Battery casing material and method for manufacturing battery casing material

Abstract

The present invention provides an exterior material for batteries that suppresses thermal displacement during heat sealing while maintaining seal strength. [Solution] The battery casing material 10 comprises a barrier layer 30, an electron beam crosslinked layer 40 on the barrier layer 30, and a sealing layer 50 on the electron beam crosslinked layer 40. The electron beam crosslinked layer 40 includes at least one layer of electron beam crosslinked polyethylene resin. The sealing layer 50 includes at least one layer of non-electron beam crosslinked polyethylene resin.

Description

Technical Field

[0001] The present invention relates to a battery outer packaging material and a method for producing a battery outer packaging material. Background Art

[0002] Development of lithium ion secondary batteries and all-solid-state batteries is underway. Such batteries are provided with an outer packaging material that encloses a positive electrode material and a negative electrode material. The following Patent Document 1 discloses an outer packaging material (packaging material) for a lithium ion battery. The battery body is accommodated inside the outer packaging material by heat-sealing the peripheral edge of the outer packaging material.

[0003] The outer packaging material described in Patent Document 1 includes at least a base material layer, an adhesive layer, a chemical conversion treatment layer, aluminum (barrier layer), a chemical conversion treatment layer, an adhesive layer, and a heat-seal layer in this order in the thickness direction thereof. The heat-seal layer includes at least an electron beam-crosslinked polyolefin layer. Electron beam-crosslinked polyolefin is excellent in heat resistance. Therefore, Patent Document 1 describes that when heat-sealing an outer package, the film shape of the heat-seal layer is maintained, and there is no risk of electrical short-circuiting between the aluminum in the outer packaging material and the metal tab of the battery. Prior Art Literature Patent Literature

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2002-245982 Summary of the Invention Problem to be Solved by the Invention

[0005] As described in Patent Document 1, if the heat resistance of the exterior material is low, there is a risk that the barrier layer (a metal such as aluminum) in the exterior material will short-circuit with the metal tab of the battery. On the other hand, the inventors of the present application have found that when the heat seal layer consists of an electron beam crosslinked polyolefin layer, the electron beam crosslinked polyolefin layer has excellent heat resistance, so the seal strength of the heat-sealed portion may not be sufficiently maintained.

[0006] Therefore, there is a need for a battery casing material and a method for manufacturing a battery casing material that can suppress thermal displacement during heat sealing while maintaining seal strength. [Means for solving the problem]

[0007] An exterior material for a battery according to one embodiment comprises a barrier layer, an electron beam crosslinked layer on the barrier layer, and a sealing layer on the electron beam crosslinked layer. The electron beam crosslinked layer comprises at least one layer of electron beam crosslinked polyethylene resin. The sealing layer comprises at least one layer of non-electron beam crosslinked polyethylene resin.

[0008] A battery according to one embodiment comprises the above-mentioned outer casing material for the battery and an electrode material encased by the outer casing material.

[0009] A method for manufacturing an outer casing material for a battery according to one embodiment includes the steps of: irradiating at least one layer of polyethylene resin laminated on a barrier layer with an electron beam to form an electron beam crosslinked layer; and laminating at least one layer of non-electron beam crosslinked polyethylene resin on the electron beam crosslinked layer to form a seal layer. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view of a part of the exterior material for a battery according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing one step in the manufacturing method of a battery casing material according to the first embodiment. [Figure 3]Figure 3 is a schematic cross-sectional view showing the steps following Figure 2. [Figure 4] Figure 4 is a schematic cross-sectional view showing the steps following Figure 3. [Figure 5] Figure 5 is a schematic cross-sectional view showing the steps following Figure 4. [Figure 6] Figure 6 is a schematic cross-sectional view of a part of the exterior material for a battery according to the second embodiment. [Figure 7] Figure 7 is a schematic cross-sectional view of a part of the battery casing material according to the third embodiment. [Figure 8] Figure 8 is a schematic perspective view of a battery, including its exterior materials. [Modes for carrying out the invention]

[0011] The embodiments will be described below with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the proportions of the dimensions, etc., may differ from those of reality.

[0012] [First Embodiment] The exterior material for the battery according to the first embodiment will be described with reference to the figures. Figure 1 is a schematic cross-sectional view of a part of the exterior material for the battery according to the first embodiment. Specifically, Figure 1 shows a cross-section of a part of the exterior material 10 when only the portion of the exterior material 10 is cut along line AA in the battery 100 shown in Figure 8.

[0013] The outer casing material 10 may be an outer casing material for enclosing a battery body, such as a lithium-ion battery or an all-solid-state battery. The outer casing material 10 may be a laminate film in which multiple layers are stacked on top of each other.

[0014] The exterior material 10 may include at least a barrier layer 30, an electron beam crosslinked layer 40 on the barrier layer 30, and a seal layer 50 on the electron beam crosslinked layer 40. Preferably, the exterior material 10 may include a base material layer 20, an adhesive layer 22, a chemical conversion treatment layer 32, a barrier layer 30, a chemical conversion treatment layer 34, an electron beam crosslinked layer 40, and a seal layer 50 in this order.

[0015] The electron beam crosslinked layer 40 includes at least one layer of electron beam crosslinked polyethylene resin. The seal layer 50 includes at least one layer of non-electron beam crosslinked polyethylene resin. When packaging an electrode material of a battery, for example, in a state where the seal layers 50 of two sheets of the exterior material 10 face each other, or in a state where one sheet of the exterior material 10 is folded such that the seal layer 50 faces itself, the seal layers 50 are heat-welded (heat-sealed) to each other.

[0016] Here, since the seal layer 50 contains non-electron beam crosslinked polyethylene resin, it is easily melted by heating. Accordingly, adhesiveness by heat sealing is improved. Furthermore, since the electron beam crosslinked layer 40 contains electron beam crosslinked polyethylene resin, the electron beam crosslinked layer 40 has high heat resistance and is less prone to thermal displacement. Therefore, even if the thermal displacement of the seal layer 50 is large, the thermal displacement of the entire exterior material 10 is suppressed by the electron beam crosslinked layer 40. Accordingly, an exterior material 10 for a battery that can suppress thermal displacement during heat sealing and maintain seal strength can be obtained.

