JP7747463B2 - Exterior material for all-solid-state battery and all-solid-state battery - Google Patents

Description

This invention relates to an exterior packaging material for all-solid-state batteries used as high-power batteries such as automotive batteries, batteries for portable devices such as mobile electronic devices, and batteries for storing regenerative energy, as well as to all-solid-state batteries.

The commonly used lithium-ion secondary batteries use a liquid electrolyte, which can lead to separator damage due to leakage or the formation of dendrites, and in some cases, can cause a short circuit and lead to fire.

In contrast, all-solid-state batteries use a solid electrolyte, so they do not leak or develop dendrites, and the separator is not damaged. Therefore, there are no concerns about fires caused by separator damage, and they are attracting a great deal of attention from a safety perspective.

A typical all-solid-state battery is constructed by sealing the solid-state battery body, including electrode active materials and solid electrolytes, inside an exterior casing. As research into solid electrolytes progresses, it has gradually become clear that the performance required of the exterior material for these all-solid-state batteries differs from that required for exterior materials for batteries using conventional liquid electrolytes, and various exterior materials have been proposed to meet the performance requirements for all-solid-state batteries.

The basic structure of the exterior material for all-solid-state batteries includes a metal foil layer and a heat-sealing layer (sealant layer) laminated on the inside of it, and the solid-state battery body is encapsulated by heat-sealing the sealant layer.

For example, the all-solid-state battery casing material disclosed in Patent Document 1 below has a protective film interposed between a metal foil layer and a sealant layer, and uses a sealant layer with high hydrogen sulfide gas permeability. Furthermore, the all-solid-state battery casing material disclosed in Patent Document 2 uses a sealant layer with high hydrogen sulfide gas permeability. Furthermore, the all-solid-state battery casing material disclosed in Patent Document 3 uses a gas-absorbing sealant layer. Furthermore, the all-solid-state battery casing material disclosed in Patent Document 4 is configured by laminating a vapor-deposited film layer on the inner surface of the sealant layer.

Patent No. 6777276 Patent No. 6747636 JP 2020-187855 A JP 2020-187835 A

However, while all-solid-state batteries, like conventional batteries, are likely to be used in high-temperature environments, the all-solid-state batteries using the exterior materials shown in Patent Documents 1 to 4 above do not fully consider insulation properties in high-temperature environments, raising concerns about a decline in insulation properties in high-temperature environments.

This invention was made in consideration of the above-mentioned problems, and aims to provide an exterior material for an all-solid-state battery and an all-solid-state battery that can ensure sufficient insulation even in high-temperature environments.

To solve the above problems, the present invention provides the following means.

[1] An exterior material for an all-solid-state battery for encapsulating a solid-state battery body, comprising: a base layer; a metal foil layer laminated on the inner surface side of the base layer; and a sealant layer laminated on the inner surface side of the metal foil layer,
a heat-resistant gas barrier layer is provided between the metal foil layer and the sealant layer;
the heat-resistant gas barrier layer is made of an insulating resin having a melting point 20°C or more higher than that of the sealant layer,
The heat-resistant gas barrier layer has a breakdown voltage of 18 kV/mm or more and a thickness of 3 μm to 50 μm.

[2] The all-solid-state battery packaging material according to paragraph 1, wherein the resin constituting the heat-resistant gas barrier layer has a hot water shrinkage rate of 2% to 10%.

[3] The all-solid-state battery exterior packaging material according to paragraphs 1 or 2, wherein the resin constituting the heat-resistant gas barrier layer is polyamide.

[4] A vapor deposition layer is formed between the gas barrier layer and the sealant layer,
4. The all-solid-state battery exterior material according to any one of items 1 to 3, wherein the vapor deposition layer is composed of at least one of a metal, a metal oxide, and a metal fluoride.

[5] An all-solid-state battery, characterized in that a solid-state battery body is encapsulated in the all-solid-state battery casing material described in any one of items 1 to 4 above.

