Core member, core, energy storage element with core, and energy storage device

Abstract

A core member to be disposed on a winding shaft of an electricity storage element of an electricity storage device, which can increase the production efficiency of the electricity storage device, is provided. A core member disposed on a winding shaft portion of an electricity storage element of an electricity storage device, The surface of the winding core member on the side of the electric storage element is formed of a metal adhesive resin layer.

Description

[Technical Field]

[0001] The present disclosure relates to a core member, a core, an electricity storage element with a core, and an electricity storage device. [Background technology]

[0002] An example of an electric storage element used in an electric storage device is one that includes a strip-shaped positive electrode plate, a strip-shaped separator, and a strip-shaped negative electrode plate, and is wound around a winding core. A winding core may be provided on the winding shaft portion of the electric storage element. The winding core provided on the winding shaft portion of the electric storage element supports the electrode plates on the inner periphery of the electric storage element, thereby suppressing bending of the inner periphery of the electric storage element and, for example, reducing variation in electric storage characteristics.

[0003] An electricity storage element having a winding core provided on a winding shaft is obtained by placing the winding core on the rotating shaft of a winding device, arranging electrode plates and separators around the winding core, and then rotating the rotating shaft to wind the electrode plates and separators around the winding core, and removing the wound electrode plates and separators with the winding core attached from the rotating shaft. The electricity storage element and electrolyte obtained in this manner are housed in a housing portion of an exterior material that corresponds to the shape of the electricity storage element, and the opening of the housing portion is sealed to obtain an electricity storage device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-74289 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, the winding core of an electricity storage device is formed by rolling a sheet-like winding core member into a cylindrical shape and securing the ends with tape. Furthermore, a method for securing the winding core and the electricity storage element is employed in which the electricity storage element is secured to the outer peripheral surface of the winding core with tape and then wound around the winding core so as to cover the entire outer peripheral surface (see Patent Document 1). However, a new problem has been discovered with methods that use tape for fastening: low production efficiency of electricity storage devices. Furthermore, methods that use tape for fastening have problems such as reduced electrical capacity and a shorter lifespan, because the thickness of the tape reduces the filling rate of the contents, such as the electricity storage element and electrolyte, compared to fastening methods that do not use tape.

[0006] A primary object of the present disclosure is to provide a core member to be disposed on a winding shaft of an electricity storage element of an electricity storage device, which can improve the production efficiency of the electricity storage device. Another object of the present disclosure is to provide a core, an electricity storage element with a core, and an electricity storage device that use the core member. [Means for solving the problem]

[0007] The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. As a result, they found that by forming the surface of the winding core member facing the storage element with a metal adhesive resin layer, it is not necessary to use tape to fix the winding core and the storage element, and the production efficiency of the storage element can be improved. The present disclosure was completed through further research based on this finding.

[0008] That is, the present disclosure provides the inventions of the following aspects. A core member disposed on a winding shaft portion of an electricity storage element of an electricity storage device, The surface of the winding core member on the side of the electric storage element is formed of a metal adhesive resin layer. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a core member to be disposed on a winding shaft of an electricity storage element of an electricity storage device, which can improve the production efficiency of the electricity storage device. Another object of the present disclosure is to provide a core, an electricity storage element with a core, and an electricity storage device using the core member. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a schematic plan view of a core member according to the present disclosure. [Figure 2] FIG. 2 is a schematic plan view of a core member according to the present disclosure. [Figure 3] FIG. 2 is a schematic plan view of a core member according to the present disclosure. [Figure 4] FIG. 2 is a schematic plan view of a core member according to the present disclosure. [Figure 5] FIG. 2 is a schematic plan view of a core member according to the present disclosure. [Figure 6] FIG. 2 is a schematic diagram of an example of a winding core according to the present disclosure. [Figure 7] FIG. 2 is a schematic diagram of an example of a winding core according to the present disclosure. [Figure 8] FIG. 4 is a schematic diagram illustrating a method for measuring the rigidity of a core member. DETAILED DESCRIPTION OF THE INVENTION

[0011] The core member of the present disclosure is a core member disposed on a winding shaft portion of an electricity storage element of an electricity storage device, and the surface of the core member facing the electricity storage element is formed of a metal adhesive resin layer. Because the core member of the present disclosure has such characteristics, it can improve the production efficiency of electricity storage devices. More specifically, because the surface of the core member facing the electricity storage element is formed of a metal adhesive resin layer, it is not necessary to use tape to fix the winding core using the core member to the electricity storage element, and this can improve the production efficiency of electricity storage devices.

[0012] Hereinafter, the core member of the present disclosure, and the core, the electricity storage element with the core, and the electricity storage device that use the core member will be described in detail with reference to FIGS.

[0013] In this specification, when referring to a numerical range, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation "2 to 15 mm" means 2 mm or greater and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0014] Another method for confirming the MD of a core member is to observe the cross section of the core member (e.g., the cross section of the metal adhesive resin layer) using an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section where the average diameter of the island shapes in the direction perpendicular to the thickness direction of the core member is the largest can be determined as the MD. Specifically, the cross section in the length direction of the core member and each cross section at an angle of 10 degrees from the direction parallel to the cross section in the length direction up to the direction perpendicular to the cross section in the length direction (a total of 10 cross sections) are observed using an electron microscope to confirm the sea-island structure. Next, the shape of each individual island is observed in each cross section. For each island shape, the linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the core member to the rightmost end in the perpendicular direction is defined as the diameter y. For each cross section, the average of the diameters y of the top 20 island shapes in descending order of diameter y is calculated. The direction parallel to the cross section where the average diameter y of the island shapes is the largest is determined as the MD. Alternatively, for example, the core member can be left in an environment of 150° C. for 2 minutes, and the thermal shrinkage rate measured, and the larger shrinkage rate can be determined as MD.

[0015] 1. Core materials The winding core member of the present disclosure is a winding core member arranged on a winding shaft portion of an electric storage element of an electric storage device. The electric storage element includes a strip-shaped positive electrode plate, a strip-shaped separator, and a strip-shaped negative electrode plate, and is wound around a winding core so that a cross section perpendicular to the winding shaft is formed into a circular or oval shape. A winding core using the winding core member of the present disclosure is arranged on the winding shaft portion of the wound electric storage element. In the electric storage device, the positive electrode plate and the negative electrode plate are electrically connected to a positive electrode terminal and a negative electrode terminal, respectively. In the electric storage device, the electric storage element, wound around the winding core, is housed inside an exterior material together with an electrolyte and sealed by the exterior material.

[0016] The surface of the winding core member of the present disclosure facing the storage element is composed of a metal adhesive resin layer. This allows the metal adhesive resin layer of the winding core member and the storage element to be directly fixed by bonding such as heat fusion without using a fixing member such as tape. The fixation of the metal adhesive resin layer of the winding core member and the storage element is, for example, fixation of the metal adhesive resin layer of the winding core member and the positive electrode plate and / or the negative electrode plate of the storage element.

[0017] The metal adhesive resin layer of the core member can be fixed to the electricity storage element by, for example, heat-sealing the metal adhesive resin layer of the core member to the electricity storage element. In this case, the metal adhesive resin layer has heat-sealing properties to metal. Specifically, heat-sealing to metal means that the metal adhesive resin layer adheres to the surface of the metal (e.g., aluminum alloy foil) under conditions of a temperature of about 170 to 210°C, a surface pressure of about 0.5 to 2.0 MPa, and a time of about 1 to 5 seconds. In this case, adhesion means that the peel strength between the metal adhesive resin layer and the metal (e.g., aluminum alloy foil) is 5.0 N / 15 mm or more.

[0018] The winding core member 10 of the present disclosure may be composed of only a metal adhesive resin layer 1, as shown in Fig. 1, for example. Alternatively, the winding core member 10 of the present disclosure may include a base layer 2 in addition to the metal adhesive resin layer 1, as shown in Figs. 2 to 5, for example. In this case, the winding core member 10 of the present disclosure is composed of a laminate including at least the metal adhesive resin layer 1 and the base layer 2. When the winding core member 10 of the present disclosure is used as a winding core, the metal adhesive resin layer 1 faces the electricity storage element.

[0019] As shown in Figures 2 to 5, the base material layer 2 is preferably composed of at least one of a resin layer 21 and a metal layer 22. When the base material layer 2 has two or more layers, these layers may be bonded together with an adhesive layer 23. Figure 2 illustrates an embodiment in which the base material layer 2 is formed from a resin layer 21, Figure 3 illustrates an embodiment in which the base material layer 2 is formed from a metal layer 22, and Figure 4 illustrates an embodiment in which the base material layer 2 is formed from a laminate of the resin layer 21, the adhesive layer 23, and the metal layer 22. The winding core member 10 preferably has a configuration of 1 to 5 layers.

[0020] The core member 10 of the present disclosure may also include an adhesive layer 23 between the metal adhesive resin layer 1 and the substrate layer 2, for the purpose of increasing the adhesion between these layers.