[0017] In a state where the exterior material 10 is used, that is, in a state where the exterior material 10 encloses an electrode material of a battery, the base material layer 20 faces the outer surface of the battery. The material constituting the base material layer 20 is not particularly limited. Preferably, the base material layer 20 is formed of an insulating resin layer. The base material layer 20 may be composed of one resin layer, or may be composed of a plurality of resin layers.

[0018] In one example, the base layer 20 may include a polyester film or a nylon film. Preferably, the base layer 20 has a melting point equal to or greater than the melting point of the nylon film. The base layer 20 is made of, for example, polyester or nylon film. The base layer 20 may be bonded to the barrier layer 30, which will be described later, via an adhesive layer 22. If a chemical treatment layer 32 is present, the base layer 20 may be bonded to the chemical treatment layer 32 on the barrier layer 30 via the adhesive layer 22.

[0019] The thickness of the substrate layer 20 may be, for example, 1 μm to 60 μm, preferably 2 μm to 40 μm, more preferably 3 μm to 30 μm, and even more preferably 5 μm to 20 μm.

[0020] The base layer 20 should have sufficient thickness so that the metal material constituting the barrier layer 30 does not electrically short-circuit with any member installed on the outside of the exterior material. The lower limit of the thickness of the base layer 20 should be set from this viewpoint. On the other hand, from the viewpoint of preventing the thickness of the exterior material 10 from becoming excessively large, it is preferable that the thickness of the base layer 20 be smaller than the desired value, as described above.

[0021] The barrier layer 30 may be provided to suppress the passage of gas through the exterior material 10. The material constituting the barrier layer 30 is not particularly limited as long as it is a material capable of achieving relatively low gas permeability. Preferably, the material constituting the barrier layer 30 is a metallic material. The barrier layer 30 may contain, for example, aluminum, nickel, or alumina, or a combination thereof.

[0022] The barrier layer 30 preferably has sufficient thickness to prevent gas from permeating to a desired extent. On the other hand, in order to prevent the thickness of the exterior material 10 from becoming excessively large, the thickness of the barrier layer 30 is preferably smaller than the desired value. From this viewpoint, the thickness of the barrier layer 30 may be, for example, 2 μm to 100 μm, preferably 5 μm to 60 μm, more preferably 8 μm to 40 μm, and even more preferably 10 μm to 30 μm.

[0023] The exterior material 10 may have chemical conversion treatment layers 32 and 34 on at least one surface, preferably both surfaces, of the barrier layer 30. The chemical conversion treatment layers 32 and 34 may be acid-resistant coatings formed on the surface of the material constituting the barrier layer 30, particularly metal materials. Specifically, the chemical conversion treatment layers 32 and 34 are formed by forming acid-resistant coatings such as phosphates, chromates, fluorides, and triazinethiol compounds on the surface of the material constituting the barrier layer 30. This suppresses the dissolution and corrosion of the material constituting the barrier layer 30.

[0024] The chemical treatment layers 32 and 34 may be provided as desired. That is, one or both of the chemical treatment layers 32 and 34 may not be provided.

[0025] In the first embodiment, the electron beam crosslinked layer 40 comprises at least two layers of electron beam crosslinked polyethylene resin. Specifically, the electron beam crosslinked layer 40 may have an adhesive layer 44 bonded to the barrier layer 30 or the chemical treatment layer 34 on the barrier layer 30, and a first intermediate layer 42 located between the adhesive layer 44 and the seal layer 50.

[0026] If the exterior material 10 does not include the chemical treatment layer 34, the adhesive layer 44 is bonded to the barrier layer 30. If the exterior material 10 includes the chemical treatment layer 34, the adhesive layer 44 is bonded to the chemical treatment layer 34.

[0027] The adhesive layer 44 may contain polyethylene resin. Preferably, the adhesive layer 44 contains electron beam crosslinked polyethylene resin. The inclusion of electron beam crosslinked polyethylene resin in the adhesive layer 44 improves the heat resistance of the exterior material 10.

[0028] More preferably, the adhesive layer 44 contains an electron beam crosslinked acid-modified polyethylene resin. Acid modification of the polyethylene resin improves its adhesion to the barrier layer 30 or the chemical conversion treatment layer 34.

[0029] Preferably, the density of the polyethylene resin constituting the adhesive layer 44 is less than the density of the polyethylene resin contained in at least one of the first intermediate layer 42 (described later) and the second intermediate layer 54 of the sealing layer 50 (described later). More preferably, the density of the polyethylene resin constituting the adhesive layer 44 is less than the density of the polyethylene resin contained in both the first intermediate layer 42 (described later) and the second intermediate layer 54 of the sealing layer 50 (described later).

[0030] The density of the polyethylene resin constituting the adhesive layer 44 is not particularly limited. Preferably, the density of the polyethylene resin constituting the adhesive layer 44 is 0.90 to 0.94 kg / m³. 3 It may be within that range.

[0031] The gel fraction of the polyethylene resin constituting the adhesive layer 44 may be in the range of 10% to 80%, preferably 30% to 80%, and more preferably 50% to 80%. Here, the gel fraction is an indicator of the degree of crosslinking of the resin. By having the gel fraction within the above range, the exterior material 10, specifically the adhesive layer 44, will have more sufficient heat resistance against the heat generated during heat sealing of the seal layer 50.

[0032] The thickness of the adhesive layer 44 may be, for example, in the range of 3 μm to 10 μm, preferably 4 μm to 8 μm, and more preferably 5 μm to 7 μm.

[0033] The first intermediate layer 42 includes at least one layer of electron-beam crosslinked polyethylene resin. From the viewpoint of heat resistance of the exterior material, the first intermediate layer 42 may include multiple layers of electron-beam crosslinked polyethylene resin. Alternatively, from the viewpoint of reducing the thickness of the exterior material 10, it is preferable that the first intermediate layer 42 includes one layer of electron-beam crosslinked polyethylene resin. In Figure 1, as an example, the first intermediate layer 42 includes one layer of electron-beam crosslinked polyethylene resin.

[0034] The heat resistance of the exterior material 10 is improved by including electron beam crosslinked polyethylene resin in the first intermediate layer 42. Preferably, the density of the polyethylene resin constituting the first intermediate layer 42 is greater than the density of the polyethylene resin contained in the inner surface layer 52 of the seal layer 50, which will be described later. As a result, the heat resistance of the first intermediate layer 42 is further improved, and the overall heat resistance of the exterior material 10 may be improved.

