Electric power storage module

Abstract

This electric power storage module comprises: a plurality of electric power storage devices (22); a case (12) that contains the plurality of electric power storage devices (22); an opening (26c) that is provided to a portion of the case (12) for discharging gas from the interior of the case (12); a porous inside filter (36) that is located in the opening (26); a porous outside filter (38) that is located on the outside of the inside filter (36) with a gap therebetween; and a spacer (28) that is provided between the inside filter (36) and the outside filter (38), the spacer retaining the gap between the filters and having formed therein an opening through which the gas passes.

Description

Energy storage module

[0001] The present disclosure relates to an energy storage module having an opening in a case for discharging gas.

[0002] 2. Description of the Related Art Power storage modules including chargeable and dischargeable secondary batteries are used as power sources for portable devices, electric vehicles, and the like.

[0003] Large energy storage modules used as power sources for electric vehicles have multiple cell holders that hold multiple cells (element batteries). Each battery charges and discharges through a chemical reaction. This can sometimes generate gas inside the battery, and energy storage modules have a structure to exhaust the generated gas.

[0004] For example, Patent Document 1 describes a gas discharge mechanism for an electricity storage module.

[0005] Patent No. 6574987

[0006] The above-described gas discharge mechanism improves the reliability of the electricity storage module. However, with the recent trend toward higher capacity electricity storage devices, further improvements in the reliability of electricity storage modules are required.

[0007] The energy storage module according to the present disclosure includes a plurality of energy storage devices, a case that houses the plurality of energy storage devices, an opening provided in a part of the case for discharging internal gas, a porous inner filter arranged in the opening, a porous outer filter arranged outside the inner filter at a distance, and a spacer that is provided between the inner filter and the outer filter, maintains the distance between them, and has an opening formed therein through which gas can pass.

[0008] According to the present disclosure, the use of spacers increases the reliability of the filter.

[0009] 3 is a perspective view showing an energy storage module according to an embodiment of the present disclosure; FIG. 4 is a cross-sectional view showing the configuration of a gas discharge section provided on one end of a case according to an embodiment; FIG. 5 is an exploded perspective view showing the configuration of a gas discharge section provided on one end of a case according to an embodiment; FIG. 6 is an enlarged view of a spacer 28 of FIG. 2; FIG. 7 is an enlarged view of a retaining plate 34 of FIG. 2; FIG. 7 is a cross-sectional view showing the configuration of a gas discharge section provided on one end of a case according to an embodiment, at a position shifted from the axial center where a bolt is arranged; FIG. 8 is an exploded perspective view showing an energy storage module; FIG. 9 is an exploded perspective view showing an energy storage block; FIG. 10 is a perspective view showing a configuration of ribs in an energy storage module; FIG. 11 is an enlarged view of a main part showing the configuration of ribs in an energy storage module; FIG. 12 is a diagram for explaining holding of an energy storage device by a holder using ribs in an energy storage module, the left figure showing the state before insertion of the energy storage device, and the right figure showing the state after insertion; FIG. 13 is a plan view of a holder in an energy storage module as viewed from the axial direction, showing an example with one rib; FIG. 14 is a plan view of a holder in an energy storage module as viewed from the axial direction, showing an example with two ribs; FIG. 15 is a plan view of a holder in an energy storage module as viewed from the axial direction, showing an example with three ribs. FIG. 10 is a plan view of the holder in the energy storage module as seen from the axial direction, showing an example with four ribs; FIG. 11 is a diagram showing an example in which the shape of the ribs in the energy storage module is changed; FIG. 12 is a diagram showing a state in which an energy storage device is held by the holder in the energy storage module; FIG. 13 is a plan view of an example in which a notch is formed in the bottom surface of the holder in the energy storage module; FIG. 14 is a diagram showing an example in which a support is provided instead of a partition wall portion in the energy storage module; FIG. 15 is a diagram showing an example in which the side surface of the energy storage device in the energy storage module is covered with a sleeve, and a slit is formed in the sleeve. FIG. 16 is a diagram showing an example in which the side surface of the energy storage device in the energy storage module is covered with a sleeve, and a circular hole is formed as a recess in the sleeve.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following embodiments do not limit the present disclosure, and configurations formed by selectively combining multiple examples are also included in the present disclosure.

