All-solid-state battery manufacturing apparatus and all-solid-state battery manufacturing method

An all-solid-state battery manufacturing apparatus disclosed herein includes a transport apparatus, a press roller, and an adhesive provision apparatus. The transport apparatus transports an active material layer. The press roller has a foil attachment surface, which is a cylindrical surface to which the current collection foil is to be attached. The press roller rotates and moves the current collection foil attached to the foil attachment surface to the surface of the active material layer being transported by the transport apparatus and presses the current collection foil and the active material layer between the press roller and the transport apparatus. The adhesive provision apparatus is provided on a movement path of the current collection foil rotated and moved by the foil attachment surface of the press roller, and provides an adhesive to the current collection foil attached to the press roller.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present specification claims priority on the basis of Japanese Patent Application No. 2020-118341 filed on Jul. 9, 2020, the contents of which are incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present teaching relates to an all-solid-state battery manufacturing apparatus and an all-solid-state battery manufacturing method.

2. Description of the Related Art

Secondary batteries have widely been used as portable power sources for personal computers, mobile telephones, and the like, and as vehicle driving power sources for EVs (electric vehicles), HVs (hybrid vehicles), PHVs (plug-in hybrid vehicles), and the like. As one example of a secondary battery, development of an all-solid-state battery using a solid electrolyte instead of a liquid electrolyte has been progressing. In an all-solid-state battery, a first current collector, a first active material layer, a solid electrolyte layer, a second active material layer, and a second current collector are stacked in the stated order. If the relative positions of the multiple stacked layers shift, there is a possibility that the battery performance will change. Accordingly, in order to suppress shifting of the positions of the multiple layers, a technique has been proposed in which two layers that are adjacent to each other are adhered. For example, an all-solid-state battery disclosed in Japanese Patent Application Publication No. 2017-204377 is manufactured by adhering a first current collector and a first active material layer using a thermoplastic resin.

SUMMARY

According to the conventional all-solid-state battery manufacturing method, multiple layers are bonded by heating and compressing the multiple layers in a stacking direction using a flat plate in a state in which adhesive has been arranged between the layers to be adhered. With this method, it is difficult to shorten the amount of manufacturing time. Accordingly, a method according to which multiple layers can be adhered more suitably has been desired.

A typical object of the present teaching is to provide an all-solid-state battery manufacturing apparatus and an all-solid-state battery manufacturing method which enable multiple layers constituting a battery to be adhered more appropriately.

In order to realize the object, an all-solid-state battery manufacturing apparatus according to an aspect disclosed here is a manufacturing apparatus for manufacturing an all-solid-state battery in which a current collection foil and an active material layer are stacked, the manufacturing apparatus including: a transport apparatus configured to transport the active material layer supported on a support surface; a press roller that has a foil attachment surface, which is a cylindrical surface to which the current collection foil supplied from the outside is to be attached, and that is configured to rotate and move the current collection foil attached to the foil attachment surface to a surface of the active material layer being transported by the transport apparatus by rotating using a central axis of the cylindrical surface as a rotational axis, and to press the current collection foil and the active material layer in a thickness direction between the press roller and the support surface of the transport apparatus; and an adhesive provision apparatus that is provided on a movement path of the current collection foil rotated and moved by the foil attachment surface of the press roller, and that is configured to provide an adhesive to the current collection foil attached to the press roller.

With the all-solid-state battery manufacturing apparatus according to the present disclosure, the current collection foil provided with the adhesive and the active material layer can be stacked and pressed (compressed) while the current collection foil is rotated and moved by the press roller. Accordingly, it is possible to adhere the current collection foil and the active material layer in a shorter amount of time compared to the case of pressing the current collection foil and the active material layer using a flat plate or the like.

In one desirable aspect of the manufacturing apparatus disclosed herein, the adhesive provision apparatus includes an adhesive roller. The adhesive roller includes an adhesive contact surface, which is a cylinder surface that comes into contact with the adhesive. The adhesive roller adjusts a thickness of the adhesive on the current collection foil attached to the foil attachment surface of the press roller by rotating using an axis parallel to the rotational axis of the press roller as a rotational axis.

