JP6915587B2 - Laminated battery manufacturing method - Google Patents

Description

The present disclosure relates to a method for manufacturing a laminated battery.

A laminated battery having a plurality of laminated bodies having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order in the thickness direction is known. For example, Patent Document 1 describes a method for manufacturing a laminated battery, which comprises a step of supplying a liquid resin only to the side surface of the laminated battery and a step of curing the liquid resin. The manufacturing method of is disclosed. In Patent Document 1, at least one of the positive electrode current collector layer, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector layer is extended more than the other layers to form an extended layer. It is disclosed that a laminated battery capable of improving the energy density can be obtained.

Patent Document 2 describes the manufacture of an all-solid-state battery in which a resin coating layer is formed by insert molding on a laminate having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order. The method is disclosed. Patent Document 2 describes a method for manufacturing an all-solid-state battery, a step of arranging resin films on both front and back surfaces in the thickness direction of the laminate in advance, and a step of sealing the side surfaces of the laminate with an insert resin. It is disclosed that an all-solid-state battery capable of suppressing insufficient wraparound of the resin in insert molding and thinning the resin layers on both sides in the thickness direction of the battery can be obtained.

In the method for manufacturing a laminated battery, a laminated battery having a plurality of laminated bodies in the thickness direction may have a deviation in the laminated position of each layer. As a method of eliminating the deviation, for example, a method of pressing the deviation against a block or the like to adjust the stacking position can be mentioned. On the other hand, for example, since the electrode layer constituting the laminated battery has a thin plate shape, there may be a problem that the end portion of the electrode layer is chipped when pressed against a block or the like. Therefore, for example, as in Patent Document 1, a method has been proposed in which a plurality of laminated bodies are laminated in the thickness direction and then only the side surface of the laminated battery is fixed with a resin. By adopting a method of fixing only the side surface of the laminated battery with a resin, it is possible to improve the handleability of the laminated battery, suppress chipping of the end portion of the electrode layer, and improve the quality.

JP-A-2017-220447 Japanese Unexamined Patent Publication No. 2015-050004

By the way, when the side surface of the laminated body is filled with the resin, if the resin is excessively filled inside the laminated body, the battery performance may be deteriorated. Further, if the side surface of the laminated body cannot be sufficiently filled with the resin, it becomes difficult to fix the side surface of the laminated battery, and the respective layers constituting the laminated battery may be displaced.

The present disclosure has been made in view of the above circumstances, and when the side surface of the laminated body is filled with the resin, the side surface of the laminated body can be sufficiently filled with the resin, and the inside of the laminated body is filled with the resin. An object of the present invention is to provide a method for manufacturing a laminated battery capable of suppressing excessive filling.

In order to achieve the above problems, a method for manufacturing a laminated battery having a plurality of laminates having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order in the thickness direction. The first step of applying a restraining pressure to the plurality of laminates using a jig in the thickness direction, the second step of filling the side surfaces of the plurality of laminates with a photocurable resin, and the photocurability. It has a third step of irradiating the resin with light to cure the photocurable resin, and in the second step, the viscosity of the photocurable resin at the time of filling is 1000 mPa · s or more and 25,000 mPa · s or less. Provided is a method for manufacturing a laminated battery.

According to the present disclosure, in the second step, the viscosity of the photocurable resin at the time of filling is 1000 mPa · s or more and 25000 mPa · s or less. It is possible to suppress excessive filling of the resin into the resin. Further, since the third step is a step of irradiating the photocurable resin with light to cure the photocurable resin, the productivity and cost are improved as compared with the case where the conventional thermosetting resin is used. A laminated battery can be obtained by an excellent method.

In the method for manufacturing a laminated battery in the present disclosure, when the side surface of the laminated body is filled with the resin, the side surface of the laminated body can be sufficiently filled with the resin, and the excessive filling of the resin inside the laminated body is suppressed. It has the effect of being able to obtain a laminated battery that can be used.

It is a schematic process diagram which shows an example of the manufacturing method of the laminated battery in this disclosure. It is a schematic process diagram which shows another example of the manufacturing method of the laminated battery in this disclosure. It is a schematic process diagram which shows another example of the manufacturing method of the laminated battery in this disclosure. It is a schematic process diagram which shows another example of the manufacturing method of the laminated battery in this disclosure. It is explanatory drawing for demonstrating the current collector layer in this disclosure. It is explanatory drawing for demonstrating the manufacturing method of the conventional laminated battery. It is explanatory drawing for demonstrating the manufacturing method of the conventional laminated battery. It is explanatory drawing for demonstrating the laminated battery obtained by the manufacturing method of the laminated battery in this disclosure.

