All-solid battery, all-solid battery system and shutdown method

Abstract

To provide an all-solid battery having a shutdown function.SOLUTION: An all-solid battery comprises a solid electrolyte layer, a positive electrode layer and a negative electrode layer. The solid electrolyte layer includes a solid electrolyte, and a Li occlusion expansion material that is expanded when occluding Li. The Li occlusion expansion material is separated from the positive electrode layer and the negative electrode layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an all-solid-state battery and an all-solid-state battery system. [Background technology]

[0002] An all-solid-state battery is a secondary battery in which all components, including the electrolyte layer, are substantially made of solids. In all-solid-state batteries, lithium ions are usually conducted between the positive and negative electrode layers to charge and discharge the battery.

[0003] It is desirable for all-solid-state batteries to stop operating when an abnormality occurs, i.e., to have a shutdown function.

[0004] In non-aqueous electrolyte secondary batteries, rather than all-solid-state batteries, it is known to use a porous separator in order to obtain a shutdown function (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-027024 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in an all-solid-state battery, since the electrolyte is solid, the shutdown function cannot be realized even if a porous separator is used. Therefore, an object of the present invention is to provide an all-solid-state battery having a shutdown function. [Means for solving the problem]

[0007] In one embodiment, the all-solid-state battery according to the present invention includes a solid electrolyte layer, and a positive electrode layer and a negative electrode layer arranged to sandwich the solid electrolyte layer in a stacking direction. The solid electrolyte layer includes a solid electrolyte and a Li-sorption expansion material that expands when Li is absorbed. The Li-sorption expansion material is separated from the positive electrode layer and the negative electrode layer. Effect of the Invention

[0008] According to the present invention, there is provided an all-solid-state battery having a shutdown function. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view illustrating a schematic view of a main part of an all-solid-state battery according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view illustrating a schematic view of a main portion of an all-solid-state battery according to a second embodiment. [Diagram 3] FIG. 3 is a cross-sectional view illustrating a schematic view of a main part of an all-solid-state battery according to a third embodiment. [Figure 4] FIG. 4 is a cross-sectional view illustrating a schematic view of a main part of an all-solid-state battery according to a fourth embodiment. [Diagram 5] FIG. 5 is a cross-sectional view illustrating a schematic view of a main part of an all-solid-state battery according to a fifth embodiment. [Figure 6] FIG. 6 is a cross-sectional view illustrating a schematic view of a main part of an all-solid-state battery according to a sixth embodiment. [Figure 7] FIG. 7 is a block diagram showing an all-solid-state battery system according to the seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an all-solid-state battery according to an embodiment of the present invention will be described with reference to the drawings.

[0011] In this specification, the term "all-solid-state battery" refers to a secondary battery in which the electrolyte layer and the electrode layers (positive electrode layer and negative electrode layer) are substantially solid. Each layer may be "substantially" solid, and a small amount of liquid material may be used.

[0012] (First embodiment) Fig. 1 is a cross-sectional view showing a schematic diagram of a main part of an all-solid-state battery 1 according to a first embodiment. Fig. 1(a) shows a configuration in a normal state. Meanwhile, Fig. 1(b) shows a configuration in a shutdown state.

[0013] As shown in FIG. 1(a), the all-solid-state battery 1 has a solid electrolyte layer 2, a positive electrode layer 3, and a negative electrode layer 4. The positive electrode layer 3 and the negative electrode layer 4 are arranged to sandwich the solid electrolyte layer 2 in the stacking direction. Although not shown, the positive electrode layer 3 is connected to an external device via, for example, a positive electrode current collector foil arranged on its outer surface. Similarly, the negative electrode layer 4 is also connected to an external device via, for example, a positive electrode current collector foil arranged on its outer surface.

[0014] The positive electrode layer 3 is a layer containing a positive electrode active material. The positive electrode layer 3 is configured to release lithium during charging and to absorb lithium during discharging. For example, the positive electrode layer 3 is formed of a material containing a resin binder and a positive electrode active material dispersed in the resin binder. The positive electrode active material is not particularly limited, but for example, an NMC-based positive electrode active material can be used.

[0015] The negative electrode layer 4 is a layer containing a negative electrode active material. The negative electrode active material absorbs lithium during charging and releases lithium during discharging. Alternatively, the negative electrode active material may be realized by metallic lithium that is precipitated on the solid electrolyte layer 2 during charging. That is, the all-solid-state battery 1 may be a "precipitation-type all-solid-state battery". In such a precipitation-type all-solid-state battery, there may be almost no metallic lithium as a negative electrode active material in a fully discharged state. However, at least metallic lithium that is precipitated as a negative electrode active material during charging functions as the negative electrode layer 4. Therefore, the precipitation-type all-solid-state battery is also included in the all-solid-state battery of this embodiment.

