Solid-state battery and method for manufacturing a solid-state battery

Abstract

To provide a solid battery capable of suppressing the occurrence of short-circuit.SOLUTION: A solid battery includes an electrode multilayer body 110 in which an intermediate layer 112, a first solid electrolyte layer 113, a positive electrode 114, and a second solid electrolyte layer 115 are sequentially stacked on a negative electrode 111 and a positive electrode tab 114A extends from the positive electrode 114. The second solid electrolyte layer 115 includes a porous base material. The first solid electrolyte layer 113 does not include a porous base material. In a top view of the electrode multilayer body 110, an outer peripheral edge of the first solid electrolyte layer 113 and the second solid electrolyte layer 115 exists on the outside relative to an outer peripheral edge of the positive electrode 114, and the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are bonded in a region not facing the positive electrode 114 or the positive electrode tab 114A.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to a solid-state battery and a method for manufacturing a solid-state battery. [Background technology]

[0002] In recent years, research and development of rechargeable batteries that contribute to energy efficiency have been conducted to ensure that many people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Patent Document 1 describes an all-solid-state battery having a positive electrode piece having a positive electrode active material layer formed on a positive electrode current collector layer, a negative electrode piece having a negative electrode active material layer formed on a negative electrode current collector layer, and a bag-shaped solid electrolyte layer that houses the positive electrode piece. In this battery, the positive electrode piece and the negative electrode piece housed in the bag-shaped solid electrolyte layer are stacked so that they overlap in a plan view, so that the positive electrode active material layer and the negative electrode active material layer are arranged facing each other via the solid electrolyte layer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-181668 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the all-solid-state battery described in Patent Document 1 does not have a partition separating the ends of the positive electrode piece and the negative electrode piece, which are arranged via a bag-shaped solid electrolyte layer, so a short circuit may occur.

[0006] The present invention aims to provide a solid-state battery capable of suppressing the occurrence of short circuits. [Means for solving the problem]

[0007] (1) A solid-state battery comprising an electrode laminate in which an intermediate layer, a first solid electrolyte layer, a positive electrode, and a second solid electrolyte layer are sequentially stacked on a negative electrode, a positive electrode tab extending from the positive electrode, one of the first solid electrolyte layer and the second solid electrolyte layer containing a porous substrate, the other of the first solid electrolyte layer and the second solid electrolyte layer not containing a porous substrate, and when the electrode laminate is viewed from above, the outer peripheral edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer peripheral edge of the positive electrode, and the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the positive electrode and the positive electrode tab.

[0008] (2) The solid battery according to (1), wherein the positive electrode has a positive electrode composite material layer formed on both sides of the positive electrode current collector, and the electrode laminate has the intermediate layer, the first solid electrolyte layer, the positive electrode, the second solid electrolyte layer, the second intermediate layer, and the second negative electrode sequentially laminated on the negative electrode.

[0009] (3) The solid battery according to (1) or (2), wherein an insulating frame is provided on the outer periphery of the positive electrode, and when the electrode stack is viewed from above, the outer edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer edges of the insulating frame, and the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the insulating frame.

[0010] (4) The solid battery according to any one of (1) to (3), wherein the negative electrode has a lithium metal layer.

[0011] (5) The solid battery according to any one of (1) to (4), wherein the intermediate layer comprises a metal that can be alloyed with lithium and amorphous carbon.

[0012] A method for producing the solid battery according to any one of (6) (1) to (5), comprising: a step of sequentially laminating the first solid electrolyte layer, the positive electrode and the second solid electrolyte layer; and a step of applying pressure from the other side of the first solid electrolyte layer and the second solid electrolyte layer to join the first solid electrolyte layer and the second solid electrolyte layer.

[0013] (7) A solid battery comprising an electrode laminate in which a first solid electrolyte layer, an intermediate layer, a negative electrode and a second solid electrolyte layer are sequentially laminated on a positive electrode, wherein a negative electrode tab extends from the negative electrode, one of the first solid electrolyte layer and the second solid electrolyte layer comprises a porous substrate, the other of the first solid electrolyte layer and the second solid electrolyte layer does not comprise a porous substrate, when the electrode laminate is viewed from a top view, outer peripheral edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside outer peripheral edges of the intermediate layer and the negative electrode, and the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the intermediate layer, the negative electrode and the negative electrode tab.

