Secondary batteries

Abstract

The present invention provides a secondary battery that can apply sufficient pressure to the charge and discharge regions even in the outer periphery, and can suppress lateral displacement of the negative electrode layer. [Solution] The device comprises a first elastic member 2, a negative electrode current collector 3 disposed on the first elastic member, a negative electrode layer 4, an electrolyte layer 5 containing a solid electrolyte, a positive electrode layer 6, a positive electrode current collector foil 7, and a second elastic member 8 having a frame-shaped portion 8-1 that surrounds the negative electrode layer and the first elastic member in a direction perpendicular to the lamination direction. The second elastic member 8 has a larger Young's modulus than the first elastic member 2. The inner surface of the frame-shaped portion 8-1 is in contact with the outer surface of the negative electrode layer 4. At least in the charged state, the outer surface of the first elastic member 2 is in contact with the outer surface of the frame-shaped portion 8-1.

Description

Technical Field

[0006] ,

[0001] The present invention relates to a secondary battery.

Background Art

[0002] Secondary batteries using solid electrolytes are known. As such a secondary battery, one having a configuration in which a negative electrode layer, an electrolyte layer, and a positive electrode layer are laminated in this order is known.

[0003] In the secondary battery as described above, the electrode layer may expand and contract during charge and discharge. In particular, the negative electrode layer is likely to expand and contract. Therefore, the secondary battery needs to have a configuration that allows the expansion and contraction of the negative electrode layer.

[0004] In relation to the above, Patent Document 1 (Japanese Patent Application Laid-Open No. 2022-074125) describes an invention related to a bipolar all-solid-state secondary battery including an electrode structure. The electrode structure described in Patent Document 1 includes a specific current collector having a folded structure, a specific positive electrode active material layer, a specific negative electrode active material layer, and a compression pad disposed inside the folded structure of the current collector. According to the description of Patent Document 1, this electrode structure can absorb the volume change of the negative electrode during charge and discharge and protect the negative electrode layer, so that the durability of the battery can be improved.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To allow for expansion and contraction of the negative electrode layer in the stacking direction, it is conceivable to use an elastic member. By placing the elastic member in a position overlapping with the negative electrode layer in the stacking direction, the expansion and contraction in the stacking direction will be absorbed by the elastic member. In other words, expansion and contraction of the negative electrode layer will be allowed.

[0007] On the other hand, in secondary batteries using solid electrolytes, the charge-discharge region (the region where the positive electrode layer, electrolyte layer, and negative electrode layer overlap) is usually pressurized in the stacking direction to obtain good charge-discharge characteristics. It is desirable that the charge-discharge region be pressurized uniformly. However, when an elastic member is used, pressure tends to escape easily at the outer periphery of the elastic member. As a result, the outer periphery of the charge-discharge region is less susceptible to pressure compared to the central part.

[0008] Furthermore, the negative electrode layer may expand and contract in a direction perpendicular to the stacking direction (hereinafter sometimes referred to as the lateral direction). Repeated expansion and contraction in the lateral direction may cause the negative electrode layer to shift laterally. This lateral displacement can worsen the cycle characteristics. Therefore, it is necessary to suppress the lateral displacement of the negative electrode layer.

[0009] Therefore, an object of the present invention is to provide a secondary battery that can apply sufficient pressure to the charge and discharge regions even in the outer periphery, and can suppress displacement of the negative electrode layer in the lateral direction. [Means for solving the problem]

[0010] In one embodiment, the secondary battery according to the present invention comprises a first elastic member, a negative electrode current collector disposed on the first elastic member, a negative electrode layer disposed on the negative electrode current collector, an electrolyte layer disposed on the negative electrode layer and containing a solid electrolyte, a positive electrode layer disposed on the electrolyte layer, a positive electrode current collector foil disposed on the positive electrode layer, and a second elastic member having a frame-shaped portion that surrounds the negative electrode layer and the first elastic member in a direction perpendicular to the lamination direction. The second elastic member has a larger Young's modulus than the first elastic member. The inner surface of the frame-shaped portion is in contact with the outer surface of the negative electrode layer. At least in the charged state, the outer surface of the first elastic member is in contact with the outer surface of the frame-shaped portion. [Effects of the Invention]

