JP7047630B2 - All solid state battery - Google Patents

Description

The present disclosure relates to an all-solid-state battery. In particular, the present disclosure relates to a battery laminate and an all-solid-state battery having a resin layer covering the battery laminate.

The all-solid-state battery is a battery laminate including one or more unit batteries in which a positive electrode collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order. Have. Further, in the battery laminate, in general, at least one of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector layer is larger than the other layers. It has an extending portion extending outward, and a gap is formed between the extending portions on the side surface of the battery laminate.

When the side surface of the battery laminate having such a gap on the side surface is covered with the resin layer, various techniques have been developed in order to surely embed the resin up to the gap.

For example, in Patent Document 1, a liquid resin is supplied to the side surface of the battery laminate in which a gap is formed between the extending portions, and the resin is cured to cover the side surface with a resin layer. A method for manufacturing an all-solid-state battery is disclosed.

Japanese Unexamined Patent Publication No. 2017-20447

On the other hand, when an all-solid-state battery is used, heat is generated inside the battery, and it is preferable to release this heat to the outside. However, if the side surface of the battery laminate is covered with a resin layer, it may be difficult for the heat generated inside the battery to be released to the outside of the battery.

Therefore, the present disclosure has been made in view of the above circumstances, and is an all-solid-state battery capable of improving the heat dissipation of the battery while reliably covering the gap between the extending portions as described above with the resin layer. The purpose is to provide.

The inventor of the present disclosure has found that the above problems can be solved by the following means.
It has a battery laminate including two or more unit batteries in which a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order.
At least one of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector layer is another layer on the side surface of the battery laminate. It has an extension portion that extends outward from the extension portion, and a gap is formed between the extension portions.
It has a first resin layer filled in the gap, and a second resin layer covering the sides of the first resin layer and the battery laminate.
The first resin layer contains a first inorganic filler having a maximum particle size D1, and the second resin layer contains a second inorganic filler having a maximum particle size D2.
When the height of the gap is H, the maximum particle size D1 and the maximum particle size D2 satisfy the following relational expression:
D1 ≤ 1 / 3H
D2> 1 / 3H
All-solid-state battery.

According to the all-solid-state battery of the present disclosure, since the side surface of the battery laminate is covered with the resin layer, the heat dissipation of the battery through the resin layer is improved while covering the gap between the extending portions. Can be done.

FIG. 1 is a schematic cross-sectional view showing an example of the all-solid-state battery of the present disclosure. FIG. 2 is a schematic cross-sectional view showing an example of a battery laminate for explaining the position of the resin layer. FIG. 3 is a diagram showing the results of thermal conductivity in the all-solid-state batteries of Examples 4 and 5 and Comparative Examples 3 to 5.

Hereinafter, embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. For convenience of explanation, the same reference numerals are given to the same or corresponding parts in each figure, and duplicate explanations will be omitted. Not all of the components of the embodiment are essential, and some components may be omitted. However, the form shown in the figure below is an example of the present disclosure and does not limit the present disclosure.

≪All solid state battery≫
The all-solid-state battery of the present disclosure is
It has a battery laminate including two or more unit batteries in which a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order.
At least one of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector layer extends outward from the other layers on the side surface of the battery laminate. It has a protruding part, and a gap is formed between the extending parts.
It has a first resin layer filled in the gap, and a second resin layer covering the sides of the first resin layer and the battery laminate.
The first resin layer contains a first inorganic filler having a maximum particle size D1 and the second resin layer contains a second inorganic filler having a maximum particle size D2.
When the height of the gap is H, the maximum particle size D1 and the maximum particle size D2 satisfy the following relational expression:
D1 ≤ 1 / 3H
D2> 1 / 3H.

The side surface of the battery laminate is a surface formed by the outer edges of each layer of the unit battery included in the battery laminate.

FIG. 1 is a schematic cross-sectional view showing an example of the all-solid-state battery of the present disclosure. The all-solid-state battery 100 of the present disclosure has a battery laminate 10 including unit batteries 6a, 6b, 6c, and 6d. As shown in FIG. 1, each of the solid electrolyte layer 3b and the solid electrolyte layer 3c has another layer (for example, a positive electrode active material layer 2b and a positive electrode current collector layer 1b (1c)) on the side surface of the battery laminate 10. ), And the extending portions 30b and 30c extending outward from the positive electrode active material layer 2c), and a gap is formed between the extending portions 30b and 30c.

