Method for manufacturing power storage device, and power storage device

Abstract

To provide a method for manufacturing a power storage device which can obtain high sealability of a space in a cylindrical member.SOLUTION: A method for manufacturing a power storage device having a battery, a liquid injection port, a cylindrical member surrounding the liquid injection port, and a laminate film includes a step of bringing the laminate film into contact with the cylindrical member, and welding the cylindrical member and the laminate film by hot press, wherein a first region including a surface contacting the laminate film in the cylindrical member is composed of a resin L, a second region which is arranged on a side closer to the liquid injection port side than the first region and contacts the first region is composed of a resin H, a third region including a surface contacting the cylindrical member in the laminate film is composed of a resin lam, the resin L and the resin lam have melting points Tm or glass transition temperatures Tg lower than those of the resin H, and the temperature of the hot press is equal to or higher than the melting point Tm or the glass transition temperature Tg of the resin L and the resin lam, and is less than the melting point Tm or the glass transition temperature Tg of the resin H.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a power storage device and a power storage device.

Background Art

[0002] Conventionally, a power storage device having a battery, a liquid injection port for injecting an electrolyte into the battery, and a cylindrical member surrounding the liquid injection port has been used.

[0003] For example, Patent Document 1 includes a welding step of joining a module body having a seal member and a pressure regulating valve having a case by hot plate welding to integrate them. In the welding step, a hot plate welding device including a hot plate body and a thin plate-shaped cover plate made of a high thermal conductivity rigid body detachably attached to the hot plate body is used. The joining protrusion of the seal member and the joining protrusion of the case are respectively brought into contact with the outer surface of the cover plate. When the joining protrusions are heated and melted by a preset melting amount, the joining protrusions are separated from the outer surface of the cover plate, and then the joining protrusions and the joining protrusions are brought into pressure contact with each other. A method for manufacturing a power storage module is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the conventional method for manufacturing a power storage device, specifically, in the method for manufacturing a power storage device in which the entire cylindrical member surrounding the liquid injection port is made of a kind of resin, when welding the laminate film and the cylindrical member by hot pressing, voids may occur in the cylindrical member. The reason for the occurrence of voids is considered as follows. The resin near the surface of the cylindrical member in contact with the laminate film melts and its fluidity increases due to hot pressing. When the cylindrical member is pushed into the pressurizing direction of the hot press in this state, the internal pressure of the space inside the cylindrical member rises, and when the internal pressure becomes too high, the air in the space breaks through the melted part of the resin constituting the cylindrical member and escapes. As a result, voids may occur in the cylindrical member at the location broken through by the air in the space.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a power storage device capable of obtaining high sealing performance of the space inside the cylindrical member communicating with the liquid injection port, and a power storage device capable of obtaining high sealing performance of the space inside the cylindrical member communicating with the hole leading to the inside of the battery.

Means for Solving the Problems

[0007] The means for solving the above problems includes the following aspects. <1> A method for manufacturing a power storage device having a battery, a liquid injection port for injecting an electrolytic solution into the battery, a cylindrical member surrounding the liquid injection port, and a laminate film welded to the cylindrical member and sealing the space inside the cylindrical member communicating with the liquid injection port, comprising: a step of bringing the laminate film into contact with the cylindrical member and welding the cylindrical member and the laminate film by hot pressing from the laminate film side; a first region including the surface of the cylindrical member in contact with the laminate film is made of resin L, a second region disposed on the liquid injection port side of the first region and in contact with the first region is made of resin H, and a third region including the surface of the laminate film in contact with the cylindrical member is made of resin lam; A method for manufacturing a power storage device, wherein the melting point Tm or glass transition temperature Tg of the resin L, resin H, and resin lam satisfies the following conditions a, b, and c. a: The melting point Tm or glass transition temperature Tg of the resin L is less than the melting point Tm or glass transition temperature Tg of the resin H b: The melting point Tm or glass transition temperature Tg of the resin lam is less than the melting point Tm or glass transition temperature Tg of the resin H c: The temperature of the hot press is equal to or higher than the melting point Tm or glass transition temperature Tg of the resin L, equal to or higher than the melting point Tm or glass transition temperature Tg of the resin lam, and less than the melting point Tm or glass transition temperature Tg of the resin H <2> The method for manufacturing a power storage device according to <1>, wherein the resin H is polypropylene and the resin L and the resin lam are polyethylene. <3> The method for manufacturing a power storage device according to <1> or <2>, wherein the battery has a rectangular shape when viewed in the thickness direction of the battery, and the length of the side in the rectangular shape is 1000 mm or more in the vertical direction and 10000 mm or more in the horizontal direction. <4> The method for manufacturing a power storage device according to any one of <1> to <3>, wherein the cylindrical member has an uneven shape on the surface where the second region and the first region contact. <5> The method for manufacturing a power storage device according to any one of <1> to <3>, wherein the cylindrical member has a shape that catches when the first region is pulled in a direction opposite to the liquid injection port on the surface where the second region and the first region contact. <6> A battery, A hole leading to the inside of the battery, A cylindrical member surrounding the hole, And a laminate film welded to the cylindrical member to seal the space inside the cylindrical member leading to the hole. In the cylindrical member, a first region including a surface in contact with the laminated film is made of resin L, a second region disposed closer to the hole side than the first region and in contact with the first region is made of resin H, and a third region including a surface in contact with the cylindrical member in the laminated film is made of resin lam. A power storage device, wherein the melting point Tm or glass transition temperature Tg of the resin L, resin H, and resin lam satisfies the following conditions a and b. a: The melting point Tm or glass transition temperature Tg of the resin L is less than the melting point Tm or glass transition temperature Tg of the resin H. b: The melting point Tm or glass transition temperature Tg of the resin lam is less than the melting point Tm or glass transition temperature Tg of the resin H. <7> The power storage device according to <6>, wherein the resin H is polypropylene and the resin L and the resin lam are polyethylene. <8> The power storage device according to <6> or <7>, wherein the power storage device has a rectangular shape when viewed in the thickness direction, and the length of the side in the rectangular shape is 1000 mm or more in the vertical direction and 10000 mm or more in the horizontal direction. <9> The power storage device according to any one of <6> to <8>, wherein the cylindrical member has an uneven shape on a surface where the second region and the first region are in contact. <10> The power storage device according to any one of <6> to <8>, wherein the cylindrical member has a shape that catches when the first region is pulled in a direction opposite to the hole on a surface where the second region and the first region are in contact.