[0016] The solid electrolyte layer 2 is a layer through which lithium ions are conducted during charging and discharging. The solid electrolyte layer 2 includes a solid electrolyte and a Li-occlusion expansion material 5.

[0017] The solid electrolyte is a substance that has electronic insulation and ion conductivity. The solid electrolyte is not particularly limited, but for example, a sulfide solid electrolyte can be used.

[0018] The lithium occlusion expansion material 5 is a substance that expands when lithium is absorbed. The lithium occlusion expansion material 5 is separated from the positive electrode layer 3 and the negative electrode layer 4. That is, the lithium occlusion expansion material 5 is disposed inside the solid electrolyte layer 2.

[0019] The above is a schematic configuration of the all-solid-state battery 1 according to this embodiment. A shutdown function is realized according to this all-solid-state battery 1. This point will be described below.

[0020] First, during normal operation, lithium ions are conducted between the positive electrode layer 3 and the negative electrode layer 4 via the solid electrolyte layer 2. This causes charging and discharging to occur.

[0021] On the other hand, in the event of an abnormality (specifically, when lithium dendrites grow in the solid electrolyte layer 2), the Li-occluding expansion material 5 absorbs lithium. As a result, as shown in FIG. 1(b), the Li-occluding expansion material 5 expands. The expansion of the Li-occluding expansion material 5 generates voids in the solid electrolyte layer 2. This blocks the conduction path of lithium ions between the positive electrode layer 3 and the negative electrode layer 4, and the battery stops operating. In other words, the all-solid-state battery 1 shuts down.

[0022] The above is an outline of this embodiment.

[0023] The Li occlusion and expansion material 5 may be any material capable of imparting a shutdown function to the all-solid-state battery 1. The Li occlusion and expansion material 5 may be, for example, at least one selected from the group consisting of Si, SiO, Sn, S, Al, graphite, and hard carbon. A preferred Li occlusion and expansion material 5 may be at least one selected from the group consisting of Si, SiO, and Sn. The Li occlusion and expansion material 5 is preferably particulate.

[0024] Second Embodiment Next, a second embodiment will be described. Detailed description will be omitted for the fact that the same configuration as the first embodiment can be adopted. FIG. 2 is a cross-sectional view showing a schematic view of a main part of an all-solid-state battery 1 according to a second embodiment. FIG. 2(a) shows a configuration in a normal state. FIG. 2(b) shows a configuration in a shutdown state.

[0025] As shown in FIG. 2(a), the solid electrolyte layer 2 has an expansion material-containing layer 2-1 and an expansion material-free layer 2-2. The expansion material-containing layer 2-1 is a layer containing the Li-storage expansion material 5. The expansion material-free layer 2-2 is a layer lacking the Li-storage expansion material 5. The expansion material-containing layer 2-1 is disposed in the center in the thickness direction. The expansion material-free layer 2-2 is disposed at a position sandwiching the expansion material-containing layer 2-1 in the thickness direction.

[0026] In this embodiment, the lithium occlusion and expansion material 5 is concentrated in a certain region (the center in the thickness direction). Therefore, even if the total amount of the lithium occlusion and expansion material 5 is small, the shutdown function can be realized.

[0027] (Third embodiment) Next, a third embodiment will be described. Detailed description will be omitted for the fact that the same configuration as the above-described embodiment can be adopted. FIG. 3 is a cross-sectional view showing a schematic view of a main part of an all-solid-state battery 1 according to a third embodiment. FIG. 3(a) shows a normal configuration. FIG. 3(b) shows a shutdown configuration.

[0028] In this embodiment, the solid electrolyte layer 2 further includes a sheet-shaped support 7. The support 7 supports the solid electrolyte. The Li-storage expansion material 5 is disposed on a surface of the support 7. Specifically, the Li-storage expansion material 5 is disposed on both sides of the support 7.

[0029] Even if the configuration of this embodiment is adopted, the Li storage expansion material 5 can be concentrated in a certain region as in the second embodiment. Even if the amount of the Li storage expansion material 5 is small, the shutdown function can be realized. In addition, by using the support 7, the solid electrolyte layer 2 can be handled as a free-standing film.

[0030] For example, insulating resin, ceramic, fiber, etc. can be used as the support 7. Specific examples of the material of the support 7 include PET, acrylic resin, nylon, aramid, glass, alumina, etc. The support 7 may be a porous sheet.

