Monocell

Abstract

The present disclosure provides a cell capable of improving energy density per unit area and energy density per unit volume. A single cell in which a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer are laminated in this order, the electrolyte layer and the second electrode active material layer having a peripheral region and an inner region further inward than the peripheral region when viewed from the lamination direction of the layers constituting the single cell, the first electrode active material layer is laminated only on the inner region, the second current collector layer is folded so as to include the electrolyte layer and the second electrode active material layer therein, and the second current collector layer is bonded to the first current collector layer in the peripheral region via an insulating sealing member to form a bonding portion, thereby forming a gap between the first current collector layer and the second current collector layer. The first electrode active material layer, the electrolyte layer, and the second electrode active material layer are sealed by the first current collector layer, the insulating sealing member, and the second current collector layer.

Description

Technical Field

[0001] The present disclosure relates to a thin single battery. Background Art

[0002] In recent years, as portable devices and the like have become thinner, the batteries mounted on these devices are also required to be thinner and smaller. As a thin battery, it is known that a battery is sealed by sandwiching a single cell with two laminate films and heat-melting the ends. This thin battery can suppress the deterioration caused by moisture in the battery by sealing the ends, but since the sealing part is not related to charging and discharging, from the perspective of energy density, the sealing part is required to be as small as possible. In thin and small batteries, the following power storage device is disclosed that minimizes the sealing part.

[0003] For example, Japanese Patent Laid-Open No. 2019-021636 discloses a storage device sheet, characterized in that it comprises a positive electrode side sheet body, a negative electrode side sheet body and a separator arranged between the positive electrode side sheet body and the negative electrode side sheet body, the positive electrode side sheet body comprises: a first metal foil layer, a positive electrode active material layer stacked on a partial area of ​​one surface of the first metal foil layer, a first thermoplastic resin layer provided on the peripheral portion of the one surface of the first metal foil layer where the positive electrode active material layer is not formed, and a first insulating resin film layer stacked on the other surface of the first metal foil layer, the negative electrode side sheet body comprises: a second metal foil layer, a negative electrode active material layer stacked on a partial area of ​​one surface of the second metal foil layer, and a first insulating resin film layer provided on the one surface of the second metal foil layer. A second thermoplastic resin layer is formed on the peripheral portion of each surface where the negative electrode active material layer is not formed, and a second insulating resin film layer is stacked on the other surface of the second metal foil layer, the positive electrode active material layer is arranged between the first metal foil layer and the separator, and the negative electrode active material layer is arranged between the second metal foil layer and the separator, the first thermoplastic resin layer of the positive electrode side sheet body and the second thermoplastic resin layer of the negative electrode side sheet body are fused to form a peripheral sealing layer, the two sheets are stacked together, an electrolyte is sealed between the separator and the positive electrode active material layer, and an electrolyte is sealed between the separator and the negative electrode active material layer, and the peripheral portion of the separator invades and is engaged with the middle portion of the inner circumference of the peripheral sealing layer in the thickness direction. According to the storage device sheet of Japanese Patent Publication No. 2019-021636, the first metal foil layer constituting the positive electrode portion and the second metal foil layer constituting the negative electrode portion also function as exterior materials of the storage device, that is, the first and second metal foil layers play the dual functions of electrodes and exterior materials, and therefore, in this structure, no exterior material is required (the previous exterior material becomes unnecessary), so as a storage device, it is possible to achieve lightness, thinness, and space saving, and also reduce costs.