Advantages of the Invention

[0008] According to the present disclosure, there are provided a method for manufacturing a power storage device capable of obtaining high sealing performance of a space inside a cylindrical member communicating with a liquid injection port, and a power storage device capable of obtaining high sealing performance of a space inside a cylindrical member communicating with a hole communicating with the inside of a battery.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments which are an example of the present disclosure will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the invention. In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0011] Each component may contain a plurality of corresponding substances. When referring to the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition. The term "process" includes not only independent processes but also those whose intended functions can be achieved even if they cannot be clearly distinguished from other processes.

[0012] <Battery storage device and method for manufacturing the same> A method for manufacturing a battery storage device according to an embodiment of the present disclosure is a method for manufacturing a battery storage device having a battery, a liquid injection port for injecting an electrolytic solution into the battery, a cylindrical member surrounding the liquid injection port, and a laminate film welded to the cylindrical member and sealing a space inside the cylindrical member communicating with the liquid injection port. The method for manufacturing the battery storage device includes a step of welding the cylindrical member and the laminate film by bringing the laminate film into contact with the cylindrical member and performing hot pressing from the laminate film side. A first region including a surface of the cylindrical member in contact with the laminate film is made of resin L, a second region disposed on the liquid injection port side of the first region and in contact with the first region is made of resin H, and a third region including a surface of the laminate film in contact with the cylindrical member is made of resin lam. The melting point Tm or glass transition temperature Tg of resin L, resin H, and resin lam satisfies the following conditions a, b, and c. a: The melting point Tm or glass transition temperature Tg of resin L is less 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 less than the melting point Tm or glass transition temperature Tg of resin H c: The temperature of the hot pressing is equal to or higher than the melting point Tm or glass transition temperature Tg of resin L, equal to or higher than the melting point Tm or glass transition temperature Tg of resin lam, and less than the melting point Tm or glass transition temperature Tg of resin H

[0013] In addition, a battery storage device according to an embodiment of the present disclosure includes a battery, a hole communicating with the inside of the battery, a cylindrical member surrounding the hole, and a laminate film welded to the cylindrical member and sealing a space inside the cylindrical member communicating with the hole. In the cylindrical member, a first region including a surface in contact with the laminate film is made of resin L, a second region disposed closer to the hole side than the first region and in contact with the first region is made of resin H, and a third region including a surface in contact with the cylindrical member in the laminate film is made of resin lam. The melting point Tm or glass transition temperature Tg of resin L, resin H, and resin lam satisfies the conditions of a and b above. The hole is not particularly limited as long as it leads to the inside of the battery, and examples thereof include a liquid injection port. Hereinafter, the "hole" may be simply referred to as the "liquid injection port". Also, the "cylindrical member" may be simply referred to as the "liquid injection port frame".

[0014] Here, a configuration of a power storage device according to an embodiment of the present disclosure and a power storage device manufactured by a manufacturing method of a power storage device according to an embodiment of the present disclosure will be described with an example. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0015] FIG. 1 is a schematic perspective view of a power storage device. FIG. 2 is an exploded perspective view (including a partial cross-sectional view) showing a part of the power storage device. FIG. 3 is a cross-sectional view showing a part of the power storage device. As shown in FIGS. 1 and 3, the power storage device 4 includes a device main body 20 and a laminate film 23 welded to the device main body 20. In FIGS. 1 and 3, a state where the laminate film 23 is welded to the wall portion 12a of the seal member 12 is shown, and the laminate film 23 is omitted in FIG. 2.

