Pressing device and pressing method

Abstract

The present invention provides a press apparatus and a press method capable of accurately transferring a solid electrolyte layer to a positive electrode layer. [Solution] A press device 100 for transferring a first solid electrolyte layer SE1 to a positive electrode side sheet member 200, comprising: a transfer sheet roll body 122 around which a transfer sheet 121 having the first solid electrolyte layer SE1 is wound; a first positive electrode side transfer roller 120 for transferring the first solid electrolyte layer SE1 to the positive electrode side sheet member 200; and an expander roll 110 for applying tension to the transfer sheet 121, wherein the expander roll 110 is positioned upstream of the first positive electrode side transfer roller 120 in the transport direction of the positive electrode side sheet member 200 and applies tension to the transfer sheet 121 in the width direction.

Description

Technical Field

[0001] The present invention relates to a pressing device for manufacturing a solid-state battery and a pressing method.

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development on secondary batteries that contribute to energy efficiency have been conducted. [[ID=1…]]

[0003] Conventionally, as a method for manufacturing a solid-state battery, a method of manufacturing by pressing a positive electrode layer, a solid electrolyte layer, and a negative electrode layer with a roll is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the method for manufacturing a solid-state battery described in Patent Document 1, the solid electrolyte layer is transferred to the positive electrode layer by pressing a sheet provided with the solid electrolyte layer onto the positive electrode layer, but there is a risk that the accuracy of the transfer of the solid electrolyte layer may decrease.

[0006] The present invention provides a pressing device and a pressing method capable of accurately transferring a solid electrolyte layer to a positive electrode layer. And, by extension, it contributes to energy efficiency.

Means for Solving the Problems

[0007] One aspect of the present invention is a pressing device for transferring a transfer body to a base material sheet, A transfer sheet roll body formed by winding a transfer sheet having the transfer material, A transfer roller for transferring the transfer body onto the base material sheet, The transfer sheet is provided with an expander roll for applying tension to the transfer sheet, The aforementioned expander roll is In the conveying direction of the base material sheet, it is positioned upstream of the transfer roller and applies tension to the transfer sheet in the width direction.

[0008] Furthermore, other embodiments of the present invention include: A pressing method for transferring a transfer body onto a base sheet, A tension application step in which tension is applied to the transfer sheet unwound from the transfer sheet roll in the width direction perpendicular to the transport direction, A transfer step of transferring the transfer body, which is under tension, to the base material sheet, The process includes a pressing step in which the base material sheet onto which the transfer sheet has been transferred is pressed at a higher pressure than that of the transfer step. [Effects of the Invention]

[0009] According to the present invention, it becomes possible to accurately transfer a solid electrolyte layer to a positive electrode layer. This, in turn, can contribute to improving energy efficiency. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view showing an example of a solid-state battery 1. [Figure 2] Figure 2 shows an example of a press apparatus 100 for manufacturing a solid-state battery 1 in an embodiment. [Figure 3] Figure 3 is a diagram showing a part of the press apparatus 100, and in particular, it is a diagram illustrating an example of the transfer of the first solid electrolyte layer SE1. [Figure 4] Figure 4 is a schematic diagram illustrating an example of an expander roll 110. [Figure 5]FIG. 5 is a diagram showing a part of the pressing device 100, and particularly shows an example of transfer of the intermediate layer transfer roller 150 and the negative electrode side transfer roller 160. [Figure 6] FIG. 6 is a flowchart showing an example of a pressing method using the pressing device 100. [Figure 7] FIG. 7 is a schematic diagram for explaining another example of the expander roll 110. [Figure 8] FIG. 8 is a schematic diagram for explaining still another example of the expander roll 110.

Embodiment for Carrying out the Invention

[0011] Hereinafter, an embodiment will be described with reference to the drawings. The pressing device 100 in the embodiment is used for manufacturing the solid-state battery 1. First, the configuration of the solid-state battery 1 will be described.

[0012] [Solid-State Battery] FIG. 1 is a schematic diagram showing an example of the solid-state battery 1. The solid-state battery 1 is an all-solid-state battery having an electrode 10 in which a negative electrode layer 2, a solid electrolyte layer 3, and a positive electrode layer 4 are laminated. In the embodiment, as shown in FIG. 1, the structure in which the negative electrode layer 2, the solid electrolyte layer 3, the positive electrode layer 4, the solid electrolyte layer 3, and the negative electrode layer 2 are laminated in this order will be described as the laminated structure of the solid-state battery 1. Note that the structure of the solid-state battery 1 is not limited to the above. The solid-state battery 1 may have a configuration that can be used for a solid-state battery such as an exterior body in addition to the electrode 10 shown in FIG. 1.

[0013] The solid electrolyte layer 3 in the solid-state battery 1 has at least a first solid electrolyte layer SE1 disposed on the positive electrode layer 4 side and a negative electrode side solid electrolyte layer SE3 disposed on the negative electrode layer 2 side. The solid electrolyte layer 3 may have a second solid electrolyte layer SE2 disposed adjacent to the first solid electrolyte layer SE1. In the embodiment, the solid electrolyte layer 3 will be described as being composed of the above three layers. An intermediate layer 5 may be optionally disposed between the negative electrode layer 2 and the solid electrolyte layer 3.

[0014] The solid-state battery 1 is not particularly limited, and may be a lithium-ion solid-state secondary battery or a lithium metal secondary battery.

[0015] (Negative electrode layer) The negative electrode layer 2 includes a negative electrode active material layer 21 and a negative electrode current collector layer 22. The negative electrode active material layer 21 is not particularly limited and can be composed of a material that can be used as the negative electrode active material of the solid-state battery 1. Examples of the negative electrode active material constituting the negative electrode active material layer 21 include lithium metal, lithium alloy, silicon-based active materials such as Si and Si alloy, lithium transition metal oxides such as lithium titanate (Li4Ti5O

[0018] , , , , ,

[0017] , ) and the like, transition metal oxides such as TiO2, Nb2O3 and WO3, metal sulfides, metal nitrides, carbon materials such as graphite, soft carbon and hard carbon, and metal indium and the like.

