All-solid-state battery, and method for manufacturing all-solid-state battery

Abstract

To provide an all-solid-state battery that reduces precipitation of a lithium metal during charging.SOLUTION: An all-solid-state battery 100 includes a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13 including lithium metal, and in which an insulation layer 4 is arranged so as to circulate the circumference of the positive electrode layer 11. The solid electrolyte layer 12 includes: a high ion conduction part 121 which is arranged closer to the center of the inside of the circumference of the positive electrode layer 11 and the circumference of the negative electrode layer in a plan view 13; and a low ion conduction part 122 which is arranged so as to circulate the circumference of the high ion conduction part 121, and has lower lithium ion conductivity than the high ion conduction part 121, the low ion conduction part 122 includes: an inner peripheral part 122a which is arranged closer to the center of the inside of the circumference of the positive electrode layer 11 and the circumference of the negative electrode layer 13 in a plan view; and a circumference part 122b which is arranged for the outer peripheral side of the low ion conduction part 122 with respect to the inner peripheral part 122a, and connected to the insulation layer.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a method for manufacturing an all-solid-state battery, in which an ultraviolet curable resin frame is transferred after electrode formation and attached so as to cover the outer peripheral portion of the electrode.

[0003] In Patent Document 1, the above technique suppresses short circuits and material slippage at the end portions in the plane direction of the all-solid-state battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a resin frame is transferred as in Patent Document 1, concentrated stress is generated in the outer peripheral portion of the solid electrolyte layer due to the curing shrinkage of the resin frame, resulting in a high density. For this reason, for example, the current density during charging becomes high in the outer peripheral portion, and the precipitation of lithium metal (lithium dendrite) becomes remarkable in the outer peripheral portion.

[0006] An object of the present invention is to provide an all-solid-state battery that reduces the precipitation of lithium metal during charging.

Means for Solving the Problems

[0007] The all-solid-state battery according to the present invention includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer containing lithium metal, and is an all-solid-state battery in which an insulating layer is disposed so as to surround the outer periphery of the positive electrode layer. In the all-solid-state battery of the present invention, the solid electrolyte layer includes a high ion-conducting portion disposed inside the outer periphery of the positive electrode layer and the outer periphery of the negative electrode layer in a plan view, and a low ion-conducting portion disposed so as to surround the outer periphery of the high ion-conducting portion and having a lower lithium ion conductivity than the high ion-conducting portion. The low ion-conducting portion includes an inner peripheral portion disposed inside the outer periphery of the positive electrode layer and the outer periphery of the negative electrode layer in a plan view, and an outer peripheral portion disposed on the outer peripheral side of the low ion-conducting portion with respect to the inner peripheral portion and connected to the insulating layer.

Advantages of the Invention

[0008] According to the present invention, since the low ion-conducting portion is disposed at a concentrated stress location among the regions capable of transferring lithium ions in the all-solid-state battery, precipitation of lithium metal during charging can be reduced.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0010] [First Embodiment] FIG. 1 is a cross-sectional view of an all-solid-state battery 100 according to the first embodiment. The all-solid-state battery 100 according to the first embodiment is a secondary battery capable of multiple charge and discharge cycles. The all-solid-state battery 100 is a so-called laminated type all-solid-state battery 100 that houses, in a state sealed with a laminate layer (not shown) as a battery exterior material, a plurality of the following negative electrode current collector foils 3, power generation element portions 1, and positive electrode current collector foils 2 laminated respectively inside. By making it a laminated type, the battery can be made compact and have a high capacity.

[0011] In the all-solid-state battery 100, the negative electrode current collector foils 3 and the positive electrode current collector foils 2 are alternately laminated, and a power generation element portion 1 is interposed between the negative electrode current collector foil 3 and the positive electrode current collector foil 2 adjacent to each other in the lamination direction and is formed by being pressed from the lamination direction. The power generation element portion 1 has a laminated structure including a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13.

[0012] In the power generation element portion 1 shown in FIG. 1, the power generation element portion 1 whose lower part is connected to the positive electrode current collector foil 2 and whose upper part is connected to the negative electrode current collector foil 3 is laminated in the order of the positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13 from the bottom. Also, in the power generation element portion 1 shown in FIG. 1, the power generation element portion 1 whose lower part is connected to the negative electrode current collector foil 3 and whose upper part is connected to the positive electrode current collector foil 2 is laminated in the order of the negative electrode layer 13, the solid electrolyte layer 12, and the positive electrode layer 11 from the bottom.

[0013] An insulating layer 4 is disposed so as to cover the outer periphery (side surface) of the positive electrode layer 11. Also, a gap 11a may be formed between the positive electrode layer 11 and the insulating layer 4. The gap 11a can occur when transferring a resin frame as the insulating layer 4 as in Patent Document 1 described above.

[0014] The solid electrolyte layer 12 includes a high ion conductivity portion 121 disposed at the center and a low ion conductivity portion 122 disposed so as to cover the periphery of the high ion conductivity portion 121 (see FIG. 9(c)).

[0015] In the all-solid-state battery 100 of the first embodiment, by connecting the negative electrode current collector foils 3 in parallel and connecting the positive electrode current collector foils 2 in parallel, all the power generation element portions 1 can be electrically connected in parallel. In this embodiment, the negative electrode current collector foil 3, the power generation element portion 1, and the positive electrode current collector foil 2 do not necessarily need to be stacked in multiple layers and may be in a single layer.

[0016] Note that the all-solid-state battery 100 of the first embodiment is configured in a circular or rectangular sheet shape, for example, in a state before being housed in a battery exterior material. Also, the appearance of the all-solid-state battery 100 of this embodiment and the electrical connection state (electrode structure) inside are not particularly limited.

[0017] The appearance of the all-solid-state battery 100 can be a circle, an ellipse, or a rectangular shape in a plan view. Alternatively, it may be a cylindrical shape that houses a single layer or a plurality of layers of the power generation element portions 1 wound around. Also, as the electrode structure of the all-solid-state battery 100, either a so-called non-bipolar type (internal parallel connection type) or a bipolar type (internal series connection type) may be adopted. That is, the aspects of the all-solid-state battery 100 other than the configurations described below are not particularly limited, whether known or unknown.