Hereinafter, the method for manufacturing a laminated battery in the present disclosure will be described in detail.

The method for manufacturing a laminated battery in the present disclosure is a manufacturing method in which a plurality of laminated bodies having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order are provided in the thickness direction. A first step of applying a restraining pressure to a plurality of laminated bodies using a jig in the thickness direction, a second step of filling the side surfaces of the plurality of laminated bodies with a photocurable resin, and the above-mentioned photocurable resin. Has a third step of irradiating light to cure the photocurable resin, and in the second step, the viscosity of the photocurable resin at the time of filling is 1000 mPa · s or more and 25,000 mPa · s or less. There is a manufacturing method.

The manufacturing method of the laminated battery in the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic process diagram showing an example of the method for manufacturing a laminated battery in the present disclosure. In the method for manufacturing a laminated battery in the present disclosure, a laminated body 10 having a plurality of laminated bodies 10 having a positive electrode current collector layer 41, a positive electrode layer 1, a solid electrolyte layer 3, a negative electrode layer 2 and a negative electrode current collector layer 42 in this order is provided in this order. This is a method for manufacturing the battery 100. The method for manufacturing a laminated battery in the present disclosure includes a first step (FIG. 1 (a)) of applying a restraining pressure to a plurality of laminated bodies 10 using a jig 20 in the thickness direction, and side surfaces of the plurality of laminated bodies 10. The second step (FIG. 1 (b)) of filling the photocurable resin 30'and the third step (FIG. 1) of irradiating the photocurable resin 30' with light to cure the photocurable resin 30'. (C)) and. Further, in the present disclosure, in the second step, the viscosity of the photocurable resin 30'when filled is 1000 mPa · s or more and 25000 mPa · s or less. The thickness direction is the thickness direction of each layer, and corresponds to the direction in which each layer constituting the laminated body is laminated. Specifically, it refers to the direction of the arrow indicated by the reference numeral x in FIG. 1 (a). The side surface of the laminated body means a surface of the laminated body in a direction orthogonal to the thickness direction x, and is a surface pointed by an arrow indicated by a symbol y in FIG. 1 (a). Further, reference numeral 30 refers to a cured product obtained by curing the photocurable resin 30'by light irradiation.

2 (a) to 2 (c) are schematic process diagrams showing another example of the method for manufacturing a laminated battery in the present disclosure. The method for manufacturing a laminated battery in the present disclosure includes a first step (not shown) of applying a restraining pressure to a plurality of laminated bodies using a jig in the thickness direction, and a photocurable resin 30'in a container. The second step (FIG. 2A) of pouring and filling the side surfaces of a plurality of laminated bodies, and the laminating body in which the side surface of the laminated body on which the photocurable resin is poured is irradiated with light and the photocurable resin is further poured. The side surface of the body may have a third step (FIGS. 2 (b) and (c)) of irradiating light from another side surface side. Reference numerals not described in FIGS. 2 (a) to 2 (c) can be the same as those in FIGS. 1 (a) to 1 (c), and thus the description thereof will be omitted here.

3 (a) to 3 (c) are schematic process diagrams showing another example of the method for manufacturing a laminated battery in the present disclosure. The method for manufacturing a laminated battery in the present disclosure includes a first step (not shown) of applying a restraining pressure to a plurality of laminated bodies using a jig in the thickness direction, and a plurality of photocurable resins 30'using a dispenser. The second step (FIG. 3 (a)) of discharging and filling the side surface (long side side) of the laminate, and irradiating the side surface (long side) of the laminate on the side where the photocurable resin is discharged with light. The third step (FIG. 3 (b)) and the second second step (FIG. 3 (c)) of discharging the photocurable resin 30'to the side surface (short side side) of the plurality of laminates using a dispenser. And a second third step (not shown) of irradiating the side surface (short side side) of the laminate on the side where the photocurable resin is discharged with light. In the present disclosure, as shown in FIGS. 3A to 3C, the second step and the third step may be repeated. By repeating the second step and the third step, the photocurable resin can be cured after the photocurable resin is discharged to one side surface, and then the photocurable resin is discharged to the other side surface. At that time, it is possible to suppress the occurrence of problems such as the photocurable resin discharged to one side surface flowing out. Reference numerals not described in FIGS. 3 (a) to 3 (c) can be the same as those in FIGS. 1 (a) to 1 (c), and thus the description thereof will be omitted here.

