Power storage module

Abstract

The present invention comprises: a power storage device (20); a film (80) that packages an outer peripheral surface of the power storage device (20); and a holder that has a housing part constituting a recess and that houses the power storage device (20) in the housing part. The film (80) has a fold part (80A) that protrudes outward from the outer peripheral surface side of the power storage device (20). The holder includes an upper holder (40) and a lower holder (50). The upper holder (40) and the lower holder (50) are aligned along the axial direction of the power storage device (20). The fold part (80A) is sandwiched between the upper holder (40) and the lower holder (50).

Description

Energy storage module

[0001] The present disclosure relates to an energy storage module.

[0002] The power storage module is used as a power source equipped with a plurality of power storage devices. In the power storage module, the power storage devices are housed in a holder. In the power storage module disclosed in Patent Document 1, the power storage devices are fixed to the holder with an adhesive.

[0003] JP 2012-009389 A

[0004] In recent years, the environments in which power storage modules are used have become increasingly severe, and there is a demand for improving the reliability of power storage modules.

[0005] The energy storage module according to the present disclosure comprises an energy storage device, a film that wraps the outer peripheral surface of the energy storage device, and a holder that has a recessed storage section and stores the energy storage device in the storage section, wherein the film has a wrinkled section that protrudes outward from the outer peripheral surface side of the energy storage device, the holder includes a first holder and a second holder, the first holder and the second holder are aligned along the axial direction of the energy storage device and are divided into, and the wrinkled section is sandwiched between the first holder and the second holder.

[0006] According to the energy storage module of the present disclosure, reliability can be improved.

[0007] Fig. 3 is an exploded perspective view showing an electricity storage module as an example of an embodiment; Fig. 4 is an axial cross-sectional view showing an electricity storage device; Fig. 5 is an axial cross-sectional view showing a fixing structure for an electricity storage device as an example of an embodiment; Fig. 6 is a cross-sectional view taken along line AA in Fig. 3; Fig. 7 is a schematic diagram showing the flow of a manufacturing process for an electricity storage module; Fig. 8 is an axial cross-sectional view showing a fixing structure for an electricity storage device as another example of an embodiment;

[0008] An example of an embodiment of the present disclosure will be described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc. are examples for facilitating understanding of the present disclosure, and can be appropriately changed according to the application, purpose, specifications, etc.

[0009] [Electricity Storage Module] An electric power storage module 10 as an example of an embodiment will be described with reference to FIG.

[0010] The power storage module 10 is mounted on an electric vehicle as a power source for the motor that drives the electric vehicle. However, the power storage module of the present disclosure is not limited to being mounted on an electric vehicle, and may be used as a power source for motor-driven electric devices such as power tools, power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. Furthermore, the use of the power storage module of the present disclosure is not limited, and may be used as a power source for various electric devices used indoors and outdoors, such as vacuum cleaners, radios, lighting devices, digital cameras, and video cameras.

[0011] In the following description of the energy storage module 10, the axial direction of a cylindrical energy storage device 20 (described later) may be referred to as the up-down direction. Also, the up-down direction may be referred to as the upper side or the lower side. Furthermore, the description may be referred to as the radial direction or the circumferential direction of the cylindrical energy storage device 20.

[0012] The energy storage module 10 comprises a plurality of energy storage devices 20, an upper holder 40 as a first holder that holds the upper sides of the energy storage devices 20, a lower holder 50 that holds the lower sides of the energy storage devices 20, a first current collecting plate 60 arranged on the upper surface of the upper holder 40, a second current collecting plate 70 arranged on the bottom surface of the lower holder 50 as a second holder, and a film 80 (see Figure 3) that packages the energy storage devices 20.

[0013] The multiple power storage devices 20 may be packed as densely as possible within the power storage module 10 while taking safety into consideration, and adjacent power storage devices 20 may be arranged substantially close to each other. For example, the power storage devices 20 may be arranged such that six power storage devices 20 surround one power storage device 20 in a plan view (or arranged in a staggered pattern). Alternatively, the multiple power storage devices may be arranged such that the power storage devices closest to each other are located on all four sides.

