the negative electrode mixture layer 14b may be within 3, within 2, within 1, or within 0.5. For example, the SP value of the binder resin of the solid electrolyte layer 16 and the SP value of the binder resin of the negative electrode mixture layer 14b may be the same. For example, the sulfide solid electrolyte material has a relatively large volume change during charge and discharge as compared with the other solid electrolyte materials. Therefore, in the case where a sulfide-containing solid electrolyte material is included in the solid electrolyte layer 16, there is a tendency that peeling of the sealing portion 20 easily occurs. Therefore, the SP value of the binder resin of the solid electrolyte layer 16 and the SP value of the binder resin of the positive electrode mixture layer 12b and/or the negative electrode mixture layer 14b preferably satisfy the above range. This can improve the adhesion and integrity of the laminated electrode assembly 10 and the sealing portion 20.

The mixing ratio of the binder resin in the solid electrolyte layer 16 is not particularly limited, but may be, for example, 0.1 to 20 parts by mass, 1 to 10 parts by mass, or 3 to 7 parts by mass, when the entire solid electrolyte material is 100 parts by mass.

In the present embodiment, the overall shape of the laminated electrode assembly 10 is substantially rectangular parallelepiped. The laminated electrode assembly 10 has a laminated end face 10e in which the laminated structure of the rectangular positive electrode 12, the solid electrolyte layer 16, and the rectangular negative electrode 14 is exposed along the lamination direction Z. The laminated end face 10e is located on the outer peripheral edge of the laminated electrode assembly 10 in plan view. In other words, the laminated end faces 10e are respectively located at both ends in the longitudinal direction X and both ends in the short direction Y of the laminated electrode body 10. The laminated electrode body 10 has 4 laminated end faces 10 e. The laminated end surface 10e includes a peripheral edge portion of the XY surface of the positive electrode mixture layer 12b and a peripheral edge portion of the XY surface of the negative electrode mixture layer 14 b. In the cross-sectional view of fig. 2, the width of the positive electrode mixture layer 12b in the short direction Y is smaller than the width of the negative electrode mixture layer 14b in the short direction Y. Therefore, the laminated end face 10e of the laminated electrode assembly 10 has a shape in which irregularities are repeated along the lamination direction Z.

The sealing portion 20 is provided along the stacking end face 10e of the stacked electrode assembly 10 around the stacked electrode assembly 10. The sealing portion 20 is an insulator. When 500V is applied using an insulation resistance meter, the resistance value of the sealing portion 20 is 100M Ω or more. The sealing portion 20 is attached to the laminated end face 10e of the laminated electrode body 10. The laminated electrode assembly 10 and the sealing part 20 have integrity to the extent that they do not fall down at least when turned upside down and left-right. The sealing portion 20 seals the peripheral edge portions of the XY surfaces of the positive and negative electrode material mixture layers 12b, 14 b. The sealing portion 20 has a function of suppressing the collapse of the peripheral edge portions of the positive and negative electrode mixture layers 12b, 14b and the slipping of the active material from the positive and negative electrode mixture layers 12b, 14 b.

the sealing portion 20 covers all of the 4 laminated end faces 10e of the laminated electrode body 10. That is, the sealing portion 20 surrounds the outer peripheral edge of the laminated electrode assembly 10 in a square shape in plan view. In the cross-sectional view, the seal portion 20 covers the entire length of the lamination end face 10e in the lamination direction Z. The length of the sealing portion 20 in the stacking direction Z is equal to or longer than the length of the stacked electrode assembly 10 in the stacking direction Z. In the cross-sectional view, the laminated end face 10e of the laminated electrode assembly 10 (for example, the peripheral edge portions of the positive and negative electrode mixture layers 12b, 14 b) is not exposed. In one embodiment, the sealing part 20 may further cover the upper and lower surfaces of the laminated electrode assembly 10 in the lamination direction Z. In other words, the sealing portion 20 may completely cover all 6 faces of the substantially rectangular parallelepiped laminated electrode body 10.

In fig. 2, the sealing portion 20 has a shape in which irregularities are repeated along the Z-shape in the stacking direction of the stacked electrode assembly 10. That is, the uneven shape of the laminated end face 10e of the laminated electrode assembly 10 is filled with the seal part 20 and spread evenly. A sealing portion 20 is disposed between a pair of negative electrodes 14 adjacent in the stacking direction Z. In the laminated electrode assembly 10 with the sealing portion 20, the total amount of the width of the positive electrode mixture layer 12b and the width of the sealing portion 20 is the same as the total amount of the width of the negative electrode mixture layer 14b and the width of the sealing portion 20 in the short side direction Y. Thus, the laminated electrode assembly 10 with the sealing portion 20 has excellent durability against loads from external forces in the longitudinal direction X and the lateral direction Y, for example.