[0004] Japanese Patent Application Laid-Open No. 2013-114929 discloses a thin battery, characterized in that it comprises: a power generation element, two outer casings for sealing the power generation element, a positive electrode collector terminal connected to a positive electrode collector portion of the power generation element and covering at least a portion of at least one of two outer side surfaces in a stacking direction of the power generation element, and a negative electrode collector terminal connected to a negative electrode collector portion of the power generation element and covering at least a portion of at least one of two outer side surfaces in a stacking direction of the power generation element, wherein one side of the outer periphery of the power generation element where at least the positive electrode collector portion and the negative electrode collector portion are provided is wrapped by one or both of the two outer casings that are bent, the two outer casings are bonded to each other at the two outer side surfaces in the stacking direction of the power generation element by a first bonding, and the two outer casings are bonded to each other at the outer side of the power generation element at a side of the outer periphery of the power generation element that is not wrapped by the two bent outer casings by a second bonding, and the bonding surface of the first bonding is wider than the bonding surface of the second bonding. According to the thin battery of Japanese Patent Laid-Open No. 2013-114929, since two outer casings are bonded to the outer sides of the stacking direction of the power generation element at least a part of which is covered by the positive collector terminal and the negative collector terminal, the sealing strength of the part where the positive collector terminal and the negative collector terminal are provided can be enhanced. In addition, even if the conductive member penetrates from the outside of the battery, since the current flows from the positive collector part to the negative collector part via the positive collector terminal, the conductive member, and the negative collector terminal, it is possible to prevent the current from concentrating in the internal short circuit part, thereby suppressing the increase in battery temperature. Summary of the invention

[0005] In these prior arts, it is believed that the energy density per unit area can be increased by reducing the sealing portion by folding the current collector or laminate film to include the electrode active material layer, etc. However, since the thickness of the unit increases due to the folded portion and the sealing portion, it is believed that there is room for improvement in the energy density per unit volume.

[0006] Therefore, an object of the present disclosure is to provide a single cell capable of improving energy density per unit area and energy density per unit volume.

[0007] The present disclosure achieves the above-mentioned objectives through the following means.

[0008] <Mode 1> A single cell comprising a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer stacked in this order,

[0009] When viewed in the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region.

[0010] The first electrode active material layer is laminated only on the inner region.

[0011] The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member on the peripheral region to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

[0012] <Mode 2> According to the single cell described in Mode 1, in the stacking direction, the thickness of the joint between the first collector layer, the insulating sealing member and the second collector layer is less than or equal to the total thickness of the first collector layer and the first electrode active material layer.

[0013] <Mode 3> According to the single cell described in Mode 1, in the above-mentioned joint, the above-mentioned first collector layer, the above-mentioned insulating sealing member and the above-mentioned second collector layer are stacked in the order of the above-mentioned first collector layer, the above-mentioned insulating sealing member and the above-mentioned second collector layer from the side away from the above-mentioned electrolyte layer.

[0014] <Mode 4> According to the single cell described in Mode 1, in the above-mentioned joint, the above-mentioned first collector layer, the above-mentioned insulating sealing member and the above-mentioned second collector layer, the above-mentioned insulating sealing member and the above-mentioned first collector layer are stacked in this order from the side away from the above-mentioned electrolyte layer.

[0015] <Aspect 5> The cell according to any one of aspects 1 to 4, wherein the electrolyte layer is a solid electrolyte layer.

[0016] <Mode 6> A method for manufacturing a single cell, wherein the single cell is formed by sequentially stacking a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer, the manufacturing method comprising the following steps:

[0017] Providing a stack of a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer, wherein, when viewed from the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region that is further inward than the peripheral region, and the first electrode active material layer is stacked only on the inner region; and

[0018] The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member on the peripheral region to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

[0019] According to the present disclosure, a single cell capable of improving energy density per unit area and energy density per unit volume can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings, in which like reference numerals denote like elements.

[0021] Figure 1A This is a schematic diagram showing a first electrode active material layer, an electrolyte layer, and a second electrode active material layer for explaining a single cell of the present disclosure when viewed from a stacking direction.

[0022] Figure 1B This is a schematic diagram showing a first electrode active material layer, an electrolyte layer, and a second electrode active material layer for explaining a single cell of the present disclosure when viewed from a stacking direction.

[0023] Figure 2 It is a schematic cross-sectional view for explaining a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a single cell of the present disclosure.

[0024] Figure 3 It is a schematic cross-sectional view of a single cell for explaining the present disclosure.

[0025] Figure 4 It is a schematic cross-sectional view of a single cell for explaining another embodiment of the present disclosure.

[0026] Figure 5A This is a schematic cross-sectional view for explaining a single cell produced in Example 1.

[0027] Figure 5B This is a schematic cross-sectional view for explaining a single cell produced in Example 1.

[0028] Figure 5C This is a schematic cross-sectional view for explaining a single cell produced in Example 1.

