Electric cell

Abstract

To provide an electric cell capable of improving energy density per unit area and energy density per unit volume.SOLUTION: An electric cell comprises a first collector layer, a first electrode active material layer, an electrolyte layer, a second electrode active material layer, and a second collector layer which are laminated in this order. The first electrode active material layer is laminated only on an inner region. The second collector layer is folded so as to include the electrolyte layer and the second electrode active material layer, and on a peripheral region, it is also bonded to the first collector layer via an insulative sealing member so as to form a bonding part. As a result, the first electrode active material layer, the electrolyte layer, and the second electrode active material layer are sealed by the first collector layer, the insulative sealing member, and the second collector layer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to thin cell batteries. [Background technology]

[0002] In recent years, as mobile devices and other devices have become thinner, the batteries used in these devices have also been required to be thinner and smaller. A known thin battery is one in which a single cell is sandwiched between two laminate films and the edges are heat-sealed to seal the edges. By sealing the edges of this thin battery, deterioration of the battery due to moisture can be suppressed, but because the sealed area is unrelated to charging and discharging, it is necessary to make the sealed area as small as possible from the perspective of energy density. The following energy storage devices have been disclosed that use thin and small batteries with sealed areas as small as possible.

[0003] For example, Patent Document 1 discloses a positive electrode-side sheet body including a first metal foil layer, a positive electrode active material layer laminated on a partial region of one surface of the first metal foil layer, a first thermoplastic resin layer provided on a 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 laminated on the other surface of the first metal foil layer; a negative electrode-side sheet body including a second metal foil layer, a negative electrode active material layer laminated on a partial region of the one surface of the second metal foil layer, a second thermoplastic resin layer provided on a peripheral portion of the one surface of the second metal foil layer where the negative electrode active material layer is not formed, and a second insulating resin film layer laminated on the other surface of the second metal foil layer; and a separator arranged between the negative electrode side sheet body and the positive electrode active material layer, the positive electrode active material layer being arranged between the first metal foil layer and the separator, the negative electrode active material layer being arranged between the second metal foil layer and the separator, a first thermoplastic resin layer of the positive electrode side sheet body and a second thermoplastic resin layer of the negative electrode side sheet body being fused together to form a peripheral sealing layer, and the two sheet bodies being laminated together, an electrolyte solution being sealed between the separator and the positive electrode active material layer, an electrolyte solution being sealed between the separator and the negative electrode active material layer, and the peripheral portion of the separator penetrating into and engaging with a middle portion of the inner peripheral surface of the peripheral sealing layer in the thickness direction. According to the electricity storage device sheet of Patent Document 1, the first metal foil layer constituting the positive electrode part and the second metal foil layer constituting the negative electrode part also function as the exterior material of the electricity storage device; in other words, the first and second metal foil layers function as both electrodes and exterior materials. Therefore, this configuration does not require any additional exterior material (conventional exterior materials are no longer necessary), and it is said that the electricity storage device can be made lighter, thinner, and more space-saving, while also reducing costs.

[0004] Patent Document 2 discloses a thin battery comprising: a power generating element; two exterior bodies for sealing the power generating element; a positive electrode current collecting terminal connected to the positive electrode current collecting part of the power generating element and covering at least a portion of at least one of the two outer surfaces in the stacking direction of the power generating element; and a negative electrode current collecting terminal connected to the negative electrode current collecting part of the power generating element and covering at least a portion of at least one of the two outer surfaces in the stacking direction of the power generating element; the outer periphery of the power generating element, at least on the side where the positive electrode current collecting part and the negative electrode current collecting part are provided, is enclosed by one or both of the two folded exterior bodies, and the two exterior bodies are bonded together at both outer surfaces in the stacking direction of the power generating element by a first bonding; and the outer periphery of the power generating element, whose axis is the stacking direction, is not enclosed by the two folded exterior bodies, is bonded together by a second bonding on the outside of the power generating element by bonding the two exterior bodies, and the bonding surface of the first bonding is wider than the bonding surface of the second bonding. According to the thin battery in Patent Document 2, two exterior bodies are bonded to both outer surfaces in the stacking direction of the power generating element, which is at least partially covered by the positive and negative current collector terminals, thereby strengthening the seal strength at the portions where the positive and negative current collector terminals are provided. Furthermore, even if a conductive member is pierced from the outside of the battery, current flows from the positive current collector to the negative current collector via the positive current collector terminal, the conductive member, and the negative current collector terminal, preventing current concentration at the internal short-circuit and suppressing an increase in battery temperature. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-021636 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-114929 Summary of the Invention [Problem to be solved by the invention]

[0006] In these prior arts, the current collector, laminate film, etc. are folded while enclosing the electrode active material layer, etc., thereby making it possible to reduce the size of the sealed portion, which is thought to improve the energy density per unit area. However, since the folded portions and sealed portion increase the thickness of the cell, it is thought that there is room for improvement in the energy density per unit volume.