4 (a) and 4 (b) are schematic process diagrams showing another example of the method for manufacturing a laminated battery in the present disclosure. The method for manufacturing a laminated battery in the present disclosure includes a first step (not shown) of applying a restraining pressure to a plurality of laminated bodies in the thickness direction of the laminated body using a jig, entering a container, and heating with a heater. The second step (FIG. 4A) in which the photocurable resin 30'is poured into the side surface of the laminate and filled with a scraper, and the side surface of the laminate on which the photocurable resin is poured is irradiated with light. It may have a third step (FIG. 4 (b)). Reference numerals not described in FIGS. 4 (a) and 4 (b) can be the same as those in FIGS. 1 (a) to 1 (c), and thus the description thereof will be omitted here.

According to the present disclosure, when the side surface of the laminated body is filled with the resin, the side surface of the laminated body can be sufficiently filled with the resin, and the excessive filling of the resin into the inside of the laminated body can be suppressed. It is possible to provide a method for manufacturing a laminated battery. The following can be inferred as specific reasons.

First, when the side surface of the laminated body is filled with the resin, if the viscosity of the resin is high, for example, as shown in FIGS. A void as indicated by R may occur. This is considered to be one of the factors that the laminating gap of each layer in the laminated body is several tens of μm, and if the viscosity of the resin is high, it becomes difficult for the resin to sufficiently spread in the laminating gap. On the other hand, when the side surface of the laminated body is filled with the resin, if the viscosity of the resin is low, the resin 40 may be excessively filled inside the laminated body, for example, as shown in FIG. In this case, there is a problem that the performance of the obtained laminated battery is deteriorated. On the other hand, the method for manufacturing a laminated battery in the present disclosure includes a second step of filling the side surfaces of a plurality of laminated bodies with a photocurable resin, and in the second step, the viscosity of the photocurable resin at the time of filling is increased. The above problem can be solved by having 1000 mPa · s or more and 25000 mPa · s or less. Specifically, it is as follows. Note that FIG. 6A is a schematic diagram for explaining a conventional laminated battery, and FIG. 6B is an image thereof. Further, FIG. 7 is a schematic diagram for explaining a conventional laminated battery. Reference numerals not described in FIGS. 6 (a), 6 (b) and 7 can be the same as those in FIGS. 1 (a) to 1 (c), and thus the description thereof will be omitted here.

That is, since the viscosity before contacting the photocurable resin laminate is in the above range, which is relatively low, when the photocurable resin is poured into the side surface of the laminate, the lamination gap on the side surface of the laminate is sufficient. Can be filled with a photocurable resin. Further, since the photocurable resin can usually have the above viscosity by heating, the photocurable resin that has been heated immediately after the heated photocurable resin is poured into the side surface of the laminate. The temperature gradually decreases. The temperature of the laminate is usually room temperature (25 ° C.). Therefore, the reason why the temperature of the photocurable resin gradually decreases is that when the heated photocurable resin comes into contact with the laminate, the heated photocurable resin heats up to the laminate at room temperature. It is possible to move. In the present disclosure, by pouring a heated photocurable resin into the side surface of the laminate, the temperature of the heated photocurable resin gradually decreases, so that the photocurability as the temperature decreases. The viscosity of the resin increases. Therefore, the viscosity of the photocurable resin poured into the side surface of the laminate is increased, so that excessive filling into the inside of the laminate is suppressed. From the above, when the side surface of the laminated body is filled with the resin, the side surface of the laminated body can be sufficiently filled with the resin, and the excessive filling of the resin into the inside of the laminated body can be suppressed. Guessed. That is, for example, as shown in FIGS. 8A and 8B, the side surface of the laminated battery 100 can be sufficiently filled with the photocurable resin 30 and fixed. 8 (a) is a schematic perspective view showing an example of a laminated battery obtained by the method for manufacturing a laminated battery in the present disclosure, and FIG. 8 (b) is a cross-sectional view taken along the line AA of FIG. 8 (a). be. Reference numerals not described in FIGS. 8A and 8B can be the same as those in FIGS. 1A to 1C, and thus the description thereof will be omitted here.