The sealing portion 20 contains at least a sealing resin and insulating particles, and the sealing resin must satisfy at least one of (1) an absolute value Δ SP ₁ of a difference between SPp and SPs is | SPp-SPs | of 1.9 or less when the SP value of the binder resin contained in the positive electrode material mixture layer 12b is SPp and the SP value of the sealing resin is SPs, (2) an absolute value Δ SP ₂ of a difference between SPn and SPs is | SPn-SPs | of 1.9 or less when the SP value of the binder resin contained in the negative electrode material mixture layer 14b is SPn and the SP value of the sealing resin is SPs |, and each of the above (1) and (2) may be satisfied from the viewpoint of further improving the durability of the sealing portion 20, and the SP value (SPs) of the sealing resin may be 15 or less, 13 or less, 11 or more, or 5 or more, 7 or more, or 8 or more, and when the sealing portion 20 contains a plurality of resin materials, the SP value of the SP of the respective resin materials may be an average value of the weighted values of the SP.

From the viewpoint of improving the affinity between the positive and negative electrode material mixture layers 12b, 14b and the sealing part 20, it is preferable that Δ SP ₁ and Δ SP ₂ of the sealing resin are small, and may be, for example, 1 or less, 0.5 or less, and 0.1 or less, and particularly Δ SP ₁ and/or Δ SP ₂ may be substantially 0(0.05 or less), and in one embodiment, the sealing resin may further have the property that (3) when the SP value of the binder resin contained in the solid electrolyte layer 16 is SPe and the SP value of the sealing resin is SPs, the absolute value Δ SP ₃ ═ SPe-SPs | of the difference between SPp and SPs is 1.9 or less.

The sealing resin can be suitably used, for example, as a material exemplified as a binder resin that can be used for the positive electrode mixture layer 12 b. In one embodiment, the sealing resin may contain the same type of resin material as the binder resin contained in at least 1 of the positive and negative electrode mixture layers 12b and 14b and the solid electrolyte layer 16. The same resin material may account for 50 mass% or more of the entire sealing resin. For example, the binder resin and the sealing resin of the positive electrode material mixture layer 12b and/or the negative electrode material mixture layer 14b may each contain a rubber (e.g., butadiene rubber). For example, the binder resin and the sealing resin of the positive electrode mix layer 12b and/or the negative electrode mix layer 14b may each contain a vinyl halide resin (for example, PVdF).

The insulating particles are typically a material that is incompatible with the sealing resin. Therefore, the size and shape of the insulating particles are typically maintained in the sealing portion 20. The insulating particles may be inorganic particles or organic particles. Examples of the inorganic particles include, but are not particularly limited to, metal materials, ceramic materials, glass frits, glass fibers, and the like. Examples of the organic particles include thermoplastic resin materials called engineering plastics such as glass fiber reinforced plastics (FRTP). The shape of the insulating particles may be, for example, a powder such as a granular shape, a fibrous shape, or a flake shape.

the average particle diameter of the insulating particles (particle diameter corresponding to 50% of the cumulative frequency from the side having a smaller particle diameter in the volume-based particle size distribution measured by the laser diffraction scattering method; the same applies hereinafter) is typically smaller than that of the positive electrode active material and/or the negative electrode active material. The average particle diameter of the insulating particles is typically smaller than the solid electrolyte material that can be contained in the positive electrode mixture layer 12b and/or the negative electrode mixture layer 14 b. This can improve the airtightness and sealing performance of the sealing portion 20. The average particle diameter of the insulating particles may be, for example, 0.01 μm or more, 0.1 μm or more, 0.5 μm or more, or 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. The mixing ratio of the insulating particles in the sealing part 20 may be, for example, 1 to 100 parts by mass, 5 to 70 parts by mass, or 10 to 50 parts by mass, based on 100 parts by mass of the entire sealing resin.