[0011] According to the present invention, a secondary battery is provided that can apply sufficient pressure to the charge and discharge regions even in the outer periphery, and can suppress displacement of the negative electrode layer in the lateral direction. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view showing a secondary battery according to the first embodiment. [Figure 2] Figure 2 is a plan view showing the first elastic member. [Figure 3] Figure 3 is a schematic cross-sectional view showing the operation method of a secondary battery according to the first embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing a modified example of the first embodiment. [Figure 5] Figure 5 is a schematic diagram showing a modified example of the first embodiment. [Figure 6A] Figure 6A is a plan view showing a second elastic member according to a modified example of the first embodiment. [Figure 6B] Figure 6B is a plan view showing a second elastic member according to a modified example of the first embodiment. [Figure 6C] Figure 6C is a plan view showing a second elastic member according to a modified example of the first embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view showing a secondary battery according to the second embodiment. [Figure 8] FIG. 8 is a plan view showing the second elastic member. [Figure 9] FIG. 9 is a schematic cross-sectional view showing a modified example of the second embodiment. [Figure 10A] FIG. 10A is a schematic cross-sectional view showing a secondary battery according to the third embodiment. [Figure 10B] FIG. 10B is a plan view schematically showing the shapes of the first elastic member and the second elastic member. [Figure 11] FIG. 11 is a schematic cross-sectional view showing a secondary battery according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] (1) First Embodiment FIG. 1 is a schematic cross-sectional view showing a secondary battery 1 according to the first embodiment. As shown in FIG. 1, the secondary battery 1 includes a first elastic member 2, a second elastic member 8, a negative electrode current collector 3, a negative electrode layer 4, an electrolyte layer 5, a positive electrode layer 6, and a positive electrode current collector 7.

[0015] The first elastic member 2, the negative electrode current collector 3, the negative electrode layer 4, the electrolyte layer 5, the positive electrode layer 6, and the positive electrode current collector 7 are laminated in this order along the lamination direction. In the example shown in FIG. 1, a laminated structure including a negative electrode current collector 3, a negative electrode layer 4, an electrolyte layer 5, a positive electrode layer 6, and a positive electrode current collector 7 as one unit includes two units (a first unit and a second unit). Specifically, the negative electrode current collector 3, the negative electrode layer 4, the electrolyte layer 5, the positive electrode layer 6, and the positive electrode current collector 7 are laminated in this order on each side of the first elastic member 2 in the lamination direction. Although not shown, this laminated structure is pressed so as to be compressed from above and below in the lamination direction.

[0016] The first elastic member 2 is provided to allow expansion and contraction of the negative electrode layer 4 in the lamination direction. The first elastic member 2 is formed of, for example, a member having a lower Young's modulus than the negative electrode layer 4, the electrolyte layer 5, and the positive electrode layer 6.

[0017] The second elastic member 8 is provided to prevent displacement of the negative electrode layer 4 and to prevent pressure leakage at the outer periphery. The second elastic member 8 has a larger Young's modulus than the first elastic member 2.

[0018] Figure 2 is a plan view showing the second elastic member 8. As shown in Figures 1 and 2, the second elastic member 8 has a frame-shaped portion 8-1. The frame-shaped portion 8-1 surrounds the negative electrode layer 4 and the first elastic member 2 in a direction perpendicular to the lamination direction (lateral direction). The inner surface of the frame-shaped portion 8-1 is in contact with the inner surface of the negative electrode layer 4. At least in the charged state, the inner surface of the frame-shaped portion 8-1 is also in contact with the outer surface of the first elastic member 2.

