JP2022062572A - All-solid battery - Google Patents

Abstract

To suppress the occurrence of a crack of a solid electrolyte that causes short-circuiting.SOLUTION: An all-solid battery includes a solid electrolyte layer, a negative electrode layer including a negative electrode lithium metal layer stacked on one surface of the solid electrolyte layer and having lithium metal precipitated, and a positive electrode layer stacked on the other surface of the solid electrolyte layer. The solid electrolyte layer includes an electrolyte base part that forms a surface region held between the negative electrode layer and the positive electrode layer, and an outer edge part provided along the outer periphery of the electrolyte base part and extending on the outer side relative to the negative electrode lithium metal layer. In the outer edge part of the solid electrolyte layer, a surface facing the negative electrode layer is flush with or concave with respect to the electrolyte base part and is formed to protrude to the positive electrode layer side.SELECTED DRAWING: Figure 1

Description

The present invention relates to an all-solid-state battery.

Patent Document 1 proposes an all-solid-state battery in which the end portion of the electrolyte layer is formed in a convex shape protruding toward the negative electrode layer to thicken the end portion of the electrolyte layer and improve its strength.

Patent No. 6608188

In recent years, from the viewpoint of improving the energy density, an all-solid-state battery using metallic lithium for the negative electrode has been developed. In this type of all-solid-state battery, metallic lithium precipitates on the negative electrode during charging to form a negative electrode metallic lithium layer. On the other hand, at the time of discharge, at least a part of the negative electrode metal lithium layer disappears due to the movement of lithium ions to the positive electrode.

In an all-solid-state battery having such a configuration, metallic lithium precipitates so as to stretch toward the outside of the solid electrolyte, and the stretching may cause stress concentration at the contact portion between the negative metal lithium layer and the solid electrolyte. be. In particular, in the structure of the all-solid-state battery proposed in Patent Document 1, the end portion of the electrolyte layer comes into contact with the end face of the negative electrode. Therefore, when the structure is applied to an all-solid-state battery using metallic lithium as the negative electrode, stress concentration occurs between the end face of the negative electrode and the end of the electrolyte layer due to the stretching of the negative electrode lithium metal, which causes a short circuit. May cause cracks in the electrolyte.

Therefore, the present invention is to provide an all-solid-state battery capable of suppressing the occurrence of cracks in the solid electrolyte layer, which causes a short circuit.

According to an aspect of the present invention, the solid electrolyte layer is laminated on one surface of the solid electrolyte layer, the negative electrode layer including the negative electrode lithium metal layer in which metallic lithium is deposited, and the other surface of the solid electrolyte layer are laminated. An all-solid-state battery including a positive electrode layer is provided. In this all-solid-state battery, the solid electrolyte layer has an electrolyte base portion constituting a surface region sandwiched between the negative electrode layer and the positive electrode layer, and an outer edge provided on the outer periphery of the electrolyte base portion and extending outward from the negative electrode lithium metal layer. With a part. The outer edge of the solid electrolyte layer is configured such that the surface facing the negative electrode layer is flush with or concave with respect to the electrolyte base and protrudes toward the positive electrode layer.

According to the present invention, it is possible to suppress the occurrence of cracks in the solid electrolyte layer, which causes a short circuit.

FIG. 1 is a diagram illustrating a configuration of an all-solid-state battery according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of an all-solid-state battery according to the second embodiment. FIG. 3 is a diagram illustrating a configuration of an all-solid-state battery according to the third embodiment. FIG. 4 is a diagram illustrating a configuration of an all-solid-state battery according to the fourth embodiment. FIG. 5 is a diagram illustrating a configuration of an all-solid-state battery according to the fifth embodiment.

Hereinafter, each embodiment of the present invention will be described.

(First Embodiment)
The all-solid-state battery 10 according to the first embodiment of the present invention will be described.