The all-solid-state battery packaging material of invention [1] has an insulating heat-resistant gas barrier layer interposed between the metal foil layer and the sealant layer, ensuring sufficient insulation even in high-temperature environments.

In the all-solid-state battery packaging material of invention [2], the hot water shrinkage rate of the heat-resistant gas barrier layer is specified, thereby improving formability while maintaining high insulation properties.

The all-solid-state battery casing material of invention [3] uses a general-purpose polyamide resin as the heat-resistant gas barrier layer, making it easy and efficient to manufacture.

The all-solid-state battery packaging material of invention [4] has a vapor-deposited film formed between the heat-resistant gas barrier layer and the sealant layer, further improving gas barrier properties and insulation properties.

Invention [5] specifies an all-solid-state battery that uses the exterior materials of inventions [1] to [4] above, and therefore can achieve the same effects as above.

FIG. 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing an exterior material used in the all-solid-state battery according to the embodiment. FIG. 3 is a plan view showing a schematic diagram of the insulating property evaluation sample. FIG. 4 is a cross-sectional view showing a schematic diagram of the insulating property evaluation sample of FIG. 3, and corresponds to the cross-section taken along line IV-IV of FIG.

Figure 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment of the present invention, and Figure 2 is a schematic cross-sectional view showing an exterior material 1 used in the all-solid-state battery. As shown in both figures, the exterior material 1, which constitutes the casing of the all-solid-state battery according to this embodiment, is composed of a laminated body such as a laminate sheet.

This exterior packaging material 1 comprises a base material layer 11 disposed on the outermost side, a metal foil layer 12 laminated on the inner side of the base material layer 11, a heat-resistant gas barrier layer 21 laminated on the inner side of the metal foil layer 12, and a sealant layer 13 laminated on the inner side of the heat-resistant gas barrier layer 21. In this embodiment, the layers 11-13, 21 of the exterior packaging material 1 are bonded together via adhesives (adhesive layers) using the dry lamination method. In other words, the exterior packaging material 1 of this embodiment is composed of a laminate consisting of base material layer 11/adhesive layer/metal foil layer 12/adhesive layer/heat-resistant gas barrier layer 21/adhesive layer/sealant layer 13.

In this embodiment, as shown in FIG. 1, an all-solid-state battery is produced by enclosing the solid-state battery body 5 in an exterior material 1 having the above-described configuration. That is, two rectangular exterior materials 1, 1 are stacked one on top of the other with the solid-state battery body 5 interposed between them, and the sealant layers 13, 13 on the outer peripheries of the two (pair of) exterior materials 1, 1 are thermally bonded (heat sealed) to form an airtight (sealed) integrated unit, thereby producing an all-solid-state battery in which the solid-state battery body 5 is housed within a bag-shaped casing made of the exterior materials 1, 1.

Although not shown, the all-solid-state battery of this embodiment is provided with a tab lead for electrical extraction. One end (inner end) of this tab lead is adhesively fixed to the solid-state battery body 5, its middle portion passes between the outer peripheral edges of the two exterior bodies 1, 1, and the other end (outer end) is arranged so that it is pulled out to the outside.

In this embodiment, the casing is formed by bonding two planar exterior materials 1, 1 together, but this is not limited to this. In the present invention, at least one of the two exterior materials may be formed into a tray shape in advance, and the tray-shaped exterior material may be bonded to the other tray-shaped or planar exterior material to form the casing.

The detailed configuration of the exterior material 1 of the all-solid-state battery of this embodiment is described below.

The base material layer 11 of the exterior packaging material 1 is composed of a heat-resistant resin film with a thickness of 5 μm to 50 μm. Suitable resins for the base material layer 11 include oriented polyamide, oriented polyester (PET, PBT, PEN), and oriented polyolefin (PE, PP).

The metal foil layer 12 has a thickness of 5 μm to 120 μm and functions to block the penetration of oxygen and moisture from the surface (outer surface). Aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, etc. can be suitably used as the metal foil layer 12. In this embodiment, the terms "aluminum," "copper," and "nickel" are used to include alloys of these materials.