[0007] Therefore, an object of the present disclosure is to provide a cell that can improve the energy density per unit area and the energy density per unit volume. [Means for solving the problem]

[0008] The present disclosure achieves the above object by the following means.

[0009] <Aspect 1> A single cell having 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, when viewed from a stacking direction of the layers constituting the unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located more inward than the peripheral region, the first electrode active material layer is laminated only on the inner region, the second current collector layer is folded so as to enclose the electrolyte layer and the second electrode active material layer, and is joined to the first current collector layer on the peripheral region via an insulating sealing member to form a joint, whereby 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; Single battery. <Aspect 2> The cell of Aspect 1, wherein the thickness of the joint between the first current collector layer, the insulating sealing member, and the second current collector layer in the stacking direction is equal to or smaller than the total thickness of the first current collector layer and the first electrode active material layer. <Aspect 3> The cell of Aspect 1, wherein the first current collector layer, the insulating sealing member, and the second current collector layer are stacked in the joint in the following order from the side farthest from the electrolyte layer: the first current collector layer, the insulating sealing member, and the second current collector layer. <Aspect 4> The cell of Aspect 1, wherein the first current collector layer, the insulating sealing member, and the second current collector layer are stacked in the following order from the side farthest from the electrolyte layer: the second current collector layer, the insulating sealing member, and the first current collector layer. Aspect 5: The cell according to any one of Aspects 1 to 4, wherein the electrolyte layer is a solid electrolyte layer. <Aspect 6> A method for producing a 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 method comprising: a laminate including 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 unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region, and the first electrode active material layer is laminated only on the inner region; folding the second current collector layer so as to enclose the electrolyte layer and the second electrode active material layer, and joining the second current collector layer to the first current collector layer on the peripheral region via an insulating sealing member 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; A method for manufacturing a cell comprising: [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide a cell that can improve the energy density per unit area and the energy density per unit volume. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a schematic diagram illustrating a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a cell of the present disclosure, viewed from the stacking direction. [Figure 2] FIG. 2 is a schematic cross-sectional view illustrating a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a cell of the present disclosure. [Figure 3] FIG. 3 is a schematic cross-sectional view illustrating a cell of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating a unit cell according to another embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic cross-sectional view illustrating the unit cell produced in Example 1. As shown in FIG. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating a cell other than the cell of the present disclosure, the cell having edges sealed with an insulating sealing member, and the cell having a sealing portion in the stacking direction. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure. In addition, in the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted.

[0013] 《Single battery》 The cell of the present disclosure comprises: A single battery 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, when viewed from a stacking direction of the layers constituting the unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located more inward than the peripheral region, the first electrode active material layer is laminated only on the inner region, the second current collector layer is folded so as to enclose the electrolyte layer and the second electrode active material layer, and is joined to the first current collector layer on the peripheral region via an insulating sealing member to form a joint, whereby 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; It is a single battery.

[0014] According to the present disclosure, it is possible to provide a cell that can improve the energy density per unit area and the energy density per unit volume.

[0015] Specifically, for example, as shown in FIG. 3 , in the battery of the present disclosure, an electrolyte layer 12 and a second electrode active material layer 13 are enclosed within a second current collector layer 14, and a first current collector layer 10 and a second current collector layer 14 form a joint on a peripheral region 12 a of the electrolyte layer 12 via an insulating sealing member 15, thereby sealing the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13.

[0016] By enclosing the electrode laminate in the second current collector layer 14, the area of ​​the insulating sealing member can be reduced and the area of ​​the first electrode active material layer and the second electrode active material layer relative to the area of ​​the unit cell can be increased compared to a battery in which the periphery of the electrode laminate is sealed with an insulating sealing member, specifically, for example, as shown in Fig. 6(B). As a result, when an electrode laminate having the same energy density is used, it is thought that it is possible to improve the energy density per unit area of ​​the unit cell.