FIG. 1 is a diagram illustrating the configuration of the all-solid-state battery 10 of the present embodiment. In particular, FIG. 1A shows a schematic configuration of the all-solid-state battery 10 in the state of precipitation of metallic lithium (during charging), and FIG. 1B shows the all-solid-state battery 10 in the state of disappearing metallic lithium (during discharging). The schematic configuration of is shown. In addition, in FIG. 1, for simplification of the drawing, only the main part (a part of the outer peripheral region of each layer) to which the configuration of this embodiment is applied is shown.

The all-solid-state battery 10 is configured by sealing the cell unit 10A, which is formed by laminating one or more laminated bodies in which the solid electrolyte layer 15 is laminated between the negative electrode layer n and the positive electrode layer p, with the laminating material 20. Will be done. Note that FIG. 1 shows an example in which the cell unit 10A is composed of one laminated body for the sake of simplification of the drawing. The cell unit 10A is provided with electrical wiring (positive electrode lead, negative electrode lead, positive electrode current collector plate, negative electrode current collector plate, etc.) for connecting to an external electric load of the laminated material 20. ..

The cell unit 10A of the present embodiment is formed in a substantially rectangular shape in a plan view. That is, the negative electrode layer n, the positive electrode layer p, and the solid electrolyte layer 15 are each formed in a substantially rectangular shape in a plan view.

The negative electrode layer n is mainly a negative electrode lithium metal layer 14 laminated on the other surface (upper surface in the drawing) in the stacking direction with respect to the solid electrolyte layer 15, and a negative electrode current collector connected to the negative electrode lithium metal layer 14. It is composed of a body 12.

The negative electrode lithium metal layer 14 is mainly composed of lithium metal and functions as a negative electrode active material. In particular, as shown in FIG. 1A, the negative electrode lithium metal layer 14 is a region metal between the solid electrolyte layer 15 and the negative electrode current collector 12 (particularly, a portion facing the positive electrode active material layer 17) during charging. It is formed by the precipitation of lithium. On the other hand, as shown in FIG. 1 (b), at least a part of the metallic lithium constituting the negative electrode lithium metal layer 14 becomes lithium ions and disappears at the time of discharge. Therefore, the thickness of the negative electrode lithium metal layer 14 at the time of discharging is reduced as compared with that at the time of charging.

In particular, in the present embodiment, the negative electrode lithium metal layer 14 is configured such that the negative electrode outer edge portion 14A constituting the outer peripheral portion in the lateral direction thereof is accommodated inside the electrolyte outer edge portion 15B. In the present embodiment, the negative electrode outer edge portion 14A means a region along the outer periphery of the substantially rectangular negative electrode lithium metal layer 14 and facing the electrolyte outer edge portion 15B in the stacking direction.

Here, the precipitation of metallic lithium basically occurs in the region between the solid electrolyte layer 15 and the negative electrode current collector 12 facing the positive electrode active material layer 17. On the other hand, from the viewpoint of more reliably suppressing the precipitation of metallic lithium outside the positive electrode active material layer 17 on the solid electrolyte layer 15 (particularly on the outer edge portion 15B of the electrolyte), the maximum discharge region of the all-solid-state battery 10 is set. It is preferable to limit the thickness to the extent that the negative electrode lithium metal layer 14 does not completely disappear. As a result, a part of the negative electrode lithium metal layer 14 remains without disappearing at the time of discharge (see FIG. 1 (b)), so that the precipitation region of metallic lithium is suitably adjusted to the portion of the negative electrode lithium metal layer 14. Can be done.

Further, instead of or in addition to the above-mentioned method for adjusting the precipitation region of metallic lithium, a layer having a higher affinity for metallic lithium than the solid electrolyte layer 15 may be provided between the solid electrolyte layer 15 and the negative electrode current collector 12. good. In particular, by providing such a layer, the precipitation region of metallic lithium can be suitably adjusted without limiting the maximum discharge region (even if the configuration is such that the negative electrode lithium metal layer 14 is completely eliminated). can.