[0029] Figure 5D This is a schematic cross-sectional view for explaining a single cell produced in Example 1.

[0030] Fig. 6AIt is a schematic cross-sectional view for explaining a cell other than the cell of the present disclosure, the end of the cell being sealed by an insulating sealing member and having a sealing portion in the stacking direction.

[0031] Figure 6B It is a schematic cross-sectional view for explaining a cell other than the cell of the present disclosure, the end of the cell being sealed by an insulating sealing member and having a sealing portion in the stacking direction. DETAILED DESCRIPTION

[0032] Hereinafter, the embodiments of the present disclosure are described in detail. Furthermore, the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure. In addition, in the description of the drawings, the same elements are given the same symbols, and repeated descriptions are omitted.

[0033] Single battery

[0034] The single cell disclosed in the present invention is formed by laminating a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer in this order.

[0035] When viewed in the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region.

[0036] The first electrode active material layer is laminated only on the inner region.

[0037] The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member on the peripheral region to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

[0038] According to the present disclosure, a single cell capable of improving energy density per unit area and energy density per unit volume can be provided.

[0039] Specifically, for example Figure 3 As shown, in the single cell disclosed in the present invention, the electrolyte layer 12 and the second electrode active material layer 13 are enclosed by the second collector layer 14, and on the peripheral area 12a of the electrolyte layer 12, the first collector layer 10 and the second collector layer 14 form a joint through an insulating sealing component 15, thereby, the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13 are sealed.

[0040] The battery is formed by enclosing the electrode stack with the second current collector layer 14 and sealing the electrode stack with an insulating sealing member. Fig. 6A By comparison, the area of ​​the insulating sealing member can be reduced, and the area occupied by the first electrode active material layer and the second electrode active material layer in the area of ​​the single cell can be increased. Therefore, it is believed that when using an electrode stack with the same energy density, the energy density per unit area of ​​the single cell can be increased.

[0041] In addition, the first collector layer 10 and the second collector layer 14 form a joint in the peripheral region 12a of the electrolyte layer 12. That is, the joint is arranged at a position parallel to at least a portion of the first electrode active material layer 11 in the thickness direction. Therefore, it is similar to a battery in which the collector layers are wound and sealed in the stacking direction, specifically, for example Figure 6B In contrast, the cell of the present disclosure can suppress an increase in thickness. Therefore, it is considered that the energy density per unit volume of the cell can be increased when an electrode stack having the same energy density is used.

[0042] Laminated body of first electrode active material layer, electrolyte layer and second electrode active material layer

[0043] In the single cell of the present disclosure,

[0044] When viewed in the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region.

[0045] The first electrode active material layer is laminated only on the inner region.

[0046] Figure 1A This is an example of a schematic diagram of a stack of an electrolyte layer and a second electrode active material layer of a single cell of the present disclosure as viewed from the stacking direction. Figure 1B This is an example of a schematic diagram of a stack of the first electrode active material layer, the electrolyte layer, and the second electrode active material layer of the unit cell of the present disclosure as viewed from the stacking direction, but the present invention is not limited to this case. Figure 2 This is an example of a schematic cross-sectional view showing a stacked body of a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a single cell of the present disclosure, but the present invention is not limited to this case.

[0047] use Figure 1A , Figure 1B , Figure 2 , a laminate of a first electrode active material layer, an electrolyte layer, and a second electrode active material layer is described. Figure 1AIn the schematic diagram when viewed in the stacking direction, in the stack of the electrolyte layer 12 and the second electrode active material layer 13, the electrolyte layer 12 and the second electrode active material layer 13 have a peripheral region 12a outside the dotted line shown in the electrolyte layer 12 and an inner region 12b inside the dotted line. Figure 1B In the schematic diagram when viewed in the stacking direction, the first electrode active material layer 11 is stacked only on the inner region 12b of the electrolyte layer. Since the first electrode active material layer 11 is stacked only on the inner region 12b, the area of ​​the first electrode active material layer 11 is smaller than that of the electrolyte layer 12 and the second electrode active material layer 13. Figure 3 In the cross-sectional view of , since the first electrode active material layer 11 is not stacked in the peripheral region 12a of the electrolyte layer 12, the stacked body including the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13 has a convex shape.