[0016] The negative electrode active material layer 21 may contain materials other than those described above that can be contained in the negative electrode active material layer 21 of the solid-state battery 1. Examples of the above materials include, for example, solid electrolytes, conductive aids, binders, and the like. Examples of the solid electrolyte include the same ones as those contained in the solid electrolyte layer 3 described later. Examples of the conductive aid include carbon black, natural graphite, carbon fiber, carbon nanotube, and the like. Examples of the binder include nitrile-based polymers, polyester-based polymers, acrylic acid-based polymers, cellulose-based polymers, styrene-based polymers, styrene-butadiene-based polymers, vinyl acetate-based polymers, urethane-based polymers, fluoroethylene-based polymers, and the like.

[0017] The negative electrode current collector layer 22 is not particularly limited and can be composed of copper, nickel, stainless steel, or the like. Examples of the shape of the negative electrode current collector layer 22 include, for example, foil shape, plate shape, mesh shape, non-woven fabric shape, foamed shape, and the like. In an embodiment, the negative electrode current collector layer 22 is composed of a negative electrode current collector foil 22a.

[0018] (Solid electrolyte layer) The solid electrolyte layer 3 is formed between the negative electrode layer 2 and the positive electrode layer 4. In this embodiment, the solid electrolyte layer 3 has a structure in which a first solid electrolyte layer SE1, which is placed in contact with the positive electrode layer, a second solid electrolyte layer SE2, and a negative electrode side solid electrolyte layer SE3, which is placed on the negative electrode side, are stacked in this order.

[0019] The first solid electrolyte layer SE1 is positioned in contact with the positive electrode active material layer 41 in the positive electrode layer 4. The solid electrolyte constituting the first solid electrolyte layer SE1 is not particularly limited and can be any material that can be used as an electrolyte in a solid-state battery. Examples include inorganic solid electrolytes such as sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, and lithium-containing salts, as well as polymer-based solid electrolytes such as polyethylene oxide. One type of the above solid electrolyte may be used, or two or more types may be used in combination.

[0020] Furthermore, the first solid electrolyte layer SE1 contains a binder in addition to the solid electrolyte material. The binder can be the same material as the binder that can be contained in the negative electrode active material layer 21. The binder content in the first solid electrolyte layer SE1 relative to the total mass of the first solid electrolyte layer SE1 is equal to or greater than the binder content in the second solid electrolyte layer SE2 relative to the total mass of the second solid electrolyte layer SE2. The upper limit of the binder content in the first solid electrolyte layer SE1 is, for example, 25% by mass. Preferably, the binder content in the first solid electrolyte layer SE1 is 10 to 30% by mass. This makes it easier for the first solid electrolyte layer SE1 to stretch in accordance with the positive electrode layer 4 when the positive electrode layer 4 is pressed.

[0021] In addition to the solid electrolyte material and binder, the first solid electrolyte layer SE1 may also contain materials that can be used in the solid electrolyte layer of a solid-state battery.

[0022] Furthermore, the thickness of the first solid electrolyte layer SE1 (length in the stacking direction of each layer) is preferably thinner than the thickness of the second solid electrolyte layer SE2. The thickness of the first solid electrolyte layer SE1 is preferably, for example, 3 to 15 μm.

[0023] The second solid electrolyte layer SE2 is an arbitrarily placed layer and is positioned adjacent to the first solid electrolyte layer SE1. The solid electrolyte material constituting the second solid electrolyte layer SE2 is not particularly limited and can be the same as the solid electrolyte material constituting the first solid electrolyte layer SE1. The second solid electrolyte layer SE2 may contain a binder or the like in addition to the solid electrolyte material, similar to the first solid electrolyte layer SE1. The binder content of the second solid electrolyte layer SE2 is less than or equal to the binder content of the first solid electrolyte layer SE1. The binder content of the second solid electrolyte layer SE2 is preferably, for example, 10 to 30 mass%. This can improve the energy density of the solid battery 1. The second solid electrolyte layer SE2 may contain a support. The support may be a three-dimensional structure such as a mesh, woven fabric, nonwoven fabric, embossed body, punched body, expanded, or foam. The second solid electrolyte layer SE2 does not need to contain the support.

[0024] The thickness of the second solid electrolyte layer SE2 (length in the stacking direction of each layer) is preferably greater than the thickness of the first solid electrolyte layer SE1. Furthermore, the thickness of the second solid electrolyte layer SE2 is preferably greater than the thickness of the negative electrode side solid electrolyte layer SE3, which will be described later. The thickness of the second solid electrolyte layer SE2 is preferably, for example, 10 to 50 μm.

[0025] The negative electrode solid electrolyte layer SE3 is located on the negative electrode layer side. The negative electrode solid electrolyte layer SE3 is located adjacent to the negative electrode layer 2. If the solid battery 1 has an intermediate layer 5 as shown in Figure 1, the negative electrode solid electrolyte layer SE3 may be located adjacent to the intermediate layer 5.

[0026] The solid electrolyte material constituting the negative electrode solid electrolyte layer SE3 is not particularly limited and can be the same as the solid electrolyte material constituting the first solid electrolyte layer SE1. The binder content of the negative electrode solid electrolyte layer SE3 is preferably, for example, 1.3 to 8.7 mass%. In terms of volume%, the binder content of the negative electrode solid electrolyte layer SE3 is preferably, for example, 2.7 volume% to 10 volume%. The binder content of the negative electrode solid electrolyte layer SE3 is less than the binder content of the first solid electrolyte layer SE1.

