All-solid-state battery and method for manufacturing the same

Abstract

The purpose of the present invention is to provide an all-solid-state battery and a method for manufacturing an all-solid-state battery, both of which enable suppression of damage during in manufacturing steps. Provided is an all-solid-state battery comprising: a positive electrode current collector; a positive electrode active material layer provided on the surface of the positive electrode current collector; a first elastic member that covers the periphery of the positive electrode active material layer and that has an elastic modulus equal to or less than the elastic modulus of the positive electrode active material layer; a solid electrolyte layer opposing the positive electrode current collector with the first elastic member and the positive electrode active material layer interposed therebetween; a negative electrode current collector opposing the positive electrode current collector with the solid electrolyte layer interposed therebetween; and a negative electrode active material layer that is provided between the negative electrode current collector and the solid electrolyte layer and that is disposed inside relative to the periphery of the solid electrolyte layer.

Description

[Technical Field]

[0001] The present invention relates to an all-solid-state battery and a method for manufacturing an all-solid-state battery. [Background technology]

[0002] All-solid-state batteries, such as all-solid-state lithium secondary batteries, are being actively developed. These all-solid-state batteries have, for example, a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer, in this order (see, for example, JP 2020-21551 A). Summary of the Invention

[0003] In such all-solid-state batteries, it is desirable to prevent damage during the manufacturing process, such as cracking of each layer, etc. Therefore, an object of the present invention is to provide an all-solid-state battery that can prevent damage during the manufacturing process and a method for manufacturing an all-solid-state battery.

[0004] An all-solid-state battery according to one embodiment of the present invention includes a positive electrode current collector, a positive electrode active material layer provided on a surface of the positive electrode current collector, a first elastic member covering a periphery of the positive electrode active material layer and having an elastic modulus equal to or lower than that of the positive electrode active material layer, a solid electrolyte layer facing the positive electrode current collector with the first elastic member and the positive electrode active material layer interposed therebetween, an anode current collector facing the positive electrode current collector with the solid electrolyte layer interposed therebetween, and an anode active material layer provided between the anode current collector and the solid electrolyte layer and positioned inside the periphery of the solid electrolyte layer. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the configuration of an all-solid-state battery according to one embodiment of the present invention. [Figure 2] 2 is a diagram showing a planar configuration of a positive electrode active material layer and a first elastic member shown in FIG. 1. FIG. [Figure 3] FIG. 2 is a cross-sectional view showing a part of the all-solid-state battery shown in FIG. [Figure 4]FIG. 4 is a cross-sectional view showing another example of the all-solid-state battery shown in FIG. [Figure 5] FIG. 4 is a cross-sectional view showing another example of the all-solid-state battery shown in FIG. 3. [Figure 6] FIG. 4 is a cross-sectional view showing another example of the all-solid-state battery shown in FIG. 3. [Figure 7] 6(A) is an enlarged view of a portion of the solid electrolyte layer and the first elastic member shown in FIG. 4, and FIG. 6(B) is an enlarged view of a portion of the solid electrolyte layer and the first elastic member shown in FIG. 6. [Figure 8] 2 is a diagram showing the planar configuration of the negative electrode active material layer and the second elastic member shown in FIG. 1. FIG. [Figure 9] FIG. 4 is a cross-sectional view showing another example of the all-solid-state battery shown in FIG. [Figure 10] FIG. 4 is a cross-sectional view showing another example of the all-solid-state battery shown in FIG. [Figure 11] 2(A) to 2(C) are cross-sectional views sequentially showing the steps of the method for producing the all-solid-state battery shown in FIG. [Figure 12] FIG. 11(B) is a cross-sectional view showing a step subsequent to the step shown in FIG. [Figure 13] FIG. 11(B) is a cross-sectional view showing another example of the step shown in FIG. 11(C). [Figure 14] 13 is a cross-sectional view showing another example of the step shown in FIG. 12. [Figure 15] 1A is a cross-sectional view showing the configuration of an all-solid-state battery at an SOC (State of Charge) of 0% and FIG. 1B is a cross-sectional view showing the configuration of an all-solid-state battery at an SOC of 100%. [Figure 16] 10A to 10C are cross-sectional views showing a method for manufacturing an all-solid-state battery according to a comparative example. [Figure 17] FIG. 10 is a cross-sectional view showing the configuration of a main part of an all-solid-state battery according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0006] An all-solid-state battery according to one embodiment of the present invention includes a positive electrode current collector, a positive electrode active material layer provided on the surface of the positive electrode current collector, a first elastic member covering the periphery of the positive electrode active material layer and having an elastic modulus equal to or lower than that of the positive electrode active material layer, a solid electrolyte layer facing the positive electrode current collector with the first elastic member and the positive electrode active material layer interposed therebetween, a negative electrode current collector facing the positive electrode current collector with the solid electrolyte layer interposed therebetween, and a negative electrode active material layer provided between the negative electrode current collector and the solid electrolyte layer and positioned inward from the periphery of the solid electrolyte layer. According to the present invention, a first elastic member is provided covering the periphery of the positive electrode active material layer, and a solid electrolyte layer is provided facing the positive electrode current collector with the first elastic member and the positive electrode active material layer interposed therebetween. This reduces the application of localized force to the solid electrolyte layer even when the solid electrolyte layer is pressed during manufacturing, thereby reducing the occurrence of cracks in the solid electrolyte layer. This makes it possible to reduce damage during the manufacturing process.