By the way, in Patent Document 1, a thermosetting resin is used as a resin to be filled on the side surface of the laminated body. On the other hand, when a thermosetting resin is used, it is necessary to apply heat to cure it (for example, it is necessary to heat it in an oven at a temperature of 80 ° C. for 150 minutes), which poses problems in terms of productivity and cost. Further, the thermoplastic resin has a softening point in the operating temperature range (80 ° C. to 100 ° C.) or higher in a vehicle. Therefore, in order to adjust the viscosity of the thermoplastic resin, it is necessary to heat it to such a temperature range. On the other hand, from the viewpoint of suppressing deterioration of the performance of the laminated battery, heating at, for example, 140 ° C. or lower is required. However, no thermoplastic resin satisfies such a requirement. Further, the reactive curable resin (for example, an epoxy-based two-component curable resin, one-component curable resin, etc.) has a large shrinkage of the resin at the time of curing, and when the side surface of the laminate is filled and cured, the laminate Stress may be applied to the side surface of the laminate and the edges of the laminate may be damaged. On the other hand, in the present disclosure, the above-mentioned problems can be solved by using a photocurable resin.

Here, "having a plurality of laminates having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order in the thickness direction" means that the positive electrode current collector layer, the positive electrode layer, and the like. A laminated body in which a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer are laminated in this order is repeatedly laminated, and a state in which a plurality of unit cells are laminated. That is, the "laminated battery" is composed of a plurality of unit cells.

Hereinafter, each step of the method for manufacturing a laminated battery in the present disclosure will be described.

1. 1. First Step The first step is a step of applying a restraining pressure to a plurality of laminated bodies using a jig in the thickness direction.

The restraining pressure applied to the plurality of laminated bodies in the thickness direction is not particularly limited. The specific restraining pressure is, for example, 0.1 MPa or more, 1 MPa or more, or 5 MPa or more. By increasing the restraining pressure, there is an advantage that the contact between the layers can be easily improved. On the other hand, the restraining pressure may be, for example, 100 MPa or less, 50 MPa or less, or 20 MPa or less. If the restraining pressure is made too large, the jig that applies the restraining pressure is required to have high rigidity, and the jig may become large.

Hereinafter, each configuration of the laminated battery will be described.

(1) Laminated body The laminated body in the present disclosure is a cell having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order. The laminate is typically a Li ion cell that utilizes Li ion conduction. Further, the laminated body is preferably a cell (secondary battery) capable of charging and discharging.
Hereinafter, each configuration of the laminated body will be described.

(A) Positive electrode current collector layer, negative electrode current collector layer The positive electrode current collector layer and negative electrode current collector layer may have a function of collecting current from the positive electrode layer and the negative electrode layer in an all-solid-state battery. As shown in FIGS. 1A to 1C, for example, the positive electrode current collector layer and the negative electrode current collector layer have a function of collecting current from the electrode layer (positive electrode layer or negative electrode layer) in one laminated body. , It may also have a function of collecting electricity of the electrode layer (positive electrode layer or negative electrode layer) in another laminate adjacent to one laminate. Further, as shown in FIG. 5A, it may be an integrated layer (here, the current collector layer 4) that also has the functions of the positive electrode current collector layer and the negative electrode current collector layer. As shown in FIG. 5A, when the current collector layer 4 which also functions as the positive electrode current collector layer and the negative electrode current collector layer is provided, the positive electrode layer 1, the current collector layer 4, and the negative electrode are provided. It is preferable that the layer 2 and the layer 2 form the bipolar electrode layer 5. By configuring the bipolar electrode layer 5, the total number of laminated batteries can be reduced as compared with the case where the positive electrode current collector layer and the negative electrode current collector layer are provided, and a laminated battery having a higher energy density can be obtained. Can be done. The laminated battery 100 when the bipolar electrode layer 5 is configured is illustrated in FIG. 5B, for example. Reference numerals not described in FIGS. 5A and 5B can be the same as those in FIGS. 1A to 1C, and thus the description thereof will be omitted here.

