Electric power storage module

Abstract

An electric power storage module (10) comprises: an electric power storage device (20) having a first end surface positioned at one end in the axial direction, and a second end surface positioned at the other end opposite from the one end along the axial direction; a holder (50) that accommodates the electric power storage device (20); and a pressing member (80) that is provided on the first end surface of the electric power storage device (20) and is fixed to the holder (50) in a state in which the electric power storage device (20) is pressed toward the second end surface. The holder (50) has an accommodation part (51) that is a recess for accommodating the electric power storage device (20), and an opening (52) that is a through-hole communicating with one end of the accommodation part (50). The electric power storage device (20) is accommodated in the accommodation part (50), and the pressing member (80) is accommodated in the opening (52).

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] The environments in which energy storage modules are used are becoming increasingly harsh, and there is a demand for further improvements in the reliability of energy storage modules.

[0005] The energy storage module according to the present disclosure comprises an energy storage device having a first end face located at one axial end of an axial module and a second end face located at the other end opposite the one end along the axial direction, a holder for accommodating the energy storage device, and a pressing member provided on the first end face of the energy storage device and fixed to the holder in a state pressing the energy storage device toward the second end face, wherein the holder has a storage portion which is a recess and an opening which is a through hole communicating with one end of the storage portion, and the energy storage device is accommodated in the storage portion and the pressing member is accommodated in the opening.

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

[0007] Fig. 1 is an exploded perspective view showing an electricity storage module as an example of an embodiment; Fig. 2 is an axial cross-sectional view showing an electricity storage device; Fig. 3 is an axial cross-sectional view showing a fixing structure for an electricity storage device as an example of an embodiment; Fig. 4 is an axial cross-sectional view showing a fixing structure for an electricity storage device as another example of an embodiment; Fig. 5 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 first direction, the vertical direction, or the height direction. The vertical direction may also be referred to as the upper side or the lower side. Furthermore, the radial direction or the circumferential direction of the cylindrical energy storage device 20 may also be referred to.

[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 as a second holder 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, and a pressing member 80 (see Figure 3) that presses 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 configured on the top surface of the sealing body 26, and the negative electrode terminal may be configured 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 FIG. 3 .

[0019] In the energy storage module 10, the pressing member 80 is screwed into the lower holder 50 and fixed to the lower holder 50 while pressing the energy storage device 20 upward, so that the energy storage device 20 is sandwiched axially between the pressing member 80 and the upper holder 40. This reduces the need for adhesive and allows the energy storage device 20 to be fixed to the upper holder 40 and the lower holder 50. This improves the reliability of the energy storage module 10. 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] 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 to the ceiling surface of the storage sections 41. From the viewpoint of securing the power storage devices 20, the inner diameter of the openings may be smaller than the outer diameter of the power storage devices 20. 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] 3 , the first current collector 60 is a conductive member that collects current from the positive electrodes 21 of the multiple power storage devices 20. 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 upper 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. Furthermore, when the power storage devices 20 are connected in series within the power storage module 10, the first current collector 60 may be connected to the negative electrode 22 of another power storage device 20.

[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 accommodation sections 51, which are cylindrical recesses that accommodate the lower sides of the respective power storage devices 20, and female thread sections 52 (openings) into which the pressing members 80, described below, are threaded. The female thread sections 52 are formed on the inner circumferential surface of the openings that axially penetrate the accommodation sections 51. 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 together by a fixing means. For example, the fixing means may be such that a bolt is inserted into a hole that passes through the upper holder 40 and the lower holder 50, and the upper holder 40 and the lower holder 50 are fixed together by fastening the bolt and a nut. Although the holder of the present embodiment is divided into the upper holder 40 and the lower holder 50, the holder of the present disclosure is not limited to this. For example, the upper holder 40 and the lower holder 50 may be integrated into one holder.