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments. Note that the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios. Hereinafter, when it is described that the thickness or elastic modulus of each part is the same (equal), it is sufficient that these are substantially the same, and manufacturing errors (for example, about ±5%) are included.

[0008] <Embodiment> [Structure of all-solid-state batteries] FIG. 1 shows an example of the configuration of an all-solid-state battery 100 according to one embodiment of the present invention. The all-solid-state battery 100 is, for example, an all-solid-state lithium secondary battery that can be charged and discharged multiple times. The all-solid-state battery 100 includes, for example, a power generation element 1, a positive electrode current collector 2, a negative electrode current collector 3, a first elastic member 41, and a second elastic member 42. The positive electrode current collectors 2 and the negative electrode current collectors 3 are alternately stacked, and the power generation element 1 is disposed between the positive electrode current collectors 2 and the negative electrode current collectors 3. In the all-solid-state battery 100, for example, a plurality of positive electrode current collectors 2 are connected in parallel with each other, and a plurality of negative electrode current collectors 3 are connected in parallel with each other. In the following description, the stacking direction of the positive electrode current collectors 2 and the negative electrode current collectors 3 may be referred to as the Z direction, and the directions parallel to the main surfaces of the positive electrode current collectors 2 and the negative electrode current collectors 3 may be referred to as the X direction and the Y direction, respectively.

[0009] In the all-solid-state battery 100, for example, a laminated structure of a power generating element 1, a positive electrode current collector 2, and a negative electrode current collector 3 is sealed in a battery exterior material (not shown) such as a laminate film, and further sandwiched between two metal plates. This laminated structure is pressurized (constrained) in the stacking direction (Z direction). The lower limit of the constraining pressure applied to the power generating element 1 in the stacking direction is, for example, 0.1 MPa or more, preferably 1 MPa or more, more preferably 3 MPa or more, and even more preferably 5 MPa or more. The upper limit of the constraining pressure applied to the power generating element 1 in the stacking direction is, for example, 100 MPa or less, preferably 70 MPa or less, more preferably 40 MPa or less, and even more preferably 10 MPa or less.

[0010] The power generating element 1 includes, for example, a positive electrode active material layer 11, a solid electrolyte layer 12, and a negative electrode active material layer 13, and in the all-solid-state battery 100, these are stacked in this order from the positive electrode current collector 2 side: the positive electrode active material layer 11, the solid electrolyte layer 12, and the negative electrode active material layer 13. The periphery (periphery in the XY plane) of the power generating element 1 is located inside the peripheries of the positive electrode current collector 2 and the negative electrode current collector 3. The planar shape (XY plane) of each of the positive electrode active material layer 11, the solid electrolyte layer 12, and the negative electrode active material layer 13 is, for example, a quadrangle such as a rectangle, a circle, or an ellipse. A first insulating elastic member 41 is provided between the positive electrode current collector 2 and the solid electrolyte layer 12, together with the positive electrode active material layer 11, and a second insulating elastic member 42 is provided between the negative electrode current collector 3 and the solid electrolyte layer 12, together with the negative electrode active material layer 13.

[0011] The positive electrode current collector 2 and the negative electrode current collector 3 are conductive members that function as electron flow paths during battery reactions (charge / discharge reactions), and have, for example, a thin plate (foil) shape. The negative electrode current collector 3 faces the positive electrode current collector 2 with the power generation element 1 (solid electrolyte layer 12) in between. There are no particular restrictions on the materials that make up the positive electrode current collector 2 and the negative electrode current collector 3. For example, metals or conductive resins can be used as materials for the positive electrode current collector 2 and the negative electrode current collector 3.

[0012] Examples of metals include aluminum (Al), nickel (Ni), iron (Fe), stainless steel (SUS), titanium (Ti), and copper (Cu). Other examples include clad materials of nickel and aluminum, and clad materials of copper and aluminum. A foil in which a metal surface is coated with aluminum may also be used. Among these, aluminum, stainless steel, copper, and nickel are preferred from the viewpoints of electronic conductivity and battery operating potential. Examples of conductive resins include resins in which a conductive filler is added to a non-conductive polymer material. There are no particular limitations on the thickness of the positive electrode current collector 2 and the negative electrode current collector 3, but an example is 10 to 100 μm.

[0013] The positive electrode current collector 2 and the negative electrode current collector 3 may have a single-layer structure made of a single material, or may have a laminate structure made of an appropriate combination of layers made of these materials. From the viewpoint of weight reduction, the positive electrode current collector 2 and the negative electrode current collector 3 preferably include at least a conductive resin layer made of a resin having conductivity. Furthermore, from the viewpoint of blocking the movement of lithium ions between the layers of the unit cell, a metal layer may be provided on a portion of the positive electrode current collector 2 and the negative electrode current collector 3.

[0014] The planar (XY plane) shape of the positive electrode current collector 2 and the negative electrode current collector 3 is, for example, a quadrangle such as a rectangle, a circle, an ellipse, etc. The sizes of the positive electrode current collector 2 and the negative electrode current collector 3 in the XY plane are, for example, approximately the same.

[0015] The positive electrode active material layers 11 are provided on the surface of the positive electrode current collector 2, more specifically, on the main surfaces of the positive electrode current collector 2. The positive electrode active material layers 11 are provided, for example, on one and the other main surfaces of the positive electrode current collector 2, and the positive electrode current collector 2 is disposed between the pair of positive electrode active material layers 11.

