Energy storage module

Abstract

This power storage module comprises: at least one cylindrical power storage device; and a cell holder for housing the power storage device. The cell holder includes: a holding section that holds an axial-direction lower side of the power storage device; and a side wall section that covers a lateral circumferential surface of the power storage device. The holding section includes: a housing part that houses a lower end of the storage device; and a notch formed along an inner surface of the housing section on a side surface of the holding section.

Description

Technical Field

[0001] The present disclosure relates to a power storage module.

Background Art

[0002] A power storage module is known as a power source including a plurality of power storage devices housed in its housing portion (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an impact is applied to the power storage module from the outside, a large load acts on the power storage device, the power storage device is greatly deformed, and the safety of the power storage module may be impaired. With reference to FIG. 6, a cell holder 130 for mounting a conventional power storage module 110 will be described. FIG. 6 is a perspective view and a partially enlarged view showing the cell holder 130 of the power storage module 110.

[0005] The power storage module 110 includes a plurality of cylindrical power storage devices (not shown) and a cell holder 130 that houses the plurality of power storage devices. The cell holder 130 has a holding portion 140 that holds the lower side in the axial direction of the power storage device and a side wall portion 150 that covers the side surface in the axial direction of the power storage device. The holding portion 140 has a housing portion 141 that houses the lower end side of the power storage device.

[0006] If the energy storage module 110 is subjected to an impact and the cell holder 130 is crushed, the holding part 140 will be damaged, and a triangular piece 147 will be formed on the outer edge of the holding part 140, separating from the holding part 140. If the triangular piece 147 pierces the side surface of the energy storage device, the energy storage device may be damaged, causing a short circuit and thermal runaway. As a result, the safety of the energy storage module 10 may be reduced if the energy storage module 110 is subjected to an impact and the cell holder 30 is crushed.

[0007] The purpose of this disclosure is to provide an energy storage module that can improve safety. [Means for solving the problem]

[0008] An energy storage module according to one aspect of the present disclosure comprises at least one cylindrical energy storage device and a cell holder housing the energy storage device, the cell holder having a holding portion for holding one axial side of the energy storage device and a side wall portion covering the side of the energy storage device, the holding portion having at least one housing portion for housing one end or the other end of the energy storage device and a first notch formed on the side of the holding portion along the inner surface of the housing portion. [Effects of the Invention]

[0009] According to one aspect of this disclosure, the safety of the energy storage module can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing an energy storage module according to an embodiment. [Figure 2] This is a perspective view and a partially enlarged view showing a cell holder, which is an example of an embodiment. [Figure 3] This is a plan view and a partially enlarged view showing a holding part, which is an example of an embodiment. [Figure 4] This is a cross-sectional view AA in Figure 3. [Figure 5] This is a plan view and a partially enlarged view showing a cell holder, which is another example of an embodiment. [Figure 6] These are perspective views and partially enlarged views showing the cell holder of a conventional energy storage module. [Modes for carrying out the invention]

[0011] Embodiments of this disclosure will be described below with reference to the drawings. The shapes, materials, and quantities described below are illustrative and can be appropriately changed according to the specifications of the energy storage module.

[0012] The energy storage module 10 according to the embodiment will be described with reference to Figure 1. Figure 1 is a perspective view showing the energy storage module 10. In the following description, the side on which the cover 60 that closes the cell holder 30 is provided will be referred to as the upper side in terms of the axial direction of the energy storage device 20.

[0013] The energy storage module 10 is primarily used as a power source. For example, the energy storage module 10 is used as a power source for motor-driven electric equipment such as electric vehicles, power tools, electric assist bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the applications of the energy storage module 10 are not limited, and it may also be used as a power source for various electrical devices used indoors and outdoors, such as cleaners, radios, lighting devices, digital cameras, and video cameras.

[0014] In Figure 1, the energy storage module 10 comprises a plurality of cylindrical energy storage devices 20, a cell holder 30 that houses the plurality of energy storage devices 20, and a lid 60 that covers the top surface of the cell holder 30. Details of the cell holder 30 will be described later in the explanation of Figure 2 and beyond.