[0048] Sealing by the second current collector layer and the first current collector layer

[0049] The second collector layer disclosed in the present invention is folded to include the above-mentioned electrolyte layer and the above-mentioned second electrode active material layer inside, and is joined to the above-mentioned first collector layer through an insulating sealing component on the above-mentioned peripheral area to form a joint portion, thereby, the above-mentioned first electrode active material layer, the above-mentioned electrolyte layer and the above-mentioned second electrode active material layer are sealed by the above-mentioned first collector layer, the above-mentioned insulating sealing component and the above-mentioned second collector layer.

[0050] Insulating sealing components

[0051] The insulating sealing member may be made of any material that can bond the first current collector layer and the second current collector layer together and achieve electrical insulation.

[0052] The above-mentioned insulating sealing member is not particularly limited, and thermoplastic resin, rubber, non-conductive adhesive, etc. can be used. As a thermoplastic resin, specifically, polyethylene terephthalate (PET), polypropylene (PP), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polycarbonate (PC) or polyetherimide (PEI), etc. can be cited, but it is not limited to this. As rubber, specifically, acrylonitrile butadiene rubber (ABR) or butadiene rubber (SB), etc. can be cited, but it is not limited to this. As a non-conductive adhesive, specifically, epoxy adhesive or acrylic adhesive, etc. can be cited, but it is not limited to this. In addition, the above-mentioned insulating sealing member can also use insulating metal oxides, specifically, aluminum oxide, zirconium oxide, calcium oxide or magnesium oxide, etc. can be used. In addition, any combination of the above-mentioned materials can also be used.

[0053] Figure 3This is an example of a schematic cross-sectional view of a single cell of the present disclosure, but the present disclosure is not limited thereto.

[0054] A second collector layer 14 is provided below the stack of the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13. The second collector layer 14 is folded in such a manner that the electrolyte layer 12 and the second electrode active material layer 13 are contained inside. The folded end of the second collector layer 14 is arranged on the peripheral region 12a of the electrolyte layer 12, and is arranged in such a manner that it does not contact the first electrode active material layer 11. An insulating sealing member 15 is provided above the folded end of the second collector layer 14, and the first collector layer 10 is further provided above it. The first collector layer 10 is arranged in contact with the insulating sealing member 15 and the first electrode active material layer 11. A joint is formed by the first collector layer 10, the insulating sealing member 15, and the second collector layer 14. Thus, the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13 are sealed by the first collector layer 10, the insulating sealing member 15, and the second collector layer 14. Since the joint is located on the peripheral region 12a of the electrolyte layer 12, it is believed that although the electrode active material layer and the electrolyte layer of the single cell of the present disclosure are contained inside the collector layer, the increase in the thickness of the single cell caused by the insulating sealing member and the collector layer can still be suppressed, and the energy density per unit volume of the single cell is improved.

[0055] The folded end of the second current collector is not particularly limited, as long as it exists in the peripheral region 12a of the electrolyte layer 12, and can be in contact with the electrolyte layer 12, or can be in contact with other components such as an insulating sealing member. From the viewpoint of preventing battery degradation caused by moisture, the width of the junction is not particularly limited, but is preferably 1 mm or more, 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more. In addition, the width of the junction can be 30 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less.

[0056] Components of a single battery

[0057] The unit cell disclosed in the present invention includes a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer stacked in this order.

[0058] First current collector layer

[0059] The material used for the first current collector layer is not particularly limited, and any material that can be used as a current collector for a battery can be appropriately adopted.

[0060] For example, the material used for the first collector layer may be, but is not limited to, stainless steel (SUS), aluminum, copper, nickel, iron, titanium, carbon, or a conductive resin, etc. Alternatively, it may be a material obtained by coating, plating, or vapor deposition of carbon on a metal such as aluminum, copper, SUS, nickel, iron, or titanium.

[0061] When the first current collector layer is a positive electrode current collector, the material used for the first current collector layer is not particularly limited, but preferably a current collector with oxidation resistance, more preferably aluminum. When the first current collector layer is a negative electrode current collector, the material used for the first current collector layer is not particularly limited, but preferably a current collector with reduction resistance, more preferably nickel.

