METHOD FOR PRODUCING AN ENERGY STORAGE DEVICE, AND ENERGY STORAGE DEVICE

Abstract

A method for manufacturing an energy storage device including a battery, injection holes, a tubular member surrounding the injection holes, and a laminate film includes a step of bringing the laminate film into contact with the tubular member and welding them by hot pressing. On the tubular member, a first region including a surface contacting the laminate film is patterned with resin L, and a second region, which is located farther toward the injection holes than the first region and contacting the first region, is patterned with resin H. The melting points Tm or glass transition temperatures Tg of resin L and resin Ia m are lower than those of resin H.A hot pressing temperature is higher than or equal to the melting point Tm or the glass transition temperature Tg of the resin L and the resin Iam and is lower than the melting point Tm or the glass transition temperature Tg of the resin H.

Description

BACKGROUNDTechnical FieldThe present disclosure relates to an energy storage device manufacturing method and an energy storage device.Prior ArtEnergy storage devices including a battery, injection ports for injecting an electrolyte liquid into the battery, and a tubular member surrounding the injection ports have been conventionally used.For example, Japanese Patent Application Laid-Open (JP-A) No. 2020-173921 discloses a method for manufacturing an energy storage module, which includes a welding step of joining and integrating a module main body with a sealing member and a pressure adjusting valve with a housing by heating element welding. In the welding step, using a heater welding device including a housing main body and a thin plate-shaped cover plate formed of a rigid body having high thermal conductivity and detachably mounted on the housing main body, connection protrusions of the sealing member and connection protrusions of the housing are each formed to abut on the outer surface of the cover plate. At the time when the connection protrusions are heated and melted so that the melted amounts thereof become amounts respectively set in advance, the connection protrusions are moved away from the outer surface of the cover plate, and then the connection protrusions and the connection protrusions are made to contact each other under pressure.SUMMARYIn conventional methods for manufacturing energy storage devices, particularly methods for manufacturing an energy storage device in which the entire tubular member surrounding the injection ports is formed of a kind of resin, voids may be formed in the tubular member when a laminate film and the tubular member are welded by hot pressing. The reason why voids are formed is presumed to be as follows. On the tubular member, the resin located near the surface coming into contact with the laminate film is melted by the hot pressing, and the flowability of the member increases. In this state, when the tubular member is pushed in the direction in which the pressure is applied in the hot presses, the internal pressure of the spaces inside the tubular member increases. Since the internal pressure becomes too high, the air in the spaces breaks and bulges out melted portions of the resin structuring the tubular member. As a result, cavities can be formed at the locations of the tubular element which are broken by the air in the spaces.The present disclosure has been made in view of the above-described circumstances, and an object thereof is to provide an energy storage device manufacturing method that can obtain good sealability of the spaces inside a tubular member that communicate with injection ports, and an energy storage device that can obtain good sealability of the spaces inside a tubular member that communicate with ports that communicate with the inside of a battery.Means for achieving the above-described object include the following aspects.A method of manufacturing an energy storage device of a first aspect of the present disclosure including a battery, injection ports for injecting an electrolyte liquid into the battery, a tubular member surrounding the injection ports, and a laminate film welded to the tubular member, and sealing spaces inside the tubular member communicating with the injection ports, the method comprising:a step of welding the tubular member and the laminate film by bringing the laminate film into contact with the tubular member and performing hot pressing from the laminate film side,whereinthe tubular member has a first region including a surface contacting the laminate film structured by resin L and a second region disposed further toward the injection ports side than the first region and contacting the first region structured by resin H, and the laminate film has a third region including a surface contacting the tubular member structured by resin lam, andMelting points Tm or glass transition temperatures Tg of the resin L, the resin H and the resin Lam satisfy the following conditions a, b and c. a: The melting point Tm or the glass transition temperature Tg of the resin L is lower than the melting point Tm or the glass transition temperature Tg of the resin H. b: The melting point Tm or the glass transition temperature Tg of the resin lam is lower than the melting point Tm or the glass transition temperature Tg of the resin H. c: A temperature of hot pressing is higher than or equal to the melting point Tm or the glass transition temperature Tg of the resin L, is higher than or equal to the melting point Tm or the glass transition temperature Tg of the resin lam, and is lower than the melting point Tm or the glass transition temperature Tg of the resin H.The method for manufacturing an energy storage device of a second aspect according to the present disclosure is the method for manufacturing an energy storage device of the first aspect, wherein the resin H is polypropylene and the resin L and the resin lam are polyethylene.The method for manufacturing an energy storage device of a third aspect according to the present disclosure is the method for manufacturing an energy storage device of the first aspect or the second aspect, wherein a shape of the battery is rectangular as viewed in a thickness direction of the battery, and the lengths of the sides of the rectangle are a height of greater than or equal to 1000 mm and a width of greater than or equal to 10,000 mm.The method for manufacturing an energy storage device of a fourth aspect according to the present disclosure is the method for manufacturing an energy storage device of any one of the first aspect to the third aspect, wherein the tubular member has convex / concave shapes on surfaces at which the second region and the first region contact each other.The method for manufacturing an energy storage device of a fifth aspect according to the present disclosure is the method for manufacturing an energy storage device of any one of the first aspect to the third aspect, wherein on the tubular member, the surfaces at which the second region and the first region contact each