[0016] The positive electrode active material layer 11 is preferably formed using, for example, NMC811 (lithium nickel cobalt manganese oxide) as a main raw material. The positive electrode active material layer 11 also preferably contains a positive electrode active material containing sulfur. The type of sulfur-containing positive electrode active material is not particularly limited, but examples include elemental sulfur (S) as well as particles or thin films of organic sulfur compounds or inorganic sulfur compounds. Any material can be used as long as it is capable of releasing lithium ions during charging and absorbing lithium ions during discharging by utilizing the oxidation-reduction reaction of sulfur.

[0017] The thickness (size in the Z direction) of the positive electrode active material layer 11 varies depending on the configuration of the intended lithium secondary battery, but is preferably within a range of 0.1 to 1000 μm, and more preferably 40 to 100 μm. The thickness of the positive electrode active material layer 11 is preferably greater than the thickness of the negative electrode active material layer 13 at an SOC of 100%.

[0018] The modulus of elasticity of the positive electrode active material layer 11, specifically the compressive modulus of elasticity of the positive electrode active material layer 11, is, for example, 0.1 GPa to 100 GPa, and preferably 3 GPa to 20 GPa. The compressive modulus can be determined, for example, as follows. First, a test piece with a diameter of 2 mm is used, and the thickness deformation is measured in a uniaxial compression test using a universal testing machine. Then, the compressive strain is calculated based on the thickness deformation and the initial thickness. Next, a stress-strain diagram is created using the compressive stress measured simultaneously with the thickness deformation. The compressive modulus can be determined from the slope of this stress-strain diagram.

[0019] The solid electrolyte layer 12 is provided so as to extend from the positive electrode active material layer 11 and the negative electrode active material layer 13. In other words, the size of the solid electrolyte layer 12 in the XY plane is larger than the size of the positive electrode active material layer 11 and the negative electrode active material layer 13 in the XY plane. By extending the solid electrolyte layer 12 from the positive electrode active material layer 11 and the negative electrode active material layer 13, it is possible to prevent short circuits from occurring at the ends of the positive electrode active material layer 11 and the negative electrode active material layer 13. It is preferable that the solid electrolyte layer 12 extend from the positive electrode active material layer 11 and the negative electrode active material layer 13 all around.

[0020] The positive electrode active material layer 11 and the first elastic member 41 are provided between the solid electrolyte layer 12 and the positive electrode current collector 2. In other words, the solid electrolyte layer 12 faces the positive electrode current collector 2 with the first elastic member 41 and the positive electrode active material layer 11 interposed therebetween.

[0021] The negative electrode active material layer 13 and the second elastic member 42 are provided between the solid electrolyte layer 12 and the negative electrode current collector 3. In other words, the solid electrolyte layer 12 faces the negative electrode current collector 3 with the second elastic member 42 and the negative electrode active material layer 13 interposed therebetween.

[0022] The solid electrolyte layer 12 interposed between the positive electrode active material layer 11 and the negative electrode active material layer 13 contains a solid electrolyte as a main component. Examples of this solid electrolyte include sulfide solid electrolytes and oxide solid electrolytes, with sulfide solid electrolytes being preferred. Examples of sulfide solid electrolytes include LPS-based (e.g., argyrodite (Li6PS5Cl)), LGPS-based (e.g., Li 10 GeP2S 12 ) materials are included.

[0023] The thickness of solid electrolyte layer 12 varies depending on the desired configuration of the lithium secondary battery, but is preferably within the range of 0.1 to 1000 μm, and more preferably 10 to 40 μm, for example.

[0024] The negative electrode active material layer 13 is provided on the surface of the negative electrode current collector 3, more specifically, on the main surface of the negative electrode current collector 3. The negative electrode active material layer 13 is provided, for example, on one main surface and the other main surface of the negative electrode current collector 3, and the negative electrode current collector 3 is disposed between the pair of negative electrode active material layers 13. The negative electrode active material layer 13 provided between the negative electrode current collector 3 and the solid electrolyte layer 12 is disposed inside the periphery of the solid electrolyte layer 12 (the periphery in the XY plane).

[0025] The negative electrode active material layer 13 is made of a material having electrical conductivity and / or lithium ion conductivity. The negative electrode active material layer 13 is made of, for example, a lithium alloy or a negative electrode active material containing lithium metal. The negative electrode active material layer 13 is preferably made of lithium metal. The negative electrode active material layer 13 may be made of stainless steel (SUS), copper (Cu), carbon black (fine carbon particles), or the like. The thickness of the negative electrode active material layer 13 is, for example, in the range of 0.1 to 1000 μm. The compressive elastic modulus of the negative electrode active material layer 13 is, for example, 0.1 GPa to 100 GPa, and preferably 3 GPa to 20 GPa. When the all-solid-state battery 100 is charged, a lithium metal layer (metal layer 14 in FIG. 15(B) described later) is deposited between the negative electrode current collector 3 and the solid electrolyte layer 12. When the negative electrode active material layer 13 in a state of 100% SOC contains an alkali metal such as lithium as a main component, the battery capacity of the all-solid-state battery 100 can be ensured.

[0026] An insulating first elastic member 41 provided between the positive electrode current collector 2 and the solid electrolyte layer 12 covers the periphery of the positive electrode active material layer 11. That is, the first elastic member 41 is provided in the same layer as the positive electrode active material layer 11. Although details will be described later, by providing such a first elastic member 41, even if the solid electrolyte layer 12 is pressed during manufacturing, localized force is less likely to be applied to the solid electrolyte layer 12, and cracks, etc., of the solid electrolyte layer 12 during manufacturing can be suppressed.