[0062] The first current collector layer may be in any shape that can be joined to the second current collector layer to form an outer package. Examples of such a shape include a foil shape, but are not particularly limited.

[0063] From the viewpoint of forming an outer casing, the first current collector layer is preferably formed of a material that is difficult for water to permeate.

[0064] First electrode active material layer

[0065] The first electrode active material layer may be a negative electrode active material layer or a positive electrode active material layer.

[0066] The first electrode active material layer may contain an electrode active material and optionally a solid electrolyte, a conductive auxiliary agent, and a binder.

[0067] When the first electrode active material layer is a positive electrode active material layer, the electrode active material is a positive electrode active material.

[0068] The material of the positive electrode active material is not particularly limited. For example, the positive electrode active material can be lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, by Li 1+x Mn 2-x-y M y A heterogeneous element-substituted Li-Mn spinel having a composition represented by O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni and Zn) is used, but is not limited to these.

[0069] When the first electrode active material layer is a negative electrode active material layer, the electrode active material is a negative electrode active material.

[0070] The material of the negative electrode active material is not particularly limited, and may be metallic lithium or a material capable of embedding and deintercalating metal ions such as lithium ions. As the material capable of embedding and deintercalating metal ions such as lithium ions, for example, alloy-based negative electrode active materials or carbon materials may be cited, but are not limited thereto.

[0071] There is no particular limitation on alloy-based negative electrode active materials, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, or their solid solutions. In addition, Si alloy-based negative electrode active materials may contain elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. Sn alloy-based negative electrode active materials include tin, tin oxide, tin nitride, or their solid solutions. In addition, Sn alloy-based negative electrode active materials may contain elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc. Among them, Si alloy-based negative electrode active materials are preferred.

[0072] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, and graphite.

[0073] Solid Electrolyte

[0074] The material of the solid electrolyte is not particularly limited. For example, the solid electrolyte may be a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte, but is not limited thereto.

[0075] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, and argyrodite-type solid electrolytes. Examples of specific sulfide solid electrolytes include Li2S-P2S5 (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2 (Li 13 GeP3S 16 , Li 10 GeP2S 12 etc.), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc.; or combinations thereof, but not limited thereto.

[0076] As an example of oxide solid electrolyte, Li7La3Zr2O12 , Li 7-x Ln3Z 1-x Nb x O 12 , Li 7- 3x La3Zr2Al x O 12 , Li 3x La 2 / 3-x TiO3、Li 1+x Al x Ti 2-x (PO4)3、Li 1+x Al x Ge 2-x (PO4)3, Li3PO4 or Li 3+x PO 4-x N x (LiPON), etc., but not limited to these.

[0077] The sulfide solid electrolyte and the oxide solid electrolyte may be glass or crystallized glass (glass ceramic).

[0078] Examples of the polymer electrolyte include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof, but the polymer electrolyte is not limited thereto.

[0079] Conductive additives

[0080] The conductive additive is not particularly limited, and may be, for example, a carbon material such as VGCF (vapor grown carbon fiber) or carbon nanofiber, or a metal material, but is not limited thereto.

[0081] Adhesives

[0082] The binder is not particularly limited, and may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), or a combination thereof, but is not limited thereto.

[0083] Electrolyte layer

[0084] The electrolyte layer of the present disclosure may be a solid electrolyte layer.

[0085] When the electrolyte layer is a solid electrolyte layer, the solid electrolyte layer may contain a binder etc. as required in addition to the solid electrolyte. The solid electrolyte and the binder may refer to the description of the "first electrode active material layer" mentioned above.

[0086] Second electrode active material layer

[0087] Regarding the second electrode active material layer, reference can be made to the description of the above-mentioned “first electrode active material layer”.

[0088] Furthermore, the polarities of the first electrode active material layer and the second electrode active material layer are opposite to each other. That is, if the first electrode active material layer is a positive electrode active material layer, the second electrode active material layer is a negative electrode active material layer. Similarly, if the first electrode active material layer is a negative electrode active material layer, the second electrode active material layer is a positive electrode active material layer.