[0011] "External Configuration" Fig. 1 is a perspective view showing the external configuration of an energy storage module according to an embodiment. In this example, an energy storage module 10 houses a plurality of batteries as an example of an energy storage device in a rectangular prism-shaped case 12. A gas exhaust section 14 is provided on one end side of the case 12. Therefore, gas generated from the batteries inside the case 12 is exhausted to the outside from the gas exhaust section 14.

[0012] A pressure plate 34 is provided at one axial end (near side) of the gas discharge section 14. Four nuts 62 for fixing four fixed shafts 60 that pass through the inside of the case 12 are provided around the periphery of this pressure plate 34, and the case 12 is tightened from both axial ends by screwing the nuts 62 onto the ends of the fixed shafts 60. Note that the end face on the other end of the case 12 can be provided with a positive electrode in the center and a negative electrode on the periphery, for example, and the other ends of the fixed shafts 60 can be fixed appropriately to the end face on the other end of the case 12.

[0013] Here, a plurality of batteries are housed within the case 12, and for example, four storage blocks each containing ten batteries can be arranged in the axial direction. The case 12 may also house a circuit board 50 that mounts a circuit for controlling the charging and discharging of the batteries.

[0014] Four bolts 40 are provided around the periphery of the retaining plate 34 (inside the fixed shaft 60) to secure the various components of the gas discharge section 14 as described below.

[0015] The power storage module 10 of the present disclosure is used, for example, as a power source for electric motorcycles, assisted bicycles, electric wheelchairs, electric tricycles, electric carts, etc. However, the present disclosure does not specify the use of the power storage module 10, and the module can also be used as a power source for various electrical devices used outdoors, such as power tools.

[0016] "Configuration of Gas Discharge Section 14" FIG. 2 is a cross-sectional view showing the configuration of the gas discharge section 14 provided on one end side of the case 12, and FIG. 3 is an exploded perspective view showing the configuration of the gas discharge section 14.

[0017] The case 12 is open at both ends in the longitudinal direction, and a gas exhaust section 14 is provided so as to cover the opening at one end.

[0018] The gas exhaust section 14 has a cap 26 attached to the longitudinal end of the case 12. This cap 26 includes a donut-shaped outer edge 26a and a tubular section 26b extending from the outer peripheral edge of the outer edge 26a toward the portion of the case 12 that houses the battery 30 (referred to as the back side), and the back end of the tubular section 26b is fitted into the front axial tip of the case 12.

[0019] The cap 26 has an opening 26c formed in its center, into which a spacer 28 is fitted. The cap 26 also has eight holes (two at each corner), the four on the inside in the width direction being bolt holes 26d for inserting bolts 40 that secure the components of the gas exhaust section 14, and the four on the outside being shaft holes 26e for inserting fixing shafts 60 that secure both end portions of the case 12.

[0020] Here, opening 26c of cap 26 is octagonal, and the outer shape of spacer 28 fitted into this opening 26c is also octagonal. Spacer 28 is a combination of beam 28a extending radially from the center and annular beam 28b of a different radius, with opening 28c being formed between beam 28a and beam 28b.

[0021] An inner filter 36 is disposed on the case 12 side (rear side) of the spacer 28. This inner filter 36 covers the opening 26c of the cap 26. An outer filter 38 is disposed on the opposite side of the spacer 28 from the case 12 (referred to as the front side) so as to cover the opening 26c and the axially outer surface of the cap 26. The inner filter 36 is larger than the opening 26c. The inner filter 36 is smaller than the cap 26 and has bolt holes at its four corners but no axial hole. On the other hand, the outer filter 38 has substantially the same shape as the axial end surface of the cap 26 and has bolt holes and an axial hole at its four corners. Note that although porous materials are used for the inner filter 36 and the outer filter, any material may be used as long as it allows gas to pass through and removes predetermined solid matter.