The all-solid battery 1 including the laminated electrode assembly 10 with the sealing part 20 disclosed in fig. 1 can be produced by a production method including, for example, the following steps: (step 1) a step of preparing a laminated electrode assembly 10; (step 2) preparing a molten composition containing a sealing resin and insulating particles in a molten state; (step 3) a step of sealing the laminated electrode body 10 in a mold having a space portion one turn larger than the laminated electrode body 10 and reducing the pressure; and (step 4) a step of injecting the molten composition into the mold under reduced pressure, and then cooling the mold to form the sealing part 20 on the laminated end face 10e of the laminated electrode body 10. In the above-described manufacturing method, the sealing resin is once melted in step 2, whereby the compatibility and the integrity with the binder resin contained in the laminated electrode assembly 10 can be further improved. As a result, the sealing portion 20 can be formed on the laminated end face 10e of the laminated electrode assembly 10 in more firm adhesion.

As described above, in the all-solid-state battery 1, the compatibility between the binder resin and the sealing resin is improved, and the adhesion and the integrity between the laminated electrode assembly 10 and the sealing part 20 are improved. In addition, in the all-solid battery 1, the sealing portion 20 contains insulating particles, so that the mechanical strength of the sealing portion 20 is improved. As a result, in the all-solid battery 1, the sealing part 20 is less likely to peel off from the laminated end face 10e of the laminated electrode assembly 10, and the effect of the sealing part 20 can be achieved for a long period of time. For example, even when external force such as vibration is applied to the all-solid battery 1 and/or the laminated electrode assembly 10 repeatedly undergoes volume change during charge and discharge, it is possible to suppress the change in battery characteristics to a small value. Further, the outer peripheral edge of the laminated electrode assembly 10 is prevented from sagging and the active material is prevented from slipping off the positive and negative electrode mixture layers 12b and 14b, and high battery performance can be maintained for a long time.

The all-solid-state battery 1 disclosed herein can be used for various applications. For example, the present invention can be suitably used as a power source for a motor (driving power source) mounted in a vehicle. The type of vehicle is not particularly limited, but typically includes an automobile, such as a plug-in hybrid vehicle (PHV), a Hybrid Vehicle (HV), an Electric Vehicle (EV), and the like.

The following description will explain some examples of the present invention, but the present invention is not intended to be limited to the specific examples shown.

EXAMPLE 1

[ manufacture of Positive electrode ]

First, a lithium transition metal composite oxide in a particle form (LiNi _1/3 Mn _1/3 Co _{1/ 3} O ₂, average particle diameter 6 μm) was prepared as a positive electrode active material, and LiNbO ₃ was coated on the surface of the positive electrode active material particles by a sol-gel method, specifically, LiOC ₂ H ₅ and Nb (OC ₂ H ₅) ₅ were first dissolved in an ethanol solvent in equimolar amounts to prepare a raw material composition, and then, the raw material composition was applied to the surface of the positive electrode active material particles under atmospheric pressure using a rotational flow coating apparatus (model "SFP-01" manufactured by POWREX corporation), and at this time, the thickness of the raw material composition was adjusted to 5nm by adjusting the treatment time, and then, the positive electrode active material particles to which the raw material composition was adhered were heat-treated under atmospheric pressure at 350 ℃ for 1 hour, thereby producing a positive electrode active material coated with LiNbO ₃.

Next, the LiNbO ₃ -coated positive electrode active material prepared above and a glass ceramic (15LiBr-10LiI-75(0.75Li ₂ S · 0.25P ₂ S ₅) as a solid electrolyte material were mixed at a mass ratio of 75: 25 of the positive electrode active material to the solid electrolyte material to prepare a mixed powder, and then, an SBR-based binder (a copolymer of styrene to butadiene of 60: 40, SP value: 8.6) and acetylene black as a conductive material were weighed so as to be 6 parts by mass with respect to 100 parts by mass of the positive electrode active material, respectively, and the mixed powder, the SBR-based binder, and the conductive material were mixed with n-butyl butyrate as a solvent and stirred with a stirrer to prepare a slurry-like positive electrode forming composition (solid content: 40%), and the positive electrode forming composition was applied to the surface of an aluminum foil (positive electrode current collector, 15 μm thick) by an applicator, and was dried at 120 ℃.