The metal elements contained in the positive electrode current collector layer and the negative electrode current collector layer are not particularly limited, and examples thereof include Al, Fe, Ti, Ni, Zn, Cr, Au, and Pt. The current collector layer may be a simple substance of the metal element, or may be an alloy containing the metal element as a main component. Examples of Fe alloys include stainless steel (SUS).

Examples of the shape of the positive electrode current collector layer and the negative electrode current collector layer include a foil shape and a mesh shape. The thickness of the positive electrode current collector layer and the negative electrode current collector layer is, for example, 0.1 μm or more, and may be 1 μm or more. On the other hand, the thickness of the positive electrode current collector layer and the negative electrode current collector layer is, for example, 1 mm or less, and may be 100 μm or less.

(B) Positive electrode layer The positive electrode layer is a layer containing at least a positive electrode active material. The positive electrode layer may contain at least one of a solid electrolyte, a binder and a conductive material, if necessary.

The positive electrode active material is appropriately selected according to the type of the all-solid-state battery, and examples thereof include an oxide active material and a sulfide active material. Examples of the positive electrode active material include a rock salt layered active material such as _{lithium cobalt oxide (LiCoO 2} ), lithium nickel oxide (LiNiO ₂ ), LiNi _1/3 Co _1/3 Mn _1/3 O _{2, and lithium manganate (Lithium manganate (LiNiO 2).} LiMn ₂ O ₄ ), Li (Ni _0.5 Mn _1.5 ) O ₄ , Li _{1 + x} Mn _{2- xy My} O ₄ (M is selected from Al, Mg, Co, Fe, Ni, Zn) Examples thereof include spinel-type active materials such as (1 or more), and olivine-type active materials such as _{lithium titanate (Li x} TiO _y ), LiFePO ₄ , LiMnPO _{4 , LiCoPO 4} , and LiNiPO _4.

A coating layer may be formed on the surface of the positive electrode active material contained in the positive electrode layer. Examples of the material of the coating layer include LiNbO ₃ , Li ₃ PO ₄ , Li ₄ Ti ₅ O _{12 and the} like. The thickness of the coating layer is, for example, 0.1 nm or more, and may be 1 nm or more. On the other hand, the thickness of the coating layer is, for example, 100 nm or less, and may be 20 nm or less. The coverage of the coating layer on the surface of the positive electrode active material is, for example, 50% or more, and may be 80% or more.

The solid electrolyte is not particularly limited, and examples thereof include inorganic solid electrolytes such as sulfide solid electrolytes and oxide solid electrolytes. Examples of the sulfide solid electrolyte include Li ₂ S-P ₂ S ₅ , Li ₂ S-P ₂ S ₅ -Li I, Li ₂ S-P ₂ S ₅ -Li I-Li Br, Li ₂ S-P ₂ S ₅ -Li ₂ O, Li ₂ S-P ₂ S ₅ -Li ₂ O-LiI, Li ₂ S-SiS ₂ , Li ₂ S-SiS _2- LiI, Li ₂ S-SiS _2- LiBr, Li ₂ S-SiS _2- LiCl, Li ₂ S-SiS _2- B ₂ S ₃ -Li I, Li ₂ S-SiS _2- P ₂ S ₅ -Li I, Li ₂ S-B ₂ S ₃ , Li ₂ S-P ₂ S _5- Z _m S _n (where m and n are positive numbers. Z is any of Ge, Zn, Ga), Li ₂ S-GeS ₂ , Li ₂ S-SiS _{2 -Li 3} PO ₄ , Li ₂ Examples thereof include S-SiS _{2- Li x} MO _y (where x and y are positive numbers, and M is any of P, Si, Ge, B, Al, Ga and In). The above description of "Li ₂ SP ₂ S ₅ " means a sulfide solid electrolyte made by using a raw material composition containing _{Li 2} S and P ₂ S _{5, and the same applies to other descriptions.} ..

Examples of the conductive material include carbon materials such as acetylene black (AB), Ketjen black (KB), carbon fiber, carbon nanotube (CNT), and carbon nanofiber (CNF). Examples of the binder include rubber-based binders such as butylene rubber (BR) and styrene-butadiene rubber (SBR), and fluoride-based binders such as polyvinylidene fluoride (PVDF).

The thickness of the positive electrode layer can be, for example, 0.1 μm or more and 1000 μm or less.