[0014] [Power Storage Device] The power storage device 20 as an example of an embodiment will be described in detail with reference to FIG.

[0015] In this embodiment, a cylindrical lithium-ion secondary battery is used as the power storage device 20, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 20 includes an electrode group 24, for example, a band-shaped positive electrode 21 and a band-shaped negative electrode 22 wound together with a band-shaped separator 23 interposed therebetween; a cylindrical outer can 25 that houses the electrode group 24 together with an electrolyte; a sealing member 26 that insulates and seals an opening provided at one axial end of the outer can 25; a foil-shaped positive electrode tab 27 that electrically connects the positive electrode 21 to the sealing member 26; and a negative electrode tab 28 that electrically connects the negative electrode 22 to the outer can 25. An insulating gasket 29 may be disposed between the outer periphery of the sealing member 26 and the inner circumferential surface of the opening of the outer can 25. Note that the positive electrode 21 may be electrically connected to the outer can 25, and the negative electrode 22 may be electrically connected to the outer can 25. The outer can 25 may have a rectangular tubular shape rather than a cylindrical shape.

[0016] An annular groove 25A is formed on the outer peripheral surface of the outer can 25, on the opening side. This groove 25A is formed as an annular protrusion on the inner peripheral surface of the outer can 25. The gasket 29 and sealing body 26 are disposed on this annular protrusion within the outer can 25. Furthermore, the opening end of the outer can 25 is crimped so as to bend toward the inside of the outer can 25, with the gasket 29 disposed on the inner peripheral side. The crimped opening end and the protrusion sandwich the sealing body 26 in the axial direction via the gasket 29, thereby sealing the opening of the outer can 25.

[0017] The sealing body 26 may be provided with a current interrupter (CID) or an exhaust valve that ruptures when the pressure inside the outer can 25 reaches or exceeds a predetermined pressure. Furthermore, an insulating plate 30 for insulating the electrode group 24 from the outer can 25 may be provided between the electrode group 24 and the bottom of the outer can 25 or between the electrode group 24 and the protrusion (groove 25A). When the insulating plate 30 is provided, the positive electrode tab 27 may extend through a through-hole formed in the insulating plate 30. The negative electrode tab 28 may extend through a through-hole formed in the insulating plate 30 or may extend around the insulating plate 30. In the energy storage device 20, as described above, the positive electrode terminal may be provided in the sealing body 26, and the negative electrode terminal may be provided on the bottom surface of the outer can 25.

[0018] [Fixing Structure of the Power Storage Device] A fixing structure of the power storage device 20 in the power storage module 10, which is one example of an embodiment, will be described with reference to FIGS. 3 to 5. FIG.

[0019] 3 and 4 , in the energy storage module 10, the energy storage device 20 is tightly wrapped in the film 80, and the wrinkled portion 80A of the film 80 is sandwiched between the upper holder 40 and the lower holder 50, thereby fixing the energy storage device 20 to the upper holder 40 and the lower holder 50. This makes it possible to fix the energy storage device 20 to the upper holder 40 and the lower holder 50 without using adhesive. However, it is not an essential requirement of the energy storage module of the present invention that no adhesive be used at all when fixing the energy storage device. If necessary, adhesive may be interposed between the energy storage device and the holder.

[0020] The upper holder 40, which serves as a first holder, holds the upper sides of the plurality of power storage devices 20, as described above. The upper holder 40 is formed, for example, from a thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and examples of such resins include polyethylene, polypropylene, polyamide, and ABS. The upper holder 40 has a plurality of storage sections 41, which are cylindrical depressions that accommodate the upper sides of the respective power storage devices 20, and openings 42 that open in the ceiling surface of the storage sections 41. The top surfaces of the sealing bodies 26 of the power storage devices 20 accommodated in the storage sections 41 are exposed through the openings 42. A first current collector plate 60 is disposed on the upper surface of the upper holder 40.

[0021] The first current collector 60 is a conductive member that collects current from the positive electrodes 21 of the multiple power storage devices 20 in the power storage module 10. The first current collector 60 has a first lead 61 formed thereon that is connected to the top surface of the sealing body 26 that serves as the positive electrode terminal of the power storage device 20. The first lead 61 is formed in a rectangular shape, inclined downward from the top surface of the upper holder 40, and connected to the top surface of the sealing body 26 through the opening 42 of the upper holder 40.