The all-solid-state battery 100 includes a first resin layer 11 filled in the gap between the 30b and 30c, and a second resin layer covering the side surfaces of the first resin layer 11 and the battery laminate 10. Have. At this time, the first resin layer 11 contains the first inorganic filler having the maximum particle size D1, and the second resin layer 12 contains the second inorganic filler having the maximum particle size D2. When the height of the gap between the extending portions 30b and 30c is H, the maximum particle size D1 and the maximum particle size D2 satisfy the following relational expression:
D1 ≤ 1 / 3H
D2> 1 / 3H.

As described above, when the side surface of the battery laminate is covered with the resin layer, it may be difficult for the heat generated inside the battery to be released to the outside of the battery.

The present inventor of the present disclosure has considered to solve this problem by improving the thermal conductivity of the resin layer. Specifically, since there is a positive correlation between the particle size of the inorganic filler and the thermal conductivity, the present inventor of the present disclosure can use the resin layer by incorporating the inorganic filler having a large particle size into the resin layer. We considered improving the thermal conductivity.

However, when the side surface of the battery laminate is coated with a resin layer containing an inorganic filler having a large maximum particle size, the resin cannot be filled in the gap of the battery laminate of the all-solid-state battery or is adjacent to the gap. There was a problem that the layer was damaged.

Therefore, according to the diligent research of the present inventor of the present disclosure, two resin layers (first resin layer and second resin layer) containing inorganic fillers having different maximum particle sizes are used in combination, and each resin layer is used. By satisfying the above-mentioned specific relational expression between the maximum particle size of the contained inorganic filler and the height of the gap between the two extending portions, the inorganic filler having a large maximum particle size is used. I was able to solve such a problem. That is, according to this specific configuration of the present disclosure, it was possible to improve the heat dissipation of the battery through the resin layer while reliably covering the gaps on the side surfaces of the battery laminate with the resin layer.

<Resin layer>
(Position of resin layer)
The all-solid-state battery of the present disclosure has a first resin layer and a second resin layer. The first resin layer fills (covers) the gap between the two extending portions on the side surface of the battery laminate, and the second resin layer covers the side surfaces of the first resin layer and the battery laminate. It is covered (covered).

For example, FIG. 2 is a schematic cross-sectional view showing an example of a battery laminate for explaining the position of the resin layer. As shown in FIG. 2, a plurality of gaps: X1, X2, X3, X4, and X5 are formed on the side surface of the battery laminate 20. Therefore, the first resin layer is filled in each of the gaps X1, X2, X3, X4, and X5, and the second resin layer is filled in each of the gaps X1, X2, X3, X4, and X5. It covers the first resin layer to be filled and the side surface of the battery laminate 20, that is, the region indicated by Y.

As long as the effect of the present disclosure is not impaired, the first resin layer may protrude from the gap and partially enter the covering region of the second resin layer. For example, in FIG. 2, a part of the first resin layer filled in any of the gaps X1, X2, X3, X4, and X5 enters the region indicated by Y to form the second resin layer. It may be in a mixed state.

(Resin material)
In the present disclosure, the resin material constituting the first resin layer and the second resin layer is not particularly limited, and may be the same as the insulating resin material used for a general all-solid-state battery. Further, the resin material constituting the first resin layer and the resin material constituting the second resin layer may be the same or different.

The resin material may be a curable resin or a thermoplastic resin. Further, the curable resin may be a thermosetting resin, a photocurable resin (for example, a UV curable resin), or an electron beam curable resin. More specifically, for example, the material of the resin layer may be an epoxy resin, an acrylic resin, a polyimide resin, a polyester resin, a polypropylene resin, a polyamide resin, a polystyrene resin, a polyvinyl chloride resin, or a polycarbonate resin. Not limited to.