other are shapes that snap at a time when the first region is strained in a direction toward a side opposite to the injection ports.An energy storage device according to a sixth aspect of the present disclosure includes:a battery;openings communicating with an interior of the battery;a tubular member surrounding the openings; anda laminate film welded to the tubular member and sealing spaces inside the tubular member communicating with the openings,whereinon the tubular member, a first region including a surface contacting the laminate film is structured by resin L and a second region disposed further toward the side of the openings than the first region and contacting the first region is structured by resin H, and on the laminate film, a third region including a surface contacting the tubular member is structured by resin lam, andMelting points Tm or glass transition temperatures Tg of the resin L, the resin H and the resin lam satisfy the following conditions a and b. a: The melting point Tm or the glass transition temperature Tg of the resin L is lower than the melting point Tm or the glass transition temperature Tg of the resin H. b: The melting point Tm or the glass transition temperature Tg of the resin lam is lower than the melting point Tm or the glass transition temperature Tg of the resin H.The energy storage device of a seventh aspect according to the present disclosure is the energy storage device of the sixth aspect, wherein the resin H is polypropylene and the resin L and the resin lam are polyethylene.The energy storage device of an eighth aspect according to the present disclosure is the energy storage device of the sixth aspect or the seventh aspect, wherein a shape of the energy storage device is rectangular as viewed in a thickness direction of the energy storage device, and the lengths of the sides of the rectangle are a height greater than or equal to 1000 mm and a width greater than or equal to 10,000 mm.The energy storage device of a ninth aspect according to the present disclosure is the energy storage device of any one of the sixth to eighth aspects, wherein the tubular member has convex / concave shapes on surfaces at which the second region and the first region contact each other.The energy storage device of a tenth aspect according to the present disclosure is the energy storage device of any one of the sixth aspects to the eighth aspect, wherein, on the tubular member, the surfaces at which the second region and the first region contact each other are shapes that snap at a time when the first region is biased in a direction toward a side opposite to the openings.According to the present disclosure, there are provided an energy storage device manufacturing method that can obtain good sealability of the spaces inside a tubular member communicating with injection ports, and an energy storage device that can obtain good sealability of the spaces inside a tubular member communicating with ports communicating with the inside of a battery.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic perspective view illustrating an example of an energy storage device related to an embodiment of the present disclosure; FIG. 2 is an exploded perspective view illustrating a portion of the energy storage device related to the embodiment of the present disclosure illustrated in FIG. 1 ; FIG. 3 is a schematic sectional view illustrating a portion of the present invention.This is an energy storage device related to the embodiment of the present disclosure illustrated in FIG. 1 ; FIG. 4 is a schematic sectional view illustrating an example of a step of an energy storage device manufacturing method related to an embodiment of the present disclosure. FIG. 5 is a schematic cross-sectional view illustrating another example of an energy storage device related to the embodiment of the present disclosure. FIG. 6 is a schematic cross-sectional view illustrating another example of an energy storage device related to the embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view illustrating another example of an energy storage device related to the embodiment of the present disclosure. FIG. 8 is a schematic cross-sectional view illustrating another example of an energy storage device related to the embodiment of the present disclosure. FIG. 9 is a schematic cross-sectional view illustrating another example of an energy storage device related to the embodiment of the present disclosure.DETAILED DESCRIPTIONEmbodiments that are examples of the present disclosure will be described below. The explanations and examples are illustrative of embodiments and do not limit the scope of the invention. In numerical value ranges indicated stepwise in the present specification, the maximum value or the minimum value of a certain numerical value range may be replaced with the maximum value or the minimum value of another numerical value range indicated stepwise. Further, the maximum or minimum values of the numerical value ranges mentioned in the present specification may be replaced with the values indicated in the examples.Each component may comprise a plurality of respective materials. In a case where there are plural kinds of substances corresponding to one component in a composition, the amount of this component in the composition means the total amount of the plural kinds of substances present in the composition on average unless otherwise stated. "Step" is not only a stand-alone step and also includes steps which, even if this step cannot be clearly distinguished from another step, achieve the purpose followed by this step.Energy storage device and method for manufacturing the same> A method for manufacturing an energy storage device relating to an embodiment of the present disclosure is a method for manufacturing an energy storage device including a battery, injection ports for supplying an electrolyte liquid into the battery, a tubular member surrounding the injection ports, and a laminate film welded to the tubular member, and seals spaces inside the tubular member communicating with the injection ports.This energy storage device manufacturing method has a step of welding the tubular member and the laminate film by bringing the laminate film into contact with the tubular member and performing hot pressing from the laminate film side.At the tubular member, a first region including the surface contacting the laminate film is patterned by resin L, and a second region which is disposed further toward the injection port side than the first region and which contacts the first region is patterned by resin H.The melting points Tm or glass transition temperatures Tg of resin L, resin H and resin lam satisfy the following conditions a, b and c. a: The melting point Tm or glass transition temperature Tg of resin L is lower than the melting point Tm or glass transition temperature Tg of resin H. b: The melting point Tm or glass transition temperature Tg of resin lam is lower than the melting point Tm or glass transition temperature Tg of resin H. c: The temperature of hot pressing is higher than