The positive electrode layer p is mainly a positive electrode active material layer 17 laminated on one surface (lower surface in the figure) in the stacking direction with respect to the solid electrolyte layer 15, and a positive electrode current collector connected to the positive electrode active material layer 17. It is composed of a body 18. In particular, in the present embodiment, the surface of the positive electrode active material layer 17 on the side of the solid electrolyte layer 15 of the positive electrode outer edge portion 17A constituting the outer peripheral portion in the lateral direction is separated from the solid electrolyte layer 15 (upper and lower in the figure). It is formed in a substantially straight line shape that inclines toward (direction). In the present embodiment, the positive electrode outer edge portion 17A means a region along the outer periphery of the substantially rectangular positive electrode active material layer 17 and facing a region facing the electrolyte outer edge portion 15B, which will be described later, in the stacking direction. do.

The solid electrolyte layer 15 mainly has an electrolyte base 15A which is a basic surface region sandwiched between the negative electrode layer n and the positive electrode layer p, and the outer periphery of the electrolyte base 15A, that is, the outer periphery of the solid electrolyte layer 15 in the lateral direction. It is composed of an electrolyte outer edge portion 15B constituting the portion.

The electrolyte base 15A is a surface region of the solid electrolyte layer 15 in which one surface faces the negative electrode lithium metal layer 14 and the other surface faces the positive electrode active material layer 17. Further, the electrolyte outer edge portion 15B is a region extending outward from the electrolyte base portion 15A in the solid electrolyte layer 15.

Then, the electrolyte outer edge portion 15B of the present embodiment extends outward from the negative electrode outer edge portion 14A of the negative electrode lithium metal layer 14. That is, the electrolyte base portion 15A envelops the negative electrode outer edge portion 14A in a plan view. In other words, the surface region of the negative electrode lithium metal layer 14 is contained in the surface region of the solid electrolyte layer 15.

Further, the surface of the outer edge portion 15B of the electrolyte on the negative electrode layer n side is continuous with the electrolyte base portion 15A and is flush with the surface thereof. As a result, the electrolyte outer edge portion 15B has a structure in which the electrolyte outer edge portion 15B is completely separated from the negative electrode outer edge portion 14A in a side view without overlapping. On the other hand, in the electrolyte outer edge portion 15B of the solid electrolyte layer 15, the surface on the positive electrode layer p side has a structure in which the surface on the positive electrode layer p side protrudes from the electrolyte base portion 15A. As a result, the electrolyte outer edge portion 15B is thicker than the electrolyte base portion 15A. In particular, in the present embodiment, the electrolyte outer edge portion 15B projects toward the positive electrode layer p side in the entire lateral region extending from the electrolyte base portion 15A to the outside of the negative electrode lithium metal layer 14. Therefore, the electrolyte outer edge portion 15B is configured to be thicker than the electrolyte base portion 15A as a whole in the lateral direction.

Next, the materials of the elements (negative electrode layer n, positive electrode layer p, and solid electrolyte layer 15) constituting the all-solid-state battery 10 according to the present embodiment and the outline of the manufacturing method of the all-solid-state battery 10 will be described.

[Negative electrode]
As described above, the negative electrode layer n of the present embodiment includes the negative electrode current collector 12 and the negative electrode lithium metal layer 14.

The material constituting the negative electrode current collector 12 is not particularly limited as long as it functions as a current collector applicable to the all-solid-state battery 10 in the technical field according to the present invention. For example, a metal or a resin having conductivity can be adopted.

Specifically, examples of the metal material applicable to the negative electrode current collector 12 include aluminum, nickel, iron, stainless steel, titanium, and copper. In addition to these, a clad material of nickel and aluminum, a clad material of copper and aluminum, and the like may be used. Further, the foil may be a metal surface coated with aluminum. In particular, from the viewpoints of electron conductivity, battery operating potential, adhesion of the negative electrode active material by sputtering to the current collector, and the like, it is preferable to use aluminum, stainless steel, copper, or nickel.

