Battery packaging material and battery

Abstract

The invention relates to the technical field of battery packaging, and discloses a battery packaging material and a battery. The battery packaging material comprises an outer base material layer, a middle metal layer and an inner heat sealing layer which are arranged in sequence, the outer base material layer comprises a first base material layer and a second base material layer; and the ratio of the ductility of the first base material layer to the ductility of the second base material layer in the same direction is (0.85-1.1): 1. The packaging material has good formability, and the safety of the battery can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery packaging, and in particular to battery packaging materials and batteries. Background Art

[0002] Currently, lithium-ion batteries are divided into three main categories: prismatic, cylindrical, and soft-pack. Prismatic and cylindrical battery casings primarily utilize hard shells made of aluminum, iron, and their alloys, while soft-pack battery casings utilize a metal composite film composed of a laminate of metal foil and resin, significantly improving the rigid design of hard-shell batteries.

[0003] The structure of the metal composite film is, from the outside to the inside, an outer base material layer, an outer adhesive layer, an intermediate metal layer and an inner welding resin layer.

[0004] Traditional lithium-ion battery packaging materials have problems such as poor formability, easy breakage, and insufficient resistance to electrolyte corrosion, which limit the further improvement of battery performance.

[0005] During use, power battery packs may be damaged by vibration, foreign matter, and other factors, which can cause damage to the battery packaging. This damage can expose the intermediate metal layer to air, leading to oxidation and even exposure to air in the battery cell's internal materials. This contact with air can cause rapid degradation of the battery cell's internal materials and even lead to thermal runaway. This problem can be even more serious than the loss of life caused by a short circuit-induced thermal runaway accident. Therefore, battery packaging materials must have excellent puncture resistance.

[0006] Furthermore, to further extend the life of lithium-ion batteries, the intermediate metal layer and the inner weld resin layer must maintain long-term, stable bonding strength. Furthermore, because power batteries must maintain good performance at relatively high temperatures, the inner adhesive must have a certain level of bonding strength, and the inner weld layer must have relatively stable welding strength at high temperatures.

[0007] In view of this, the present invention is proposed. Summary of the Invention

[0008] An object of the present invention is to provide a battery packaging material and a battery, aiming to improve at least one of the problems mentioned in the background art.

[0009] The present invention is achieved in that:

[0010] In a first aspect, the present invention provides a battery packaging material comprising an outer substrate layer, an intermediate metal layer, and an inner heat-sealing layer arranged in sequence;

[0011] The outer substrate layer includes a first substrate layer and a second substrate layer closer to the intermediate metal layer than the first substrate layer;

[0012] The ratio of the elongation of the first substrate layer and the second substrate layer in the same direction is (0.85-1.1):1.

[0013] In an optional embodiment, the ratio of the elongation of the first substrate layer to the second substrate layer in the MD direction is (0.85-1.09):1, and the ratio in the TD direction is (0.85-1.1):1.

[0014] In an optional embodiment, the elongation of the first substrate layer in the MD direction is 110% to 140%; the elongation of the second substrate layer in the MD direction is 100% to 130%;

[0015] Preferably, the elongation of the first substrate layer in the MD direction is 104-125%, and the elongation of the second substrate layer in the TD direction is 110-128%.

[0016] In an optional embodiment, the ratio of the elongation of the first substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1); the ratio of the elongation of the second substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1);

[0017] Preferably, the ratio of the elongation of the first substrate layer in the MD direction to the elongation in the TD direction is 1:(0.72-0.98); the ratio of the elongation of the second substrate layer in the MD direction to the elongation in the TD direction is 1:(0.74-0.98).

[0018] In an optional embodiment, the ratio of the thickness of the first substrate layer to the second substrate layer is (0.5-1.1):1;

[0019] Preferably, the ratio of the thickness of the first substrate layer to the thickness of the second substrate layer is (0.667-1):1.