[0018] FIG. 2 is a cross-sectional view of the all-solid-state battery 100 of the first embodiment, where the left side of the broken line extending vertically in the figure indicates a fully discharged state, and the right side indicates a fully charged state. Here, the fully discharged state means a state where the open-circuit voltage of the all-solid-state battery 100 is equal to or lower than a predetermined lower limit voltage, and the fully charged state means a state where the open-circuit voltage of the all-solid-state battery 100 is equal to or higher than a predetermined reference voltage that is higher than the lower limit voltage.

[0019] The positive electrode current collector foil 2 is a thin plate formed of a metal such as aluminum (Al). The negative electrode current collector foil 3 is a thin plate formed of a metal such as stainless steel (SUS) or copper (Cu).

[0020] As described above, the power generation element unit 1 is interposed between the negative electrode current collector foil 3 and the positive electrode current collector foil 2 and has a laminated structure including a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13. Also, the positive electrode layer 11 and the negative electrode layer 13 are arranged so that their areas are smaller than those of the positive electrode current collector foil 2 and the negative electrode current collector foil 3 in plan view and are inside the outer perimeters of the positive electrode current collector foil 2 and the negative electrode current collector foil 3.

[0021] The positive electrode layer 11 is arranged on both main surfaces of the positive electrode current collector foil 2 (in the case of a single layer, the main surface of the positive electrode current collector foil 2 facing the negative electrode current collector foil 3). The positive electrode layer 11 is arranged so as to be within the outer shape of the negative electrode layer 13 in plan view. The positive electrode layer 11 preferably contains a positive electrode active material containing sulfur. The type of the positive electrode active material containing sulfur is not particularly limited, and examples include elemental sulfur (S), particles or thin films of organic sulfur compounds or inorganic sulfur compounds, and any material that can release lithium ions during charging and occlude lithium ions during discharging by utilizing the redox reaction of sulfur.

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

[0023] The solid electrolyte layer 12 is composed of a high ion conductivity portion 121 and a low ion conductivity portion 122. The high ion conductivity portion 121 is formed using, for example, 100[%] of the above solid electrolyte material and forms the central portion of the solid electrolyte layer 12. The high ion conductivity portion 121 has an outer shape that fits inside the outer shape of the positive electrode layer 11 in plan view.

[0024] The low ion conductivity portion 122 is a mixture of the above solid electrolyte material and an insulating material such as polytetrafluoroethylene (PTFE), and is formed such that the blending ratio is, for example, 50[%]:50[%] (the blending ratio can be arbitrarily set). The low ion conductivity portion 122 is formed in a frame shape that surrounds the outer periphery of the high ion conductivity portion 121. The lithium ion conductivity of the low ion conductivity portion 122 decreases as the blending ratio of the insulating material increases.

[0025] The low ion conductivity portion 122 has an inner peripheral portion 122a sandwiched between the positive electrode layer 11 and the negative electrode layer 13, and an outer peripheral portion 122b disposed outside the inner peripheral portion 122a (a portion disposed outside the outer shape of the positive electrode layer 11 in plan view).

[0026] The negative electrode layer 13 is disposed on both main surfaces of the negative electrode current collector foil 3 (in the case of a single layer, the surface of the negative electrode current collector foil 3 facing the positive electrode current collector foil 2). The negative electrode layer 13 is composed of a negative electrode active material containing at least lithium metal or a lithium alloy. In addition, as the material of the negative electrode layer 13, any material can be applied as long as it can occlude lithium ions during charging and release lithium ions during discharging.

[0027] The negative electrode layer 13 is disposed so as to overlap with the insulating layer 4 described later in plan view.

[0028] The insulating layer 4 is disposed in a frame shape that surrounds the outer periphery of the positive electrode layer 11. As the material of the insulating layer 4, ultraviolet curable resins such as Aronix (registered trademark) and Aron Oxetane (registered trademark) can be applied. Also, thermosetting resins can be applied as the material of the insulating layer 4, and polyethylene terephthalate (PET), epoxy resin, etc. can be applied. In addition, as the material of the insulating layer 4, Kapton (registered trademark), polypropylene (PP), polytetrafluoroethylene (PTFE), rubber (natural rubber, synthetic rubber), etc. can be applied.

[0029] As shown in the left side portion of the dashed-dotted line in FIG. 2, in the fully discharged state of the all-solid-state battery 100 of the first embodiment, for example, in a region inside the outer periphery of the positive electrode layer 11 in a plan view of the negative electrode layer 13, in a region in contact with the solid electrolyte layer 12 (high ion conductivity portion 121, low ion conductivity portion 122), lithium ions in the negative electrode layer 13 are released, pass through the solid electrolyte layer 12 (high ion conductivity portion 121, low ion conductivity portion 122), and are occluded in the positive electrode layer 11.

[0030] Therefore, the region where lithium ions are released from the negative electrode layer 13 becomes the gap 131, and the thickness of the negative electrode layer 13 decreases by the amount that becomes the gap 131. Here, the width in the thickness direction of the gap 131 facing the low ion conductivity portion 122 is narrower than the width in the thickness direction of the gap 131 facing the high ion conductivity portion 121. This is because the lithium ion conductivity is lower in the low ion conductivity portion 122 than in the high ion conductivity portion 121.

[0031] On the other hand, the all-solid-state battery 100 of the first embodiment is pressed from the thickness direction. For this reason, actually, the gap 131 disappears and the negative electrode layer 13 and the negative electrode current collector foil 3 are deformed toward the solid electrolyte layer 12 side, but in the figure, for convenience, it is illustrated in a state where the gap 131 is formed. Thus, since the gap 131 actually disappears, the contact between the surface of the negative electrode layer 13 and the solid electrolyte layer 12 is maintained, and the electrical connection between the negative electrode layer 13 and the solid electrolyte layer 12 is also maintained.

[0032] As described above, the all-solid-state battery 100 of the first embodiment is pressed from the thickness direction. For this reason, in the solid electrolyte layer 12, concentrated stress is applied to positions overlapping the outer periphery of the positive electrode layer 11 in a plan view, positions overlapping the inner periphery of the insulating layer 4 in a plan view, and positions overlapping the outer periphery of the negative electrode layer 13, respectively.

[0033] And the density of the material of the solid electrolyte layer 12 (and the current density during charge and discharge) at the portion where the concentrated stress is applied increases, and the amount of lithium ion transfer also increases.

[0034] Therefore, in the region of the solid electrolyte layer 12 that is receiving the above-described concentrated stress from the negative electrode layer 13 and where the amount of lithium ion transfer is not zero, lithium metal is likely to precipitate.