[ production of cathode ]

First, particulate Si (average particle diameter 6 μm) and graphite (C) as negative electrode active materials and a glass ceramic (the same as the positive electrode) as a solid electrolyte material were mixed in a mass ratio of Si: c: solid electrolyte material 53.4: 1.6: 45, and adjusting to obtain mixed powder. Next, an SBR-based binder (a copolymer of styrene: butadiene 60: 40, SP value: 8.6) and acetylene black as a conductive material were weighed out to 6 parts by mass with respect to 100 parts by mass of Si (negative electrode active material). Then, the mixed powder, SBR-based binder, and conductive material were mixed with n-butyl butyrate as a solvent, and the mixture was stirred with a stirrer, thereby preparing a slurry-like composition for forming a negative electrode (solid fraction: 70%). The negative electrode-forming composition was applied to the surface of a copper foil (negative electrode current collector, thickness 15 μm) by a doctor blade method using an applicator, and heated and dried at 120 ℃ for 20 minutes. In this way, a negative electrode in which the negative electrode mixture layer is fixed to the negative electrode current collector was produced.

[ formation of solid electrolyte layer ]

Next, a glass ceramic as a solid electrolyte material (same as the positive electrode and the negative electrode) and an SBR-based binder (styrene: butadiene: 60: 40 copolymer, SP value: 8.6) as a binder resin were weighed so that the mass ratio of the SBR-based binder to the solid electrolyte material was 95: 5, and the solid electrolyte material and the SBR-based binder were mixed with heptane as a solvent, and mixed and stirred for 2 minutes by an ultrasonic dispersion device (model "UH-50" manufactured by SMT), thereby preparing a slurry-like composition for solid content of 70%, and the solid electrolyte composition was applied to the surface of a substrate (aluminum foil) so that the applied amount was 60mg/cm ² by a doctor blade method using an applicator, naturally dried, and then heated and dried at 100 ℃ for 30 minutes, thereby forming a sulfide solid electrolyte layer on the substrate.

[ production of laminated electrode Assembly ]

The solid electrolyte layer thus formed was first pressed into a square of 100cm ² area by a press, and pressed at 25 ℃ under a face pressure of 1 ton/cm ², and then a positive electrode was stacked on one face of the pressed solid electrolyte layer, and pressed at 25 ℃ under a face pressure of 1 ton/cm ², and at this time, the positive electrode was disposed so that the positive electrode mixture layer side was opposed to the solid electrolyte layer, and then the substrate attached to the surface of the solid electrolyte layer was peeled off, and a negative electrode was stacked on the exposed face of the solid electrolyte layer, and pressed at 25 ℃ under a face pressure of 6 ton/cm ², and at this time, the negative electrode was disposed so that the negative electrode mixture layer side was opposed to the solid electrolyte layer.

[ formation of seal portion ]

Next, the laminated electrode body thus produced was enclosed in a mold having a hollow portion, and the mold was pressurized. Then, the hollow portion in which the laminated electrode assembly is housed is decompressed. Next, a seal portion is integrally formed around the laminated electrode body by an injection molding method. Specifically, first, an SBR-based resin (a copolymer of styrene: butadiene 60: 40, SP value: 8.6) as a sealing resin and a glass fiber (average particle diameter 1.0 μm) as an insulating particle were mixed in the mass ratio of the SBR-based resin: glass fiber 100: 30, and mixing. And, the mixture was heated to 180 ℃ in a plunger to prepare a molten composition. Subsequently, the molten composition is injected from the runner portion of the mold and then cooled. Subsequently, the pressing of the mold is released, and the laminated electrode assembly is taken out from the mold. And, the excess resin of the runner portion is cut off. This produced a laminated electrode assembly with a sealing portion.

[ construction of all-solid-State Battery ]

First, an aluminum laminate film was prepared as an exterior material. As the aluminum laminated film, a film having a multilayer structure in which a nylon layer as an outermost layer, an aluminum layer as a barrier layer, and a polypropylene layer as a sealant layer are laminated in this order is used. Then, an all-solid battery (sulfide solid battery, example 1) was constructed by forming an aluminum laminated film into a bag shape, housing the laminated electrode assembly with a sealing portion obtained above, and sealing the same.