[0016] The device main body 20 includes an electrode laminate 11 as an example of a battery and a resin seal member 12 that seals the electrode laminate 11. The electrode laminate 11 is composed of a plurality of electrodes laminated via a separator. These electrodes may have a configuration including, for example, a laminate of a plurality of bipolar electrodes, a negative terminal electrode, and a positive terminal electrode.

[0017] The battery such as the electrode laminate 11 has a rectangular shape when viewed in the thickness direction of the battery (that is, when viewed in the stacking direction in the electrode laminate 11). Here, the "rectangular shape" does not include only the case of an exact rectangle (for example, a rectangle, a square, etc.), but also includes the case where the battery has a shape close to a rectangle as a whole. Therefore, the above "rectangular shape" includes, for example, a shape close to a rectangle with slightly rounded corners. And the rectangular battery can have a size where the length of the side in the rectangular shape is 1000 mm or more in the vertical direction and 10000 mm or more in the horizontal direction.

[0018] The seal member 12 is formed in a rectangular cylindrical shape as a whole. The seal member 12 is disposed on the side surface of the electrode laminate 11. The seal member 12 has a plurality of primary seals 21 and secondary seals 22 that surround the primary seals 21 from the outside along the side surface of the electrode laminate 11 and are coupled to each of the primary seals 21. The primary seal 21 is, for example, a film having a predetermined thickness in the stacking direction.

[0019] The secondary seal 22 is provided outside the electrode laminate 11 and the primary seal 21 and constitutes the outer wall (housing) of the power storage device 4. The secondary seal 22 extends over the entire length of the electrode laminate 11 along the stacking direction. The secondary seal 22 has a rectangular frame shape extending with the stacking direction as the axial direction. The secondary seal 22 is, for example, welded to the outer surface of the primary seal 21. From the viewpoint of reducing manufacturing costs, the secondary seal 22 may be formed on a part of the outer surface of the primary seal 21, for example, on the part having the liquid injection port 25.

[0020] The primary seal 21 and the secondary seal 22 form an internal space between adjacent electrodes in the electrode laminate 11 and seal the internal space. An electrolytic solution (not shown) containing, for example, a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent is accommodated in this internal space. The electrolytic solution is, for example, impregnated in the separator, the positive electrode, and the negative electrode constituting the electrode laminate 11.

[0021] A plurality of liquid injection ports 25 are respectively provided in one wall portion 12a constituting the seal member 12. Each liquid injection port 25 communicates with the internal spaces of different cells respectively.

[0022] The secondary seal 22 constitutes a liquid injection port frame surrounding the liquid injection port 25 in the wall portion 12a. And a plurality of liquid injection ports 26 communicated with each liquid injection port 25 are respectively provided in the secondary seal 22. Electrolyte is injected into the internal space through the liquid injection ports 25 and 26.

[0023] The secondary seal 22 is composed of a resin L in an outer region 22A corresponding to a first region including a surface in contact with the laminate film 23, that is, a wall surface 22a of the secondary seal 22, in a region of the wall portion 12a constituting the liquid injection port frame. Further, the secondary seal 22 has an inner region 22B corresponding to a second region disposed on the liquid injection port 26 side with respect to the outer region 22A including the surface in contact with the laminate film 23 and in contact with the outer region 22A, which is composed of a resin H.

[0024] The laminate film 23 is welded to the wall surface 22a of the outer region 22A of the secondary seal 22 constituting the liquid injection port frame. By welding the laminate film 23 to the wall surface 22a, the space 28 in the secondary seal 22 communicating with the liquid injection ports 25 and 26 is sealed by the laminate film 23. The laminate film 23 has a region corresponding to a third region including the surface in contact with the wall portion 12a of the secondary seal 22 composed of a resin lam. For example, the secondary seal 22 is composed of a metal layer, a resin lam layer constituting a surface on one side of the metal layer and in contact with the wall portion 12a, and a protective resin layer constituting a surface on the other side of the metal layer, that is, a surface not in contact with the wall portion 12a.

[0025] And the melting point Tm or glass transition temperature Tg of each of the resin L constituting the outer region 22A including the wall surface 22a of the secondary seal 22, the resin H constituting the inner region 22B of the secondary seal 22, and the resin lam constituting the surface in contact with the wall portion 12a of the secondary seal 22 in the laminate film 23 satisfies the following conditions a, b, and c. a: The melting point Tm or glass transition temperature Tg of resin L is less 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 less than the melting point Tm or glass transition temperature Tg of resin H c: The temperature of the hot press is equal to or higher than the melting point Tm or glass transition temperature Tg of resin L, equal to or higher than the melting point Tm or glass transition temperature Tg of resin lam, and less than the melting point Tm or glass transition temperature Tg of resin H

[0026] · Method for manufacturing a power storage device As shown in FIG. 4, in the manufacturing method of the power storage device according to the embodiment of the present disclosure, with the laminate film 23 in contact with the wall surface 22a of the outer region 22A in the secondary seal 22 constituting the injection port frame, heat pressing is performed from the laminate film 23 side, thereby welding the wall surface 22a and the laminate film 23. The heat pressing is performed, for example, as shown in FIG. 4, by bringing the hot plate member 30 into contact with the laminate film 23 and heating the hot plate member 30 while applying pressure in the direction of arrow A. By welding the laminate film 23 to the wall surface 22a of the secondary seal 22 constituting the injection port frame, the space 28 in the secondary seal 22 communicating with the injection ports 25 and 26 is sealed by the laminate film 23.