[0020] In an optional embodiment, calculated as elongation at break in %, and thickness in μm, the ratio of the elongation at break of the intermediate metal layer to its thickness is greater than 0.25.

[0021] In an optional embodiment, the inner heat-sealing layer includes a composite heat-sealing adhesive layer and a heat-sealing weld layer.

[0022] In an optional embodiment, the melting temperature of the heat-sealing adhesive layer is 138.6 to 145° C., and the melting temperature of the heat-sealing weld layer is 153 to 160° C.;

[0023] Preferably, the melting temperature of the heat-sealing adhesive layer is 138.6-144.6°C, and the melting temperature of the heat-sealing weld layer is 153.3-158.9°C.

[0024] In an optional embodiment, the side of the intermediate metal layer in contact with the inner heat seal layer is subjected to an anti-corrosion treatment to form an inner passivation layer;

[0025] The side of the intermediate metal layer in contact with the outer base material layer is treated with anti-corrosion to form an outer passivation layer.

[0026] In a second aspect, the present invention provides a battery, which is packaged using the battery packaging material according to any one of the aforementioned embodiments.

[0027] The present invention has the following beneficial effects:

[0028] The battery packaging material provided by the present invention can control the timing of the fracture of the two materials during the molding process by limiting the ratio of the elongation of the two substrate layers in the same direction in the outer substrate layer to within an appropriate range, thereby achieving the effect of improving the molding limit. The higher molding limit means that there is more molding margin compared to ordinary battery packaging, which can maintain better safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic structural diagram of the battery packaging material provided by the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0032] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0033] like Figure 1 As shown, a battery packaging material provided by an embodiment of the present invention includes an outer base material layer, an intermediate metal layer and an inner heat-sealing layer arranged in sequence;

[0034] The outer substrate layer includes a first substrate layer and a second substrate layer, wherein the first substrate layer is farther away from the intermediate metal layer than the second substrate layer;

[0035] The ratio of the elongation of the first substrate layer and the second substrate layer in the same direction is (0.85-1.1):1.

[0036] The battery packaging material provided by the present invention can control the timing of the fracture of the two materials during the molding process by limiting the ratio of the elongation of the two substrate layers in the same direction in the outer substrate layer to within an appropriate range, thereby achieving the effect of improving the molding limit. The higher molding limit means that there is more molding margin compared to ordinary battery packaging, which can maintain better safety.

[0037] Preferably, the ratio of the elongation of the first substrate layer to that of the second substrate layer in the MD direction is (0.85-1.09):1, and the ratio in the TD direction is (0.85-1.1):1.

[0038] Optionally, to further ensure that the outer substrate layer is not easily damaged, the elongation of the first substrate layer in the MD direction is 110% to 140%, preferably 104 to 125%; the elongation of the second substrate layer in the MD direction is 100% to 130%, preferably 110 to 128%.

[0039] Optionally, the ratio of the elongation of the first substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1), preferably 1:(0.72-0.98); the ratio of the elongation of the second substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1), preferably 1:(0.74-0.98);

[0040] Preferably, the first substrate layer has a tensile strength of 180-240 MPa in the MD direction and / or TD direction, taking into account the formability, and preferably 200-220 MPa to meet the elongation requirement.

[0041] The substrate material that satisfies the requirements of the first substrate layer is, for example, one or more mixtures of ethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene isophthalate and copolyester.

[0042] Preferably, the second substrate layer has a tensile strength of 240-350 MPa in the MD direction and / or TD direction, taking into account the formability, and preferably 280-320 MPa to meet the elongation requirement.

[0043] The substrate that satisfies the requirements of the first substrate layer may be, for example, one or more mixtures of aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66.

[0044] In order to adjust the elongation and strength of the first substrate layer and the second substrate layer to reach target values, the substrate may be modified or additives may be added to the substrate.

[0045] Optionally, to ensure that the battery packaging material has better strength, the thickness of the first substrate layer is, for example, 6 to 40 μm, preferably 12 to 40 μm, and the thickness of the second substrate layer is, for example, 15 to 50 μm, preferably 25 to 50 μm.