[0035] The density of the polyethylene resin constituting the first intermediate layer 42 is not particularly limited. Preferably, the density of the polyethylene resin constituting the first intermediate layer 42 is, for example, 0.90 to 0.98 kg / m³. 3 Preferably 0.92-0.98 kg / m 3 , more preferably 0.94~0.98 kg / m 3 It may be within that range.

[0036] The first intermediate layer 42 may be provided such that the exterior material 10 has sufficient heat resistance. From this viewpoint, the density of the polyethylene resin constituting the first intermediate layer 42 is more preferably 0.94 to 0.98 kg / m³. 3 It may be within that range.

[0037] The gel fraction of the polyethylene resin constituting the first intermediate layer 42 may be in the range of 10% to 80%, preferably 30% to 80%, and more preferably 50% to 80%.

[0038] The first intermediate layer 42 may be provided so that the exterior material 10 has sufficient heat resistance. On the other hand, in order to prevent the thickness of the exterior material 10 from becoming excessively large, it is preferable that the thickness of the first intermediate layer 42 be smaller than the desired value. In this regard, the thickness of the first intermediate layer 42 may be in the range of, for example, 3 μm to 10 μm, preferably 4 μm to 8 μm, and more preferably 5 μm to 7 μm.

[0039] The overall thickness of the electron beam crosslinked layer 40 may be, for example, 6 μm to 20 μm, preferably 8 μm to 16 μm, and more preferably 10 μm to 14 μm.

[0040] In the first embodiment, the seal layer 50 comprises at least two layers of non-electron beam crosslinked polyethylene resin. Specifically, the seal layer 50 may have an inner surface layer 52 comprising non-electron beam crosslinked polyethylene resin, and a second intermediate layer 54 located between the inner surface layer 52 and the electron beam crosslinked layer 40, comprising non-electron beam crosslinked polyethylene resin.

[0041] Preferably, the density of the polyethylene resin contained in the second intermediate layer 54 may be greater than or equal to the density of the polyethylene resin contained in the inner surface layer 52. More preferably, the density of the polyethylene resin contained in the second intermediate layer 54 is greater than the density of the polyethylene resin contained in the inner surface layer 52.

[0042] In this case, if the seal layer 50 consists only of a single layer of non-electron beam crosslinked polyethylene resin, the innermost surface of the seal layer 50 (the surface being heat-sealed) is directly adjacent to a highly heat-resistant layer (electron beam crosslinked layer 40). As a result, the portion of the exterior material 10 directly above the seal layer 50 is less susceptible to thermal displacement, which can prevent sufficient heat sealing (and thus prevent adequate sealing strength).

[0043] In the first embodiment, a second intermediate layer 54 is provided on the surface of the exterior material 10 on the side of the seal layer 50, that is, adjacent to the inner surface layer 52 of the seal layer 50. As described above, the second intermediate layer 54 has a polyethylene resin with a density greater than or equal to that of the polyethylene resin contained in the inner surface layer 52. As a result, the inner surface layer 52 is more susceptible to thermal displacement than the electron beam crosslinked layer 40 and forms a layer with higher heat resistance than the inner surface layer 52. Therefore, the second intermediate layer 54 is considered to play a buffering role between the inner surface layer 52 and the electron beam crosslinked layer 40. This makes it possible to provide an exterior material 10 for batteries that can suppress thermal displacement during heat sealing and maintain sufficient seal strength.

[0044] The density of the polyethylene resin constituting the inner surface layer 52 is, for example, 0.90 to 0.94 kg / m³. 3It may be within this range. On the other hand, the density of the polyethylene resin constituting the second intermediate layer 54 is, for example, 0.94 to 0.98 kg / m³. 3 It may be within that range.

[0045] From the standpoint of ensuring heat sealability, it is preferable that the thickness of the inner surface layer 52 and the first intermediate layer 54 be greater than the desired value. On the other hand, from the standpoint of not making the thickness of the exterior material 10 excessively large, it is preferable that the thickness of the inner surface layer 52 and the first intermediate layer 54 be smaller than the desired value.

[0046] From this perspective, the thickness of the inner surface layer 52 may be in the range of, for example, 3 μm to 10 μm, preferably 4 μm to 8 μm, and more preferably 5 μm to 7 μm. The thickness of the second intermediate layer 54 may be in the range of, for example, 3 μm to 10 μm, preferably 4 μm to 8 μm, and more preferably 3 μm to 10 μm.

[0047] Furthermore, the overall thickness of the sealing layer 50 may be, for example, 6 μm to 20 μm, preferably 8 μm to 16 μm, and more preferably 10 μm to 14 μm.

[0048] In recent years, the increasing capacity of batteries has led to a demand for thinner batteries. From this perspective, thinning of the outer casing material 10 is also required. Polyethylene resin has the advantage of being relatively easy to thin. Furthermore, polyethylene resin has the advantage of being easily crosslinked by electron beam irradiation. On the other hand, if crosslinking by electron beam irradiation is not performed, polyethylene resin also has the advantage of high sealing properties by heat sealing.

[0049] Furthermore, in the first embodiment, from the viewpoint of thinning the electron beam crosslinking layer 40, it is desirable that the electron beam crosslinking layer 40 comprises only two layers: one adhesive layer 44 and one first intermediate layer 42. Similarly, from the viewpoint of thinning the seal layer 50, it is desirable that the seal layer 50 comprises only two layers: one inner surface layer 54 and one second intermediate layer 52. However, it should be noted that the present invention is not limited thereto.

[0050] Furthermore, even when the exterior material 10 having the above-described laminated structure is made into a thin film as described above, it is possible to suppress thermal displacement during heat sealing of the exterior material 10 and maintain the sealing strength of the exterior material 10, which is considered to be an advantage.

[0051] Next, a method for manufacturing a battery casing according to the first embodiment will be described with reference to Figures 2 to 5. Figure 2 is a schematic cross-sectional view showing one step of the method for manufacturing a battery casing according to the first embodiment. Figure 3 is a schematic cross-sectional view showing a step following Figure 2. Figure 4 is a schematic cross-sectional view showing a step following Figure 3. Figure 5 is a schematic cross-sectional view showing a step following Figure 4.