In addition, plating the metal foil layer 12 reduces the risk of pinholes occurring and further improves its ability to block the intrusion of oxygen and moisture.

Furthermore, if the metal foil layer 12 is subjected to a chemical conversion treatment such as chromate treatment, corrosion resistance is further improved, making it possible to more reliably prevent defects such as chipping, and also improves adhesion to the resin, further improving durability.

The sealant layer 13 has a thickness of 10 μm to 100 μm and is made of a film of thermally adhesive (heat-fusible) resin. Suitable resins for the sealant layer 13 include polyethylene (LLDPE, LDPE, HDPE), polyolefins such as polypropylene, olefin copolymers, acid-modified versions of these, and ionomers, such as unstretched polypropylene (CPP, IPP).

Considering that electricity will be extracted using a tab lead, that is, in consideration of sealing and adhesive properties with the tab lead, it is preferable to use a polypropylene resin (non-oriented polypropylene film (CPP, IPP)) for the sealant layer 13.

The heat-resistant gas barrier layer 21 is composed of a resin film that has heat resistance and insulating properties. The resin that constitutes this heat-resistant gas barrier layer 21 is preferably polyamide (PA6, PA66, MXD, etc.), polyester (PET, PBT, PEN, etc.), cellophane, polyvinylidene chloride, etc.

The heat-resistant gas barrier layer 21 of this embodiment has good insulating properties, and maintains good insulating properties even after the solid-state battery body 5 is encapsulated (sealed) by thermal bonding with the exterior material 1 of this embodiment.

In this embodiment, the resin film constituting the heat-resistant gas barrier layer 21 preferably has a volume resistivity of 1×10 ¹⁰ (Ω·m) or more at room temperature (25° C.), and particularly preferably has a volume resistivity of 1×10 ⁵ (Ω·m) or more at 100° C. For reference, the volume resistivity of polyamide such as nylon is 1×10 ¹¹ (Ω·m) at room temperature and about 1×10 ⁷ (Ω·m) at 100° C.

In this embodiment, the resin constituting the heat-resistant gas barrier layer 21 preferably has a predetermined hydrogen sulfide (H ₂ S) gas permeability. Specifically, the heat-resistant gas barrier layer 21 is preferably composed of a resin having a hydrogen sulfide gas permeability of 30 {cc·mm/(m ² ·D·MPa)} or less, as measured in accordance with JIS K7126-1. That is, when the hydrogen sulfide gas permeability of the heat-resistant gas barrier layer 21 is set to the above-mentioned predetermined value or less, the heat-resistant gas barrier layer 21 can prevent the hydrogen sulfide gas from leaking to the outside when the solid electrolyte material reacts with moisture in the outside air to generate hydrogen sulfide gas. In other words, if the hydrogen sulfide gas permeability of the heat-resistant gas barrier layer 21 is too high, there is a risk that the generated hydrogen sulfide gas will leak to the outside through the exterior material 1 (heat-resistant gas barrier layer 21), which is undesirable.

For reference, the "D" included in the unit of hydrogen sulfide gas permeability corresponds to "Day (24h)."

In addition, in this embodiment, the resin that constitutes the heat-resistant gas barrier layer 21 must have a melting point that is at least 20°C higher than the resin that constitutes the sealant layer 13. In other words, if the heat-resistant gas barrier layer 21 has a high melting point, even if the sealant layer 13 melts when the exterior material 1 is thermally bonded, the heat-resistant gas barrier layer 21 can be prevented from melting and flowing out, ensuring that the heat-resistant gas barrier layer 21 can provide gas permeation suppression and insulation properties.

Furthermore, in this embodiment, the heat-resistant gas barrier layer 21 must have a breakdown voltage of 18 kV/mm or more. In other words, if the breakdown voltage of the heat-resistant gas barrier layer 21 is a specific value or higher, sufficient insulation can be reliably ensured. In other words, if the breakdown voltage of the heat-resistant gas barrier layer 21 is too low, sufficient insulation may not be ensured.