[0015] In this example, the power storage device 20 uses a cylindrical lithium-ion secondary battery, but it may also be a nickel-metal hydride battery, a capacitor, or the like. The power storage device 20 includes, for example, an electrode group in which a strip-shaped positive electrode and a strip-shaped negative electrode are wound with a strip-shaped separator interposed therebetween, a cylindrical exterior can that houses the electrode group together with an electrolytic solution, a sealing body that seals the opening of the exterior can in an insulated state, a foil-shaped positive electrode lead that electrically connects the positive electrode and the sealing body, and a negative electrode lead that electrically connects the negative electrode and the exterior can. An insulating gasket may be disposed between the outer periphery of the sealing body and the inner peripheral surface of the opening of the exterior can.

[0016] An annular groove portion is formed on the outer peripheral surface of the exterior can on the opening side. This groove portion is formed as an annular protrusion on the inner peripheral surface of the exterior can. The gasket and the sealing body are disposed on this annular protrusion inside the exterior can. Further, the opening end of the exterior can is caulked so as to fall inward of the exterior can with a gasket disposed on the inner peripheral side. The sealing body is sandwiched in the vertical direction via the gasket by the caulked opening end and the convex portion, whereby the opening of the exterior can is sealed.

[0017] The sealing body may be provided with a current interruption mechanism (CID) or an exhaust valve that ruptures when the pressure inside the exterior can reaches a predetermined pressure or higher. Further, an insulating plate for insulating the electrode group and the exterior can may be provided between the electrode group and the holding portion of the exterior can or between the electrode group and the convex portion (groove portion). When the insulating plate is provided, the positive electrode lead may extend through a through-hole formed in the insulating plate. The negative electrode lead may extend through a through-hole formed in the insulating plate or may extend around the insulating plate.

[0018] In the power storage device 20, a positive electrode terminal is formed on the top surface of the sealing body, and a negative electrode terminal is disposed toward the upper end portion (caulked opening end) of the exterior can. Note that the electrode group may be connected such that the exterior can functions as a positive electrode terminal and the sealing body functions as a negative electrode terminal.

[0019] The plurality of power storage devices 20 are densely filled in the power storage module 10 considering safety, and adjacent power storage devices 20 may be arranged in close proximity to each other. In the power storage device 20, for example, in a plan view, six power storage devices 20 are arranged to surround one power storage device 20 (hereinafter, a staggered arrangement). In addition, the plurality of power storage devices 20 may be connected in series or in parallel via a conductive current collecting plate (not shown). At this time, the position where the lead extending from the current collecting plate is connected to the power storage device may be the top surface of the sealing body as the positive electrode terminal and the open end of the caulked exterior can as the negative electrode terminal.

[0020] The lid 60 closes the upper surface of the cell holder 30 as described above. An exhaust duct communicating with the exhaust valve of the power storage device 20 may be provided below the lid 60. The exhaust duct may communicate with an exhaust port provided in the cell holder 30. The lid 60 has a plurality of holes so that the sealing bodies of the plurality of power storage devices 20 are exposed. Through these plurality of holes, the upper end side portion (the top surface of the sealing plate) of the power storage device 20 and the current collecting member may be electrically connected. Further, the lid 60 may be provided with a plurality of holes for exposing the opening of the exterior can. The opening of the exterior can and the current collecting member may be electrically connected through these plurality of holes.

[0021] Using FIG. 2, the cell holder 30 which is an example of an embodiment will be described in detail. FIG. 2 is a perspective view and a partially enlarged view showing the cell holder 30.