[0027] Here, the actions and effects of the manufacturing method of the power storage device according to the embodiment of the present disclosure will be described. According to the manufacturing method of the power storage device according to the embodiment of the present disclosure, high sealing performance of the space inside the injection port frame communicating with the injection port can be obtained.

[0028] First, regarding a conventional power storage device, specifically when the entire injection port frame is made of a certain resin, in other words, when the outer region (i.e., the region including the surface in contact with the laminate film) and the inner region (i.e., the region disposed closer to the injection port side than the outer region including the surface in contact with the laminate film and in contact with the outer region) are made of the same resin, an explanation will be given. When welding the laminate film and the injection port frame by hot pressing, it is welded at a temperature equal to or higher than the melting point Tm or the glass transition temperature Tg of the resin constituting the injection port frame and the resin constituting the surface of the laminate film in contact with the injection port frame. At this time, the resin near the surface of the injection port frame in contact with the laminate film melts and its fluidity increases, and the injection port frame is pushed in the direction in which pressure is applied by hot pressing. Therefore, the volume of the space sealed by the laminate film inside the injection port frame becomes smaller, and the internal pressure of this space rises. And when the internal pressure rises too much, the air contained in the space inside the injection port frame may break through the melted part of the resin constituting the injection port frame and pop out. As a result, voids are generated in the injection port frame at the location broken through by the air in the space, and the space inside the injection port frame may not be sealed.

[0029] In contrast, in the power storage device according to the embodiment of the present disclosure, the injection port frame is composed of different resins for the outer region including the surface in contact with the laminate film and the inner region disposed closer to the injection port side than the outer region including the surface in contact with the laminate film and in contact with the outer region. That is, the outer region is made of resin L, and the inner region is made of resin H. Also, the region including the surface of the laminate film in contact with the injection port frame is made of resin lam. The resin L constituting the outer region and the resin lam constituting the surface of the laminate film in contact with the injection port frame have a lower melting point Tm or glass transition temperature Tg than the resin H constituting the inner region. That is, the region (i.e., the outer region) where the laminated film in the liquid injection port frame is welded is composed of a resin with a low melting point Tm or glass transition temperature Tg, and the region on the battery side (i.e., the inner region) of the liquid injection port frame is composed of a resin with a high melting point Tm or glass transition temperature Tg than the outer region in the liquid injection port frame. Also, the region where the laminated film is welded to the liquid injection port frame is also composed of a resin with a low melting point Tm or glass transition temperature Tg. When the liquid injection port frame and the laminated film are welded by hot pressing, the temperature of the hot pressing is set to be equal to or higher than the melting point Tm or glass transition temperature Tg of the resin L and the resin lam, and lower than the melting point Tm or glass transition temperature Tg of the resin H. That is, the hot pressing is performed at a temperature at which the outer region in the liquid injection port frame and the region where the laminated film is welded to the liquid injection port frame are melted, and at which the inner region in the liquid injection port frame is not melted. Therefore, when the liquid injection port frame and the laminated film are welded, only the portion of the resin with a low melting point Tm or glass transition temperature Tg (i.e., the outer region) in the liquid injection port frame becomes fluid, and the portion of the resin with a high melting point Tm or glass transition temperature Tg (i.e., the inner region) does not become fluid. As a result, when the liquid injection port frame is pushed in the direction in which pressure is applied by hot pressing, it is suppressed from being pushed in excessively. As a result, an increase in the internal pressure in the space within the liquid injection port frame is suppressed, and the generation of voids in the liquid injection port frame is also suppressed. As described above, according to the method for manufacturing a power storage device according to the embodiment of the present disclosure, high sealing performance of the space within the liquid injection port frame communicating with the liquid injection port can be obtained.

[0030] · Power storage device Also, the operation and effects of the power storage device according to the embodiment of the present disclosure will be described. According to the power storage device according to the embodiment of the present disclosure, high sealing performance of the space within the liquid injection port frame communicating with the liquid injection port can be obtained.