Examples of the conductive resin material applicable to the negative electrode current collector 12 include a resin obtained by adding a conductive filler to a non-conductive polymer material as needed.

In particular, examples of the non-conductive polymer material include polyethylene (PE; high density polyethylene (HDPE), low density polyethylene (LDPE), etc.), polypropylene (PP), polyethylene terephthalate (PET), and polyether nitrile (PEN). ), Polyethylene (PI), Polyamideimide (PAI), Polyethylene (PA), Polytetrafluoroethylene (PTFE), Styrene-butadiene rubber (SBR), Polyacrylonitrile (PAN), Polymethylacrylate (PMA), Polymethylmethacrylate (PMMA), polyvinylidene chloride (PVC), polyvinylidene fluoride (PVdF), polystyrene (PS) and the like can be mentioned.

The negative electrode lithium metal layer 14 is formed between the solid electrolyte layer 15 and the negative electrode current collector 12, and is a layer containing simple substance lithium metal as a main component. The negative electrode lithium metal layer 14 may be configured in advance at the time of manufacturing the all-solid-state battery 10, or may not be provided at the time of manufacturing and may be provided with a predetermined lithium source (solid electrolyte layer 15, positive electrode active material layer 17, etc.) after initial charging. ) May be formed by precipitating lithium supplied from.

[Positive electrode]
The positive electrode layer p is composed of a positive electrode active material layer 17 and a positive electrode current collector 18.

The positive electrode active material layer 17 is configured as an active material capable of reversibly occluding and releasing lithium ions. For example, the material applicable to the positive electrode active material layer 17 is, for example, a lithium metal composite oxide. More specifically, examples of the lithium metal composite oxide include layered rock salt compounds such as LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , LiVO ₂ , or Li (Ni—Mn—Co) O2, LiMn ₂ O ₄ , or LiNi _0.5 . Examples thereof include spinnel-type compounds such as Mn _1.5 O ₄ , olivine-type compounds such as LiFePO ₄ or LiMnPO ₄ , and Si-containing compounds such as Li ₂ FeSiO ₄ or Li ₂ MnSiO ₄ . Examples of the lithium metal composite oxide other than the above include Li ₄ Ti ₅ O ₁₂ .

The positive electrode current collector 18 can be made of the same material as the negative electrode current collector 12.

[Solid electrolyte]
The solid electrolyte layer 15 is a layer containing a solid electrolyte as a main component. Examples of the solid electrolyte include a sulfide solid electrolyte and an oxide solid electrolyte, and a sulfide solid electrolyte is preferable.

In particular, examples of the sulfide solid electrolyte include LiI-Li ₂ S-SiS ₂ , LiI-Li ₂ S-P2O ₅ , LiI-Li ₃ PO ₄ -P ₂ S ₅ , Li ₂ SP 2 S 5, and Li 2 SP ₂ S ₅ . LiI-Li ₃ PS ₄ , LiI-LiBr-Li ₃ PS ₄ , Li ₃ PS ₄ , Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -Li I, Li ₂ SP ₂ S _5- Li ₂ O, Li ₂ S-P ₂ S ₅ -Li ₂ OLiI, Li ₂ S-SiS ₂ , Li ₂ S-SiS ₂ -LiI, Li ₂ S-SiS ₂ -LiBr, Li ₂ S-SiS ₂ -LiC _l , Li ₂ S-SiS ₂ -B ₂ S ₃ -LiI, Li ₂ S-SiS ₂ -P ₂ S ₅ -LiI, Li ₂ SB ₂ S ₃ , Li ₂ SP ₂ S ₅ -Z _m S _n (where _m and _n are positive numbers and Z is one of Ge, Zn or Ga), Li 2S-GeS ₂ , Li 2S _{-SiS 2 - Li 3} PO ₄ or Examples thereof include Li 2S _{-SiS 2 -} Li _x MO _y (where _x and _y are positive numbers and M is any of P, Si, Ge, B, Al, Ga and In). .. The description of "Li ₂ SP _{2 S 5" means a sulfide solid electrolyte using a raw material composition containing Li 2 S and P 2 S 5 , and} the same applies to other descriptions.