[0035] On the other hand, when the all-solid-state battery 100 in the fully discharged state is charged, the lithium ions occluded in the positive electrode layer 11 pass through the solid electrolyte layer 12 and are occluded in the gaps 131 of the negative electrode layer 13, and the gaps 131 disappear.

[0036] [Amount of lithium metal precipitation in the all-solid-state battery 1001 of the comparative example] FIG. 3 is a diagram for explaining the all-solid-state battery 1001 of the comparative example, where FIG. 3(a) is a cross-sectional view in the fully charged state, FIG. 3(b) is a distribution of lithium ion conductivity, FIG. 3(c) is a distribution of the amount of lithium ion transfer, FIG. 3(d) is a distribution of concentrated stress, and FIG. 3(e) is a distribution of the product of the amount of lithium ion transfer and concentrated stress, respectively.

[0037] As shown in FIG. 3(a), in the all-solid-state battery 1001 of the first comparative example, compared with the all-solid-state battery 100 of the first embodiment, the solid electrolyte layer 12 has the same outer shape but does not include the low ion conductivity portion 122 and is composed only of the high ion conductivity portion 121.

[0038] As shown in FIG. 3(b), the lithium ion conductivity of the solid electrolyte layer 12 is substantially uniform from the central portion (in the figure, the illustration of the distribution of lithium ion conductivity near the central portion of the solid electrolyte layer 12 is omitted, and the same applies hereinafter) to the outer periphery. In the figure, the conductivity is set to "1".

[0039] Examine the amount of lithium ion transfer in the all-solid-state battery 1001. Here, the region where the positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13 overlap in plan view is from the central portion of the positive electrode layer 11 to the position overlapping the outer periphery of the positive electrode layer 11.

[0040] Therefore, as shown in Fig. 3(c), the amount of lithium ion transfer as seen from the positive electrode current collector foil 2 is constant from the central part of the positive electrode layer 11 to the position overlapping with the outer periphery of the positive electrode layer 11 (the amount of lithium ion transfer is set to "1" in the figure), and becomes zero on the outer peripheral side thereof.

[0041] On the other hand, the amount of lithium ion transfer as seen from the negative electrode current collector foil 3 is constant from the central part of the positive electrode layer 11 to the position overlapping with the outer periphery of the positive electrode layer 11 (the amount of lithium ion transfer is set to "1" in the figure), but on the outer peripheral side thereof, as shown by the broken line in Fig. 3(c), it monotonically decreases toward the outer periphery and becomes zero when reaching the outer periphery of the negative electrode layer 13. This is because the lithium ions released from the positive electrode layer 11 during charging move while passing through the solid electrolyte layer 12 and diffuse in the entire surface direction in the negative electrode layer 13. Conversely, during discharging, the lithium ions occluded in the portion outside the outer shape of the positive electrode layer 11 in the plan view of the negative electrode layer 13 reach the positive electrode layer 11 by passing through the solid electrolyte layer 12 and moving toward the inside of the outer shape of the positive electrode layer 11 in the plan view, and are occluded in the positive electrode layer 11.

[0042] As shown in Fig. 3(d), when the all-solid-state battery 1001 of the first comparative example is formed into a stack structure, the all-solid-state battery 1001 is pressed from the thickness direction, and concentrated stress (compressive stress) is generated at the position (D3, the position where concentrated stress (A) is generated) overlapping with the outer periphery of the positive electrode layer 11 in the plan view of the solid electrolyte layer 12 (high ion conductivity portion 121), the position (D4, the position where concentrated stress (B) is generated) overlapping with the inner periphery of the insulating layer 4 in the plan view of the solid electrolyte layer 12, and the position (D5, the position where concentrated stress (C) is generated) overlapping with the outer periphery of the negative electrode layer 13 in the plan view of the solid electrolyte layer 12, respectively.

[0043] Here, the concentrated stress (A), concentrated stress (B), and concentrated stress (C) each have a distribution that peaks at the position overlapping the vertical dashed line in the figure and decreases as it moves away from this position in the plane direction, converging to zero. However, since there is a gap 11a between the position (D3) where the concentrated stress (A) is received and the position (D4) where the concentrated stress (B) is received in the solid electrolyte layer 12, the portions of the distributions of the concentrated stress (A) and the concentrated stress (B) that face the gap 11a are almost zero, and accordingly, the peaks of the concentrated stress (A) and the concentrated stress (B) are higher than the concentrated stress (C).

[0044] Also, when the insulating layer 4 is formed of an ultraviolet curable resin or the like as described above, it shrinks to some extent during curing. Therefore, in the region of the solid electrolyte layer 12 that is outside the outer periphery of the positive electrode layer 11 in plan view, a stress is applied that deforms the solid electrolyte layer 12 toward the positive electrode current collector foil 2 with the position overlapping the outer periphery of the positive electrode layer 11 in plan view of the solid electrolyte layer 12 as the center, and a concentrated stress is generated at the position (D3) overlapping the outer periphery of the positive electrode layer 11 in plan view of the solid electrolyte layer 12. Thus, the peak of the concentrated stress (A) becomes higher than the peak of the concentrated stress (B) by the amount of the concentrated stress caused by the insulating layer 4. In FIG. 3(d), the peak of the concentrated stress (A) is denoted as "1".

[0045] Note that even when the gap 11a does not exist, a concentrated stress (compressive stress) associated with the shrinkage of the insulating layer 4 can be applied to the position (D3) overlapping the outer periphery of the positive electrode layer 11 in plan view of the solid electrolyte layer 12. Further, when the elastic moduli (Young's moduli) of the positive electrode layer 11 and the insulating layer 4 are different from each other, a concentrated stress (shearing stress) can occur at the position overlapping the boundary between the positive electrode layer 11 and the insulating layer 4 of the solid electrolyte layer 12 when the all-solid-state battery 1001 (all-solid-state battery 100) is in a stacked structure.

[0046] FIG. 3(e) shows the product of the lithium ion transfer amount and the concentrated stress, which is proportional to the deposition amount of lithium metal.

[0047] In the solid electrolyte layer 12, the region where the concentrated stress (A) occurs is the position overlapping the outer periphery of the positive electrode layer 11 and is the region where lithium ion transfer occurs.

[0048] The region where the concentrated stress (B) occurs is disposed slightly outside the outer periphery of the positive electrode layer 11 in plan view, and the transfer of lithium ions occurs in a slightly lower amount than in the region where the concentrated stress (A) occurs.