(C) Negative electrode layer The negative electrode layer is a layer containing at least a negative electrode active material. The negative electrode layer may contain at least one of a solid electrolyte, a binder and a conductive material, if necessary.

The negative electrode active material is not particularly limited, and examples thereof include a metal active material, a carbon active material, and an oxide active material. Examples of the metal active material include simple metals and metal alloys. Examples of the metal element contained in the metal active material include Si, Sn, In, Al and the like. The metal alloy is preferably an alloy containing the above metal element as a main component. Examples of Si alloys include Si—Al alloys, Si—Sn alloys, Si—In alloys, Si—Ag alloys, Si—Pb alloys, Si—Sb alloys, Si—Bi alloys, and Si—. Examples thereof include Mg-based alloys, Si—Ca-based alloys, Si—Ge-based alloys, and Si—Pb-based alloys. For example, the Si—Al alloy means an alloy containing at least Si and Al, and may be an alloy containing only Si and Al, or an alloy containing yet another metal element. good. The same applies to alloys other than Si—Al alloys. The metal alloy may be a two-component alloy or a three-component or higher multi-component alloy. On the other hand, examples of the carbon active material include mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), hard carbon, soft carbon and the like. Examples of the oxide active material include lithium titanate such as _{Li 4} Ti ₅ O _12.

Examples of the shape of the negative electrode active material include particulate matter. The average particle size (D ₅₀ ) of the negative electrode active material is, for example, 10 nm or more, and may be 100 nm or more. On the other hand, the average particle size (D ₅₀ ) of the negative electrode active material is, for example, 50 μm or less, and may be 20 μm or less. The content of all the active materials (negative electrode active materials) contained in the negative electrode layer is, for example, 60 wt% or more, preferably 70 wt% or more. On the other hand, the content of the negative electrode active material contained in the negative electrode layer is, for example, 99 wt% or less, and may be 95 wt% or less. The solid electrolyte, the binder, and the conductive material can be the same as those described in the above section “(b) Positive electrode layer”, and thus the description thereof is omitted here.

The thickness of the negative electrode layer can be, for example, 0.1 μm or more and 1000 μm or less.

(D) Solid electrolyte layer It is formed between the negative electrode layer and the positive electrode layer. The solid electrolyte layer is a layer containing a solid electrolyte. The solid electrolyte layer may contain a binder, if necessary.

The content of the solid electrolyte in the solid electrolyte layer is, for example, 10% by weight or more, and may be 50% by weight or more. On the other hand, the content of the solid electrolyte is, for example, 100% by weight or less. The solid electrolyte and the binder can be the same as those described in the above section “(b) Positive electrode layer”, and thus the description thereof is omitted here.

The thickness of the solid electrolyte layer can be, for example, 0.1 μm or more and 1000 μm or less.

(2) Jig The jig may be a member that can apply a restraining pressure to a plurality of laminated bodies in the thickness direction.

The jig preferably has a shape that allows the side surfaces of the plurality of laminates to be filled with the photocurable resin in the second step described later. For example, as shown in FIGS. 1A to 1C, it is preferable to arrange the pressing plate 20 as a jig so as to apply a restraining pressure to the plurality of laminated bodies 10 from both sides in the thickness direction.

The material of the jig may be any material having rigidity enough to hold a plurality of laminated bodies in the thickness direction and apply a restraining pressure, and can be appropriately selected according to the shape of the jig. .. In the third step, the photocurable resin is cured by irradiating the photocurable resin filled on the side surface of the plurality of laminates with light while applying a restraining pressure using a jig. Therefore, it is preferable that the jig material has light transmittance with respect to the light irradiated in the third step. Having light transmittance means that the transmittance of the main wavelength of the light irradiated in the third step is, for example, 50% or more. The transmittance is preferably 60% or more, and preferably 70% or more, from the viewpoint of improving the sensitivity of the photocurable resin. Examples of the material of such a jig include polytetrafluoroethylene (PTFE) (trade name: Teflon (registered trademark), manufactured by DuPont), polypropylene (PP) and the like.

The jig is usually removed after the third step. Therefore, it is preferable that at least the surface of the jig in contact with the laminated body is subjected to a mold release treatment. This is because the jig can be satisfactorily peeled off from the laminated body, and the jig can be made into a jig having excellent mold releasability. The mold release process can be the same as a generally known process. Specific examples of the mold release treatment include fluorine coating.