Further, the sulfide solid electrolyte may be sulfide glass, crystallized sulfide glass, or a crystalline material obtained by the solid phase method. The sulfide glass can be obtained, for example, by performing mechanical milling (ball mill or the like) on the raw material composition.

[Manufacturing of all-solid-state batteries]
The all-solid-state battery 10 according to the present embodiment can be manufactured by laminating and pressurizing the positive electrode layer p, the solid electrolyte layer 15, and the negative electrode layer n by a known method.

[Action effect]
The configuration of the all-solid-state battery 10 of the present embodiment described above and its action and effect will be collectively described.

The all-solid-state battery 10 of the present embodiment has a solid electrolyte layer 15, a negative electrode layer n including a negative electrode lithium metal layer 14 laminated on one surface of the solid electrolyte layer 15 and depositing metallic lithium, and the other of the solid electrolyte layer 15. Includes a positive electrode layer p laminated on the surface of the surface. The all-solid-state battery 10 is provided on the outer periphery of the electrolyte base portion 15A and the electrolyte base portion 15A that form a surface region sandwiched between the negative electrode layer n and the positive electrode layer p, and extends outward from the negative electrode lithium metal layer 14. It has an electrolyte outer edge portion 15B as an existing outer edge portion. The outer edge portion 15B of the electrolyte is configured such that the surface facing the negative electrode layer n is flush with or concave with respect to the base portion 15A of the electrolyte and protrudes toward the positive electrode layer p.

As a result, even in a scene in which the negative electrode lithium metal layer 14 is stretched outward (for example, when the state of FIG. 1 (b) is changed to the state of FIG. 1 (a)), the electrolyte is placed on the stretched track of the negative electrode outer edge portion 14A. It is possible to realize a configuration in which the outer edge portion 15B does not exist. Therefore, stress transmission due to contact between the negative electrode lithium metal layer 14 and the solid electrolyte layer 15 can be more reliably prevented. On top of that, the shape of the electrolyte outer edge portion 15B protruding toward the positive electrode layer p side ensures the wall thickness of the outer peripheral portion of the solid electrolyte layer 15, so that the strength thereof is improved. That is, in the all-solid-state battery 10 of the present embodiment, the stress concentration is concentrated by preventing the negative electrode outer edge portion 14A, which is easily displaced outward, from coming into contact with the outer peripheral portion of the solid electrolyte layer 15 by devising the structure of the electrolyte outer edge portion 15B described above. In addition to being able to suppress the generation itself, it is also possible to secure the strength of the peripheral portion of the solid electrolyte layer 15 that resists the stress concentration even if it occurs. As a result, the generation of cracks in the solid electrolyte layer 15 that causes a short circuit can be suitably suppressed.

In particular, in the present embodiment, the electrolyte outer edge portion 15B projects toward the positive electrode layer p side over the entire lateral region extending from the electrolyte base portion 15A to the outside of the negative electrode lithium metal layer 14.

As a result, the strength of the outer peripheral portion of the solid electrolyte layer 15 in which stress concentration is particularly likely to occur due to the precipitation of the lithium metal can be increased more reliably. As a result, the generation of cracks in the solid electrolyte layer 15 can be more preferably suppressed.

(Second Embodiment)
Hereinafter, the all-solid-state battery 10 of the second embodiment will be described. The same elements as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 2 is a diagram illustrating the configuration of the all-solid-state battery 10 according to the present embodiment. As shown in the figure, in the all-solid-state battery 10 of the present embodiment, the shape of the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is different from that of the all-solid-state battery 10 of the first embodiment. Specifically, the surface of the electrolyte outer edge portion 15B facing the negative electrode layer n is formed in a concave shape that gradually separates from the negative electrode lithium metal layer 14 toward the outside from the electrolyte base portion 15A. More specifically, the surface of the outer edge portion 15B of the electrolyte facing the negative electrode layer n is formed in a substantially linear shape that inclines toward the positive electrode layer p side (lower in the figure) toward the outside with the electrolyte base portion 15A as a base point. ..