[0027] The thickness of the negative electrode solid electrolyte layer SE3 (length in the stacking direction of each layer) is preferably thinner than the thickness of the second solid electrolyte layer SE2. The thickness of the negative electrode solid electrolyte layer SE3 is preferably, for example, 3 to 8.5 μm.

[0028] (Positive electrode layer) The positive electrode layer 4 comprises a positive electrode active material layer 41 and a positive electrode current collector layer 42. In one embodiment, the positive electrode layer 4 has a configuration in which two positive electrode active material layers 41 are laminated on both sides of one positive electrode current collector layer 42. However, the configuration of the positive electrode layer 4 is not limited to the above, and it may have a configuration in which one positive electrode active material layer 41 is laminated on one side of one positive electrode current collector layer 42.

[0029] The positive electrode active material layer 41 is not particularly limited and can be composed of a material that can be used as a positive electrode active material in a solid-state battery. Examples of positive electrode active materials that make up the positive electrode active material layer 41 include LiCoO2, LiNiO2, and LiCo x Ni y Mn z Layered cathode active material particles such as O2(x+y+z=1), LiVO2, LiCrO2, LiMn2O4, Li(Ni 0.25 Mn 0.75Examples of positive electrode active materials include spinel-type positive electrode active materials such as 2O4, LiCoMnO4, and Li2NiMn3O8; olivine-type positive electrode active materials such as LiCoPO4, LiMnPO4, and LiFePO4; conductive polymers such as solid solution oxides (Li2MnO3-LiMO2 (M=Co, Ni, etc.)), polyaniline, and polypyrrole; sulfides such as Li2S, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, and Li-Mo-S compounds; and mixtures of sulfur and carbon. The positive electrode active material may consist of one of the above materials or a composition of two or more of the above materials.

[0030] The positive electrode active material layer 41 may contain a binder or the like. The binder content of the positive electrode active material layer 41 is preferably 0.5 to 5% by mass. Preferably, it may be 2.56% by mass. The thickness of the positive electrode active material layer 41 (length in the stacking direction of each layer) is preferably, for example, 80 to 100 μm. This improves the battery capacity of the solid-state battery 1.

[0031] The positive electrode current collector layer 42 is not particularly limited, but can be made of, for example, aluminum, stainless steel, conductive carbon (e.g., graphite, carbon nanotubes, etc.). The shape of the positive electrode current collector layer 42 can be, for example, foil, plate, mesh, nonwoven fabric, or foam. In this embodiment, the positive electrode current collector layer 42 is made of a positive electrode current collector foil 42a.

[0032] (Middle class) The intermediate layer 5 is positioned between the negative electrode layer 2 and the solid electrolyte layer 3. The intermediate layer 5 has the function of uniformly depositing lithium metal, for example, when the solid battery 1 is a lithium metal battery. Therefore, the interface between the intermediate layer 5 and the solid electrolyte layer 3 is stabilized. When the solid battery 1 is a lithium metal secondary battery having the intermediate layer 5, the solid battery 1 may be an anode-free battery in which the negative electrode active material layer 21 does not exist at the time of the first charge. In this case, the lithium metal layer as the negative electrode active material layer 21 is formed after the first charge and discharge.

[0033] The materials constituting the intermediate layer 5 are not particularly limited, but examples include metals that can be alloyed with lithium, and amorphous carbon. Examples of metals that can be alloyed with lithium include tin (Sn), silicon (Si), zinc (Zn), magnesium (Mg), gold (Au), platinum (Pt), palladium (Pd), silver (Ag), aluminum (Al), bismuth (Bi), and antimony (Sb). The metals that can be alloyed with lithium may also be nanoparticles. Examples of amorphous carbon include carbon blacks such as acetylene black, furnace black, and Ketjen black, as well as coke and activated carbon. The amorphous carbon may be easily graphitizable carbon (soft carbon), difficult-to-graphitize carbon (hard carbon), CNTs (carbon nanotubes), fullerenes, and graphene. The intermediate layer may also contain a binder in addition to the above materials.

[0034] [Pressing device] Next, the configuration of the press apparatus 100 for manufacturing the solid battery 1 configured as described above will be explained. Figure 2 shows an example of the press apparatus 100 in the embodiment. The press apparatus 100 has as its main components an expander roll 110, a first positive electrode side transfer roller 120, a peeling roller 130 (see Figure 3), a second positive electrode side transfer roller 140, an intermediate layer transfer roller 150 (see Figure 5), a negative electrode side transfer roller 160 (see Figure 5), a negative electrode side sheet member lamination roller 170, a positive electrode press roll 180, and an integrating press roll 190. The press apparatus 100 continuously manufactures the solid battery 1 while feeding the positive electrode side sheet member 200 in one direction using these rollers. Figure 1 shows the range that is pressed or transferred in the positive electrode press step S3, the second solid electrolyte layer transfer step S4, the intermediate layer transfer step S5, the negative electrode side solid electrolyte layer transfer step S6, and the integrating press step S8, which will be described later.

[0035] The positive electrode side sheet member 200 is an example of a "base sheet," and is a sheet-like member obtained by laminating a positive electrode active material layer 41 on a positive electrode current collector foil 42a that constitutes the positive electrode current collector layer 42. The positive electrode side sheet member 200 is fed out by a roller (not shown) and transported so as to extend continuously from the base end to the end in the manufacturing line of the solid-state battery 1.

[0036] The expander roll 110, the first positive electrode side transfer roller 120, the peeling roller 130, the second positive electrode side transfer roller 140, the intermediate layer transfer roller 150, the negative electrode side transfer roller 160, and the negative electrode side sheet member lamination roller 170 are each composed of a pair of rotating bodies.

[0037] These rotating bodies are arranged in the following order from upstream to downstream along the transport direction (hereinafter simply referred to as the "transport direction"), which is the direction in which the positive electrode side sheet member 200 is transported: expander roll 110, first positive electrode side transfer roller 120, peeling roller 130, positive electrode press roll 180, second positive electrode side transfer roller 140, negative electrode side sheet member lamination roller 170, and integrating press roll 190.