(Inorganic filler)
In the present disclosure, the first resin layer contains a first inorganic filler having a maximum particle size D1, and the second resin layer contains a second inorganic filler having a maximum particle size D2. At this time, when the height of the gap in which the first resin layer is filled is H, the maximum particle size D1 and the maximum particle size D2 satisfy the following relational expression:
D1 ≦ 1 / 3H, 1 / 4H, or 1 / 5H;
D2> 1 / 3H or 1 / H.

In the present disclosure, the maximum particle size of the inorganic filler is the maximum diameter of one inorganic filler regardless of the shape of the inorganic filler. Further, the maximum particle size of the inorganic filler can be observed by SEM, TEM or the like.

The maximum particle size D1 of the first inorganic filler and the maximum particle size D2 of the second inorganic filler are not particularly limited as long as the above relational expression is satisfied, and are set according to the height H of the gap on the side surface of the battery laminate. be able to. When there are two or more gaps, the height of each gap is basically the same, but when the height of each gap is different, the height of the lowest gap is H, and the maximum grain that satisfies the above relational expression. An inorganic filler having a diameter may be selected.

The first inorganic filler and the second inorganic filler may be the same material or different materials as long as the maximum particle diameters of the first inorganic filler and the second inorganic filler satisfy the above relational expression.

The material used for the inorganic filler is not particularly limited as long as it can stably exist in the all-solid-state battery. For example, oxides (alumina (Al ₂ O ₃ ), silica (SiO ₂ ), titania (TIO ₂ ), zirconia (ZrO ₂ ), other CeO ₂ , Y ₂ O ₃ , La ₂ O ₃ , LiAlO ₂ , Li ₂ O, BeO, B ₂ O ₃ , Na ₂ O, MgO, P ₂ O ₅ , CaO, Cr ₂ O ₃ , Fe ₂ O ₃ , ZnO, etc.), Porous composite ceramics (zeolite, sepiolite, parigol skit, etc.), nitride Substances (Si ₃ N ₄ , BN, AIN, TiN, Ba ₃ N ₂ , etc.), carbides (SiC, ZrC, B ₄ C), carbonates (MgCO ₃ , CaCO ₃ , etc.), or sulfates (CaSO ₄ , BaSO). ₄ etc.) etc. are used as inorganic fillers, but are not limited thereto. Further, the material used for these inorganic fillers may be a single material or a mixture of two or more kinds.

The shape of the inorganic filler is not particularly limited, and may be spherical, elliptical, fibrous, scaly, or the like.

In the present disclosure, the content of the first inorganic filler contained in the first resin layer is not particularly limited. For example, when the total amount of the resin material constituting the first resin layer is 100 wt%, the content of the first inorganic filler is 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more. , 30 wt% or more, 35 wt% or more, 40 wt% or more, 45 wt% or more, 50 wt% or more, 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, or 75 wt% or more, and 90 wt%. Below, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70 wt% or less, 65 wt% or less, 60 wt% or less, 55 wt% or less, 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, It may be 25 wt% or less, 20 wt% or less, 15 wt% or less, or 10 wt% or less.

Further, the content of the second inorganic filler contained in the second resin layer is not particularly limited. For example, when the total amount of the resin material constituting the second resin layer is 100 wt%, the content of the second inorganic filler is 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more. , 30 wt% or more, 35 wt% or more, 40 wt% or more, 45 wt% or more, 50 wt% or more, 55 wt% or more, 60 wt% or more, 65 wt% or more, 70 wt% or more, or 75 wt% or more, and 90 wt%. Below, 85 wt% or less, 80 wt% or less, 75 wt% or less, 70 wt% or less, 65 wt% or less, 60 wt% or less, 55 wt% or less, 50 wt% or less, 45 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, It may be 25 wt% or less, 20 wt% or less, 15 wt% or less, or 10 wt% or less.

<Battery laminate>
In the present disclosure, the battery laminate includes two or more unit batteries in which a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order. ..