In addition, in this embodiment, the thickness of the heat-resistant gas barrier layer 21 must be set to 3 μm to 50 μm. In other words, by setting the thickness of the heat-resistant gas barrier layer 21 within this range, the hydrogen sulfide gas permeation suppression effect described above can be reliably achieved, and even if the sealant layer 13 melts and flows out due to thermal bonding, the heat-resistant gas barrier layer 21 can reliably ensure insulation. In other words, if the heat-resistant gas barrier layer 21 is too thin, there is a risk that the gas permeation suppression effect and insulation properties may not be ensured, which is undesirable. Conversely, if the heat-resistant gas barrier layer 21 is too thick, not only will it be impossible to thin the exterior packaging material 1, but the full effect of making it thicker than necessary will also be undesirable.

In addition, in this embodiment, it is preferable to set the hot water shrinkage rate of the heat-resistant gas barrier layer 21 to 2% to 10%. In other words, when this configuration is adopted, the formability of the heat-resistant gas barrier layer 21, and therefore the exterior packaging material 1, is improved, and high insulation properties can be maintained even after the solid-state battery body 5 is encapsulated in the exterior packaging material 1 by thermal bonding. In other words, if the hot water shrinkage rate of the heat-resistant gas barrier layer 21 falls outside the above specific range, there is a risk that good insulation properties may not be ensured, which is undesirable.

In this embodiment, the hot water shrinkage of the heat-resistant gas barrier layer 21 is the rate of dimensional change in the stretch direction of a resin film test piece (10 cm x 10 cm) that constitutes the heat-resistant gas barrier layer 21 before and after immersion in hot water at 95°C for 30 minutes. In this embodiment, the hot water shrinkage can be calculated using the following formula, where "X" is the dimension in the stretch direction before immersion and "Y" is the dimension in the stretch direction after immersion.

Hot water shrinkage (%) = {(X - Y) / X} x 100
On the other hand, in this embodiment, the adhesive (adhesive layer) for bonding between the layers 11 to 13, 21 of the exterior material 1 can be a curing type such as a two-component curing type or a UV (energy ray) curing type, and among these, a urethane-based adhesive, an olefin-based adhesive, an acrylic-based adhesive, an epoxy-based adhesive, etc. can be preferably used.

In addition, in this embodiment, it is preferable to form a vapor-deposited film (vapor-deposited layer) between the heat-resistant gas barrier layer 21 and the sealant layer 13. That is, an adhesive is provided between the heat-resistant gas barrier layer 21 and the sealant layer 13, and it is preferable to form a vapor-deposited film on at least one of the surface (inner surface) of the heat-resistant gas barrier layer 21 facing the adhesive layer (sealant layer 13) and the surface (outer surface) of the sealant layer 13 facing the adhesive layer (heat-resistant gas barrier layer 21).

In this embodiment, by forming a vapor deposition film, the gas barrier properties can be further improved, and leakage of hydrogen sulfide gas can be more reliably prevented. Furthermore, by preventing gas leakage, the exterior material 1 (casing) of the all-solid-state battery expands, thinning the heat-resistant gas barrier layer 21 and making insulation breakdown less likely to occur, further improving insulation properties.

The vapor-deposited film is preferably composed of at least one of the following materials: metals such as aluminum, titanium, and silicone; metal oxides such as alumina, silica, and zinc oxide; and metal fluorides such as aluminum fluoride and magnesium fluoride.

Furthermore, it is preferable to set the thickness of the vapor deposition layer to 50 Å to 10,000 Å (5 nm to 1,000 nm (0.005 μm to 1 μm)). In other words, by setting the thickness within this range, good gas permeation suppression and insulation properties can be more reliably ensured.

As described above, in the all-solid-state battery of this embodiment, the unique heat-resistant gas barrier layer 21 is interposed between the metal foil layer 12 and the sealant layer 13 in the exterior packaging material 1, ensuring good insulation even in high-temperature environments.

