Energy storage module

Abstract

The present invention provides an electricity storage module which is reduced in size and weight, while enhancing the reliability of a holder. An electricity storage module (10) according to the present invention is provided with: a plurality of arranged cylindrical electricity storage devices (50); and an upper holder (20) which holds the upper end parts of the plurality of electricity storage devices (50), while being provided with a plurality of containing parts (20A) that is formed of a thermoplastic resin. The upper holder (20) comprises an upper support member (25) which is formed of a thermosetting resin and supports electricity storage devices (50) adjacent to each other, while being positioned between the adjacent electricity storage devices (50). In comparison to the thermoplastic resin, the thermosetting resin is not susceptible to deformation or melting even if heat is applied thereto.

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module including an array of cylindrical energy storage devices. [Background technology]

[0002] Conventionally, energy storage modules including an array of multiple energy storage devices have been widely known. For example, Patent Document 1 discloses an energy storage module in which the upper and lower ends of multiple arranged cylindrical batteries are held by holders. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 003468 Summary of the Invention [Problem to be solved by the invention]

[0004] In an energy storage module equipped with multiple cylindrical batteries, if one energy storage device experiences thermal runaway, the holder may soften or melt, causing the thermally runaway energy storage device to approach or come into contact with adjacent energy storage devices, increasing the risk of fire spreading. In the energy storage module of Patent Document 1, the holder is formed from a thermosetting resin in an attempt to solve the problem of thermal runaway, but curable resins are more difficult to process than, for example, thermoplastic resins, and tend to be large when molded. In addition, thermosetting resins have a higher specific gravity than other resins, so the energy storage module tends to be heavy.

[0005] An object of the present disclosure is to provide an electricity storage module that can improve reliability and reduce the size and weight of the holder. [Means for solving the problem]

[0006] An energy storage module according to one aspect of the present disclosure includes an array of multiple cylindrical energy storage devices, and a first holder that holds one end of the multiple energy storage devices and has multiple first storage sections made of a first material formed therein, the first holder having a first support member made of a second material that supports adjacent energy storage devices between them, and the second material having a property that makes it less likely to deform or melt when heat is applied compared to the first material. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, it is possible to provide an energy storage module in which the holder can be made smaller and lighter and which has excellent reliability. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side cross-sectional view showing an example of an electric storage module according to an embodiment; [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a side cross-sectional view showing an electricity storage module as another example of the embodiment. [Figure 5] FIG. 10 is a side cross-sectional view showing a groove portion of the upper support member. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 10 is a side cross-sectional view showing a groove portion of the lower holder. [Figure 9] FIG. 10 is a side cross-sectional view showing a lower holder as another example of the embodiment. [Figure 10] FIG. 4 is a side cross-sectional view showing a lower support member. [Figure 11] FIG. 2 is a side cross-sectional view showing an electricity storage module as another example of the embodiment. [Figure 12] FIG. 2 is a perspective view of the lower holder as seen from below. [Figure 13] 10 is a bottom view of the thermally conductive material accommodated in the lower holder, as viewed from below. FIG. [Figure 14] FIG. 10 is a perspective view of the energy storage module as seen from below for explaining a manufacturing process of the energy storage module. [Figure 15] FIG. 10 is a bottom view of a lower holder of an electricity storage module according to another embodiment, as viewed from below. [Figure 16] FIG. 10 is a perspective view of the energy storage module as seen from below, illustrating a manufacturing process of the conventional energy storage module. BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The shapes, materials, and quantities described below are examples for the purpose of explanation and can be changed as appropriate depending on the specifications of the energy storage module. In the following description, the same reference numerals are used to designate equivalent elements in all drawings.

[0010] An electricity storage module 10 as one example of an embodiment will be described with reference to Fig. 1. Fig. 1 is a side cross-sectional view showing the electricity storage module 10. Fig. 1 is a cross-sectional view taken along line A1-A1 in Fig. 2, which will be described later.

[0011] The power storage module 10 is primarily used as a power source for motive power. The power storage module 10 is 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. However, the use of the power storage module 10 is not limited to a specific purpose, and the module may also 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, other than electric devices.

[0012] The energy storage module 10 includes a plurality of cylindrical energy storage devices 50, an upper holder 20 as a first holder that holds the upper ends of the plurality of energy storage devices 50, and a lower holder 30 as a second holder that holds the lower ends of the plurality of energy storage devices 50. The upper holder 20 and the lower holder 30 will be described in detail later.

[0013] A cylindrical lithium-ion secondary battery is used as the power storage device 50. The power storage device 50 includes an electrode group formed by winding, for example, a strip-shaped positive electrode and a strip-shaped negative electrode with a strip-shaped separator interposed therebetween, a cylindrical outer can containing the electrode group together with an electrolyte, a sealing body that seals the opening of the outer can in an insulated state, a foil-shaped positive electrode lead that electrically connects the positive electrode to the sealing body, and a negative electrode lead that electrically connects the negative electrode to the outer can. An insulating gasket is disposed between the outer periphery of the sealing body and the inner circumferential surface of the opening of the outer can.

[0014] An annular groove is formed on the outer peripheral surface of the outer can on the opening side. A corresponding annular protrusion is formed on the inner peripheral surface of the outer can in this groove. The gasket and sealing body are placed on this annular protrusion inside the outer can. Furthermore, the opening edge of the outer can is crimped so that it tilts toward the inside of the outer can with the gasket placed on the inner peripheral side. The crimped opening edge and the protrusion sandwich the sealing body in the vertical direction (height direction of the energy storage device 50) via the gasket, thereby sealing the opening of the outer can.

[0015] The sealing body may be provided with a current interrupter (CID) or an exhaust valve that ruptures when the pressure inside the outer can reaches a predetermined level or higher. Furthermore, an insulating plate for insulating the electrode group from the outer can may be provided between the electrode group and the bottom of the outer can or between the electrode group and the protrusion (groove). When an 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 bypass the insulating plate.

[0016] In the power storage device 50, a positive electrode terminal as a first terminal is formed on the top surface of the sealing body, and a negative electrode terminal as a second terminal is disposed toward the upper end (the crimped open end) of the outer can. Note that the electrode group may be connected so that the outer can functions as the positive electrode terminal and the sealing body functions as the negative electrode terminal.

[0017] The power storage devices 50 are packed as densely as possible within the power storage module 10, taking safety into consideration, and are arranged so that adjacent power storage devices 50 are substantially close to each other. For example, in a plan view, the power storage devices 50 are arranged so that six power storage devices 50 surround one power storage device 50. Note that the power storage devices 50 may be nickel-metal hydride batteries or capacitors in addition to lithium-ion secondary batteries.