For example, the battery laminate 10 shown in FIG. 1 has four unit batteries 6a, 6b, 6c and 6d. Further, the unit battery 6a is formed by laminating a positive electrode current collector layer 1a, a positive electrode active material layer 2a, a solid electrolyte layer 3a, a negative electrode active material layer 4a, and a negative electrode current collector layer 5a (5b) in this order. The unit battery 6b is formed by laminating a negative electrode current collector layer 5a (5b), a negative electrode active material layer 4b, a solid electrolyte layer 3b, a positive electrode active material layer 2b, and a positive electrode current collector layer 1b (1c) in this order. .. The unit battery 6c is formed by laminating a positive electrode collector layer 1b (1c), a positive electrode active material layer 2c, a solid electrolyte layer 3c, a negative electrode active material layer 4c, and a negative electrode current collector layer 5c (5d) in this order. .. The unit battery 6 is formed by laminating a negative electrode current collector layer 5c (5d), a negative electrode active material layer 4d, a solid electrolyte layer 3d, a positive electrode active material layer 2d, and a positive electrode current collector layer 1d in this order.

In the present disclosure, the battery laminate may be a monopolar type battery laminate or a bipolar type battery laminate.

In the case of a monopolar type battery laminate, the two unit batteries adjacent to each other in the stacking direction may have a monopolar type configuration sharing the positive electrode current collector layer or the negative electrode current collector layer. For example, as shown in FIG. 1, adjacent unit batteries 6a and 6b share a negative electrode current collector layer 5a (5b), and adjacent unit batteries 6b and 6c share a positive electrode current collector layer. 1b (1c) is shared, and adjacent unit batteries 6c and 6d share a negative electrode current collector layer 5c (5d), and these unit batteries 6a, 6b, 6c and 6d are combined into a monopolar. It constitutes a type of battery laminate 10.

In the case of a bipolar type battery laminate, the two unit batteries adjacent to each other in the stacking direction have a bipolar type configuration sharing a positive electrode / negative electrode current collector layer used as both a positive electrode and a negative electrode current collector layer. good. Therefore, for example, the battery laminate may be a laminate of three unit batteries sharing a positive electrode / negative electrode current collector layer used as both a positive electrode and a negative electrode current collector layer, and specifically, a positive electrode current collector. Body layer, positive electrode active material layer, solid electrolyte layer, negative electrode active material layer, positive electrode / negative electrode current collector layer, positive electrode active material layer, solid electrolyte layer, negative electrode active material layer, positive electrode / negative electrode current collector layer, positive electrode active material A layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer can be provided in this order (not shown). Further, in this case, since the "positive electrode / negative electrode current collector layer" is used as both the positive electrode and the negative electrode current collector layer, the "positive electrode current collector layer" or the "negative electrode current collector layer" referred to in the present disclosure. It applies to any of the above.

In the present disclosure, at least one of the positive electrode collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector layer is more than the other layers on the side surface of the battery laminate. If there is an extending portion extending outward and a gap is formed between the extending portions, the layer having the extending portion is a positive electrode current collector layer, a positive electrode active material layer, and a solid electrolyte layer. , The negative electrode active material layer, and the negative electrode current collector layer are not limited to any of the layers.

In a laminated all-solid-state battery represented by a lithium ion battery, a negative electrode active material layer and a negative electrode are used in order to reliably and smoothly move the lithium ions released from the positive electrode active material layer to the negative electrode active material layer during charging. It is preferable that the current collector layer is formed in a larger area than the positive electrode active material layer and the positive electrode current collector layer. Therefore, it is preferable that the negative electrode active material layer, the negative electrode current collector layer, and the solid electrolyte layer have an extending portion.

Further, the all-solid-state battery of the present disclosure has a positive electrode current collector tab electrically connected to the positive electrode current collector layer and a negative electrode current collector tab electrically connected to the negative electrode current collector layer. You may be doing it. In this case, these current collecting tabs may protrude from the resin layer. According to this configuration, the electric power generated in the battery laminate can be taken out to the outside through the current collector tab.

Further, the positive electrode current collector layer may have a positive electrode current collector protruding portion protruding in the plane direction, and a positive electrode current collecting tab may be electrically connected to the positive electrode current collector protruding portion. .. Similarly, the negative electrode current collector layer may have a negative electrode current collector protruding portion, and a negative electrode current collector tab may be electrically connected to the negative electrode current collector protruding portion.

In the all-solid-state battery of the present disclosure, the battery laminate can be constrained in the stacking direction. Thereby, during charging / discharging, the conductivity of ions and electrons can be improved inside each layer of the all-solid-state battery laminate and between each layer, and the battery reaction can be further promoted.