Examples 2 to 5

An all-solid battery was constructed in the same manner as in example 1, except that in example 2, the insulating particles in the sealing portion were changed to alumina powder (average particle size 2 μm, crushed product). An all-solid battery was constructed in the same manner as in example 1, except that in example 3, the type of sealing resin in the sealing portion and the type of binder resin in the positive and negative electrode mixture layers were all changed to PVdF (SP value: 7). An all-solid battery was constructed in the same manner as in example 1 except that in example 4, the type of sealing resin in the sealing portion was changed to BR (butadiene rubber, SP value: 8.2). An all-solid battery was constructed in the same manner as in example 1, except that in example 5, the type of the sealing resin in the sealing portion was changed to methyl acrylate (SP value: 10.1), and the type of the binder resin in the positive and negative electrode mixture layers was changed to SBR-based resin (copolymer of styrene and butadiene in a ratio of 80: 20, SP value: 8.2). The installation methods of examples 1 to 5 are summarized in Table 1.

Comparative examples 1 to 4

In comparative example 1, the laminated electrode assembly was housed in an aluminum laminated film with the peripheral edge portions of the positive and negative electrode material mixture layers open without forming a sealing portion, thereby constructing an all-solid battery. An all-solid battery was constructed in the same manner as in example 1, except that the type of sealing resin in the sealing portion was changed to polyamide (SP value: 13.6) in comparative example 2. An all-solid battery was constructed in the same manner as in example 1, except that in comparative example 3, the type of the sealing resin in the sealing portion was changed to PMMA (polymethyl methacrylate, SP value: 9.6), and the type of the binder resin in the positive and negative electrode mixture layers was changed to PVdF (SP value: 7). In comparative example 4, an all-solid battery was constructed in the same manner as in example 1, except that the sealing portion was not mixed with insulating particles, and the type of the sealing resin in the sealing portion was changed to an epoxy resin (SP value: 11.1), and the molten composition was injected into the mold during formation of the sealing portion, and then the temperature was maintained at 180 ℃. The installation methods of comparative examples 1 to 4 are summarized in Table 2.

TABLE 1

TABLE 2

Evaluation of the durability of the seal portion to cycles

The durability of the sealing part was evaluated for the all-solid batteries (examples 1 to 5 and comparative examples 1 to 4) constructed as described above. Specifically, each battery was subjected to a 100-cycle charge/discharge test (voltage range: 3.0 to 4.2V, charge/discharge rate: 1C, charge method: Constant Current (CC) -Constant Voltage (CV) charge/discharge) in an environment of 25 ℃. After the charge and discharge test, the exterior material was disassembled (laminated), and it was confirmed that (a) the presence or absence of cracks in the sealed portion and (b) the presence or absence of solid matter (particles) slipping off from the laminated electrode body. The results are shown in the corresponding columns of tables 1 and 2. In tables 1 and 2, ". smallcircle" indicates that both (a) and (b) are not confirmed, and "x" indicates that (a) and/or (b) are confirmed.

Evaluation of insulation Retention of all-solid-State Battery

The durability of the laminated electrode body was evaluated for the all-solid batteries (examples 1 to 5 and comparative examples 1 to 4) constructed as described above. Specifically, first, a charge/discharge test was performed for 100 cycles in the same manner as described above. After the charge and discharge test, the insulation between the laminated electrode body and the exterior material was confirmed. Specifically, the resistance value between the tab portion of the current collector and the aluminum layer portion of the exterior material was measured using an insulation resistance meter. The results are shown in the corresponding columns of tables 1 and 2. In tables 1 and 2, ". smallcircle" indicates that the resistance value is 100 M.OMEGA.or more when 500V is applied, that is, the insulation property can be maintained, and "x" indicates that the resistance value is less than 100 M.OMEGA.that the insulation property cannot be maintained, and a short circuit occurs.

evaluation of vibration durability of seal portion

Vibration tests were performed on the all-solid-state batteries (examples 1 to 5 and comparative examples 1 to 4) constructed as described above, based on iso (international Organization for standardization)12405-1 (test of lithium ion battery pack for electric vehicle). This test is a complex random test in which a cell is given a complex random wave up to 200 Hz. This test simulates a state in which the vehicle is mounted, in which vibration of a low frequency of mainly 100Hz or less occurs due to, for example, running and vibration of a drive system. The test was started in a state where the all-solid battery was fully charged, and the presence or absence of an abnormality (for example, an internal short circuit) during and after the test was confirmed. The results are shown in the corresponding columns of tables 1 and 2. In tables 1 and 2, a to C represent the following.

"A": there was no abnormality in the test and the voltage drop after the test was less than 0.1V.

"B": there was no abnormality in the test, and the voltage drop after the test was 0.1V or more and less than 0.5V.

"C": a short circuit (voltage drop to 0V) occurred during the test, or the voltage drop after the test was 0.5V or more.