or equal to the melting point Tm or glass transition temperature Tg of resin L, is higher than or equal to the melting point Tm or glass transition temperature Tg of resin lam, and is lower than the melting point Tm or glass transition temperature Tg of resin H.An energy storage device related to an embodiment of the present disclosure includes a battery, openings communicating with an internal space of the battery, a tubular member surrounding the openings, and a laminate film welded to the tubular member and sealing spaces inside the tubular member communicating with the openings. At the tubular member, a first region including the surface contacting the laminate film is patterned by resin L, and a second region disposed further toward the opening side than the first region and contacting the first region is patterned by resin H. On the laminate film, a third region including the surface contacting the tubular member is structured by resin lam. The melting points Tm or glass transition temperatures Tg of resin L, resin H, and resin lam satisfy the above-described conditions a and b. The openings are not particularly limited as long as they are communicated with the inside of the battery, such as injection openings.There are cases where the "ports" are simply referred to as "injection ports". Further, there are cases where the "tubular member" is simply referred to as an "injection port frame".Here, the configuration of the energy storage device related to the embodiment of the present disclosure and the energy storage device manufactured by the method for manufacturing the energy storage device related to the embodiment of the present disclosure will be described by way of examples. In the explanation of the drawings, the same or similar elements are denoted by the same reference numerals, and description thereof will be omitted.FIG. 1 is a schematic perspective view of the energy storage device. FIG. 2 is an exploded perspective view illustrating a portion of the energy storage device (and includes a partial sectional view). FIG. 3 is a sectional view illustrating a portion of the energy storage device. As illustrated in FIGS. 1 and 3, the energy storage device 4 has an apparatus main body 20 and a laminate film 23 welded to the apparatus main body 20, and it is to be noted that FIGS. 1 and 3 illustrate a state in which the laminate film 23 is welded to a wall portion 12 aof a sealing member 12, and the laminate film 23 is omitted in FIG. 2.The device main body 20 includes an electrode stack 11 serving as a battery, for example, and the sealing member 12 made of resin and sealing the electrode stack 11. The electrode stack 11 is configured by a plurality of electrodes laminated over separators. These electrodes may be constructed, for example, to include a stack of a plurality of bipolar electrodes, a negative end electrode and a positive end electrode.The shape of a battery, for example, the electrode stack 11 is rectangular as viewed from the thickness direction of the battery (i.e., as viewed from the lamination direction of the electrode stack 11). Note that "rectangular" includes not only the case of an exact rectangle (e.g., a rectangle, a square), but also cases where the battery as a whole has a shape resembling a rectangle. Accordingly, the term "rectangular" also includes, for example, shapes that resemble a rectangle and whose corners are slightly rounded. Moreover, the rectangular battery may have a size such that the side lengths of the rectangle have a height of greater than or equal to 1000 mm and a width of greater than or equal to 10,000 mm.The sealing element 12 is formed as a whole in the form of a rectangular tube. The sealing member 12 is disposed on the side surfaces of the electrode stack 11. The sealing member 12 includes a plurality of primary seals 21 and a secondary seal 22 surrounding the primary seals 21 from the outer surfaces along the side surfaces of the electrode stack 11 and connected to the respective primary seals 21. The primary gaskets 21 are, for example, films having a predetermined thickness in the laminating direction.The secondary seal 22 is provided on the outer sides of the electrode stack 11 and the primary seals 21, and structures the outer wall (the case) of the energy storage device 4. The secondary seal 22 is formed in the shape of a rectangular frame extending in the laminating direction in the axial direction. The secondary seal 22 is welded to the outer surfaces of the primary seals 21, for example. From the viewpoint of reducing the manufacturing cost, the secondary seal 22 may be formed at a portion of the outer surfaces of the primary seals 21, e.g., at the portion having injection ports 25.The primary gaskets 21 and the secondary gasket 22 form inner spaces between adjacent electrodes of the electrode stack 11 and seal the inner spaces. Inside the spaces, an electrolyte liquid (not shown) containing, for example, a nonaqueous solvent and an electrolyte salt dissolved in the nonaqueous solvent is housed. The electrolyte liquid is impregnated into, for example, the separators, positive electrodes, and negative electrodes constituting the electrode stack 11.The plurality of injection holes 25 are each provided in the one wall portion 12 athat structures the sealing member 12. The injection ports 25 are respectively communicated with the internal spaces of the various cells.The secondary seal 22 structures the injection port frame surrounding the injection ports 25 on the wall portion 12 a. In the secondary seal 22, a plurality of injection ports 26 are provided, respectively, which communicate with the respective injection ports 25. The electrolyte liquid is injected into the internal spaces through the injection ports 25, 26.At the secondary seal 22, in the regions of the wall portion 12 athat structure the injection port frame, an outer side region 22A corresponding to a first region including the surface contacting the laminate film 23, that is, at the secondary seal 22, an inner side region 22B corresponding to a second region contacting the outer side region 22A and disposed further toward the injection port 26 side than the outer side region 22A including the surface contacting the laminate film 23 is structured by the resin H.The laminate film 23 is welded to the wall surface 22 aof the outer portion 22A at the secondary gasket 22 structuring the injection port frame. By the welding of the laminate film 23 to the wall surface 22 a, the spaces 28 inside the secondary seal 22 communicating with the injection ports 25, 26 are sealed by the laminate film 23. On the laminate film 23, the region corresponding to a third region including the contact surface with the wall portion 12 aof the sub gasket 22 is structured by the resin lam. Note that the secondary gasket 22 is composed of, for example, a metal layer, the resin sheet layer that patterns the one surface of the metal layer that contacts the wall portion 12 a, and a protective resin layer that patterns the other surface of the metal layer, i.e., the surface on