[0017] Furthermore, the first current collector layer 10 and the second current collector layer 14 form a joint on the peripheral region 12a of the electrolyte layer 12. That is, the joint is disposed in a position parallel to at least a portion of the first electrode active material layer 11 in the thickness direction. Therefore, compared to a battery in which the current collector layers are wound and sealed in the stacking direction, specifically, for example, as shown in FIG. 6(C), the unit cell of the present disclosure can suppress an increase in thickness. As a result, when an electrode stack having the same energy density is used, it is believed that the energy density per unit volume of the unit cell can be improved.

[0018] <Laminate of First Electrode Active Material Layer, Electrolyte Layer, and Second Electrode Active Material Layer> In the battery cell of the present disclosure, When viewed from the stacking direction of the layers constituting the unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region that is located more inward than the peripheral region, A first electrode active material layer is laminated only on the inner region.

[0019] Fig. 1A is an example of a schematic diagram of a laminate of an electrolyte layer and a second electrode active material layer of a battery according to the present disclosure, viewed from the stacking direction, Fig. 1B is an example of a schematic diagram of a laminate of a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a battery according to the present disclosure, viewed from the stacking direction, but this is not limited to this example. Fig. 2 is an example of a schematic diagram of a cross section showing a laminate of a first electrode active material layer, an electrolyte layer, and a second electrode active material layer of a battery according to the present disclosure, but this is not limited to this example.

[0020] A stack of a first electrode active material layer, an electrolyte layer, and a second electrode active material layer will be described with reference to Figures 1 and 2. In the schematic diagram of Figure 1A, viewed from the stacking direction, in a stack of an electrolyte layer 12 and a 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 on the electrolyte layer 12 and an inner region 12b inside the dotted line. In the schematic diagram of Figure 1B, viewed from the stacking direction, the first electrode active material layer 11 is stacked only on the inner region 12b of the electrolyte layer. Because 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. In the cross-sectional view of Figure 3, the first electrode active material layer 11 is not stacked in the peripheral region 12a of the electrolyte layer 12, so the stack in which the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13 are stacked has a convex shape.

[0021] <Sealing with the second current collector layer and the first current collector layer> The second current collector layer of the present disclosure is folded so as to enclose the electrolyte layer and the second electrode active material layer, and is joined to the first current collector layer on the peripheral region via an insulating sealing member to form a joint, whereby the first current collector layer, the insulating sealing member, and the second current collector layer seal the first electrode active material layer, the electrolyte layer, and the second electrode active material layer.

[0022] (insulating sealing material) The insulating sealing member can be made of any material that can bond the first current collector layer and the second current collector layer and can provide electrical insulation.

[0023] The insulating sealing member may be made of, but is not limited to, a thermoplastic resin, rubber, a non-conductive binder, or the like. Examples of the thermoplastic resin include, but are not limited to, polyethylene terephthalate (PET), polypropylene (PP), polyvinylidene chloride (PVDC), polyvinylidene fluoride (PVDF), polycarbonate (PC), and polyetherimide (PEI). Examples of the rubber include, but are not limited to, acrylonitrile butadiene rubber (ABR) and butadiene rubber (SB). Examples of the non-conductive binder include, but are not limited to, an epoxy binder or an acrylic binder. The insulating sealing member may also be made of, for example, an insulating metal oxide, such as alumina, zirconia, calcium oxide, or magnesium oxide. Any combination of the above materials may also be used.

[0024] FIG. 3 is one example of a schematic cross-sectional view showing a cell of the present disclosure, but is not limited to this case.

[0025] A second current collector layer 14 is provided below the laminate of the first electrode active material layer 11, the electrolyte layer 12, and the second electrode active material layer 13. The second current collector layer 14 is folded so as to enclose the electrolyte layer 12 and the second electrode active material layer 13. The folded ends of the second current collector layer 14 are disposed on the peripheral region 12a of the electrolyte layer 12 and are disposed so as not to contact the first electrode active material layer 11. An insulating sealing member 15 is provided on each folded end of the second current collector layer 14, and a first current collector layer 10 is further provided thereon. The first current collector layer 10 is disposed in contact with the insulating sealing member 15 and the first electrode active material layer 11. A joint is formed by the first current collector layer 10, the insulating sealing member 15, and the second current collector layer 14. As a result, the first electrode active material layer 11, electrolyte layer 12, and second electrode active material layer 13 are sealed by the first current collector layer 10, insulating sealing member 15, and second current collector layer 14. Because the joint is located on the peripheral region 12a of the electrolyte layer 12, the battery of the present disclosure is thought to be able to suppress an increase in the thickness of the battery due to the insulating sealing member and current collector layer, even though the electrode active material layer and electrolyte layer are enclosed by the current collector layer, thereby improving the energy density per unit volume of the battery.