[0022] The cell holder 30 has a holding portion 40 that holds the lower axial side of the energy storage device 20 and a side wall portion 50 that covers the axially extending side surface of the energy storage device 20. With the cell holder 30, if an impact is applied from the side of the energy storage module 10, the energy storage device 20 can be protected from the impact. The cell holder 30 may also have a configuration in which the holding portion 40 holds the upper axial portion of the energy storage device 20 and a side wall portion 50 that covers the axial side surface of the energy storage device 20. In this case, when the cell holder 30 is viewed from above, the side wall portion 50 may be positioned away from the housing portion 41 such that there is a predetermined distance between the housing portion 41 closest to the side wall portion 50 and the side wall portion 50. This configuration makes it possible to interpose a filler material such as an insulating resin between the side wall portion 50 and the housing portion 41. This allows the energy storage device 20 to be fixed more firmly within the cell holder 30. In this configuration, the filler material connects the lower end of the side wall portion 50 to the opening edge of the housing portion 41 closest to the side wall portion 50, and also has a surface that extends radially across the energy storage device 20. This filler material may be interposed not only in the gap between the housing portion 41 and the side wall portion 50, but also in the gaps between adjacent housing portions 41 and the gap between the housing portion 41 and the energy storage device 20.

[0023] The holding portion 40 is formed on the bottom surface of the cell holder 30 and holds the lower axial side of the energy storage devices 20 when they are arranged. This allows the energy storage devices 20 to be housed in the cell holder 30 in their arranged state. The holding portion 40 has a plurality of housing portions 41 which are recesses that house the lower end of the energy storage devices 20, and a notch 42 which is a first notch formed along the housing portions 41 on the outer surface (edge) of the holding portion 40.

[0024] Each of the multiple housing sections 41 is fitted with the lower end portion of the energy storage device 20. As a result, the lower end portion of the energy storage device 20 is held in the holding section 40 of the cell holder 30. The housing section 41 includes a bottom surface section 43 facing the lower end surface (bottom surface) of the energy storage device 20, a wall section 44 having an annular inner surface facing the side surface of the lower end of the energy storage device 20, and an opening 45 formed in the bottom surface section 43 that exposes the bottom surface of the energy storage device 20.

[0025] As described above, the notch 42 is formed along the housing portion 41 on the side surface of the holding portion 40 of the cell holder 30. The notch 42 is formed between adjacent housing portions 41 at the edge of the holding portion 40. In plan view, the notch 42 is formed to be a roughly triangular recess having an arc along the inner circumferential surface of the housing portion 41.

[0026] In other words, the notch 42 is formed by cutting out the side surface of the holding portion 40 such that the thickness of the outer wall portion 44 of at least one of the housing portions 41 closest to the edge of the holding portion 40 is a predetermined thickness. The predetermined thickness is preferably the minimum thickness that can ensure the rigidity of the cell holder 30, but it is not limited to this minimum thickness. Furthermore, this notch 42 may also be formed in the housing portion 41 closest to the corner of the holding portion 40. In addition, a recess may be formed in the region surrounded by multiple housing portions 41 on the lower end surface (axial end surface) of the holding portion 40. Of the inner surface of this recess, the surface facing the wall portion 44 of the housing portion 41 surrounding this recess may be formed along the inner surface of the wall portion 44. A recess with the above inner surface can obtain the same effect as the notch 42.

[0027] The notch 42 may be formed in a substantially triangular shape with a straight section along the housing section 41 in a plan view. Alternatively, a wall portion may be formed in the notch 42 along the outer circumferential surface of the holding section 40.

[0028] The notch 42 allows for the thinning of the triangular piece 47 formed near the side surface of the holding part 40 (the edge of the holding part 40) when the cell holder 30 is crushed due to an impact on the energy storage module 10.

[0029] By thinning the triangular piece 47, its rigidity is weakened (made more fragile), and even if the triangular piece 47 comes into contact with the side surface of the energy storage device 20, damage to the energy storage device 20 can be suppressed. This prevents the energy storage device 20 from short-circuiting and leading to thermal runaway. As a result, the safety of the energy storage module 10 can be improved in the event that the cell holder 30 is crushed due to an impact on the energy storage module 10.

[0030] As described above, the side wall portion 50 covers the side circumferential surface of the energy storage device 20. Of the side wall portion 50, the side wall portion 50 that covers the longitudinal direction in a plan view of the energy storage module 10 has a notch 52 as a second cutout formed along the side circumferential surface of the energy storage device 20.