[0031] In the power storage device according to the embodiment of the present disclosure, the injection port frame is composed of different resins for an outer region including a surface in contact with the laminate film and an inner region disposed closer to the injection port side than the outer region including the surface in contact with the laminate film and in contact with the outer region. That is, the outer region is composed of resin L, and the inner region is composed of resin H. Further, a region including a surface in contact with the injection port frame in the laminate film is composed of resin lam. The resin L constituting the outer region and the resin lam constituting the surface in contact with the injection port frame of the laminate film have a lower melting point Tm or glass transition temperature Tg than the resin H constituting the inner region. That is, the region welded to the laminate film in the injection port frame (that is, the outer region) is composed of a resin having a low melting point Tm or glass transition temperature Tg, and the region on the battery side (that is, the inner region) than the outer region in the injection port frame is composed of a resin having a high melting point Tm or glass transition temperature Tg. Further, the region welded to the injection port frame in the laminate film is also composed of a resin having a low melting point Tm or glass transition temperature Tg. Therefore, when welding the injection port frame and the laminate film, by performing the welding at a temperature equal to or higher than the melting point Tm or glass transition temperature Tg of the resin L and the resin lam and lower than the melting point Tm or glass transition temperature Tg of the resin H, a power storage device having an injection port frame with suppressed generation of voids can be obtained. As described above, according to the power storage device according to the embodiment of the present disclosure, high sealing performance of the space inside the injection port frame communicating with the injection port can be obtained.

[0032] Regarding the configuration of the power storage device according to the embodiments of the present disclosure and the power storage device manufactured by the manufacturing method of the power storage device according to the embodiments of the present disclosure, FIGS. 1 to 4 show an aspect in which the outer region 22A of the secondary seal 22 constituting the injection port frame is made of resin L, and all regions other than the outer region 22A are made of resin H. However, the configuration of the injection port frame of the power storage device is not limited to this aspect. For example, the injection port frame may be composed of three or more types of resins. As a specific example, in the injection port frame, the outer region including the surface in contact with the laminate film is made of resin L, the inner region disposed closer to the injection port side than the outer region including the surface in contact with the laminate film and in contact with the outer region is made of resin H, and further, a region on the battery side further than the inner region in the injection port frame (that is, a region disposed closer to the injection port side than the inner region, not in contact with the outer region, and in contact with the inner region) may be made of a resin other than resin L and resin H. However, as shown in FIGS. 1 to 4, it is preferable that the power storage device is in an aspect in which the outer region 22A of the injection port frame is made of resin L and all regions other than the outer region 22A are made of resin H.

[0033] · Resin H, resin L, and resin lam Examples of resins used for resin H that constitutes the outer region of the injection port frame, resin L that constitutes the inner region of the injection port frame, and resin lam that constitutes the surface of the laminate film in contact with the injection port frame will be described. As a combination of resin H, resin L, and resin lam, for example, a combination of resin H: polypropylene (PP, Tm = 160°C), resin L: polyethylene (PE, Tm = 130°C), and resin lam: PE (Tm = 130°C) is preferable. In this case, in the manufacturing method of the power storage device according to the embodiments of the present disclosure, the hot press is performed at a temperature of 130°C or higher and lower than 160°C. Also, the following combinations are also 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 = 210 °C), Resin L: PP (Tm = 160 °C), Resin lam: PP (Tm = 160 °C) · Resin H: PP (Tm = 160 °C), Resin L: Polystyrene (PS, Tm = 110 °C), Resin lam: PS (Tm = 110 °C) · Resin H: PP (Tm = 160 °C), Resin L: Acrylonitrile-butadiene-styrene copolymer resin (ABS resin, Tm = 100 °C), Resin lam: ABS resin (Tm = 100 °C) · Resin H: Modified PPE resin (Tg = 210 °C), Resin L: PS (Tm = 110 °C), Resin lam: PS (Tm = 110 °C) · Resin H: Modified PPE resin (Tg = 210 °C), Resin L: ABS resin (Tm = 100 °C), Resin lam: ABS resin (Tm = 100 °C)

[0034] It is preferable to use resins having the same melting point Tm or glass transition temperature Tg for Resin L and Resin lam, and to use a resin having a melting point Tm or glass transition temperature Tg higher than those of Resin L and Resin lam for Resin H.

[0035] · Shape 1 of the outer region and the inner region in the liquid injection port frame Regarding the configuration of the power storage device according to the embodiment of the present disclosure and the power storage device manufactured by the manufacturing method of the power storage device according to the embodiment of the present disclosure, FIGS. 1 to 4 show an aspect in which the contact surface between the outer region 22A and the inner region 22B of the secondary seal 22 constituting the liquid injection port frame is planar. However, the configuration of the liquid injection port frame of the power storage device is not limited to this aspect.

[0036] As shown in FIG. 5, in the device main body 200 of the power storage device, it is preferable that the contact surface between the outer region 220A and the inner region 220B of the secondary seal 220 constituting the liquid injection port frame has an uneven shape with unevenness 220X. Note that the laminate film is omitted in FIG. 5. Since the contact surface between the outer region 220A and the inner region 220B has an uneven shape, the contact area between the outer region 220A and the inner region 220B increases, and the adhesive strength between the outer region 220A and the inner region 220B can be enhanced.

[0037] Here, a method for forming an uneven shape on the contact surface between the outer region 220A and the inner region 220B will be described. First, the inner region 220B in the secondary seal 220 that constitutes the liquid injection port frame is molded with resin H (for example, the inner region 220B is molded by injection molding). Next, a roughening treatment (for example, roughening treatment by laser irradiation) is performed on the contact surface of the inner region 220B with the outer region 220A to form unevenness 220X on the contact surface of the inner region 220B. Further, by molding the outer region 220A with resin L (for example, molding the outer region 220A by injection molding) on the contact surface of the inner region 220B where the unevenness 220X is formed, a liquid injection port frame in which the contact surface between the outer region 220A and the inner region 220B has an uneven shape can be obtained.