(3) Laminated Battery A laminated battery is composed of a plurality of laminated bodies laminated in the thickness direction. The first laminated body to the Nth laminated body are sequentially formed along the thickness direction of the laminated battery. N means the total number of laminated bodies contained in the laminated battery, and may be, for example, 3 or more, 10 or more, 30 or more, or 50 or more. On the other hand, N is, for example, 200 or less, may be 150 or less, or may be 100 or less.

2. Second Step The second step is a step of filling the side surfaces of the plurality of laminated bodies with a photocurable resin.

The second step may be a step in which the side surfaces of the plurality of laminates can be filled with the photocurable resin. Among them, the second step is a step in which only the side surfaces of the plurality of laminates are filled with the photocurable resin. It may be a step of filling the side surface of the laminated body and the surface of the laminated body located on the outermost side of the laminated battery with a photocurable resin.

The method of filling the side surfaces of the plurality of laminates with the photocurable resin is not particularly limited, but for example, as shown in FIG. 2A, the photocurable resin contained in the container is mixed with the plurality of laminates. A method of pouring and filling on the side surface, a method of discharging and filling the side surface of a plurality of laminated bodies with a photocurable resin using a dispenser as shown in FIG. As shown, a method of pouring a photocurable resin contained in a container onto the side surface of a plurality of laminated bodies and filling the container with a scraper can be mentioned.

The second step can be performed in a predetermined atmosphere. Examples of the atmosphere in which the second step is performed include an atmospheric pressure atmosphere, a reduced pressure atmosphere, and a pressurized atmosphere, and among them, an atmospheric pressure atmosphere or a reduced pressure atmosphere is preferable. The reduced pressure atmosphere is not particularly limited, but is preferably a vacuum pressure atmosphere, for example. By performing the second step in the above atmosphere, the side surfaces of the plurality of laminates can be satisfactorily filled with the photocurable resin. Examples of the method of performing the second step in the above atmosphere include a method of arranging a plurality of laminated bodies in the chamber, evacuating the inside of the chamber, and opening the atmospheric pressure.

The photocurable resin used in the second step will be described. Here, the "photocurable resin" refers to a resin having a property of being cured by light irradiation. Further, in the present disclosure, it refers to a state before being cured by light irradiation. That is, the photocurable resin is in a state of having a degree of fluidity that reaches the side surfaces of the laminate when poured into the side surfaces of the laminate.

The viscosity of the photocurable resin at the time of filling in the second step, that is, the viscosity immediately before filling is 1000 mPa · s or more and 25000 mPa · s or less. The viscosity of the photocurable resin is, for example, 1300 mPa · s or more, and may be 1400 mPa · s or more. On the other hand, the viscosity of the photocurable resin is, for example, 22000 mPa · s or less, and may be 20000 mPa · s or less. When the viscosity of the photocurable resin at the time of filling is within the above range, the photocurable resin can be sufficiently spread on the side surfaces of the plurality of laminates. Specifically, when the viscosity of the photocurable resin has the above lower limit, the photocurable resin can be filled only on the side surfaces of the plurality of laminates, and excessive filling can be suppressed. On the other hand, when the viscosity of the photocurable resin has the above upper limit, it is possible to sufficiently fill the gaps between the layers constituting the laminated body with the photocurable resin on the side surfaces of the plurality of laminated bodies.

As shown in FIG. 4A, for example, the photocurable resin can be adjusted to a viscosity within the above range by heating the photocurable resin with a heater. The heating means is not particularly limited as long as it can heat the photocurable resin, in addition to the means using a heater as shown in FIG. 4A. The temperature at which the photocurable resin is heated can be appropriately determined depending on the type of the photocurable resin. The specific heating temperature is, for example, a temperature higher than room temperature (25 ° C.), may be 40 ° C. or higher, may be 50 ° C. or higher, or may be 60 ° C. or higher. On the other hand, the heating temperature is, for example, 100 ° C. or lower, 90 ° C. or lower, or 80 ° C. or lower.