[0038] The intermediate layer transfer roller 150 and the negative electrode side transfer roller 160 are positioned away from the transport line (hereinafter simply referred to as the "transport line") on which the positive electrode side sheet member 200 is transported in the transport direction, and perform transfer pressing of the intermediate layer 5 or the negative electrode side solid electrolyte layer SE3. Subsequently, as will be described later, the intermediate layer 5 and the negative electrode layer 2 on which the negative electrode side solid electrolyte layer SE3 has been transferred are transported to the upper or lower side of the positive electrode side sheet member 200, join the transport line of the positive electrode side sheet member 200, and are laminated by the negative electrode side sheet member lamination roller 170.

[0039] The first positive electrode side transfer roller 120, the second positive electrode side transfer roller 140, the intermediate layer transfer roller 150, and the negative electrode side transfer roller 160 perform a transfer press by passing a sheet of the substrate to be transferred and a sheet on which the solid electrolyte layer to be transferred is provided between a pair of rollers while applying pressure.

[0040] Specifically, the first positive electrode side transfer roller 120 transfers the first solid electrolyte layer SE1 to the positive electrode side sheet member 200 by sandwiching a transfer sheet 121, which is a sheet on which the first solid electrolyte layer SE1 is provided, between a pair of rollers and applying pressure. The first solid electrolyte layer SE1 is an example of a "transfer body".

[0041] Furthermore, in this embodiment, as described above, an expander roll 110 is positioned upstream of the first positive electrode side transfer roller 120. The expander roll 110 is configured to apply tension to the transfer sheet 121 in the width direction (hereinafter simply referred to as "width direction") perpendicular to the transport direction of the positive electrode side sheet member 200, before the first solid electrolyte layer SE1 is transferred to the positive electrode side sheet member 200 by the first positive electrode side transfer roller 120.

[0042] Here, we will explain why the expander roll 110 is provided in this embodiment. For example, as is conventionally known, when the first solid electrolyte layer SE1 is transferred to the positive electrode sheet member 200 by the first positive electrode side transfer roller 120 without the expander roll 110, the transfer may not be performed properly. In particular, because no tension is applied in the width direction, the accuracy of the transfer of the first solid electrolyte layer SE1 may decrease. Furthermore, if the accuracy of the transfer decreases in this way, the accuracy of the bonding between the first solid electrolyte layer SE1 and the positive electrode layer 4 (positive electrode active material layer 41) may also decrease. Therefore, in this embodiment, the expander roll 110 is provided to improve the accuracy of the transfer of the first solid electrolyte layer SE1.

[0043] Figure 3 shows a more detailed enlarged view of the area enclosed by the dashed line in Figure 2. As shown here, the expander roll 110 applies tension in the width direction in addition to the transport direction to the transfer sheet 121 as it is unwound from the transfer sheet roll body 122 around which the transfer sheet 121 is wound. The arrows shown for each roller and roll body in Figure 3 indicate the rotation direction of each roller and roll body.

[0044] Specifically, as shown in Figure 4, the expander roll 110 is a roll body that extends in the width direction, with a larger diameter at the central end than at both ends. In other words, the expander roll 110 has a so-called crown shape, where the outer diameter gradually decreases from the central end to the end end. The crown shape may be a tapered shape where the cross-section is straight from the central end to the end end, or it may be a curved shape where it is curved from the central end to the end end.

[0045] Due to this shape, the transfer sheet 121 is pulled towards both ends, that is, tension is applied in the width direction. Regarding tension in the transport direction, it can be assumed that some tension is applied even if the expander roll 110 is not provided, but it is expected that the tension in the transport direction will increase with the provision of the expander roll 110.

[0046] As shown in Figures 3 and 4, the transfer sheet 121 comprises a first solid electrolyte layer SE1 and a base sheet 123 on which the first solid electrolyte layer SE1 is provided. The base sheet 123 is peeled off from the transferred first solid electrolyte layer SE1 by a peeling roller 130, which will be described later, and is made of, for example, PET (polyethylene terephthalate). In Figure 3, the first solid electrolyte layer SE1 of the transfer sheet 121 unwound from the transfer sheet roll 122 is shown by a solid line, and the base sheet 123 that is peeled off is shown by a dashed line.

[0047] Furthermore, the expander roll 110 in this embodiment has a positioning section 111 for positioning the transfer sheet 121. In the example shown in Figure 4, an example of the positioning section 111 is shown in which a guide groove 111a is formed to guide the transfer sheet 121. By guiding the transfer sheet 121 with this guide groove 111a, the movement of the transfer sheet 121 in the width direction can be restricted. Note that the configuration of the positioning section 111 may be other as long as the transfer sheet 121 can be positioned in the width direction. For example, instead of the guide groove 111a, a pair of barrier sections may be formed in the width direction.

[0048] The transfer sheet 121, conveyed via the expander roll 110, is then transferred to the positive electrode side sheet member 200 by the first positive electrode side transfer roller 120. To perform this transfer accurately, it is preferable that the transfer sheet 121 and the positive electrode side sheet member 200 are parallel during the transfer press by the first positive electrode side transfer roller 120. In this embodiment, as described above, a positioning section 111 for positioning the transfer sheet 121 is formed on the expander roll 110, so that tension is applied to the transfer sheet 121 in the width direction (and conveying direction), making it possible to achieve the desired parallel state between the transfer sheet 121 and the positive electrode side sheet member 200.

[0049] As a prerequisite, the expander roll 110 is equipped with a motor (not shown) capable of adjusting the unwinding speed of the transfer sheet 121. By controlling the rotational speed of this motor, the relative speed between the positive electrode side sheet member 200 and the transfer sheet 121, which are moving in the transport direction at a predetermined speed, can be adjusted.