[0046] Optionally, to ensure the durability and resistance of the packaging material, the first substrate layer may have a tensile strength of at least 180 MPa in both the MD and TD directions, with a ratio of tensile strength in the MD to tensile strength in the TD of (0.6-1):1; and / or the second substrate layer may have a tensile strength of at least 240 MPa in both the MD and TD directions, with a ratio of tensile strength in the MD to tensile strength in the TD of 1:(0.9-1.2). The higher the strength of the first and second substrate layers, the better; higher strengths increase the resistance to damage.

[0047] Optionally, in order to further improve the forming limit, the thickness ratio of the first substrate layer to the second substrate layer is (0.5-1.1):1, preferably (0.667-1):1.

[0048] Optionally, the ratio of the elongation at break of the intermediate metal layer to its thickness, calculated in %, and measured in μm, is ≥ 0.25. With a higher elongation, the foil loses less thickness when stretched for the same distance. Furthermore, a higher elongation can increase the forming limit, which can increase the foil thickness and survivability at the same forming depth compared to a foil with a lower forming limit.

[0049] Optionally, to satisfy the above-mentioned range of the ratio of the elongation at break of the metal layer to its thickness, the thickness of the intermediate metal layer is, for example, 20 to 100 μm, preferably 40 to 80 μm, and more preferably 60 to 80 μm. The material of the intermediate metal layer is, for example, aluminum foil, copper foil, steel foil, and alloys thereof.

[0050] Optionally, the inner heat-sealing layer can be a single-layer structure or a multi-layer structure. Preferably, in order to make the packaging material have better performance, the inner heat-sealing layer is composed of at least two single-layer films through co-extrusion.

[0051] Optionally, the inner heat-sealing layer includes a composite heat-sealing adhesive layer and a heat-sealing weld layer, and the heat-sealing adhesive layer is closer to the middle metal layer than the heat-sealing weld layer.

[0052] Optionally, the melting temperature of the heat-sealing adhesive layer is 138.6-145° C., and the melting temperature of the heat-sealing weld layer is 153-160° C. When the melting temperatures of the heat-sealing adhesive layer and the heat-sealing weld layer are within this range, they have relatively stable bonding strength and weld strength, and good stability at high temperatures.

[0053] Optionally, in order to make the heat-sealing adhesive layer and the heat-sealing welding layer meet the above parameter requirements, the thickness of the heat-sealing adhesive layer is, for example, 20 to 60 μm, and the material is, for example, maleic anhydride modified polypropylene; the thickness of the heat-sealing welding layer is, for example, 20 to 60 μm, and the material is, for example, random polypropylene resin.

[0054] Optionally, the materials of the heat-seal adhesive layer and the heat-seal welding layer are mainly heat-sealable, without any particular limitation, and are preferably resins containing a polyolefin main chain, such as polyolefin and acid-modified polyolefin.

[0055] Specific examples of polyolefins include polyethylene-α-olefin copolymers such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylene such as homopolypropylene, polypropylene block copolymers (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. The polyolefin resin used as a copolymer may be a block copolymer or a random copolymer. These polyolefin-based resins may be used alone or in combination of two or more.

[0056] Acid-modified polyolefins are polymers modified by block polymerization or graft polymerization of an acid component with a polyolefin. Acid-modified polyolefins may include copolymers obtained by copolymerizing a polar molecule such as polyacrylic acid or methacrylic acid with the above-mentioned polyolefin. Furthermore, the acid component used in the acid modification may include carboxylic acids or sulfonic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, and their anhydrides. Acrylic acid or maleic acid and their anhydrides are preferred.

[0057] The heat-seal adhesive layer and the heat-seal welding layer can be composed of a single resin or a combination of two or more resins. The inner heat-welding layer can be composed of only one layer or two or more layers of the same or different resins.