the side that does not contact the wall portion 12 a.Further, the respective melting points Tm or glass transition temperatures Tg of the resin L structuring the outer side portion 22A including the wall surface 22 aof the secondary gasket 22, the resin H structuring the inner side portion 22B of the secondary gasket 22, and the resin lam structuring the surface of the laminate film 23 contacting the wall portion 12 aof the secondary gasket 22 satisfy the following conditions a, b and c. a: The melting point Tm or the glass transition temperature Tg of resin L is lower than the melting point Tm or the glass transition temperature Tg of resin H. b: The melting point Tm or the glass transition temperature Tg of resin lam is lower than the melting point Tm or the glass transition temperature Tg of resin H. c: The temperature of the hot pressing is higher than or equal to the melting point Tm or the glass transition temperature Tg of resin L, is higher than or equal to the melting point Tm or the glass transition temperature Tg of resin lam and is lower than the melting point Tm or the glass transition temperature Tg of resin H.As illustrated in FIG. 4, the method for manufacturing the energy storage device related to the embodiment of the present disclosure includes a step of bonding the wall surface 22 aand the laminate film 23 by performing hot pressing from the laminate film s 23 side in a state where the laminate film 23 is caused to contact the wall surface 22 aof the outer portion 22A at the secondary gasket 22 structuring the injection port frame. For example, as shown in FIG. 4, the hot pressing is performed by heating a heating plate member 30, bringing the heating plate member 30 into contact with the laminate film 23, and applying pressure in the direction of arrow A. Since the laminate film 23 is welded to the wall surface 22 aof the secondary gasket 22 structuring the injection port frame, the spaces 28 inside the secondary gasket 22 communicating with the injection ports 25, 26 are sealed by the laminate film 23.The operation and effects of the methods for manufacturing energy storage devices related to the embodiment of the present disclosure will be described herein. According to the energy storage device manufacturing method related to the embodiment of the present disclosure, good tightness of the spaces inside the injection opening frame that communicate with the injection openings can be obtained.First, the case of a conventional energy storage device will be described, namely, a case where the entire injection opening frame is structured by one kind of resin, i.e., a case where the outer side portion (i.e., the portion including the surface contacting the laminate film) and the inner side portion (i.e., the portion contacting the outer side portion and located more toward the injection openings than the outer side portion including the surface contacting the laminate film) are structured by the same resin. When the welding of the laminate film and the injection port frame is performed by hot pressing, the welding is performed at a temperature higher than or equal to the melting points Tm or the glass transition temperatures Tg of the resin structuring the injection port frame and the resin structuring the surface of the laminate film contacting the injection port frame. At this time, the resin of the injection port frame located near the surface contacting the laminate film melts and the flowability thereof increases, and the injection port frame is inserted in the direction in which the pressure is applied by the hot pressing. Thereby, the volume of the spaces sealed by the laminate film inside the injection port frame decreases, and the internal pressure of these spaces increases. When the internal pressure becomes too high, the air contained in the spaces in the injection port frame may break and bulge the molten portions of the resin structuring the injection port frame. For this reason, voids may be formed in the injection port frame at the positions broken by the air in the spaces, and the spaces in the injection port frame may not be sealed.In contrast, in the energy storage device according to the embodiment of the present disclosure, the outer side portion including the surface in contact with the laminate film and the inner side portion in contact with the outer side portion and disposed further toward the injection opening side than the outer side portion including the surface in contact with the laminate film are structured by different resins. The region on the outer side is patterned with resin L, the region on the inner side is patterned with resin H. Moreover, the region on the laminate film including the surface contacting the frame of the injection hole is patterned with resin lam. The melting points Tm or the glass transition temperatures Tg of the resin L structuring the area of the outside and the resin lam structuring the surface of the laminate film contacting the injection port frame are lower than those of the resin H structuring the area of the inside.Namely, the portion of the injection port frame welded to the laminate film (i.e., the portion on the outside) is structured by a resin whose melting point Tm or glass transition temperature Tg is low, and the portion of the injection port frame that is farther toward the battery side than the portion on the outside (i.e., the portion on the inside) is structured by a resin whose melting point Tm or glass transition temperature Tg is high. Further, the portion of the laminate film welded to the injection port frame is structured by a resin whose melting point Tm or glass transition temperature Tg is low. Further, at the time of welding the injection port frame and the laminate film by hot pressing, the temperature of hot pressing is made higher than or equal to the melting points Tm or the glass transition temperatures Tg of the resin L and the resin lam and lower than the melting point Tm or the glass transition temperature Tg of the resin H. Namely, the hot pressing is performed at a temperature at which the outer side portion of the injection hole frame and the portion of the laminate film welded to the injection hole frame melt and at which the inner side portion of the injection hole frame does not melt. Therefore, at the time of welding the injection opening frame and the laminate film to the injection opening frame, only the portion which is the resin whose melting point Tm or glass transition temperature Tg is low (i.e., the outer side portion) will transition to a liquid state, and the portion which is the resin whose melting point Tm or glass transition temperature is high (i.e., the inner side portion) will not enter a liquid state. For this reason, at the time when the injection port frame is inserted in the direction in which the pressure is applied by the hot pressing, excessive insertion of the injection port frame is suppressed. As a result, an increase in the internal pressure of the spaces inside the injection port frame is suppressed, and further, the formation of voids