[0021] As will be described later, when the winding core member 10 of the present disclosure is used for the winding core 11, the winding core member 10 of the present disclosure may or may not be formed into a cylindrical shape. FIGS. 6 and 7 illustrate how the ends of the winding core member 10 formed into a cylindrical shape overlap and are fixed by, for example, heat fusion of the metal adhesive resin layer 1. When the winding core member 10 of the present disclosure is formed into a cylindrical shape, the ends of the winding core member 10 formed into a cylindrical shape may or may not overlap. Furthermore, the ends of the winding core member 10 formed into a cylindrical shape may or may not be fixed to each other. When the ends of the winding core member 10 formed into a cylindrical shape are fixed to each other, the ends may be fixed by, for example, heat fusion of the metal adhesive resin layer 1, or the ends may be fixed using a fixing member such as tape. Methods for fixing the ends by heat fusion include a method in which the metal adhesive resin layers 1 of cylindrically formed winding core members 10 are overlapped so that the inner surfaces or outer surfaces face each other, and then heat-sealed to heat-fuse, or a method in which the ends are overlapped so that the outer and inner surfaces of cylindrically formed winding core members 10 overlap, and the overlapped portion is heat-sealed. If the ends of the cylindrically formed winding core member 10 are not fixed to each other, the winding core 11 moves in response to the expansion and contraction of the electricity storage element when the electricity storage device is charged and discharged, which has the effect of suppressing an increase in the internal pressure of the electricity storage device.

[0022] The thickness of the core member 10 is not particularly limited, but from the viewpoint of exhibiting functions such as rigidity and dead hold as a core member, it is preferably about 50 μm or more, more preferably about 100 μm or more, and even more preferably about 200 μm or more. From the viewpoint of increasing the filling rate of contents such as the storage element and electrolyte and reducing costs, it is preferably about 350 μm or less, more preferably about 300 μm or less, and even more preferably about 250 μm or less, and preferred ranges include about 50 to 350 μm, about 50 to 300 μm, about 50 to 250 μm, about 100 to 350 μm, about 100 to 300 μm, and about 100 to 250 μm.

[0023] In the winding core member 10, the ratio of the total thickness of the metal adhesive resin layer 1 and the base material layer 2, which is provided as needed, to the thickness (total thickness) of the layers constituting the winding core member 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the winding core member 10 of the present disclosure includes the metal adhesive resin layer 1 and the base material layer 2, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the winding core member 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0024] When the winding core member 10 of the present disclosure is wound around a periphery, the winding member is deformed in a direction perpendicular to the winding axis due to an external force applied to the winding member, and from the viewpoint of suitably suppressing deflection and deformation of the electricity storage element, the rigidity measured under the following measurement conditions is preferably about 0.4 N / 15 mm or more, more preferably about 4.4 N / 15 mm or more, even more preferably about 7.0 N / 15 mm or more, and is preferably about 100 N / 15 mm or less, and more preferably about It is preferably about 60N / 15mm or less, and more preferably about 50N / 15mm or less, and preferred ranges include about 0.4 to 100N / 15mm, about 0.4 to 60N / 15mm, about 0.4 to 50N / 15mm, about 4.4 to 100N / 15mm, about 4.4 to 60N / 15mm, about 4.4 to 50N / 15mm, about 7.0 to 100N / 15mm, about 7.0 to 60N / 15mm, and about 7.0 to 50N / 15mm.

[0025] (Rigidity measurement conditions) Measuring equipment: Universal testing equipment (autograph) Measurement sample size: MD 100mm, TD 15mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: As shown in the schematic diagram of Figure 8, both ends in the MD direction of the measurement sample (winding core member 10) are attached to the lower chuck 32 of the universal testing machine, and the measurement sample is set in a loop shape. The upper chuck 31 of the universal testing machine is lowered at a constant speed of 50 m / min. The load (N / 15 mm) at the point when the upper chuck 31 has pressed the loop-shaped measurement sample 25 mm is taken as the rigidity value.

[0026] Furthermore, in order to suitably suppress the bending of the storage element wound around the core member 10 of the present disclosure, the angle of the bent portion measured under the following measurement conditions is preferably about 90° or less, more preferably about 45° or less, and preferred ranges include about 0 to 90° and about 0 to 45°.

[0027] (Conditions for measuring the angle of the bent part) Measuring device: glass plate and roller with a mass of 2 kg Measurement sample size: MD 200mm, TD 100mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: The measurement sample is folded in half in the MD direction so that the metal adhesive resin layers face each other. A roller with a mass of 2 kg is placed on the folded portion and the roller is moved back and forth five times in the TD direction. The measurement sample is placed on the glass plate so that the surface of the metal adhesive resin layer of the measurement sample is perpendicular to the surface of the glass plate, and allowed to stand for 1 minute. The angle of the folded portion of the measurement sample on the glass plate side is measured.

[0028] [Metal adhesive resin layer 1] In the core member 10 of the present disclosure, the metal adhesive resin layer 1 is a layer that constitutes the surface 10a on the electricity storage element side, and is formed from a resin that has adhesive properties to metal.

[0029] The type of resin forming the metal adhesive resin layer 1 is not particularly limited as long as it is a resin that exhibits adhesion to metals (more specifically, metals that constitute the positive electrode plate, negative electrode plate, etc. of the electricity storage element). Examples of resins contained in the metal adhesive resin layer 1 include modified polyolefins and polyesters. The resin contained in the metal adhesive resin layer 1 may be one type only, or two or more types.

[0030] Examples of modified polyolefins include acid-modified polyolefins and chlorinated polyolefins. These modified polyolefins have heat-fusible properties for metals. Acid-modified polyolefins are polymers modified by block polymerization or graft polymerization of polyolefins with an acid component.

[0031] The polyolefin to be modified may be any of the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, or polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0032] Specific examples of the polyolefin to be modified include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (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. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0033] The polyolefin to be modified may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0034] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0035] Furthermore, when the resin constituting the metal adhesive resin layer 1 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around . When the metal adhesive resin layer is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0036] The metal adhesive resin layer 1 preferably contains a resin containing a modified polyolefin skeleton as a main component, more preferably a modified polyolefin as a main component, and even more preferably a modified polypropylene as a main component. Here, "main component" refers to a resin component whose content is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably 99% by weight or more of the resin components contained in the metal adhesive resin layer 1. For example, "the metal adhesive resin layer 1 contains modified polypropylene as a main component" refers to a resin component whose content is, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, even more preferably 80% by weight or more, even more preferably 90% by weight or more, even more preferably 95% by weight or more, even more preferably 98% by weight or more, and even more preferably 99% by weight or more of the resin components contained in the metal adhesive resin layer 1.

[0037] In the metal adhesive resin layer 1, the polyester is preferably a modified polyester having an aromatic acid, an aliphatic acid, or a functional group as the acid component.

[0038] The thickness of the metal adhesive resin layer 1 is not particularly limited as long as it is thick enough to adhere to the storage element, but taking into consideration the adhesion when heat-welded to the electrode, it is preferably about 80 μm or less, more preferably about 50 μm or less, and even more preferably about 30 μm or less, and is also preferably 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and preferred ranges include about 10 to 80 μm, about 10 to 50 μm, about 10 to 30 μm, about 15 to 80 μm, about 15 to 50 μm, about 15 to 30 μm, about 20 to 80 μm, about 20 to 50 μm, and about 20 to 30 μm.

[0039] [Base material layer 2] The base material layer 2 is a layer that is provided as needed in the core member 10 for the purpose of functioning as a support for the metal adhesive resin layer 1, etc.

[0040] The substrate layer 2 preferably contains at least one of metal and resin. In the substrate layer 2, a layer formed of resin constitutes the resin layer 21. In addition, in the substrate layer 2, a layer formed of metal constitutes the metal layer 22. The inclusion of the metal layer 22 is preferable in terms of rigidity and dead hold ability of the substrate layer 2. When the substrate layer 2 is composed of two or more layers, the layers may be bonded together with an adhesive layer 23. In addition, the substrate layer 2 and the metal-adhesive resin layer 1 may be bonded together with an adhesive layer 23.

[0041] (Resin layer 21) There are no particular limitations on the material for forming the resin layer 21. The resin layer 21 can be formed using, for example, a resin, which may contain an additive described below. A plurality of resin layers 21 may be provided.

[0042] The resin layer 21 can be formed, for example, from a resin film. When the resin layer 21 is formed from a resin film, for example, when the base layer 2 is manufactured by laminating the resin layer 21 with the metal layer 22 or the like, a pre-formed resin film may be used as the resin layer 21. Alternatively, the resin forming the resin layer 21 may be formed into a film on the surface of the metal layer 22 or the like by extrusion molding, coating, or the like, to form the resin layer 21. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating. Stretched films generally have stronger stiffness because the molecules become denser when stretched, making them preferable from the viewpoint of rigidity.