[0022] The inner filter 36 and the outer filter 38 may be made of, for example, punched metal with numerous through holes formed in an aluminum plate. In this embodiment, two filters are provided: the inner filter 36 and the outer filter 38. This can suppress the release of solid matter, and a cooling effect due to heat transfer can also be expected for the gas passing through these filters.

[0023] Furthermore, in order to improve the filtering effect, the positions of the openings of the inner filter 36 and the outer filter 38 may be shifted relative to the gas flow direction, thereby increasing the filtering effect.

[0024] A retaining plate 34 is disposed axially outside the outer filter 38. The retaining plate 34 consists of a peripheral portion corresponding to the axial end face of the cap 26 and a central portion corresponding to the spacer 28 inside the peripheral portion. Four bolt holes and four shaft holes are provided at the four corners of the peripheral portion.

[0025] Furthermore, the central portion of the pressure plate 34 has substantially the same shape as the spacer 28. That is, the beams 34a and 34b of the pressure plate 34 correspond to the beams 28a and 28b of the spacer 28, and the opening 34c of the pressure plate 34 corresponds to the opening 28c of the spacer 28. Therefore, the resistance to gas flow of the spacer 28 and the pressure plate 34 can be kept small.

[0026] A protective partition 44 is disposed behind the inner filter 36 via four pipe-shaped partition spacers 42. The protective partition 44 has a shape corresponding to the shape of the inner filter 36, and is provided with bolt holes at the four corners.

[0027] Bolt holes are provided at the four corners of the retaining plate 34, outer filter 38, cap 26, inner filter 36, and protective partition wall 44 at the same positions in the longitudinal direction, and four partition wall spacers 42 are also provided at positions corresponding to the bolt holes. Four bolts 40 are inserted from the front side of the retaining plate 34 into the bolt holes of each component and pass through the partition wall spacer 42, with their tips protruding toward the back side of the protective partition wall 44. Nuts 46 are then screwed onto the tips of the four bolts 40, tightening the retaining plate 34 and protective partition wall 44 toward the components inside, thereby fixing the components together.

[0028] "Configuration of Spacer 28" Figure 4 is an enlarged view of the spacer 28 of Figure 2. As shown, the spacer 28 is composed of a combination of radial beams 28a and annular beams 28b. The two radial beams 28a-1 intersect across the entire spacer 28, forming an X-shape. Two annular beams 28b-1 and 28b-2 of different diameters are concentrically arranged. Furthermore, two radial beams 28a-2 (four in total) are provided on each side extending radially from the inner annular beam 28b-2 in the width direction, and two radial beams 28a-3 are provided extending upward and downward from the outer annular beam 28b-1 in the vertical direction. Each beam 28a, 28b is rectangular prism-shaped, with four openings 28c on the inside, eight openings 28c in the middle, and ten openings 28c between the outer cap 26 and the beam 28a. Furthermore, one surface of the spacer 28 abuts against the inner filter 36 in the axial direction, and the other surface abuts against the outer filter 38, thereby promoting heat dissipation from the inner filter 36 to the outer filter 38 via the spacer 28. Therefore, if the spacer 28 has a higher heat capacity than the inner filter 36 or the outer filter 38, heat dissipation from the inner filter 36 to the outer filter 38 is further promoted. In this case, it is preferable that the spacer 28, inner filter 36, and outer filter 38 are all made of metal from the perspective of thermal conductivity. Furthermore, the spacer 28 may be integral with at least one of the inner filter 36 and the outer filter 38.

[0029] "Configuration of the Retention Plate 34" Figure 5 is an enlarged view of the retention plate 34 of Figure 2. As shown, the retention plate 34 has a combination of radial beams 34a and annular beams 34b. That is, beams 34a-1, 34a-2, and 34a-3 are provided corresponding to the radial beams 28a-1, 28a-2, and 28a-3 of the spacer 28, and beams 34b-1 and 34b-2 are provided overlapping with the annular beams 28b-1 and 28b-2, thereby forming an opening 34c in the retention plate 34 that overlaps with the opening 28c in the spacer 28. In this way, the overlap of the opening and beams in the spacer 28 with the opening and beams in the retention plate 34 facilitates the flow of gas passing through the spacer 28 and the retention plate 34. Furthermore, the abutment of the spacer 28 and the retention plate 34 via the outer filter increases the rigidity of the gas exhaust section 14, facilitating heat transfer, primarily from the spacer 28 to the retention plate 34.