As shown in table 2, in comparative example 1 having no sealing portion, the insulation performance of the all-solid battery after the cycle test was degraded and the internal short circuit after the vibration test was confirmed. This is considered to be because the peripheral edge portions of the positive and negative electrode mixture layers are left open, and therefore, a short circuit occurs inside the battery due to charge-discharge cycles or vibration. In addition, comparative example 4 in which the insulating particles were not contained in the sealing portion gave the same result as comparative example 1 in which the sealing portion was not contained. This is considered to be because the strength of the seal portion is insufficient, and the effect of forming the seal portion is not sufficiently exerted. Comparative examples 2 and 3, in which the difference between the SP values of the sealing resin in the sealing portion and the binder resin in the electrode was large, were durable against charge and discharge cycles, but slightly less durable against vibration load. The reason for this is considered to be that the sealing portion gradually falls off from the positive and negative electrode material mixture layers because the affinity between the sealing resin of the sealing portion and the binder resin of the electrode is insufficient.

As shown in table 1, in examples 1 to 5 in which the difference in SP value between the sealing resin of the sealing portion and the binder resin of the electrode was suppressed to be relatively small within 1.9, the durability of the sealing portion against the vibration load and the charge-discharge cycle were all high as compared with those of the comparative examples. In other words, the variation in the battery characteristics is suppressed small with respect to the volume variation and the vibration load of the laminated electrode body. Such results show the technical significance disclosed herein. Further, as is clear from comparison of examples 1 and 2, the type of the insulating particles in the sealing portion is not particularly limited. As is clear from comparison of examples 1, 3, 4, and 5, the types of the sealing resin of the sealing portion and the binder resin of the electrode are not limited.

The present invention has been described in detail above, but the above embodiments and examples are merely illustrative, and the invention disclosed herein includes various modifications and alterations to the specific examples described above.

For example, in the above embodiment, the solid electrolyte layer 16 is configured to contain a solid electrolyte material. But is not limited thereto. The solid electrolyte layer 16 may be, for example, a polymeric gel electrolyte comprising a supporting salt (e.g., a lithium salt) in a polymer matrix. Examples of the polymer gel electrolyte include, but are not particularly limited to, an electrolyte in which a polymer electrolyte such as polyethylene oxide (PEO) is impregnated with an electrolyte solution of a general lithium ion secondary battery; an electrolyte in which an electrolyte solution of a general lithium ion secondary battery is held in a skeleton of a polymer compound having no lithium ion conductivity such as polyvinylidene fluoride (PVdF).

For example, in the above embodiment, the laminated electrode assembly 10 includes the positive electrode 12, the negative electrode 14, and the solid electrolyte layer 16, and the positive electrode 12 and the negative electrode 14 are laminated with the solid electrolyte layer 16 interposed therebetween. That is, the laminated electrode assembly 10 does not have a bipolar electrode as disclosed in japanese patent application laid-open No. 2005-5163. But is not limited thereto. The laminated electrode body may include, for example, a plurality of bipolar electrodes in which a positive electrode mixture layer is fixed to one surface of a collector and a negative electrode mixture layer is fixed to the other surface, instead of the positive electrode 12 and the negative electrode 14. The laminated electrode body may be configured by laminating a plurality of bipolar electrodes with a solid electrolyte layer interposed therebetween. The all-solid-state battery including such a laminated electrode assembly can also be suitably used in the same manner as the all-solid-state battery 1.

For example, in the above embodiment, the battery case 1c is laminated. But is not limited thereto. The battery case 1c may be made of, for example, resin or metal. The battery case 1c may include a case body in a flat rectangular parallelepiped shape having an open upper surface, and a lid body that closes the open upper surface of the case body.

For example, in the above embodiment, the tab portion 12t on the positive electrode side and the tab portion 14t on the negative electrode side are provided on the same side in the longitudinal direction X, and the positive electrode terminal 13 and the negative electrode terminal 15 are drawn from the same side in the longitudinal direction X of the laminated electrode assembly 10. But is not limited thereto. The positive electrode-side tab 12t and the negative electrode-side tab 14t may be provided on opposite sides in the longitudinal direction X, for example, with the laminated electrode assembly 10 interposed therebetween. In this case, the positive electrode terminal 13 and the negative electrode terminal 15 may be drawn out from opposite sides in the longitudinal direction X, for example, with the laminated electrode assembly 10 interposed therebetween.