[0024] In FIG. 3 , the second current collector 70 is a conductive member that collects current from the negative electrodes 22 of the multiple energy storage devices 20. A second lead 71 is formed on the second current collector 70 and connected to the bottom surface of the outer can 25, which serves as the negative terminal of the energy storage device 20. The second lead 71 is formed in an upwardly convex shape and is connected to the bottom surface of the outer can 25 exposed through an opening 82 of a pressing member 80 fixed to the lower holder 50. Therefore, the opening 82 overlaps with one axial end surface of the energy storage device 20. However, the second current collector of the present disclosure is not limited thereto. For example, if a shoulder portion of the outer can 25 of the energy storage device 20 serves as the negative terminal, the second current collector 70 may be disposed on the upper surface of the upper holder 40. Furthermore, when the energy storage devices 20 are connected in series within the energy storage module 10, the second current collector 70 may be connected to the positive electrode 21 of another energy storage device 20.

[0025] As described above, the pressing member 80 is provided below the power storage device 20 and presses the power storage device 20 upward. However, the pressing member of the present disclosure is not limited to this and may be provided above the power storage device 20 and presses the power storage device 20 downward. The pressing member 80 is made of the same material as the lower holder 50 and the upper holder 40, for example, a thermoplastic resin. The pressing member 80 is fixed to the lower holder 50 by being screwed onto the lower holder 50 from below.

[0026] The pressing member 80 is formed in a substantially cylindrical shape. The pressing member 80 has a male thread portion 81 formed on the side circumferential surface and threadedly engaged with the female thread portion 52 of the lower holder 50, and an opening 82 penetrating in the axial direction. The opening 82 exposes the bottom surface of the outer can 25 of the power storage device 20 housed in the housing portion 51. However, the pressing member of the present disclosure is not limited thereto. For example, if the second current collecting plate 70 is disposed on the upper surface of the upper holder 40, the opening 82 does not need to be formed. The power storage device 20 pressed in the axial direction by the pressing member 80 is sandwiched and fixed together with the pressing member 80 at a portion of the upper holder 40 adjacent to the opening 42. Furthermore, by providing a pressing member 80 for each housing portion 51, it is possible to perform pressing with the pressing member 80 in accordance with the size of each power storage device 20.

[0027] In the manufacturing process of the energy storage module 10, for example, the energy storage device 20 is accommodated in the accommodation portion 41 of the upper holder 40, the energy storage device 20 is accommodated in the accommodation portion 51 of the lower holder 50 (the lower holder 50 is assembled to the upper holder 40), the upper holder 40 and the lower holder 50 are fixed by a fixing means, the pressing member 80 is screwed into the lower holder 50, the energy storage device 20 is pressed upward by the pressing member 80, the energy storage device 20 is pressed against the accommodation portion 41 of the upper holder 40, and the energy storage device 20 is sandwiched and fixed between the pressing member 80 and the upper holder 40. In this way, the energy storage device 20 is fixed to the upper holder 40 and the lower holder 50.

[0028] 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.

[0029] According to the energy storage module 10 of the present embodiment, the use of adhesive is reduced and the energy storage device 20 can be fixed to the upper holder 40 and the lower holder 50. This makes it possible to suppress the reduction in recycling efficiency and manufacturing efficiency that occurs when using the above-mentioned adhesive, and improves the recycling efficiency and manufacturing efficiency of the energy storage module 10.

[0030] [Fixing Structure of Energy Storage Device According to Another Embodiment] A fixing structure of the energy storage device 20 in an energy storage module 90, which is another example of an embodiment, will be described using Fig. 4. Only configurations that differ from the above-described energy storage module 10 will be described below, and a description of configurations that are the same as those in the energy storage module 10 will be omitted.

[0031] In the electricity storage module 90, the pressing member 80 is screwed into the lower holder 50 and fixed to the lower holder 50 while pressing the electricity storage device 20 upward, whereby the electricity storage device 20 is sandwiched axially between the pressing member 80 and the upper holder 40. Furthermore, the electricity storage device 20 is pressed radially by the ring member 91 sandwiched between the upper holder 40 and the lower holder 50. This allows the electricity storage device 20 to be fixed to the upper holder 40 and the lower holder 50.

[0032] The upper holder 40 has a storage portion 41, an opening 42, and a stepped portion 43 into which the ring member 91 is fitted. The stepped portion 43 is formed in an annular shape along the circumferential direction of the storage portion 41 at the edge of the storage portion 41 on the bottom surface of the upper holder 40.

