Electric power storage module

Abstract

An electric power storage module (10) comprises: a cylindrical electric power storage device (20); a rod-like member (80) provided on a lateral circumferential surface of the electric power storage device (20); a tubular film (90) for packaging the electric power storage device (20) and the rod-like member (80); and an upper holder (41) having an accommodation part (41) that is (a recess) for accommodating the electric power storage device (20). The accommodation part (41) has a groove section (43) into which the rod-like member (80) fits.

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 harsh, and there is a demand for improving the reliability of power storage modules.

[0005] The energy storage module according to the present disclosure comprises a cylindrical energy storage device, a protruding member provided on the side surface of the energy storage device, a cylindrical film that packages the energy storage device and the protruding member, and a holder that has a recessed storage portion and stores the energy storage device in the storage portion, and the storage portion is characterized in that it has a groove portion into which the protruding member fits.

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

[0007] FIG. 4 is an exploded perspective view showing an electricity storage module as an example of an embodiment; FIG. 5 is an axial cross-sectional view showing an electricity storage device; FIG. 6 is an axial cross-sectional view showing a fixing structure of an electricity storage device as an example of an embodiment; FIG. 7 is a cross-sectional view taken along the line AA in FIG. 3; FIG. 8 is a schematic diagram showing a flow of a manufacturing process for an electricity storage module; FIG. 9 is an axial cross-sectional view showing a fixing structure of an electricity storage device as another example of an embodiment; FIG. 10 is an axial cross-sectional view showing a fixing structure of 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 electricity 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 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, rod-shaped members 80 (see Figures 3 and 4) provided on the side surfaces of the energy storage devices 20, and a film 90 (see Figures 3 and 4) that packages the energy storage devices 20 and the rod-shaped members 80.

[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 may have a rectangular tubular shape instead of 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] As shown in FIGS. 3 and 4 , in the energy storage module 10, the energy storage device 20 and the rod-shaped members 80 provided on the side surfaces of the energy storage device 20 are tightly packed in a film 90, and the rod-shaped members 80 are fitted into grooves 43 formed in the upper holder 40 and grooves 53 formed in the lower holder 50, thereby fixing the energy storage device 20 to the upper holder 40 and the lower holder 50. This reduces the need for adhesive and makes it possible to fix the energy storage device 20 to the upper holder 40 and the lower holder 50. This improves the reliability of the energy storage module. However, it is not essential that the energy storage module of the present disclosure does not use any adhesive when fixing the energy storage device. If necessary, adhesive may be interposed between the energy storage device and the holder.

[0020] As described above, the upper holder 40 holds the upper sides of the plurality of power storage devices 20. 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 storage sections 41, which are multiple cylindrical recesses that accommodate the upper sides of the respective power storage devices 20, openings 42 in the ceiling surface of the storage sections 41, and grooves 43 formed along the axial direction on the inner peripheral 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 collecting 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] As described above, the lower holder 50 holds the lower sides of the plurality of power storage devices 20. 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 storage sections 51, which are cylindrical recesses that accommodate the lower sides of the respective power storage devices 20, openings 52 opened on the bottom surfaces of the storage sections 51, and grooves 53 formed along the axial direction on the inner peripheral surface of the storage sections 51. The bottoms of the outer cans 25 of the power storage devices 20 accommodated in the storage sections 51 are exposed from the openings 52. A second current collecting plate 70 is arranged 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] A rod-shaped member 80, an example of a protruding member according to the present disclosure, is provided along the axial direction on the side peripheral surface of the power storage device 20. The rod-shaped member 80 is fixed to the power storage device 20 by being tightly wrapped together with the power storage device 20 in a film 90 (described later). In particular, the rod-shaped member 80 may be interposed between the power storage device 20 and the film 90 in the radial direction of the power storage device 20. The rod-shaped member 80 may be made of resin or metal. If the rod-shaped member 80 is made of metal, it may be connected to, for example, a second current collector plate and serve as a conductive member that collects current from the negative electrode 22. The axial length of the rod-shaped member 80 may be approximately the same as the axial length of the power storage device 20. The cross-sectional shape of the rod-shaped member 80 is preferably circular. This prevents the film 90 from being damaged by the corners of the rod-shaped member 80. The protruding member according to the present disclosure does not necessarily have to be rod-shaped like the rod-shaped member. It may be block-shaped, for example. The surface of the protruding member facing the power storage device may have a recess or a protrusion that conforms to the shape of the outer circumferential surface of the power storage device.