[0038] · Shape of the outer region and the inner region in the liquid injection port frame 2 Also, it is preferable that the shape of the contact surface between the outer region and the inner region in the liquid injection port frame has a shape that catches when the outer region is pulled in the direction opposite to the liquid injection port. As this catching shape, for example, as shown in FIG. 6, the outer region 222A enters the inner region 222B, and the shape of the entered portion 222X is an arrow shape when viewed in the side direction of the electrode laminate 11. In the device body 202 of the power storage device shown in FIG. 6, a part of the resin L of the outer region 222A in the secondary seal 222 that constitutes the liquid injection port frame enters the resin H of the inner region 222B. And the shape of the portion 222X where the outer region 222A enters the inner region 222B is an arrow shape when viewed in the side direction of the electrode laminate 11. Therefore, when the outer region 222A is pulled in the direction opposite to the liquid injection port 26 (that is, the direction of arrow B), the portion 222X catches on the inner region 222B. Note that the laminate film is omitted in FIG. 6. Since the shape of the outer region 222A catches on the inner region 222B when the outer region 222A is pulled in the direction opposite to the liquid injection port 26, the adhesive strength between the outer region 222A and the inner region 222B can be increased.

[0039] Furthermore, as an example of a shape in which the contact surface between the outer region and the inner region in the liquid injection port frame catches when the outer region is pulled in the direction opposite to the liquid injection port, other shapes can be cited. As the above-mentioned catching shape, for example, as shown in FIG. 7, the outer region 224A has entered the inner region 224B, and the shape of the entered portion 224X is in the shape of the letter T in the side view of the electrode laminate 11. In the device main body 204 of the power storage device shown in FIG. 7, a part of the resin L of the outer region 224A in the secondary seal 224 constituting the liquid injection port frame has entered the resin H of the inner region 224B. And the shape of the portion 224X where the outer region 224A has entered the inner region 224B is in the shape of the letter T in the side view of the electrode laminate 11. Therefore, when the outer region 224A is pulled in the direction opposite to the liquid injection port 26 (that is, the direction of arrow B), the portion 224X catches on the inner region 224B. Note that the laminate film is omitted in FIG. 7. Since the shape of the outer region 224A catches on the inner region 224B when the outer region 224A is pulled in the direction opposite to the liquid injection port 26, the adhesion strength between the outer region 224A and the inner region 224B can be increased.

[0040] Furthermore, as another example of the above-mentioned catching shape, as shown in FIG. 8, the outer region 226A has entered the inner region 226B, and the shape of the entered portion 226X is in the shape of the letter L in the side view of the electrode laminate 11. In the device body 206 of the power storage device shown in FIG. 8, a part of the resin L in the outer region 226A of the secondary seal 226 that forms the liquid injection port frame has entered the resin H in the inner region 226B. And the shape of the portion 226X where the outer region 226A has entered the inner region 226B is in the shape of the letter L of the alphabet when viewed in the side direction of the electrode laminate 11. Therefore, when the outer region 226A is pulled in the direction opposite to the liquid injection port 26 (that is, in the direction of arrow B), the portion 226X catches on the inner region 226B. Note that the laminate film is omitted in FIG. 8. Since the shape of the outer region 226A is such that it catches on the inner region 226B when the outer region 226A is pulled in the direction opposite to the liquid injection port 26, the adhesive strength between the outer region 226A and the inner region 226B can be increased.

[0041] Here, a method for forming a liquid injection port frame having the above-described catching shape will be described using the embodiment of FIG. 6 as an example. First, when molding the inner region 222B of the secondary seal 222 that forms the liquid injection port frame with the resin H, for example, by using a molding method such as injection molding, the inner region 222B having a shape in which the portion corresponding to the portion 222X becomes a cavity is molded. Next, by molding the outer region 222A with the resin L so as to fill the cavity portion (that is, the portion corresponding to the portion 222X) in the inner region 222B (for example, molding the outer region 222A by injection molding), a liquid injection port frame having the above-described catching shape can be obtained. Note that the liquid injection port frame can be formed in the same manner for the embodiments shown in FIGS. 7 and 8.

[0042] · Shape of the outer region and the inner region in the liquid injection port frame 3 Also, the shape of the contact surface between the outer region and the inner region in the liquid injection port frame is preferably a shape in which the contact area between the two increases. Examples of the shape in which the contact area between the two increases include a shape in which the contact surface between the outer region and the inner region that form the liquid injection port frame has irregularities as shown in FIG. 5 described above.