The photocurable resin has a viscosity at room temperature (25 ° C.) of, for example, 2000 mPa · s or more and 80,000 mPa · s or less. The viscosity of the specific photocurable resin at room temperature (25 ° C.) may be, for example, 10000 mPa · s or more, 20000 mPa · s or more, or 25000000 mPa · s or more. On the other hand, the viscosity of the photocurable resin at room temperature (25 ° C.) may be, for example, 70,000 mPa · s or less, 60,000 mPa · s or less, or 50,000 mPa · s or less. When the viscosity of the photocurable resin at room temperature (25 ° C.) is within the above range, the performance of the laminated battery is deteriorated due to the photocurable resin entering the gaps between the layers constituting the laminated body in the second step. It can be suppressed.

Examples of such a photocurable resin include a resin that photocures when exposed to light having a wavelength of 200 nm or more and 700 nm or less, and a resin that can be adjusted to the above-mentioned viscosity is preferable. Specific examples thereof include imide resin, silicone resin, urethane resin and the like. In the second step, a photopolymerization initiator, a photopolymerization accelerator, a sensitizer, and the like may be contained in addition to the photocurable resin, if necessary.

The filling amount and filling speed of the photocurable resin in the second step can be appropriately adjusted according to the configuration of the laminated battery, the temperature and viscosity of the photocurable resin, the filling method, and the like. Omit.

3. 3. Third Step The third step is a step of irradiating the photocurable resin with light to cure the photocurable resin.

The method of irradiating the photocurable resin with light in the third step is not particularly limited as long as it can be cured by irradiating the photocurable resin with light. For example, as shown in FIGS. 2 to 4, a method of irradiating light by irradiating a light source on the side surface of the laminated body can be mentioned. Further, although not shown, the laminated body may be irradiated with light via a jig. In this case, the jig preferably has light transmission to the emitted light. Since the light transmission of the jig has been described in the above section "1. First step (2) Jig", the description here is omitted.

The type of the light source to be irradiated in the third step can be appropriately determined according to the type of the photocurable resin to be filled on the side surface of the laminated body. Specific types of light sources include energy rays such as ultraviolet rays.

The present disclosure is not limited to the above embodiment. The above embodiment is an example, and any object having substantially the same structure as the technical idea described in the claims of the present disclosure and exhibiting the same effect and effect is the present invention. Included in the technical scope of the disclosure.

The present disclosure will be described in more detail with reference to Examples below.

[Example]
As shown in FIG. 1A, a laminated battery having a plurality of laminated bodies having a positive electrode current collector layer 41, a positive electrode layer 1, a solid electrolyte layer 3, a negative electrode layer 2 and a negative electrode current collector layer 42 in this order in the thickness direction. I prepared 100. Next, a pressing plate 20 (fluororesin material) was arranged as a jig on the surface of the laminated battery 100 in the thickness direction x to apply a restraining pressure (first step). Next, as shown in FIG. 2A, a photocurable resin (acrylic resin, viscosity: 20000 mPa · s) heated to 60 ° C. was laminated in an atmospheric pressure atmosphere at room temperature (25 ° C.). It was poured from the side surface of the body and the side surface of the laminated body was filled (second step). Then, as shown in FIGS. 2 (b) and 2 (c), the side surface of the laminated body was irradiated with UV to cure the photocurable resin (third step).

[evaluation]
When the cross section of the obtained laminated battery was confirmed, it was possible to sufficiently fill the side surface of the laminated body with the resin and suppress the excessive filling of the resin into the inside of the laminated body.

1 ... Positive electrode layer 2 ... Negative electrode layer 3 ... Solid electrolyte layer 4 ... Current collector layer 41 ... Positive electrode current collector layer 42 ... Negative electrode current collector layer 5 ... Bipolar electrode layer 10 ... Laminated body 20 ... Jig (pressing plate)
30'... Photocurable resin 30 ... Cured product 100 ... Laminated battery

Claims (1)

A method for manufacturing a laminated battery having a plurality of laminates having a positive electrode current collector layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector layer in this order in the thickness direction.
The first step of applying a restraining pressure to the plurality of laminated bodies using a jig in the thickness direction, and
A second step of filling the side surfaces of the plurality of laminates with a photocurable resin, and
It has a third step of irradiating the photocurable resin with light to cure the photocurable resin.
A method for producing a laminated battery, wherein in the second step, the viscosity of the photocurable resin at the time of filling is 1000 mPa · s or more and 25000 mPa · s or less.

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