[0052] In the manufacturing method for battery casing materials, first, a barrier layer 30 is prepared (see Figure 2). The materials and thickness of the barrier layer 30 are as described above.

[0053] Next, optionally, chemical conversion treatment layers 32 and 34 are formed on at least one, preferably both, surfaces of the materials constituting the barrier layer 30. The chemical conversion treatment may be a treatment that forms an acid-resistant film on at least one, preferably both, surfaces of the materials constituting the barrier layer 30 by any method.

[0054] Next, at least one sheet of polyethylene resin that will become the electron beam crosslinked layer 40 is prepared (see Figure 2). Note that at this point, the polyethylene resin sheet has not yet been electron beam crosslinked. The polyethylene resin sheet that will become the electron beam crosslinked layer 40 is laminated on the barrier layer 30, for example, by a heat lamination method.

[0055] In the first embodiment, the resin sheet to become the electron beam crosslinked layer 40 includes a polyethylene resin layer to constitute the first intermediate layer 42 and a polyethylene resin layer to constitute the adhesive layer 44. The thickness, density, and other configurations of the polyethylene resin layers to constitute the first intermediate layer 42 and the adhesive layer 44 are as described above. The resin sheet to become the electron beam crosslinked layer 40 adheres the electron beam crosslinked layer 40 to the barrier layer 30 via the adhesive layer 44.

[0056] The resin sheet that will become the electron beam crosslinking layer 40 is laminated adjacent to the chemical conversion treatment layer 34 if the chemical conversion treatment layer 34 is present. The resin sheet that will become the electron beam crosslinking layer 40 is laminated adjacent to the barrier layer 30 if the chemical conversion treatment layer 34 is not present.

[0057] Next, the polyethylene resin laminated on the barrier layer 30 is irradiated with an electron beam to form an electron beam crosslinked layer 40 (see Figure 3). This forms an electron beam crosslinked layer 40 including the first intermediate layer 42 and the adhesive layer 44.

[0058] The electron beam irradiation conditions can be selected as appropriate. For example, the acceleration voltage during electron beam irradiation may be in the range of 30 to 280 kV. For example, the electron beam dose may be in the range of 30 to 350 kGy.

[0059] Next, at least one layer of non-electron-beam crosslinked polyethylene resin is laminated on the electron-beam crosslinked layer 40 to form a seal layer 50 (see Figure 4). In the first embodiment, the seal layer 50 includes a second intermediate layer 52 and an inner surface layer 54. The thickness, density, and other configurations of the polyethylene resin layers that constitute the second intermediate layer 52 and the inner surface layer 54 are as described above. The seal layer 50 is laminated on the electron-beam crosslinked layer 40, for example, by a heat lamination method.

[0060] Next, the base layer 20 is laminated on the side of the barrier layer 30 opposite to the seal layer 50 (see Figure 5). If the chemical treatment layer 32 is present, the base layer 20 is laminated adjacent to the chemical treatment layer 32. If the chemical treatment layer 32 is not present, the base layer 20 is laminated adjacent to the barrier layer 30. The base layer 20 is laminated on the barrier layer 30 by bonding, for example, by dry lamination via the adhesive layer 22. The materials and thickness of the base layer 20 are as described above.

[0061] The exterior material 10 is obtained through the process described above. In the manufacturing method described above, the resin sheet that is to become the electron beam crosslinked layer 40 is laminated on the barrier layer 30 and then crosslinked with an electron beam. Alternatively, the resin sheet that is to become the electron beam crosslinked layer 40 may be crosslinked with an electron beam and then laminated on the barrier layer 30.

[0062] Furthermore, the above process mentions heat lamination as an example of a method for laminating each layer. Alternatively, if possible, the lamination method for each layer may be extrusion lamination. From the perspective of preparing the resin sheets that will become the electron beam crosslinking layer 40 and the resin sheets that will become the sealing layer 50 in advance and then laminating them together, applying heat lamination is more preferable.

[0063] [Second Embodiment] The battery casing material according to the second embodiment will be described with reference to the figures. Figure 6 is a schematic cross-sectional view of a part of the battery casing material according to the second embodiment. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment. Also, please note that the description of components that are the same as in the first embodiment may be omitted.

[0064] The exterior material 10 according to the second embodiment may have at least a barrier layer 30, an electron beam crosslinking layer 40 on the barrier layer 30, and a sealing layer 50 on the electron beam crosslinking layer 40. The exterior material 10 according to the second embodiment is the same as the first embodiment, except for the structure of the electron beam crosslinking layer 40.

[0065] In the second embodiment, the electron beam crosslinking layer 40 may have an adhesive layer 44 that is bonded to the barrier layer 30 or the chemical conversion treatment layer 34 on the barrier layer 30. The first intermediate layer 42 described in the first embodiment may not be provided.

[0066] The adhesive layer 44 may contain polyethylene resin. Preferably, the adhesive layer 44 contains electron beam crosslinked polyethylene resin. More preferably, the adhesive layer 44 contains electron beam crosslinked acid-modified polyethylene resin.

[0067] The density of the polyethylene resin constituting the adhesive layer 44 is preferably less than the density of the polyethylene resin contained in the second intermediate layer 54 of the seal layer 50. The density and gel fraction of the polyethylene resin constituting the adhesive layer 44 are as described in the first embodiment.

[0068] The thickness of the adhesive layer 44 may be, for example, in the range of 6 μm to 20 μm, preferably 8 μm to 16 μm, and more preferably 10 μm to 14 μm.

[0069] In the second embodiment, the electron beam crosslinking layer 40 for improving the heat resistance of the exterior material 10 is composed only of an adhesive layer 44 that is bonded to the barrier layer 30 or the chemical conversion treatment layer 34 on the barrier layer 30. This provides the advantage of simplifying the structure of the exterior material 10.

[0070] In the second embodiment, the seal layer 50 is configured similarly to the first embodiment, including at least two layers of uncrosslinked polyethylene resin. Therefore, similar to the first embodiment, it is possible to provide a battery exterior material 10 that suppresses thermal displacement during heat sealing while maintaining sufficient seal strength.