[0049] The region where the concentrated stress (C) occurs is located facing the insulating layer 4 and away from the outer periphery of the positive electrode layer 11 in plan view, and almost no transfer of lithium ions occurs in this region.

[0050] Therefore, in the all-solid-state battery 1001 of the comparative example shown in FIG. 3, at the position (D3) where the concentrated stress (A) occurs and the position (D4) where the concentrated stress (B) occurs in the solid electrolyte layer 12 during charging, lithium metal is deposited on the negative electrode layer 13 side of the solid electrolyte layer 12 in the thickness direction, and the deposition amount of lithium metal also distributes according to the distribution of the concentrated stress. Also, the deposition amount of lithium metal at the position (D3) is larger than the deposition amount of lithium metal at the position (D4).

[0051] Note that at the position (D3) of the solid electrolyte layer 12, the concentrated stress (1) associated with the shrinkage of the insulating layer 4 and the concentrated stress (2) caused by the pressing force from the thickness direction when the all-solid-state battery 1001 (all-solid-state battery 100) has a stacked structure overlap and occur. Here, approximately, the difference between the peak of the concentrated stress (A) and the peak of the concentrated stress (B) can be considered as the magnitude of the concentrated stress (2), and the peak of the concentrated stress (B) can be considered as the magnitude of the concentrated stress (1). Note that, in order to make the diagram of the concentrated stress easier to view, in FIG. 3 and the like, the concentrated stress (2) is set to be smaller than the concentrated stress (1), but a state where the magnitudes of both are substantially the same or a state where the magnitude relationship is reversed may also occur.

[0052] [Amount of Lithium Metal Deposited in the All-Solid-State Battery 100 of the First Embodiment] FIG. 4 is a diagram for explaining the all-solid-state battery 100 of the first embodiment. FIG. 4(a) is a cross-sectional view in a fully charged state, FIG. 4(b) is a distribution of lithium ion conductivity, FIG. 4(c) is a distribution of the amount of lithium ion transfer, FIG. 4(d) is a distribution of concentrated stress, and FIG. 4(e) is a distribution of the product of the amount of lithium ion transfer and concentrated stress, respectively.

[0053] In the all-solid-state battery 100 of the first embodiment shown in FIG. 4, as described above, the solid electrolyte layer 12 is composed of a high ion conductivity portion 121 and a low ion conductivity portion 122.

[0054] As shown in FIG. 4(b), the lithium ion conductivity of the solid electrolyte layer 12 is substantially uniform from the central portion to the outer periphery of the high ion conductivity portion 121. In the figure, the conductivity is set to "1". And at the position (D1) which is the boundary between the outer periphery of the high ion conductivity portion 121 and the inner periphery of the low ion conductivity portion 122, the lithium ion conductivity decreases stepwise and is maintained at a substantially constant value (for example, "0.5") until it reaches the outer periphery of the low ion conductivity portion 122.

[0055] As shown in FIG. 4(c), the amount of lithium ion transfer when viewed from the positive electrode current collector foil 2 is constant from the central portion of the positive electrode layer 11 to the position (D1) overlapping with the outer periphery of the high ion conductivity portion 121 (in the figure, the amount of lithium ion transfer is set to "1"), becomes, for example, "0.5" from the position (D1) to the position (D3), and becomes zero on the outer peripheral side of the position (D3).

[0056] On the other hand, the amount of lithium ion transfer when viewed from the negative electrode current collector foil 3 is constant from the central portion of the positive electrode layer 11 to the position overlapping with the outer periphery of the high ion conductivity portion 121 (in the figure, the amount of lithium ion transfer is set to "1"), becomes, for example, "0.5" from the position (D1) to the position (D3), monotonically decreases toward the outer peripheral side from the position (D2), and becomes zero at the position (D5).

[0057] As shown in FIG. 4(d), the concentrated stress applied to the all-solid-state battery 1001 of the first embodiment is the same as that in the comparative example (FIG. 3(d)).

[0058] As shown in FIG. 4(e), in the all-solid-state battery 100 of the first embodiment, the positions where lithium metal is deposited are the boundary between the inner peripheral portion 122a and the outer peripheral portion 122b of the low ion conduction portion 122, which is the position (D3) where the concentrated stress (A) occurs, and the position where the outer peripheral portion 122b overlaps the inner periphery of the insulating layer 4 in plan view, which is the position (D4) where the concentrated stress (B) occurs. However, in the all-solid-state battery 100 of the first embodiment, the lithium ion conductivity and the amount of lithium ion transfer and reception in the region where the concentrated stress occurs are lower than those in the comparative example, and are, for example, "0.5". Therefore, as shown in FIG. 4(e), the peak (solid line) of the lithium metal precipitation amount in the all-solid-state battery 100 of the first embodiment is about half of the peak compared to the comparative example shown by the broken line in FIG. 4(e), and the lithium metal precipitation amount in the all-solid-state battery 100 of the first embodiment is reduced compared to the comparative example.

[0059] [Effect of the First Embodiment] According to the all-solid-state battery 100 of the first embodiment, in the all-solid-state battery 100 including the positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13 containing lithium metal, and in which the insulating layer 4 is disposed so as to surround the outer periphery of the positive electrode layer 11, the solid electrolyte layer 12 includes a high ion conduction portion 121 disposed inside the outer periphery of the positive electrode layer 11 and the outer periphery of the negative electrode layer 13 in plan view, and a low ion conduction portion 122 disposed so as to surround the outer periphery of the high ion conduction portion 121 and having a lower lithium ion conductivity than the high ion conduction portion 121. The low ion conduction portion 122 includes an inner peripheral portion 122a disposed inside the outer periphery of the positive electrode layer 11 and the outer periphery of the negative electrode layer 13 in plan view, and an outer peripheral portion 122b disposed on the outer peripheral side of the low ion conduction portion 122 with respect to the inner peripheral portion 122a and connected to the insulating layer 4.

[0060] With the above configuration, in the low ion conductivity portion 122, concentrated stress is applied to the position that forms the boundary between the inner peripheral portion 122a and the outer peripheral portion 122b (the position (D3) that overlaps with the outer periphery of the positive electrode layer 11 in a plan view in the low ion conductivity portion 122), and the position (D4) that overlaps with the inner periphery of the insulating layer 4 in a plan view in the outer peripheral portion 122. However, the amount of lithium ion transfer in the low ion conductivity portion 122 (inner peripheral portion 122a, outer peripheral portion 122b) is lower than that in the high ion conductivity portion 121. Therefore, during charging of the all-solid-state battery 100, the precipitation amount of lithium metal at the positions (D3, D4) that receive concentrated stress can be reduced.