[0027] 2 shows an example of the planar (XY plane) shapes of the first elastic member 41 and the positive electrode active material layer 11. The first elastic member 41 covers the periphery of the positive electrode active material layer 11 over the entire periphery of the positive electrode active material layer 11. The first elastic member 41 is provided around the positive electrode active material layer 11 in the shape of a frame, for example.

[0028] FIG. 3 shows a portion of the all-solid-state battery 100 shown in FIG. 1. The thickness (natural length) of the first elastic member 41, which is provided in the same layer as the positive electrode active material layer 11, is preferably, for example, within a range of 0.1 to 1000 μm, more preferably 40 to 100 μm. The thickness of the first elastic member 41 is preferably approximately the same as the thickness of the positive electrode active material layer 11 when the SOC (State of Charge) is 0%, and is preferably, for example, 0.9 to 1.0 times the thickness of the positive electrode active material layer 11. This more effectively prevents damage to the solid electrolyte layer 12 during manufacturing. The thickness of the first elastic member 41 may be greater than the thickness of the positive electrode active material layer 11, provided that the effect of the first elastic member 41 is not impaired. For example, the thickness of the first elastic member 41 may be 1.1 times or less the thickness of the positive electrode active material layer 11 when the SOC is 0%.

[0029] The first elastic member 41 is provided, for example, from the peripheral edge of the positive electrode active material layer 11 to a position overlapping the peripheral edge of the solid electrolyte layer 12, and the peripheral edge of the first elastic member 41 is disposed in the same position as the peripheral edge of the solid electrolyte layer 12 when viewed in a planar view (XY plane).

[0030] 4 shows another example of the first elastic member 41. The first elastic member 41 may be provided so as to extend beyond the solid electrolyte layer 12, or the periphery of the first elastic member 41 may be disposed outside the periphery of the solid electrolyte layer 12 in a planar (XY) view. By providing the first elastic member 41 in this manner from the periphery of the positive electrode active material layer 11 to a position overlapping at least the periphery of the solid electrolyte layer 12, damage to the solid electrolyte layer 12 during manufacturing can be more effectively prevented.

[0031] The first elastic member 41 is preferably disposed inside the positive electrode current collector 2 and the negative electrode current collector 3 in a plan view (XY plane). By providing the first elastic member 41 inside the positive electrode current collector 2 and the negative electrode current collector 3, even if a volume change occurs in the all-solid-state battery 100 due to charging and discharging, the first elastic member 41 is less susceptible to this effect. This makes it possible to suppress deterioration of the first elastic member 41 and suppress a decrease in the reliability of the all-solid-state battery 100.

[0032] 5 and 6 show other examples of the first elastic member 41. The first elastic member 41 extending from the solid electrolyte layer 12 may cover the entire end face of the solid electrolyte layer 12 (FIG. 5) or a part of the end face (FIG. 6).

[0033] 7(A) and 7(B) show enlarged views of the vicinity of an end face of the solid electrolyte layer 12. FIG. 7(A) shows an end face of the solid electrolyte layer 12 (e.g., FIG. 4) that is not covered with the first elastic member 41, and FIG. 7(B) shows an end face of the solid electrolyte layer 12 (e.g., FIG. 6) that is covered with the first elastic member 41. Covering the end face of the solid electrolyte layer 12 with the first elastic member 41 increases the contact area between the solid electrolyte layer 12 and the first elastic member 41, improving adhesion therebetween. Therefore, for example, when the all-solid-state battery 100 is mounted on a vehicle or the like, it is possible to prevent peeling between the solid electrolyte layer 12 and the first elastic member 41 and damage to the solid electrolyte layer 12 due to vibrations, shocks, etc.

[0034] The first elastic member 41 extending from the solid electrolyte layer 12 is preferably disposed between one end (for example, the lower end) and the other end (for example, the upper end) in the thickness direction (Z direction) of the solid electrolyte layer 12, and is preferably disposed at a position not exceeding the other end of the solid electrolyte layer 12. By providing the first elastic member 41 at a position not exceeding the other end in the thickness direction of the solid electrolyte layer 12, a decrease in battery performance caused by the first elastic member 41 is suppressed.

[0035] The first elastic member 41 has an elastic modulus equal to or less than that of the positive electrode active material layer 11. As a result, when a constraining pressure is applied in the stacking direction of the power generation element section 1 during operation of the all-solid-state battery 100, the first elastic member 41 deforms to the same extent as the positive electrode active material layer 11. Therefore, a predetermined constraining pressure is applied to the positive electrode active material layer 11, and the all-solid-state battery 100 exhibits desired battery performance. The first elastic member 41 deforms in accordance with the volume change of the positive electrode active material layer 11 when the all-solid-state battery 100 is charged and discharged.

[0036] The elastic modulus of the first elastic member 41, specifically the compressive elastic modulus, is, for example, 0.1 GPa to 100 GPa, and preferably 1 GPa to 10 GPa. The elastic modulus of the first elastic member 41 is preferably the same as the elastic modulus of the positive electrode active material layer 11. This makes it possible to more effectively prevent damage to the solid electrolyte layer 12 during production.

[0037] The first elastic member 41 is made of, for example, a powder compact of polyimide, polyethylene, or inorganic powder containing a binder. The first elastic member 41 may also be made of aluminum oxide (Al2O3, bulk), zirconia (ZrO2), polyethylene terephthalate (PET), Kapton (registered trademark), epoxy resin, polytetrafluoroethylene (PTFE), rubber (natural rubber, synthetic rubber), or the like.