[0050] Thus, the expander roll 110 has the function of applying tension to the transfer sheet 121 in the width direction, as well as the function of making the transfer sheet 121 parallel to the positive electrode side sheet member 200. In other words, it can be said that the expander roll 110 also has the function of adjusting the angle at which the transfer sheet 121 enters the positive electrode side sheet member 200 in order to achieve that parallel state.

[0051] A peeling roller 130 is positioned downstream of the first positive electrode side transfer roller 120. The peeling roller 130 peels the base sheet 123 from the transfer sheet 121 on which the first solid electrolyte layer SE1 is provided. Specifically, as shown in Figure 3, it peels the base sheet 123 from the first solid electrolyte layer SE1 that has been transferred and pressed. At this time, the peeling roller 130 also functions as a restraint when peeling the base sheet 123 from the first solid electrolyte layer SE1. The peeled base sheet 123 is then wound up by a base roll body 131 that winds up the base sheet 123.

[0052] In this manner, the transfer sheet 121 unwound from the transfer sheet roll 122 is subjected to tension mainly in the width direction by the expander roll 110, and in this state, the first solid electrolyte layer SE1 is transferred to the positive electrode side sheet member 200 by the first positive electrode side transfer roller 120. Then, the base sheet 123 is wound up from the transferred first solid electrolyte layer SE1 by the base sheet roll 131 via the release roller 130.

[0053] As shown in Figure 3, the transfer sheet 121 is provided on both sides of the positive electrode sheet member 200 so as to be vertically symmetrical, and is configured to transfer the first solid electrolyte layer SE1 to both sides of the positive electrode sheet member 200. This allows the first solid electrolyte layer SE1 to be transferred to both sides of the positive electrode sheet member 200 simultaneously.

[0054] As shown in Figure 2, the second positive electrode side transfer roller 140 transfers the second solid electrolyte layer SE2 onto the positive electrode side sheet member 200, which has been pressed with the first solid electrolyte layer SE1 transferred onto it.

[0055] As shown in Figure 5, the intermediate layer transfer roller 150 transfers the intermediate layer 5 onto the negative electrode active material layer 21, which is laminated on the negative electrode current collector foil 22a. As a result, the intermediate layer 5 is positioned between the negative electrode active material layer 21 and the negative electrode side solid electrolyte layer SE3.

[0056] As shown in Figure 5, the negative electrode side transfer roller 160 transfers the negative electrode side solid electrolyte layer SE3 onto the intermediate layer 5 to form the negative electrode side sheet member 210.

[0057] As shown in Figure 2, the negative electrode side sheet member lamination roller 170 transports and laminates the negative electrode side sheet member 210, on which the negative electrode side solid electrolyte layer SE3 has been transferred, onto the positive electrode side sheet member 200, on which the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 have been transferred.

[0058] As shown in Figure 2, the positive electrode press roll 180 and the integrated press roll 190, like each transfer roller, are each composed of a pair of rotating rollers. The positive electrode side sheet member 200, on which solid electrolyte layers and the like are laminated according to each process, is passed through the pair of rollers under pressure to increase its density. The positive electrode press roll 180 is an example of a "press roll" and presses the positive electrode side sheet member 200 on which the first solid electrolyte layer SE1 has been transferred. The integrated press roll 190 presses the electrodes 10 together with the positive electrode side sheet member 200 and the negative electrode side sheet member 210 laminated together. As a result, the positive electrode side sheet member 200 and the negative electrode side sheet member 210 are integrated, and at the same time, the first solid electrolyte layer SE1, the second solid electrolyte layer SE2, and the negative electrode side solid electrolyte layer SE3 are increased in density.

[0059] [Pressing method] Next, a pressing method using the pressing device 100 configured as described above for the solid-state battery 1 will be explained. Figure 6 is a flowchart showing an example of the pressing method. The pressing method includes, as a process, a positive electrode side sheet member feeding step S1, a first solid electrolyte layer transfer step S2, a positive electrode pressing step S3, a second solid electrolyte layer transfer step S4, an intermediate layer transfer step S5, a negative electrode side solid electrolyte layer transfer step S6, a negative electrode side sheet member lamination step S7, and an integrated pressing step S8. The first solid electrolyte layer transfer step S2 also includes a tensioning step S20 and a transfer step S21.

[0060] The positive electrode side sheet member feeding step S1 is a step in which the positive electrode side sheet member 200 is conveyed and fed out by a conveying roller (not shown). That is, the positive electrode side sheet member 200, which is laminated by coating the positive electrode active material onto the positive electrode current collector foil 42a that constitutes the positive electrode current collector layer 42, is fed out.

[0061] The first solid electrolyte layer transfer step S2 is a step in which the first solid electrolyte layer SE1 is transferred to the positive electrode side sheet member 200 by the first positive electrode side transfer roller 120. Specifically, the first solid electrolyte layer transfer step S2 performs the tension application step S20 and the transfer step S21.

[0062] The tension-applying step S20 is a step in which tension is applied in the width direction to the transfer sheet 121 unwound from the transfer sheet roll body 122 by the expander roll 110 described above. That is, since the diameter of the central part of the expander roll 110 is larger than the diameter of both ends, tension is applied in the width direction as the transfer sheet 121 is pulled toward both ends of the expander roll 110. Furthermore, as described above, the transfer sheet 121 is positioned in the width direction by the guide groove 111a formed in the expander roll 110, so that tension is applied in the width direction and the transfer sheet 121 and the positive electrode side sheet member 200 become parallel, and the transfer step S21 described later can be performed while maintaining this parallel state.

[0063] The transfer step S21 is a step in which the first solid electrolyte layer SE1 on the tensioned transfer sheet 121 is transferred to the positive electrode side sheet member 200. Specifically, the slurry constituting the first solid electrolyte layer SE1 is passed over the positive electrode side sheet member 200 under pressure by a pair of first positive electrode side transfer rollers 120 to perform a transfer press. The pressure at this time is, for example, 50 to 500 MPa at room temperature (for example, 10 to 35°C). Preferably, it is 100 MPa at 25°C.