[0061] [Second Embodiment] FIG. 5 is a diagram for explaining the all-solid-state battery 100 of the second embodiment. FIG. 5(a) is a cross-sectional view in a fully charged state, FIG. 5(b) is a distribution of lithium ion conductivity, FIG. 5(c) is a distribution of the amount of lithium ion transfer, FIG. 5(d) is a distribution of concentrated stress, and FIG. 5(e) is a distribution of the product of the amount of lithium ion transfer and concentrated stress, respectively. In the following description, for parts common to the first embodiment, the description will be omitted unless necessary.

[0062] In the solid electrolyte layer 12 of the all-solid-state battery 100 of the second embodiment, the thickness of the low ion conductivity portion 122 is greater than the thickness of the high ion conductivity portion 121. In FIG. 5, on the positive electrode layer 11 side of the solid electrolyte layer 12, the high ion conductivity portion 121 and the low ion conductivity portion 122 form a substantially flat plane, but a step is formed on the negative electrode layer 13 side of the solid electrolyte layer 12. On the other hand, the negative electrode layer 13 is thinner by the amount that the low ion conductivity portion 122 is thicker.

[0063] The configuration shown in FIG. 5 is a case where the positive electrode layer 11 is formed of a harder material than the negative electrode layer 13, and is obtained by stacking the all-solid-state battery 100. Conversely, when the positive electrode layer 11 is formed of a harder material than the negative electrode layer 13 and the all-solid-state battery 100 is in a stacked structure, a step is formed on the positive electrode layer 11 side of the solid electrolyte layer 12.

[0064] That is, in the second embodiment, with the thicknesses of the positive electrode layer 11, the solid electrolyte layer 12 (high ion conductivity portion 121, low ion conductivity portion 122), and the negative electrode layer 13 being constant (or substantially constant), the thickness of the low ion conductivity portion 122 is made greater than the thickness of the high ion conductivity portion 121, and accordingly, the thicknesses of the portions of the positive electrode layer 11 and / or the negative electrode layer 13 that overlap with the low ion conductivity portion 122 are made smaller.

[0065] In the second embodiment, since the thickness of the low ion conductivity portion 122 is greater than that in the first embodiment, the length of the path through the region with low lithium ion conductivity in the thickness direction becomes longer. Therefore, as shown in FIG. 5(c), between position (D3) and position (D5), the amount of ion transfer is lower than that in the first embodiment (shown by the dashed line).

[0066] Note that the lithium ion conductivity of the low ion conductivity portion 122 in the second embodiment (FIG. 5(b)) is the same as that in the first embodiment (FIG. 4(b)), and the concentrated stress applied to the all-solid-state battery 100 in the second embodiment (FIG. 5(d)) is the same as that in the first embodiment.

[0067] Therefore, as shown in FIG. 5(e), the product of the amount of lithium ion transfer and the concentrated stress, that is, the amount of lithium metal precipitation, is less than that in the first embodiment shown by the dashed line.

[0068] As described above, in the second embodiment, the thickness of the low ion conductivity portion 122 is greater than the thickness of the high ion conductivity portion 121. As a result, the length of the path through the region with low lithium ion conductivity in the thickness direction becomes longer, so that the amount of lithium ion transfer can be reduced accordingly, and the precipitation of lithium metal can be further reduced.

[0069] [Third Embodiment] FIG. 6 is a diagram for explaining the all-solid-state battery 100 of the third embodiment, where FIG. 6(a) is a cross-sectional view in a fully charged state, FIG. 6(b) is a distribution of lithium ion conductivity, FIG. 6(c) is a distribution of the amount of lithium ion transfer, FIG. 6(d) is a distribution of concentrated stress, and FIG. 6(e) is a distribution of the product of the amount of lithium ion transfer and the concentrated stress, respectively.

[0070] As shown in FIG. 6(b), in all-solid-state battery 100 of the third embodiment, the lithium ion conductivity of low ion conductivity portion 122 is configured to monotonically decrease toward the outer peripheral side. That is, in low ion conductivity portion 122, the blending ratio of the solid electrolyte material to the insulating material monotonically decreases toward the outer periphery, and conversely, the blending ratio of the insulating material to the solid electrolyte material monotonically increases toward the outer periphery.

[0071] For example, from position (D1) to position (D3) (inner peripheral portion 122a), the blending ratio of the solid electrolyte material is decreased at a predetermined first slope, from position (D3) to position (D5), the blending ratio of the solid electrolyte material is decreased at a second slope smaller than the first slope, and on the outer peripheral side of position (D5), the blending ratio is continuously and monotonically decreased so as to be constant. In FIG. 6, the blending ratio of the solid electrolyte material continuously and monotonically decreases, but it may be monotonically decreased stepwise.

[0072] Then, the lithium ion conductivity of solid electrolyte layer 12 (low ion conductivity portion 122) changes in proportion to the blending ratio of the solid electrolyte material.

[0073] As shown in FIG. 6(c), when looking from the positive electrode current collector foil 2 side, the lithium ion conductivity is constant from the central portion of solid electrolyte layer 12 to position (D1) (for example, the conductivity is "1"), but monotonically linearly decreases from position (D1) to position (D3), becomes, for example, "0.5" at position (D3), and when exceeding position (D3), decreases stepwise to zero. Also, when looking from the negative electrode current collector foil 3 side, the lithium ion conductivity is constant from the central portion of solid electrolyte layer 12 to position (D1) (for example, the conductivity is "1"), but monotonically linearly decreases from position (D1) to position (D3), becomes, for example, "0.5" at position (D3), and when exceeding position (D3), monotonically decreases curvilinearly and becomes zero when reaching position (D5).

[0074] The concentrated stress shown in Fig. 6(d) and the product of the amount of lithium ion transfer shown in Fig. 6(e) and the concentrated stress are the same as those in the first embodiment. However, the amount of lithium ion transfer from the position (D1), which is the boundary between the high ion conductivity portion 121 and the low ion conductivity portion 122, to the position (D3) where the peak of the concentrated stress (A) occurs is larger than that in the first embodiment.