[0043] In addition, as another example of the shape in which the contact area between the two increases, as shown in FIG. 9, there is a mode in which the outer region 228A enters the inner region 228B. In the device body 208 of the power storage device shown in FIG. 9, a part of the resin L of the outer region 228A in the secondary seal 228 constituting the liquid injection port frame enters the resin H of the inner region 228B. And the shape of the portion 228X where the outer region 228A enters the inner region 228B is flat when viewed in the side direction of the electrode laminate 11. That is, the outer region 228A and the inner region 228B are in contact with each other in a shape like a nail being stuck. Note that the laminate film is omitted in FIG. 9. Since the shape of the contact surface between the outer region 228A and the inner region 228B in the liquid injection port frame is a shape in which the contact area between the two increases, the adhesion strength between the outer region 228A and the inner region 228B can be increased. Note that the liquid injection port frame in the mode shown in FIG. 9 can also be formed by the same method as the liquid injection port frame shown in FIG. 6.

[0044] Next, the battery that constitutes the power storage device according to the embodiment of the present disclosure and the power storage device manufactured by the manufacturing method of the power storage device according to the embodiment of the present disclosure will be described.

[0045] Examples of the battery include an electrode laminate (the electrode laminate 11 in FIGS. 1 to 6). The electrode laminate is composed of a plurality of electrodes laminated via a separator. The electrode has, for example, a laminate of a plurality of bipolar electrodes.

[0046] (Positive electrode composite material layer) The electrode has a positive electrode composite material layer. The positive electrode composite material layer contains a positive electrode active material and may further contain, for example, a binder. Examples of the positive electrode active material include lithium nickel cobalt manganese composite oxide (hereinafter, may be simply referred to as "LNCM"). The simplest LNCM has the following general formula: LiNi x Co y Mn zIt is represented by O2 (where x, y, and z in the formula satisfy 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1). LNCM may contain, in addition to Li, Ni, Co, and Mn, other additive elements, such as transition metal elements other than Ni, Co, and Mn, and typical metal elements other than Li. LNCM has a layered crystal structure. LNCM may exceed 50% by mass of the entire positive electrode active material, for example, accounting for 80 to 100% by mass. The positive electrode active material may be composed of only LNCM. Also, as the positive electrode active material layer, lithium iron phosphate (LiFePO4, LFP), lithium manganese iron phosphate (LMFP), etc. may be used. Examples of other positive electrode active materials include lithium nickel composite oxides, lithium cobalt composite oxides, lithium nickel manganese composite oxides, etc.

[0047] Examples of the binder contained in the positive electrode composite material layer include vinyl halide resins such as polyvinylidene fluoride (PVdF). The positive electrode composite material layer may further contain other components, such as a conductive material. Examples of the conductive material include graphitized carbon such as hard carbon, easily graphitized carbon such as carbon black, and graphite.

[0048] (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 further contain, for example, a binder. Examples of the negative electrode active material include graphite-based carbon such as natural graphite, artificial graphite, and amorphous-coated graphite, metal compounds, elements or their compounds that can alloy with lithium, and boron-added carbon. Examples of elements that can alloy with lithium include silicon and tin. The proportion of graphite in the graphite-based carbon is generally 50% by mass or more, preferably 80% by mass or more. Examples of the binder contained in the negative electrode active material include rubbers such as styrene-butadiene copolymer (SBR) and vinyl halide resins such as polyvinylidene fluoride (PVdF). The negative electrode composite layer may further contain other components, such as a thickener and the like. Examples of the thickener include celluloses such as carboxymethyl cellulose (CMC).

[0049] (Current collector: positive electrode current collector and negative electrode current collector) The power storage device according to an embodiment of the present disclosure has, for example, a bipolar electrode having a negative electrode composite layer on one surface of a current collector and a positive electrode composite layer on the other surface of the current collector, and a plurality of the bipolar electrodes are laminated via a separator. As the current collector, a conductive member made of a metal having good conductivity (for example, aluminum, stainless steel (SUS), Ni, Cr, Au, Pt, Fe, Ti, and Zn, etc.) is preferable.

[0050] (Separator) The separator is a porous film having electrical insulation. The separator electrically isolates the positive electrode and the negative electrode. The separator may have a thickness of, for example, 5 to 30 μm. The separator can be composed of, for example, a porous polyethylene (PE) film, a porous polypropylene (PP) film, or the like. The separator may have a multilayer structure. For example, the separator may be composed of a porous PP film, a porous PE film, and a porous PP film laminated 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 include metal oxide particles such as alumina and high melting point resins such as polyimide.

[0051] (Electrolyte) The power storage device according to an embodiment of the present disclosure further has an electrolyte. Examples of the electrolyte include an electrolytic solution, and a non-aqueous electrolytic solution is particularly preferable. Hereinafter, the non-aqueous electrolytic solution will be described.

[0052] · Solvent The non-aqueous electrolytic solution contains a solvent (non-aqueous solvent) and an electrolyte. Examples of the solvent (non-aqueous solvent) include N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(fluorosulfonyl)imide (DEME), 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI), 1-ethyl-2,3-dimethylimidazolium bis(fluorosulfonyl)imide (DEMI-FSI), and the like.