[0071] The exterior material 10 according to the second embodiment can be manufactured in the same manner as the exterior material 10 according to the first embodiment. Specifically, the exterior material 10 according to the second embodiment has the same configuration as the exterior material 10 according to the first embodiment, except that the number of layers of the material constituting the electron beam crosslinking layer 40 is different. Therefore, the manufacturing method of the exterior material 10 according to the second embodiment is the same as that of the first embodiment, except that the number of layers constituting the resin sheet that will become the electron beam crosslinking layer 40 is changed to match the second embodiment.

[0072] [Third Embodiment] The battery casing material according to the third embodiment will be described with reference to the figures. Figure 7 is a schematic cross-sectional view of a part of the battery casing material according to the third embodiment. In the third embodiment, the same reference numerals are used for components similar to those in the first embodiment. It should also be noted that the description of components similar to those in the first embodiment may be omitted.

[0073] The exterior material 10 according to the third embodiment may have at least a barrier layer 30, an electron beam crosslinking layer 40 on the barrier layer 30, and a sealing layer 50 on the electron beam crosslinking layer 40. The exterior material 10 according to the third embodiment is the same as the first embodiment, except for the structure of the sealing layer 50.

[0074] In the third embodiment, the seal layer 50 includes one layer of non-electron beam crosslinked polyethylene resin. Specifically, the seal layer 50 includes only an inner surface layer 52 containing non-electron beam crosslinked polyethylene resin. The second intermediate layer 54 described in the first embodiment may not be provided. The density of the polyethylene resin constituting the inner surface layer 52 is as described in the first embodiment.

[0075] From the viewpoint of ensuring heat sealability, it is preferable that the thickness of the inner surface layer 52 be greater than the desired value. On the other hand, from the viewpoint of not making the thickness of the exterior material 10 excessively large, it is preferable that the thickness of the inner surface layer 52 be smaller than the desired value. From this viewpoint, the thickness of the inner surface layer 52 may be in the range of, for example, 3 μm to 10 μm, preferably 4 μm to 8 μm, and more preferably 5 μm to 7 μm.

[0076] The exterior material 10 according to the third embodiment can be manufactured in the same manner as the exterior material 10 according to the first embodiment. Specifically, the exterior material 10 according to the third embodiment has the same configuration as the exterior material 10 according to the first embodiment, except that the number of layers of the material constituting the seal layer 50 is different. Therefore, the manufacturing method of the exterior material 10 according to the third embodiment is the same as that of the first embodiment, except that the number of layers constituting the resin sheet that will become the seal layer 50 is changed to match the third embodiment.

[0077] The exterior material 10 according to the third embodiment has an electron beam crosslinked layer 40 and a non-electron beam crosslinked sealing layer 50. Therefore, the sealing strength is higher compared to an exterior material in which all layers on the sealing layer side of the barrier layer are electron beam crosslinked. Also, compared to an exterior material in which all layers on the sealing layer side of the barrier layer are not electron beam crosslinked, thermal displacement during heat sealing can be suppressed.

[0078] However, in order to further suppress thermal displacement during heat sealing and to maintain seal strength more sufficiently, it is more preferable that the seal layer 50 includes the aforementioned second intermediate layer 54 together with the inner surface layer 52, as described in the first and second embodiments.

[0079] The exterior material 10 described in the first to third embodiments can be suitably used as an exterior material for a battery. Figure 8 is a schematic perspective view of a battery including the exterior material. The battery 100 may have the aforementioned exterior material 10 and an electrode material (not shown) encased by the exterior material 10. The battery 100 may have a pair of tab leads 120. Each tab lead 120 is electrically connected to an electrode material (not shown) encased by the exterior material 10.

[0080] The exterior material 10 may be in the form of a bag. The region R shown in Figure 8 (the region filled with dots) indicates the region where the sealing layers 50 of opposing exterior materials 10 are heat-sealed together. Note that the heat-sealed region is not limited to the configuration shown in Figure 8, as long as it can make the inside of the bag-shaped exterior material 10 airtight and / or liquid-tight.

[0081] [Example of experiment] (Example 1) The exterior material in Example 1 will now be described. The laminated structure of the exterior material 10 in Example 1 is as shown in Figure 1 (First Embodiment). Specifically, the exterior material 10 includes, in this order, a base layer 20, an adhesive layer 22, a chemical conversion treatment layer 32, a barrier layer 30, a chemical conversion treatment layer 34, an adhesive layer 44 and a first intermediate layer 42 (electron beam crosslinked layer 40), and a second intermediate layer 52 and an inner surface layer 54 (seal layer 50). The exterior material in Example 1 was manufactured by the method described in the First Embodiment.

[0082] The base layer 20 is a nylon film with a thickness of 15 μm. The barrier layer 30 is aluminum foil with a thickness of 20 μm. The chemical treatment layers 32 and 34 were formed by treating both sides of the aluminum foil with a trivalent chromate treatment agent.

[0083] The thicknesses of the adhesive layer 44, the first intermediate layer 42, the second intermediate layer 52, and the inner surface layer 54 are shown in Table 1 below. The types and densities of the resins constituting the adhesive layer 44, the first intermediate layer 42, the second intermediate layer 52, and the inner surface layer 54 are also shown in Table 1 below. Table 1 also indicates whether or not the resins constituting the adhesive layer 44, the first intermediate layer 42, the second intermediate layer 52, and the inner surface layer 54 are electron beam crosslinked.

[0084] Regarding the resin types in Table 1, "Acid-modified L-LDPE" refers to acid-modified linear low-density polyethylene resin. "L-LDPE" refers to linear low-density polyethylene resin. "LDPE" refers to low-density polyethylene resin. "HDPE" refers to high-density polyethylene resin.

[0085] (Example 2) The exterior material in Example 2 will now be described. The exterior material 10 in Example 2 is the same as in Example 1, except for the resins that make up the first intermediate layer 42 and the second intermediate layer 52. In Example 2, the resins that make up the first intermediate layer 42 and the second intermediate layer 52 are polyethylene resins, and the density of these resins is different from that in Example 1. Please also refer to Table 1 for the composition of each layer.

[0086] (Example 3) The exterior material in Example 3 will now be described. The exterior material 10 in Example 3 is the same as in Example 1, except for the resins that make up the first intermediate layer 42 and the second intermediate layer 52. In Example 3, the resins that make up the first intermediate layer 42 and the second intermediate layer 52 are polyethylene resins, and the density of these resins is different from that in Example 1. Please also refer to Table 1 for the composition of each layer.