[0018] The power storage device 50 is placed on a thermally conductive material 40. The thermally conductive material 40 is a two-component hardening material made of silicon containing metal oxide (e.g., aluminum oxide, zinc oxide), metal nitride (e.g., aluminum nitride, boron nitride), metal oxynitride (e.g., aluminum oxynitride), or the like. The insulating layer 60 may be a silicon sheet containing a thermally conductive filler. Examples of the heat exchange member 70 include water-cooled piping, air-cooled fins, refrigerant-cooled piping, panel heaters, and sheet heaters.

[0019] The upper holder 20 will be described with reference to Figures 2 and 3. Figure 2 is a plan view showing the upper holder 20. Figure 3 is a part of a cross-sectional view taken along A1-A1 in Figure 2. Note that in Figures 2 and 3, the upper support member 25 is not shown to make the description easier to understand.

[0020] The upper holder 20 has an upper support member 25 (see FIG. 5), which will be described in detail later. The upper holder 20 is formed from a first material. A thermoplastic resin is used as the first material. A thermoplastic resin is a resin that softens when heated to its glass transition point or melting point and hardens when cooled again. Specific examples are broadly classified into general-purpose plastics and engineering plastics, and include polyethylene, polypropylene, polyamide, ABS, etc.

[0021] The thermoplastic resin, which is the first material, contains, for example, at least one of a heat-absorbing filler and a thermally conductive filler, and preferably contains both a heat-absorbing filler and a thermally conductive filler. The heat-absorbing filler exhibits heat absorption upon thermal decomposition, and specific examples include aluminum hydroxide and sodium bicarbonate. Examples of the thermally conductive filler include metal oxides (e.g., aluminum oxide, zinc oxide), metal nitrides (e.g., aluminum nitride, boron nitride), and metal oxynitrides (e.g., aluminum oxynitride).

[0022] 2 and 3, the upper holder 20 has a plurality of accommodation sections 20A that respectively accommodate the upper ends of the power storage devices 50. Each accommodation section 20A has an opening 20C, a protruding section 30B, a partition wall section 20E, a void section 20V, a connection hole 20F, and a groove section 20G formed therein.

[0023] The opening 20C is a portion that exposes a part of the upper end portion of the electricity storage device 50. The opening 20C is formed, for example, in a circular shape. A positive electrode lead portion of a current collector plate (not shown) disposed on the top surface of the upper holder 20 is inserted into this opening 20C, and this positive electrode lead may be joined to a positive electrode terminal of the electricity storage device 50.

[0024] The protruding portion 20D protrudes above the upper end surface of the power storage device 50 so as to surround the opening 20C. The protruding portion 20D is disposed around the opening 20C facing the peripheral edge of the upper end surface of the power storage device 50. The protruding portion 20D may be formed close to the upper end surface of the power storage device 50 and in contact with the upper end surface of the power storage device 50 (for example, the open end of a crimped outer can). The partition portion 20E is formed along the outer peripheral surface of the power storage device 50. The partition portion 20E may be formed close to the outer peripheral surface of the power storage device 50 and in contact with the outer peripheral surface.

[0025] The connection holes 20F are formed in each power storage device 50 in a row in the circumferential direction, similar to the gaps 20V. The connection holes 20F expose a portion of the open end of the outer can from the upper holder 20. A negative electrode lead portion from the current collector plate may be inserted into this connection hole 20F and joined to the open end of the outer can, which serves as a negative electrode terminal. The connection holes 20F are arranged between adjacent gaps 20V in the circumferential direction of one power storage device 50F, and are formed so as to include a location farthest from the adjacent power storage device 50 in this circumferential direction. This configuration prevents the negative electrode lead portion of the current collector plate from being electrically connected to other power storage devices 50. Note that if the negative electrode terminal is formed at the bottom of the outer can, the connection holes 20F may be omitted.

[0026] The voids 20V are spaces filled with a second material, the details of which will be described later. The second material filled in the voids 20V hardens and forms the upper support member 25. The voids 20V are formed between adjacent storage sections 20A. More specifically, they are formed along an axis connecting the center lines of the adjacent storage sections 20A. By arranging the voids 20V in this manner, it is possible to limit the approach of a thermally runaway power storage device 50 to the nearest power storage device 50 by using the second material. Furthermore, the voids 20V are arranged in a row at multiple locations around one power storage device 50.

[0027] The gap 20V is formed by a horizontal gap formed by cutting out a portion of the protruding portion 20D, and a vertical gap formed by cutting out the upper end of the partition wall portion 20E and communicating with the horizontal gap. An injection port is formed in the top surface of the upper holder 20, which defines the gap 20V and through which the second material constituting the upper support member 25 is filled. Note that this injection port does not necessarily have to be formed in the top surface of the upper holder 20, but may be formed in a side surface of the upper holder 20. Furthermore, the opening area of the injection port does not have to be the same as the cross-sectional area of the horizontal gap; the opening area of the injection port may be smaller than the cross-sectional area.

[0028] The length of the horizontal gap in the direction along the cutting line is smaller than the gap between adjacent openings 20C and larger than the gap between adjacent power storage devices 50. The length of the horizontal gap in the direction perpendicular to the axis in the horizontal plane is approximately the same as the gap between adjacent power storage devices 50. The vertical length of the vertical gap is approximately the same as the gap between adjacent power storage devices 50.

[0029] An electricity storage device 50 as another example of the embodiment will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view of the electricity storage device 50 according to the other embodiment taken along the line B1-B1 in Fig. 2.

[0030] In the electricity storage device 50, the diameter of a portion of the upper end is smaller than the diameter of the remaining portion of the electricity storage device 50. For example, one possible configuration of such an electricity storage device 50 is to process the outer can so that the diameter of the portion closer to the opening end than the groove is smaller than the diameter of the portion closer to the bottom than the groove. A space R1 formed by the outer peripheral surface of this small-diameter portion and the partition wall portion 20E is formed in communication with the void portion 20V. As a result, the thermosetting resin filled in the void portion 20V flows into the space R1. The thermosetting resin flowing into the space R1 acts as an adhesive that bonds and fixes the electricity storage device 50 and the upper holder 20 together.

[0031] In the outer can of the energy storage device 50, even if the diameter is the same on the opening end side and the bottom side from the groove and the space partitioned by the groove and the partition wall 20E is connected to the gap 20V, the support function is improved compared to a configuration in which the energy storage device 50 is supported only by the upper support member 25 in the gap 20V of the energy storage device 50 of the upper support member 25, but making the diameter smaller on the opening end side from the groove than on the bottom side makes it easier to increase the amount of the second material that comes into contact with the energy storage device 50 in the height direction of the energy storage device 50. In addition, a similar effect may be obtained by providing a portion with a smaller diameter than the remainder in the portion housed in the lower holder 30 on the other end side of the energy storage device 50 (particularly the bottom of the outer can) described later.