[0031] The thickness of the support 7 is, for example, 100 μm or less, and preferably 20 μm or less.

[0032] The method for manufacturing the solid electrolyte layer 2 having the configuration of this embodiment is not particularly limited. For example, first, the support 7 is prepared. Then, a slurry containing the Li occlusion expansion material 5 is applied onto the surface of the support 7, and dried as necessary. Further, a slurry containing a solid electrolyte is applied onto the surface of the support 7, and dried as necessary. In this way, a free-standing film to be used as the solid electrolyte layer 2 can be obtained.

[0033] (Fourth embodiment) Next, a fourth embodiment will be described. Detailed description will be omitted for the fact that the same configuration as the above-described embodiments can be adopted. FIG. 4 is a cross-sectional view showing a schematic view of a main part of an all-solid-state battery 1 according to a fourth embodiment. FIG. 4(a) shows a normal configuration. FIG. 4(b) shows a shutdown configuration.

[0034] In this embodiment, as in the third embodiment, the solid electrolyte layer 2 has a sheet-shaped support 7. The solid electrolyte is supported by the support 7. The Li-storage expansion material 5 is also disposed on the surface of the support 7. However, unlike the third embodiment, the Li-storage expansion material 5 is disposed only on the surface of the support 7 on the negative electrode layer 4 side.

[0035] According to this embodiment, even if the amount of the Li occluding and expanding material 5 is even smaller, the shutdown function can be realized.

[0036] Moreover, lithium dendrites usually grow from the negative electrode layer 4 side. By disposing the Li-occluding and expanding material 5 on the surface of the support 7 on the negative electrode layer 4 side, it is possible to exert the shutdown function at an early stage of the growth of lithium dendrites. In other words, it is possible to suppress the growth of lithium dendrites at an early stage.

[0037] Fifth embodiment Next, a fifth embodiment will be described. Detailed description will be omitted for the fact that the same configuration as the above-described embodiments can be adopted. FIG. 5 is a cross-sectional view showing a schematic view of a main part of an all-solid-state battery 1 according to a fifth embodiment. FIG. 5(a) shows a normal configuration. FIG. 5(b) shows a shutdown configuration.

[0038] In this embodiment, the content of the Li occlusion expansion material 5 on the negative electrode layer 4 side of the solid electrolyte layer 2 is greater than that on the positive electrode layer 3 side. Specifically, the solid electrolyte layer 2 has a negative electrode side region 2-3 and a positive electrode side region 2-4. The content (concentration or density) of the Li occlusion expansion material 5 in the negative electrode side region 2-3 is greater than that in the positive electrode side region 2-4.

[0039] In this embodiment, similarly to the second to fourth embodiments, the Li-occluding and expanding material 5 is concentrated in a certain region. Therefore, even if the amount of the Li-occluding and expanding material 5 is small, the shutdown function can be realized. In addition, since the Li-occluding and expanding material 5 is disposed on the negative electrode layer 4 side where lithium dendrites grow, the growth of lithium dendrites can be suppressed at an early stage.

[0040] Sixth embodiment Next, a sixth embodiment will be described. Detailed description will be omitted for the fact that the same configuration as the above-described embodiments can be adopted. FIG. 6 is a cross-sectional view showing a schematic view of a main part of an all-solid-state battery 1 according to a sixth embodiment. FIG. 6(a) shows a normal configuration. FIG. 6(b) shows a shutdown configuration.

[0041] 6(a), when viewed along the stacking direction, the solid electrolyte layer 2 has a central portion and an outer peripheral portion. The content (concentration or density) of the Li-occluding expansion material 5 in the outer peripheral portion is greater than the content (concentration or density) of the Li-occluding expansion material 5 in the central portion.

[0042] Lithium dendrites tend to grow more easily in the outer periphery than in the center. According to this embodiment, the Li-occluding and expanding material 5 is concentrated in the outer periphery where lithium dendrites tend to grow. Therefore, a small amount of the Li-occluding and expanding material 5 can achieve the shutdown function.

[0043] Seventh embodiment Next, a seventh embodiment will be described. In this embodiment, an all-solid-state battery system 8 will be described.

[0044] 7 is a block diagram showing an all-solid-state battery system 8 according to the present embodiment. As shown in FIG. 7, the all-solid-state battery system 8 includes an all-solid-state battery 1, a restraint mechanism 9, an abnormality detection mechanism 10, and a control mechanism 11.