[0022] The lower holder 50 serving as the second holder holds the lower sides of the plurality of power storage devices 20 as described above. The lower holder 50 is formed of the same material as the upper holder 40, for example, a thermoplastic resin. The lower holder 50 has a plurality of housing sections 51 in which the lower sides of the respective power storage devices 20 are housed, and openings 52 opened on the bottom surfaces of the housing sections 51. The bottoms of the outer casings 25 of the power storage devices 20 housed in the housing sections 51 are exposed from the openings 52. A second current collecting plate 70 is disposed on the bottom surface of the lower holder 50.

[0023] The upper holder 40 and the lower holder 50 are fixed to each other by a fixing means, such as a bolt that is inserted into a hole that passes through the upper holder 40 and the lower holder 50, and then the upper holder 40 and the lower holder 50 are fixed to each other by fastening the bolt and a nut.

[0024] The second current collector 70 is a conductive member that collects current from the negative electrodes 22 of the multiple power storage devices 20 in the power storage module 10. A second lead 71 is formed on the second current collector 70 and is connected to the bottom surface of the exterior can 25 that serves as the negative terminal of the power storage device 20. The second lead 71 is formed in an upwardly convex shape and is connected to the bottom surface of the exterior can 25 that is exposed from the opening 52 of the lower holder 50. However, the second current collector of the present disclosure is not limited to this, and may be disposed on the upper surface of the upper holder 40, for example, in the case where the shoulder of the exterior can 25 of the power storage device 20 serves as the negative terminal.

[0025] Film 80 wraps the outer peripheral surface of power storage device 20. Film 80 is cylindrical and wraps power storage device 20 with the top surface of sealing body 26 of power storage device 20 and the bottom of outer can 25 exposed. Film 80 is a heat-shrinkable film and is made of, for example, polyolefin, vinyl chloride, silicone rubber, fluorine-based polymer, thermoplastic elastomer, or the like. Film 80 has a wrinkled portion 80A that is sandwiched between the lower surface of upper holder 40 and the upper surface of lower holder 50.

[0026] The wrinkled portion 80A is formed at the boundary between the upper holder 40 and the lower holder 50 in the axial direction, protruding radially outward along the circumferential direction. The wrinkled portion 80A is formed by folding the film 80. To more stably secure the power storage device 20, the wrinkled portion 80A may be formed around the entire circumferential direction. To suppress bias in the circumferential direction of the securing force, it is preferable that the radial length (protruding length) of the wrinkled portion 80A be the same around the entire circumferential direction. Note that the film 80 may be formed with multiple wrinkled portions in the axial direction, and these multiple wrinkled portions may be bundled and clamped between the holders for securing. Furthermore, the wrinkled portion of the present disclosure does not need to extend straight in the radial direction of the power storage device, but may extend at an angle relative to the radial direction. In other words, it is sufficient that the wrinkled portion protrudes outward toward the outer circumferential surface of the power storage device.

[0027] As shown in FIG. 5 , in the manufacturing process of the energy storage module 10, for example, the energy storage device 20 is inserted inside a cylindrical film 80 (step S11), the film 80 and, for example, the lower side of the energy storage device 20 are inserted into a jig 90 described later and hot air is blown onto them to form wrinkled portions 80A (step S12), the hot air is blown onto the film 80 to shrink the film 80 so that it adheres closely to the energy storage device 20 (step S13), the energy storage device 20 is accommodated in the accommodating portion 41 of the upper holder 40, and the energy storage device 20 is accommodated in the accommodating portion 51 of the lower holder 50 (the lower holder 50 is assembled to the upper holder 40), and the upper holder 40 and the lower holder 50 are fixed by a fixing means.