[0032] The upper support member 25 will be described with reference to Fig. 5. Fig. 5 is a cross-sectional view of the upper holder 20 provided with the upper support member 25, taken along line A1-A1 in Fig. 2.

[0033] The upper support member 25 is located between the adjacent power storage devices 50 and supports the adjacent power storage devices 50. The upper support member 25 is formed by filling the second material into the gap portion 20V from the filling port of the upper holder 20 described above.

[0034] The upper support member 25 is formed of a second material that is less likely to deform or melt when heated than the first material. A thermosetting resin is used as the second material. The thermosetting resin is a resin with a cross-linked structure that does not melt even when exposed to high temperatures of 600°C or higher, and even when exposed to high temperatures of, for example, 800°C to 1000°C, it does not melt but carbonizes, maintaining the shape of the upper support member 25. Specific examples of thermosetting resins include urethane resin, silicone resin, unsaturated polyester, epoxy resin, melamine resin, and phenolic resin.

[0035] The upper support member 25 is formed in an approximately T-shape when viewed from the side, and is composed of a base 25D that spans the upper end surfaces of adjacent storage devices 50, and an upright portion 25E that is erected on the base 25D and inserted between the outer peripheral surfaces of adjacent storage devices 50.

[0036] Base portion 25D is a portion formed by filling the second material into the horizontal gap of gap portion 20V. Base portion 25D abuts against the upper end surfaces of adjacent energy storage devices 50. Furthermore, standing portion 25E is a portion formed by filling the second material into the vertical gap of gap portion 20V. Standing portion 25E abuts against the outer circumferential surfaces of adjacent energy storage devices 50.

[0037] With this configuration, rather than providing each upper support member 25 for each of the adjacent energy storage devices 50 in the direction in which the adjacent energy storage devices 50 face each other, the base portion 25D and the upright portion 25E can easily align the energy storage device 50 that has experienced thermal runaway with the adjacent energy storage device 50. Furthermore, the work of arranging the second material around the energy storage device 50 to form the upper support member 25 can be simplified. Also, the reliability of alignment when the energy storage device 50 experiences thermal runaway is improved if the upper support member 25 is in direct contact with the energy storage device 50 without the first material constituting the housing portion 20A being interposed therebetween. The partition portion 20E has an opening on the surface facing the outer circumferential surface of the energy storage device 50.

[0038] The following describes the effects of the energy storage module 10. With the energy storage module 10, the upper holder 20 is made of a first material, and only the upper support member 25, which is a part of the upper holder 20, is made of a second material that is less likely to deform or melt when heat is applied than the first material, and the lower holder 30 is made of the first material, and only the lower support member 35, which is a part of the lower holder 30, is made of the second material, thereby making it possible to reduce the size and weight of the energy storage module 10 compared to when the upper holder 20 and the lower holder 30 are made of the first material.

[0039] In conventional energy storage modules, excess thermally conductive material escapes into the gaps between the energy storage devices. In other words, the excess thermally conductive material escapes into the open space. Therefore, the energy storage module cannot limit the amount of thermally conductive paste that escapes. In other words, it cannot absorb variations in the amount of thermally conductive material interposed between the energy storage device and the thermally conductive sheet. This ultimately leads to variations in the distance from the energy storage device to the heat exchanger, the contact area between the energy storage device and the thermally conductive material, and the contact area between the thermally conductive material and the heat exchanger. This results in variations in the amount of heat dissipation from the energy storage device to the heat exchanger. Below, we describe an energy storage module that can suppress variations in the amount of heat dissipation from the energy storage device to the heat exchanger due to variations in the amount of thermally conductive material applied.

[0040] The lower holder 30 will be described with reference to Figures 6 and 7. Figure 6 is a plan view showing the lower holder 30. Figure 7 is a cross-sectional view taken along line A2-A2 in Figure 6. Note that in Figures 6 and 7, the lower support member 35 is omitted from the illustration in order to make the description easier to understand.

[0041] The lower holder 30 includes a lower support member 35, the details of which will be described later. The lower holder 30 is formed of a first material. The first material is the same as the first material forming the upper holder 20, and therefore a description thereof will be omitted. The lower holder 30 has a plurality of accommodating sections 30A into which the other axial end (lower end) of each power storage device 50 is inserted. The accommodating sections 30A are formed with an opening 30C, a protruding section 30B, a partition section 30E, a void section 30V, a groove section (not shown), and a recessed section 30H. The groove section will be described in detail later.

[0042] The opening 30C is a through-hole extending from the accommodation portion 30A toward the lower end surface of the lower holder 30, and is a portion filled with the thermally conductive material 40 of the electricity storage device 50. The opening 30C is formed, for example, in a circular shape. The protruding portion 30D protrudes below the lower end surface of the electricity storage device 50 so as to surround the opening 30C. The protruding portion 30D is disposed around the opening 30C facing the peripheral edge of the lower end surface of the electricity storage device 50. The protruding portion 30D is formed close to the lower end surface of the electricity storage device 50 and may be in contact with the lower end surface of the electricity storage device 50. The partition portion 30E is formed along the outer circumferential surface of the electricity storage device 50. The partition portion 30E is formed close to the outer circumferential surface of the electricity storage device 50 (external can), and may be in contact with the outer circumferential surface.

[0043] The void 30V is a space filled with the second material described above. The second material filled in the void 30V hardens and forms the lower support member 35. The void 30V is formed between adjacent storage sections 30A. More specifically, it is formed along an axis connecting the center lines of the adjacent storage sections 30A. The void 30V is formed by a horizontal gap formed by cutting out a portion of the protruding section 30D, and a vertical gap formed by cutting out the lower end of the partition section 30E and communicating with the horizontal gap.

[0044] The length of the horizontal gap in the direction in which adjacent power storage devices 50 are lined up is smaller than the gap between adjacent openings 30C and larger than the gap between adjacent power storage devices 50. The length of the horizontal gap in the direction perpendicular to the axis in the horizontal plane is approximately the same as the gap between adjacent power storage devices 50. The vertical length of the vertical gap is approximately the same as the gap between adjacent power storage devices 50.