[0043] Examples of resins that form the resin layer 21 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin that forms the resin layer 21 may also be a copolymer of these resins, a modified version of the copolymer, or a mixture of these resins.

[0044] The resin layer 21 preferably contains these resins as a main component, and more preferably contains polyester or polyolefin as a main component. Here, "main component" means that the resin component contained in the resin layer 21 has a content of, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the resin layer 21 contains polyester or polyolefin as a main component" means that the resin component contained in the resin layer 21 has a content of polyester or polyolefin of, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0045] Of these, polyester and polyolefin are preferred as the resin for forming the resin layer 21 from the viewpoints of cost and mechanical properties.

[0046] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Copolymer polyesters include copolymer polyesters whose repeating units are primarily ethylene terephthalate. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). Furthermore, the polyester may be a copolymer of two or more polyesters selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polyethylene isophthalate. These polyesters may be used alone or in the form of a mixture of two or more.

[0047] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (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. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0048] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, preferred are cyclic alkenes, and more preferred are norbornene.

[0049] The resin layer 21 preferably includes at least one of a polyester film and a polyolefin film, preferably includes at least one of a stretched polyester film and an unstretched polyolefin film, more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, and an unstretched polypropylene film, and even more preferably includes at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, and an unstretched polypropylene film.

[0050] The resin layer 21 may be a single layer, or may be composed of two or more layers. When the resin layer 21 is composed of two or more layers, the resin layer 21 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of two or more resin films formed by co-extrusion of resins. Furthermore, a laminate of two or more resin films formed by co-extrusion of resins may be used as the resin layer 21 without being stretched, or may be uniaxially or biaxially stretched to form the resin layer 21.

[0051] Specific examples of laminates of two or more resin films in resin layer 21 include laminates of polyester film and polyolefin film, laminates of two or more polyolefin films, and laminates of two or more polyester films. Preferred are laminates of stretched polyester film and unstretched polyolefin film, laminates of two or more stretched polyester films, and laminates of two or more polyolefin films. For example, when resin layer 21 is a laminate of two resin films, laminates of polyester resin film and polyester resin film, laminates of polyolefin resin film and polyolefin resin film, or laminates of polyester resin film and polyolefin resin film are preferred. More preferred are laminates of polyethylene terephthalate film and polyethylene terephthalate film, laminates of polypropylene film and polypropylene film, or laminates of polyethylene terephthalate film and polypropylene film. In laminates of polyester resin film and polyolefin resin film, the preferred thickness of the polyester resin film is about 50 to 100 μm, and the preferred thickness of the polyolefin resin film is about 20 to 100 μm.

[0052] When the resin layer 21 is a laminate of two or more resin film layers, the two or more resin film layers may be laminated via an adhesive. Examples of preferred adhesives include the same adhesives as those exemplified for the adhesive layer 23 described below. The method for laminating two or more resin film layers is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, with dry lamination being preferred. When laminating using the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive layer may be, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film before lamination. Examples of the anchor coat layer include the same adhesives as those exemplified for the adhesive layer 23 described below. In this case, the thickness of the anchor coat layer may be, for example, about 0.01 to 1.0 μm.

[0053] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and colorants may be present on at least one of the surface and the interior of the resin layer 21. Only one type of additive may be used, or two or more types may be mixed and used.

[0054] The thickness of the resin layer 21 is not particularly limited as long as it functions as a support, and is, for example, about 20 μm or more, preferably about 50 μm or more, more preferably about 80 μm or more, and is, for example, about 80 μm or less, preferably about 50 μm or less, more preferably about 20 μm or less, with a preferred range being around 20 to 80 μm.

[0055] (metal layer 22) There are no particular limitations on the material forming the metal layer 22. Examples of metals contained in the metal layer 22 include aluminum, copper, stainless steel, iron, steel, and magnesium. The metal layer 22 may be formed of only one type of metal, or two or more types of metals.

[0056] An example of the metal layer 22 is a metal foil. The metal layer 22 may be provided in a plurality of layers. The metal layer 22 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the metal layer 22 include aluminum alloy, stainless steel, titanium steel, and steel plate. When used as a metal foil, the metal layer 22 preferably includes at least one of an aluminum alloy foil and a stainless steel foil.

[0057] In the metal layer 22, layers made of the aforementioned metal materials may contain recycled metal materials. Examples of recycled metal materials include recycled aluminum alloys, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloys can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The metal layer 22 may be made solely of recycled materials, or may be made of a mixture of recycled and virgin materials. Note that recycled metal materials refer to metal materials that have been made reusable by recovering, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.

[0058] The aluminum alloy foil is not particularly limited, but from the viewpoint of rigidity, a hard foil is preferable. Alternatively, a soft foil obtained by subjecting a hard foil to thermal annealing or the like can also be used. For example, a soft aluminum alloy foil made of an annealed aluminum alloy is preferably an iron-containing aluminum alloy foil. In an iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. Examples of soft aluminum alloy foils include aluminum alloy foils having compositions specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may also be added as necessary. Softening can be achieved by annealing or the like.

[0059] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. The stainless steel foil is preferably made of austenitic stainless steel.

[0060] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0061] The thickness of the metal layer 22 is preferably about 200 μm or less, more preferably about 150 μm or less, and even more preferably about 120 μm or less from the viewpoint of deadhold properties, and is preferably about 60 μm or more, more preferably about 80 μm or more, and even more preferably about 100 μm or more from the viewpoint of rigidity, and preferred ranges include about 60 to 200 μm, about 60 to 150 μm, about 60 to 120 μm, about 80 to 200 μm, about 80 to 150 μm, about 80 to 120 μm, about 100 to 200 μm, about 100 to 150 μm, and about 100 to 120 μm.

[0062] Furthermore, when the metal layer 22 is a metal foil, a corrosion-resistant coating may be provided on at least the surface opposite the substrate layer to prevent dissolution and corrosion. The metal layer 22 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the surface of the metal layer, for example, by hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the metal layer (acid-resistant coating), a coating that improves the alkali resistance of the metal layer (alkali-resistant coating), etc. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, not only one layer but also multiple layers can be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments that dissolve the metal foil surface with a treatment agent to form a metal compound with excellent corrosion resistance. These treatments may be included in the definition of chemical conversion treatment. In addition, when the metal layer 22 is provided with a corrosion-resistant coating, the metal layer 22 includes the corrosion-resistant coating.

[0063] The corrosion-resistant coating prevents delamination between a metal layer (e.g., aluminum alloy foil) and an adjacent layer, prevents dissolution and corrosion of the metal layer surface due to hydrogen fluoride produced by a reaction between an electrolyte and water, and in particular prevents dissolution and corrosion of aluminum oxide present on the metal layer surface when the metal layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the metal layer surface, thereby exhibiting the effect of improving adhesion.

[0064] Various corrosion-resistant coatings formed by chemical conversion treatments are known, including corrosion-resistant coatings containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromate chromate treatment, phosphate chromate treatment, phosphate-chromate treatment, and chromate treatment. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetylacetate, chromium chloride, and potassium chromium sulfate. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, and paint-on chromate treatment, with paint-on chromate treatment being preferred. This paint-type chromate treatment involves first degreasing at least the inner surface of a metal layer (e.g., aluminum alloy foil) using a well-known method such as alkaline immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then coating the degreased surface with a treatment solution primarily composed of a metal phosphate (e.g., chromium phosphate, titanium phosphate, zirconium phosphate, zinc phosphate, or a mixture of these metal salts), a treatment solution primarily composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a treatment solution consisting of a mixture of these with a synthetic resin or the like, using a well-known coating method such as roll coating, gravure printing, or immersion, and then drying. The treatment solution can be, for example, water, alcoholic solvents, hydrocarbon solvents, ketone solvents, ester solvents, or ether solvents, with water being preferred. The resin component used here may be a polymer such as a phenolic resin or an acrylic resin, or may be a chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4): In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.The acrylic resin is preferably polyacrylic acid, an acrylic acid methacrylic acid ester copolymer, an acrylic acid maleic acid copolymer, an acrylic acid styrene copolymer, or a derivative thereof such as a sodium salt, an ammonium salt, or an amine salt. A derivative of polyacrylic acid, such as an ammonium salt, a sodium salt, or an amine salt of polyacrylic acid, is particularly preferred. In the present disclosure, polyacrylic acid refers to a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, or an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. 1 and R 2 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2Examples of the alkyl group represented by X and R include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) include a linear or branched alkyl group having 1 to 4 carbon atoms substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. 1 and R 2 The alkyl group and hydroxyalkyl group represented by the formula (1) may be the same or different. In the formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by the formulas (1) to (4) is preferably about 500 to 1,000,000, and more preferably about 1,000 to 20,000. The aminated phenol polymer can be prepared, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer comprising repeating units represented by the formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to the functional group (-CHNR 1 R 2 The aminated phenol polymers can be used singly or in combination of two or more.