According to this configuration, in addition to the effects described in the first embodiment, the surface pressure acting on the solid electrolyte layer 15 (particularly, the outer edge portion 15B of the electrolyte) from the negative electrode lithium metal layer 14 can be further reduced. Therefore, the stress generated in the solid electrolyte layer 15 due to the stretching of the negative electrode lithium metal layer 14 is further relaxed. As a result, the effect of suppressing the generation of cracks in the solid electrolyte layer 15 that causes a short circuit can be further enhanced.

(Third Embodiment)
Hereinafter, the all-solid-state battery 10 of the third embodiment will be described. The same elements as those in the second embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 3 is a diagram illustrating the configuration of the all-solid-state battery 10 of the present embodiment. As shown in the figure, the all-solid-state battery 10 of the present embodiment faces the surface of the solid electrolyte layer 15 facing the positive electrode layer p and the negative electrode layer n of the electrolyte outer edge portion 15B, based on the configuration of the second embodiment. The surface is formed in a curved shape continuous with the electrolyte base 15A.

More specifically, the surface of the outer edge portion 15B of the electrolyte facing the negative electrode layer n is a curve in a direction gradually separated from the negative electrode layer n as it goes outward with the electrolyte base portion 15A as a base point (particularly, toward the negative electrode layer n). It is formed in the shape of a convex curve).

On the other hand, the surface of the outer edge portion 15B of the electrolyte facing the positive electrode layer p becomes a curve (particularly, concave toward the positive electrode layer p) in a direction gradually approaching the positive electrode current collector 18 toward the outside with the electrolyte base portion 15A as a base point. It is formed in the shape of a curve).

Further, the positive electrode outer edge portion 17A of the positive electrode active material layer 17 and the negative electrode outer edge portion 14A of the negative electrode lithium metal layer 14 are also formed in a curved shape suitable for the surface of the facing electrolyte outer edge portion 15B, respectively.

As described above, in the all-solid-state battery 10 of the present embodiment, the electrolyte outer edge portion 15B is formed in a curved shape in which the surface facing the positive electrode layer p and the surface facing the negative electrode layer n are continuous with respect to the electrolyte base portion 15A. Will be done. Therefore, it is possible to reduce the bending points on the solid electrolyte layer 15 in which stress concentration is likely to occur, as compared with the case where these surfaces are formed in a substantially linear shape (when shown in FIG. 2). As a result, the generation of cracks in the solid electrolyte layer 15 that causes a short circuit can be more reliably suppressed.

(Fourth Embodiment)
Hereinafter, the all-solid-state battery 10 of the fourth embodiment will be described. The same elements as those in any of the first to fourth embodiments are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 4 is a diagram illustrating the configuration of the all-solid-state battery 10 of the present embodiment. As shown in the figure, the all-solid-state battery 10 of the present embodiment is based on the configuration of the third embodiment shown in FIG. 3, while the negative electrode lithium metal layer 14 is configured to extend to the outside of the positive electrode layer p. Will be done. That is, the negative electrode outer edge portion 14A extends outward from the positive electrode outer edge portion 17A. In other words, the all-solid-state battery 10 of the present embodiment is configured so that the existence range of the positive electrode layer p in the surface direction is within the existence range of the negative electrode lithium metal layer 14 in the surface direction.

According to the configuration of the all-solid-state battery 10 of the present embodiment described above, since the negative electrode lithium metal layer 14 extends to the outside of the positive electrode layer p, at least a part of the negative electrode outer edge portion 14A is covered with the positive electrode layer p ( In particular, it can be a non-opposing region with respect to the positive electrode outer edge portion 17A). As a result, excessive precipitation of lithium metal due to current concentration in the negative electrode outer edge portion 14A can be suppressed, and stress concentration on the solid electrolyte layer 15 that can be caused by the precipitation can be alleviated. As a result, the generation of cracks in the solid electrolyte layer 15 that causes a short circuit can be more reliably suppressed.