[0026] Film 90 tightly seals and packages power storage device 20 and rod-shaped member 80. Film 90 is cylindrical and seals power storage device 20 and rod-shaped member 80 with the top surface of sealing body 26 of power storage device 20 and the bottom of outer can 25 exposed. Film 90 is a heat-shrinkable film, and is made of, for example, polyolefin, vinyl chloride, silicone rubber, a fluorine-based polymer, a thermoplastic elastomer, or the like.

[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 90 (step S11), a rod-shaped member 80 is placed on the side surface of the energy storage device 20 inserted inside the film 90 (step S12), hot air is blown onto the film 90 to shrink it so that it adheres closely to the energy storage device 20 and the rod-shaped member 80 (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] With the above configuration, the rod-shaped member 80 fits into the groove 43 of the upper holder 40 and the groove 53 of the lower holder 50, thereby restricting circumferential movement of the power storage device 20 in the upper holder 40 and the lower holder 50. This fixes the power storage device 20 to the upper holder 40 and the lower holder 50.

[0029] Conventionally, when recycling energy storage modules, the energy storage device and 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 could reduce the manufacturing efficiency of energy storage modules.

[0030] According to the energy storage module 10 of the present embodiment, it is possible to prevent the use of adhesives and to fix the energy storage device 20 to the upper holder 40 and the lower holder 50. This makes it possible to prevent the reduction in recycling efficiency and manufacturing efficiency that occurs when using the above-mentioned adhesives, and it is possible to improve the recycling efficiency and manufacturing efficiency of the energy storage module 10.

[0031] [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.

[0032] In the energy storage module 100, the energy storage device 20 and a rod-shaped member 81 provided in a spiral shape on the side peripheral surface of the energy storage device 20 are tightly packed in a film 90, and the rod-shaped member 81 is fitted into a groove 53 (not shown) formed in the lower holder 50, thereby fixing the energy storage device 20 to the lower holder 50. This allows the energy storage device 20 and the lower holder 50 to be fixed together.

[0033] The lower holder 50 has a storage portion 51, an opening 52, and a groove portion 53 formed in a spiral shape on the inner circumferential surface of the storage portion 51. The rod-shaped member 81 is formed in a spiral shape and is provided in a spiral shape on the side circumferential surface of the power storage device 20.

[0034] With the above configuration, the rod-shaped members 81 fit into the grooves 53 of the lower holder 50, restricting circumferential movement of the power storage device 20 in the lower holder 50. This allows the power storage device 20 to be fixed to the upper holder 40 without using adhesive.

[0035] A fixing structure of the power storage device 20 of a power storage module 110, which is another example of an embodiment, will be described with reference to Fig. 7. Only the configuration different from the above-described power storage module 10 will be described below, and a description of the configuration similar to the power storage module 10 will be omitted.

[0036] In the energy storage module 110, the energy storage device 20 and rod-shaped members 82 provided on the side peripheral surfaces and bottom surface of the energy storage device 20 are tightly packed in film 90, and the rod-shaped members 82 fit into grooves 43 formed in the upper holder 40 and first grooves 53A and second grooves 53B formed in 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.

[0037] The lower holder 50 has a storage section 51, an opening 52, a first groove section 53A formed along the axial direction on the inner surface of the storage section 51, and a second groove section 53B formed continuously with the first groove section 53A and continuously formed along the radial direction on the inner surface of the storage section 41.

[0038] The rod-shaped member 82 is formed in an L-shape and is provided along the axial direction of the side peripheral surface and the radial direction of the bottom surface of the energy storage device 20. In other words, the rod-shaped member 82 extending in the axial direction along the side peripheral surface of the energy storage device 20 is bent and also extends along the radial direction.