[0026] The folded end of the second current collector is not particularly limited as long as it is present in the peripheral region 12a of the electrolyte layer 12. It may be in contact with the electrolyte layer 12 or may be in contact via another member such as an insulating sealing member. From the viewpoint of preventing battery deterioration due to moisture, the width of the joint 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. The width of the joint may also be 30 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less.

[0027] <Components of a Cell> The cell of the present disclosure has 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.

[0028] <First current collector layer> The material used for the first current collector layer is not particularly limited, but any material that can be used as a current collector for a battery can be appropriately used.

[0029] For example, the material used for the first current collector layer may be, but is not limited to, stainless steel (SUS), aluminum, copper, nickel, iron, titanium, carbon, or a conductive resin. Furthermore, the first current collector layer may be made of a metal such as aluminum, copper, SUS, nickel, iron, or titanium that has been treated with carbon by coating, plating, vapor deposition, or the like.

[0030] 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 is preferably an oxidation-resistant current collector, 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 is preferably a reduction-resistant current collector, more preferably nickel.

[0031] The first current collector layer may have any shape that allows it to be joined to the second current collector layer to form an outer casing, such as, but not limited to, a foil shape.

[0032] The first current collector layer is preferably made of a material that is difficult for moisture to permeate, in view of forming an exterior body.

[0033] <First electrode active material layer> The first electrode active material layer may be a negative electrode active material layer or a positive electrode active material layer.

[0034] The first electrode active material layer may contain an electrode active material, and optionally a solid electrolyte, a conductive additive, and a binder.

[0035] When the first electrode active material layer is a positive electrode active material layer, the electrode active material is a positive electrode active material.

[0036] The material of the positive electrode active material is not particularly limited. For example, the positive electrode active material may be lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMnO), LiCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, Li 1+x Mn 2-x-y M y The material may be, but is not limited to, a different 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).

[0037] When the first electrode active material layer is a negative electrode active material layer, the electrode active material is a negative electrode active material.

[0038] The material of the negative electrode active material is not particularly limited, and may be metallic lithium or a material capable of absorbing and releasing metal ions such as lithium ions. Examples of materials capable of absorbing and releasing metal ions such as lithium ions include, but are not limited to, alloy-based negative electrode active materials and carbon materials.

[0039] The alloy-based negative electrode active material is not particularly limited, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Examples of Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, and solid solutions thereof. The Si alloy-based negative electrode active material may contain elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti. Examples of Sn alloy-based negative electrode active materials include tin, tin oxide, tin nitride, and solid solutions thereof. The Sn alloy-based negative electrode active material may contain elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, and Si. Among these, Si alloy-based negative electrode active materials are preferred.

[0040] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, and graphite.

[0041] (solid electrolyte) The material of the solid electrolyte is not particularly limited, and for example, the solid electrolyte may be a sulfide solid electrolyte, an oxide solid electrolyte, a polymer electrolyte, or the like, but is not limited to these.

[0042] 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. Specific examples of sulfide solid electrolytes include Li2S-P2S5-based (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 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc.; or combinations thereof, but are not limited to these.

[0043] An example of an oxide solid electrolyte is Li7La3Zr2O 12 , Li 7-x La3Zr 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 are not limited to these.

[0044] The sulfide solid electrolyte and the oxide solid electrolyte may be glass or crystallized glass (glass ceramic).

[0045] Examples of polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0046] (Conductive additive) 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.

[0047] (binder) The binder is not particularly limited, and may be, for example, but not limited to, a material such as polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), or styrene butadiene rubber (SBR), or a combination thereof.

[0048] <Electrolyte layer> The electrolyte layer of the present disclosure may be a solid electrolyte layer.

[0049] When the electrolyte layer is a solid electrolyte layer, the solid electrolyte layer may contain, in addition to the solid electrolyte, a binder, etc., as necessary. For the solid electrolyte and the binder, please refer to the above description of "<First electrode active material layer>".

[0050] <Second electrode active material layer> For the second electrode active material layer, reference can be made to the above description of "<First electrode active material layer>".

[0051] The first electrode active material layer and the second electrode active material layer have opposite polarities. 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.

[0052] <Second current collector layer> The second current collector layer may be formed from the materials described above in "<First current collector layer>".