[0075] According to the third embodiment, the low ion conductivity portion 122 is a mixture of the material (solid electrolyte material) of the high ion conductivity portion 121 and an insulating material, and the mixing ratio of the material (solid electrolyte material) of the high ion conductivity portion 121 with respect to the insulating material is arranged to monotonically decrease toward the outer periphery of the low ion conductivity portion 122. Thereby, precipitation of lithium metal at the position (D3) overlapping the outer periphery of the positive electrode layer 11 in the plan view of the solid electrolyte layer 12 and at the position (D4) overlapping the inner periphery of the insulating layer 4 in the plan view of the solid electrolyte layer 12 can be reduced. In particular, as shown in Fig. 6(b), when the mixing ratio of the solid electrolyte material continuously changes at the position (D1) which is the boundary between the high ion conductivity portion 121 and the low ion conductivity portion 122, the amount of lithium ion transfer is larger than when the mixing ratio is changed discontinuously in a step function, and thus the capacity of the all-solid-state battery 100 can be increased accordingly.

[0076] [Fourth Embodiment] Fig. 7 is a diagram for explaining the all-solid-state battery 100 of the fourth embodiment, where Fig. 7(a) is a cross-sectional view in a fully charged state, Fig. 7(b) is a distribution of lithium ion conductivity, Fig. 7(c) is a distribution of the amount of lithium ion transfer, Fig. 7(d) is a distribution of concentrated stress, and Fig. 7(e) is a distribution of the product of the amount of lithium ion transfer and the concentrated stress, respectively.

[0077] In the all-solid-state battery 100 of the fourth embodiment, the area of the negative electrode layer 13 in contact with the solid electrolyte layer 12 is larger than the area in contact with the negative electrode current collector foil 3, and the side surface of the negative electrode layer 13 is an inclined surface 132 inclined toward the negative electrode current collector foil 3 side. Note that the low ion conductivity portion 122 of the fourth embodiment is the same as that of the first embodiment.

[0078] The position (D2) of the edge in contact with the negative current collector foil 3 on the inclined surface 132 is disposed closer to the central portion side of the solid electrolyte layer 12 than the position (D3) where the outer periphery of the positive electrode layer 11 overlaps in plan view of the low ion conductivity portion 122 and the position (D4) where the inner periphery of the insulating layer 4 overlaps in plan view of the low ion conductivity portion 122.

[0079] The position (D5) of the edge in contact with the solid electrolyte layer 12 on the inclined surface 132 is disposed closer to the outer periphery side of the solid electrolyte layer 12 than the position (D3) where the outer periphery of the positive electrode layer 11 overlaps in plan view of the low ion conductivity portion 122 and the position (D4) where the inner periphery of the insulating layer 4 overlaps in plan view of the low ion conductivity portion 122.

[0080] Therefore, the positions (D3) and (D4) overlap the inclined surface 132 in plan view, and the inclined surface 132 is separated from the negative current collector foil 3 at the position overlapping the positions (D3) and (D4) in plan view. For this reason, in the solid electrolyte layer 12, at the position (D3) where the outer periphery of the positive electrode layer 11 overlaps in plan view and the position (D4) where the inner periphery of the insulating layer 4 overlaps in plan view, no concentrated stress is generated due to the pressing force generated when the all-solid-state battery 100 is in a stacked structure.

[0081] As shown in FIG. 7(c), when viewed from the positive current collector foil 2 side, the amount of lithium ion transfer and reception is substantially constant (for example, the conductivity is set to "1") from the central portion of the solid electrolyte layer 12 (high ion conductivity portion 121) to the position (D1) that is the boundary between the high ion conductivity portion 121 and the low ion conductivity portion 122. Further, from the position (D1) to the position (D2) of the edge in contact with the negative current collector foil 3 on the inclined surface 132, it changes constantly according to the lithium ion conductivity (for example, "0.5") of the low ion conductivity portion 122.

[0082] On the outer peripheral side of the position (D2), the negative electrode current collector foil 3 and the negative electrode layer 13 are separated. However, as described above, the lithium ions occluded in the negative electrode layer 13 diffuse in the plane direction within the outer shape range of the positive electrode layer 11 while passing through the solid electrolyte layer 12. Therefore, on the outer peripheral side of the position (D2), the amount of lithium ion transfer does not immediately become zero, but monotonically decreases toward the outer peripheral side, and monotonically decreases until the position (D3) that overlaps with the outer periphery of the positive electrode layer 11 in the plan view of the solid electrolyte layer 12, and becomes zero when exceeding the position (D3). On the other hand, when viewed from the negative electrode current collector foil 3, the amount of lithium ion transfer changes in the same manner as above from the central portion of the solid electrolyte layer 12 (high ion conductivity portion 121) to the position (D2), but becomes zero when exceeding the position (D2) as shown by the broken line.

[0083] As shown in FIG. 7(d), in the solid electrolyte layer 12 (low ion conductivity portion 122), a concentrated stress (D) is generated at the position (D2) that overlaps with the edge in contact with the negative electrode current collector foil 3 of the inclined surface 132 in the plan view, and a concentrated stress (E) is generated at the position (D3) that overlaps with the outer periphery of the positive electrode layer 11 in the plan view.

[0084] The concentrated stress (D) is generated due to the pressing force applied from the thickness direction when the all-solid-state battery 100 has a stack structure. However, the pressing force received by the edge in contact with the negative electrode current collector foil 3 of the inclined surface 132 is diffused to the central portion side and the outer peripheral side in the negative electrode layer 13. Therefore, the concentrated stress (D) diffuses based on the degree of diffusion of the pressing force, and the peak becomes smaller accordingly.

[0085] The concentrated stress (E) is generated due to the shrinkage of the insulating layer 4.

[0086] As shown in FIG. 7(e), the product of the amount of lithium ion transfer and the concentrated stress, that is, the precipitation of lithium metal, occurs according to the distribution of the concentrated stress in FIG. 7(d). However, since both the concentrated stress (D) and the concentrated stress (E) are generated in the low ion conductivity portion 122, the amount of precipitation of lithium metal can be suppressed.

[0087] According to the fourth embodiment, the negative electrode layer 13 is sandwiched between the solid electrolyte layer 12 and the negative electrode current collector foil 3, and the area of the main surface of the negative electrode layer 13 that contacts the solid electrolyte layer 12 is larger than the area of the main surface of the negative electrode layer 13 that contacts the negative electrode current collector foil 3.