[0033] The lower holder 50 has a storage portion 51, a female screw portion 52, and a stepped portion 53 into which the ring member 91 is fitted. The stepped portion 53 is formed in an annular shape along the circumferential direction of the storage portion 51 at the edge of the storage portion 51 on the upper surface of the lower holder 50.

[0034] In the energy storage module 90 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 energy storage module of the present disclosure is not limited to this. For example, the step portion may be formed only in the upper holder 40, or only in the lower holder 50, or the upper holder 40 and the lower holder 50 may not have a step portion.

[0035] The ring member 91 is formed in an annular shape. The ring member 91 is preferably made of an elastic material, such as rubber, urethane, sponge, or the like. The cross-sectional shape of the ring member 91 perpendicular to the circumferential direction (hereinafter simply referred to as the cross-sectional shape) is rectangular. However, the cross-sectional shape of the ring member of the present disclosure is not limited to this and may be circular. The cross-sectional shape of the ring member 91 is preferably slightly larger than the cross-sectional shape of the space formed by the step portion 43 of the upper holder 40 and the step portion 53 of the lower holder 50.

[0036] In the manufacturing process of the energy storage module 10, for example, the energy storage device 20 is accommodated in the accommodation portion 41 of the upper holder 40, and the energy storage device 20 is accommodated in the accommodation 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 together by a fixing means. At this time, the ring member 91 is compressed and deformed, and the ring member 91 protrudes radially inward, thereby pressing the energy storage device 20 in the radial direction. In addition, friction at the interface between the ring member 91 and the energy storage device 20 can further suppress displacement of the energy storage device 20 in the axial direction.

[0037] Furthermore, pressing member 80 is screwed into lower holder 50, and power storage device 20 is pressed upward by pressing member 80, power storage device 20 is pressed against housing portion 41 of upper holder 40, and power storage device 20 is sandwiched and fixed between pressing member 80 and upper holder 40. In this way, power storage device 20 is fixed to upper holder 40 and lower holder 50.

[0038] A fixing structure of the energy storage device 20 in the energy storage module 100, which is another example of the embodiment, will be described with reference to Fig. 5. 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.

[0039] In the energy storage module 100, the pressing member 110 is press-fitted into the lower holder 50 and fixed to the lower holder 50 while pressing the energy storage device 20 upward, whereby the energy storage device 20 is sandwiched in the axial direction between the pressing member 80 and the upper holder 40. This allows the energy storage device 20 to be fixed to the upper holder 40 and the lower holder 50.

[0040] The lower holder 50 has an accommodation portion 51 and an opening 54 into which a pressing member 110 (described later) is press-fitted. The opening 54 is formed so as to increase in diameter downward. The upper surface of the pressing member 110 may have a recess, and the axial end of the power storage device 20 may be accommodated in the recess.

[0041] As described above, the pressing member 110 is provided below the power storage device 20 and is press-fitted into the lower holder 50 to fix the power storage device 20 in a state where it presses upward. The outer diameter of the pressing member 110 is formed to increase in diameter as it extends downward. The pressing member 110 is formed in a substantially cylindrical shape. The pressing member 110 is formed to have a radial length slightly longer than the radial length of the opening 54 of the lower holder 50. The pressing member 110 has an opening 111 penetrating in the axial direction. The pressing member 110 may also be made of an elastic material. A cylindrical body having higher rigidity than the elastic material may be provided in the opening 54 of the pressing member 110 made of an elastic material such as rubber. A leaf spring portion may also be provided on the outer peripheral surface of the pressing member 110. Furthermore, a protrusion may be formed on the outer surface of the leaf spring portion and fitted into a recess provided in the inner peripheral surface of the opening 54 of the lower holder 50 to fix the lower holder 50 and the pressing member 110.

[0042] In the manufacturing process of the energy storage module 100, for example, the energy storage device 20 is accommodated in the accommodation portion 41 of the upper holder 40, the energy storage device 20 is accommodated in the accommodation portion 51 of the lower holder 50 (the lower holder 50 is assembled to the upper holder 40), the upper holder 40 and the lower holder 50 are fixed by a fixing means, the pressing member 110 is press-fitted into the lower holder 50, the energy storage device 20 is pressed upward by the pressing member 80, the energy storage device 20 is pressed against the accommodation portion 41 of the upper holder 40, and the energy storage device 20 is sandwiched and fixed between the pressing member 110 and the upper holder 40. In this way, the energy storage device 20 is fixed to the upper holder 40 and the lower holder 50.