Effects of the Invention

[0014] According to the present invention, a solid battery capable of suppressing the occurrence of short circuits can be provided.

Brief Description of Drawings

[0015] [Figure 1] It is a perspective view showing an example of the solid battery of the present embodiment. [Figure 2] It is an enlarged top view of the solid battery of FIG. 1. [Figure 3] It is an exploded perspective view of the solid battery of FIG. 1. [Figure 4] It is a sectional view along the A-A direction in FIG. 2. [Figure 5] It is a sectional view along the B-B direction in FIG. 2. [Figure 6] It is a sectional view showing a modification of the laminated structure of the electrode laminate.

Mode for Carrying Out the Invention

[0016] Embodiments of the present invention will be described below with reference to the drawings.

[0017] Figures 1-3 show an example of a solid-state battery according to this embodiment.

[0018] The solid-state battery 100 consists of an electrode laminate 110 in which an intermediate layer 112, a first solid electrolyte layer 113, a positive electrode 114, a second solid electrolyte layer 115, and a substrate 116 are sequentially stacked on a negative electrode 111, and the laminate is packaged with a laminate film 120 as a packaging material. In this case, the solid-state battery 100 has a negative electrode tab 111A extending from the negative electrode 111 and a positive electrode tab 114A extending from the positive electrode 114. Furthermore, the direction in which the negative electrode tab 111A extends is opposite to the direction in which the positive electrode tab 114A extends. In addition, the first solid electrolyte layer 113 does not contain a porous substrate, while the second solid electrolyte layer 115 contains a porous substrate. Furthermore, when the electrode stack 110 is viewed from above, the outer edges of the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are located outside the outer edge of the positive electrode 114, and the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are joined in a region that does not face the positive electrode 114 and the positive electrode tab 114A (see Figures 4 and 5). As a result, the ends of the negative electrode 111 and the ends of the positive electrode 114 are separated by the first solid electrolyte layer 113, thereby suppressing the occurrence of short circuits. In addition, misalignment between the positive electrode 114 and the first solid electrolyte layer 113 and detachment of the positive electrode 114 are suppressed.

[0019] Furthermore, if the positive electrode tab 114A is a porous material, the first solid electrolyte layer 113 and the second solid electrolyte layer 115 can be joined even in the region facing the positive electrode tab 114A.

[0020] Furthermore, the solid electrolytes constituting the first solid electrolyte layer 113 and the second solid electrolyte layer 115 may be different, but it is preferable that they be the same considering the bonding properties between the first solid electrolyte layer 113 and the second solid electrolyte layer 115.

[0021] The first solid electrolyte layer 113 is formed, for example, by a transfer method or a coating method.

[0022] The porous substrate constituting the second solid electrolyte layer 115 is not particularly limited as long as it can be filled with a solid electrolyte, but examples include nonwoven fabrics.

[0023] There are no particular limitations on the method for joining the first solid electrolyte layer 113 and the second solid electrolyte layer 115. For example, one method involves sequentially stacking the intermediate layer 112, the first solid electrolyte layer 113, the positive electrode 114, the second solid electrolyte layer 115, and the substrate 116 on the negative electrode 111, and then applying pressure from the side of the first solid electrolyte layer 113, i.e., the side of the negative electrode 111. At this time, if necessary, heating may be used while applying pressure.

[0024] The timing for joining the first solid electrolyte layer 113 and the second solid electrolyte layer 115 may be before packaging the electrode laminate 110 with the laminate film 120, or it may be when packaging the electrode laminate 110 with the laminate film 120.

[0025] The material that makes up the substrate 116 is not particularly limited as long as it is a material with high rigidity, but stainless steel is one example.

[0026] Alternatively, the order in which the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are stacked may be reversed, and pressure may be applied from the side of the first solid electrolyte layer 113, i.e., from the side of the substrate 116.

[0027] Alternatively, the first solid electrolyte layer 113, the positive electrode 114, and the second solid electrolyte layer 115 may be sequentially stacked, and then pressurized from the side of the first solid electrolyte layer 113 to pre-fabricate the first solid electrolyte layer-positive electrode-second solid electrolyte layer stack. In this case, the stacking order of the first solid electrolyte layer 113 and the second solid electrolyte layer 115 in the electrode stack 110 may be reversed.