[0088] As a result, an inclined surface 132 inclined toward the negative electrode current collector foil 3 side is formed in the negative electrode layer 13. When the all-solid-state battery 100 of the fourth embodiment is pressed in the thickness direction, the edge of the inclined surface 132 that contacts the negative electrode current collector foil 3 receives the pressing force. Since the pressing force is dispersed to the inner peripheral side and the outer peripheral side of the negative electrode layer 13, the concentrated stress received by the solid electrolyte layer 12 is also dispersed according to the degree of dispersion of the pressing force, and accordingly, the peak of the concentrated stress also decreases. Therefore, the precipitation of lithium metal due to the concentrated stress can be suppressed.

[0089] [Fifth Embodiment] FIG. 8 is a diagram for explaining the all-solid-state battery 100 of the fifth embodiment. FIG. 8(a) is a cross-sectional view in a fully charged state, FIG. 8(b) is a distribution of lithium ion conductivity, FIG. 8(c) is a distribution of the amount of lithium ion transfer, FIG. 8(d) is a distribution of concentrated stress, and FIG. 8(e) is a distribution of the product of the amount of lithium ion transfer and concentrated stress, respectively.

[0090] The structure of the all-solid-state battery 100 of the fifth embodiment (FIG. 8(a)) is the same as that of the first embodiment. The low ion conductivity portion 122 is a mixture of the material (solid electrolyte material) of the high ion conductivity portion 121 and an insulating material. Also, the mixing ratio of the solid electrolyte material to the insulating material in the high ion conductivity portion 121 and the low ion conductivity portion 122 is the same as that of the first embodiment.

[0091] Therefore, the lithium ion conductivity shown in FIG. 8(b) and the amount of lithium ion transfer shown in FIG. 8(c) are the same as those of the first embodiment.

[0092] However, as the insulating material, a material having a lower elastic modulus and a higher elastic limit than the material (solid electrolyte material) of the high ion conduction portion 121, for example, an organic polymer material such as rubber, is applied. As the rubber, natural rubber or synthetic rubber can be applied. As the natural rubber, for example, a substance mainly composed of cis-polyisoprene and produced by addition polymerization in vivo can be applied. As the synthetic rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene rubber, ethylene-propylene rubber, chlorosulfonated polyethylene rubber, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, silicone rubber, etc. can be applied.

[0093] In the all-solid-state battery 100 of the fifth embodiment, concentrated stress is generated at the same position as in the first embodiment. However, the insulating material constituting the low ion conduction portion 122 is an organic polymer material such as rubber, and the rubber elasticity (stretchability) is high. Therefore, the concentrated stress received by the low ion conduction portion 122 is diffused to the central side and the outer peripheral side of the solid electrolyte layer 12, and the peak of the concentrated stress is reduced accordingly.

[0094] Therefore, as shown in FIG. 7(e), the product of the lithium ion transfer amount and the concentrated stress, that is, the precipitation of lithium metal, has a wider base and is more widely distributed than the concentrated stress in the first embodiment shown by the broken line, but the peak is smaller accordingly. Therefore, the precipitation amount of lithium metal at the concentrated stress generation location can be reduced.

[0095] On the other hand, it is also preferable to set the low ion conduction portion 122 to have a higher elastic modulus than the high ion conduction portion 121. As the insulating material constituting the low ion conduction portion 122, for example, a material having a high elastic modulus such as ceramics is suitable. As the ceramics, for example, cermet, silicon carbide, alumina, aluminum nitride, silicon nitride, mullite, zirconia, etc. can be applied. In this case, since the stress strain generated in the low ion conduction portion 122 becomes small, the concentrated stress in the low ion conduction portion 122 can be reduced accordingly, and the precipitation of lithium metal due to the concentrated stress can be reduced.

[0096] [Sixth Embodiment] FIG. 9 is a diagram showing the manufacturing process of the all-solid-state battery 100 according to the sixth embodiment. FIG. 9(a) is a cross-sectional view of the solid electrolyte layer 12 before press molding, FIG. 9(b) is a cross-sectional view of the solid electrolyte layer 12 after press molding, FIG. 9(c) is a plan view of the solid electrolyte layer 12 after press molding, and FIG. 9(d) is a cross-sectional view of a modified example of the solid electrolyte layer 12 after press molding. FIG. 10 is a diagram showing the manufacturing process of the all-solid-state battery 100 according to the sixth embodiment. FIG. 10(e) is a cross-sectional view in which the positive electrode current collector foil 2, the positive electrode layer 11, the solid electrolyte layer 12, the negative electrode layer 13, and the negative electrode current collector foil 3 are laminated in this order, and FIG. 10(f) is a cross-sectional view after covering the periphery of the positive electrode layer 11 with an insulating material.

[0097] In the all-solid-state battery 100 according to the sixth embodiment, an intermediate region 123 (FIGS. 9(b) and 10) is formed between the high ion-conducting portion 121 and the low ion-conducting portion 122 in the solid electrolyte layer 12. Also, in the sixth embodiment, the manufacturing process of the all-solid-state battery 100 will be described, but it can also be applied to other embodiments.

[0098] As shown in FIG. 9(a), a first member 121c having a rectangular (circular may also be acceptable) shape formed of a solid electrolyte material, and a frame-shaped second member 122c which is a mixture of a solid electrolyte material and an insulating material (for example, fibrous filler such as PTFE) and has an opening 122d slightly smaller than the outer shape of the first member 121c are prepared.

[0099] As shown in FIG. 9(b), the first member 121c and the second member 122c are brought into contact with each other such that the opening 122d of the second member 122c is inside the outer shape of the first member 121c in a plan view, and the solid electrolyte layer 12 is formed by further press molding (dry process) from the thickness direction. At this time, the portions where the first member 121c and the second member 122c overlap each other in a plan view are fused to form the intermediate region 123.

[0100] As shown in FIG. 9(c), the intermediate region 123 is arranged so as to surround the high ion-conducting portion 121 between the high ion-conducting portion 121 and the low ion-conducting portion 122.

[0101] Here, the first member 121c may be blended with the same insulating material as that contained in the second member 122c at a certain blending ratio (for example, solid electrolyte material: insulating material = 99 [%]: 1 [%]). Thereby, the materials constituting the first member 121c and the second member 122c can be efficiently diffused in the intermediate region 123, and the compositional unevenness in the intermediate region 123 can be reduced.

[0102] Also, as shown in FIG. 9(d), by appropriately setting conditions such as press molding conditions, the intermediate region 123 may be formed in a state where the first member 121c and the second member 122c are not mixed with each other.