[0045] The recesses 30H are portions for accommodating excess thermally conductive material 40. The recesses 30H are formed around the protruding portion 30D. The recesses 30H are formed in a stepped shape, rising one step from the lower end surface of the protruding portion 30D. The recesses 30H formed in each accommodating portion 30A are interconnected. Some of the recesses 30H are formed within the void portion 30V and are interconnected with the void portion 30V. The recesses 30H are formed away from the periphery of the opening 30C on the lower end surface of the lower holder 30. This configuration allows the thermally conductive material 40 accommodated in the recesses 30H to be more reliably spaced apart. The recesses 30H also extend in the circumferential direction of the opening on the lower end surface so as to surround the entire periphery of the opening. This configuration allows excess thermally conductive material near the opening 30C to be more reliably accommodated in the recesses 30H. Here, the lower end surface of the lower holder 30 where the recess is formed means the outer surface of the lower holder 30 facing the heat exchange member, and does not necessarily mean the surface at the lower end of the lower holder 30.

[0046] Recess 30H formed within gap 30V is defined by at least one of gap 30V and lower support member 35. With this configuration, gap 30V functions as a space for arranging lower support member 35, and recess 30H can accommodate thermally conductive material 40. Therefore, lower support member 35 may be arranged to occupy a portion of gap 30V. Note that in the present disclosure, recess 30H can accommodate thermally conductive material 40 when excess thermally conductive material 40 is generated, and therefore recess 30H does not necessarily have to accommodate thermally conductive material 40.

[0047] The groove portion 30G formed in the lower holder 30 will be described with reference to Fig. 8. Fig. 8 is a cross-sectional view taken along B2-B2 in Fig. 6, and is a schematic cross-sectional view illustrating an extract of the vicinity of the periphery of the accommodation portion 30A of the lower holder 30 and the other end side of the electricity storage device 50.

[0048] 8, groove 30G is a space into which the second material filled in gap 30V flows. The second material that flows into groove 30G acts as an adhesive that bonds and fixes the electricity storage device 50 and the lower holder 30. Groove 30G is formed along the circumferential direction of the electricity storage device 50 on the surface of partition wall 30E that faces the outer circumferential surface of the electricity storage device 50. Groove 30G is also formed so as to communicate with gap 30V.

[0049] With this configuration, when the second material is filled into the gap 30V, a portion of the second material can flow from the gap 30V into the substantially annular gap defined by the groove 30G and the outer peripheral surface of the outer can. This increases the amount of the second material that comes into contact with the energy storage device 50 in the circumferential direction of the energy storage device 50, allowing the lower support member 35 to more reliably support the energy storage device 50. The cross-sectional shape of the groove 30G may be, for example, a V-shape. In this embodiment, the groove 30G is formed on the surface of the partition wall 30E facing the outer peripheral surface of the energy storage device 50, but is not limited thereto. For example, the groove 30G may be formed on the surface of the protruding portion 30D facing the upper end surface of the energy storage device 50.

[0050] The lower holder 30, which is another example of the embodiment, will be described with reference to Fig. 9. Fig. 9 is a cross-sectional view taken along B2-B2 in Fig. 6 in the case of the lower holder 30 of another embodiment.

[0051] The lower holder 30 has a corner formed by the protruding portion 30D and the partition wall portion 30E. The corner that forms the lower end surface and outer peripheral surface of the electricity storage device 50 (or the outer can) is rounded. A space R2 formed by the corner of the lower holder 30 and the rounded portion of the electricity storage device 50 is formed in communication with the gap 30V. This allows the thermosetting resin filled in the gap 30V to flow into the space R2. The thermosetting resin that has flowed into the space R2 acts as an adhesive that bonds and fixes the electricity storage device 50 and the lower holder 30 together.

[0052] The lower support member 35 and the heat conductive material 40 will be described with reference to Fig. 10. Fig. 10 is a cross-sectional view of the lower holder 30 provided with the lower support member 35, taken along line B2-B2 in Fig. 6.

[0053] The lower support member 35 supports adjacent power storage devices 50 between the adjacent power storage devices 50. The lower support member 35 is formed by filling the gap 30V of the lower holder 30 described above. The lower support member 35 is formed from a second material. A thermosetting resin is used as the second material. The second material forming the lower holder 30 is the same as the second material forming the upper holder 20, and therefore a description thereof will be omitted.

[0054] The lower support member 35 is formed in an approximately T-shape when viewed from the side, and has a base portion 35D that spans the lower end surfaces of adjacent storage devices 50, and an upright portion 35E that is inserted between the outer peripheral surfaces of adjacent storage devices 50.

[0055] Similar to the upper support member 25, the base 35D is a portion formed by filling the horizontal gap of the gap 30V with the second material. The base 35D abuts against the upper end surfaces of the adjacent energy storage devices 50. Furthermore, the standing portions 35E standing from the base 35D are portions formed by filling the vertical gap of the gap 30V with the second material. The standing portions 35E abut against the outer peripheral surfaces of the adjacent energy storage devices 50.

[0056] When lower support member 35 is formed by filling gap 30V, because gap 30V and groove 30G are in communication with each other, lower support member 35 also fills groove 30G. This allows lower support member 35 to be used as a thermosetting resin adhesive to bond lower holder 30 and electricity storage device 50 together.

[0057] The thermally conductive material 40 is formed by filling the opening 30C of the lower holder 30. After the thermally conductive material 40 is filled in the opening 30C, the power storage device 50 is placed on the thermally conductive material 40 in the accommodation section 30A. At this time, excess thermally conductive material 40 flows into the gap between the protruding portion 30D of the lower holder 30 and the insulating layer 60, and is pushed out toward the recess 30H and accommodated in the recess 30H. This prevents the thermally conductive material 40 that has flowed into the gap between the protruding portion 30D of the lower holder 30 and the insulating layer 60 from remaining in the gap between the protruding portion 30D and the insulating layer 60. Note that the recess 30H in FIG. 10 is formed on the surface exposed from the opening of the gap 30V of the lower support member 35.

[0058] This makes it possible to suppress variations in the distance between the electricity storage device 50 and the insulating layer 60, and to suppress variations in the heat transfer property between each electricity storage device 50 and the heat exchange member 70. Furthermore, the recess 30H may be arranged so as not to overlap with the electricity storage device 50 in the height direction of the electricity storage device 50. With this configuration, it is possible to suppress variations in the heat transfer property between the end face of the electricity storage device 50 (or the bottom of the outer can) and the heat exchange member 70, regardless of whether or not the thermally conductive material 40 is housed in the recess 30H.

[0059] The following describes the effects of the power storage module 10. The power storage module 10 can suppress variations in the amount of heat released from the power storage device 50 to the heat exchange member 70 that are caused by variations in the amount of heat conductive material 40 applied.

[0060] FIG. 16 is a perspective view of the power storage module 210 as seen from below, illustrating the manufacturing process of the power storage module 210, and shows some of the components in cross section.