Example 1
1. Fabrication of Exterior Material A chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), a chromium (III) salt compound, water, and alcohol was applied to both sides of a 40 μm thick aluminum foil (A8021-O) serving as the metal foil layer 12, and then dried at 180°C to form a chemical conversion coating. The chromium deposition amount of this chemical conversion coating was 10 mg/ ^m2 per side.

Next, a 15 μm-thick biaxially oriented 6-nylon (O-Ny) film was dry-laminated (attached) to one side (outer surface) of the chemically treated aluminum foil (metal foil layer 12) via a two-component curing urethane adhesive (3 μm) as the substrate layer 11.

Next, as shown in Table 1, a 9 μm thick stretched PA6 (6-nylon) film (O-Ny film) with a melting point of 225°C, a breakdown voltage of 19 kV/mm, and a hot water shrinkage rate of 5% was prepared as the heat-resistant gas barrier layer 21, and a 20 nm thick vapor-deposited aluminum film was formed on one side of the film. The non-vapor-deposited side of this vapor-deposited O-Ny film was then bonded to the other side (inner surface) of the dry-laminated aluminum foil using a two-component curing urethane adhesive (3 μm).

Next, as shown in Table 1, a 20 μm thick CPP film with a melting point of 150°C containing a lubricant (such as erucic acid amide) was laminated as the sealant layer 13 onto the vapor-deposited surface (inner surface) of the dry-laminated O-Ny film (heat-resistant gas barrier layer 21) via a two-component curing urethane adhesive (3 μm). The film was then dry-laminated by being sandwiched between a rubber nip roll and a laminating roll heated to 100°C and pressure-bonded, yielding a laminate that constitutes the exterior packaging material 1.

The laminate was then wound onto a roll shaft and aged at 40°C for 10 days to obtain an exterior material sample for Example 1.

2. Measurement of Breakdown Voltage The breakdown voltage of the resin film constituting the heat-resistant gas barrier layer 21 in Example 1 was measured in accordance with JIS C2151 before the formation of a vapor-deposited film. The results are also shown in Table 1.

3. Measurement of Hot Water Shrinkage Rate A test piece measuring 10 cm × 10 cm was cut out from the resin film constituting the heat-resistant gas barrier layer 21 in Example 1, and the test piece was immersed in hot water at 95°C for 30 minutes. The dimensional change rate in the stretching direction of the test piece before and after immersion was calculated using the following formula.

Hot water shrinkage (%) = {(X - Y) / X} x 100
In this formula, "X" is the dimension in the stretching direction before the immersion treatment, and "Y" is the dimension in the stretching direction after the immersion treatment.

4. Seal strength measurement

Two pieces measuring 15 mm wide x 150 mm long were cut from the packaging material sample of Example 1, and then the pair of samples were overlapped so that their inner sealant layers were in contact with each other. Using a heat sealing device (TP-701-A) manufactured by Tester Sangyo Co., Ltd., heat sealing (thermal bonding) was performed by heating one side under the following conditions: heat sealing temperature: 200°C, sealing pressure: 0.2 MPa (gauge pressure), sealing time: 2 seconds, to obtain a sample for evaluating seal strength of Example 1.

The seal strength evaluation sample was subjected to a T-peel test at a tensile speed of 100 mm/min using a Shimadzu Access Strograph (AGS-5kNX) in accordance with JIS Z0238-1998, with the inner sealant layers of the sealed portion of the seal strength evaluation sample being peeled apart. The peel strength was measured and recorded as the seal strength (N/15 mm width). The results are shown in Table 2.

5. Measurement of Remaining Rate Two pieces measuring 15 mm wide x 150 mm long were cut out of the packaging material sample of Example 1, and then the pair of samples were overlapped so that their inner sealant layers were in contact with each other. Using a heat sealing device (TP-701-A) manufactured by Tester Sangyo Co., Ltd., heat sealing (thermal adhesion) was performed by heating on one side under the following conditions: heat sealing temperature: 200°C, sealing pressure: 0.2 MPa (gauge display pressure), and sealing time: 2 seconds, thereby obtaining a sample for measuring the remaining rate of Example 1.