[0058] Optionally, the heat-sealing adhesive layer uses maleic anhydride-modified polypropylene, and the crystallinity is controlled by setting different parameters in the processing technology to obtain maleic anhydride-modified polypropylene with the same material but different melting points.

[0059] Optionally, the heat-sealing welding layer is mainly composed of random copolymer polypropylene and terpolymer polypropylene materials, and a lubricant and an opening agent can be added thereto in consideration of formability. Usually, the random copolymer polypropylene material accounts for about 20-40%, the terpolymer polypropylene material accounts for about 50-80%, and the rest are auxiliary materials. In the embodiment, the increase in the melting point of the heat-sealing layer can be achieved by increasing the proportion of random copolymer polypropylene materials, and reducing it by increasing the proportion of terpolymer polypropylene. At the same time, increasing the proportion of auxiliary materials will increase the melting point of PP. The auxiliary materials include opening agents, elastomers, silica, and lubricants. Usually the proportion is less than 5%, and the lubricant can be erucamide and behenamide or a mixture of the two.

[0060] By setting different parameters in the processing technology to control the crystallinity, it is possible to obtain heat-sealing welding materials with the same material but different melting points.

[0061] Optionally, at least one side of the intermediate metal layer in contact with the inner heat seal layer is treated with an anti-corrosion treatment to form an inner passivation layer. Preferably, the side of the intermediate metal layer in contact with the outer substrate layer is also treated with an anti-corrosion treatment to form an outer passivation layer.

[0062] The specific treatment method is as follows: first, degreasing is performed on at least the inner side of the metal layer by using a treatment method such as alkaline immersion, electrolytic cleaning, acid cleaning, electrolytic acid cleaning or oxygen activation. Then, the passivation solution is applied by rod coating, roller coating, gravure coating or dipping, and a high-temperature chemical reaction is applied to the metal surface. The metal coated with the passivation solution is heat-treated at a high temperature of 210°C for 1-5 minutes to form an anti-corrosion layer. Specifically, the passivation solution mainly contains phosphoric acid, chromate, fluoride and rare earth oxide, etc. There are no special restrictions. In some embodiments of the present invention, chromate is used as the passivation solution, and its formula is, for example, 2-3%wt of chromium fluoride, 1-1.5%wt of polyester resin, and the rest is water.

[0063] Furthermore, the thickness of the passivation layer is extremely small and difficult to measure. Calculated based on the chromium content, the chromium content in the passivation layer is approximately 10 to 25 mg / m2.

[0064] Furthermore, in subsequent embodiments, a passivation liquid (2.5% wt chromium fluoride, 1% wt polyester resin, and the rest water) was evenly coated on both sides of the intermediate metal layer using a micro-concave coating method to form a passivation layer, and the chromium content of the passivation layer was 10-20 mg / ㎡.

[0065] Optionally, the material of the intermediate metal layer can be one of aluminum alloy (8021 / 8079, etc.), stainless steel, titanium steel, and nickel-plated iron plate, preferably an annealed O-state metal material.

[0066] The battery provided by the embodiment of the present invention adopts the battery packaging material as packaging.

[0067] Example

[0068] The parameter settings of each embodiment are shown in Table 1.

[0069] Table 1 Parameter settings of various embodiments

[0070]

[0071]

[0072] Comparative Example

[0073] The parameter settings of each comparative example are shown in Table 2.

[0074] Table 2 Parameter settings for each comparative example

[0075]

[0076]

[0077] Note: In Table 1 and Table 2, BOPET refers to biaxially stretched PET, GCPET refers to blown film PET; BOPA6 refers to biaxially stretched PA6, GCPA6 refers to blown film PA6;

[0078] 8021-O refers to 8021 aluminum alloy after annealing, 8021-H refers to 8021 aluminum alloy after cold work hardening, and 8021-semi-hard refers to 8021 aluminum alloy in a state between the annealed state (O) and the fully hard state (H). 8021 aluminum alloy can be annealed to achieve different strengths, elongations, and other properties. To achieve different properties from the same material, the intermediate metal layers in the above embodiments and comparative examples all use 8021 and are annealed to varying degrees to achieve different elongations and strengths.