[0053] The second current collector layer may have any shape that allows the laminate of the first electrode active material layer, the electrolyte layer, and the second electrode active material layer to be wound up so as to enclose the laminate, such as, but not limited to, a foil shape.

[0054] The first and second current collector layers have opposite polarities. That is, if the first current collector layer is a positive electrode current collector layer, the second current collector layer is a negative electrode current collector layer. Similarly, if the first current collector layer is a positive electrode current collector layer, the second current collector layer is a negative electrode current collector layer.

[0055] <Thickness of joint> With regard to the thickness of each component of the cell of the present disclosure, in the stacking direction, the thickness of the joint between the first current collector layer, the insulating sealing member, and the second current collector layer may be equal to or smaller than the total thickness of the first current collector layer and the first electrode active material layer. For example, the thickness of the joint between the first current collector layer, the insulating sealing member, and the second current collector layer may be 100% or less, 95% or less, 90% or less, or 85% or less of the total thickness of the first current collector layer and the first electrode active material layer, or may be 50% or more, 60% or more, 70% or more, or 80% or more.

[0056] The thickness of the joint is not particularly limited, but is preferably equal to or smaller than the total thickness of the first current collector layer and the first electrode active material layer, since the presence of the joint on the peripheral region can prevent the thickness of the unit cell from increasing. Here, the thickness of the joint is the total thickness of the first current collector layer, the insulating sealing member, and the second current collector layer.

[0057] For example, in FIG. 3 mentioned above, the total thickness 16 of the joint is the total thickness of the first current collector layer 10, the insulating sealing member 15, and the second current collector layer 14, and the total thickness 17 of the first current collector layer and the first electrode active material layer is the total thickness of the first current collector layer 10 and the first electrode active material layer 11.

[0058] (insulating fastening material) The unit cell may further include an insulating fastening member. For specific materials of the insulating fastening member, please refer to the description of "(insulating sealing member)."

[0059] <Mode of joint> In the battery of the present disclosure, the first current collector layer, the insulating sealing member, and the second current collector layer may be stacked in the joint portion in the order of the first current collector layer, the insulating sealing member, and the second current collector layer from the side farthest from the electrolyte layer.

[0060] For example, in the aforementioned unit cell shown in FIG. 3, a joint formed of a first current collector layer 10, an insulating sealing member 15, and a second current collector layer 14 is provided on the peripheral region 12a of the electrolyte layer 12. In FIG. 3, the first current collector layer 10, the insulating sealing member 15, and the second current collector layer 14 are stacked in this order from the side farthest from the electrolyte layer 12. The second current collector layer 14 closer 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 another member such as an insulating fastening member.

[0061] <Another embodiment of the joint> In the battery of the present disclosure, the first current collector layer, the insulating sealing member, and the second current collector layer may be stacked in the joint portion in the order of the second current collector layer, the insulating sealing member, and the first current collector layer from the side farthest from the electrolyte layer.

[0062] FIG. 4 is an example of a schematic cross-sectional view showing a cell of the present disclosure, but is not limited to this case.

[0063] A joint formed of the first current collector layer 10, the insulating sealing member 15, and the second current collector layer 14 is provided on the peripheral region 12a of the electrolyte layer 12. In FIG. 5, the second current collector layer 14, the insulating sealing member 15, and the first current collector layer 10 are stacked in this order from the side farthest from the electrolyte layer 12. The first current collector layer 10 closest 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 another member such as an insulating fastening member.

[0064] <Method for manufacturing a single cell> The method for manufacturing a cell according to the present disclosure is a method for manufacturing a 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, a laminate including 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 unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region, and the first electrode active material layer is laminated only on the inner region; folding the second current collector layer so as to enclose the electrolyte layer and the second electrode active material layer, and joining the second current collector layer to the first current collector layer on the peripheral region via an insulating sealing member 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; Includes.

[0065] According to the method for manufacturing a cell of the present disclosure, it is possible to provide a cell that has improved energy density per unit area and energy density per unit volume. For details of the cell manufactured by the method for manufacturing a cell of the present disclosure, please refer to the description of the cell of the present disclosure. [Example]

[0066] 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.

[0067] Example 1: Fabrication of a single cell LiNi as a positive electrode active material 1 / 3 Co 1 / 3 Mn 1 / 3 A positive electrode composite containing LiI-LiBr-Li2S-P2S5 as a solid electrolyte, VGCF (vapor grown carbon fiber) as a conductive additive, and SBR (styrene butadiene rubber) as a binder was prepared, and a positive electrode active material layer, which is a first electrode active material layer, was obtained from this positive electrode composite.