For this sample for measuring the survival rate, the sealed portion was hardened with resin and cut to expose the cross section. The cross section was then observed using an SEM to determine the thickness of the heat-resistant gas barrier layer 21. The results are also shown in Table 2.

Then, the layer thickness after heat sealing was defined as "da1" and the layer thickness before heat sealing was defined as "da1", and the residual ratio "da1/da0" was measured. The results are also shown in Table 2.

6. Measurement of insulation resistance (evaluation of insulation properties)
As shown in FIGS. 3 and 4 , two pieces of packaging material sample 1 of Example 1 were cut out, each measuring 100 mm long and 50 mm wide. These paired packaging material samples 1, 1 were overlapped with their sealant layers 13 facing each other and in contact with each other. Meanwhile, a 10 mm wide, 100 μm thick aluminum foil tab lead 3 was sandwiched between the pair of packaging material samples 1, 1, with 50 μm thick acid-modified polypropylene tab films 31 placed on both sides of the tab lead 3. At this time, a portion of the tab lead 3 was positioned between the pair of packaging material samples 1, 1, and the remaining portion was pulled outward from the edge of the pair of packaging material samples 1, 1. The sealant layers of these unbonded samples were heat-sealed from both the top and bottom surfaces of the packaging material samples 1, 1 using a double-sided heating heat sealer at a seal width of 5 mm, 200°C, and 0.2 MPa for 2 seconds to obtain a sample for evaluating insulation properties.

In the plan view of the insulation evaluation sample in Figure 3, the thermally bonded portion (heat seal portion) 131 is hatched with diagonal lines to facilitate understanding of the invention. In the cross-sectional view of the insulation evaluation sample in Figure 4, the heat-resistant gas barrier layer 13 is omitted to facilitate understanding of the structure.

Next, as shown in Figure 3, at the longitudinal end of the insulation evaluation sample, the resin serving as the base material layer 11 was partially peeled off to partially expose the aluminum foil serving as the metal foil layer 12, and electrical continuity with the aluminum foil (metal foil layer 12) from the outside was ensured at the exposed portion 121.

One terminal of an insulation resistance measuring device 6 (manufactured by Hioki E.E. Corporation: product number "HIOKI3154") was then connected to the metal foil layer 12 in the exposed portion 121 of the insulation evaluation sample, and the other terminal was brought into contact with the tab lead 3 to form a circuit. A voltage of 25 V was then applied between the metal foil layer 12 and the tab lead 3 in the circuit for 5 seconds, and the resistance was measured to determine the insulation resistance. The results are also shown in Table 2.

7. Evaluation of formability A sample for formability evaluation was obtained by cutting the packaging material sample of Example 1 into a size of 100 mm × 100 mm. A deep-draw forming test was performed on this sample for formability evaluation using a deep-draw forming die attached to a 25-ton press, with the forming height (drawing depth) being changed in 0.5 mm increments.

If the specified formability was achieved even when the molding height was 7 mm or more, it was rated as "◎". If the specified formability was not achieved at 7 mm or more but was achieved in the range of 5 mm or more but less than 7 mm, it was rated as "◯". If the specified formability was not achieved at less than 5 mm, it was rated as "X". The results are also shown in Table 2.

8. Evaluation of H ₂ S gas permeability of O-Ny film with vapor-deposited film The H ₂ S gas permeability was measured according to JIS K7126 for the O-Ny film with vapor-deposited film used in the packaging material sample of Example 1. The results are also shown in Table 2.