[0079] The heat-seal adhesive layer is made of maleic anhydride-modified polypropylene. The reason why the melting points of some examples are different despite the same material is that the process parameters are adjusted during the extrusion process to change the crystallinity of the heat-seal adhesive layer and thus the melting point.

[0080] Except for Comparative Example 5, the heat-seal adhesive layer in each of the Examples and other Comparative Examples consisted of 29% random copolymer polypropylene, 1% lubricant (erucamide), 1% additive (PPS, polyphenylene sulfide), and the remainder terpolymer polypropylene. The slight difference in melting point between some Examples is due to adjustments to process parameters during the extrusion process that altered the crystallinity of the heat-seal adhesive layer, which in turn altered the melting point.

[0081] The material composition of the heat-sealing weld layer of Comparative Example 5 is 29% random copolymer polypropylene, 1% lubricant (erucamide), 1% additive (PPS, polyphenylene sulfide), 1% silicon dioxide and the balance ternary copolymer polypropylene.

[0082] Experimental example

[0083] The molding properties of the packaging materials of various embodiments and comparative examples were tested, and the test contents were as follows:

[0084] The molding test was conducted as follows: the mold was set to a rectangular parallelepiped shape (98mm (TD) by 57mm (MD) at various depths (with rounded corners); the gap between the male and female molds was 0.3mm, the corner R = 1.5mm, the edge R = 1.0mm, the surface roughness Ra = 0.8, the surface pressure was 10MPa, the core mold r = 1.5mm, the mold r = 2mm, the sample size was 58mm by 97mm, and the surface pressure was 10MPa. The molding depth was 10.5mm, and the judgment method was the light transmission method. After the test was completed, the sample was illuminated by a light source. If light transmission was observed from any part of the sample, the mold was considered to be broken. 100 samples were tested per group.

[0085] The heat seal strength test was performed using a heat sealer with a heat seal pressure of 1.0 MPa and a heat seal knife temperature of 190°C. The thickness of the PP layer after heat sealing was controlled to be 70% ± 5% of the thickness before heat sealing. A 15 mm wide sample was tested using an electronic universal tensile testing machine with a tensile rate of 5 mm / min and a chuck spacing of 50 mm. The maximum load during stretching was recorded as the heat seal strength.

[0086] In the battery packaging material molding test, the fewer the number of molding pinholes, the better. Fewer molding pinholes indicate better molding performance and yield at this molding depth. As can be seen in Table 1, within the preferred range of the present invention, each embodiment still maintained a very low number of pinholes under such a rigorous molding test of 10.5mm. Outside the preferred range, the breakage rate increased significantly, indicating that the packaging material provided by the preferred embodiment of the present invention outperforms existing conventional battery packaging materials.

[0087] In Comparative Examples 2, 3, 4, and 6, compared to Example 1, the ratio of the elongation of the first substrate layer to the second substrate layer in the same direction is greater or less than the range required by the present application. It can be seen that the number of molded pinholes is much greater than that in Example 1. This indicates that when the ratio of the elongation of the first substrate layer to the elongation of the second substrate layer is within the range required by the present invention, better moldability of the material can be ensured.

[0088] Comparing Example 7 with Example 1, Example 7 has significantly more pinholes, and the ratio of the elongation at break to the thickness of the intermediate metal layer in Example 7 is less than 0.25 compared to Example 1. This indicates that when this ratio is greater than 0.25, the formability of the packaging material can be better ensured.

[0089] Comparing Examples 8 and 9 with Example 1, the heat sealing strength of Examples 8 and 9 is inferior to that of Example 1, while the melting points of the heat-sealing adhesive layer and the heat-sealing weld layer of Examples 8 and 9 are lower than the preferred range required by the present invention. This indicates that when the melting points of the heat-sealing adhesive layer and the heat-sealing weld layer are within the preferred range of the present invention, the packaging material can better ensure good heat sealing strength.