In this embodiment, based on the configuration of the all-solid-state battery 10 according to the third embodiment, an example of adopting a configuration in which the negative electrode lithium metal layer 14 extends to the outside of the positive electrode layer p has been described. However, the present invention is not limited to this, and the negative electrode lithium metal is based on the configuration of the all-solid-state battery 10 according to the first embodiment (see FIG. 1) or the configuration of the all-solid-state battery 10 according to the second embodiment (see FIG. 2). The structure may be adopted so that the layer 14 extends to the outside of the positive electrode layer p.

(Fifth Embodiment)
Hereinafter, the all-solid-state battery 10 of the fifth embodiment will be described. The same elements as in any of the first to fourth embodiments are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 5 is a diagram illustrating the configuration of the all-solid-state battery 10 of the present embodiment. In particular, FIG. 5A is a schematic plan view of a main part of the all-solid-state battery 10, FIG. 5B is an enlarged view taken along the line AA of FIG. 5A, and FIG. 5C is an enlarged view. FIG. 5 (b) is an enlarged view taken along the line BB in FIG. 5 (b).

Further, in the present embodiment, in the all-solid-state battery 10, the region in which the ratio of the outward stretching amount to the peripheral length of the negative electrode lithium metal layer 14 is relatively large is referred to as “large stretching region C1”. Further, a region in the electrolyte outer edge portion 15B in which the ratio of the outward stretching amount to the peripheral length of the negative electrode lithium metal layer 14 is relatively small is referred to as a “small stretching region C2”.

The large stretched region C1 can be defined as a region in which the ratio of the stretched amount of the negative electrode lithium metal layer 14 before and after undergoing a predetermined number of charge / discharge processes exceeds a predetermined threshold value previously determined by an experiment or the like. On the other hand, the small stretch region C2 can be defined as a region where the measured value of the ratio of the stretch amount is equal to or less than the predetermined threshold value.

In particular, the large stretched region C1 of the present embodiment is a region near the apex of the substantially rectangular negative electrode lithium metal layer 14 (indicated by a broken line square) as shown in FIG. 5 (a). On the other hand, the small extension region C2 is a region (indicated by a square of the alternate long and short dash line) of a portion (side portion in a substantially rectangular shape) other than the vicinity of the apex.

Then, in the small stretch region C2, the outer peripheral portion of the cell unit 10A has the structure shown in FIG. 5 (b). Specifically, in the small stretch region C2, the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A in the electrolyte outer edge portion 15B is formed in substantially the same shape as the electrolyte base portion 15A. That is, in the small stretch region C2, the electrolyte outer edge portion 15B has a structure that does not protrude toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A.

On the other hand, in the large stretch region C1, the outer peripheral portion of the cell unit 10A has the structure shown in FIG. 5 (c). Specifically, in the large stretched region C1, the negative electrode outer edge portion 14A, the electrolyte outer edge portion 15B, and the positive electrode outer edge portion 17A have the same structure as that described in FIG. In particular, in the large stretched region C1, the electrolyte outer edge portion 15B has a structure that protrudes toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A.

Therefore, in the all-solid-state battery 10 of the present embodiment, the amount of protrusion of the electrolyte outer edge portion 15B toward the positive electrode layer p is a region in which the ratio of the amount of outward extension to the peripheral length of the negative electrode lithium metal layer 14 is relatively large. In (large stretch region C1), it is configured to be larger than a region (small stretch region C2) that is relatively small. Therefore, the thickness D of the electrolyte outer edge portion 15B between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A is larger than that of the small stretch region C2 (FIG. 5 (b)) in the large stretch region C1 (FIG. 5 (c)). It will be largely composed.