[0019] The negative electrode current collector 3 is provided to electrically connect the negative electrode layer 4 to an external device. As shown in Figure 1, the negative electrode current collector 3 is positioned on the first elastic member 2. The negative electrode current collector 3 extends laterally from the connection point with the negative electrode layer 4. Specifically, the second elastic member 8 (frame-shaped portion 8-1) is provided with a gap (opening 10) through which the negative electrode current collector 3 passes. The negative electrode current collector 3 is drawn outwards through this gap. For example, SUS foil can be used as the negative electrode current collector 3.

[0020] The negative electrode layer 4 is located on the negative electrode current collector 3. The negative electrode layer 4 is a layer containing a negative electrode active material. The negative electrode active material is not particularly limited, but examples include silicon-based active materials. The negative electrode layer 4 is configured to take in lithium ions during charging and release lithium ions during discharging.

[0021] The electrolyte layer 5 is located on the negative electrode layer 4. The electrolyte layer 5 is configured to conduct lithium ions between the negative electrode layer 4 and the positive electrode layer 6 during charging and discharging. The electrolyte layer 5 contains a solid electrolyte. The electrolyte layer 5 as a whole is solid. The solid electrolyte is not particularly limited, but examples include argyrodite-type electrolytes.

[0022] The positive electrode layer 6 is located on the electrolyte layer 5. The positive electrode layer 6 contains a positive electrode active material. The positive electrode layer 6 may also contain a conductive additive, a solid electrolyte, and a resin binder. The positive electrode layer 6 is configured to release lithium ions during charging and to take in lithium ions during discharging.

[0023] The positive electrode current collector 7 is positioned on the positive electrode layer 6. The positive electrode current collector 7 is provided to electrically connect the positive electrode layer 6 to an external device. The positive electrode current collector 7 extends laterally from the connection point with the positive electrode layer 6. For example, aluminum foil can be used as the positive electrode current collector 7.

[0024] The above is a schematic configuration of the secondary battery 1 according to this embodiment. In this secondary battery 1, charging and discharging are performed in the charging and discharging region. The charging and discharging region is, as previously described, the region in which the negative electrode layer 4, the electrolyte layer 5, and the positive electrode layer 6 overlap.

[0025] Figure 3 is a schematic cross-sectional view showing the configuration of the secondary battery 1 in the charged and discharged states according to this embodiment. Figure 3(a) shows the configuration in the discharged state, and Figure 3(b) shows the configuration in the charged state. Note that the positive electrode layer 6 and the positive electrode current collector 7 are not shown in Figure 3.

[0026] During charging, lithium ions move from the positive electrode layer 6 to the negative electrode layer 4 via the electrolyte layer. Conversely, during discharging, lithium ions move from the negative electrode layer 4 to the positive electrode layer 6. During charging and discharging, electrochemical reactions mediated by lithium ions proceed in each electrode layer. As a result of these electrochemical reactions, each electrode layer expands and contracts. The negative electrode layer 4, in particular, is prone to expansion and contraction. Specifically, the negative electrode layer 4 expands during charging and contracts during discharging.

[0027] In this embodiment, since the first elastic member 2 is provided, expansion and contraction of the negative electrode layer 4 in the stacking direction is permitted. Specifically, the thickness of the first elastic member 2 changes as the negative electrode layer 4 expands and contracts in the stacking direction. If the secondary battery 1 has a configuration that does not allow for expansion and contraction in the stacking direction, that is, if the first elastic member 2 is absent, then large stresses may be generated in the components of the secondary battery 1 during charging and discharging. As a result, the components of the secondary battery 1 may be damaged. In contrast, in this embodiment, the expansion and contraction of the negative electrode layer 4 in the stacking direction is absorbed by the first elastic member 2. Therefore, damage to the components of the secondary battery 1 is prevented.