[0068] In addition, a negative electrode composite containing graphite as a negative electrode active material, LiI-LiBr-Li2S-P2S5 as a solid electrolyte, and SBR as a binder was prepared, and a negative electrode active material layer, which is a second electrode active material layer, was obtained from this negative electrode composite.

[0069] Furthermore, a solid electrolyte mixture containing LiI-LiBr-Li2S-P2S5 as a solid electrolyte and SBR as a binder was prepared, and a solid electrolyte layer was obtained from this solid electrolyte mixture.

[0070] 5(A), a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer were laminated to obtain an electrode laminate. The negative electrode active material layer and the solid electrolyte layer each had a peripheral region and an inner region located inside the peripheral region, and the positive electrode active material layer was laminated only on the inner region of the solid electrolyte layer.

[0071] The electrode laminate was placed on the nickel foil, which served as the second current collector layer, so that the negative electrode active material layer was in contact with the nickel foil. As shown in Figure 5(B), a PP (polypropylene) film, which served as an insulating fastening member, was used to cover the area from the peripheral region of the solid electrolyte layer to the nickel foil. The entire assembly was then heated (150°C, 1 minute) to temporarily fix the electrode laminate on the nickel foil.

[0072] As shown in Figure 5(C), the nickel foil was bent along the PP film, which served as an insulating fastening member. Next, as shown in Figure 5(D), a PP film, which served as an insulating sealing member, was placed on top of the bent nickel foil in the peripheral region. An aluminum foil, which served as a first current collector layer, was then placed on top of the PP film, so as to be in contact with the PP film and the positive electrode active material layer placed in the peripheral region.

[0073] The entire assembly was then heated (160°C for 1 minute), causing the nickel foil to form a bond with the aluminum foil on the peripheral region, thereby sealing the positive electrode active material layer, solid electrolyte layer, and negative electrode active material layer, and obtaining a single cell in which an outer casing was formed by the first current collector layer and the second current collector layer. Here, the width of the bond was 3 mm, and the thickness of the bond was 100% of the total thickness of the first current collector layer and the first electrode active material layer.

[0074] While preferred embodiments of the cells of the present disclosure have been described, those skilled in the art will recognize that modifications may be made without departing from the scope of the claims. [Explanation of symbols]

[0075] 10 First current collector layer 11 First electrode active material layer 12 Electrolyte layer 12a Peripheral Area 12b Inner area 13 Second electrode active material layer 14 Second current collector layer 15 Insulating sealing material 16 Thickness of joint 17 Total thickness of the first current collector layer and the first electrode active material layer 20 Aluminum foil 21 Cathode active material layer 22 Solid electrolyte layer 23 Negative electrode active material layer 24 Nickel foil 25 PP film (insulating sealing material) 26 PP film (insulating fastening material)

Claims

1. A single battery 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, When viewed from a stacking direction of the layers constituting the unit cell, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region that is located more inward than the peripheral region, the first electrode active material layer is deposited only on the inner region; the second current collector layer is folded so as to enclose the electrolyte layer and the second electrode active material layer, and is joined to the first current collector layer on the peripheral region via an insulating sealing member to form a joint, whereby 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. AA battery.

2. 2. The battery according to claim 1, wherein a thickness of the joint between the first current collector layer, the insulating sealing member, and the second current collector layer in the stacking direction is equal to or smaller than a total thickness of the first current collector layer and the first electrode active material layer.

3. 2. The battery according to claim 1, wherein, at the joint, 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: the first current collector layer, the insulating sealing member, and the second current collector layer.

4. 2. The battery according to claim 1, wherein, at the joint, the first current collector layer, the insulating sealing member, and the second current collector layer are stacked in the following order from a side farther from the electrolyte layer: the second current collector layer, the insulating sealing member, and the first current collector layer.

5. The battery according to any one of claims 1 to 4, wherein the electrolyte layer is a solid electrolyte layer.

6. A method for producing a single battery, comprising 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 in this order, the method comprising the steps of: a laminate including 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 a stacking direction of the layers constituting the single battery, the electrolyte layer and the second electrode active material layer have a peripheral region and an inner region located inside the peripheral region, and the first electrode active material layer is laminated only on the inner region; folding the second current collector layer so as to enclose the electrolyte layer and the second electrode active material layer, and joining the second current collector layer to the first current collector layer on the peripheral region via an insulating sealing member 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; A method for producing a single battery comprising the steps of:

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