[0031] The notch 52 is formed in the region below the approximate center in the axial direction of the side wall portion 50. The notch 52 is formed between adjacent energy storage devices 20 at the edge of the cell holder 30. In plan view, the notch 52 is formed in a roughly triangular shape with an arc along the energy storage device 20.

[0032] In other words, the notch 42 is formed by cutting out the outer side of the side wall 50 so that the thickness of the side wall portion 50 becomes a predetermined thickness. The predetermined thickness should be any thickness that ensures the rigidity of the cell holder 30.

[0033] The notch 52 allows for the thinning of the triangular piece 53 formed by the damage to the side wall portion 50 when the energy storage module 10 is subjected to impact and the cell holder 30 is crushed.

[0034] By thinning the triangular piece 53, its rigidity is weakened (made more fragile), and even if the triangular piece 53 comes into contact with the side surface of the energy storage device 20, damage to the energy storage device 20 can be suppressed. This prevents the energy storage device 20 from short-circuiting and leading to thermal runaway. As a result, the safety of the energy storage module 10 can be improved in the event that the cell holder 30 is crushed due to an impact on the energy storage module 10.

[0035] Furthermore, the notch 52 allows for improved rigidity of the side wall compared to a side wall of the same thickness that is entirely flat. This improves the strength of the energy storage module 10.

[0036] Using Figures 3 and 4, the gap between the housing portions 41 of the holding portion 40 of the cell holder 30, which is an example of an embodiment, will be described in detail. Figure 3 is a plan view and a partially enlarged view showing the holding portion 40. Figure 4 is a cross-sectional view AA of Figure 3. Note that Figure 4 shows the energy storage device 20.

[0037] As described above, the housing portion 41 includes a bottom portion 43 facing the lower end surface (bottom surface) of the energy storage device 20, a wall portion 44 having an inner circumferential surface facing the side circumferential surface of the lower end of the energy storage device 20, and an opening 45 formed in the bottom portion 43 that exposes the bottom surface of the energy storage device 20.

[0038] The upper end of the wall portion 44 (the opening of the housing portion 41) may be formed to be slightly inclined with respect to the axial direction from the upper surface of the holding portion 40 toward the bottom portion 43. In other words, the wall portion 44 is formed to decrease in diameter from the upper surface of the holding portion 40 toward the bottom portion 43. Because the upper end of the wall portion 44 is inclined in this way, this inclined surface does not come into contact with the side surface of the energy storage device 20. Therefore, when the cell holder 30 is damaged and a triangular piece 48 is generated, the inclined surface of the triangular piece 48 is less likely to come into contact with the energy storage device 20. As a result, the energy storage device 20 is less likely to be damaged by the triangular piece 48.

[0039] The portion of the inner surface of the wall portion 44 where the distance between adjacent housing portions 41 in the holding portion 40 is minimized in a plan view (hereinafter referred to as the portion where the housing portions 41 are close together) is located further from the energy storage device 20 than other portions of the inner surface of the wall portion 44. As a result, the energy storage device 20 and the wall portion 44 do not come into contact in the portion where the housing portions 41 are close together in the holding portion 40.

[0040] Because the thinnest region between the housing sections 41 has the above configuration, if the energy storage module 10 is subjected to an impact and the cell holder 30 is crushed, the sharp-angled portion 49 formed in the adjacent area between the housing sections 41 due to the damage to the holding section 40 will move away from the energy storage device 20 in the radial direction. This prevents the sharp-angled portion 49 from piercing the side surface of the energy storage device 20. As a result, it is possible to prevent the energy storage device 20 from short-circuiting and leading to thermal runaway. Consequently, the safety of the energy storage module 10 can be improved in the event that the energy storage module 10 is subjected to an impact and the cell holder 30 is crushed.

[0041] Using Figure 5, we will describe in detail the side surface of the cell holder 30, which is another example of the embodiment. Figure 5 is a plan view and a partially enlarged view showing the cell holder 30.

[0042] The outer surface of the side wall portion 50 has a notch 46 which is a groove-shaped third notch extending in the axial direction. The notch 46 may be triangular in shape in plan view (a shape in which the area of ​​the bottom of the notch is smaller than the area of ​​the opening) and may be a groove extending in the axial direction, or it may be a plurality of dots arranged in the axial direction.