[0045] As the all-solid-state battery 1, the one described in the above embodiment is used.

[0046] The restraining mechanism 9 is configured to restrain the all-solid-state battery 1. The restraining mechanism 9 applies a compressive restraining force to the all-solid-state battery 1. The restraining mechanism 9 is realized by, for example, an elastic member such as a rubber band. In order to obtain a desired function in the all-solid-state battery 1, it is usually necessary that the electrode layers (the positive electrode layer 3 and the negative electrode layer 4) are firmly bonded to the solid electrolyte layer 2. By providing the restraining mechanism 9, it is possible to obtain desired battery characteristics during normal operation.

[0047] The abnormality detection mechanism 10 is configured to detect an abnormality in the all-solid-state battery 1. Specifically, the abnormality detection mechanism 10 is configured to detect precipitation of lithium dendrites in the solid electrolyte layer 2. The precipitation of lithium dendrites can be detected, for example, by measuring the electrical characteristics (current, voltage, etc.) of the all-solid-state battery 1. That is, the abnormality detection mechanism 10 can be realized by an ammeter, a voltmeter, etc. The abnormality detection mechanism 10 is configured to notify the control mechanism 11 of the detection result upon detecting the precipitation of lithium dendrites.

[0048] The control mechanism 11 controls the operation of the restraint mechanism 9. Specifically, when the abnormality detection mechanism 10 detects an abnormality, the control mechanism 11 reduces the restraint force on the all-solid-state battery 1. The control mechanism 11 is realized by, for example, a computer.

[0049] According to this embodiment, during normal operation, the all-solid-state battery 1 is pressurized by the restraining mechanism 9 so as to be compressed. On the other hand, during an abnormality (when lithium dendrites precipitate), the restraining force on the all-solid-state battery 1 is reduced. If the all-solid-state battery 1 is pressurized even during an abnormality, voids are unlikely to occur in the solid electrolyte layer 2 even if the Li-occluding expansion material 5 expands. In other words, it is difficult to realize the shutdown function. However, according to this embodiment, the restraining force on the all-solid-state battery 1 is reduced during an abnormality, so that voids are likely to occur in the solid electrolyte layer 2 due to the expansion of the Li-occluding expansion material 5. Therefore, the shutdown function can be exerted earlier during an abnormality.

[0050] The present invention has been described above using the first to seventh embodiments. Representative configurations of the present invention and their functions and effects will be summarized below as supplementary notes.

[0051] (Appendix 1) An all-solid-state battery comprising: a solid electrolyte layer 2; and a positive electrode layer 3 and a negative electrode layer 4 arranged to sandwich the solid electrolyte layer 2 in a stacking direction, the solid electrolyte layer 2 containing a solid electrolyte and a Li-sorption expansion material 5 that expands when Li is absorbed, the Li-sorption expansion material 5 being separated from the positive electrode layer 3 and the negative electrode layer 4.

[0052] According to the above-mentioned configuration, the all-solid-state battery 1 can be provided with a shutdown function.

[0053] (Appendix 2) 2. The all-solid-state battery according to claim 1, wherein the Li occlusion expansion material 5 is configured to generate voids in the solid electrolyte layer by expanding when occluding Li.

[0054] According to the above-mentioned configuration, the all-solid-state battery 1 can be provided with a shutdown function.

[0055] (Appendix 3) 3. The all-solid-state battery according to claim 1 or 2, wherein the solid electrolyte layer 2 has an expansion material-containing layer 2-1 containing the Li-occlusion expansion material 5 and an expansion material-free layer 2-2 lacking the Li-occlusion expansion material 5.

[0056] According to the above-mentioned configuration, a small amount of the Li occluding and expanding material 5 can provide the shutdown function.

[0057] (Appendix 4) 4. The all-solid-state battery according to any one of claims 1 to 3, wherein the solid electrolyte layer 2 further includes a sheet-like support 7 supporting the solid electrolyte, and the Li occlusion and expansion material 5 is disposed on a surface of the support.

[0058] According to the above-mentioned configuration, it is possible to impart a shutdown function with a small amount of the Li occlusion and expansion material 5. In addition, it is possible to impart self-supporting property to the solid electrolyte layer 2.

[0059] (Appendix 5) 5. The all-solid-state battery according to claim 4, wherein the Li-occlusion expansion material 5 is disposed on a surface of the support 7 on the negative electrode layer side.

[0060] According to the above-mentioned configuration, when an abnormality occurs, a shutdown can be performed early.