[0038] An insulating second elastic member 42 provided between the negative electrode current collector 3 and the solid electrolyte layer 12 covers the periphery of the negative electrode active material layer 13. That is, the second elastic member 42 is provided in the same layer as the negative electrode active material layer 13. By providing such a second elastic member 42, cracks and the like in the solid electrolyte layer 12 during manufacturing can be more effectively suppressed.

[0039] 8 shows an example of the planar (XY plane) shapes of the second elastic member 42 and the negative electrode active material layer 13. The second elastic member 42 covers the periphery of the negative electrode active material layer 13 over the entire periphery of the negative electrode active material layer 13. The second elastic member 42 is provided around the negative electrode active material layer 13 in the shape of a frame, for example.

[0040] The thickness of the second elastic member 42 provided in the same layer as the negative electrode active material layer 13 is, for example, within a range of 0.1 to 1000 μm. The thickness (natural length) of the second elastic member 42 is preferably the same as or greater than the thickness of the negative electrode active material layer 13 when the SOC is 0%. This makes it possible to more effectively prevent damage to the solid electrolyte layer 12 during production.

[0041] The second elastic member 42 is provided, for example, from the peripheral edge of the negative electrode active material layer 13 to a position overlapping the peripheral edge of the solid electrolyte layer 12, and the peripheral edge of the second elastic member 42 is located at the same position as the peripheral edge of the solid electrolyte layer 12 in a planar (XY) view ( FIG. 3 ). Alternatively, the second elastic member 42 may be provided extending beyond the solid electrolyte layer 12, and the peripheral edge of the second elastic member 42 may be located outside the peripheral edge of the solid electrolyte layer 12 in a planar (XY) view. The position of the peripheral edge of the first elastic member 41 and the position of the peripheral edge of the second elastic member 42 may be different. By providing the second elastic member 42 from the peripheral edge of the negative electrode active material layer 13 to a position overlapping at least the peripheral edge of the solid electrolyte layer 12, damage to the solid electrolyte layer 12 during manufacturing can be more effectively prevented.

[0042] The second elastic member 42 is preferably disposed inside the positive electrode current collector 2 and the negative electrode current collector 3 in a plan view (XY plane). By providing the second elastic member 42 inside the positive electrode current collector 2 and the negative electrode current collector 3, even if a volume change occurs in the all-solid-state battery 100 due to charging and discharging, the second elastic member 42 is less susceptible to this effect. This makes it possible to suppress deterioration of the second elastic member 42 and suppress a decrease in the reliability of the all-solid-state battery 100.

[0043] 9 and 10 show other examples of the second elastic member 42. The second elastic member 42 extending from the solid electrolyte layer 12 may cover all (FIG. 9) or part (FIG. 10) of the end face of the solid electrolyte layer 12. Part of the end face of the solid electrolyte layer 12 may be covered by the first elastic member 41, and the remainder may be covered by the second elastic member 42 (FIG. 10).

[0044] The second elastic member 42 preferably has an elastic modulus equal to or less than that of the negative electrode active material layer 13, and more preferably has an elastic modulus equal to that of the negative electrode active material layer 13. This makes it possible to more effectively prevent damage to the solid electrolyte layer 12 during production.

[0045] Furthermore, it is preferable that the second elastic member 42 has a smaller elastic modulus than the first elastic member 41. In the all-solid-state battery 100, the volume of the negative electrode active material layer 13 changes more greatly than the positive electrode active material layer 11 during charging and discharging. For this reason, by providing the second elastic member 42, which has a smaller elastic modulus, on the periphery of the negative electrode active material layer 13, the first elastic member 41 and the second elastic member 42 can more easily follow and deform during charging and discharging of the all-solid-state battery 100. The second elastic member 42 deforms in accordance with the change in volume of the negative electrode active material layer 13 during charging and discharging of the all-solid-state battery 100.

[0046] The modulus of elasticity of the second elastic member 42, specifically the compressive modulus of elasticity, is, for example, 0.1 GPa to 100 GPa, and preferably 1 GPa to 10 GPa.

[0047] The second elastic member 42 is made of, for example, polyimide, polyethylene, or ethylene propylene diene rubber (EPDM). The second elastic member 42 may be made of aluminum oxide, zirconia, polyethylene terephthalate (PET), Kapton (registered trademark), epoxy resin, polytetrafluoroethylene (PTFE), or rubber (natural rubber, synthetic rubber). The second elastic member 42 preferably has rubber elasticity and preferably contains a rubber material. This more effectively prevents damage to the solid electrolyte layer 12 during manufacturing.

[0048] [Manufacturing method for all-solid-state batteries] 11(A) to 11(C) and 12 show the steps of the method for manufacturing the all-solid-state battery 100 in order.

[0049] First, after forming the positive electrode current collector 2, a positive electrode active material layer 11 and a first elastic member 41 are formed on the surface (main surface) of the positive electrode current collector 2 (FIG. 11(A)). The first elastic member 41 is formed, for example, by using a mask after the positive electrode active material layer 11 is formed on the positive electrode current collector 2. The first elastic member 41 is formed, for example, by applying a resin material to the surface of the positive electrode current collector 2. The first elastic member 41 may be formed using a transfer method, or the first elastic member 41 may be fixed onto the positive electrode current collector 2 using an adhesive layer. The positive electrode active material layer 11 and the first elastic member 41 may be formed on one main surface and the other main surface of the positive electrode current collector 2 (see FIG. 13 described later).