[0043] By forming a notch 46 on the outer surface of the side wall portion 50, the portion of the side wall portion 50 where the notch 46 is formed becomes thinner. As a result, when an impact is applied to the side of the energy storage module 10, the side wall portion 50 bends in a direction away from the housing portion 41, starting from the notch 46. If further force is applied to the side wall portion 50, the portion of the side wall portion 50 where the notch 46 is formed becomes the starting point for fracture, and the damage to the side wall portion 50 causes the triangular piece 48 formed near the notch 46 (the edge of the holding portion 40) when the cell holder 30 is viewed from above to separate away from the cell holder 30.

[0044] This prevents the triangular piece 48 from piercing the side surface of the energy storage device 20, thereby preventing damage to the energy storage device 20. This also prevents the energy storage device 20 from short-circuiting and leading to thermal runaway. As a result, the safety of the energy storage module 10 can be improved in the event that the cell holder 30 is crushed due to an impact on the energy storage module 10.

[0045] It should be noted that the present invention is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application. For example, although two embodiments have been described in this example, embodiments combining these embodiments are also conceivable.

[0046] Furthermore, the notches 42, the configuration of the adjacent portions of the housing portions 41, and the notches 46 related to the holding portion 40 of the cell holder 30 disclosed in this example can also be applied to the configuration of the lid 60 that holds the upper end of the energy storage device 20. In this case as well, the same functions and effects as those of the notches 42, the configuration of the adjacent portions of the housing portions 41, and the notches 46 described above will be achieved. [Explanation of symbols]

[0047] 10 Energy storage module, 20 Energy storage device, 30 Cell holder, 40 Holding part, 41 Housing part, 42 Notch (first notch), 43 Bottom part, 44 Wall part, 44A Wall part of the adjacent part between housing parts 41, 45 Opening, 46 Notch (third notch), 47 Triangular piece, 48 Triangular piece, 49 Acute angle part, 50 Side wall part, 52 Notch (second notch), 53 Triangular piece, 60 Lid, 110 Energy storage module, 130 Cell holder, 140 Holding part, 141 housing part, 147 triangular piece, 150 side wall part

Claims

1. At least one cylindrical energy storage device, A cell holder housing the aforementioned energy storage device, Equipped with, The cell holder has a holding portion that holds one or the other side of the energy storage device in the axial direction, and a side wall portion that covers the side surface of the energy storage device. The holding portion has at least one housing portion that houses one end or the other end of the energy storage device, and a first notch formed on the side surface of the holding portion along the inner surface of the housing portion. The housing portion includes a wall portion facing the side circumferential surface of one end or the other end of the energy storage device. In the first portion of the wall facing the energy storage device, where the distance between adjacent storage units is minimized, the distance between the storage device and the first portion is greater than in the second portion of the wall excluding the first portion, and the first and second portions are aligned in the circumferential direction of the storage unit. Energy storage module.

2. The energy storage module according to claim 1, The side surface of the holding portion is the outermost outer surface of the holding portion, Energy storage module.

3. The energy storage module according to claim 1, The outer surface of the retaining portion has recesses formed in the region between adjacent housing portions or in the region surrounded by multiple housing portions. The side surface of the retaining portion is a surface that is aligned with the inner surface of the housing portion on the inner surface of the recess. Energy storage module.

4. The energy storage module according to claim 1, The side wall portion is formed extending from the holding portion and is radially separated from the housing portion of the energy storage device. A portion of the energy storage device extends from the housing portion, and a filler material is interposed between the side surface of the extended portion of the energy storage device and the side wall portion. Energy storage module.

5. The energy storage module according to claim 1, The side wall portion has a second notch formed along the side surface of the energy storage device. Energy storage module.

6. A storage module according to any one of claims 1 to 5, The outer surface of the aforementioned side wall portion has a third notch, Energy storage module.

7. The energy storage module according to claim 6, The third notch is formed such that it includes a position where the distance between the housing portion and the side wall portion is minimized when the cell holder is viewed from above. Energy storage module.

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