If the current collection foil and the active material layer are pressed using the flat plate, it is possible to reduce the thickness of the adhesive between the current collection foil and the active material layer by extending the amount of pressing time. However, as described above, it is difficult to shorten the amount of manufacturing time if the flat plate is used. Also, if the current collection foil and the active material layer are simply pressed using the press roller, the amount of time for which the pressing pressure is applied is shortened, and therefore there is also a possibility that the thickness of the adhesive between the current collection foil and the active material layer will not decrease and the shape of the stacked body of the all-solid-state battery will be disturbed. If the shape of the stacked body is disturbed, deterioration of the battery performance and the like will occur in some cases as well. In contrast to this, due to the thickness of the adhesive attached on the current collection foil being adjusted (reduced) in advance by the adhesive roller, the current collection foil and the active material layer are adhered in a short amount of time and the shape of the stacked body is also less likely to be disturbed. Accordingly, the current collection foil and the active material layer are adhered more suitably.

In one desirable aspect of the manufacturing apparatus disclosed herein, the adhesive provision apparatus further includes a supply apparatus that supplies adhesive to the adhesive contact surface of the adhesive roller. The adhesive roller adjusts the thickness of the adhesive while transferring the adhesive supplied to the adhesive contact surface by the supply apparatus to the current collection foil attached to the foil attachment surface. In this case, the step of providing the adhesive to the current collection foil and the step of adjusting the thickness of the adhesive on the current collection foil are performed at the same time (in parallel). Accordingly, the current collection foil and the active material layer are adhered more efficiently. However, the adhesive may also be provided to the current collection foil using a method other than transfer using the adhesive roller (e.g., a method such as dripping, coating, or spraying).

In one desirable aspect of the manufacturing apparatus disclosed herein, the adhesive is a photocurable adhesive that is cured due to a curing light being emitted thereto. The manufacturing apparatus further includes a curing light emission unit configured to emit the curing light to the adhesive on the current collection foil attached to the press roller. In this case, unlike the case of using a hot melt that is melted by being heated as the adhesive, there is no need to heat the adhesive, and therefore the manufacturing efficiency is further improved and there is no adverse effect on the members of the all-solid-state battery due to heat. Furthermore, even if the temperature of the all-solid-state battery rises during use, the adhesive is not melted, and therefore the shape is not likely to change either. Accordingly, the current collection foil and the active material layer are adhered more suitably. However, it is also possible to use a hot melt or the like as the adhesive.

In a desirable aspect of the manufacturing apparatus disclosed herein, at least a portion of the adhesive roller is made of a material through which the curing light passes. A curing light emission unit emits the curing light through the adhesive roller to the adhesive on the current collection foil attached to the press roller. In this case, the curing light is emitted to the adhesive while the thickness of the adhesive on the current collection foil is adjusted by the adhesive roller. Accordingly, the degree of freedom in the arrangement of the apparatuses improve, and the current collection foil and the active material layer are adhered more efficiently. However, it is also possible to emit the curing light to the adhesive without allowing the curing light to pass through the adhesive roller.

In one desirable aspect of the manufacturing apparatus disclosed herein, the press roller includes a plurality of ventilation holes that extend from the foil attachment surface to the interior. The press roller attaches the current collection foil to the foil attachment surface by suctioning a gas from the ventilation holes to the interior. In this case, the press roller can easily and suitably attach the current collection foil to the foil attachment surface.

In one desirable aspect of the manufacturing apparatus disclosed herein, a viscosity of the adhesive when provided to the current collection foil is 100 mPa·s to 5000 mPa·s. In this case, the adhesive is suitably provided to the current collection foil and adhesion of the current collection foil and the active material layer is also performed suitably. Also, in the case where the surface of the current collection foil is coated with carbon, if the viscosity of the adhesive is too low, there is a possibility that the adhesive will excessively permeate the carbon layer and the current collection foil and the active material layer will not be sufficiently adhered. Conversely, if the viscosity of the adhesive is too high, there is a possibility that the adhesive will not be likely to permeate the carbon layer and the thickness of the adhesive will not decrease sufficiently. Accordingly, if the surface of the current collection foil is coated with carbon, the viscosity of the adhesive may be 500 mPa·s to 1500 mPa·s. In this case, it is possible to obtain a favorable adhesive thickness and adhesiveness.