[0061] In Figure 16, the energy storage module 210 includes a lower holder 240 that holds the lower end portion 220A of the energy storage device 220, a heat exchange member 250 that is arranged below the lower holder 240, a heat conductive material 260 that thermally connects the lower end portion 220A of the energy storage device 220 to the heat exchange member 250, and an insulating layer 270 that electrically insulates the energy storage device 220 from the heat exchange member 250.

[0062] The lower holder 240 is formed with an accommodation section 241 that accommodates the lower end section 220A of the power storage device 220, an opening 242 that penetrates downward from the accommodation section 241, and a peripheral wall 243 that is formed on the bottom surface of the lower holder 240 at the edge of the opening 242, and a thermally conductive material 260 is accommodated on the inner circumferential side of the opening 242 and the peripheral wall 243 (hereinafter referred to as a filling section 244). The thermally conductive material 260 is a viscous fluid that is in a gel state and hardens after a predetermined time has passed.

[0063] In the manufacturing process of the power storage module 210, the lower end 220A of the power storage device 220 is accommodated in the accommodation portion 241 of the lower holder 240, the thermally conductive material 260 is applied to the filling portion 244 of the lower holder 240, an insulating layer 270 is interposed between the lower holder 240 and the heat exchange member 250, and the heat exchange member 250 is pressed toward the lower holder 240. At this time, the thermally conductive material 260 is compressed and spread in the filling portion 244, and the thermally conductive material 260 is filled into the filling portion 244 without any gaps. The amount of thermally conductive material 260 applied to the filling portion 244 of the lower holder 240 is equal to the volume of the filling portion 244 plus a surplus amount.

[0064] When the heat exchange member 250 is pressed toward the lower holder 240 during the manufacturing process of the power storage module 210 described above, excess thermally conductive material 260 may exceed the peripheral wall 243 and be discharged from the filling portion 244 to the outer periphery of the peripheral wall 243. However, if the pressure acting on the filling portion 244 is small, the excess thermally conductive material 260 may not be sufficiently discharged from the filling portion 244. Furthermore, it is difficult to apply uniform pressure to multiple filling portions.

[0065] Therefore, there is a risk that variations will occur in the thickness (vertical size) of each thermally conductive material 260, and that variations will occur in the heat dissipation distance (the distance from the lower end 220A of the power storage device 220 to the heat exchange member 250) of each power storage device 220. If the heat dissipation distance varies, the heat dissipation performance of the power storage device 220 will become uneven, and the overall heat dissipation performance of the power storage module 210 will decrease.

[0066] The following describes an electricity storage module 110 that can reduce variations in thickness of the thermally conductive material and improve heat dissipation performance.

[0067] An electricity storage module 110, which is another example of an embodiment, will be described with reference to Fig. 11. Fig. 11 is a side cross-sectional view showing the electricity storage module 110.

[0068] The power storage module 110 is primarily used as a power source for motive power. The power storage module 110 is used as a power source for motor-driven electric devices such as electric vehicles, power tools, power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the use of the power storage module 110 is not limited to a specific purpose, and the power storage module 110 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.

[0069] The energy storage module 110 includes a plurality of cylindrical energy storage devices 120, an upper holder 130 that holds the upper ends of the plurality of energy storage devices 120, a lower holder 140 that serves as a holder that holds the lower ends 120A of the plurality of energy storage devices 120, a heat exchange member 150 that faces the bottom surface of the lower holder 140, a heat conductive material 160 that thermally connects the energy storage devices 120 and the heat exchange member 150, and an insulating layer 170 that electrically insulates the energy storage devices 120 and the heat exchange member 150.

[0070] In this example, a cylindrical lithium-ion secondary battery is used as the power storage device 120, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 120 includes an electrode group in which, for example, a strip-shaped positive electrode and a strip-shaped negative electrode are wound with a strip-shaped separator interposed therebetween, a cylindrical outer can that houses the electrode group together with an electrolyte, a seal that seals the opening of the outer can in an insulated state, a foil-shaped positive electrode lead that electrically connects the positive electrode to the seal, and a negative electrode lead that electrically connects the negative electrode to the outer can. An insulating gasket may be disposed between the outer periphery of the seal and the inner circumferential surface of the opening of the outer can.

[0071] An annular groove is formed on the outer peripheral surface of the outer can, on the opening side. This groove is formed as an annular protrusion on the inner peripheral surface of the outer can. The gasket and sealing body are placed on this annular protrusion inside the outer can. Furthermore, the opening edge of the outer can is crimped so that it tilts toward the inside of the outer can, with the gasket placed on the inner peripheral side. The crimped opening edge and the protrusion sandwich the sealing body in the vertical direction via the gasket, thereby sealing the opening of the outer can.

[0072] The sealing body may be provided with a current interrupter (CID) or an exhaust valve that ruptures when the pressure inside the outer can reaches a predetermined level or higher. Furthermore, an insulating plate for insulating the electrode group from the outer can may be provided between the electrode group and the bottom of the outer can or between the electrode group and the protrusion (groove). When an 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 bypass the insulating plate.

[0073] In the power storage device 120, the positive electrode terminal is formed on the top surface of the sealing body, and the negative electrode terminal is disposed toward the upper end (the crimped open end) of the outer can. Note that the electrode group may be connected so that the outer can functions as the positive electrode terminal and the sealing body functions as the negative electrode terminal.

[0074] The multiple power storage devices 120 may be packed as densely as possible within the power storage module 110, taking safety into consideration, and may be arranged so that adjacent power storage devices 120 are substantially close to each other. For example, in a plan view, the power storage devices 120 are arranged such that six power storage devices 120 surround one power storage device 120. The multiple power storage devices 120 may be connected in series or in parallel via conductive current collector plates (not shown). In this case, the positions at which the leads extending from the current collector plates are connected to the power storage devices may be the top surface of the sealing body as the positive terminal and the open end of the crimped outer can as the negative terminal.

[0075] As described above, the upper holder 130 is a member that holds the upper ends of the plurality of power storage devices 120. The upper holder 130 is made of, for example, a thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and polyethylene, polypropylene, polyamide, ABS, etc. are used.

[0076] As described above, lower holder 140 is a member that holds lower ends 120A of multiple power storage devices 120 and accommodates thermally conductive material 160. Lower holder 140 is made of thermoplastic resin, similar to upper holder 130. The shape of lower holder 140 will be described in detail later.

[0077] The heat exchange member 150 is a member that is disposed, for example, opposite the bottom surface of the lower holder 140, and cools the lower end portion 120A of the power storage device 120. In this example, a thermally conductive plate-shaped metal is used for the heat exchange member 150, but it may also be a water-cooled pipe, an air-cooled fin, a refrigerant-cooled pipe, a panel heater, a seat heater, or the like.