[0070] Another example of a corrosion-resistant coating is a thin film formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. The coating agent may further contain phosphoric acid or a phosphate salt, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol has rare earth element oxide fine particles (e.g., particles with an average particle size of 100 nm or less) dispersed in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, with cerium oxide being preferred from the perspective of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant coating can be used alone or in combination of two or more. The liquid dispersion medium for the rare earth element oxide sol can be various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, with water being preferred. Preferred examples of cationic polymers include polyethyleneimine, ionic polymer complexes composed of polyethyleneimine and a polymer having a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic backbone, polyallylamine or its derivatives, and aminated phenols. Preferred anionic polymers are poly(meth)acrylic acid or its salts, or copolymers primarily composed of (meth)acrylic acid or its salts. The crosslinking agent is preferably at least one selected from the group consisting of a compound having a functional group selected from an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. The phosphoric acid or phosphoric acid salt is preferably a condensed phosphoric acid or a condensed phosphate salt.

[0071] An example of a corrosion-resistant coating is one formed by applying a solution of phosphoric acid in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate, are dispersed to the surface of a metal layer and then baking the coating at 150°C or higher.

[0072] The corrosion-resistant coating may have a laminated structure, if necessary, by further laminating at least one of a cationic polymer and an anionic polymer, such as those mentioned above.

[0073] The composition of the corrosion-resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

[0074] The amount of the corrosion-resistant film formed on the surface of the metal layer 22 in the chemical conversion treatment is not particularly limited. For example, in the case of applying chromate treatment, the amount of the corrosion-resistant film formed on the surface of the metal layer 22 is 2 It is desirable that the chromate compound is contained in an amount, in terms of chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound in terms of phosphorus, and the aminated phenol polymer in an amount, in terms of phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per unit area.

[0075] The thickness of the corrosion-resistant coating is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm, from the viewpoint of the cohesive strength of the coating and the adhesive strength with the metal layer and the heat-sealable resin layer. The thickness of the corrosion-resistant coating can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. Analysis of the composition of the corrosion-resistant coating using time-of-flight secondary ion mass spectrometry can reveal the thickness of the corrosion-resistant coating, for example, by measuring the thickness of the corrosion-resistant coating with secondary ions consisting of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - At least one of the following ions may be present: Cr, P, and O secondary ions (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0076] The chemical conversion treatment is carried out by applying a solution containing a compound used to form a corrosion-resistant coating to the surface of the metal layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the metal layer to a temperature of approximately 70 to 200°C. Furthermore, before applying the chemical conversion treatment to the metal layer, the metal layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or other methods. By performing such a degreasing treatment, the chemical conversion treatment of the surface of the metal layer can be carried out more efficiently. Furthermore, using an acid degreasing agent prepared by dissolving a fluorine-containing compound in an inorganic acid for the degreasing treatment not only degreases the metal foil but also forms a passive metal fluoride. In such cases, only the degreasing treatment may be performed.

[0077] (adhesive layer 23) The adhesive layer 23 is a layer that is provided between layers of the winding core member 10 as needed for the purposes of increasing the adhesiveness between layers included in the base material layer 2 and between the base material layer 2 and other layers (for example, the metal adhesive resin layer 1). When the winding core member 10 includes the adhesive layer 23, the adhesive layer 23 may be one layer or two or more layers.

[0078] The adhesive layer 23 can be suitably provided, for example, between the resin layer 21 and the metal layer 22 of the base material layer 2, between the resin layers 21 and 21 of the base material layer 2, between the metal layers 22 and 22 of the base material layer 2, or between the base material layer 2 and the metal-adhesive resin layer 1. In the present disclosure, since the metal-adhesive resin layer 1 has adhesive properties to metal, it is also preferable that no adhesive layer 23 is provided between the metal layer 22 and the metal-adhesive resin layer 1, and the metal layer 22 and the metal-adhesive resin layer 1 are directly bonded (thermally fused) to each other.

[0079] The adhesive used to form adhesive layer 23 is not limited, and may be any of a chemical reaction type, a solvent evaporation type, a hot melt type, a hot pressure type, etc. Also, it may be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Also, adhesive layer 23 may be a single layer or multiple layers.

[0080] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin-based resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination. Among these adhesive components, polyurethane adhesives are preferred. Furthermore, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected appropriately from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups of the adhesive components.

[0081] Examples of polyurethane adhesives include polyurethane adhesives containing a first part containing a polyol compound and a second part containing an isocyanate compound. Preferred examples include two-component curing polyurethane adhesives, with a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the first part and an aromatic or aliphatic polyisocyanate as the second part. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and an isocyanate compound. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives obtained by reacting a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance with moisture, such as in the air, and curing the polyurethane compound. Polyol compounds preferably include polyester polyols having hydroxyl groups on the side chains in addition to terminal hydroxyl groups in the repeating units. Examples of the second part include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Multimers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such multimers include adducts, biurets, and nurates. Forming the adhesive layer 23 from a polyurethane adhesive provides excellent electrolyte resistance.

[0082] The resin used to form the adhesive layer 23 preferably contains a polyolefin skeleton, and examples thereof include the polyolefins, acid-modified polyolefins, cyclic polyolefins, and acid-modified cyclic polyolefins exemplified for the metal-adhesive resin layer 1 or resin layer 21. From the viewpoint of enhancing adhesion to the metal layer, the adhesive layer 23 preferably contains an acid-modified polyolefin. Examples of acid-modified components include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, as well as their anhydrides, acrylic acid, and methacrylic acid. However, maleic anhydride is most preferred in terms of ease of modification and versatility. From the viewpoint of heat resistance, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 23 most preferably contains maleic anhydride-modified polypropylene.

[0083] When the resin used to form the adhesive layer 23 contains a polyolefin skeleton, the adhesive layer 23 preferably contains a resin containing a polyolefin skeleton as a primary component, more preferably an acid-modified polyolefin as a primary component, and even more preferably an acid-modified polypropylene as a primary component. Here, "primary component" refers to a resin component that accounts for, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more of the resin components contained in the adhesive layer 23. For example, "the adhesive layer 23 contains acid-modified polypropylene as a primary component" refers to a resin component that accounts for, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more of the acid-modified polypropylene among the resin components contained in the adhesive layer 23.

[0084] The presence of a polyolefin skeleton in the resin constituting the adhesive layer 23 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. Furthermore, the presence of an acid-modified polyolefin in the resin constituting the adhesive layer 23 can be determined by, for example, measuring a maleic anhydride-modified polyolefin by infrared spectroscopy, and finding a peak at a wave number of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0085] Furthermore, it is more preferable that the adhesive layer 23 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

[0086] The adhesive layer 23 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. The adhesive layer 23 is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 23 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. Examples of polyesters include ester resins formed by the reaction of epoxy groups with maleic anhydride groups, and amide ester resins formed by the reaction of oxazoline groups with maleic anhydride groups. If unreacted components of a curing agent, such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin, remain in the adhesive layer 23, the presence of the unreacted components can be confirmed by a method selected from the group consisting of infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

[0087] Furthermore, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 23, the adhesive layer 23 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C═N bond, and a COC bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C═N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a COC bond include curing agents having an oxazoline group and curing agents having an epoxy group. Whether the adhesive layer 23 is a cured product of a resin composition containing such a curing agent can be confirmed by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or other methods.

[0088] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the barrier layer 3 and the adhesive layer 23, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures of these, and copolymers with other polymers. Other examples include adducts, biurets, and isocyanurates.

[0089] The content of the compound having an isocyanate group in the adhesive layer 23 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition constituting the adhesive layer 23. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 23.

[0090] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0091] The proportion of the compound having an oxazoline group in the adhesive layer 23 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition constituting the adhesive layer 23. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 23.

[0092] An example of a compound having an epoxy group is an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably about 50 to 2,000, more preferably about 100 to 1,000, and even more preferably about 200 to 800. In the present disclosure, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0093] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0094] The proportion of the epoxy resin in the adhesive layer 23 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition constituting the adhesive layer 23. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 23.

[0095] The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 23 may be, for example, a cured product of two-component curing polyurethane.

[0096] The proportion of polyurethane in adhesive layer 23 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition constituting adhesive layer 23. This effectively improves the adhesion between barrier layer 3 and adhesive layer 23 in an atmosphere containing components that induce corrosion of the barrier layer, such as an electrolyte solution.

[0097] In addition, when the adhesive layer 23 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as the main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0098] The adhesive layer 23 may contain a modifier having a carbodiimide group.

[0099] The adhesive layer 23 may contain other components as long as they do not impair adhesion, such as colorants, thermoplastic elastomers, tackifiers, and fillers. The adhesive layer 23 may contain a colorant, thereby coloring the core member. Known colorants, such as pigments and dyes, can be used. Only one type of colorant may be used, or two or more types may be mixed together.

[0100] The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 23. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include finely powdered mica and fish scale foil.