An all-solid-state battery manufacturing method according to one aspect disclosed herein is a manufacturing method for manufacturing an all-solid-state battery in which a current collection foil and an active material layer are stacked, the manufacturing method including: a current collection foil attachment step of attaching the current collection foil to a foil attachment surface of a press roller that includes the foil attachment surface, which is a cylindrical surface, and that is configured to rotate using a central axis of the cylindrical surface as a rotational axis; an adhesive provision step of providing an adhesive on the current collection foil attached to the foil attachment surface; and a pressing step of rotating and moving the current collection foil attached to the foil attachment surface to a surface of the active material layer being transported by a transport apparatus by rotating the press roller, and pressing the current collection foil and the active material layer in a thickness direction between the press roller and the transport apparatus.

According to the all-solid-state battery manufacturing method according to the present disclosure, the current collection foil provided with the adhesive and the active material layer can be stacked and pressed (compressed) while the current collection foil is rotated and moved using a press roller. Accordingly, it is possible to adhere the current collection foil and the active material layer in a shorter amount of time compared to the case of pressing the current collection foil and the active material layer using a flat plate or the like.

One favorable aspect of the manufacturing method disclosed herein further includes a thickness adjustment step. In the thickness adjustment step, the thickness of the adhesive is adjusted by bringing an adhesive contact surface of an adhesive roller that has the adhesive contact surface, which is a cylinder surface, and that is configured to rotate using an axis parallel to the rotational axis of the press roller as the rotational axis into contact with the adhesive on the current collection foil attached to the foil attachment surface. In this case, as described above, the thickness of the adhesive attached on the current collection foil is adjusted in advance using the adhesive roller, and thereby the current collection foil and the active material layer are adhered in a short amount of time, and the shape of the stacked body is less likely to be disturbed.

In one suitable aspect of the manufacturing method disclosed herein, the adhesive provision step and the thickness adjustment step are performed at the same time by transferring the adhesive supplied to the adhesive contact surface of the adhesive roller to the current collection foil attached to the foil attachment surface. In this case, the current collection foil and the active material layer are adhered more efficiently.

In one desirable aspect of the manufacturing method disclosed herein, the adhesive is a photocurable adhesive that is cured due to a curing light being emitted thereto, and a photocurable adhesive that is cured due to a curing light such as ultraviolet rays and/or visible light rays being emitted thereto is desirable. The manufacturing method further includes a curing light emission step of emitting the curing light to the adhesive. In this case, there is no need to heat the adhesive, and therefore the manufacturing efficiency further improves, and there is no adverse effect on the material of the all-solid-state battery due to heat. Furthermore, the shape is less likely to change due to heating of the all-solid-state battery when in use.

In one favorable aspect of the manufacturing method disclosed herein, a viscosity of the adhesive when provided to the current collection foil is 100 mPa·s to 5000 mPa·s. Also, if the surface of the current collection foil is coated with carbon, the viscosity of the adhesive may be 500 mPa·s to 1500 mPa·s. In this case, as described above, the current collection foil and the active material layer are adhered more suitably.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, one typical embodiment of the present disclosure will be described in detail with reference to the drawings. Unless specifically mentioned in the present specification, items that are needed for implementation (e.g., configurations of the all-solid-state battery, etc.) can be understood as items to be designed by a person skilled in the art based on the conventional techniques of the field. The all-solid-state battery manufacturing apparatus and manufacturing method disclosed herein can be implemented based on the content disclosed in the present specification and common technical knowledge in the field. It should be noted that in the following drawings, members and portions that exhibit the same effects are denoted by the same reference numerals and described. Also, the dimensional relationships (length, width, thickness, etc.) in the drawings do not reflect the actual dimensional relationships.