Hereinafter, each member of the battery laminate will be described in detail. In order to easily understand the present disclosure, each member of the battery laminate of the all-solid-state lithium-ion secondary battery will be described as an example, but the all-solid-state battery of the present disclosure is limited to the lithium-ion secondary battery. It can be widely applied.

(Positive current collector layer)
The conductive material used for the positive electrode current collector layer is not particularly limited, and any material that can be used for an all-solid-state battery can be appropriately adopted. For example, the conductive material used for the positive electrode current collector layer may be, but is not limited to, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like.

The shape of the positive electrode current collector layer is not particularly limited, and examples thereof include a foil shape, a plate shape, and a mesh shape. Of these, foil-like is preferable.

(Positive electrode active material layer)
The positive electrode active material layer contains at least a positive electrode active material, and preferably further contains a solid electrolyte described later. In addition, an additive used for the positive electrode active material layer of an all-solid-state battery such as a conductive auxiliary agent or a binder can be included according to the intended use and purpose of use.

The material of the positive electrode active material is not particularly limited. For example, the positive electrode active material is lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , Li _{1 + x.} Different element substitution Li-Mn spinel having a composition represented by Mn _{2- xy My} O ₄ (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn) and the like. However, it is not limited to these.

The conductive auxiliary agent is not particularly limited. For example, the conductive auxiliary agent may be, but is not limited to, a carbon material such as VGCF (vapor grown carbon fiber) and carbon nanofibers, and a metal material.

The binder is not particularly limited. For example, the binder may be, but is not limited to, a material such as polyvinylidene fluoride (PVdF), carboxymethyl cellulose (CMC), butadiene rubber (BR) or styrene butadiene rubber (SBR), or a combination thereof.

(Solid electrolyte layer)
The solid electrolyte layer contains at least a solid electrolyte. The solid electrolyte is not particularly limited, and a material that can be used as a solid electrolyte for an all-solid-state battery can be used. For example, the solid electrolyte may be, but is not limited to, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer electrolyte, or the like.

Examples of the sulfide solid electrolyte include, but are not limited to, a sulfide-based amorphous solid electrolyte, a sulfide-based crystalline solid electrolyte, and an argylodite-type solid electrolyte. As specific examples of sulfide solid electrolytes, Li ₂ SP ₂ S ₅ series (Li ₇ P ₃ S ₁₁ , Li ₃ PS ₄ , Li ₈ P ₂ S ₉ , etc.), Li ₂ S-SiS ₂ , Li I -Li ₂ S-SiS ₂ , LiI-Li ₂ SP ₂ S ₅ , LiI-LiBr-Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -GeS ₂ (Li ₁₃ GeP ₃ S ₁₆ ) , Li ₁₀ GeP ₂ S ₁₂ , etc.), LiI-Li ₂ SP ₂ O ₅ , LiI-Li ₃ PO ₄ -P ₂ S ₅ , Li _7-x PS _6-x Cl _x , etc .; or a combination thereof. It can be mentioned, but is not limited to these.

Examples of solid oxide electrolytes are Li ₇ La ₃ Zr ₂ O _12, Li _7-x La ₃ Zr _1-x Nb _x O _12, Li _7-3 x La ₃ Zr ₂ Al _x O ₁₂ , Li _{3 x} La _{2 / 3-x} TiO ₃ , Li _{1 + x} Al _x Ti _2-x (PO ₄ ) ₃ , Li _{1 + x} Al _x Ge _2-x (PO ₄ ) ₃ , Li ₃ PO ₄ or Li _{3 + x} PO _4-x N _x (LiPON ), Etc., but are not limited to these.

(Polymer electrolyte)
Examples of the polymer electrolyte include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

The solid electrolyte may be glass or crystallized glass (glass ceramic). Further, the solid electrolyte layer may contain a binder or the like, if necessary, in addition to the above-mentioned solid electrolyte. As a specific example, it is the same as the "binder" listed in the above-mentioned "positive electrode active material layer", and the description thereof is omitted here.

(Negative electrode active material layer)
The negative electrode active material layer contains at least the negative electrode active material, and preferably further contains the above-mentioned solid electrolyte. In addition, an additive used for the negative electrode active material layer of an all-solid-state battery such as a conductive auxiliary agent or a binder can be included according to the intended use and purpose of use.