[0061] (Appendix 6) 6. The all-solid-state battery according to any one of claims 1 to 5, wherein in the solid electrolyte layer 2, the content of the Li occlusion expansion material 5 is greater on the negative electrode layer 4 side than on the positive electrode layer 3 side.

[0062] According to the above-mentioned configuration, when an abnormality occurs, a shutdown can be performed early.

[0063] (Appendix 7) 7. The all-solid-state battery according to any one of claims 1 to 6, wherein, when viewed along the stacking direction, the content of the Li-occluding expansion material 5 in the outer periphery of the solid electrolyte layer 2 is greater than the content of the Li-occluding expansion material 5 in the central portion of the solid electrolyte layer 2.

[0064] According to the above-mentioned configuration, a small amount of the Li occlusion expansion material 5 can realize the shutdown function.

[0065] (Appendix 8) An all-solid-state battery system comprising: an all-solid-state battery 1 according to any one of Appendices 1 to 7; a restraint mechanism 9 for restraining the all-solid-state battery 1; a control mechanism 11 for controlling the operation of the restraint mechanism 9; and an abnormality detection mechanism 10 for detecting an abnormality in the all-solid-state battery, wherein the control mechanism 11 controls the restraint mechanism 9 such that the restraint force on the all-solid-state battery 1 is reduced when the abnormality detection mechanism 10 detects an abnormality.

[0066] According to the above-mentioned configuration, the shutdown function can be performed earlier in the event of an abnormality.

[0067] (Appendix 9) 3. A shutdown method for the all-solid-state battery according to claim 1, comprising: detecting an abnormality in a solid electrolyte layer; and reducing a restraining force of the all-solid-state battery when the abnormality in the solid electrolyte layer is detected. [Explanation of symbols]

[0068] 1 All-solid-state battery, 2 Solid electrolyte layer, 2-1 Expansion material-containing layer, 2-2 Expansion material-free layer, 2-3 Negative electrode region, 2-4 Positive electrode region, 3 Positive electrode layer, 4 Negative electrode layer, 5 Lithium storage expansion material, 6 Lithium dendrite, 7 Support, 8 All-solid-state battery system, 9 Restraint mechanism, 10 Abnormality detection mechanism, 11 Control mechanism

Claims

1. A solid electrolyte layer; a positive electrode layer and a negative electrode layer disposed so as to sandwich the solid electrolyte layer in a stacking direction; Equipped with The solid electrolyte layer is A solid electrolyte; A lithium occlusion expansion material that expands when lithium is absorbed, The Li-occlusion expansion material is separated from the positive electrode layer and the negative electrode layer. All-solid-state battery.

2. The all-solid-state battery according to claim 1 , The lithium occlusion expansion material is configured to generate voids in the solid electrolyte layer by expanding when lithium is absorbed. All-solid-state battery.

3. The all-solid-state battery according to claim 1 or 2, The solid electrolyte layer is an expansion material-containing layer containing the Li-occluding expansion material; and an expansion material-free layer lacking the Li-occluding expansion material. All-solid-state battery.

4. The all-solid-state battery according to claim 1 or 2, The solid electrolyte layer further includes a sheet-like support that supports the solid electrolyte, The Li-occluding expansion material is disposed on a surface of the support. All-solid-state battery.

5. The all-solid-state battery according to claim 4, The lithium occlusion expansion material is disposed on a surface of the support on the negative electrode layer side. All-solid-state battery.

6. The all-solid-state battery according to claim 1 or 2, In the solid electrolyte layer, the content of the lithium occlusion expansion material is higher on the negative electrode layer side than on the positive electrode layer side. All-solid-state battery.

7. The all-solid-state battery according to claim 1 or 2, When viewed along the stacking direction, the content of the lithium occlusion expansion material in the outer periphery of the solid electrolyte layer is greater than the content of the lithium occlusion expansion material in the central portion of the solid electrolyte layer. All-solid-state battery.

8. The all-solid-state battery according to claim 1 or 2, A restraining mechanism that restrains the all-solid-state battery; A control mechanism for controlling an operation of the restraint mechanism; An abnormality detection mechanism that detects an abnormality in the all-solid-state battery; Equipped with The control mechanism controls the restraining mechanism so that a restraining force on the all-solid-state battery is reduced when the abnormality detection mechanism detects an abnormality. All-solid-state battery system.

9. A method for shutting down an all-solid-state battery according to claim 1 or 2, comprising: detecting an abnormality in the solid electrolyte layer; and reducing a restraining force of the all-solid-state battery when an abnormality in the solid electrolyte layer is detected. How to shut down.

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