First, an overall configuration of an all-solid-state lithium ion secondary battery (hereinafter referred to simply as an “all-solid-state battery” in some cases as well), which is one example of an all-solid-state battery manufactured using the manufacturing apparatus and the manufacturing method illustrated in the present disclosure, will be described. However, the all-solid-state battery to which the manufacturing method of the present disclosure is to be applied is not limited to an all-solid-state lithium ion secondary battery. That is, the all-solid-state battery may also be an all-solid-state battery in which a metal ion other than a lithium ion is used as a charge carrier, such as a sodium ion secondary battery, a magnesium ion secondary battery, or the like.

The all-solid-state battery in the present disclosure is manufactured by stacking multiple battery units, which are stacked bodies. The battery unit includes a positive electrode current collector, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector.

The solid electrolyte layer includes at least a solid electrolyte. Examples of solid electrolytes include sulfide-based solid electrolytes and oxide-based solid electrolytes. Examples of sulfide-based solid electrolytes include glass or glass ceramics that are Li2S—SiS2-based, Li2S—P2S3-based, Li2S—P2S5-based, Li2S—GeS2-based, Li2S—B2S3-based, or the like. Examples of oxide-based solid electrolytes include various oxides having a NASICON structure, a garnet-type structure, or a perovskite-type structure. The solid electrolyte is, for example, in the form of particles. The solid electrolyte layer contains a binder (binding material) such as butadiene rubber.

The positive electrode active material layer includes at least a positive electrode active material. The positive electrode active material layer desirably further includes a solid electrolyte, and may further include a conductive material, a binder, or the like. For example, known conductive materials such as VGCF and acetylene black can be used as the conductive material of the positive electrode active material layer. For example, a fluorine-containing resin such as polyvinylidene fluoride or the like can be used as the binder of the positive electrode active material layer. Various compounds that have been conventionally used in this type of battery can be used as the positive electrode active material. Examples of the positive electrode active material include composite oxides with layered structures, such as LiCoO2and LiNiO2, composite oxides with spinel structures, such as Li2NiMn3O8and LiMn2O4, and composite compounds with olivine structures, such as LiFePO4. The same type of material as the solid electrolyte contained in the solid electrolyte layer can be used as the solid electrolyte in the positive electrode active material layer. The positive electrolyte active material is, for example, in the form of particles.

The negative electrode active material layer includes at least a negative electrode active material. The negative electrode active material layer desirably further includes a solid electrolyte, and may further include a conductive material, a binder, or the like. For example, a known conductive material such as acetylene black can be used as the conductive material of the negative electrode active material layer. For example, a fluorine-containing resin such as polyvinylidene fluoride can be used as the binder of the negative electrode active material layer. Various compounds that have been conventionally used in this type of battery can be used as the negative electrode active material. Examples of the negative electrode active material include carbon-based negative electrode active materials such as graphite, mesocarbon microbeads, and carbon black. Also, examples of the negative electrode active material include a negative electrode active material in which silicon (Si) or tin (Sn) is used as a constituent element. The same type of material as the solid electrolyte contained in the solid electrolyte layer can be used as the solid electrolyte in the negative electrode active material layer. The negative electrolyte active material is, for example, in the form of particles.

A positive electrode current collector that is used as a positive electrode current collector of this type of battery can be used without any particular restriction as the positive electrode current collector. Typically, it is desirable that the positive electrode current collector is made of a metal that has a favorable conductivity. For example, the positive electrode current collector may also be constituted by a metal material such as aluminum, nickel, chromium, gold, platinum, titanium, zinc, and stainless steel. It should be noted that the positive electrode current collector of the present embodiment is a metal foil (current collection foil), and has a surface that is coated with a carbon layer having a thickness of about 3 μm. A negative electrode current collector that is used as a negative electrode current collector of this type of battery can be used without any particular restriction as the negative electrode current collector. Typically, it is desirable that the negative electrode current collector is made of a metal that has a favorable conductivity. For example, copper (copper foil) or an alloy consisting mainly of copper; aluminum, nickel, iron, titanium, zinc, or the like can be used as the negative electrode current collector.