[0053] · Electrolyte Examples of the electrolyte in the electrolyte solution include Li salts. Examples of the Li salts include lithium bis(fluorosulfonyl)imide (LiFSI), LiPF6 (lithium hexafluorophosphate), lithium tetrafluoroborate (LiBF4), Li[N(CF3SO2)2], and the like. The amount of the electrolyte may be, for example, 1.0 to 2.0 mol / L, and preferably 1.0 to 1.5 mol / L.

[0054] In addition to the solvent and the electrolyte, the electrolyte solution may contain various additives, such as a thickener, a film-forming agent, a gas-generating agent, and the like. The electrolyte is typically a non-aqueous electrolyte solution that is liquid at room temperature (for example, 25 ± 10 °C). The electrolyte solution typically exhibits a liquid state under the use environment of the battery (for example, in a temperature environment of -20 to +60 °C).

[0055] (Use) Examples of the use of the power storage device according to the embodiment of the present disclosure include power sources for hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), battery electric vehicles (BEVs), and the like.

Explanation of Reference Numerals

[0056] 4 Battery device, 11 Electrode laminate, 12 Seal member, 20, 200, 202 Device body, 21 Primary seal, 22, 220, 222, 224, 226, 228 Secondary seal, 22A, 220A, 222A, 224A, 226A, 228A Outer region, 22B, 220B, 222B, 224B, 226B, 228B Inner region, 22a Wall surface, 23 Laminate film, 25, 26 Liquid injection port, 28 Space, 30 Hot plate member, 220X Concavity and convexity, 222X, 224X, 226X, 228X Location

Claims

1. A method for manufacturing an electric storage device, comprising: a battery; a liquid injection port for injecting an electrolytic solution into the battery; a cylindrical member surrounding the liquid injection port; and a laminate film welded to the cylindrical member and sealing a space inside the cylindrical member communicating with the liquid injection port, the method including a step of welding the cylindrical member and the laminate film by bringing the laminate film into contact with the cylindrical member and performing hot pressing from the laminate film side, wherein a first region including a surface of the cylindrical member in contact with the laminate film is made of resin L, a second region disposed on the liquid injection port side of the first region and in contact with the first region is made of resin H, and a third region including a surface of the laminate film in contact with the cylindrical member is made of resin lam, and a melting point Tm or glass transition temperature Tg of the resin L, resin H, and resin lam satisfies the following conditions a, b, and c. a: The melting point Tm or glass transition temperature Tg of the resin L is less than the melting point Tm or glass transition temperature Tg of the resin H. b: The melting point Tm or glass transition temperature Tg of the resin lam is less than the melting point Tm or glass transition temperature Tg of the resin H. c: The temperature of the hot pressing is equal to or higher than the melting point Tm or glass transition temperature Tg of the resin L, equal to or higher than the melting point Tm or glass transition temperature Tg of the resin lam, and less than the melting point Tm or glass transition temperature Tg of the resin H.

2. The method for manufacturing an electric storage device according to claim 1, wherein the resin H is polypropylene, and the resin L and the resin lam are polyethylene.

3. The method for manufacturing an electric storage device according to claim 1, wherein the battery has a rectangular shape when viewed in the thickness direction of the battery, and a length of a side of the rectangle is 1000 mm or more in the vertical direction and 10000 mm or more in the horizontal direction.

4. The method for manufacturing an electric storage device according to claim 1, wherein the cylindrical member has an uneven shape on a surface where the second region and the first region are in contact.

5. The method for manufacturing an electric storage device according to claim 1, wherein the shape of a surface where the second region and the first region are in contact of the cylindrical member has a shape that catches when the first region is pulled in a direction opposite to the liquid injection port.

6. An electric storage device, comprising: a battery; a hole communicating with the inside of the battery; a cylindrical member surrounding the hole; and a laminate film welded to the cylindrical member and sealing a space inside the cylindrical member communicating with the hole. In the cylindrical member, a first region including a surface in contact with the laminate film is made of resin L, a second region disposed closer to the hole side than the first region and in contact with the first region is made of resin H, and a third region including a surface in contact with the cylindrical member in the laminate film is made of resin lam. The power storage device, wherein the melting point Tm or glass transition temperature Tg of the resin L, resin H, and resin lam satisfies the following conditions a and b. a: The melting point Tm or glass transition temperature Tg of the resin L is lower than the melting point Tm or glass transition temperature Tg of the resin H. b: The melting point Tm or glass transition temperature Tg of the resin lam is lower than the melting point Tm or glass transition temperature Tg of the resin H.

7. The power storage device according to claim 6, wherein the resin H is polypropylene, and the resin L and the resin lam are polyethylene.

8. The power storage device according to claim 6, wherein the power storage device has a rectangular shape when viewed in the thickness direction, and the length of the sides of the rectangle is 1000 mm or more in the vertical direction and 10000 mm or more in the horizontal direction.

9. The power storage device according to claim 6, wherein the cylindrical member has an uneven shape on the surface where the second region and the first region are in contact.

10. The power storage device according to claim 6, wherein the shape of the surface where the second region and the first region are in contact of the cylindrical member has a shape that catches when the first region is pulled in a direction opposite to the hole.

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