[0064] After the transfer step, the base sheet 123 is peeled off from the first solid electrolyte layer SE1 that has been transferred and pressed by the peeling roller 130. The peeled base sheet 123 is then wound up by the base roll body 131 that winds up the base sheet 123.

[0065] The positive electrode pressing step S3 is a step in which the positive electrode side sheet member 200, onto which the first solid electrolyte layer SE1 has been transferred, is pressed by the positive electrode pressing roll 180. This positive electrode pressing step S3 increases the density of the positive electrode. The pressing pressure for increasing density is, for example, about 800 to 1200 MPa at 25 to 100°C. The laminate of the densified positive electrode side sheet member 200 and the first solid electrolyte layer SE1 is conveyed downstream on the conveyor line.

[0066] The second solid electrolyte layer transfer step S4 is a step in which, after the positive electrode press step S3, the second solid electrolyte layer SE2 is transferred onto the positive electrode side sheet member 200, which has been pressed with the first solid electrolyte layer SE1 transferred to it, by the second positive electrode side transfer roller 140. Specifically, the second solid electrolyte layer transfer step S4 positions the second solid electrolyte layer SE2 on the positive electrode side sheet member 200, to which the first solid electrolyte layer SE1 has been transferred, within a range guided by a guide roller (not shown). Then, the slurry constituting the second solid electrolyte layer SE2 is passed over the positive electrode side sheet member 200 under pressure by the second positive electrode side transfer roller 140, which acts as a transfer roller, and a transfer press is performed. The pressure at this time is, for example, 50 to 500 MPa at room temperature (e.g., 10 to 35°C). In this way, the positive electrode side sheet member 200 is pressed two or more times. Preferably, it is 150 MPa at 25°C.

[0067] Meanwhile, the negative electrode side sheet member 210 is prepared at a location separate from the transport line. First, as shown in the upper part of Figure 5, the intermediate layer 5 is transferred to the negative electrode active material layer 21 laminated on the negative electrode current collector foil 22a by the intermediate layer transfer roller 150 (intermediate layer transfer step S5). Then, as shown in the lower part of Figure 5, the negative electrode side solid electrolyte layer SE3 is transferred onto the intermediate layer 5 by the negative electrode side transfer roller 160 to form the negative electrode side sheet member 210 (negative electrode side solid electrolyte layer transfer step S6). As a result, the intermediate layer 5 is positioned between the negative electrode active material layer 21 and the negative electrode side solid electrolyte layer SE3. In this embodiment, the negative electrode side sheet member 210 includes a laminated negative electrode current collector foil 22a, negative electrode active material layer 21, intermediate layer 5, and negative electrode side solid electrolyte layer SE3, but the negative electrode active material layer 21 and intermediate layer 5 may be omitted.

[0068] In the intermediate layer transfer step S5, the slurry constituting the intermediate layer 5 is positioned on the negative electrode active material layer 21 within a range guided by a guide roller (not shown). Then, the intermediate layer 5 is passed over the negative electrode active material layer 21 under pressure by an intermediate layer transfer roller 150, which acts as a transfer roller, to perform an intermediate layer transfer press to transfer the intermediate layer 5 to the negative electrode active material layer 21. The pressure at this time is, for example, 50 to 800 MPa at room temperature (for example, 10 to 35°C). More preferably, it is in the range of 300 MPa or more and 800 MPa or less at 25°C.

[0069] In the negative electrode solid electrolyte layer transfer step S6, the slurry constituting the negative electrode solid electrolyte layer SE3 is positioned on the intermediate layer 5 within a range guided by a guide roller (not shown). Then, the negative electrode solid electrolyte layer SE3 is passed over the intermediate layer 5 under pressure by the negative electrode transfer roller 160, which acts as a transfer roller, and the negative electrode active material layer transfer press is performed to transfer the negative electrode solid electrolyte layer SE3 to the intermediate layer 5. The pressure at this time is, for example, 600 to 800 MPa at room temperature (for example, 10 to 35°C).

[0070] Regarding pressure, the pressing pressure in the positive electrode pressing step S3 is not only the maximum pressure applied to the positive electrode side sheet member 200, but also the maximum pressing pressure in the entire pressing apparatus method. The positive electrode side sheet member 200 is pressed at high pressure to increase its energy density and densify the electrodes. The maximum pressing pressure in the positive electrode pressing step S3 is greater than or equal to the maximum pressing pressure applied to the negative electrode side sheet member 210.

[0071] Furthermore, the pressure during the transfer of the first solid electrolyte layer in step S2 and the second solid electrolyte layer in step S4 is less than the pressure during the pressing of the positive electrode in step S3. Also, the pressure during the transfer of the first solid electrolyte layer in step S2 and the second solid electrolyte layer in step S4 is less than the pressure during the pressing of the negative electrode solid electrolyte layer in step S6.

[0072] Since the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 contain a relatively large amount of binder, the press pressure during transfer can be reduced. Furthermore, by setting the transfer press pressure as low as possible, the amount of stretching of the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 due to the transfer press can be reduced. Therefore, in the subsequent integration press step S8, etc., room is left for the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 to stretch, and the first solid electrolyte layer SE1 can be stretched to follow the positive electrode layer 4. This improves the bonding of the first solid electrolyte layer SE1 with the positive electrode active material layer 41.

[0073] After the negative electrode solid electrolyte layer transfer step S6, the formed negative electrode sheet member 210 is cut with a cutter while being supported by the feed roll that feeds out the material to be transferred in the negative electrode solid electrolyte layer transfer step S6. The negative electrode sheet member 210 is cut to the design dimensions of the negative electrode layer 2 of the solid battery 1.