Manufacturing Apparatus

An all-solid-state battery manufacturing apparatus1in the present embodiment will be described with reference toFIG.1. The manufacturing apparatus1manufactures the battery unit of the all-solid-state battery by adhering a current collection foil2to an active material layer3using an adhesive5. In one example, in the manufacturing apparatus1of the present embodiment, the current collection foil2, which is a positive electrode current collector, is stacked on and adhered to the active material layer3, which is a positive electrode active material layer. However, the manufacturing apparatus1may also be used in the case of adhering the current collection foil, which is a negative electrode current collector, to a negative electrode active material layer. Also, hereinafter, in order to simplify the description, the current collection foil2is stacked on (adhered to) the active material layer3in a state in which the active material layer3has not yet been stacked on another layer (e.g., at least one of a solid electrolyte layer, an opposing electrode active material layer, and an opposing electrode current collector). However, the manufacturing apparatus1may also stack and adhere the current collection foil2on the surface of the active material layer3that has already been stacked on another layer.

The manufacturing apparatus1of the present embodiment includes a transport apparatus10, a press roller20, a supply/cutting apparatus30, an adhesive provision apparatus50, and a curing light emission unit60.

The transport apparatus10transports the active material layer3along a transport direction CD in a state in which the active material layer3is supported on a support surface11. The support surface11may be, for example, a conveyor belt or the like. Although the details will be described later, the support surface11is used also as a pressing surface that presses the current collection foil2and the active material layer3. Accordingly, it is desirable that the support surface11is made of a material having an appropriate degree of rigidity. In the present embodiment, multiple active material layers3formed at a uniform size are transported continuously by the transport apparatus10. Accordingly, the all-solid-state battery manufacturing time is easily shortened. Also, in the present embodiment, one (bottom surface) of a pair of wide surfaces of the active material layer3formed into a flat plate shape is supported by the support surface11. As a result, the other (hereinafter referred to as “outer surface”) of the pair of wide surfaces faces upward. However, as described before, the active material layer3transported by the transport apparatus10may be stacked on another layer. In this case, the other layer stacked on the active material layer3comes into contact with the support surface11and the active material layer3faces upward.

The press roller20is a member with an approximately tubular outer shape or an approximately cylindrical outer shape. In other words, the outer circumferential surface of the press roller20is a cylinder surface. The press roller20attaches the current collection foil2that is supplied from the outside to the foil attachment surface21, which is a cylindrical surface. The press roller20rotates in an arrow direction PD using the central axis of the cylindrical surface (foil attachment surface21) as the rotational axis25. The rotational axis25extends in a horizontal direction, orthogonal to the transport direction of the active material layer3transported by the transport apparatus10.

The press roller20in the present embodiment includes multiple ventilation holes23that extend from the foil attachment surface21, which is the cylindrical surface, to the interior. Although many ventilation holes23are provided on the foil attachment surface21, only a portion of the multiple ventilation holes23are indicated by the dotted lines inFIG.1. The press roller20attaches the current collection foil2to the foil attachment surface21by suctioning a gas (air) from the ventilation holes23into the interior.

It should be noted that the press roller20(or the control unit of the manufacturing apparatus1) in the present embodiment switches between attachment of the current collection foil2to the foil attachment surface21and separation of the current collection foil2from the foil attachment surface21by switching between suction of the gas from the respective ventilation holes23and stopping of suction (or discharge) according to the position. Specifically, the press roller20in the present embodiment discharges the air to the outside from the ventilation hole23which has rotated to the lowest position (i.e., the ventilation hole23at the closest position to the transport apparatus10) among the many ventilation holes23provided in the peripheral direction. Also, the press roller20suctions gas into the interior from the ventilation holes23located in at least region in the foil attachment surface21where the current collection foil2is to be attached.

However, it is also possible to change the principle for attaching the current collection foil2to the foil attachment surface21. For example, the current collection foil2may also be attached to the foil attachment surface21using static electricity or the like. Also, if the adhesive force between the current collection foil2and the foil attachment surface21is weaker than the attachment force (to be described in detail later) of the adhesive5between the current collection foil2and the active material layer3, the press roller20need not include the configuration of separating the current collection foil2attached to the foil attachment surface21.