[0050] After forming the positive electrode active material layer 11 and the first elastic member 41 on the surface of the positive electrode current collector 2, the solid electrolyte layer 12 is formed on the positive electrode active material layer 11 and the first elastic member 41 (FIG. 11(B)). The solid electrolyte layer 12 is formed by applying a solid electrolyte onto the positive electrode active material layer 11 and the first elastic member 41 using, for example, a die coater. The solid electrolyte layer 12 may also be formed using a transfer method.

[0051] After the solid electrolyte layer 12 is formed, the solid electrolyte layer 12 is pressed using a roll press 50 ( FIG. 11(C) ) to adhere the solid electrolyte layer 12 to the cathode active material layer 11. The adherence between the solid electrolyte layer 12 and the cathode active material layer 11 reduces the contact resistance between the solid electrolyte layer 12 and the cathode active material layer 11, improving the battery performance of the all-solid-state battery 100. Here, because the first elastic member 41 is formed around the periphery of the cathode active material layer 11, localized force is less likely to be applied to the solid electrolyte layer 12 when the solid electrolyte layer 12 is pressed using the roll press 50. This reduces bending stress on the solid electrolyte layer 12, thereby preventing damage to the solid electrolyte layer 12 during manufacturing. Instead of using the roll press 50, an isostatic press may be used to adhere the solid electrolyte layer 12 to the cathode active material layer 11.

[0052] Fig. 13 shows another example of the step shown in Fig. 11(C). The solid electrolyte layers 12 formed on one and the other principal surfaces of the positive electrode current collector 2 may be pressed using a roll press 50 or an isostatic press.

[0053] After the solid electrolyte layer 12 is adhered to the positive electrode active material layer 11, the negative electrode active material layer 13 and the negative electrode current collector 3 are assembled thereto ( FIG. 12 ). Specifically, the negative electrode active material layer 13 and the second elastic member 42 are formed on the surface of the negative electrode current collector 3, and then the negative electrode active material layer 13 is adhered to the solid electrolyte layer 12. For example, the positive electrode current collector 2, the positive electrode active material layer 11, the solid electrolyte layer 12, the negative electrode active material layer 13, and the negative electrode current collector 3 are pressed in the stacking direction to adhere the negative electrode active material layer 13 to the solid electrolyte layer 12. Here, because the second elastic member 42 is formed around the periphery of the negative electrode active material layer 13, localized force is less likely to be applied to the solid electrolyte layer 12 during assembly. In other words, bending stress on the solid electrolyte layer 12 is alleviated, and damage to the solid electrolyte layer 12 during manufacturing can be suppressed.

[0054] Fig. 14 shows another example of the step shown in Fig. 12. The negative electrode active material layer 13 and the negative electrode current collector 3 may be assembled on one main surface side and the other main surface side of the positive electrode current collector 2.

[0055] [Operation of all-solid-state batteries] 15(A) and 15(B) show exemplary configurations of the all-solid-state battery 100 at SOC 0% and SOC 100% (fully charged state), respectively. The all-solid-state battery 100 operates, for example, in a state in which a predetermined confining pressure is applied in the stacking direction of the power generating element 1. When the all-solid-state battery 100 is charged, a metal layer 14 is formed between the negative electrode current collector 3 and the solid electrolyte layer 12, more specifically, between the negative electrode current collector 3 and the negative electrode active material layer 13 (FIG. 15(B)). This metal layer 14 is formed when lithium (Li) ions in the positive electrode active material layer 11 pass through the solid electrolyte layer 12 and precipitate as lithium metal (LiM) on the surface of the negative electrode current collector 3, and functions as the negative electrode active material layer 13. That is, in a charged all-solid-state battery 100, the negative electrode active material layer 13 includes the metal layer 14. On the other hand, when the all-solid-state battery 100 is discharged, lithium ions pass from the negative electrode active material layer 13 through the solid electrolyte layer 12 and are absorbed into the positive electrode active material layer 11. When the SOC is 0%, the metal layer 14 disappears (FIG. 15(A)).

[0056] [Actions and effects of all-solid-state batteries] In the all-solid-state battery 100 according to this embodiment, a first elastic member 41 is provided to cover the periphery of the positive electrode active material layer 11, and a solid electrolyte layer 12 is provided to face the positive electrode current collector 2 with the first elastic member 41 and the positive electrode active material layer 11 in between. This makes it difficult for localized force to be applied to the solid electrolyte layer 12 even when the solid electrolyte layer 12 is pressed during manufacturing, thereby suppressing the occurrence of cracks and the like in the solid electrolyte layer 12. The effect of this will be described in detail below.

[0057] FIG. 16 shows a step in a method for manufacturing an all-solid-state battery according to a comparative example, which corresponds to the step in FIG. 11(C) described above. In this method for manufacturing an all-solid-state battery, a first elastic member (for example, first elastic member 41 in FIG. 11(C)) is not formed on the periphery of the positive electrode active material layer 11. In this method for manufacturing an all-solid-state battery, if the solid electrolyte layer 12 is formed wider than the positive electrode active material layer 11, a force is locally applied to the solid electrolyte layer 12 near the periphery of the positive electrode active material layer 11 when pressed by the roll press 50, generating bending stress. This bending stress generated in the solid electrolyte layer 12 may cause cracks in the solid electrolyte layer 12.

[0058] In contrast, in the all-solid-state battery 100, the first elastic member 41 is formed around the periphery of the positive electrode active material layer 11, and then the solid electrolyte layer 12 is formed on the positive electrode active material layer 11 and the first elastic member 41. As a result, the portion of the solid electrolyte layer 12 that widens from the positive electrode active material layer 11 is supported by the first elastic member 41, and therefore, even when pressed by the roll press 50, the bending stress applied to the solid electrolyte layer 12 is alleviated.