in the injection port frame is suppressed.Thereby, according to the energy storage device manufacturing method related to the embodiment of the present disclosure, good tightness of the spaces inside the injection opening frame that communicate with the injection openings can be obtained.Energy Storage DeviceOperation and effects of the energy storage device related to the embodiment of the present disclosure will be described.According to the energy storage device related to the embodiment of the present disclosure, good tightness of the spaces inside the injection opening frame that communicate with the injection openings can be obtained.In the energy storage device related to the embodiment of the present disclosure, on the injection opening frame, the portion of the outside including the surface in contact with the laminate film and the portion of the inside in contact with the portion of the outside and disposed further toward the injection opening side than the portion of the outside including the surface in contact with the laminate film are structured by different resins. The region on the outer side is patterned with resin L, the region on the inner side is patterned with resin H. In addition, the region on the laminate film including the surface contacting the frame of the injection hole is patterned with resin lam. The melting points Tm or the glass transition temperatures Tg of the resin L structuring the outer side portion and the resin lam structuring the surface of the laminate film contacting the injection port frame are lower than the melting point Tm or the glass transition temperature Tg of the resin H structuring the inner side portion.Namely, the portion of the injection port frame welded to the laminate film (i.e., the portion on the outside) is structured with a resin whose melting point Tm or glass transition temperature Tg is low, and the portion on the injection port frame which is farther toward the battery side than the portion on the outside (i.e., the portion on the inside) is structured with a resin whose melting point Tm or glass transition temperature Tg is high. Further, the portion of the laminate film welded to the injection port frame is structured by a resin whose melting point Tm and glass transition temperature Tg are low, respectively.Therefore, at the time of welding the injection frame and the laminate film, by performing welding at a temperature higher than or equal to the melting points Tm or the glass transition temperatures Tg of the resin L and the resin lam and lower than the melting point Tm or the glass transition temperature Tg of the resin H, the energy storage device having the injection frame in which the formation of voids is suppressed is obtained.Thereby, according to the energy storage device related to the embodiment of the present disclosure, good tightness of the spaces inside the injection opening frame that communicate with the injection openings is obtained.Regarding the structures of the energy storage device related to the embodiment of the present disclosure and the energy storage device manufactured by the method for manufacturing the energy storage device related to the embodiment of the present disclosure, FIGS. 1 to 4 illustrate an embodiment in which the outer side portion 22A on the secondary gasket 22 constituting the injection opening frame is formed by the resin L and all the portions other than the outer side portion 22A are formed by the resin H. However, the structure of the injection port frame of the energy storage device is not limited to this shape. For example, the injection port frame may be structured by three or more kinds of resins. Specifically, for example, the injection opening frame may be configured such that the portion of the outside including the surface in contact with the laminate film is structured by resin L, and the portion of the inside that is in contact with the portion of the outside and is disposed further toward the injection opening side than the portion of the outside including the surface in contact with the laminate film is structured by resin H, and the portion that is disposed further toward the battery side than the portion of the inside of the injection opening frame (i.e., the portion that is disposed further toward the injection opening side than the inside portion and contacts the inside portion but does not contact the outside portion) is structured by resin other than resin L and resin H. However, it is preferable that the energy storage device is configured such that the outer side portion 22A on the injection frame is formed by the resin L and all the portions other than the outer side portion 22A are formed by the resin H.Resin H, Resin L and Resin lamExamples of the resins which are used for the resin H structuring the outer portion of the injection frame, the resin L structuring the inner portion of the injection frame, and the resin lam structuring the surface of the laminate film contacting the injection frame will be described.The combination of, for example, resin H: polypropylene (PP, Tm=15° C.), resin L: polyethylene (PE, Tm=15° C.), and resin lam: PE (Tm=15° C.) is preferable as the combination of resin H, resin L, and resin lam. In this case, in the energy storage device manufacturing method related to the embodiment of the present disclosure, the hot pressing is performed at a temperature of higher than or equal to 130° C. and lower than or equal to 160° C.Further, the following combinations are preferable as resin H, resin L and resin lam.Resin H: modified polyphenylene ether resin (modified PPE resin, Tg=210 °C), Resin L:PE (Tm=130° C.), Resin lam: PE (Tm=130° C.)Resin H: modified PPE resin (Tg=2100° C.), Resin L: PP (Tm=180° C.), Resin lam: PP (Tm=180° C.)Resin H: PP (Tm=180° C.), Resin L: polystyrene (PS, Tm=11° C.), Resin lam: PS (Tm=11° C.)Resin H: PP (Tm=180° C.), Resin L: acrylonitrile-butadiene-styrene copolymer resin (ABS resin, Tm=10° C.), Resin lam: ABS resin (Tm=10° C.)Resin H: modified PPE resin (Tg=21° C.), Resin L: PS (Tm=11° C.), Resin lam: PS (Tm=11° C.)Resin H: modified PPE resin (Tg=2100° C.), Resin L: ABS resin (Tm=10° C.), Resin lam: ABS resin (Tm=10° C.)Note that it is preferable to use, as the resin L and the resin lam, resins whose melting points Tm or glass transition temperatures Tg are the same, and, as the resin H, a resin whose melting point Tm or glass transition temperature Tg is higher than that of the resin L and the resin lam.Molds 1 of Outer Side Portion and Inner Side Portion of Injection Port FrameRegarding the structures of the energy storage device related to the embodiment of the present disclosure and the energy storage device manufactured by the method of manufacturing the energy storage device related to the embodiment of the present disclosure, FIGS. 1 to 4 illustrate a shape in which the contact surfaces of the outer side portion 22A and the inner side portion 22B on the secondary gasket 22 structuring the injection opening frame are planar. However, the structure of the injection port frame of the