[0087] (Example 4) The exterior material in Example 4 will now be described. The laminated structure of the exterior material 10 in Example 4 is as shown in Figure 6 (Second Embodiment). Specifically, the exterior material 10 in Example 4 includes, in this order, a base layer 20, an adhesive layer 22, a chemical conversion treatment layer 32, a barrier layer 30, a chemical conversion treatment layer 34, an adhesive layer 44 (electron beam crosslinked layer 40), a second intermediate layer 52, and an inner surface layer 54 (seal layer 50).

[0088] The materials and thicknesses of the base layer 20, adhesive layer 22, chemical treatment layer 32, barrier layer 30, and chemical treatment layer 34 are the same as in Example 1.

[0089] The thicknesses of the adhesive layer 44, the second intermediate layer 52, and the inner surface layer 54 are shown in Table 1 below. The types and densities of the resins constituting the adhesive layer 44, the second intermediate layer 52, and the inner surface layer 54 are also shown in Table 1 below. Table 1 also indicates whether or not the resins constituting the adhesive layer 44, the second intermediate layer 52, and the inner surface layer 54 are electron beam crosslinked.

[0090] (Example 5) The exterior material in Example 5 will now be described. The laminated structure of the exterior material 10 in Example 5 is as shown in Figure 7 (Third Embodiment). Specifically, the exterior material 10 includes, in this order, a base layer 20, an adhesive layer 22, a chemical conversion treatment layer 32, a barrier layer 30, a chemical conversion treatment layer 34, an adhesive layer 44 and a first intermediate layer 42 (electron beam crosslinked layer 40), and an inner surface layer 54 (seal layer 50).

[0091] The materials and thicknesses of the base layer 20, adhesive layer 22, chemical treatment layer 32, barrier layer 30, and chemical treatment layer 34 are the same as in Example 1.

[0092] The thicknesses of the adhesive layer 44, the first intermediate layer 42, and the inner surface layer 54 are shown in Table 1 below. The types and densities of the resins constituting the adhesive layer 44, the first intermediate layer 42, and the inner surface layer 54 are also shown in Table 1 below. Table 1 also indicates whether or not the resins constituting the adhesive layer 44, the first intermediate layer 42, and the inner surface layer 54 are electron beam crosslinked.

[0093] (Reference example 1) The exterior material in Reference Example 1 will now be described. The exterior material in Reference Example 1 includes, in this order, a base layer, an adhesive layer, a chemical treatment layer, a barrier layer, a chemical treatment layer, an adhesive layer, a first intermediate layer, a second intermediate layer, and an inner surface layer. The base layer, adhesive layer, chemical treatment layer, barrier layer, and chemical treatment layer in Reference Example 1 are the same as the base layer 20, adhesive layer 22, chemical treatment layer 32, barrier layer 30, and chemical treatment layer 34 in Example 1, respectively.

[0094] The thicknesses of the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer in Reference Example 1 are shown in Table 1 below. Furthermore, the types and densities of the resins constituting the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer in Reference Example 1 are also shown in Table 1 below.

[0095] In Reference Example 1, all polyethylene resins in the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer are electron beam crosslinked (see also Table 1). In other words, in Reference Example 1, all layers on the sealing layer side of the barrier layer are electron beam crosslinked.

[0096] (Reference example 2) The exterior material in Reference Example 2 will now be described. The exterior material in Reference Example 2 includes, in this order, a base layer, an adhesive layer, a chemical treatment layer, a barrier layer, a chemical treatment layer, an adhesive layer, a first intermediate layer, a second intermediate layer, and an inner surface layer. The base layer, adhesive layer, chemical treatment layer, barrier layer, and chemical treatment layer in Reference Example 2 are the same as the base layer 20, adhesive layer 22, chemical treatment layer 32, barrier layer 30, and chemical treatment layer 34 in Example 1, respectively.

[0097] The thicknesses of the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer in Reference Example 2 are shown in Table 1 below. Furthermore, the types and densities of the resins constituting the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer in Reference Example 2 are also shown in Table 1 below.

[0098] In Reference Example 2, all polyethylene resins in the adhesive layer, first intermediate layer, second intermediate layer, and inner surface layer are not electron beam crosslinked (see also Table 1). In other words, in Reference Example 2, all layers on the sealing layer side of the barrier layer are not electron beam crosslinked.

[0099] (Experimental methods and experimental results) Next, heat sealing was performed using the exterior materials of Examples 1-5 and Reference Examples 1 and 2 described above. The sealing layers of the two exterior materials were aligned, and a 10 mm wide section was heat-sealed under the conditions of 190°C, 3 seconds, and 1 MPa. After heat sealing, the exterior materials were left in a 23°C atmosphere for 24 hours.

[0100] The seal strength (N / 15mm) of the heat-sealed exterior material was measured. The seal strength was measured in an atmosphere of 23°C using a method compliant with the JIS-Z-1707 standard. This seal strength corresponds to the force required to peel the seal or tear the exterior material when a 15mm wide heat-sealed section is opened 180° and pulled. The experimental results of the seal strength for each example and reference example are shown in Table 1 below.

[0101] Furthermore, the remaining thickness of the exterior material after heat sealing was measured. The remaining thickness of the exterior material after heat sealing was calculated using the formula: "(thickness of the exterior material in the heat-sealed portion) / (thickness of the exterior material before heat sealing) × 100". Here, the thickness of the exterior material was measured by cutting a cross-section of the exterior material and using measurement software with a microscope. The experimental results of the remaining thickness of the exterior material after heat sealing for each example and reference example are shown in Table 1 below.

[0102] A larger remaining thickness of the exterior material after heat sealing indicates smaller thermal displacement during heat sealing. Conversely, a smaller remaining thickness of the exterior material after heat sealing indicates larger thermal displacement during heat sealing. Note that if the remaining thickness of the exterior material after heat sealing is too small, the thermal displacement will be too large, increasing the likelihood of a short circuit between the barrier layer in the exterior material and the electrode material.