[0078] The thermal conductive material 160 is a member that is interposed between the power storage device 120 and the heat exchange member 150 and that thermally connects the power storage device 120 and the heat exchange member 150. The thermal conductive material 160 is a viscous fluid, and is a gel-like material that hardens after a predetermined time has passed. In this example, the thermal conductive material 160 is a two-component hardening material that is silicon, and contains metal oxide (e.g., aluminum oxide, zinc oxide), metal nitride (e.g., aluminum nitride, boron nitride), metal oxynitride (e.g., aluminum oxynitride), or the like.

[0079] The insulating layer 170 is a sheet-like member that is interposed between the lower end portion 120A of the power storage device 120 and the heat exchange member 150, and that insulates the power storage device 120 from the heat exchange member 150. In this example, a silicon sheet containing a thermally conductive filler is used as the insulating layer 170, but the insulating layer 170 is not limited to this.

[0080] The shape of lower holder 140 will be described with reference to Figure 12. Figure 12 is a perspective view of lower holder 140 seen from below, with some of the members shown in cross section.

[0081] 12, lower holder 140 holds lower end portions 120A of a plurality of power storage devices 120 as described above, and also houses thermally conductive material 160 (see FIGS. 13 and 14). Lower holder 140 has at least one housing portion 141 that houses lower end portion 120A of at least one power storage device 120, an opening portion 142 that penetrates downward from at least one housing portion 141, and at least one peripheral wall 143 that is formed on the bottom surface of lower holder 140 at the edge of opening portion 142.

[0082] A plurality of accommodation sections 141 are formed on the bottom surface of the lower holder 140, and accommodate the lower end section 120A of the power storage device 120. By accommodating the lower end section 120A of the power storage device 120 in the accommodation sections 141, the lower end section 120A of the power storage device 120 is held by the lower holder 140. Note that in this embodiment, the lower end section 120A of the power storage device 120 is the bottom of the outer casing, but the power storage module of the present disclosure is not limited to this configuration. For example, the lower end section 120A may be on the sealing plate side.

[0083] Opening 142 is a circular opening at the bottom of housing 141. Opening 142 allows the bottom of power storage device 120 to be seen, and allows power storage device 120 to be thermally connected to thermally conductive material 160. The diameter of opening 142 is smaller than the diameter of the bottom.

[0084] The peripheral wall 143 is a portion formed on the bottom surface of the lower holder 140 at the edge of the opening 142. The peripheral wall 143, together with the opening 142, can form a space (a filling portion 144, described later) for accommodating the thermally conductive material 160. The peripheral wall 143 is formed in a downwardly convex shape along the opening 142. The peripheral wall 143 has a plurality of notches 145, described later.

[0085] Here, the space formed on the inner circumferential side of the opening 142 and the peripheral wall 143 is referred to as the filling section 144. The filling section 144 can accommodate the thermally conductive material 160 to thermally connect the lower end 120A of the power storage device 120 and the heat exchange member 150. More specifically, the filling section 144 is defined by the bottom surface of the power storage device 120, the ceiling surface of the insulating layer 170, and the inner circumferential surfaces of the opening 142 and the peripheral wall 143. In the filling section 144, the hole defined by the inner circumferential surface of the opening 142 and the hole in the inner circumferential surface of the peripheral wall 143 may have the same shape and size. This configuration facilitates the formation of the opening and the peripheral wall. Furthermore, it also facilitates the arrangement of the peripheral wall on the bottom surface of the lower holder 140.

[0086] The notch 145 is a portion formed by cutting out a part of the peripheral wall 143. Although details will be described later, the notch 145 allows excess thermal conductive material 160 to be discharged to the outer periphery side of the peripheral wall 143 during the manufacture of the power storage module 110. The notch 145 is formed so as to communicate between the outer periphery side and the inner periphery side of the peripheral wall 143.

[0087] In this example, a plurality of notches 145 are formed at approximately equal intervals in the circumferential direction of the peripheral wall 143. The notches 145 allow excess thermal conductive material 160 to be discharged approximately evenly in the circumferential direction toward the outer periphery of the peripheral wall 143. This reduces variation in the amount of excess thermal conductive material 160 discharged in the circumferential direction of the filling portion 144. In this example, four notches 145 are formed at 90° intervals in the circumferential direction, but this is not limited to this. Note that in this example, the notches 145 extend in the height direction (up and down direction) of the peripheral wall 143. The height dimension of the notches 145 is the same as the height dimension of the peripheral wall 143 (the height dimension of the outer circumferential surface of the peripheral wall 143). This configuration makes it possible to easily push excess thermal conductive material 160 out of the peripheral wall 143. However, the notches 145 of the present disclosure are not limited to this configuration. The size of the notch 145 in the height direction may be smaller than the size of the peripheral wall 143 in the height direction. In this case, the peripheral wall 143 is annular and has no gaps in the circumferential direction.

[0088] The shape of the thermally conductive material 160 will be described using Figure 13. Figure 13 is a bottom view of the thermally conductive material 160 accommodated in the lower holder 140, as viewed from below. In Figure 13, the thermally conductive material 160 is accommodated in the filling portion 144. In a manufacturing process described below, the thermally conductive material 160 is applied to the filling portion 144 in an amount that is equal to the capacity of the filling portion 144 plus an excess amount. The excess thermally conductive material 160 is formed on the outer periphery of the peripheral wall 143, and particularly protrudes near the notch 145 on the outer periphery of the peripheral wall 143.

[0089] The manufacturing process of the power storage module 110 will be described with reference to Fig. 14. Fig. 14 is a perspective view of the power storage module 110 as seen from below, illustrating the manufacturing process of the power storage module 110, and shows some of the components in cross section.

[0090] 14, in the manufacturing process of the power storage module 110, the power storage device 120 is housed in the lower holder 140, the thermally conductive material 160 is applied to the filling portion 144 of the lower holder 140, an insulating layer 170 is interposed between the lower holder 140 and the heat exchange member 150, and the heat exchange member 150 is pressed toward the lower holder 140. At this time, the thermally conductive material 160 is compressed and spread in the filling portion 144, and the thermally conductive material 160 fills the filling portion 144 without any gaps. Note that in the present invention, the thermally conductive material 160 does not necessarily fill the filling portion 144 without any gaps. However, the fewer gaps there are, the higher the thermal conductivity of the thermally conductive material 160. Furthermore, when the heat exchange member 150 is fixed to the lower holder 140 by a fixing portion (not shown), the tip of the peripheral wall 143 in the height direction (vertical direction) may abut against the heat exchange member 150 (or the insulating layer 170 if the insulating layer 170 is provided). In other words, the tip of the peripheral wall 143 may abut against the heat exchange member 150 directly or indirectly. This configuration makes it easy to adjust the heat release distance between the power storage device 120 and the heat exchange member 150. Furthermore, in order to abut against the heat exchange member 150, the tip of the peripheral wall 143 may protrude most downward from the bottom surface of the lower holder 140.