[0028] On the other hand, simply providing the first elastic member 2 may cause pressure loss at the outer periphery. From the viewpoint of allowing expansion and contraction of the negative electrode layer 4 in the lamination direction, the first elastic member 2 should be soft. That is, the Young's modulus of the first elastic member 2 should be low. However, if a material with a low Young's modulus is used as the first elastic member 2, pressure loss at the outer periphery is more likely to occur. In other words, it becomes more difficult to apply pressure to the outer periphery of the charge-discharge region (as described above, the region where the positive electrode layer 6, electrolyte layer 5, and negative electrode layer 4 overlap).

[0029] However, in this embodiment, since the second elastic member 8 is provided, pressure loss is suppressed. Specifically, the outer surface of the first elastic member 2 is surrounded by the second elastic member 8, which has a higher Young's modulus. At least in the charged state (see Figure 3(b)), the outer surface of the first elastic member 2 is in contact with the second elastic member 8 (frame-shaped portion 8-1). Therefore, even if a soft material is used as the first elastic member 2, pressure loss at its outer periphery is suppressed. As a result, sufficient pressure can be applied to the charge and discharge region even at the outer periphery.

[0030] Furthermore, according to this embodiment, the negative electrode layer 4 is surrounded by the second elastic member 8. Therefore, the lateral displacement of the negative electrode layer 4 is suppressed by the second elastic member 8.

[0031] As described above, according to this embodiment, since the first elastic member 2 and the second elastic member 8, each having a specific configuration, are provided, sufficient pressure can be applied to the charge and discharge region even in the outer periphery. Furthermore, displacement of the negative electrode layer in the lateral direction can be suppressed.

[0032] In the example shown in Figure 3, the outer surface of the first elastic member 2 is separated from the second elastic member 8 during the discharge state (see Figure 3(a)). As shown in the example in Figure 3, the outer surface of the first elastic member 2 may be separated from the second elastic member 8 during discharge. At least during charging (see Figure 3(b)), if the outer surface of the first elastic member 2 is in contact with the second elastic member 8, it will have a certain effect in preventing pressure loss.

[0033] However, preferably, the outer surface of the first elastic member 2 is in contact with the inner surface of the frame-shaped portion 8-1 regardless of the charging and discharging state. With this configuration, pressure leakage is prevented regardless of the charging and discharging state. More preferably, the outer surface of the first elastic member 2 is "adhered" to the inner surface of the frame-shaped portion 8-1. With this configuration, the outer surface of the first elastic member 2 and the inner surface of the frame-shaped portion 8-1 can be brought into contact regardless of the charging and discharging state.

[0034] The first elastic member 2 and the second elastic member 8 may be mechanically connected. Figure 4 is a schematic cross-sectional view showing one modified example of this embodiment. The secondary battery 1 according to this modified example has a connecting member 9. The connecting member 9 is configured to connect the first elastic member 2 and the second elastic member 8. By using such a connecting member 9, the outer surface of the first elastic member 2 and the inner surface of the frame-shaped portion 8-1 can be brought into contact regardless of the charge / discharge state.

[0035] As previously described, the frame-shaped portion 8-1 is in contact with the outer surface of the negative electrode layer 4 (see Figure 1, etc.). In the example shown in Figure 1, the frame-shaped portion 8-1 "completely" covers the outer surface of the negative electrode layer 4. That is, the outer surface of the negative electrode layer 4 is covered by the frame-shaped portion 8-1 in its entirety in the stacking direction (thickness direction). With this configuration, displacement of the negative electrode layer 4 in the lateral direction is more reliably suppressed.

[0036] On the other hand, the outer surface of the negative electrode layer 4 does not necessarily need to be covered by the frame-shaped portion 8-1 over its entire length in the stacking direction. For example, the area covered (in contact with) by the frame-shaped portion 8-1 may be only a portion of the outer surface of the negative electrode layer 4 in the stacking direction. Even with such a configuration, displacement of the negative electrode layer 4 is prevented at least in the portion covered by the frame-shaped portion 8-1. Therefore, a certain effect can be obtained in preventing displacement of the negative electrode layer 4.