The material of the negative electrode active material is not particularly limited, and it is preferable that metal ions such as lithium ions can be occluded and released. For example, the negative electrode active material may be an alloy-based negative electrode active material, a carbon material, or the like, but is not limited thereto.

The alloy-based negative electrode active material is not particularly limited, and examples thereof include a Si alloy-based negative electrode active material and a Sn alloy-based negative electrode active material. Examples of the Si alloy-based negative electrode active material include silicon, silicon oxide, silicon carbide, silicon nitride, and a solid solution thereof. Further, the Si alloy-based negative electrode active material may contain elements other than silicon, for example, Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti and the like. Sn alloy-based negative electrode active materials include tin, tin oxide, tin nitride, and solid solutions thereof. Further, the Sn alloy-based negative electrode active material can contain elements other than tin, for example, Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si and the like. Among these, a Si alloy-based negative electrode active material is preferable.

The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, and the like.

As the solid electrolyte, the conductive auxiliary agent, the binder and other additives used for the negative electrode active material layer, those described in the above-mentioned "Positive electrode active material layer" and "Solid electrolyte layer" can be appropriately adopted. ..

(Negative electrode current collector layer)
The conductive material used for the negative electrode current collector layer is not particularly limited, and any material that can be used for an all-solid-state battery can be appropriately adopted. For example, the conductive material used for the negative electrode current collector layer may be, but is not limited to, SUS, aluminum, copper, nickel, iron, titanium, carbon, or the like.

The shape of the negative electrode current collector layer is not particularly limited, and examples thereof include a foil shape, a plate shape, and a mesh shape. Of these, foil is preferable.

In the present disclosure, the second resin layer covers the side surface of the all-solid-state battery laminate. As a result, it is not necessary to have an exterior body such as a laminated film or a metal can on the outside of the all-solid-state battery of the present disclosure. Therefore, the all-solid-state battery of the present disclosure is more compact than the conventional all-solid-state battery that requires an exterior body, which also leads to an improvement in the energy density of the battery. However, one of the present disclosures may further have these exterior bodies.

Further, in the all-solid-state battery of the present disclosure, the upper end face and the lower end face in the stacking direction of the battery laminate are covered with a film or the like, and at least the side surface of the all-solid-state battery laminate is the second resin layer. It may be an all-solid-state battery covered with. Further, the all-solid-state battery of the present disclosure may be an all-solid-state battery in which the upper end face and / or the lower end face in the stacking direction of the all-solid-state battery laminate is also covered with a resin layer.

≪Types of all-solid-state batteries≫
In the present disclosure, examples of the all-solid-state battery include an all-solid-state lithium ion battery, an all-solid-state sodium ion battery, an all-solid-state magnesium ion battery, and an all-solid-state calcium ion battery. Of these, an all-solid-state lithium-ion battery and an all-solid-state sodium-ion battery are preferable, and an all-solid-state lithium-ion battery is particularly preferable.

Further, the all-solid-state battery of the present disclosure may be a primary battery or a secondary battery, but among them, a secondary battery is preferable. This is because the secondary battery can be repeatedly charged and discharged, and is useful as, for example, an in-vehicle battery. Therefore, it is preferable that the all-solid-state battery of the present disclosure is an all-solid-state lithium-ion secondary battery.

The present disclosure will be described in more detail with reference to the examples shown below, but the scope of the present disclosure is not limited to the examples.

<Example 1>
A battery laminate having a negative electrode current collector layer, a negative electrode active material layer, and a solid electrolyte layer having an extending portion and a gap having a height H of 135 μm was prepared. By applying the capillary underfill method, the resin material A was filled in the gaps on the side surfaces of the battery laminate and cured to form the first resin layer. At this time, the resin material A is an epoxy resin manufactured by Namics, and contains 30 wt% of silica (SiO ₂ ) as an inorganic filler. The maximum particle size of silica (SiO ₂ ) was 15 μm.

<Examples 2 and 3 and Comparative Examples 1 and 2>
Examples 2 and 3 and Comparative Examples 1 and 2, respectively, in the same manner as in Example 1 except that the maximum particle size of silica contained in the resin material A was changed as shown in Table 1 below. A first resin layer was formed on the surface.