[0091] As described above, the amount of thermally conductive material applied to the filling portion 144 of the lower holder 140 is equal to the volume of the filling portion 144 plus a surplus amount. Therefore, in the energy storage module, the total volume of the thermally conductive material may be larger than the total volume of the filling portion (the cavity in the opening 142 and the cavity in the peripheral wall 143). Furthermore, at the stage where the heat exchange member 150 is pressed toward the lower holder 140, the thermally conductive material 160 is in a viscous fluid state.

[0092] When the heat exchange member 150 is pressed toward the lower holder 140, excess heat conductive material 160 passes over the peripheral wall 143 and is discharged from the filling portion 144 to the outer periphery of the peripheral wall 143. At the same time, excess heat conductive material 160 is also discharged from the notch 145 of the peripheral wall 143 to the outer periphery of the peripheral wall 143.

[0093] This allows excess thermally conductive material 160 to be sufficiently discharged from filling portion 144, eliminating variations in the thickness (vertical dimension) of each thermally conductive material 160 and suppressing variations in the heat dissipation distance (distance from lower end 120A of power storage device 120 to heat exchange member 150) of each power storage device 120. As a result, variations in the heat dissipation performance of power storage device 120 are suppressed, and the heat dissipation performance of power storage module 110 is improved.

[0094] The lower holder 140 of the power storage module 110, which is another example of the embodiment, will be described with reference to Fig. 15. Fig. 15 is a bottom view of the lower holder 140 as viewed from below.

[0095] 15, as described above, the lower holder 140 has an opening 142 formed by penetrating downward from the accommodation portion 141, and a peripheral wall 143 formed on the edge of the opening 142 on the bottom surface of the lower holder 140. A plurality of notches 145 are formed in the peripheral wall 143.

[0096] As described above, the cutout 145 is a portion formed by cutting out a part of the peripheral wall 143, and is formed so as to communicate between the outer peripheral side and the inner peripheral side of the peripheral wall 143. In this example, the cutout 145 may be formed in the circumferential direction of the peripheral wall 143, excluding the portion of the peripheral wall 143 that is close to the adjacent peripheral wall 143. In other words, the cutout 145 may be formed in the circumferential direction of the peripheral wall 143, excluding the portion of the peripheral wall 143 that is closest to the adjacent peripheral wall 143. For example, the cutout 145 is formed so as to communicate with a wide region on the outer peripheral side of the peripheral wall 143. Here, the wide region is a region where the distance between adjacent peripheral walls 143 is at least 220% or more of the narrowest distance. The narrowest distance is the distance at which adjacent peripheral walls 143 are closest to each other.

[0097] Even with the notches 145 of this example, when the heat exchange member 150 is pressed toward the lower holder 140 during the manufacturing process of the power storage module 110, the excess heat conductive material 160 is also more easily discharged from the notches 145 of the peripheral wall 143 to the outer periphery side of the peripheral wall 143. Furthermore, with the notches 145 of this example, the excess heat conductive material 160 is discharged to a wide region on the outer periphery side of the peripheral wall 143, so that the discharge of the heat conductive material 160 is less likely to be obstructed by the adjacent peripheral wall 143, and the excess heat conductive material 160 is discharged smoothly.

[0098] This allows excess thermally conductive material 160 to be sufficiently discharged from filling portion 144, further reducing variations in the thickness (vertical dimension) of each thermally conductive material 160, and reducing variations in the heat dissipation distance of each power storage device 120. As a result, variations in the heat dissipation performance of power storage devices 120 are reduced, and the heat dissipation performance of power storage module 110 is improved.

[0099] Furthermore, the power storage module 110 may have multiple power storage devices 120, multiple housing sections 141, and multiple peripheral walls, and the heat exchange member 150 and the lower holder 140 may be fixed by a fixing section (not shown). When there is a peripheral wall (first peripheral wall) closer to the fixing section and a peripheral wall (second peripheral wall) farther from the fixing section, the peripheral wall closer to the fixing section may have a smaller cutout (larger volume) than the peripheral wall farther from the fixing section, or may have no cutout at all. With this configuration, the thermally conductive material in the filling section farther from the fixing section is more likely to be pushed out due to variations in the force generated by the heat exchange member 150. Note that examples of fixing means at the fixing section include, but are not limited to, fastening using screws and screw holes. [Explanation of symbols]

[0100] 10 Energy storage module, 20 Upper holder, 20A Storage section, 20C Opening, 20D Protruding section, 20E Partition wall section, 20F Connection hole, 20G Groove section, 20V Void section, 25 Upper support member (first support member), 25D Base section, 25E Standing section, 30 Lower holder, 30A Storage section, 30B Protruding section, 30C Opening, 30D Protruding section, 30E Partition wall section, 30G Groove section, 30H Recess, 30V Void section, 35 Lower support member (second support member), 35D Base section, 35E Standing section, 40 Thermal conductive material, 50 Energy storage device, 110 Energy storage module, 120 Energy storage device, 120A Lower end section, 130 Upper holder, 140 Lower holder, 141 Storage section, 142 opening, 143 peripheral wall, 144 filling section, 145 notch, 150 heat exchange member, 160 thermally conductive material, 1200 energy storage module, 220 energy storage device, 220 bottom, 240 lower holder, 241 opening, 242 peripheral wall, 244 filling section, 250 heat exchange member, 260 thermally conductive material.

Claims

1. A plurality of arranged cylindrical electricity storage devices; a first holder that holds one end portion of the plurality of power storage devices and has a plurality of first housing portions made of a first material; Equipped with the first holder has a first support member between the adjacent power storage devices that supports the adjacent power storage devices and that is made of a second material; the second material has a property of being less likely to deform or melt when heated compared to the first material; The first support member has a base portion that spans one end surface of each of the adjacent power storage devices, and an upright portion that stands on the base portion and is inserted between the outer peripheral surfaces of the adjacent power storage devices. Energy storage module.

2. The energy storage module according to claim 1, the first support member abuts against one end surface of each of the adjacent power storage devices; Energy storage module.

3. The energy storage module according to claim 1 or 2, the first support member abuts against outer peripheral surfaces of the adjacent power storage devices, Energy storage module.