[0037] In this embodiment, the case described is one in which the secondary battery 1 has two units (a first unit and a second unit), as shown in Figure 1. However, the number of units included in the secondary battery 1 is not particularly limited. Figure 5 is a schematic diagram showing a modified example of this embodiment. In this modified example, the number of units is one. That is, the negative electrode current collector 3, negative electrode layer 4, electrolyte layer 5, positive electrode layer 6, and positive electrode current collector 7 are each single. As shown in the example in Figure 5, the number of units may be single. Also, although not shown, the number of units may be three or more.

[0038] In this embodiment, the case in which the second elastic member 8 consists of a frame-shaped portion 8-1, as shown in Figures 1 and 2, has been described. That is, the case in which the second elastic member 8 has no parts other than the frame-shaped portion 8-1 has been described. However, the second elastic member 8 may include other parts in addition to the frame-shaped portion 8-1. Figures 6A to 6C are plan views showing the second elastic member 8 according to a modified example of this embodiment. In each modified example, the second elastic member 8 has a protruding portion 8-2 in addition to the frame-shaped portion 8-1. Although not reflected in Figures 6A to 6C, the protruding portion 8-2 extends from the inner surface of the frame-shaped portion 8-1 so as to protrude toward the inside of the first elastic member 2. That is, the protruding portion 8-2 is formed in the layer in which the first elastic member 2 is arranged. In the example shown in Figure 6A, the protruding portion 8-2 is cross-shaped. In the example shown in Figure 6B, the projection 8-2 extends inward from two opposing sides of the frame-shaped portion 8-1, widening at its inner end. In the example shown in Figure 6C, the projection 8-2 extends inward from two opposing sides of the frame-shaped portion 8-1. The shape of the second elastic member 8 in this embodiment may be as shown in Figures 6A to 6C. That is, the second elastic member 8 only needs to have the frame-shaped portion 8-1, and the presence or shape of other parts is not particularly limited.

[0039] (2) Second embodiment Next, we will describe the second embodiment. We will omit detailed explanations regarding aspects where the same configuration as the first embodiment can be adopted.

[0040] Figure 7 is a schematic cross-sectional view showing a secondary battery 1 according to the seventh embodiment. Figure 8 is a plan view showing the second elastic member 8 in this embodiment.

[0041] As shown in Figures 7 and 8, in this embodiment, the second elastic member 8 has a bottom portion 8-3 in addition to the frame-shaped portion 8-1. The bottom portion 8-3 is positioned to close the opening of the frame-shaped portion 8-1. The bottom portion 8-3 is integral with the frame-shaped portion 8-1. As shown in Figure 1, the first elastic member 2 is positioned on both sides of the bottom portion 8-3 in the stacking direction. That is, the first elastic member 2 is positioned between the bottom portion 8-3 and the negative electrode current collector 3 in the stacking direction.

[0042] According to this embodiment, since a bottom portion 8-3 is provided in addition to the frame-shaped portion 8-1, the position of the second elastic member 8 is less likely to shift. As a result, the positional shift of the negative electrode layer 4 in the lateral direction is more reliably prevented.

[0043] Furthermore, according to this embodiment, the charge / discharge region is positioned on the bottom portion 8-3 of the second elastic member 8, which has a high Young's modulus. That is, when viewed along the stacking direction, the bottom portion 8-3 of the second elastic member 8, which has a high Young's modulus, is positioned to overlap the entire charge / discharge region. Therefore, it becomes possible to apply pressure more uniformly to the entire charge / discharge region.