[0101] Among colorants, carbon black is preferred in order to give the core member a black appearance, and mica is preferred in terms of dissipating heat generated by the electricity storage device.

[0102] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution measuring device.

[0103] The content of the colorant in the adhesive layer 23 is not particularly limited as long as it colors the core member, and may be, for example, about 5 to 60 mass %, and preferably 10 to 40 mass %.

[0104] The thickness of the adhesive layer 23 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. The thickness of the adhesive layer 23 is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness of the adhesive layer 23 is preferably in the range of about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm. More specifically, when the adhesive layer 23 is formed from a cured product of the polyurethane adhesive or a cured product of an acid-modified polyolefin and a curing agent, the thickness may be about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, or about 2 to 5 μm. Furthermore, when polyolefin, acid-modified polyolefin, cyclic polyolefin, acid-modified cyclic polyolefin, or the like exemplified for the metal adhesive resin layer 1 or the resin layer 21 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 23 is a cured product of a polyurethane adhesive or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 23 can be formed, for example, by applying a resin composition to be used as an adhesive and curing it by heating or the like. Furthermore, when polyolefin, acid-modified polyolefin, cyclic polyolefin, acid-modified cyclic polyolefin, or the like exemplified for the metal adhesive resin layer 1 or the resin layer 21 is used, the adhesive layer 23 can be formed, for example, by extrusion molding.

[0105] The method for manufacturing the winding core member of the present disclosure is not particularly limited as long as it produces a winding core member 10 whose surface 10a on the side of the electricity storage element is constituted by the metal adhesive resin layer 1. When the winding core member 10 of the present disclosure is constituted only by the metal adhesive resin layer 1, the metal adhesive resin film that forms the metal adhesive resin layer 1 can be the winding core member 10 of the present disclosure.

[0106] Furthermore, when the winding core member 10 of the present disclosure is composed of a laminate including a base material layer 2 and a metal adhesive resin layer 1, the winding core member 10 can be manufactured by a method including a step of laminating the base material layer 2 and the metal adhesive resin layer 1. The lamination method for each layer can be (1) extrusion lamination, (2) thermal lamination, (3) sandwich lamination, (4) dry lamination, or the like.

[0107] In order to strengthen the adhesiveness of the adhesive layer 23, the laminate constituting the core member may be subjected to a heat treatment.

[0108] Each layer constituting the core member may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, or ozone treatment, as required, to improve processability.

[0109] 2. Core The winding core 11 of the present disclosure utilizes the winding core member 10 of the present disclosure. That is, the winding core 11 of the present disclosure includes the winding core member 10 of the present disclosure. The surface 10a of the winding core 11 of the present disclosure facing the storage element is formed by the metal adhesive resin layer 1 of the winding core member 10. This allows the metal adhesive resin layer 1 of the winding core member 10 and the storage element to be directly fixed together without using a fixing member such as tape. The fixation of the metal adhesive resin layer 1 of the winding core member 10 and the storage element can be, for example, fixation of the metal adhesive resin layer 1 of the winding core member 10 and the positive electrode plate and / or negative electrode plate of the storage element.

[0110] The winding core 11 of the present disclosure may be obtained by molding the winding core member 10 of the present disclosure into a cylindrical shape, as shown in FIG. 6, for example. The winding core 11 shown in FIGS. 6 and 7 illustrates a state in which the ends of the cylindrically molded winding core members 10 overlap and are fixed by heat fusion of the metal adhesive resin layer 1 or the like. In the winding core 11 of the present disclosure, when the winding core member 10 is molded into a cylindrical shape, the ends of the cylindrically molded winding core member 10 may or may not overlap as shown in FIGS. 6 and 7. Furthermore, the ends of the cylindrically molded winding core member 10 may or may not be fixed to each other. When the ends of the cylindrically molded winding core member 10 are fixed to each other, the ends may be fixed by heat fusion of the metal adhesive resin layer 1 or the like, or the ends may be fixed using a fixing member such as tape.

[0111] Furthermore, the winding core 11 of the present disclosure does not necessarily have to be formed into a cylindrical shape like the winding core member 10 of the present disclosure.

[0112] The winding core 11 of the present disclosure may be composed of only the winding core member 10 of the present disclosure, or may further include other members different from the winding core member 10. Examples of other members include metal members. For example, as shown in FIG. 7, the winding core 11 of the present disclosure may have a structure in which the winding core member 10 of the present disclosure is disposed on the outer periphery of a cylindrical metal member 12.

[0113] Examples of the metal member include those containing at least one selected from the group consisting of aluminum, copper, stainless steel, iron, steel, and magnesium.

[0114] The thickness of the metal member is, for example, approximately 50 μm or more, preferably 60 μm or more, more preferably 80 μm or more, and even more preferably 100 μm or more, and is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 120 μm or less. Preferred ranges include about 50 to 200 μm, about 50 to 150 μm, about 50 to 120 μm, about 60 to 200 μm, about 60 to 150 μm, about 60 to 120 μm, about 80 to 200 μm, about 80 to 150 μm, about 80 to 120 μm, about 100 to 200 μm, about 100 to 150 μm, about 100 to 120 μm, and about 50 to 200 μm.

[0115] 3. Core-wound energy storage element The core-equipped electricity storage element of the present disclosure includes a core 11 of the present disclosure on a winding shaft portion of the electricity storage element. That is, the core-equipped electricity storage element of the present disclosure includes a core member 10 of the present disclosure on a winding shaft portion of the electricity storage element. The electricity storage element is formed by winding a strip-shaped positive electrode plate and a strip-shaped negative electrode plate with a separator interposed therebetween, and has an oval cross section. In the core-equipped electricity storage element of the present disclosure, a core using the core member of the present disclosure is disposed on the winding shaft portion of the wound electricity storage element. The core-equipped electricity storage element of the present disclosure is housed inside an exterior material together with an electrolyte, and is sealed by the exterior material to form an electricity storage device.

[0116] For example, a rotating shaft of a winding device is inserted into the hollow portion of the winding core 11 of the present disclosure, and a positive electrode plate, a negative electrode plate, and a separator are arranged around the outer periphery of the winding core 11 so that the separator is disposed between the positive electrode plate and the negative electrode plate. When arranging the positive electrode plate, the negative electrode plate, and the separator, any of the positive electrode plate, the negative electrode plate, and the separator may be in contact with the surface of the winding core 11 (i.e., the surface 10a of the metal-adhesive resin layer 1 of the winding core member 10). However, since the metal-adhesive resin layer 1 of the winding core member 10 of the present disclosure has adhesive properties to metal, a member containing metal is preferable. For example, the positive electrode plate may be arranged so as to be in contact with the surface of the winding core 11, and then the separator and the negative electrode plate may be arranged on the outside in that order. Alternatively, the negative electrode plate may be arranged so as to be in contact with the surface of the winding core 11, and then the separator and the positive electrode plate may be arranged on the outside in that order. The end of the storage element (i.e., the end of the positive electrode plate, negative electrode plate, or separator) and the metal adhesive resin layer 1 of the core member 10 of the present disclosure (the metal adhesive resin layer 1 of the core 11) can be fixed by bonding such as heat fusion.

[0117] With the positive electrode plate, negative electrode plate, and separator arranged on the winding core 11, the rotating shaft of the winding device is rotated to a predetermined number of rotations, and the positive electrode plate, negative electrode plate, and separator wound on the outer peripheral surface of the winding core 11 are removed from the rotating shaft, thereby obtaining a winding core-equipped storage element of the present disclosure, which comprises the winding core 11 and the storage element.

[0118] The positive electrode plate, negative electrode plate, and separator that form the electricity storage element may be appropriately selected depending on the type of electricity storage device, and are not particularly limited.

[0119] The positive electrode plate is manufactured, for example, as follows: x MO yA cathode active material such as a lithium transition metal composite oxide represented by LiMePO4 (where M represents at least one transition metal) or an olivine-structured compound represented by LiMePO4 (where Me is, for example, Fe, Mn, Co, or Cr) is mixed in a predetermined mass ratio with a conductive material such as acetylene black or carbon black, and a binder such as polyvinylidene fluoride. N-methyl-2-pyrrolidone or the like is added to this mixture to adjust the viscosity, resulting in a cathode mixture paste. This cathode mixture paste is then applied to both sides of a cathode current collector selected from aluminum foil, aluminum alloy foil, nickel foil, or the like. After application, the cathode mixture paste is dried and rolled to a predetermined thickness to obtain a cathode plate.

[0120] The negative electrode plate is manufactured, for example, as follows: A carbon material such as coke, non-graphitizable carbon, or graphite including artificial graphite and natural graphite is mixed with a binder such as polyvinylidene fluoride in a predetermined mass ratio. N-methyl-2-pyrrolidone or the like is added to this mixture to adjust the viscosity, resulting in a negative electrode mixture paste. This negative electrode mixture paste is then applied to both sides of a negative electrode current collector made of copper foil or the like. After application, the negative electrode mixture paste is dried and rolled to a predetermined thickness to obtain a negative electrode plate.