[0028] Jig 90 is formed in a cylindrical shape with an inner diameter smaller than the inner diameter of the original form of film 80. One end face of jig 90 is formed with wrinkle-creating portion 90A that slopes downward from the inside to the outside. With jig 90, wrinkles 80A can be formed in wrinkle-creating portion 90A by inserting film 80 and the lower side of electricity storage device 20, for example, into jig 90 and applying hot air, and because wrinkle-creating portion 90A is sloped, film 80 can be smoothly removed from the shrunk film.

[0029] With the above configuration, wrinkled portion 80A of film 80 is sandwiched between the lower surface of upper holder 40 and the upper surface of lower holder 50, restricting circumferential movement of power storage device 20 in upper holder 40 and lower holder 50. In this way, power storage device 20 is fixed to upper holder 40 and lower holder 50.

[0030] Conventionally, when recycling energy storage modules, the energy storage device and the holder were fixed together with an adhesive, making it impossible to separate the energy storage device (metal material) from the holder (resin material). In other words, the use of adhesive reduced the recycling efficiency of energy storage modules. Furthermore, in the manufacturing process of energy storage modules, the adhesive application process had large quality variations, making quality control time-consuming. Furthermore, a drying process was required to dry the adhesive. In other words, the use of adhesive reduced the manufacturing efficiency of energy storage modules.

[0031] According to the energy storage module 10 of this embodiment, it is possible to fix the energy storage device 20 to the upper holder 40 and the lower holder 50 without using adhesive. This makes it possible to suppress the reduction in recycling efficiency and manufacturing efficiency that occurs when using the adhesive, and improves the recycling efficiency and manufacturing efficiency of the energy storage module 10. This improves the reliability of the energy storage module 10.

[0032] [Fixing Structure of Energy Storage Device of Another Embodiment] A fixing structure of the energy storage device 20 of the energy storage module 100, which is another example of the embodiment, will be described using Fig. 6. Only the configuration different from the above-described energy storage module 10 will be described below, and a description of the configuration similar to the energy storage module 10 will be omitted.

[0033] In the energy storage module 100, the energy storage device 20 is tightly packed in the film 80, and the wrinkled portion 80A of the film 80 is sandwiched between the step portion 43 of the upper holder 40 and the step portion 53 of the lower holder 50, thereby fixing the energy storage device 20 to the upper holder 40 and the lower holder 50. This makes it possible to fix the energy storage device 20 to the upper holder 40 and the lower holder 50 without using adhesive.

[0034] Upper holder 40 has a storage section 41, an opening 42, and a step section 43 that engages with wrinkled section 80A of film 80. Step section 43 is formed in an annular shape along the circumferential direction of storage section 41 at the edge of storage section 41 on the top surface of upper holder 40.

[0035] Lower holder 50 has a storage portion 51, an opening 52, and a step portion 53 that engages with wrinkled portion 80A of film 80. Step portion 53 is formed in an annular shape along the circumferential direction of storage portion 51 at the edge of storage portion 51 on the lower surface of lower holder 50.

[0036] With the above configuration, wrinkled portion 80A of film 80 is sandwiched between step portion 43 of upper holder 40 and step portion 53 of lower holder 50, restricting circumferential movement of power storage device 20 in upper holder 40 and lower holder 50. This allows power storage device 20 to be fixed to upper holder 40 and lower holder 50 without using adhesive.

[0037] In the energy storage module 100 of the present embodiment, the step portion 43 is formed in the upper holder 40 and the step portion 53 is formed in the lower holder 50, but the present disclosure is not limited to this. For example, the step portion 43 may be formed only in the upper holder 40, or the step portion 53 may be formed only in the lower holder 50.

[0038] Furthermore, the inner surface of the stepped portion of the present disclosure may have a protrusion formed thereon in a region facing the wrinkled portion, protruding toward the wrinkled portion. This protrusion may be formed to extend continuously in the circumferential direction of the stepped portion, or may be arranged intermittently. When the wrinkled portion is accommodated in the stepped portion, the protrusion preferentially contacts the wrinkled portion at the stepped portion, thereby generating a stronger holding force. Therefore, the protrusion may face the wrinkled portion in the axial direction and protrude in the axial direction.

[0039] Summary The present disclosure is further described by the following embodiments.