(Interim evaluation)
The results of forming the first resin layer in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated by cross-sectional photographs. The evaluation results are shown in Table 1.

As is clear from the results in Table 1, in Examples 1 to 3, the inorganic filler having a maximum particle size of 1/3 or less of the height of the gap (135 μm), that is, an inorganic filler having a maximum particle size of 45 μm or less. In each of the first resin layers containing the above, the first resin layer could be surely formed in the gap. On the other hand, in Comparative Examples 1 and 2, the battery laminate was damaged and there was a place where the resin layer could not be filled in the gap.

<Examples 4 and 5 and Comparative Examples 3 to 5>
Next, using the sample of Example 1 described above, a second resin layer was formed on the side surfaces of the first resin layer and the battery laminate using the resin material B. At this time, the resin material B is an epoxy resin manufactured by Panasonic Corporation, and contains 70 wt% of silica (SiO ₂ ) as an inorganic filler. The maximum particle size of silica (SiO ₂ ) is as shown in Table 2 below.

(Evaluation of thermal conductivity)
The thermal conductivity was measured with respect to the manufactured Examples 4 and 5 and the all-solid-state batteries of Comparative Examples 3 to 5. The results are shown in Table 2 and FIG.

As is clear from the results in Table 2 and FIG. 3 , the all-solid-state batteries of Examples 4 and 5 are inorganic fillers having a maximum particle size of more than 1/3 of the gap height (135 μm), that is, a maximum particle size. Any second resin layer containing an inorganic filler having a diameter of more than 45 μm could be formed. Further, it was found that the thermal conductivity of the all-solid-state batteries of Examples 4 and 5 was 0.66 W / mk and 0.51 W / mk, respectively, which contributed to the improvement of the heat dissipation of the batteries.

1,1a, 1b, 1c, 1d Positive Electrode Collector Layer 1e, 1f, 1g, 1h, 1j, 1k, 1l Positive Electrode Collector Layer 2, 2a, 2b, 2c, 2d Positive Electrode Active Material Layer 2e, 2f, 2g , 2h, 2j, 2k, 2l Positive electrode active material layer 3, 3a, 3b, 3c, 3d, solid electrolyte layer 3e, 3f, 3g, 3h, 3j, 3k, 3l solid electrolyte layer 4, 4a, 4b, 4c, 4d Negative electrode active material layer 4e, 4f, 4g, 4h, 4j, 4k, 4l Negative electrode active material layer 5, 5a, 5b, 5c, 5d Negative electrode current collector layer 5e, 5f, 5g, 5h, 5j, 5k, 5l Negative electrode collection Electrical layer 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6j, 6k, 6l Unit battery 10, 20 Battery laminate 11 First resin layer 12 Second resin layer 30b Solid electrolyte layer 3b Extension part 30c Extension part of solid electrolyte layer 3c 100 All-solid-state battery

Claims (1)

It has a battery laminate including two or more unit batteries in which a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order.
At least one of the positive electrode current collector layer, the positive electrode active material layer, the solid electrolyte layer, the negative electrode active material layer, and the negative electrode current collector layer is another layer on the side surface of the battery laminate. It has an extension portion that extends outward from the extension portion, and a gap is formed between the extension portions.
It has a first resin layer filled in the gap, and a second resin layer covering the sides of the first resin layer and the battery laminate.
The first resin layer contains a first inorganic filler having a maximum particle size D1, and the second resin layer contains a second inorganic filler having a maximum particle size D2.
When the height of the gap is H, the maximum particle size D1 and the maximum particle size D2 satisfy the following relational expression:
D1 ≤ 1 / 3H
D2> 1 / 3H
The shape of the first inorganic filler and the second inorganic filler is spherical or ellipsoidal.
The content of the first inorganic filler contained in the first resin layer is 10 wt% or more and 80 wt% or less when the total amount of the resin material constituting the first resin layer is 100 wt%.
The content of the second inorganic filler contained in the second resin layer is 10 wt% or more and 80 wt% or less when the total amount of the resin material constituting the second resin layer is 100 wt%.
All-solid-state battery.

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