[0074] The negative electrode side sheet member 210, cut to the design dimensions, is transported to the positive electrode side sheet member 200 so as to merge with the transport line of the positive electrode side sheet member 200, as shown in Figures 2 and 6, and is stacked on the positive electrode side sheet member 200. At this time, prior to the integration press step S8 described later, a first solid electrolyte layer SE1 is provided on the lower side of the positive electrode side sheet member 200, and a second solid electrolyte layer SE2 is provided on top of it, on the surface of the positive electrode side sheet member 200 facing the negative electrode side solid electrolyte layer SE3. Then, in its cut state, the negative electrode side sheet member 210 is placed on the positive electrode side sheet member 200.

[0075] Specifically, in the negative electrode side sheet member lamination step S7, the negative electrode side sheet member 210, on which the negative electrode side solid electrolyte layer SE3 has been transferred, is transported and laminated onto the positive electrode side sheet member 200, on which the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 have been transferred, by the negative electrode side sheet member lamination roller 170. In the negative electrode side sheet member lamination step S7, the negative electrode side sheet member 210, cut to the design dimensions, is positioned on the positive electrode side sheet member 200, on which the first solid electrolyte layer SE1 and the second solid electrolyte layer SE2 have been transferred, within a range guided by a guide roller (not shown).

[0076] Thus, with the positive electrode sheet member 200 and the negative electrode sheet member 210 stacked, the electrodes 10 are pressed together by the integrating press roll 190 (integrating press step S8). Immediately before the integrating press step S8, the thickness of the positive electrode sheet member 200 is greater than the thickness of the negative electrode sheet member 210 in the stacking direction. The pressure at this time is, for example, about 500 to 900 MPa at 25 to 100°C. The integrating press step S8 integrates the positive electrode sheet member 200 and the negative electrode sheet member 210, and at the same time, the first solid electrolyte layer SE1, the second solid electrolyte layer SE2, and the negative electrode solid electrolyte layer SE3 become denser. Comparing the pressing pressure of the integrating press step S8 and the positive electrode press step S3, the pressing pressure of the positive electrode press step S3 is greater than the pressing pressure of the integrating press step S8.

[0077] After the integration press step S8, the formed electrode 10 is cut with a rotary cutter.

[0078] Furthermore, the following processes—transfer of the first solid electrolyte layer SE1 in the first solid electrolyte layer transfer step S2, pressing of the positive electrode side sheet member 200 in the positive electrode press step S3, transfer of the second solid electrolyte layer SE2 in the second solid electrolyte layer transfer step S4, lamination of the negative electrode side sheet member 210 before integration in the negative electrode side sheet member lamination step S7, and integration pressing in the integration press step S8—are performed on both sides of the positive electrode side sheet member 200 that was fed out in the positive electrode side sheet member feeding step S1. As a result, a solid-state battery 1 is obtained in which each layer is symmetrically laminated on both the upper and lower surfaces, sandwiching the positive electrode side sheet member 200, as shown in Figure 1.

[0079] Thus, in this embodiment, by providing the expander roll 110, widthwise tension can be applied to the transfer sheet 121, allowing the first solid electrolyte layer SE1 to be transferred to the positive electrode side sheet member 200 while widthwise tension is applied. As a result, the accuracy of the transfer of the first solid electrolyte layer SE1 can be improved. In other words, the first solid electrolyte layer SE1 can be transferred to the positive electrode layer 4 with high accuracy, and as a result, the accuracy of the bonding between the first solid electrolyte layer SE1 and the positive electrode layer 4 (positive electrode active material layer 41) can be improved.

[0080] While embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications and alterations can be conceived within the scope of the claims, and these are also understood to naturally fall within the technical scope of the present invention. Furthermore, the components of the above embodiments may be combined in any way without departing from the spirit of the invention.

[0081] For example, in the above-described embodiment, various solid electrolyte layers were laminated on both sides of the positive electrode sheet member 200, but this lamination may be configured to be laminated on only one side.

[0082] Furthermore, the shape of the expander roll 110 may be configured as shown in Figures 7 and 8, in addition to the example shown in Figure 4. For example, as shown in Figure 7, the expander roll 110 may be a straight roll that is bent so that it is convex towards the center of the transfer sheet 121. Alternatively, as shown in Figure 8, the expander roll 110 may be configured such that the diameter at the center is smaller than the diameter at both ends. In other words, the expander roll 110 may have a shape in which the outer diameter gradually decreases from the ends towards the center, contrary to the example shown in Figure 4.

[0083] This specification contains at least the following information. The components indicated in parentheses in the embodiments described above are, but are not limited thereto.

[0084] (1) A press device (press device 100) for transferring a transfer body (first solid electrolyte layer SE1) to a base sheet (positive electrode side sheet member 200), A transfer sheet roll body (transfer sheet roll body 122) is formed by winding a transfer sheet (transfer sheet 121) having the transfer material, A transfer roller (first positive electrode side transfer roller 120) for transferring the transfer body to the base material sheet, The system includes an expander roll (expander roll 110) that applies tension to the transfer sheet, The aforementioned expander roll is In the conveying direction of the base material sheet, a device is positioned upstream of the transfer roller and applies tension to the transfer sheet in the width direction. Pressing device.

[0085] According to (1), since tension in the width direction can be applied to the transfer sheet, the transfer body can be transferred to the base sheet while tension in the width direction is applied, and as a result, the accuracy of the transfer of the transfer body can be improved.

[0086] (2) The press apparatus described in (1), The aforementioned transfer material is a solid electrolyte layer (first solid electrolyte layer SE1), The aforementioned base sheet is the positive electrode side sheet member (positive electrode side sheet member 200). Pressing device.

[0087] According to (2), the accuracy of transferring the first solid electrolyte layer to the positive electrode sheet member can be improved.

[0088] (3) A press apparatus as described in (1) or (2), The expander roll has a diameter at the center that is larger than the diameter at both ends, or the diameter at the center is larger than the diameter at both ends, in a direction perpendicular to the conveying direction of the base material sheet. Pressing device.