[0040] Configuration 1: An energy storage module comprising: an electric storage device; a film that wraps an outer peripheral surface of the electric storage device; and a holder that has a recessed storage portion and stores the electric storage device in the storage portion, wherein the film has a wrinkled portion that protrudes outward from the outer peripheral surface side of the electric storage device, the holder includes a first holder and a second holder, the first holder and the second holder are aligned along the axial direction of the electric storage device, and the wrinkled portion is sandwiched between the first holder and the second holder.

[0041] Configuration 2: The energy storage module according to configuration 1, comprising a plurality of energy storage devices, each of the plurality of energy storage devices being the energy storage device, and the plurality of energy storage devices being housed in the holder.

[0042] Configuration 3: The energy storage module according to configuration 1 or 2, wherein the corrugated portion is annular along an outer circumferential surface of the energy storage device.

[0043] Configuration 4: The energy storage module according to any one of configurations 1 to 3, wherein the corrugated portion is located at or near the axial center of the energy storage device. Note that "near there" means "near the axial center of the energy storage device." As long as the effect of the present application can be obtained, the corrugated portion does not need to be located strictly at the axial center of the energy storage device. As long as the corrugated portion is located near the axial center of the energy storage device, substantially the same effect can be obtained.

[0044] Configuration 5: The energy storage module according to any one of configurations 1 to 4, wherein the first holder and / or the second holder has a step portion with which the corrugated portion engages.

[0045] Configuration 6: The energy storage module according to any one of configurations 1 to 5, wherein the inner surface of the step portion of the first holder and / or the second holder has a protrusion extending toward the wrinkled portion in a region facing the wrinkled portion.

[0046] Configuration 7: The energy storage module according to any one of configurations 1 to 6, wherein the film is a heat-shrinkable film.

[0047] Configuration 8: The energy storage module of any one of configurations 1 to 7, wherein the energy storage device is cylindrical.

[0048] It should be noted that the present disclosure is not limited to the above-described embodiments and their variations, and it goes without saying that various modifications and improvements are possible within the scope of the matters described in the claims of the present application.

[0049] REFERENCE SIGNS LIST 10, 100 Energy storage module 20 Energy storage device 21 Positive electrode 22 Negative electrode 23 Separator 24 Electrode group 25 Outer can 25A Groove 26 Sealing body 27 Positive electrode tab 28 Negative electrode tab 29 Gasket 30 Insulating plate 40 Upper holder (first holder) 41 Storage portion 42 Opening 43 Step portion 50 Lower holder (second holder) 51 Storage portion 52 Opening 53 Step portion 60 First current collector plate 61 First lead 70 Second current collector plate 71 Second lead 80 Film 80A Wrinkled portion 90 Jig 90A Wrinkled portion (Wrinkled portion)

Claims

1. An energy storage module comprising: an energy storage device; a film that wraps an outer peripheral surface of the energy storage device; and a holder having a recessed storage portion that houses the energy storage device in the storage portion, wherein the film has a wrinkled portion that protrudes outward from the outer peripheral surface side of the energy storage device, the holder includes a first holder and a second holder, the first holder and the second holder are aligned along the axial direction of the energy storage device, and the wrinkled portion is sandwiched between the first holder and the second holder.

2. An energy storage module according to claim 1, comprising a plurality of energy storage devices, each of the plurality of energy storage devices being the energy storage device, and the plurality of energy storage devices being housed in the holder.

3. The energy storage module according to claim 1, wherein the corrugated portion is annular along the outer circumferential surface of the energy storage device.

4. The energy storage module according to claim 3, wherein the corrugated portion is located at or near the center of the energy storage device in the axial direction.

5. The energy storage module according to claim 4, wherein the first holder and / or the second holder has a step portion with which the wrinkled portion engages.

6. An energy storage module according to claim 5, wherein the first holder and / or the second holder has a protrusion on the inner surface of the step portion in a region facing the wrinkled portion, the protrusion extending toward the wrinkled portion.

7. The energy storage module according to any one of claims 1 to 6, wherein the film is a heat-shrinkable film.

8. The energy storage module according to any one of claims 1 to 6, wherein the energy storage device is cylindrical.

Images