[0059] Furthermore, since the first elastic member 41 is provided from the peripheral edge of the positive electrode active material layer 11 to a position overlapping at least the peripheral edge of the solid electrolyte layer 12, the entire portion of the solid electrolyte layer 12 that extends beyond the positive electrode active material layer 11 is supported by the first elastic member 41. Therefore, the bending stress acting on the solid electrolyte layer 12 is more effectively alleviated.

[0060] Furthermore, since the first elastic member 41 has the same elastic modulus as the positive electrode active material layer 11 and also has approximately the same thickness as the positive electrode active material layer 11, the bending stress acting on the solid electrolyte layer 12 is more effectively alleviated.

[0061] Furthermore, in the all-solid-state battery 100, the second elastic member 42 is formed on the periphery of the negative electrode active material layer 13, so that when the positive electrode side and the negative electrode side are assembled via the solid electrolyte layer 12, the portion of the solid electrolyte layer 12 that widens from the negative electrode active material layer 13 is protected by the second elastic member 42. Therefore, the bending stress applied to the solid electrolyte layer 12 is also alleviated during this assembly process.

[0062] Furthermore, since the second elastic member 42 is provided from the peripheral edge of the negative electrode active material layer 13 to a position overlapping at least the peripheral edge of the solid electrolyte layer 12, the entire portion of the solid electrolyte layer 12 that extends beyond the negative electrode active material layer 13 is protected by the second elastic member 42. Therefore, the bending stress acting on the solid electrolyte layer 12 is more effectively alleviated.

[0063] In addition, since the second elastic member 42 has the same elastic modulus as the negative electrode active material layer 13, the bending stress applied to the solid electrolyte layer 12 is more effectively alleviated.

[0064] As described above, in the all-solid-state battery 100 of this embodiment, the first elastic member 41 covering the periphery of the positive electrode active material layer 11 is provided, and the solid electrolyte layer 12 is provided facing the positive electrode current collector 2 with the first elastic member 41 and the positive electrode active material layer 11 in between. This makes it difficult for localized force to be applied to the solid electrolyte layer 12 even when the solid electrolyte layer 12 is pressed during manufacturing, thereby suppressing the occurrence of cracks and the like in the solid electrolyte layer 12. This makes it possible to suppress damage during the manufacturing process.

[0065] Below, a description will be given of modified examples of the all-solid-state battery 100 described in the above embodiment. Note that, in order to avoid duplication of explanation, detailed explanations of the same components as those of the all-solid-state battery described in the above embodiment will be omitted.

[0066] <Modification> 17 shows the configuration of a main part of an all-solid-state battery 100 according to a modified example. The first elastic member 41 of this all-solid-state battery 100 has a tapered shape. Except for this point, the all-solid-state battery 100 according to the modified example has the same configuration as the all-solid-state battery 100 described in the above embodiment, and exhibits the same effects.

[0067] The first elastic member 41 provided between the solid electrolyte layer 12 and the positive electrode current collector 2 gradually becomes larger from the solid electrolyte layer 12 side toward the positive electrode current collector 2 side. In other words, the tapered first elastic member 41 has an outwardly inclined surface from the solid electrolyte layer 12 side toward the positive electrode current collector 2 side.

[0068] The all-solid-state battery 100 is manufactured, for example, as follows. First, a positive electrode current collector 2 is formed, and then a positive electrode active material layer 11 and a tapered first elastic member 41 are formed on the surface of the positive electrode current collector 2 (see FIG. 11(A)). Next, a solid electrolyte layer 12 is formed on the positive electrode active material layer 11 and the first elastic member 41 (see FIG. 11(B)). Thereafter, for example, a roll press 50 is used to press the solid electrolyte layer 12, so that the solid electrolyte layer 12 is brought into close contact with the positive electrode active material layer 11 (see FIG. 11(C)). At this time, by moving the roll press 50 along the inclined surface of the first elastic member 41, stress is less likely to be applied to the end of the solid electrolyte layer 12.

[0069] As in the above embodiment, the all-solid-state battery 100 according to this modification has the first elastic member 41 on the periphery of the positive electrode active material layer 11, and therefore, even if the solid electrolyte layer 12 is pressed during manufacturing, localized force is less likely to be applied to the solid electrolyte layer 12, thereby suppressing the occurrence of cracks or the like in the solid electrolyte layer 12. Furthermore, because the first elastic member 41 has a tapered shape, stress is less likely to be applied to the end of the solid electrolyte layer 12, and damage during the manufacturing process can be more effectively suppressed.

[0070] The all-solid-state battery of the present invention has been described above using embodiments and modifications. However, those skilled in the art can appropriately add, modify, and omit aspects of the present invention within the scope of the technical concept thereof. For example, the configurations, shapes, sizes, etc. of each layer of the all-solid-state battery described in the above embodiments and modifications are merely examples, and other configurations, shapes, sizes, etc. may be used.

[0071] For example, in the above embodiment, a stacked-type (internal parallel connection type) all-solid-state lithium secondary battery has been described as an example, but the present invention is also applicable to other secondary batteries such as bipolar type, etc. Also, in the above embodiment, the all-solid-state battery 100 has been described as having a plurality of power generating element parts 1, positive electrode current collectors 2, and negative electrode current collectors 3, but the all-solid-state battery 100 may have a single-layer structure.