[0089] Second current collector layer

[0090] The second current collector layer may also be formed of the material described in the above-mentioned “first current collector layer”.

[0091] The second current collector layer may be in any shape that allows the stacked body to be wound so as to contain the first electrode active material layer, the electrolyte layer, and the second electrode active material layer. Examples of such shapes include foil, but are not limited thereto.

[0092] Furthermore, the polarities of the first collector layer and the second collector layer are opposite to each other. That is, if the first collector layer is a positive electrode collector layer, the second collector layer is a negative electrode collector layer. Similarly, if the first collector layer is a positive electrode collector layer, the second collector layer is a negative electrode collector layer.

[0093] Thickness of joint

[0094] The thickness of each component of the single cell disclosed in the present invention, in the stacking direction, the thickness of the junction of the first current collector layer, the insulating sealing member, and the second current collector layer may be less than or equal to the total thickness of the first current collector layer and the first electrode active material layer. For example, the thickness of the junction of the first current collector layer, the insulating sealing member, and the second current collector layer may be less than 100%, less than 95%, less than 90%, or less than 85% of the total thickness of the first current collector layer and the first electrode active material layer, and may be more than 50%, more than 60%, more than 70%, or more than 80%.

[0095] From the viewpoint of suppressing the increase of the thickness of the single cell by making the junction present in the peripheral region, the thickness of the junction is not particularly limited, but is preferably less than or equal to the total thickness of the first collector layer and the first electrode active material layer. Here, the thickness of the junction is the total thickness of the first collector layer, the insulating sealing member, and the second collector layer.

[0096] For example, in the above Figure 3, the total thickness 16 of the joint is the total thickness of the first collector layer 10 , the insulating sealing component 15 and the second collector layer 14 , and the total thickness 17 of the first collector layer and the first electrode active material layer is the total thickness of the first collector layer 10 and the first electrode active material layer 11 .

[0097] Insulating fixing member

[0098] As a member of the single cell, an insulating fixing member may be further included. For specific materials of the insulating fixing member, reference may be made to the description of the "insulating sealing member".

[0099] The shape of the joint

[0100] In the unit cell disclosed herein, in the joint portion, the first current collector layer, the insulating sealing member, and the second current collector layer may be stacked in this order from a side farther from the electrolyte layer.

[0101] For example, in the above Figure 3 In the single cell, the peripheral region 12a of the electrolyte layer 12 has a junction formed by the first collector layer 10, the insulating sealing member 15, and the second collector layer 14. Figure 3 In the embodiment, the first collector layer 10, the insulating sealing member 15 and the second collector layer 14 are stacked in this order from the side away from the electrolyte layer 12. The second collector layer 14 close to the electrolyte layer 12 may be in direct contact with the electrolyte layer 12 or may be in contact with the electrolyte layer 12 via other members such as an insulating fixing member.

[0102] Other forms of joints

[0103] In the unit cell disclosed herein, in the joint portion, the first current collector layer, the insulating sealing member, and the second current collector layer may be stacked in this order from the side away from the electrolyte layer.

[0104] Figure 4 This is an example of a schematic cross-sectional view of a single cell of the present disclosure, but the present disclosure is not limited thereto.

[0105] The peripheral region 12a of the electrolyte layer 12 has a junction formed by the first current collector layer 10, the insulating sealing member 15, and the second current collector layer 14. Figure 4In the embodiment, the second collector layer 14, the insulating sealing member 15 and the first collector layer 10 are stacked in this order from the side away from the electrolyte layer 12. The first collector layer 10 close to the electrolyte layer 12 may be in direct contact with the electrolyte layer 12 or may be in contact with the electrolyte layer 12 via other members such as an insulating fixing member.

[0106] Method for manufacturing single battery

[0107] In the manufacturing method of the single cell disclosed in the present invention, the single cell is formed by sequentially stacking a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer, and the manufacturing method comprises the following steps:

[0108] Providing a stack of a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer, wherein, when viewed from the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region that is further inward than the peripheral region, and the first electrode active material layer is stacked only on the inner region; and

[0109] The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member on the peripheral region to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

[0110] According to the manufacturing method of the single cell of the present disclosure, a single cell having improved energy density per unit area and energy density per unit volume can be provided. For details of the single cell manufactured by the manufacturing method of the single cell of the present disclosure, reference can be made to the description of the single cell of the present disclosure.