[0103] As shown in FIG. 10(e), the positive current collector foil 2, the positive electrode layer 11, the solid electrolyte layer 12, the negative electrode layer 13, and the negative current collector foil 3 are laminated in this order. At this time, the high ion conductivity portion 121 (and the intermediate region 123) is disposed inside the outer shape of the positive electrode layer 11 in plan view, and the positive electrode layer 11 is disposed inside the outer shape of the negative electrode layer 13 in plan view. Note that the power generation element portion 1 is formed by the positive electrode layer 11, the solid electrolyte layer 12, and the negative electrode layer 13.

[0104] As shown in FIG. 10(d), for example, an ultraviolet curable insulating material is transferred to the region surrounded by the positive current collector foil 2, the side surface of the positive electrode layer 11, and the solid electrolyte layer 12 (low ion conductivity portion 122), and the insulating layer 4 is formed by irradiating ultraviolet rays to solidify the insulating material. This step is preferably performed in a manner of forming the structure shown in FIG. 10(e) into a stack structure following the stack structure shown in FIG. 1 and transferring the insulating material to the outer peripheries of all the positive electrode layers 11 at the same time. Note that a gap 11a may be formed between the positive electrode layer 11 and the insulating layer 4.

[0105] According to the manufacturing method of the all-solid-state battery 100 of the sixth embodiment, it includes a positive electrode layer 11, a solid electrolyte layer 12, and a negative electrode layer 13 containing lithium metal, and is a manufacturing method of the all-solid-state battery 100 in which an insulating layer 4 is disposed so as to surround the outer periphery of the positive electrode layer 11. A first member 121c having an outer shape smaller than that of the positive electrode layer 11 and containing a solid electrolyte material is formed, and a frame-shaped second member 122c which is a mixture of a solid electrolyte material and an insulating material and has an opening 122d smaller than the outer shape of the first member 121c is formed. The solid electrolyte layer 12 is formed by bringing the first member 121c and the second member 122c into contact with each other so that the first member 121c covers the opening 122d and pressing the first member 121c and the second member 122c from the thickness direction. The solid electrolyte layer 12 is sandwiched between the positive electrode layer 11 and the negative electrode layer 13 in a manner that the first member 121c is disposed inside the outer shapes of the positive electrode layer 11 and the negative electrode layer 13 in plan view, and the outer periphery of the positive electrode layer 11 and the outer periphery of the solid electrolyte layer 12 are covered with an insulating material that becomes the material of the insulating layer 4.

[0106] By the above method, concentrated stress due to shrinkage of the insulating layer 4 occurs at least at a position overlapping the outer periphery of the positive electrode layer 11 in plan view of the solid electrolyte layer 12. The position where the concentrated stress occurs is the second member 122c (low ion conductivity portion 122) of the solid electrolyte layer 12, where the lithium ion conductivity is lower than that of the first member 121c (high ion conductivity portion 121). Therefore, the amount of lithium ion transfer at the position where the concentrated stress occurs can be set low, and thereby precipitation of lithium metal at the location where the concentrated stress occurs can be reduced.

[0107] The embodiments of the present invention have been described above. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. Also, the above embodiments can be combined as appropriate.

Explanation of reference numerals

[0108] 100 All-solid-state battery, 1 power generation element unit, 11 positive electrode layer, 12 solid electrolyte layer, 121 high ion conduction part, 122 low ion conduction part, 122a inner peripheral part, 122b outer peripheral part, 13 negative electrode layer, 2 positive electrode current collector foil, 3 negative electrode current collector foil, 4 insulating layer

Claims

1. In an all-solid-state battery including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer containing a lithium metal, wherein an insulating layer is disposed so as to surround the outer periphery of the positive electrode layer, the solid electrolyte layer includes: a high ion conductivity portion disposed inside the outer peripheries of the positive electrode layer and the negative electrode layer in a plan view; a low ion conductivity portion disposed so as to surround the outer periphery of the high ion conductivity portion and having a lower lithium ion conductivity than the high ion conductivity portion; the low ion conductivity portion includes: an inner peripheral portion disposed inside the outer peripheries of the positive electrode layer and the negative electrode layer in a plan view; an outer peripheral portion disposed on the outer peripheral side of the low ion conductivity portion with respect to the inner peripheral portion and connected to the insulating layer, the all-solid-state battery.

2. The all-solid-state battery according to claim 1, wherein the thickness of the low ion conductivity portion is thicker than the thickness of the high ion conductivity portion.

3. The all-solid-state battery according to claim 1 or claim 2, wherein the low ion conductivity portion is a mixture of the material of the high ion conductivity portion and an insulating material, and the blending ratio of the material of the high ion conductivity portion with respect to the insulating material is monotonically decreased toward the outer periphery of the low ion conductivity portion.

4. The all-solid-state battery according to claim 1 or claim 2, wherein the low ion conductivity portion is a mixture of the material of the high ion conductivity portion and an insulating material, and the insulating material has a lower elastic modulus and a higher elastic limit than the material of the high ion conductivity portion.

5. The all-solid-state battery according to claim 4, wherein the insulating material is an organic polymer material.

6. The all-solid-state battery according to claim 1 or claim 2, wherein the low ion conductivity portion is formed of a material having an elastic modulus equal to or higher than the elastic modulus of the high ion conductivity portion.

7. The negative electrode layer is sandwiched between the solid electrolyte layer and a negative electrode current collector foil, The all-solid-state battery according to any one of claims 1 to 6, wherein the area of the main surface of the negative electrode layer in contact with the solid electrolyte layer is larger than the area of the main surface of the negative electrode layer in contact with the negative electrode current collector foil.

8. A method for manufacturing an all-solid-state battery including a positive electrode layer, a solid electrolyte layer, and a negative electrode layer containing a lithium metal, wherein an insulating layer is disposed so as to surround the outer periphery of the positive electrode layer, the method comprising: forming a first member including a solid electrolyte material and having an outer shape smaller than the outer shape of the positive electrode layer; forming a second member having a frame shape, which is a mixture of the solid electrolyte material and an insulating material and has an opening smaller than the outer shape of the first member; The first member and the second member are brought into contact with each other so that the first member covers the opening portion, and the solid electrolyte layer is formed by pressing the first member and the second member from the thickness direction. The solid electrolyte layer is sandwiched between the positive electrode layer and the negative electrode layer in a manner such that the first member is disposed inside the outer shapes of the positive electrode layer and the negative electrode layer in a plan view. A method for manufacturing an all-solid-state battery that covers the outer periphery of the positive electrode layer with an insulating material that becomes a material of the insulating layer.

Images