[0121] The separator physically separates the positive and negative electrodes and holds the electrolyte in the micropores of the separator, which is typically a microporous membrane made of a polyolefin resin such as polyethylene or polypropylene.

[0122] 4. Energy storage devices The electricity storage device of the present disclosure includes an electricity storage element and a winding core member of the present disclosure disposed on a winding shaft portion of the electricity storage element. In the electricity storage device of the present disclosure, the electricity storage element and the winding core member of the present disclosure are sealed with an exterior material. As described above, the end of the electricity storage element (i.e., the end of the positive electrode plate, negative electrode plate, or separator) and the metal adhesive resin layer 1 of the winding core member 10 of the present disclosure (the metal adhesive resin layer 1 of the winding core 11) can be fixed by bonding such as heat fusion.

[0123] The positive electrode plate of the electricity storage element is electrically connected to a positive electrode terminal, and the negative electrode plate of the electricity storage element is electrically connected to a negative electrode terminal. The electricity storage element with the connected positive electrode terminal and negative electrode terminal is housed in an exterior packaging material, and the opening of the exterior packaging material is fitted with a lid and welded. An electrolyte is housed inside the exterior packaging material together with the electricity storage element, and the opening is sealed to obtain an electricity storage device.

[0124] As the exterior material, an exterior material for an electricity storage device can be used. The exterior material for an electricity storage device is not particularly limited as long as it is used as an exterior material for an electricity storage device. Examples of exterior materials for electricity storage devices include metal cans made of stainless steel, aluminum alloys, etc. Further, examples of exterior materials for electricity storage devices include those having a laminate structure (laminated film) made of a laminate having at least a substrate, a barrier layer, and a heat-sealable resin layer in this order.

[0125] As these packaging materials, known materials can be used. A brief description will be given below of packaging materials for electricity storage devices having a laminate structure composed of a laminate having at least a substrate, a barrier layer, and a heat-sealable resin layer in this order.

[0126] (Exterior materials for energy storage devices) The electrical storage device packaging material may have a laminated structure consisting of a laminate having at least a substrate, a barrier layer, and a heat-sealable resin layer in this order. An example of the cross-sectional structure of the electrical storage device packaging material is a configuration in which a substrate, an optional adhesive layer, a barrier layer, an optional adhesive layer, and a heat-sealable resin layer are laminated in this order. In the electrical storage device packaging material, the substrate is the outer layer, and the heat-sealable resin layer is the innermost layer. When assembling the electrical storage device, the heat-sealable resin layers located on the periphery of the electrical storage element are brought into contact with each other and heat-sealed to seal the electrical storage element, thereby sealing the electrical storage element. The electrical storage device packaging material may be an embossed type formed by embossing or the like. Alternatively, the electrical storage device packaging material may be an unformed pouch type. Pouch types include three-sided seal, four-sided seal, and pillow type, and any of these types may be used.

[0127] The thickness of the laminate constituting the electrical storage device exterior material is not particularly limited, but from the viewpoint of cost reduction, improvement of energy density, etc., examples include about 300 μm or less, preferably about 250 μm or less, about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the electrical storage device exterior material to protect the electrical storage elements, the thickness of the laminate constituting the electrical storage device exterior material is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 155 μm or more, and about 190 μm or more. Furthermore, preferred ranges for the laminate constituting the packaging material for an electricity storage device include, for example, about 35 to 300 μm, about 35 to 250 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 300 μm, about 45 to 250 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 300 μm, and 60 to 250 μm. In particular, when making an electricity storage device lighter and thinner, about 60 to 155 μm is preferred, and when improving formability, about 155 to 190 μm is preferred.

[0128] (base material) In the packaging material for an electricity storage device, the substrate is a layer that functions as a support for the packaging material for an electricity storage device and is a layer that forms the outermost layer side.

[0129] The material forming the substrate is not particularly limited, as long as it has insulating properties. Examples of materials forming the substrate include polyester, polyamide, epoxy, acrylic resin, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, and mixtures or copolymers thereof. Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantage of being highly resistant to electrolyte and being less likely to cause whitening due to adhesion of electrolyte, and are therefore preferably used as materials forming the substrate. Furthermore, polyamide film has excellent stretchability and can prevent whitening due to cracking of the resin in the substrate during molding, and is therefore preferably used as a material forming the substrate.

[0130] The substrate may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film, is preferably used as the substrate because its heat resistance is improved by oriented crystallization.

[0131] Among these, the resin film forming the substrate is preferably nylon or polyester, and more preferably biaxially oriented nylon or biaxially oriented polyester.

[0132] The substrate may be laminated with resin films made of different materials to improve pinhole resistance and insulation when used as a package for an electricity storage device. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated together, or a multilayer structure in which a biaxially oriented polyester film and a biaxially oriented nylon film are laminated together. When the substrate has a multilayer structure, the resin films may be bonded together via an adhesive, or may be directly laminated together without an adhesive. When bonding without an adhesive, examples include methods of bonding in a hot-melt state, such as coextrusion, sand lamination, and thermal lamination.

[0133] The thickness of the substrate may be, for example, about 3 to 50 μm, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 10 to 50 μm, about 10 to 35 μm, or about 10 to 11 μm.

[0134] (adhesive layer) In the packaging material for an electricity storage device, the adhesive layer is a layer that is disposed on the substrate as needed to impart adhesion to the substrate, i.e., the adhesive layer is provided between the substrate and the barrier layer.

[0135] The adhesive layer is formed from an adhesive capable of bonding the substrate and the barrier layer. The adhesive used to form the adhesive layer may be a two-component curing adhesive or a one-component curing adhesive. The adhesive mechanism of the adhesive used to form the adhesive layer is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, or the like.

[0136] The resin component of the adhesive that can be used to form the adhesive layer is preferably a polyurethane-based two-component curing adhesive; or a blend resin of polyamide, polyester, or a modified polyolefin, from the viewpoint of excellent ductility, durability under high humidity conditions, yellowing prevention, and thermal degradation prevention during heat sealing, and of effectively suppressing a decrease in the laminate strength between the substrate and the barrier layer and preventing delamination.

[0137] The adhesive layer may be multi-layered with different adhesive components. When the adhesive layer is multi-layered with different adhesive components, it is preferable to select a resin with excellent adhesion to the substrate as the adhesive component disposed on the substrate side, and an adhesive component with excellent adhesion to the barrier layer as the adhesive component disposed on the barrier layer side, from the viewpoint of improving the laminate strength between the substrate and the barrier layer. When the adhesive layer is multi-layered with different adhesive components, specific examples of the adhesive component disposed on the barrier layer side include preferably acid-modified polyolefin, metal-modified polyolefin, a mixed resin of polyester and acid-modified polyolefin, and a resin containing a copolymer polyester. Examples of acid-modified polyolefin include the same as those exemplified for the metal adhesive resin layer 1.

[0138] The thickness of the adhesive layer is, for example, about 2 to 50 μm, and preferably about 3 to 25 μm.

[0139] (barrier layer) In the packaging material for an electrical storage device, the barrier layer is a layer that not only improves the strength of the packaging material for an electrical storage device but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the interior of the electrical storage device. The barrier layer is preferably a metal layer, i.e., a layer formed of a metal. Specific examples of metals constituting the barrier layer include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with these vapor deposition films. It is preferably formed from a metal foil, and more preferably from an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer during the production of the packaging material for an electricity storage device, it is more preferable that the barrier layer be formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0140] The thickness of the barrier layer is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, or about 65 to 85 μm, from the viewpoint of making the packaging material for an electricity storage device thinner while making it less likely to produce pinholes during molding.

[0141] Furthermore, it is preferable that at least one surface, and preferably both surfaces, of the barrier layer be chemically treated in order to stabilize adhesion, prevent dissolution and corrosion, etc. Here, chemical treatment refers to a treatment for forming a corrosion-resistant film on the surface of the barrier layer.

[0142] (adhesive layer) In the packaging material for an electricity storage device, the adhesive layer is a layer that is provided as needed between the barrier layer and the heat-sealable resin layer in order to firmly bond the heat-sealable resin layer.

[0143] The adhesive layer is formed from an adhesive capable of bonding the barrier layer and the heat-sealable resin layer. The composition of the adhesive used to form the adhesive layer is not particularly limited, but examples thereof include a resin composition containing an acid-modified polyolefin. Examples of acid-modified polyolefins include the same ones exemplified for the metal adhesive resin layer 1.

[0144] The thickness of the adhesive layer is, for example, about 1 to 40 μm, and preferably about 2 to 30 μm.

[0145] (thermal adhesive resin layer) In the packaging material for an electricity storage device, the heat-sealable resin layer corresponds to the innermost layer, and is a layer that seals the electricity storage element by heat-sealing the heat-sealable resin layers together when the electricity storage device is assembled.

[0146] The resin component used in the heat-fusible resin layer is not particularly limited as long as it is heat-fusible, and examples thereof include polyolefins and cyclic polyolefins.