energy storage device is not limited to this shape.As illustrated in FIG. 5, in a device main body 200 of the energy storage device, it is preferable that the contact surfaces of the outer side portion 220A and the inner side portion 220B on a secondary gasket 220 structuring the injection opening frame are formed convex / concave and have convex / concave portions 220X. Note that the laminate film is omitted in FIG. 5.By forming the contact surfaces of the outer side portion 220A and the inner side portion 220B convex / concave, the contact surface between the outer side portion 220A and the inner side portion 220B can be increased, and the adhesion strength of the outer side portion 220A and the inner side portion 220B can be increased.Here, a method of forming the convex / concave shapes on the contact surfaces of the outer side portion 220A and the inner side portion 220B will be described. First, the inner side portion 220B on the secondary gasket 220 structuring the injection opening frame is molded from resin H (e.g., the inner side portion 220B is molded by injection molding). Next, a surface roughening treatment (e.g., a surface roughening treatment by laser illumination) is performed on the surface of the inner side region 220B to be in contact with the outer side region 220A, and the convex / concave portions 220X are formed on the contact surface of the inner side region 220B. Then, the outer side portion 220A is formed of resin L (e.g., the outer side portion 220A is formed by injection molding) on the contact surface of the inner side portion 220B where the convex / concave portions 220X have been formed. This results in an injection molding frame in which the contact surfaces of the outer portion 220A and the inner portion 220B are formed convex / concave.Molds 2 of Outer Side Portion and Inner Side Portion of Injection Port FrameFurther, it is preferable to design the shapes of the contact surfaces of the outer side portion and the inner side portion of the injection port frame to be locked at the time when the outer side portion is biased toward the side opposite to the injection ports.For example, as illustrated in FIG. 6, a shape in which an outer side portion 222A penetrates an inner side portion 222B and the shapes of the entrance locations 222X are arrow-shaped as viewed from the side surface of the electrode stack 11 is an example of shapes that snap.On an apparatus main body 202 of the energy storage device shown in FIG. 6, portions of the resin L of the outer side portion 222A at a secondary gasket 222 structuring the injection port frame penetrate into the resin H of the inner side portion 222B. The shapes of the locations 222X where the outer side portion 222A penetrates the inner side portion 222B are arrow-shaped as viewed from the side surface of the electrode stack 11. Therefore, the locations 222X on the outer side portion 222A snap into the inner side portion 222B at the moment the outer side portion 222A is biased in the direction (i.e., in the direction of the arrow B) toward the side opposite the injection ports 26. Note that the laminate film is not illustrated in FIG. 6. By making the shape of the outer side portion 222A abut on the inner side portion 222B when the outer side portion 222A is biased toward the side opposite to the injection ports 26, the adhesion strength of the outer side portion 222A and the inner side portion 222B can be increased.Other shapes can be exemplified in which the contact surfaces of the outer side portion and the inner side portion on the injection port frame are shapes that snap at the time when the outer side portion is biased toward the side opposite to the injection ports. For example, as illustrated in FIG. 7, a shape in which an outer side portion 224A penetrates an inner side portion 224B and the shapes of the entrance locations 224X are shaped like the letter T as viewed from the side surface of the electrode stack 11 is an example of the shapes described above that snap. On an apparatus main body 204 of the energy storage device illustrated in FIG. 7, portions of the resin L of the outer side portion 224A at a secondary gasket 224 structuring the injection opening frame penetrate into the resin H of the inner side portion 224B. The shapes of the locations 224X where the outer side portion 224A penetrates the inner side portion 224B are T-shaped as viewed from the side surface of the electrode stack 11. Therefore, the locations 224X on the outer side portion 224A snap into the inner side portion 224B at the time when the outer side portion 224A is biased toward the side opposite to the injection ports 26 in the direction (i.e., in the direction of the arrow B). Note that the laminate film is not illustrated in FIG. 7. By making the shape of the outer side portion 224A abut on the inner side portion 224B when the outer side portion 224A is biased toward the side opposite to the injection ports 26, the adhesion strength of the outer side portion 224A and the inner side portion 224B can be increased.Moreover, as illustrated in FIG. 8, a shape in which an outer side portion 226A penetrates an inner side portion 226B and the shapes of the entrance locations 226X are shaped like the letter L as viewed from the side surface of the electrode stack 11 is another example of the shapes described above that snap. On an apparatus main body 206 of the energy storage device shown in FIG. 8, portions of the resin L of the outer side portion 226A at a secondary gasket 226 structuring the injection port frame penetrate into the resin H of the inner side portion 226B. The shapes of the locations 226X where the outer side portion 226A penetrates the inner side portion 226B are L-shaped as viewed from the side surface of the electrode stack 11. Therefore, the locations 226X latch into the inner side portion 226B at the time when the outer side portion 226A is biased toward the side opposite to the injection ports 26 in the direction (i.e., in the direction of the arrow B). Note that the laminate film is not illustrated in FIG. 8. By making the shape of the outer side portion 226A abut on the inner side portion 226B when the outer side portion 226A is biased toward the side opposite to the injection ports 26, the adhesion strength of the outer side portion 226A and the inner side portion 226B can be increased.Here, a method of forming the injection port frame having a locking shape described above will be described with reference to the shape of FIG. 6 as an example. First, at the time of molding from the resin H, the inner side region 222B is molded on the secondary gasket 222 structuring the injection opening frame, the inner side region 222B molded such that the portions corresponding to the sites 222X are cavities, using a molding method such as injection molding. Next, the outer side portion 222A is molded from the resin L (e.g., the outer side portion 222A is molded by injection molding) to fill the portions that are the voids in the inner side portion 222B (i.e., the portions corresponding to the locations 222X). This