[0028] The negative electrode 111 has a negative electrode composite layer 411b formed on one side of the negative electrode current collector 411a, and the positive electrode 114 has a positive electrode composite layer 414b formed on one side of the positive electrode current collector 414a. The negative electrode tab 111A is connected to the negative electrode tab lead 130, and the positive electrode tab 114A is connected to the positive electrode tab lead 140. Furthermore, the negative electrode tab lead 130 is bonded to the laminate film 120 by sealant 150, and the positive electrode tab lead 140 is bonded to the laminate film 120 by sealant 160.

[0029] For example, if the solid battery 100 is a lithium metal secondary battery, the intermediate layer 112 has the function of uniformly depositing lithium metal. As a result, the interface between the intermediate layer 112 and the first solid electrolyte layer 113 is stabilized. Here, the lithium metal secondary battery may be an anode-free battery in which the negative electrode composite layer 411b does not exist at the time of the first charge. In this case, after the first charge and discharge, a lithium metal layer is formed as the negative electrode composite layer 411b.

[0030] The intermediate layer 112 is not particularly limited, but includes, for example, a metal that can be alloyed with lithium and amorphous carbon. Examples of amorphous carbon include carbon blacks such as acetylene black, furnace black, and Ketjen black, as well as coke and activated carbon. Amorphous carbon may be easily graphitizable carbon (soft carbon), difficult-to-graphitize carbon (hard carbon), CNTs (carbon nanotubes), fullerenes, or graphene. Examples of metals that can be alloyed with lithium include tin (Sn), silicon (Si), zinc (Zn), magnesium (Mg), gold (Au), platinum (Pt), palladium (Pd), silver (Ag), aluminum (Al), bismuth (Bi), and antimony (Sb). The metal that can be alloyed with lithium may be nanoparticles.

[0031] The intermediate layer 112 is formed, for example, by a transfer method or a coating method.

[0032] The laminate film 120 has, for example, a metal layer formed on the surface of a resin layer. Examples of resins include polyethylene, polyvinyl fluoride, and polyvinylidene chloride, and examples of metals include aluminum.

[0033] An insulating frame may be provided on the outer periphery of the positive electrode 114. This suppresses the occurrence of short circuits. In this case, when the electrode laminate 110 is viewed from above, the outer edges of the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are located outside the outer edges of the positive electrode 114 and the insulating frame, and the first solid electrolyte layer 113 and the second solid electrolyte layer 115 are joined in areas that do not face the positive electrode 114, the positive electrode tab 114A, and the insulating frame.

[0034] The materials used to construct the insulating frame are not particularly limited as long as they have electronic insulating properties, but examples include insulating oxides such as alumina, resins such as polyvinylidene fluoride (PVDF), and rubbers such as styrene-butadiene rubber (SBR).

[0035] The insulating frame may also have ionic conductivity.

[0036] Figure 6 shows a modified example of the laminated structure of the electrode stack.

[0037] The electrode stack 610 is similar to the electrode stack 110, except that it uses a positive electrode 614 instead of a positive electrode 114, and an intermediate layer 112 and a negative electrode 111 are further arranged between the second solid electrolyte layer 115 and the substrate 116. Here, the positive electrode 614 has positive electrode composite layers formed on both sides of the positive electrode current collector.

[0038] The negative electrodes 111 and the intermediate layer 112, which are positioned on both sides of the positive electrode 614, may be the same or different. Furthermore, the positive electrode composite layers formed on both sides of the positive electrode current collector may be the same or different.

[0039] The solid battery of the present embodiment is not particularly limited, and examples thereof include all-solid lithium ion batteries and all-solid lithium metal batteries.

[0040] Note that the solid battery of the present embodiment may include a plurality of electrode laminates.

[0041] Hereinafter, a case where the solid battery of the present embodiment is an all-solid lithium metal battery will be described.

[0042] The positive electrode current collector is not particularly limited, and for example, an aluminum foil can be used.

[0043] The positive electrode mixture layer contains a positive electrode active material, and may further contain a solid electrolyte, a conductive aid, and a binder.

[0044] The positive electrode active material is not particularly limited as long as it can occlude and release lithium ions, and examples thereof include LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O 2、 Li(Ni 6 / 10 Co 2 / 10 Mn 2 / 10 )O 2、 Li(Ni 8 / 10 Co 1 / 10 Mn 1 / 10 )O 2、 Li(Ni 0.8 Co 0.15 Al 0.05 )O 2、 Li(Ni 1 / 6 Co 4 / 6 Mn 1 / 6 )O 2、 Li(Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )O 2、 LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, and sulfur.