[0147] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0148] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred. Styrene is also an example of a constituting monomer.

[0149] Among these resin components, preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blend polymers thereof; more preferred are polyethylene, polypropylene, copolymers of ethylene and norbornene, and blend polymers of two or more of these.

[0150] The heat-fusible resin layer may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components.Furthermore, the heat-fusible resin layer may be formed of only one layer, or may be formed of two or more layers of the same or different resin components.

[0151] The thickness of the heat-sealable resin layer is not particularly limited as long as it functions to heat-seal the heat-sealable resin layers together and seal the electricity storage element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. Note that, for example, when the thickness of the adhesive layer described below is 10 μm or more, the thickness of the heat-sealable resin layer is preferably about 85 μm or less, more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer described below is less than 10 μm or when no adhesive layer is provided, the thickness of the heat-sealable resin layer is preferably about 20 μm or more, more preferably about 35 to 85 μm.

[0152] The winding core member of the present disclosure can be suitably used in electricity storage devices such as batteries (including condensers, capacitors, etc.). The winding core member of the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the winding core member of the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the winding core member of the present disclosure. [Example]

[0153] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0154] <Manufacturing of core components> Example 1 A film was prepared as the substrate layer, in which a polyethylene terephthalate (PET) film (125 μm thick) and a non-oriented polypropylene (CPP) film (50 μm thick) were laminated with an adhesive layer (a cured two-component urethane adhesive, 3 μm thick) interposed between them. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the non-oriented polypropylene (CPP) side of the substrate layer to form a metal adhesive resin layer (20 μm thick), and a core member was produced in which the substrate layer (PET film / adhesive layer / CPP film) / metal adhesive resin layer (PPa) were laminated in this order.

[0155] Example 2 A film was prepared as the substrate layer, in which a polyethylene terephthalate (PET) film (thickness 188 μm) and an unstretched polypropylene (CPP) film (thickness 50 μm) were laminated with an adhesive layer (a cured product of a two-component urethane adhesive, thickness 3 μm) interposed therebetween. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the unstretched polypropylene (CPP) side of the substrate layer to form a metal adhesive resin layer (thickness 20 μm), and a core member was produced in which the substrate layer (PET film / adhesive layer / CPP film) / metal adhesive resin layer (PPa) were laminated in this order.

[0156] Example 3 A film was prepared as the substrate layer, in which a polyethylene terephthalate (PET) film (125 μm thick) and a polyethylene terephthalate (PET) film (100 μm thick) were laminated with an adhesive layer (a cured two-component urethane adhesive, 3 μm thick) interposed between them. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the substrate layer facing the polyethylene terephthalate (PET) film to form a metal adhesive resin layer (20 μm thick), and a core member was produced in which the substrate layer (PET film / adhesive layer / PET film) / metal adhesive resin layer (PPa) were laminated in this order.

[0157] Example 4 A film was prepared as the substrate layer, in which a polyethylene terephthalate (PET) film (188 μm thick) and a polyethylene terephthalate (PET) film (100 μm thick) were laminated with an adhesive layer (a cured two-component urethane adhesive, 3 μm thick) interposed between them. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the polyethylene terephthalate (PET) film side of the substrate layer to form a metal adhesive resin layer (20 μm thick), and a core member was produced in which the substrate layer (PET film / adhesive layer / PET film) / metal adhesive resin layer (PPa) were laminated in this order.

[0158] Example 5 A film was prepared as the substrate layer, in which an aluminum alloy foil (ALM, thickness 80 μm) and a polyethylene terephthalate (PET) film (thickness 50 μm) were laminated via an adhesive layer (a cured two-component urethane adhesive, thickness 3 μm). A metal adhesive resin layer (thickness 20 μm) was formed on the surface of the polyethylene terephthalate (PET) film side of the substrate layer by melt-extruding maleic anhydride-modified polypropylene (PPa), and a core member was produced in which the substrate layer (ALM / adhesive layer / PET film) / metal adhesive resin layer (PPa) were laminated in this order.

[0159] Example 6 A film was prepared as the substrate layer, in which an aluminum alloy foil (ALM, thickness 80 μm) and a polyethylene terephthalate (PET) film (thickness 100 μm) were laminated with an adhesive layer (a cured two-component urethane adhesive, thickness 3 μm) interposed between them. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the polyethylene terephthalate (PET) film side of the substrate layer to form a metal adhesive resin layer (thickness 20 μm), and a core member was produced in which the substrate layer (ALM / adhesive layer / PET film) / metal adhesive resin layer (PPa) were laminated in this order.

[0160] Example 7 A film was prepared as the substrate layer, in which an aluminum alloy foil (ALM, thickness 80 μm) and a non-oriented polypropylene (CPP) film (thickness 50 μm) were laminated via an adhesive layer (a cured two-component urethane adhesive, thickness 3 μm). A metal adhesive resin layer (thickness 20 μm) was formed on the surface of the non-oriented polypropylene (CPP) film side of the substrate layer by melt-extruding maleic anhydride-modified polypropylene (PPa), and a core member was produced in which the substrate layer (ALM / adhesive layer / CPP film) / metal adhesive resin layer (PPa) were laminated in this order.

[0161] Example 8 An aluminum alloy foil (ALM, thickness 80 μm) was prepared as the substrate layer. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the substrate layer to form a metal-adhesive resin layer (thickness 80 μm), and a core member was produced in which the substrate layer (ALM) / metal-adhesive resin layer (PPa) were laminated in this order.

[0162] Example 9 A film was prepared as the substrate layer, in which stainless steel foil (SUS, 60 μm thick) and unstretched polypropylene (CPP) film (80 μm thick) were laminated via an adhesive layer (a cured two-component urethane adhesive, 3 μm thick). Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the unstretched polypropylene (CPP) film side of the substrate layer to form a metal adhesive resin layer (20 μm thick), and a core member was produced in which the substrate layer (SUS / adhesive layer / CPP film) / metal adhesive resin layer (PPa) were laminated in this order.

[0163] Example 10 A stainless steel foil (SUS, thickness 60 μm) was prepared as the substrate layer. Maleic anhydride-modified polypropylene (PPa) was melt-extruded onto the surface of the substrate layer to form a metal-adhesive resin layer (thickness 80 μm), and a core member was produced in which the substrate layer (SUS) / metal-adhesive resin layer (PPa) were laminated in this order.

[0164] Example 11 A maleic anhydride-modified polypropylene (PPa) film (thickness: 80 μm) was prepared as a metal adhesive resin layer and used as a core member.

[0165] Comparative Example 1 Copper foil (thickness: 70 μm) was prepared as a core member.

[0166] Comparative Example 2 A film was prepared in which a polyethylene terephthalate (PET) film (12 μm thick) and an oriented nylon (ONy) film (15 μm thick) were laminated via an adhesive layer (a cured product of a two-component urethane adhesive, 3 μm thick). The oriented nylon (ONy) film of this film was laminated with an aluminum alloy foil (ALM, 40 μm thick) via an adhesive layer (a cured product of a two-component urethane adhesive, 3 μm thick). Next, maleic anhydride-modified polypropylene (PPa, 40 μm thick) and random polypropylene (PP, 40 μm thick) were co-extruded onto the aluminum alloy foil of each of the resulting laminates to produce a core member laminated in the following order: PET / adhesive layer / ONy / adhesive layer / ALM / PPa / PP.

[0167] <Rigidity of core material> The rigidity of the core member was measured under the following conditions, and the results are shown in Table 1. (Rigidity measurement conditions) Measurement equipment: Universal testing equipment (Autograph Shimadzu AG-X Plus tensile testing machine) Measurement sample size: MD 100mm, TD 15mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: As shown in the schematic diagram of Figure 8, both ends in the MD direction of the measurement sample (winding core member 10) are attached to the lower chuck 32 of the universal testing machine, and the measurement sample is set in a loop shape. The upper chuck 31 of the universal testing machine is lowered at a constant speed of 50 m / min. The load (N / 15 mm) at the point when the upper chuck 31 has pressed the loop-shaped measurement sample 25 mm is taken as the rigidity value.

[0168] <Deadhold performance of core components> The angle of the bent portion of the core member was measured under the following measurement conditions, and the deadhold property was evaluated. The evaluation criteria are as described below. The results are shown in Table 1. (Conditions for measuring the angle of the bent part) Measuring device: glass plate and roller with a mass of 2 kg Measurement sample size: MD 200mm, TD 100mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: The measurement sample is folded in half in the MD direction so that the metal adhesive resin layers face each other. A roller with a mass of 2 kg is placed on the folded portion and the roller is moved back and forth five times in the TD direction. The measurement sample is placed on the glass plate so that the surface of the metal adhesive resin layer of the measurement sample is perpendicular to the surface of the glass plate, and allowed to stand for 1 minute. The angle of the folded portion of the measurement sample on the glass plate side is measured, and the dead hold ability is evaluated according to the following criteria. (Deadholdability evaluation criteria) A: The angle of the bent part is between 0° and 45° B: The angle of the bent part is 45° or more and less than 90° C: The angle of the bent part is 90° or more and less than 125° D: The angle of the bent part is between 125° and 180°

[0169] [Table 1]

[0170] As shown in Table 1, the surface of the winding core members of Examples 1 to 11 facing the electricity storage element was formed of a metal adhesive resin layer. The winding core members of Examples 1 to 11 can improve the production efficiency of electricity storage devices.