[0103] Furthermore, for each example and reference example, the degree of needle penetration (needle penetration depth) was measured while increasing the temperature of the outer material (outer material before heat sealing). The needle penetration depth was measured in a nitrogen atmosphere and under a pressure of 500 mN, while increasing the temperature from 80°C to 200°C at a heating rate of 5°C / min, by pressing a needle with a tip diameter of 0.5 mm against the outer material from the seal layer side, in accordance with the JIS-K-7196 standard. The experimental results of the needle penetration depth for each example and reference example are shown in Table 1 below. The needle penetration depth (%) listed in Table 1 is defined by the value expressed as a percentage (%), obtained by dividing the needle penetration depth at a temperature of 200°C by the thickness of the outer material before measurement, and multiplying the result by 100.

[0104] A greater needle penetration depth indicates greater thermal displacement of the outer casing material. Therefore, if the needle penetration depth is too great, the possibility of a short circuit between the barrier layer in the outer casing material and the electrode material increases during heat sealing. Conversely, if the needle penetration depth is too small, it becomes difficult to heat seal the outer casing material. For this reason, it is preferable that the needle penetration depth be within a moderate range, neither too large nor too small.

[0105] (Table 1) TIFF2026144231000002.tif255163

[0106] Referring to Table 1, it can be seen that, compared to the exterior material of Reference Example 1, the exterior materials of Examples 1 to 5 achieve both high sealing strength and suppression of thermal displacement during heat sealing. Therefore, the exterior materials of Examples 1 to 5 can suppress thermal displacement during heat sealing while maintaining sealing strength.

[0107] Furthermore, in Reference Example 2, the heat resistance of the exterior material is low, and the thermal displacement of the exterior material is too large. In other words, in Reference Example 2, the thickness of the exterior material after heat sealing becomes too small, and the needle penetration depth is too large. In this case, for example, there is a possibility that the metal material constituting the barrier layer may short-circuit electrically. In contrast, in the exterior materials of Examples 1 to 5, compared to Reference Example 2, the thickness of the exterior material after heat sealing is large, and the needle penetration depth is small. Therefore, in the exterior materials of Examples 1 to 5, thermal displacement during heat sealing is suppressed.

[0108] In the exterior materials according to Examples 1 and 2, the thickness of the exterior material after heat sealing is greater and the needle penetration depth is smaller compared to Example 5. Furthermore, the seal strength (seal N / 15mm) of the exterior materials according to Examples 1 and 2 is greater than that of the exterior material according to Example 5. Therefore, the exterior materials according to Examples 1 and 2, i.e., the exterior materials according to the first and second embodiments, are more preferable than the exterior material according to Example 5, i.e., the exterior material according to the third embodiment.

[0109] The sealing strength of the exterior material according to Example 1 is higher than that of the exterior material according to Example 3. This is thought to be because the density of the polyethylene resin in the first intermediate layer 42 of the electron beam crosslinked layer 40 and the density of the polyethylene resin in the second intermediate layer 52 of the sealing layer 50 in Example 1 are greater than the density of the polyethylene resin in the inner surface layer 52 of the sealing layer 50.

[0110] Therefore, it is more preferable that the density of the polyethylene resin in the first intermediate layer 42 of the electron beam crosslinked layer 40, and / or the density of the polyethylene resin in the second intermediate layer 52 of the seal layer 50, is greater than the density of the polyethylene resin in the inner surface layer 52 of the seal layer 50.

[0111] It should be noted that, as explained above, at least the following inventions are explicitly stated in this specification.

[0112] [Note 1] Barrier layer, The electron beam crosslinking layer on the barrier layer, The electron beam crosslinking layer comprises a sealing layer, The electron beam crosslinked layer comprises at least one layer of electron beam crosslinked polyethylene resin. The sealing layer comprises at least one layer of non-electron-beam crosslinked polyethylene resin, and is an exterior material for a battery.

[0113] [Note 2] The sealing layer comprises at least two layers of non-electron-beam crosslinked polyethylene resin, as described in Appendix 1, for the battery casing material.

[0114] [Note 3] The sealing layer comprises an inner surface layer containing an electron beam crosslinked polyethylene resin, It has a second intermediate layer located between the inner surface layer and the electron beam crosslinked layer, and containing an electron beam crosslinked polyethylene resin, The battery exterior material according to Appendix 1 or 2, wherein the density of the polyethylene resin contained in the second intermediate layer is equal to or greater than the density of the polyethylene resin contained in the inner surface layer.

[0115] [Note 4] The battery exterior material according to Appendix 3, wherein the density of the polyethylene resin contained in the second intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

[0116] [Note 5] The outer casing material for a battery as described in any one of the appendices 1 to 4, wherein the thickness of the sealing layer is in the range of 6 μm to 20 μm.

[0117] [Note 6] The outer casing material for a battery according to any one of the appendices 1 to 5, wherein the thickness of the electron beam crosslinking layer is in the range of 6 μm to 20 μm.

[0118] [Note 7] The electron beam crosslinked layer comprises at least two layers of electron beam crosslinked polyethylene resin, as described in any one of the appendices 1 to 6, for the battery casing material.

[0119] [Note 8] The electron beam crosslinking layer is An adhesive layer bonded to the barrier layer or the chemical conversion treatment layer on the barrier layer, A first intermediate layer located between the adhesive layer and the sealing layer, It has, The first intermediate layer comprises at least one layer of electron-beam crosslinked polyethylene resin, the battery casing material according to any one of the appendices 1 to 7.

[0120] [Note 9] The battery casing material according to Appendix 8, wherein the density of the polyethylene resin constituting the first intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

[0121] [Note 10] The electron beam crosslinked layer is bonded to the barrier layer or the chemical treatment layer on the barrier layer and has an adhesive layer containing an electron beam crosslinked polyethylene resin, the battery exterior material according to any one of the appendices 1 to 9.

[0122] [Note 11] The adhesive layer comprises an electron beam crosslinked acid-modified polyethylene resin, as described in any one of the appendices 8 to 10, for use as an exterior material for a battery.

[0123] [Note 12] The outer casing material for a battery according to any one of the appendices 1 to 11, wherein the gel fraction of the polyethylene resin constituting the electron beam crosslinked layer is in the range of 10% to 80%.

[0124] [Note 13] Battery casing material as described in any one of the appendices 1 to 12, A battery comprising an electrode material encased in the aforementioned outer material.