[0111] The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0112] Example 1

[0113] Preparation of LiNi containing as positive electrode active material 1 / 3 Co 1 / 3 Mn 1 / 3 , a positive electrode mixture of LiI-LiBr-Li2S-P2S5 as a solid electrolyte, VGCF (vapor-grown carbon fiber) as a conductive aid and SBR (styrene butadiene rubber) as a binder, and a positive electrode active material layer as the first electrode active material layer is obtained from the positive electrode mixture.

[0114] In addition, a negative electrode mixture containing graphite as a negative electrode active material, LiI-LiBr-Li2S-P2S5 as a solid electrolyte and SBR as a binder is prepared, and a negative electrode active material layer as a second electrode active material layer is obtained from the negative electrode mixture.

[0115] Furthermore, a solid electrolyte mixture containing LiI-LiBr-Li2S-P2S5 as a solid electrolyte and SBR as a binder is prepared, and a solid electrolyte layer as an electrolyte layer is obtained from the solid electrolyte mixture.

[0116] like Figure 5A As shown in the figure, the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are stacked to obtain an electrode stack. Furthermore, the negative electrode active material layer and the solid electrolyte layer have a peripheral region and an inner region that is closer to the inner side than the peripheral region, and the positive electrode active material layer is only stacked on the inner region of the solid electrolyte layer.

[0117] The electrode stack is arranged on the nickel foil so that the negative electrode active material layer is in contact with the nickel foil as the second current collector layer. Figure 5B As shown, the solid electrolyte layer is covered from the peripheral region to the nickel foil by a PP (polypropylene) film as an insulating fixing member. Next, the entirety is heated (150° C. for 1 minute) to temporarily fix the electrode stack to the nickel foil.

[0118] like Figure 5C As shown in FIG. 1 , the nickel foil is folded along the PP film as the insulating fixing member. Figure 5D As shown, a PP film as an insulating sealing member is placed on the folded nickel foil in the peripheral region, and an aluminum foil as a first current collector layer is placed thereon so as to be in contact with the PP film and the positive electrode active material layer placed in the peripheral region.

[0119] Then, by heating the whole (160°C and 1 minute), the nickel foil forms a joint with the aluminum foil in the peripheral area, thereby obtaining a single cell in which the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are sealed, and the outer body is formed by the first collector layer and the second collector layer. Here, the width of the joint is 3 mm, and the thickness of the joint is 100% of the total thickness of the first collector layer and the first electrode active material layer.

[0120] Although preferred embodiments of the single cell of the present disclosure have been described, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the claims.

Claims

1. A single cell, wherein a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer are stacked in sequence. When viewed in the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region. The first electrode active material layer is laminated only on the inner region, The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member in the peripheral area to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

2. The single cell according to claim 1, In the stacking direction, a thickness of the junction of the first current collector layer, the insulating sealing member, and the second current collector layer is less than or equal to a total thickness of the first current collector layer and the first electrode active material layer.

3. The single cell according to claim 1, In the junction, the first current collector layer, the insulating sealing member, and the second current collector layer are stacked in this order from a side farther from the electrolyte layer.

4. The single cell according to claim 1, In the junction, the first current collector layer, the insulating sealing member, and the second current collector layer are stacked in this order from a side farther from the electrolyte layer.

5. The single cell according to any one of claims 1 to 4, The electrolyte layer is a solid electrolyte layer.

6. A method for manufacturing a single cell, wherein the single cell is formed by sequentially stacking a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer, the manufacturing method comprising the following steps: A laminate of a first current collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second current collector layer is provided, wherein: When viewed from the stacking direction of the layers constituting the single cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region that is inside the peripheral region, and the first electrode active material layer is stacked only on the inner region; and The second current collector layer is folded to include the electrolyte layer and the second electrode active material layer inside, and the second current collector layer is joined to the first current collector layer via an insulating sealing member on the peripheral area to form a joint, thereby sealing the first electrode active material layer, the electrolyte layer and the second electrode active material layer with the first current collector layer, the insulating sealing member and the second current collector layer.

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