[0044] In the example shown in Figure 7, the first elastic member 2 is placed on each of the two sides of the bottom portion 8-3. However, the first elastic member 2 may be placed on only one side of the bottom portion 8-3. Figure 9 is a schematic cross-sectional view showing a modified example of this embodiment. In this modified example, the negative electrode current collector 3 is placed on one surface of the bottom portion 8-3 without the first elastic member 2. On the other hand, the first elastic member 2 is placed on the other surface of the bottom portion 8-3. Even if such a configuration is adopted, the same effects as in the example shown in Figure 7 can be obtained. In other words, the stacking order of the bottom portion 8-3 and the first elastic member 2 is not particularly limited. The stacking order may be bottom portion 8-3, first elastic member 2 and negative electrode current collector 3, or first elastic member 2, bottom portion 8-3 and negative electrode current collector 3.

[0045] (3) Third Embodiment Next, we will describe a third embodiment. Note that we will omit detailed explanations regarding aspects where the same configuration as the previously described embodiments can be adopted.

[0046] Figure 10A is a schematic cross-sectional view showing a secondary battery 1 according to the third embodiment. Figure 10B is a schematic plan view showing the shapes of the first elastic member 2 and the second elastic member 8.

[0047] As shown in Figures 10A and 10B, the second elastic member 8 has an inner projection 8-4 in addition to the frame-shaped portion 8-1. The inner projection 8-4 is provided on the inner surface of the frame-shaped portion 8-1 and protrudes inward. As shown in Figure 10B, the inner projection 8-4 is provided around the entire circumference of the inner surface of the frame-shaped portion 8-1. However, unlike the bottom portion 8-3 in Figure 7 (second embodiment), the inner projection 8-4 does not close the opening of the frame-shaped portion 8-1. The first elastic member 2 is positioned in the region inside the inner projection 8-4.

[0048] As shown in Figure 10A, the thickness of the inner projection 8-4 is less than the thickness of the first elastic member 2. The inner projection 8-4 extends from the outer surface of the first elastic member 2 and inwards towards the first elastic member 2. As a result, in the lamination direction, the inner projection 8-4 is sandwiched between the first elastic member 2.

[0049] When viewed along the stacking direction, the inner protrusion 8-4 overlaps with the outer periphery of the charge / discharge region.

[0050] According to this embodiment, an inner projection 8-4 having a Young's modulus greater than that of the first elastic member 2 is positioned at a location overlapping with the outer periphery of the charge / discharge region. Therefore, pressure leakage in the outer periphery can be suppressed more reliably.

[0051] (4) Fourth Embodiment Next, we will describe the fourth embodiment. We will omit detailed explanations regarding aspects where the same configuration as the previously described embodiments can be adopted.

[0052] Figure 11 is a schematic cross-sectional view showing a secondary battery 1 according to the fourth embodiment. In this embodiment, as in the third embodiment, an inner projection 8-4 that protrudes inward is provided on the inner surface of the frame-shaped portion 8-1. The inner projection 8-4 is positioned to surround the outer surface of the first elastic member 2. When viewed along the stacking direction, the inner projection 8-4 overlaps the outer periphery of the charge / discharge region.

[0053] However, unlike the third embodiment, in this embodiment, the thickness of the inner protrusion 8-4 is approximately the same as the thickness of the first elastic member 2. That is, unlike the third embodiment, the first elastic member 2 is not present on either side of the inner protrusion 8-4 in the stacking direction. The negative electrode current collector 3 is placed on the inner protrusion 8-4 without the second elastic member 8, and the outer periphery of the negative electrode layer 4 (the outer periphery of the charge / discharge region) is placed on top of it.

[0054] In this embodiment as well, since the inner protrusion 8-4 of the second elastic member 8, which has a high Young's modulus, is provided at a position overlapping with the outer periphery of the charge / discharge region, pressure leakage at the ends is prevented. Furthermore, since the charge / discharge region is positioned on the inner protrusion 8-4 without going through the first elastic member 2, which is soft (has a low Young's modulus), pressure leakage is even less likely to occur.