[0043] Summary The present disclosure is further described by the following embodiments.

[0044] Configuration 1: An energy storage module comprising: an energy storage device having a first end face located at one axial end of the energy storage device and a second end face located at the other axial end opposite the first end; a holder that houses the energy storage device; and a pressing member that is provided at the first end face of the energy storage device and is fixed to the holder in a state where it presses the energy storage device towards the second end face, wherein the holder has a storage portion that is a recess and an opening that is a through hole that communicates with one end of the storage portion, wherein the energy storage device is housed in the storage portion and the pressing member is housed in the opening.

[0045] Configuration 2: The 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.

[0046] Configuration 3: The energy storage module according to configuration 1 or 2, wherein the pressing member is fixed to the holder by being screwed thereto.

[0047] Configuration 4: The energy storage module according to any one of configurations 1 to 3, wherein the holder includes a first holder and a second holder, and the first holder and the second holder are aligned along the axial direction of the energy storage device.

[0048] Configuration 5: The energy storage module according to any one of configurations 1 to 4, further comprising an elastic member provided around the energy storage device and between the first holder and the second holder.

[0049] Configuration 6: The energy storage module according to any one of configurations 1 to 5, wherein the pressing member is press-fitted and fixed into the opening of the holder.

[0050] Configuration 7: The energy storage module according to any one of configurations 1 to 6, further comprising a conductive member electrically connected to the energy storage device, wherein the pressing member is made of an insulating material and has an opening that is a through hole extending along the axial direction, wherein the opening of the pressing member and the first end surface of the energy storage device overlap when viewed in the axial direction, and the conductive member is inserted into the opening of the pressing member and electrically connected to the energy storage device.

[0051] Configuration 8: The energy storage module according to any one of configurations 1 to 7, wherein the energy storage device includes: an electrode group including a first electrode and a second electrode; an outer can that houses the electrode group and has an opening at one end in the first direction; and a sealing body that closes the opening of the outer can, and the outer can has a cylindrical outer circumferential surface.

[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, 90, 100 Energy storage module 20 Energy storage device 21 Positive electrode (first electrode) 22 Negative electrode (second 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 Female screw portion (opening) 53 Step portion 54 Opening 60 First current collector plate 61 First lead 70 Second current collector plate 71 Second lead 80, 110 Pressing member 81 Male screw portion (opening) 82 Opening 91 Ring member (elastic member)

Claims

1. An energy storage module comprising: an energy storage device having a first end face located at one axial end of the energy storage module and a second end face located at the other end opposite the first end along the axial direction; a holder for accommodating the energy storage device; and a pressing member provided on the first end face of the energy storage device and fixed to the holder in a state pressing the energy storage device towards the second end face, wherein the holder has a accommodating portion which is a recess, and an opening which is a through hole communicating with one end of the accommodating portion, wherein the energy storage device is accommodated in the accommodating portion and the pressing member is accommodated in the opening.

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 or 2, wherein the pressing member is screwed and fixed to the holder.

4. An energy storage module according to claim 3, wherein the holder includes a first holder and a second holder, and the first holder and the second holder are aligned along the axial direction of the energy storage device.

5. An energy storage module according to claim 4, further comprising an elastic member provided around the energy storage device and between the first holder and the second holder.

6. An energy storage module according to claim 1 or 2, wherein the pressing member is fixed by being pressed into the opening of the holder.

7. An energy storage module as claimed in claim 1 or 2, further comprising a conductive member electrically connected to the energy storage device, the pressing member being made of an insulating material, the pressing member having an opening which is a through hole extending along the axial direction, the opening of the pressing member and the first end face of the energy storage device overlapping when viewed in the axial direction, and the conductive member being inserted into the opening of the pressing member and electrically connected to the energy storage device.

8. A storage module according to claim 1 or 2, wherein the storage device includes: an electrode group including a first electrode and a second electrode; an outer can housing the electrode group and having an opening at one end in the first direction; and a sealing body closing the opening of the outer can, and the outer peripheral surface of the outer can is cylindrical.

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