Example 2
A sample of Example 2 was prepared in the same manner as in Example 1, except that a 3 μm-thick O—Ny film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 3
A sample of Example 3 was prepared in the same manner as in Example 1, except that a 15 μm-thick O—Ny film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 4
A sample of Example 4 was prepared in the same manner as in Example 1, except that a 25 μm-thick O—Ny film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 5
A sample of Example 5 was prepared in the same manner as in Example 1, except that an O-Ny film having a thickness of 45 μm and a breakdown voltage of 20 kV/mm was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 6
A sample of Example 6 was prepared in the same manner as in Example 1, except that an O-Ny film having a thickness of 12 μm, a breakdown voltage of 18 kV/mm, and a hot water shrinkage rate of 2% was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 7
A sample of Example 7 was prepared in the same manner as in Example 1, except that an O-Ny film having a thickness of 15 μm and a hot water shrinkage rate of 8% was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 8
A sample of Example 8 was prepared in the same manner as in Example 1, except that a PET film having a thickness of 5 μm, a melting point of 260° C., a breakdown voltage of 18 kV/mm, and a hot water shrinkage rate of 0.5% was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 9
A sample of Example 9 was prepared in the same manner as in Example 1, except that an OPP film (biaxially oriented polypropylene film) with a thickness of 5 μm, a melting point of 165° C., a breakdown voltage of 22 kV/mm, and a hot water shrinkage rate of 0.1% was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are also shown in Tables 1 and 2.

Example 10
A sample of Example 10 was prepared in the same manner as in Example 1, except that no vapor-deposited film was formed, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 11
A sample of Example 10 was prepared in the same manner as in Example 1, except that the vapor-deposited film was made of alumina, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 12
A sample of Example 10 was prepared in the same manner as in Example 1, except that a 900 nm thick alumina vapor-deposited film was formed, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

Example 13
A sample of Example 10 was prepared in the same manner as in Example 1, except that a 1200 nm thick alumina vapor-deposited film was formed, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

<Comparative Example 1>
A sample of Comparative Example 1 was prepared in the same manner as in Example 1, except that an O-Ny film with a breakdown voltage of 15 kV/mm was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

<Comparative Example 2>
A sample of Comparative Example 1 was prepared in the same manner as in Example 1, except that a 2 μm-thick O—Ny film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

<Comparative Example 3>
A sample of Comparative Example 1 was prepared in the same manner as in Example 1, except that a 55 μm-thick O—Ny film was used as the heat-resistant gas barrier layer 21, and the same measurements (evaluations) were carried out. The results are shown in Tables 1 and 2.

<Overall review>
As is clear from Table 2, the exterior packaging material samples of Examples 1 to 13 related to the present invention were able to obtain excellent results in all evaluations.

In contrast, the exterior material samples of Comparative Examples 1 to 3, which deviate from the gist of the present invention, failed to achieve favorable results in any of the evaluations.

The all-solid-state battery packaging material of this invention can be suitably used as a casing material for housing the solid-state battery body.

1: Exterior material 11: Base material layer 12: Metal foil layer 13: Sealant layer 21: Heat-resistant gas barrier layer 5: Solid-state battery body

Claims (5)

An exterior material for an all-solid-state battery for encapsulating a solid-state battery body, the exterior material comprising: a base layer; a metal foil layer laminated on an inner surface side of the base layer; and a sealant layer laminated on the inner surface side of the metal foil layer,
a heat-resistant gas barrier layer is provided between the metal foil layer and the sealant layer;
the heat-resistant gas barrier layer is made of an insulating resin having a melting point 20°C or more higher than that of the sealant layer,
the heat-resistant gas barrier layer has a breakdown voltage of 18 kV/mm or more and a thickness of 3 μm to 50 μm ;
the heat-resistant gas barrier layer is made of a resin having a hydrogen sulfide gas permeability of 30 {cc mm/(m2 D MPa)} or less, as measured in accordance with JIS ^K7126-1 . The all-solid-state battery exterior material according to claim 1, wherein the resin constituting the heat-resistant gas barrier layer has a hot water shrinkage rate of 2% to 10%. The exterior material for an all-solid-state battery according to claim 1 or 2, wherein the resin constituting the heat-resistant gas barrier layer is polyamide. a vapor deposition layer is formed between the heat-resistant gas barrier layer and the sealant layer,
The all-solid-state battery exterior material according to any one of claims 1 to 3, wherein the vapor deposition layer is composed of at least one of a metal, a metal oxide, and a metal fluoride. An all-solid-state battery, comprising a solid-state battery body encapsulated in the all-solid-state battery packaging material according to any one of claims 1 to 4.