[0171] As described above, the present disclosure provides the following aspects of the invention. Item 1. A core member disposed on a winding shaft of an electricity storage element of an electricity storage device, The surface of the winding core member on the side of the electric storage element is formed of a metal adhesive resin layer. Item 2. The winding core member according to Item 1, wherein the winding core member is composed of a laminate including a base material layer and the metal-adhesive resin layer. Item 3. The core member according to Item 2, wherein the base layer contains at least one of a metal and a resin. Item 4. The core member according to any one of Items 1 to 3, wherein the metal-adhesive resin layer contains at least one selected from the group consisting of modified polyolefins and polyesters. Item 5. The winding core member according to any one of Items 1 to 4, wherein the thickness of the metal-adhesive resin layer is 20 μm or more and 100 μm or less. Item 6. The core member according to any one of Items 1 to 5, having a rigidity of 0.4 N / 15 mm or more as measured under the following measurement conditions. (Rigidity measurement conditions) Measuring equipment: Universal testing equipment (autograph) Measurement sample size: MD 100mm, TD 15mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: Attach both ends of the measurement sample in the MD direction to the universal testing machine chuck, and set the measurement sample in a loop shape. The upper chuck of the universal testing machine is lowered at a constant speed of 50 m / min. The load (N / 15 mm) at the point when the upper chuck has pressed the loop-shaped measurement sample 25 mm is taken as the rigidity value. Item 7. The core member according to any one of Items 1 to 6, wherein the angle of the bent portion measured under the following measurement conditions is 90° or less. (Conditions for measuring the angle of the bent part) Measuring device: glass plate and roller with a mass of 2 kg Measurement sample size: MD 200mm, TD 100mm Measurement environment: Temperature 23°C, relative humidity 46% Measurement method: The measurement sample is folded in half in the MD direction so that the metal adhesive resin layers face each other. A roller with a mass of 2 kg is placed on the folded portion and the roller is moved back and forth five times in the TD direction. The measurement sample is placed on the glass plate so that the surface of the metal adhesive resin layer of the measurement sample is perpendicular to the surface of the glass plate, and allowed to stand for 1 minute. The angle of the folded portion of the measurement sample on the glass plate side is measured. Item 8. A winding core for an electricity storage device, comprising the winding core member according to any one of Items 1 to 7. Item 9. A winding core for an electricity storage device, which is obtained by forming the winding core member according to any one of Items 1 to 8 into a cylindrical shape. Item 10. A winding core for an electricity storage device, in which the winding core member according to any one of Items 1 to 9 is disposed on the outer periphery of a cylindrical metal member. Item 11. The winding core of the electricity storage device according to claim 10, wherein the metal member includes at least one selected from the group consisting of aluminum, copper, stainless steel, iron, steel, and magnesium. Item 12. The winding core for an electricity storage device according to Item 10 or 12, wherein the thickness of the metal member is 50 μm or more and 200 μm or less. Item 13. A core-attached electricity storage element, comprising the core according to Item 8 on a winding shaft portion of the electricity storage element. Item 14. The core-attached electricity storage element according to Item 13, wherein an end of the electricity storage element and the metal-adhesive resin layer of the core member are joined together. Item 15. An electricity storage device comprising an electricity storage element and a winding core member disposed on a winding shaft portion of the electricity storage element, The surface of the core member on the side of the storage element is formed of a metal adhesive resin layer. Item 16. The electricity storage device according to Item 15, wherein an end of the electricity storage element and the metal adhesive resin layer of the winding core member are joined together. [Explanation of symbols]

[0172] 1 Metal adhesive resin layer 2 Base material layer 3 Barrier layer 10 Core members 10a: Surface of the core member on the storage element side 11 Core 12 Metallic parts 21 Resin layer 22 Metal layer 23 Adhesive layer 31 Upper chuck 32 Lower zipper

Claims

1. A core member disposed on a winding shaft portion of an electricity storage element of an electricity storage device, a surface of the core member on the side of the storage element is formed of a metal adhesive resin layer, A core member having a bent portion with an angle of 90° or less, as measured under the following measurement conditions: (Conditions for measuring the angle of the bent part) Measuring equipment: glass plate and roller with a mass of 2 kg Measurement sample size: MD 200 mm, TD 100 mm Measurement environment: temperature 23°C, relative humidity 46% Measurement method: The measurement sample is folded in half in the MD direction so that the metal adhesive resin layers face each other. A roller with a mass of 2 kg is placed on the bent portion and the roller is moved back and forth five times in the TD direction. The measurement sample is placed on the glass plate so that the surface of the metal-adhesive resin layer of the measurement sample is perpendicular to the surface of the glass plate, and allowed to stand for 1 minute. The angle of the bent portion of the measurement sample on the glass plate side is measured.

2. The winding core member according to claim 1 , wherein the winding core member is composed of a laminate including a base material layer and the metal-adhesive resin layer.

3. The core member according to claim 2 , wherein the base material layer contains at least one of a metal and a resin.

4. 3. The winding core member according to claim 1 or 2, wherein the metal adhesive resin layer contains at least one selected from the group consisting of modified polyolefin, polyester, silicone resin, phenolic resin, methacrylic resin, ester resin, amino resin, fluororesin, vinyl ester resin, polyvinyl alcohol resin, polyurethane resin, polystyrene resin, epoxy resin, urethane epoxy resin, and silicone epoxy resin.

5. 3. The core member according to claim 1, wherein the thickness of the metal adhesive resin layer is 20 μm or more and 100 μm or less.

6. 3. The core member according to claim 1, wherein the stiffness measured under the following conditions is 0.4 N / 15 mm or more. (Conditions for measuring rigidity) Measuring equipment: Universal testing equipment (autograph) Measurement sample size: MD 100 mm, TD 15 mm Measurement environment: temperature 23°C, relative humidity 46% Measurement method: Both ends of the measurement sample in the MD direction are attached to the chuck of a universal testing machine, and the measurement sample is set in a loop shape. The upper chuck of the universal testing machine is lowered at a constant speed of 50 m / min. The load (N / 15 mm) at the point when the upper chuck presses the loop-shaped measurement sample 25 mm is taken as the rigidity value.

7. A winding core for an electricity storage device, comprising the winding core member according to claim 1 or 2.

8. A winding core for an electricity storage device, the winding core member according to claim 1 or 2 being formed into a cylindrical shape.

9. A winding core for an electricity storage device, comprising the winding core member according to claim 1 or 2 disposed on the outer periphery of a cylindrical metal member.

10. The winding core for an electricity storage device according to claim 9 , wherein the metal member includes at least one selected from the group consisting of aluminum, copper, stainless steel, iron, steel, and magnesium.

11. The winding core for an electricity storage device according to claim 9 , wherein the metal member has a thickness of 50 μm or more and 200 μm or less.

12. A winding core for an electricity storage device, wherein a winding core member disposed on a winding shaft portion of an electricity storage element of the electricity storage device is disposed on the outer periphery of a cylindrical metal member, The thickness of the metal member is 50 μm or more and 200 μm or less, a surface of the core member on the side of the storage element is formed of a metal adhesive resin layer, The core member has a rigidity of 0.4 N / 15 mm or more as measured under the following measurement conditions: The winding core of an electricity storage device. (Conditions for measuring rigidity) Measuring equipment: Universal testing equipment (autograph) Measurement sample size: MD 100 mm, TD 15 mm Measurement environment: temperature 23°C, relative humidity 46% Measurement method: Both ends of the measurement sample in the MD direction are attached to the chuck of a universal testing machine, and the measurement sample is set in a loop shape. The upper chuck of the universal testing machine is lowered at a constant speed of 50 m / min. The load (N / 15 mm) at the point when the upper chuck presses the loop-shaped measurement sample 25 mm is taken as the rigidity value.

13. A core-attached electricity storage element, comprising the core according to claim 7 on a winding shaft portion of the electricity storage element.

14. The core-attached electricity storage element according to claim 13 , wherein an end of the electricity storage element and the metal-adhesive resin layer of the core member are joined together.

15. An electricity storage device comprising: an electricity storage element; and the winding core member according to claim 1 or 2, which is disposed on a winding shaft portion of the electricity storage element, The surface of the core member on the side of the storage element is formed of a metal adhesive resin layer. Energy storage device.

16. The electricity storage device according to claim 15 , wherein an end of the electricity storage element and the metal adhesive resin layer of the winding core member are joined together.

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