The supply/cutting apparatus30supplies the current collection foil2from the outside to the press roller20. Also, the supply/cutting apparatus30in the present embodiment cuts the current collection foil2having an elongated shape to a predetermined length and supplies the cut current collection foil2to the press roller20. In the present embodiment, the supply/cutting apparatus30is provided above the press roller20. The current collection foil2that was cut and supplied to the upper portion of the press roller20attaches to the foil attachment surface21.

The supply/cutting apparatus30in the present embodiment supplies the current collection foil2to the upper portion of the press roller20by rotating a pair of rollers in a state in which the current collection foil2is sandwiched between the pair of rollers. Also, a cutter is provided on at least one of the pair of rollers. The pair of rollers rotate, and when the length of the current collection foil2to be supplied to the press roller20side reaches a predetermined length, the current collection foil2is cut by the cutter. The supply/cutting apparatus30continuously supplies the current collection foils2of the predetermined length to the press roller20. The operation of the supply/cutting apparatus30is controlled by the control unit of the manufacturing apparatus1. It should be noted that it goes without saying that the configuration of the supply/cutting apparatus30can be changed.

The press roller20rotates and moves the current collection foil2that was supplied by the supply/cutting apparatus30and attached to the foil attachment surface21from the upper portion to the outer surface of the active material layer3transported by the transport apparatus10at the lower position. At this time, the adhesive5(to be described in detail later) provided on the current collection foil2is sandwiched between the current collection foil2and the active material layer3. Furthermore, the press roller20presses the current collection foil2and the active material layer3in the thickness direction (the vertical direction inFIG.1) between the press roller20and the support surface11of the transport apparatus10. That is, the manufacturing apparatus1can stack and press the current collection foil2and the active material layer3while rotating and moving the current collection foil2using the press roller20. Accordingly, it is possible to stack (adhere) the current collection foil2and the active material layer3in a shorter amount of time compared to the case of pressing the active material layer using a flat plate or the like.

The adhesive provision apparatus50is provided on the movement route (in the present embodiment, the movement route from the upper portion to which the current collection foil2is supplied to the lower portion at which the current collection foil2is stacked on the active material layer3) of the current collection foil2that is rotated and moved by the foil attachment surface21of the press roller20. The adhesive provision apparatus50provides the adhesive5to the current collection2attached to the press roller20.

The adhesive provision apparatus50in the present embodiment includes an adhesive roller51. The adhesive roller51is a member with an approximately cylindrical outer shape or an approximately circular columnar outer shape. In other words, the outer circumferential surface of the adhesive roller51is a cylindrical surface. The cylindrical surface of the adhesive roller51is an adhesive contact surface52that comes into contact with the adhesive5. The adhesive roller51rotates in the direction of the arrow AD using the central axis of the cylindrical surface (adhesive contact surface52) as the rotational axis55. The rotational axis55of the adhesive roller51is parallel to the rotational axis25of the press roller20. Also, the rotation direction PD of the press roller20is the direction opposite to the rotation direction AD of the adhesive roller51. The distance between the adhesive contact surface52of the adhesive roller51and the foil attachment surface21of the press roller20is set to a predetermined distance according to the adjustment amount of the thickness of the later-described adhesive5.

The adhesive provision apparatus50includes a supply apparatus57. The supply apparatus57supplies the adhesive5to the adhesive contact surface52of the adhesive roller51. Various methods (e.g., dripping, coating, spraying, etc.) can be used as the method for supplying the adhesive5to the adhesive contact surface52using the supply apparatus57. The adhesive5supplied from the supply apparatus57to the adhesive contact surface52rotates and moves in the arrow AD direction and is transferred onto the current collection foil2attached to the foil attachment surface21of the press roller20. The supply location, supply amount, and supply timing for supplying the adhesive from the supply apparatus57to the adhesive contact surface52are suitably adjusted. As a result, a suitable amount of the adhesive5is transferred to a suitable position of the current collection foil2that is being rotated and moved by the press roller20.