[0045] The solid electrolyte constituting the solid electrolyte layer is not particularly limited as long as it is a material capable of conducting lithium ions, but examples include oxide-based electrolytes and sulfide-based electrolytes (for example, argyrodite-type sulfide solid electrolytes).

[0046] The negative electrode composite layer is a lithium metal layer.

[0047] The negative electrode current collector is not particularly limited, but an example is copper foil.

[0048] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the above embodiments may be modified as appropriate within the scope of the spirit of the present invention. For example, the arrangement of the positive electrode and negative electrode in the solid-state battery may be reversed. In this case, the solid-state battery comprises an electrode laminate in which a first solid electrolyte layer, an intermediate layer, a negative electrode, and a second solid electrolyte layer are sequentially stacked, with a negative electrode tab extending from the negative electrode. Here, one of the first solid electrolyte layer and the second solid electrolyte layer includes a porous substrate, and the other of the first solid electrolyte layer and the second solid electrolyte layer does not include a porous substrate. Furthermore, when the electrode laminate is viewed from above, the outer peripheral edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer peripheral edges of the intermediate layer and the negative electrode, and the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the intermediate layer, the negative electrode, and the negative electrode tab. [Explanation of symbols]

[0049] 100 solid state battery 110, 610 electrode stack 111 Negative electrode 111A Negative Electrode Tab 112 Middle layer 113 First solid electrolyte layer 114, 614 positive electrode 114A Positive Tab 115 Second solid electrolyte layer 116 circuit boards 120 Laminating Film 130 Negative Electrode Tab Lead 140 Positive Tab Lead 150, 160 sealant 411a Negative electrode current collector 411b Negative electrode composite layer 414a Positive electrode current collector 414b Positive electrode composite layer

Claims

1. The electrode laminate comprises an intermediate layer, a first solid electrolyte layer, a positive electrode, and a second solid electrolyte layer sequentially stacked on the negative electrode. A positive electrode tab extends from the aforementioned positive electrode, One of the first solid electrolyte layer and the second solid electrolyte layer includes a porous substrate, The other of the first solid electrolyte layer and the second solid electrolyte layer does not contain a porous substrate. When the electrode stack is viewed from above, the outer edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer edge of the positive electrode. A solid-state battery in which the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the positive electrode and the positive electrode tab.

2. The positive electrode has positive electrode composite material layers formed on both sides of the positive electrode current collector. The solid-state battery according to claim 1, wherein the electrode stack comprises the intermediate layer, the first solid electrolyte layer, the positive electrode, the second solid electrolyte layer, the second intermediate layer, and the second negative electrode, stacked sequentially on the negative electrode.

3. An insulating frame is provided on the outer circumference of the positive electrode. When the electrode stack is viewed from above, the outer edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer edges of the insulating frame. The solid battery according to claim 1, wherein the first solid electrolyte layer and the second solid electrolyte layer are joined in a region that does not face the insulating frame.

4. The solid battery according to claim 1, wherein the negative electrode has a lithium metal layer.

5. The solid battery according to claim 1, wherein the intermediate layer comprises a metal that can be alloyed with lithium and amorphous carbon.

6. A method for manufacturing a solid battery according to any one of claims 1 to 5, A step of sequentially stacking the first solid electrolyte layer, the positive electrode, and the second solid electrolyte layer, A method for manufacturing a solid-state battery, comprising the step of applying pressure from the other side of the first solid electrolyte layer and the second solid electrolyte layer to bond the first solid electrolyte layer and the second solid electrolyte layer.

7. The electrode laminate comprises a positive electrode on which a first solid electrolyte layer, an intermediate layer, a negative electrode, and a second solid electrolyte layer are sequentially stacked. A negative electrode tab extends from the aforementioned negative electrode, One of the first solid electrolyte layer and the second solid electrolyte layer includes a porous substrate, The other of the first solid electrolyte layer and the second solid electrolyte layer does not contain a porous substrate. When the electrode stack is viewed from above, the outer edges of the first solid electrolyte layer and the second solid electrolyte layer are located outside the outer edges of the intermediate layer and the negative electrode. A solid-state battery in which the first solid electrolyte layer and the second solid electrolyte layer are joined in regions that do not face the intermediate layer, the negative electrode, and the negative electrode tab.

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