[0055] [Note] The main components and their effects included in this invention are summarized below as an appendix. (Note 1) A secondary battery comprising: a first elastic member 2; a negative electrode current collector 3 disposed on the first elastic member; a negative electrode layer 4 disposed on the negative electrode current collector; an electrolyte layer 5 disposed on the negative electrode layer and containing a solid electrolyte; a positive electrode layer 6 disposed on the electrolyte layer; a positive electrode current collector 7 disposed on the positive electrode layer; and a second elastic member 8 having a frame-shaped portion 8-1 that surrounds the negative electrode layer and the first elastic member in a direction perpendicular to the stacking direction, wherein the second elastic member 8 has a larger Young's modulus than the first elastic member 2; the inner surface of the frame-shaped portion 8-1 is in contact with the outer surface of the negative electrode layer 4; and at least in the charged state, the outer surface of the first elastic member 2 is in contact with the outer surface of the frame-shaped portion 8-1.

[0056] With the above configuration, since the second elastic member 8 is provided, pressure leakage in the outer periphery is suppressed. Therefore, sufficient pressure can be applied to the charge and discharge region even in the outer periphery. In addition, since the second elastic member 8 is provided, displacement of the negative electrode layer 4 in the lateral direction is prevented.

[0057] (Note 2) A secondary battery as described in Appendix 1, wherein the frame-shaped portion 8-1 is provided with an opening 10 through which the negative electrode current collector 3 passes.

[0058] According to the above configuration, the negative electrode current collector 3 can be drawn laterally from the charging / discharging area and connected to an external device.

[0059] (Note 3) A secondary battery as described in Appendix 1 or 2, wherein the outer surface of the first elastic member 2 is in contact with the inner surface of the frame-shaped portion 8-1 regardless of the charge / discharge state.

[0060] According to the above configuration, pressure loss at the outer circumference can be suppressed regardless of the charging and discharging state.

[0061] (Note 4) A secondary battery as described in Appendix 3, wherein the outer surface of the first elastic member 2 is bonded to the inner surface of the frame-shaped portion 8-1.

[0062] According to the above configuration, the outer surface of the first elastic member 2 and the frame-shaped portion 8-1 can always be kept in contact.

[0063] (Note 5) A secondary battery as described in Appendix 3 or 4, wherein the first elastic member 2 and the second elastic member 8 are connected via a connecting member 9.

[0064] According to the above configuration, the outer surface of the first elastic member 2 and the frame-shaped portion 8-1 can always be kept in contact.

[0065] (Note 6) A secondary battery as described in any of Appendix 1 to 5, wherein the frame-shaped portion 8-1 completely covers the outer surface of the negative electrode layer 4.

[0066] According to the above configuration, the displacement of the negative electrode layer 4 in the lateral direction can be suppressed more reliably.

[0067] (Note 7) A secondary battery as described in any of the appendices 1 to 6, wherein the second elastic member 8 further comprises a bottom portion 8-3 arranged to close the opening of the frame-shaped portion 8-1, and the bottom portion 8-3, the frame-shaped portion and 8-1 are integrally formed.

[0068] According to the above configuration, since the bottom portion 8-3, which has a large Young's modulus, is positioned to overlap the entire area of ​​the negative electrode layer 4, in-plane pressure variation can be reduced.

[0069] (Note 8) A secondary battery as described in any of the appendices 1 to 6, wherein the inner surface of the frame-shaped portion 8-1 is provided with an inner projection 8-4 that protrudes inward, the inner projection 8-4 is sandwiched by the first elastic member 2 in the stacking direction, and when viewed along the stacking direction, the inner projection 8-4 overlaps the outer periphery of the charge / discharge region, and the charge / discharge region is the region in which the negative electrode layer 4, the electrolyte layer 5, and the positive electrode layer 6 overlap in the stacking direction.

[0070] According to the above configuration, since the inner protrusion 8-4, which has a large Young's modulus, is positioned to overlap the outer periphery of the charge / discharge region, pressure leakage at the edges is more reliably suppressed. Sufficient pressure can also be applied to the outer periphery of the charge / discharge region.