With the manufacturing apparatus1of the present embodiment, the thickness of the adhesive5on the current collection foil2is adjusted due to the adhesive contact surface52of the adhesive roller51coming into contact with the adhesive5provided on the current collection foil2. Since the rotation direction PD of the press roller20is the opposite direction to the rotation direction AD of the adhesive roller51, the thickness of the adhesive5on the current collection foil2is suitably adjusted without being adversely influenced by friction or the like. In one example, in the present embodiment, the thickness of the adhesive5on the current collection foil2is adjusted to 2 μm or less by the adhesive roller51. Thereafter, the current collection foil2and the active material layer3is pressed in the thickness direction by the press roller20in a state in which the adhesive5whose thickness was adjusted in advance is sandwiched between the current collection foil2and the active material layer3. Accordingly, even if the current collection foil2and the active material layer3are pressed by the press roller20, according to which the time of applying the pressing pressure is likely to be shortened, the thickness of the adhesive5is likely to reach a suitable thickness or less. As a result, the likelihood that the shape of the battery unit (stacked body) of the all-solid-state battery will be disturbed due to the influence of the thickness of the adhesive5. Accordingly, with the manufacturing apparatus1of the present disclosure, the current collection foil2and the active material layer3are suitably attached in a short amount of time.

Also, the adhesive roller51in the present embodiment transfers the adhesive5to the current collection foil2of the foil attachment surface21while adjusting the thickness of the transferred adhesive5. That is, in the present embodiment, the step of providing the adhesive5to the current collection foil2and the step of adjusting the thickness of the adhesive5on the current collection foil2are performed at the same time. Accordingly, the current collection foil2and the active material layer3are adhered more efficiently.

The adhesive5is a photocurable adhesive that is cured due to a curing light being emitted thereto, and is desirably a photocurable adhesive that is cured due to a curing light such as ultraviolet rays and/or visible light rays being emitted thereto. In one example, in the present embodiment, the adhesive5including a photocurable acrylic compound is used. When an adhesive5that includes a photoradically-curable acrylic compound is used, an adhesive whose cured surface has pressure-sensitive adhesion at room temperature is desirable. However, another photocurable adhesive (e.g., at least one of a cationic-photocurable adhesive that is epoxy-based or the like, a silicon-based light-and-moisture-curable adhesive, and the like) may also be used. When a photocurable adhesive is used, there is no need to heat the adhesive5, unlike the case where a hot melt is used as the adhesive. Therefore, the manufacturing efficiency further improves and there is no adverse effect on the member of the all-solid-state battery due to heat. Furthermore, even if the temperature of the all-solid-state battery rises during use, the adhesive5is not melted, and therefore the shape is not likely to change either. Accordingly, the current collection foil2and the active material layer3are adhered more suitably.

The curing light emission unit60emits the curing light to the adhesive5. The adhesive5in the present embodiment starts a curing reaction when the curing light is emitted thereto from the curing light emission unit60, and the adhesive5is sufficiently cured after the pressing of the current collection foil2and the active material layer3by the press roller20.

Specifically, at least a portion of the adhesive roller51in the present embodiment is made of a material through which the curing light passes. The curing light emission unit60emits the curing light through the adhesive roller51to the adhesive5on the current collection foil attached to the press roller20. Accordingly, the curing light is emitted to the adhesive5while the thickness of the adhesive5on the current collection foil2is adjusted by the adhesive roller51. Accordingly, the degree of freedom in the arrangement of the apparatuses improves and the current collection foil2and the active material layer3are adhered more efficiently. Furthermore, if an adhesive5including a photoradically-curable acrylic compound is used and photocured, polymerization is hindered by the oxygen in the air, and it is known that this becomes prominent when the thickness is about several μms. On the other hand, as in the present embodiment, by using a configuration in which a material through which a curing light passes, or desirably, a material through which ultraviolet light and/or visible light passes is used as the material of the rollers51, and the curing light is emitted to the adhesive5at a location with which the roller51is in contact, it is possible to favorably cure the adhesive5without causing inhibition of polymerization, even if an adhesive5that includes a photoradically-curable acrylic compound is used.