As a result, in the electrolyte outer edge portion 15B, the portion where particularly strong stress concentration is expected to occur (large stretch region C1) is thickened to locally increase the strength, while the portion where it is not (small stretch region C2) is formed. By making the thickness thinner, the thickness of the positive electrode active material layer 17 can be secured. Therefore, the positive electrode capacity can be maintained relatively high while exerting the effect of suppressing the generation of cracks in the solid electrolyte layer 15.

In this embodiment, as shown in FIG. 5B, the electrolyte outer edge portion 15B does not protrude toward the positive electrode layer p side in the portion between the negative electrode outer edge portion 14A and the positive electrode outer edge portion 17A in the small stretch region C2. Explained. However, the present invention is not limited to this, and a configuration may be adopted in which the electrolyte outer edge portion 15B protrudes toward the positive electrode layer p side even in the small stretch region C2, but the protrusion amount is smaller than the protrusion amount in the large stretch region C1.

Although the embodiments of the present invention have been described above, the above-described embodiments show only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above-described embodiments. not. In addition, the above embodiments can be combined as appropriate.

For example, the all-solid-state battery 10 of the present embodiment can be configured as a laminated battery in which a plurality of stacked cell units 10A are sealed with an exterior material, depending on the intended use. Further, the appearance of the all-solid-state battery 10 of the present embodiment and the electrical connection state (electrode structure) inside are not particularly limited. The appearance of the all-solid-state battery 10 may be, for example, a rectangular flat square shape, a circular shape, or an elliptical shape. Alternatively, the all-solid-state battery 10 may be configured in a cylindrical shape in which one or more cell units 10A are wound and accommodated. Further, as the electrode structure of the all-solid-state battery 10, either a so-called non-bipolar type (internal parallel connection type) or a bipolar type (internal series connection type) may be adopted.

10 All-solid-state battery 14 Negative electrode lithium metal layer 14A Negative electrode outer edge 15 Solid electrolyte layer 15A Electrolyte base 15B Electrolyte outer edge 17 Positive electrode active material layer 17A Positive electrode outer edge n Negative electrode layer p Positive electrode layer

Claims (6)

All including a solid electrolyte layer, a negative electrode layer including a negative electrode lithium metal layer laminated on one surface of the solid electrolyte layer and depositing metallic lithium, and a positive electrode layer laminated on the other surface of the solid electrolyte layer. It ’s a solid-state battery,
The solid electrolyte layer has an electrolyte base portion constituting a surface region sandwiched between the negative electrode layer and the positive electrode layer, and an outer edge portion provided on the outer periphery of the electrolyte base portion and extending outward from the negative electrode lithium metal layer. And have
The outer edge of the solid electrolyte layer is
The surface facing the negative electrode layer is flush with or concave with respect to the electrolyte base portion, and is configured to project toward the positive electrode layer.
All-solid-state battery. The all-solid-state battery according to claim 1.
The outer edge of the solid electrolyte layer is
With the electrolyte base as a base point, it projects toward the positive electrode layer over the entire lateral region extending to the outside of the negative electrode lithium metal layer.
All-solid-state battery. The all-solid-state battery according to claim 1 or 2.
The outer edge of the solid electrolyte layer is
The surface facing the negative electrode layer is formed in a concave shape that separates from the negative electrode lithium metal layer toward the outside from the electrolyte base.
All-solid-state battery. The all-solid-state battery according to claim 3.
The outer edge of the solid electrolyte layer is
The surface facing the positive electrode layer and the surface facing the negative electrode layer are formed in a curved shape continuous with respect to the electrolyte base.
All-solid-state battery. The all-solid-state battery according to any one of claims 1 to 4.
The negative electrode lithium metal layer extends to the outside of the positive electrode layer.
All-solid-state battery. The all-solid-state battery according to any one of claims 1 to 5.
The amount of protrusion toward the positive electrode layer at the outer edge of the solid electrolyte layer is
In the region where the ratio of the outward stretching amount to the peripheral length of the negative electrode lithium metal layer is relatively large, it is larger than in the region where it is relatively small.
All-solid-state battery.

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