[0071] (Note 9) A secondary battery as described in any of the appendices 1 to 6, wherein an inner projection 8-4 is provided on the inner surface of the frame-shaped portion 8-1, projecting inward, the inner projection 8-4 is positioned to surround the first elastic member 2, the thickness of the inner projection 8-4 is equal to the thickness of the first elastic member 2, and when viewed along the stacking direction, the inner projection 8-4 overlaps the outer periphery of the charge / discharge region, the charge / discharge region is the region in which the negative electrode layer 4, the electrolyte layer 5, and the positive electrode layer 6 overlap in the stacking direction.

[0072] According to the above configuration, since the inner protrusion 8-4, which has a large Young's modulus, is positioned to overlap the outer periphery of the charge / discharge region, pressure leakage at the edges is more reliably suppressed. Sufficient pressure can also be applied to the outer periphery of the charge / discharge region. [Explanation of Symbols]

[0073] 1...Secondary battery, 2...First elastic member, 3...Negative electrode current collector, 4...Negative electrode layer, 5...Electrolyte layer, 6...Positive electrode layer, 7...Positive electrode current collector, 8...Second elastic member, 8-1...Frame-shaped part, 8-2...Protruding part, 8-3...Bottom part, 8-4...Inner protruding part, 9...Connecting member

Claims

1. First elastic member and A negative electrode current collector disposed on the first elastic member, A negative electrode layer disposed on the negative electrode current collector, An electrolyte layer, which is disposed on the negative electrode layer and contains a solid electrolyte, A positive electrode layer disposed on the electrolyte layer, A positive electrode current collector foil arranged on the positive electrode layer, A second elastic member having a frame-shaped portion that surrounds the negative electrode layer and the first elastic member in a direction perpendicular to the lamination direction, Equipped with, The second elastic member has a larger Young's modulus than the first elastic member. The inner surface of the frame-shaped portion is in contact with the outer surface of the negative electrode layer. At least in the charged state, the outer surface of the first elastic member is in contact with the outer surface of the frame-shaped portion. Secondary battery.

2. A secondary battery according to claim 1, The frame-shaped portion is provided with an opening through which the negative electrode current collector passes. Secondary battery.

3. A secondary battery according to claim 1 or 2, The outer surface of the first elastic member is in contact with the inner surface of the frame-shaped portion, regardless of the charge / discharge state. Secondary battery.

4. A secondary battery according to claim 3, The outer surface of the first elastic member is bonded to the inner surface of the frame-shaped portion. Secondary battery.

5. A secondary battery according to claim 3, The first elastic member and the second elastic member are connected via a connecting member. Secondary battery.

6. A secondary battery according to claim 1 or 2, The frame-shaped portion completely covers the outer surface of the negative electrode layer. Secondary battery.

7. A secondary battery according to claim 1 or 2, The second elastic member further includes a bottom portion positioned to close the opening of the frame-shaped portion, The bottom portion and the frame-shaped portion are formed integrally. Secondary battery.

8. A secondary battery according to claim 1 or 2, The inner surface of the frame-shaped portion is provided with an inner projection that protrudes inward. The inner protrusion is sandwiched by the first elastic member in the stacking direction. When viewed along the stacking direction, the inner protrusion overlaps the outer periphery of the charge / discharge region. The charge / discharge region is the region where the negative electrode layer, the electrolyte layer, and the positive electrode layer overlap in the stacking direction. Secondary battery.

9. A secondary battery according to claim 1 or 2, The inner surface of the frame-shaped portion is provided with an inner projection that protrudes inward. The inner protrusion is provided in a position that surrounds the first elastic member. The thickness of the inner protrusion is equal to the thickness of the first elastic member. When viewed along the stacking direction, the inner protrusion overlaps the outer periphery of the charge / discharge region. The charge / discharge region is the region where the negative electrode layer, the electrolyte layer, and the positive electrode layer overlap in the stacking direction. Secondary battery.

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