The viscosity of the adhesive5when provided to the current collection foil2is 100 mPa·s to 5000 mPa·s. In this case, the adhesive5is suitably provided to the current collection foil2and the adhesion of the current collection foil2and the active material layer3is also performed suitably. More specifically, the surface of the current collector foil2in the present embodiment is coated with a carbon layer. In this case, if the viscosity of the adhesive5is too low, there is a possibility that the adhesive5will excessively soak into the carbon layer and the current collection foil2and the active material layer3will not be sufficiently adhered. Conversely, when the viscosity of the adhesive5is too high, there is a possibility that the adhesive5will be unlikely to permeate the carbon layer and the thickness of the adhesive5will not be sufficiently reduced. Accordingly, in the present embodiment, by setting the viscosity of the adhesive5when provided to the current collection foil2to 500 mPa·s to 1500 mPa·s, a case is suppressed in which the adhesive force decreases due to excessive permeation of the adhesive5, while the thickness of the adhesive is set to a favorable thickness.

Manufacturing Method

An all-solid-state battery manufacturing method of the present embodiment will be described with reference toFIG.2. The manufacturing method illustrated inFIG.2is performed using the above-described manufacturing apparatus1(seeFIG.1). It should be noted that in the actual manufacturing method, multiple current collection foils2and multiple active material layers3are sequentially stacked. However, in order to simplify the description, in the flowchart shown inFIG.2, a step of stacking (adhering) a current collection foil2and an active material layer3of one set is shown. The all-solid-state battery manufacturing method of the present disclosure includes a current collection foil attachment step (S1), an adhesive provision step and thickness adjustment step (S2), a curing light emission step (S3), and a pressing step (S4).

In the current collection foil attachment step (S1), the current collection foil2is attached to the foil attachment surface21of the press roller20. As described above, in the present embodiment, a current collection foil2with an elongated shape is cut to a predetermined length by the supply/cutting apparatus30and is attached (supplied) to the foil attachment surface21.

In the adhesive provision step, the adhesive5is provided on the current collection foil2attached to the foil attachment surface21. As described above, in the present embodiment, the adhesive5is provided on the current collection foil2by the adhesive provision apparatus50.

In the thickness adjustment step, the thickness of the adhesive5on the current collection foil2is adjusted due to the adhesive contact surface52of the adhesive roller51coming into contact with the adhesive5on the current collection foil2. As a result, the thickness of the adhesive5between the current collection foil2and the active material layer3after the later-described pressing step (S4) is more likely to reach a suitable thickness or less. Accordingly, the shape of the battery unit of the all-solid-state battery is less likely to be disturbed.

In the present embodiment, the adhesive provision step and the thickness adjustment step are performed at the same time (S2). Specifically, the provision of the adhesive5and the adjustment of the thickness of the adhesive are performed at the same time due to the adhesive5supplied to the adhesive contact surface52of the adhesive roller51being transferred onto the current collection foil2. Accordingly, the manufacturing efficiency further improves.

In the curing light emission step (S3), the curing light is emitted to the adhesive5. As a result, the curing reaction of the adhesive5is suitably started, and therefore both the current collection foil2and the active material layer3are adhered by the adhesive5after being pressed.

In the pressing step (S4), the current collection foil2attached to the foil attachment surface21is rotated and moved by the press roller20to the outer surface of the active material layer3transported by the transport apparatus10. Furthermore, the current collection foil2and the active material layer3are pressed in the thickness direction between the press roller20and the transport apparatus10. Accordingly, the current collection foil2and the active material layer3are adhered suitably in a shorter amount of time compared to the case of using a flat plate or the like.

The technique disclosed in the above-described embodiment is merely one example. Accordingly, the technique illustrated in the above-described embodiment can also be changed. For example, a hot melt or the like can also be used as the adhesive instead of the photocurable adhesive. It is also possible to employ only a portion of the multiple techniques illustrated in the above-described embodiment. For example, only one of the technique of adjusting the thickness of the adhesive5using the adhesive roller51and the technique of setting the viscosity of the adhesive5to a suitable viscosity and providing the adhesive5to the current collection foil2may be employed.