[0039] With the above configuration, the rod-shaped member 82 fits into the groove 43 of the upper holder 40 and the first groove 53A and second groove 53B of the lower holder 50, thereby restricting circumferential movement of the power storage device 20 in the upper holder 40 and the lower holder 50. In this way, the power storage device 20 is fixed to the upper holder 40 and the lower holder 50.

[0040] A fixing structure of the power storage device 20 of a power storage module 120, which is another example of an embodiment, will be described with reference to Fig. 8. Only configurations different from the above-described power storage module 10 will be described below, and a description of configurations similar to the power storage module 10 will be omitted.

[0041] In the energy storage module 120, the energy storage device 20 and rod-shaped members 82 provided along the axial direction on the side peripheral surfaces of the energy storage device 20 are tightly packed in a film 90, and the rod-shaped members 82 are fitted into grooves 43 formed in the upper holder 40 and first grooves 53A and second grooves 53B formed in the lower holder 50, thereby fixing the energy storage device 20 to the upper holder 40 and the lower holder 50. This allows the energy storage device 20 to be fixed to the upper holder 40 and the lower holder 50.

[0042] The lower holder 50 has a storage section 51, an opening 52, a first groove section 53A formed along the axial direction on the inner surface of the storage section 51, and a second groove section 53B formed continuously with the first groove section 53A and formed on the lower surface of the lower holder 50.

[0043] The rod-shaped member 83 is formed in an L-shape, is provided along the axial direction of the side peripheral surface of the power storage device 20 , and extends radially outward from the lower end of the power storage device 20 .

[0044] With the above configuration, the rod-shaped member 82 fits into the first groove 43A and the second groove 43B of the upper holder 40 and the groove 53 of the lower holder 50, thereby restricting circumferential movement of the power storage device 20 in the upper holder 40 and the lower holder 50. In this way, the power storage device 20 is fixed to the upper holder 40 and the lower holder 50.

[0045] Summary The present disclosure is further described by the following embodiments.

[0046] Configuration 1: An energy storage module comprising: a cylindrical energy storage device; a protruding member provided on a side peripheral surface of the energy storage device; a cylindrical film that packages the energy storage device and the protruding member; and a holder that has a recessed accommodation portion and accommodates the energy storage device in the accommodation portion, wherein the accommodation portion has a groove portion that fits over the protruding member.

[0047] 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.

[0048] Configuration 3: The energy storage module according to configuration 1 or 2, wherein the protruding member is provided on the side circumferential surface of the energy storage device along the axial direction of the energy storage device.

[0049] Configuration 4: The energy storage module according to any one of configurations 1 to 3, wherein the protruding member is provided spirally on the side circumferential surface of the energy storage device.

[0050] Configuration 5: The energy storage module according to any one of configurations 1 to 4, wherein the protruding member is bent and provided along a radial direction of the energy storage device.

[0051] Configuration 6: The energy storage module according to any one of configurations 1 to 5, wherein the film is a heat-shrinkable film.

[0052] 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.

[0053] REFERENCE SIGNS LIST 10, 100, 110, 120 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 41 Storage section 42 Opening 43 Groove 43A First groove 43B Second groove 50 Lower holder 51 Storage section 52 Opening 53 Groove 53A First groove 53B Second groove 60 First current collector plate 61 First lead 70 Second current collector plate 71 Second lead 80, 81, 82, 83 Rod-shaped member (protruding member) 90 Film

Claims

1. An energy storage module comprising: a cylindrical energy storage device; a protruding member provided on a side surface of the energy storage device; a tubular film packaging the energy storage device and the protruding member; and a holder having a recessed accommodation portion and accommodating the energy storage device in the accommodation portion, wherein the accommodation portion has a groove portion into which the protruding member fits.

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. An energy storage module according to claim 1, wherein the protruding member is provided on the side peripheral surface of the energy storage device along the axial direction of the energy storage device.

4. An energy storage module according to claim 1, wherein the protruding member is provided in a spiral shape on the side peripheral surface of the energy storage device.

5. An energy storage module according to claim 3, wherein the protruding member is bent and provided along a radial direction of the energy storage device.

6. The energy storage module according to any one of claims 1 to 5, wherein the film is a heat-shrinkable film.

Images