[0090] It can be seen from Table 1 and Table 2 that the packaging materials provided by various embodiments of the present invention have good forming properties and better heat sealing.

[0091] Comparing each comparative example with the corresponding comparative example, the molding performance of each comparative example is significantly worse, which indicates that the elongation and ratio of each layer in the outer substrate layer should be within the range required by the present invention. If they are not within the range required by the present invention, the molding performance is significantly reduced.

[0092] In summary, the battery packaging material provided in the embodiments of the present invention, by limiting the elongation and elongation ratio of the two layers of the outer substrate layer to a specific range, can control the timing of the fracture of the two materials during the molding process to be close, thereby achieving the effect of improving the molding limit. A higher molding limit means that there is more molding margin compared to ordinary battery packaging, which can maintain better safety. The setting of the specific elongation and elongation ratio can also improve the corrosion resistance to the electrolyte, which can achieve the purpose of increasing the energy density of the battery within a certain safety range.

[0093] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A battery packaging material, characterized in that: It includes an outer base material layer, an intermediate metal layer and an inner heat-sealing layer arranged in sequence; The outer substrate layer includes a first substrate layer and a second substrate layer closer to the intermediate metal layer than the first substrate layer; The ratio of the elongation of the first substrate layer to that of the second substrate layer in the same direction is (0.85-1.1):

1.

2. The battery packaging material according to claim 1, characterized in that The ratio of the elongation of the first substrate layer to the second substrate layer in the MD direction is (0.85-1.09):1, and the ratio in the TD direction is (0.85-1.1):

1.

3. The battery packaging material according to claim 1, characterized in that The elongation of the first substrate layer in the MD direction is 110% to 140%; the elongation of the second substrate layer in the MD direction is 100% to 130%; Preferably, the elongation of the first substrate layer in the MD direction is 104-125%, and the elongation of the second substrate layer in the MD direction is 110-128%.

4. The battery packaging material according to claim 1, characterized in that The ratio of the elongation of the first substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1); the ratio of the elongation of the second substrate layer in the MD direction to the elongation in the TD direction is 1:(0.6-1.1); Preferably, the ratio of the elongation of the first substrate layer in the MD direction to the elongation in the TD direction is 1:(0.72-0.98); the ratio of the elongation of the second substrate layer in the MD direction to the elongation in the TD direction is 1:(0.74-0.98).

5. The battery packaging material according to claim 1, characterized in that The ratio of the thickness of the first substrate layer to the second substrate layer is (0.5-1.1):1; Preferably, the thickness ratio of the first substrate layer to the second substrate layer is (0.667-1):

1.

6. The battery packaging material according to claim 1, characterized in that Calculated in terms of elongation at break (unit: %) and thickness (unit: μm), the ratio of the elongation at break of the intermediate metal layer to its thickness is greater than 0.

25.

7. The battery packaging material according to claim 1, characterized in that The inner heat-sealing layer comprises a composite heat-sealing adhesive layer and a heat-sealing welding layer.

8. The battery packaging material according to claim 7, characterized in that: The melting temperature of the heat-sealing adhesive layer is 138.6-145°C, and the melting temperature of the heat-sealing welding layer is 153-160°C; Preferably, the melting temperature of the heat-sealing adhesive layer is 138.6-144.6°C, and the melting temperature of the heat-sealing weld layer is 153.3-158.9°C.

9. The battery packaging material according to claim 1, characterized in that The side of the intermediate metal layer in contact with the inner heat-sealing layer is subjected to anti-corrosion treatment to form an inner passivation layer; The side of the intermediate metal layer in contact with the outer base material layer is subjected to anti-corrosion treatment to form an outer passivation layer.

10. A battery, characterized in that: The battery packaging material according to any one of claims 1 to 9 is used as packaging.

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