[0125] [Note 14] A method for manufacturing an outer casing material for a battery as described in any one of the appendices 1 to 12, The steps include: irradiating at least one layer of polyethylene resin laminated on a barrier layer with an electron beam to form an electron beam crosslinked layer; A method for manufacturing an exterior material for a battery, comprising the step of laminating at least one layer of non-electron-beam crosslinked polyethylene resin on the electron beam crosslinked layer to form a sealing layer.

[0126] [Note 15] The method for manufacturing an exterior material for a battery according to Appendix 14, wherein the sealing layer comprises at least two layers of non-electron beam crosslinked polyethylene resin.

[0127] [Note 16] The sealing layer comprises an inner surface layer containing an electron beam crosslinked polyethylene resin, It has a second intermediate layer located between the inner surface layer and the electron beam crosslinked layer, and containing an electron beam crosslinked polyethylene resin, A method for manufacturing an exterior material for a battery according to Appendix 14 or 15, wherein the density of the polyethylene resin contained in the second intermediate layer is equal to or greater than the density of the polyethylene resin contained in the inner surface layer.

[0128] [Note 17] The method for manufacturing an exterior material for a battery according to Appendix 16, wherein the density of the polyethylene resin contained in the second intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

[0129] [Note 18] A method for manufacturing an exterior material for a battery according to any one of appendices 14 to 17, wherein the thickness of the sealing layer is in the range of 6 μm to 20 μm.

[0130] [Note 19] A method for manufacturing an exterior material for a battery according to any one of the appendices 14 to 18, wherein the thickness of the electron beam crosslinked layer is in the range of 6 μm to 20 μm.

[0131] [Note 20] A method for manufacturing an exterior material for a battery according to any one of appendices 14 to 19, wherein the electron beam crosslinked layer comprises at least two layers of electron beam crosslinked polyethylene resin.

[0132] [Note 21] The electron beam crosslinking layer is Adhesive layer and A first intermediate layer located between the adhesive layer and the sealing layer, It has, The first intermediate layer comprises at least one layer of electron-beam crosslinked polyethylene resin. The method for manufacturing an exterior material for a battery according to any one of appendices 14 to 20, further comprising the step of bonding the electron beam crosslinking layer to the barrier layer via the adhesive layer.

[0133] [Note 22] The method for manufacturing an exterior material for a battery according to Appendix 21, wherein the density of the polyethylene resin constituting the first intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

[0134] [Note 23] The electron beam crosslinked layer has an adhesive layer containing an electron beam crosslinked polyethylene resin, The method for manufacturing an exterior material for a battery according to any one of appendices 14 to 22, further comprising the step of bonding the electron beam crosslinking layer to the barrier layer via the adhesive layer.

[0135] [Note 24] The method for manufacturing an exterior material for a battery according to any one of the appendices 21 to 23, wherein the adhesive layer comprises an electron beam crosslinked acid-modified polyethylene resin.

[0136] As described above, the content of the present invention has been disclosed through embodiments and examples, but the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. Therefore, the technical scope of the present invention is defined solely by the inventive features relating to the claims that are reasonable from the above description. [Explanation of symbols]

[0137] 10 Exterior materials 30 Barrier layer 40 Electron beam crosslinked layer 42. First Meso-Place 44 Adhesive layer 50 sealing layers 52. Second Meso-Marginal Layer 54 Inner surface layer

Claims

1. Barrier layer, The electron beam crosslinking layer on the barrier layer, The electron beam crosslinking layer comprises a sealing layer, The electron beam crosslinked layer comprises at least one layer of electron beam crosslinked polyethylene resin. The sealing layer comprises at least one layer of non-electron-beam crosslinked polyethylene resin, and is an exterior material for a battery.

2. The sealing layer comprises at least two layers of electron beam crosslinked polyethylene resin, as described in claim 1, for the battery exterior material.

3. The sealing layer comprises an inner surface layer containing an electron beam crosslinked polyethylene resin, It has a second intermediate layer located between the inner surface layer and the electron beam crosslinked layer, and containing an electron beam crosslinked polyethylene resin, The battery exterior material according to claim 1, wherein the density of the polyethylene resin contained in the second intermediate layer is equal to or greater than the density of the polyethylene resin contained in the inner surface layer.

4. The battery exterior material according to claim 3, wherein the density of the polyethylene resin contained in the second intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

5. The exterior material for a battery according to claim 1, wherein the thickness of the sealing layer is in the range of 6 μm to 20 μm.

6. The outer casing material for a battery according to claim 1, wherein the thickness of the electron beam crosslinking layer is in the range of 6 μm to 20 μm.

7. The exterior material for a battery according to claim 1, wherein the electron beam crosslinked layer comprises at least two layers of electron beam crosslinked polyethylene resin.

8. The aforementioned electron beam crosslinking layer is An adhesive layer bonded to the barrier layer or the chemical conversion treatment layer on the barrier layer, A first intermediate layer located between the adhesive layer and the sealing layer, It has, The battery casing material according to claim 1, wherein the first intermediate layer comprises at least one layer of electron beam crosslinked polyethylene resin.

9. The battery exterior material according to claim 8, wherein the density of the polyethylene resin constituting the first intermediate layer is greater than the density of the polyethylene resin contained in the inner surface layer.

10. The exterior material for a battery according to claim 1, wherein the electron beam crosslinked layer is bonded to the barrier layer or the chemical treatment layer on the barrier layer and has an adhesive layer containing an electron beam crosslinked polyethylene resin.

11. The exterior material for a battery according to claim 8, wherein the adhesive layer comprises an electron beam crosslinked acid-modified polyethylene resin.

12. The battery exterior material according to claim 1, wherein the gel fraction of the polyethylene resin constituting the electron beam crosslinked layer is in the range of 10% to 80%.

13. An exterior material for a battery according to any one of claims 1 to 12, A battery comprising an electrode material encased in the aforementioned outer material.

14. A method for manufacturing an exterior material for a battery according to any one of claims 1 to 12, The steps include: irradiating at least one layer of polyethylene resin laminated on a barrier layer with an electron beam to form an electron beam crosslinked layer; A method for manufacturing an exterior material for a battery, comprising the step of laminating at least one layer of non-electron-beam crosslinked polyethylene resin on the electron beam crosslinked layer to form a sealing layer.

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