[0072] 2 and 8 show the positive electrode active material layer 11 and the negative electrode active material layer 13 having a rectangular planar shape, the positive electrode active material layer 11 and the negative electrode active material layer 13 may have other planar shapes such as a circle or an ellipse. The planar shape of the all-solid-state battery 100 may be any shape such as a circle, an ellipse, or a rectangle.

[0073] Furthermore, in the above embodiment, an example has been described in which, when the all-solid-state battery 100 is charged, the metal layer 14 containing lithium metal is precipitated in the negative electrode active material layer 13. However, in the all-solid-state battery 100, a metal layer 14 containing an alkali metal such as sodium (Na) or potassium (K) may be precipitated during charging.

[0074] Furthermore, in the above embodiment, an example has been described in which the all-solid-state battery 100 at an SOC of 0% is also provided with the anode active material layer 13, but the all-solid-state battery 100 at an SOC of 0% may not include the anode active material layer 13. In other words, only the metal layer 14 deposited during charging may function as the anode active material layer, and this metal layer 14 may correspond to a specific example of the anode active material layer of the present invention.

[0075] This application is based on Japanese Patent Application No. 2021-163922, filed on October 5, 2021, the disclosure of which is incorporated by reference in its entirety.

[0076] The following embodiments are also included within the scope of the present invention: the all-solid-state battery according to claim 1 having the characteristics of claim 2; the all-solid-state battery according to claim 1 or 2 having the characteristics of claim 3; the all-solid-state battery according to any one of claims 1 to 3 having the characteristics of claim 4; the all-solid-state battery according to any one of claims 1 to 4 having the characteristics of claim 5; the all-solid-state battery according to any one of claims 1 to 5 having the characteristics of claim 6; the all-solid-state battery according to claim 6 having the characteristics of claim 7; the all-solid-state battery according to claim 6 or 7 having the characteristics of claim 8; the all-solid-state battery according to any one of claims 6 to 8 having the characteristics of claim 9; the all-solid-state battery according to any one of claims 1 to 9 having the characteristics of claim 10; the all-solid-state battery according to any one of claims 1 to 10 having the characteristics of claim 11; the all-solid-state battery according to any one of claims 1 to 11 having the characteristics of claim 12; the all-solid-state battery according to claim 12 having the characteristics of claim 13; the all-solid-state battery according to any one of claims 1 to 13 having the characteristics of claim 14; and a method for producing an all-solid-state battery according to any one of claims 1 to 14 having the characteristics of claim 15.

Claims

1. a positive electrode current collector; a positive electrode active material layer provided on a surface of the positive electrode current collector; a first elastic member that covers a periphery of the positive electrode active material layer and has an elastic modulus equal to or lower than that of the positive electrode active material layer; a solid electrolyte layer facing the positive electrode current collector with the first elastic member and the positive electrode active material layer interposed therebetween; an anode current collector facing the cathode current collector with the solid electrolyte layer therebetween; a negative electrode active material layer provided between the negative electrode current collector and the solid electrolyte layer and positioned inside the periphery of the solid electrolyte layer; An all-solid-state battery comprising:

2. The all-solid-state battery according to claim 1 , wherein the elastic modulus of the first elastic member is the same as the elastic modulus of the positive electrode active material layer.

3. The all-solid-state battery according to claim 1 , wherein the first elastic member is provided from a peripheral edge of the positive electrode active material layer to a position overlapping at least the peripheral edge of the solid electrolyte layer.

4. 3. The all-solid-state battery according to claim 1, wherein the thickness of the first elastic member is 0.9 to 1.1 times the thickness of the positive electrode active material layer.

5. The all-solid-state battery according to claim 1 , wherein the first elastic member has a tapered shape that gradually increases from the solid electrolyte layer side toward the positive electrode current collector side.

6. 3. The all-solid-state battery according to claim 1, further comprising a second elastic member provided between the negative electrode current collector and the solid electrolyte layer, covering a periphery of the negative electrode active material layer, and having an elastic modulus smaller than that of the first elastic member.

7. The all-solid-state battery according to claim 6 , wherein the elastic modulus of the second elastic member is equal to or less than the elastic modulus of the negative electrode active material layer.

8. The all-solid-state battery according to claim 6 , wherein the elastic modulus of the second elastic member is the same as the elastic modulus of the negative electrode active material layer.

9. The all-solid-state battery according to claim 6 , wherein the second elastic member includes rubber.

10. 3. The all-solid-state battery according to claim 1, wherein the first elastic member is provided so as to extend from the solid electrolyte layer, and the first elastic member extending from the solid electrolyte layer is disposed between one end and the other end in a thickness direction of the solid electrolyte layer.

11. The all-solid-state battery according to claim 1 , wherein the first elastic member is provided inside a peripheral edge of the positive electrode current collector.

12. The all-solid-state battery according to claim 1 or 2, wherein the negative electrode active material layer contains an alkali metal in a fully charged state.

13. The all-solid-state battery according to claim 12, wherein the alkali metal is lithium.

14. 3. The all-solid-state battery according to claim 1, wherein the thickness of the positive electrode active material layer is greater than the thickness of the negative electrode active material layer in a fully charged state.

15. forming a positive electrode current collector; forming a first elastic member on a surface of the positive electrode current collector, the first elastic member covering the positive electrode active material layer and a periphery of the positive electrode active material layer and having an elastic modulus equal to or lower than an elastic modulus of the positive electrode active material layer; forming a solid electrolyte layer on the first elastic member and the positive electrode active material layer; pressing the solid electrolyte layer to bring the solid electrolyte layer into close contact with the positive electrode active material layer; A method for manufacturing an all-solid-state battery, comprising:

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