4. The energy storage module according to any one of claims 1 to 3, the first support member is disposed in a gap formed in the first holder; a groove portion is formed in the first housing portion of the first holder on a surface facing the power storage device and extending in a circumferential direction of the power storage device; the groove portion communicates with the gap, The second material is disposed in the groove. Energy storage module.

5. The energy storage module according to claim 4, The diameter of one end of the power storage device is smaller than the diameter of the other portion of the power storage device. Energy storage module.

6. The energy storage module according to claim 5, an inner circumferential surface of the first housing portion of the first holder abuts against an outer circumferential surface of a large diameter portion of the power storage device; Energy storage module.

7. The energy storage module according to claim 4, An injection hole communicating with the gap is formed on the outer surface of the first holder. Energy storage module.

8. The energy storage module according to claim 4, the gap is formed by the first holder and an outer surface of the adjacent electricity storage device; Energy storage module.

9. A plurality of cylindrical electricity storage devices are provided, The power storage device has a first terminal and a second terminal disposed at one end thereof, The plurality of power storage devices are arranged so that the ends of the one side are on the same side, a second holder made of a first material and configured to hold the other sides of the plurality of power storage devices; the second holder has a second support member between the adjacent power storage devices that supports the adjacent power storage devices and that is made of a second material; the second material has a property of being less likely to deform or melt when heated compared to the first material; the second support member is disposed in a cavity formed in the second holder, a groove portion is formed in a surface of the second holder facing the power storage device along a circumferential direction of the power storage device; the groove portion communicates with the gap, The second material is disposed in the groove. Energy storage module.

10. The energy storage module according to claim 2, each of the plurality of power storage devices includes an electrode group including a first electrode and a second electrode, a cylindrical outer can that houses the electrode group together with an electrolyte, and a sealing body that seals an opening of the outer can in a state where the sealing body is electrically insulated from the outer can; the sealing body is electrically connected to the first electrode, the outer can is electrically connected to the second electrode, The one end surface is a top surface of the sealing body. Energy storage module.

11. A plurality of arranged cylindrical electricity storage devices; a first holder that holds one end portion of the plurality of power storage devices and has a plurality of first housing portions made of a first material; Equipped with the first holder has a first support member between the adjacent power storage devices that supports the adjacent power storage devices and that is made of a second material; the second material has a property of being less likely to deform or melt when heated compared to the first material; The plurality of power storage devices have one end and the other end in a first direction, a second holder having a plurality of second accommodating portions formed therein for accommodating other end portions of the plurality of power storage devices; a heat exchange member facing an end surface of the second holder; a heat conductive material that thermally connects the plurality of power storage devices and the heat exchange member; The second holder has a plurality of openings formed therein, each of which is a through hole extending from the second housing portion toward the end surface, The thermally conductive material is contained within the opening; A recess is formed around the opening on the end surface. Energy storage module.

12. The energy storage module according to claim 11, The thermally conductive material is accommodated in the recess. Energy storage module.

13. The energy storage module according to claim 11 or 12, The recess is formed on the end surface at a location spaced from the periphery of the opening. Energy storage module.

14. The energy storage module according to any one of claims 11 to 13, When viewed from the first direction, the other end of the power storage device does not overlap with the recess. Energy storage module.

15. The energy storage module according to any one of claims 11 to 14, The second holder has a gap formed between a pair of adjacent second housing portions, the gaps communicate with the pair of second housing portions, the second holder has a second support member accommodated in the gap, the second holder is made of the first material; the second support member is made of the second material; The gap is open at the end surface, The second support member is exposed from the opening of the gap at the end surface. Energy storage module.

16. The energy storage module according to claim 15, the recess is defined by an inner surface of the gap and the second support member. Energy storage module.

17. The energy storage module according to claim 16, The recess is formed on a surface of the second support member exposed from an opening of the gap. Energy storage module.

18. The storage module according to any one of claims 11 to 17, The recess surrounds the entire periphery of the opening. Energy storage module.

19. The storage module according to any one of claims 11 to 18, The recess is formed in a stepped shape that rises one step from the end surface of the second holder. Energy storage module.

20. The storage module according to any one of claims 11 to 19, The recesses adjacent to each other are in communication with each other. Energy storage module.

21. A plurality of cylindrical electricity storage devices arranged in an array; a first holder that holds one end portion of the plurality of power storage devices and has a plurality of first housing portions made of a first material; Equipped with the first holder has a first support member between the adjacent power storage devices that supports the adjacent power storage devices and that is made of a second material; the second material has a property of being less likely to deform or melt when heated compared to the first material; a second holder having at least one second accommodating portion formed therein for accommodating the other end of at least one of the power storage devices; a heat exchange member facing the other surface of the second holder; and a thermally conductive material thermally connecting each of the at least one power storage device and the heat exchange member; Equipped with the second holder has at least one opening formed penetrating from the second accommodating portion toward the other side, and at least one peripheral wall formed on an edge of the opening on the other side surface of the second holder, the thermally conductive material is accommodated in the opening and on an inner peripheral side of the peripheral wall, The peripheral wall includes a notch that communicates the outer peripheral side and the inner peripheral side of the peripheral wall. Energy storage module.

22. The energy storage module according to claim 21, The notch extends in the height direction of the peripheral wall. Energy storage module.

23. The energy storage module according to claim 21 or 22, an inner circumferential surface of the peripheral wall is connected to an inner circumferential surface of the opening, The depth of the notch is the same as the height of the peripheral wall. Energy storage module.

24. The storage module according to any one of claims 21 to 23, a fixing portion that fixes the heat exchange member and the second holder, the at least one power storage device includes a plurality of power storage devices, the at least one second housing section includes a plurality of second housing sections that respectively house the plurality of power storage devices, the at least one peripheral wall comprises a plurality of peripheral walls; the plurality of peripheral walls include a first peripheral wall and a second peripheral wall that is farther from the fixing portion than the first peripheral wall, The amount of the cutout in the second peripheral wall is greater than the amount of the cutout in the first peripheral wall. Energy storage module.

25. The storage module according to any one of claims 21 to 24, a total volume of the thermally conductive material is greater than a sum of a volume in the at least one opening and a volume in the at least one peripheral wall; Energy storage module.

26. The storage module according to any one of claims 21 to 25, A tip of the at least one peripheral wall directly or indirectly contacts the heat exchange member. Energy storage module.

27. The storage module according to any one of claims 21 to 26, the peripheral wall includes a plurality of the notches, The notches are formed at approximately equal intervals in the circumferential direction of the peripheral wall. Energy storage module.

28. The energy storage module according to any one of claims 21 to 27, The notch is not formed in a portion of the peripheral wall that is closest to the adjacent peripheral wall in the circumferential direction of the peripheral wall. Energy storage module.

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