results in the injection port frame having the above-described locking shape. Note that injection port frames whose shapes are illustrated in FIGS. 7 and 8 may be similarly formed.Molds 3 of Outer Side Portion and Inner Side Portion of Injection Port FramePreferably, the shapes of the contact surfaces of the outer and inner regions on the frame of the injection opening are designed such that the contact surfaces of the two are large. For example, as illustrated in FIG. 5 described above, a shape configured such that the contacting surfaces of the outside-side portion and the inside-side portion structuring the injection port frame are convex / concave is an example of a shape in which the contacting surfaces of the two are large.As illustrated in FIG. 9, a shape in which an outer side portion 228A penetrates an inner side portion 228B is another example of a shape configured such that the contact areas of the two are large. On an apparatus main body 208 of the energy storage device shown in FIG. 9, portions of the resin L of the outer side portion 228A at a secondary seal 228 structuring the injection port frame penetrate into the resin H of the inner side portion 228B. The shapes of the locations 228X where the outer side portion 228A penetrates the inner side portion 228B are flat plate-shaped as viewed from the side surface of the electrode stack 11. Namely, the outer side portion 228A and the inner side portion 228B contact each other in shapes shaped like nails for piercing. Note that the laminate film is omitted in FIG. 9. By configuring the shapes of the contact surfaces of the outer side portion 228A and the inner side portion 228B in the injection port frame so that the contact surface areas of both are large, the adhesion strength of the outer side portion 228A and the inner side portion 228B can be increased. Note that the injection port frame of the mold formed in FIG. 9 may be formed by a similar method as the injection port frame illustrated in FIG. 6.A battery structuring the energy storage device related to the embodiment of the present disclosure and the energy storage device manufactured by the method for manufacturing the energy storage device related to the embodiment of the present disclosure will be described below.An electrode stack (the electrode stack 11 in FIGS. 1 to 6 ) is an example of a battery. The electrode stack is configured of a plurality of electrodes laminated over separators. The electrodes are laminated, for example, of a plurality of bipolar electrodes.(Positive electrode composite material layer)The positive electrode has a positive electrode composite material layer.The positive electrode composite material layer contains a positive electrode active material and may contain, for example, a binder.Examples of positive electrode active materials are lithium nickel cobalt manganese complex oxides (hereinafter, sometimes referred to simply as "LNCM"). The simplest LNCM is expressed by the general formula LiNi x Co y Mn z O 2 (where x, y, z in the formula are 0<x<1, 0<y<1, 0<z<1, and x+y+z=1). Besides Li, Ni, Co and Mn, LNCM may also contain other elements, for example transition metal elements other than Ni, Co, Mn and main group elements other than Li. LNCM has a layered crystal structure. LNCM accounts for more than 50 mass percent of the total positive electrode active material, and it is good when LNCM is contained in an amount of 80 to 100 mass percent, for example. The positive electrode active material may be structured by LNCM alone. Further, lithium iron phosphate (LiFePO 4, LFP), lithium manganese iron phosphate (LMFP), or the like may be used in the positive electrode active material layer.Examples of other positive electrode active materials are lithium-nickel complex oxides, lithium-cobalt complex oxides and lithium-nickel-manganese complex oxides.Examples of the binders contained in the positive electrode composite material layer are vinyl halide resins such as polyvinylidene fluoride (PVdF).The positive electrode composite material layer may include other components, for example, a conductive material. Examples of the conductive material are hard-graphitizable carbon, easily graphitizable carbon such as carbon black and graphite.(Negative Electrode Composite Material Layer)The electrode has a negative electrode composite material layer.The negative electrode composite material layer contains a negative electrode active material and may contain, for example, a binder.Examples of the negative electrode active material include graphite-based carbons such as natural graphite, artificial graphite, and amorphous coated graphite, metal compounds, elements that can be alloyed with lithium, or compounds thereof, and boron-added carbons. Silicon and tin are examples of elements that can be alloyed with lithium. The graphite content of the graphite-based carbon is greater than or equal to about 50 mass percent, preferably greater than or equal to 80 mass percent. Examples of binders contained in the negative electrode active material are rubbers such as styrene-butadiene copolymer (SBR), and vinyl halide resins such as polyvinylidene fluoride (PVdF).The negative electrode composite material layer may further contain other components such as a thickener. Examples of thickeners are celluloses, for example carboxymethylcellulose (CMC).(Collectors: positive electrode collector and negative electrode collector)In the energy storage device related to the embodiment of the present disclosure, a plurality of bipolar electrodes including, for example, a negative electrode composite material layer on one surface of the collector and a positive electrode composite material layer on the other surface of the collector are laminated over separators. As the collector, conductive members formed of highly conductive metals (e.g., aluminum, stainless steel (SUS), Ni, Cr, Au, Pt, Fe, Ti, and Zn) are suitable.(Separator)The separator is an electrically insulating porous film. The separator electrically isolates the positive electrode and the negative electrode. The separator can have a thickness of 5-30 μm, for example. The separator may be made of, for example, a porous polyethylene (PE) film or a porous polypropylene (PP) film. The separator may have a multilayer structure. For example, the separator may be composed of a PP porous film, a PE porous film, and a PP porous film stacked in this order. The separator may have a heat-resistant layer on its surface. The heat-resistant layer contains a heat-resistant material. Examples of the heat-resistant material are metal oxide particles such as alumina and high melting point resins such as polyimide.