[0089] According to (3), the transfer sheet is pulled in a width direction perpendicular to the transport direction because the diameter of the central part is larger than the diameter of the ends, or the diameter of the ends is larger than the diameter of the central part, so that the transfer body provided on the transfer sheet can be transferred while the desired tension is applied.

[0090] (4) A press apparatus as described in (1) or (2), The aforementioned expander roll includes: A positioning section (positioning section 111) for positioning the transfer sheet is formed. Pressing device.

[0091] According to (4), the positioning unit positions the transfer sheet in the width direction, thus preventing misalignment of the transfer sheet in the width direction.

[0092] (5) A press apparatus as described in (1) or (2), The transfer sheet is provided on both sides of the base material sheet, The transfer body is transferred to both sides of the base sheet. Pressing device.

[0093] According to (5), the transfer material can be transferred to both sides of the base sheet simultaneously.

[0094] (6) The press apparatus described in (4), The aforementioned expander roll is The positioning unit is configured to ensure that the transfer sheet and the base material sheet are parallel to each other. Pressing device.

[0095] According to (6), the positioning unit positions the transfer sheet and applies tension to it, so that the transfer sheet can be made parallel to the base sheet, and by performing the transfer in this parallel state, the accuracy of the transfer can be improved compared to, for example, when the transfer is performed in a non-parallel state.

[0096] (7) A press apparatus as described in (1) or (2), The transfer sheet comprises the transfer body and a base sheet (base sheet 123) on which the transfer body is provided. In the conveying direction of the base material sheet, a peeling roller (peeling roller 130) is positioned downstream of the transfer roller to peel the base material sheet from the transfer body transferred to the base material sheet. Pressing device.

[0097] According to (7), after transferring the transfer body to the base material sheet, the base material sheet can be peeled off from the transfer body. Furthermore, because tension is applied to the transfer sheet in the width direction, the base material sheet can be peeled off more easily than, for example, if no tension is applied in the width direction.

[0098] (8) The press apparatus described in (7), The system further comprises a press roll (positive electrode press roll 180) that applies high pressure to the base material sheet onto which the transfer material has been transferred, The press roll is positioned downstream of the peeling roller. Pressing device.

[0099] According to (8), by applying high pressure with a press roll, the density of the transfer material and the base sheet can be increased.

[0100] (9) A pressing method for transferring a transfer body (first solid electrolyte layer SE1) to a base sheet (positive electrode side sheet member 200), A tension application step (tension application step S20) is performed to apply tension to the transfer sheet unwound from the transfer sheet roll (transfer sheet roll 122) in the width direction perpendicular to the transport direction, A transfer step (transfer step S21) is performed to transfer the transfer body, which is under tension, to the base material sheet, The system includes a press step (positive electrode press step S3) in which the base material sheet onto which the transfer sheet has been transferred is pressed at a higher pressure than that of the transfer step. Pressing method.

[0101] According to (9), since tension in the width direction can be applied to the transfer sheet, the transfer body can be transferred to the base sheet while tension in the width direction is applied, and as a result, the accuracy of the transfer of the transfer body can be improved. [Explanation of Symbols]

[0102] 100 Pressing device 110 Expander Roll 120 First positive electrode side transfer roller (transfer roller) 121 Transfer Sheet 122 Transfer Sheet Roll 123 Base sheet 130 peeling roller 180 Positive electrode press roll (press roll) 200 Positive electrode side sheet material (base sheet) SE1 First solid electrolyte layer (transfer material) S3 Positive electrode press step (press step) S21 Transfer Step S20 Tension application step

Claims

1. A press device for transferring a transfer body onto a base material sheet, A transfer sheet roll body formed by winding a transfer sheet having the transfer material, A transfer roller for transferring the transfer body onto the base material sheet, The transfer sheet is provided with an expander roll for applying tension to the transfer sheet, The aforementioned expander roll is In the conveying direction of the base material sheet, a device is positioned upstream of the transfer roller and applies tension to the transfer sheet in the width direction. Pressing device.

2. A press apparatus according to claim 1, The aforementioned transfer material is a solid electrolyte layer, The aforementioned base sheet is the positive electrode side sheet member. Pressing device.

3. A press apparatus according to claim 1 or 2, The expander roll has a diameter at the center that is larger than the diameter at both ends, or the diameter at the center is larger than the diameter at both ends, in a direction perpendicular to the conveying direction of the base material sheet. Pressing device.

4. A press apparatus according to claim 1 or 2, The aforementioned expander roll includes: A positioning section is formed for positioning the transfer sheet. Pressing device.

5. A press apparatus according to claim 1 or 2, The transfer sheet is provided on both sides of the base material sheet, The transfer body is transferred to both sides of the base sheet. Pressing device.

6. A press apparatus according to claim 4, The aforementioned expander roll is The positioning unit is configured to ensure that the transfer sheet and the base material sheet are parallel to each other. Pressing device.

7. A press apparatus according to claim 1 or 2, The transfer sheet comprises the transfer body and a base sheet on which the transfer body is provided. In the conveying direction of the base material sheet, a peeling roller is positioned downstream of the transfer roller to peel the base material sheet from the transfer body transferred to the base material sheet. Pressing device.

8. A press apparatus according to claim 7, The system further comprises a press roll for applying high pressure to the base material sheet onto which the transfer material has been transferred, The press roll is positioned downstream of the peeling roller. Pressing device.

9. A pressing method for transferring a transfer body onto a base sheet, A tension application step in which tension is applied to the transfer sheet unwound from the transfer sheet roll in the width direction perpendicular to the transport direction, A transfer step of transferring the transfer body, which is under tension, to the base material sheet, The system comprises a pressing step in which the base material sheet onto which the transfer sheet has been transferred is pressed at a higher pressure than that of the transfer step, Pressing method.

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