(Electrolyte)The energy storage device related to the embodiment of the present disclosure further includes an electrolyte. Electrolyte liquids are examples of the electrolyte, and nonaqueous electrolyte liquids are particularly preferred. A description of the non-aqueous electrolyte liquids will be given below.SolventThe nonaqueous electrolyte liquid contains a solvent (a nonaqueous solvent) and an electrolyte.Examples of the solvent (the nonaqueous solvent) are N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(fluorosulfonyl)imide (DEME), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI), and 1-ethyl-2,3-dimethylimidazolium bis(fluorosulfonyl)imide (DEMI-FSI).Electrolyte ElectrolyteLithium salts are examples of electrolytes in the electrolyte liquid. Examples of lithium salts are lithium bis(fluorosulfonyl)imide (LiFSI), LiPF 6( lithium hexafluorophosphate), lithium tetrafluoroborate (LiF 4) and Li[N(CF 3 SO 2)2].The amount of the electrolyte may be, for example, 1.0-2.0 mol / L, preferably 1.0-1.5 mol / L.In addition to the solvent and electrolyte, the electrolyte liquid may contain various additives, for example, thickeners, film formers and gas generators. The electrolyte is typically a nonaqueous electrolyte liquid that is in a liquid state at normal temperatures (e.g., 25±10° C.). The electrolyte liquid typically assumes a liquid state in battery use environments (e.g., environments with temperatures of -20-+80° C.).(Applications)Examples of the application of the energy storage device related to the embodiment of the present disclosure include the power source of a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), or an electric vehicle (BEV). Explanation of Reference Numerals4 Energy storage device, 11 Electrode stack, 12 Sealing member, 20, 200, 202 Device main body, 21 Primary seal, 22, 220, 222, 224, 226, 228 Secondary seal, 22A, 220A, 222A, 224A, 226A, 228A Outer side region, 22B, 220B, 222B, 224B, 226B, 228B Inner side region, 22a Wall surface, 23 Laminate film, 25, 26 Injection hole, 28 Space, 30 Heater plate member, 220X Convex / Concave portion, 222X, 224X, 226X, 228X SpaceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2020-173921

[0003]

Claims

A method for manufacturing an energy storage device (4) having a battery, injection ports (25, 26) for injecting an electrolyte liquid into the battery, a tubular member (22) surrounding the injection ports (25, 26), and a laminate film (23) welded to the tubular member (22) and sealing spaces (28) inside the tubular member (22) communicating with the injection ports (25, 26), the method comprising: a step of welding the tubular member (22) and the laminate film (23) by bringing the laminate film (23) into contact with the tubular member (22) and performing hot pressing from the laminate film (23) side, wherein a first region (22A) having a surface (22a) contacting the laminate film (23) is performed on the tubular member (22), by resin L, and a second region (22B) which is disposed further toward the injection ports (25, 26) side than the first region (22A) and which contacts the first region (22A) is structured by resin H, and on the laminate film (23), a third region including a surface contacting the laminate film (23) is structured by resin lam, and melting points Tm or glass transition temperatures Tg of the resin L, the resin H and the resin lam are the following conditions a, b and c. a: The melting point Tm or the glass transition temperature Tg of the resin L is lower than the melting point Tm or the glass transition temperature Tg of the resin H. b: The melting point Tm or the glass transition temperature Tg of the resin lam is lower than the melting point Tm or the glass transition temperature Tg of the resin H. c: A temperature of hot pressing is higher than or equal to the melting point Tm or the glass transition temperature Tg of the resin L, is higher than or equal to the melting point Tm or the glass transition temperature Tg of the resin lam, and is lower than the melting point Tm or the glass transition temperature Tg of the resin H.The method for manufacturing an energy storage device (4) according to claim 1, wherein the resin H is polypropylene, and the resin L and the resin lam are polyethylene.The method for manufacturing an energy storage device (4) according to claim 1 or 2, wherein the shape of the battery is rectangular in the thickness direction of the battery, and the side lengths of the rectangle have a height of greater than or equal to 1000 mm and a width of greater than or equal to 10,000 mm.The method for manufacturing an energy storage device (4) according to any one of claims 1 to 3, wherein the tubular member (22) has convex / concave shapes on the surfaces where the second region (22B) and the first region (22A) contact each other.The method for manufacturing an energy storage device (4) according to any one of claims 1 to 3, wherein, on the tubular member (22), surfaces at which the second region (22B) and the first region (22A) contact each other have shapes that snap in at a time when the first region (22A) is strained in a direction toward a side opposite to the injection ports (25, 26).An energy storage device (4) comprising a battery, openings (25, 26) communicating with the inside of the battery, a tubular member (22) surrounding the openings (25, 26), and a laminate film (23) welded to the tubular member (22) and sealing spaces (28) inside the tubular member (22) communicating with the openings (25, 26), wherein on the tubular member (22), a first region (22A) having a surface (22a) contacting the laminate film (23) is structured by resin L, and a second region (22B) disposed further toward the side of the openings (25, 26) than the first region (22A) and contacting the first region (22A) is structured by resin H, On the laminate film (23), a third region having a surface contacting the tubular member (22) is structured by resin lam, and melting points Tm or glass transition temperatures Tg of the resin L, the resin H and the resin lam satisfy the following conditions a and b. a: the melting point Tm or the glass transition temperature Tg of the resin L is lower than the melting point Tm or the glass transition temperature Tg of the resin H. b: the melting point Tm or the glass transition temperature Tg of the resin lam is lower than the melting point Tm or the glass transition temperature Tg of the resin H.The energy storage device (4) according to claim 6, wherein the resin H is polypropylene, and the resin L and the resin lam are polyethylene.The energy storage device (4) according to claim 6 or 7, wherein the shape of the energy storage device (4) is rectangular in the thickness direction of the energy storage device (4), and the side lengths of the rectangle have a height of greater than or equal to 1000 mm and a width of greater than or equal to 10,000 mm.The energy storage device (4) according to any one of claims 6 to 8, wherein the tubular member (22) has convex / concave shapes at the surfaces where the second region (22B) and the first region (22A) contact each other.The energy storage device (4) according to any one of claims 6 to 8, wherein, on the tubular member (22), surfaces at which the second portion (22B) and the first portion (22A) contact each other have shapes that snap at a time when the first portion (22A) is strained in a direction toward a side opposite to the openings (25, 26).

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