[0030] In addition, the retaining plate 34 has four bolt holes 34e for inserting bolts 40 and four shaft holes 34f for inserting fixed shafts 60 at the four corners of the peripheral portion 34d corresponding to the axial end face of the cap 26.

[0031] 6 is a cross-sectional view taken at a position offset from the axial center where the bolt 40 is disposed. As described above, the bolt 40 is disposed so as to penetrate the retaining plate 34, the outer filter 38, the outer edge portion 26 a of the cap 26, and the inner filter 36, and this bolt 40 further penetrates a partition spacer 42 disposed axially inside the inner filter 36, and is fixed with a nut 46 via a protective partition 44. That is, by tightening the nut 46 onto the end of the bolt 40, the protective partition 44 is pressed against the partition spacer 42, and the retaining plate 34, the outer filter 38, the outer edge portion 26 a of the cap 26, and the inner filter 36 are fastened together by the partition spacer 42 and the head of the bolt 40.

[0032] "Fixation by a Fixed Shaft" As shown in Figure 2, the retaining plate 34, outer filter 38, and cap 26 have axial holes at their four corners. A fixed shaft 60, shown by dashed lines in Figures 3 and 6, passes through these axial holes and is fastened to the retaining plate 34 by a nut 62. Although not shown, another axial hole is provided in the end face on the other end of the case 12, and the fixed shaft 60 passes through this axial hole at the other end, and a nut can be screwed onto the tip of the fixed shaft. In this way, by fastening the nut 62 to the end of the fixed shaft 60, the cap 26 can be fixed to the case 12. It is preferable that the fixed shaft 60 also pass through the holder that houses the internal battery 30.

[0033] 3 and 6, the case 12 is a hollow square cylinder that houses multiple batteries 30. In this example, the multiple batteries 30 are housed in a holder 24, which includes a main body 24a that supports each battery 30 individually and an end portion 24b that covers the axial end of the main body 24a, and the two are fastened together with bolts 24c. That is, after the batteries 30 are housed in the main body 24a, the end portion 24b is fixed to the main body 24a with the bolts 24c.

[0034] "Battery" The battery 30, which is an example of an energy storage device according to the present disclosure, is, for example, a cylindrical lithium-ion secondary battery, and has electrodes on both end surfaces as described above. The battery 30 is not limited to the present embodiment, and may be another energy storage device such as a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium polymer battery, or a capacitor. Furthermore, although the battery 30 is a cylindrical secondary battery, it is not limited to the present embodiment, and may also be a prismatic secondary battery.

[0035] "Materials of Each Component" Here, the case 12 is formed of a metal such as aluminum, which is strong and has excellent heat dissipation properties. The case 12 may also have grooves or protrusions formed along its longitudinal direction to improve strength. Furthermore, the surface of the metal case 12 may be coated with a laminate film, vinyl, or the like to insulate it. The cap 26 may be made of hard plastic or metal. The inner filter 36 and the outer filter 38 may be, for example, punched metal with numerous through-holes formed in an aluminum plate. The protective partition 44 may be made of a material with a higher melting point than the inner filter 36 and the outer filter 38. For example, it may be made of iron, stainless steel, or ceramics. The spacer 28 and the retaining plate 34 may be made of aluminum, iron, stainless steel, ceramics, or the like. The bolt 40 has a screw head on one end and is fastened to a nut 46 on the other end, which may be made of hard plastic or metal.

[0036] "Flow of generated gas" With this configuration, gas generated from the battery 30 is first diverted to the outside by the protective partition 44. This prevents the high-temperature gas from being blown directly onto the inner filter 36. The gas is then filtered by the two filters, the inner filter 36 and the outer filter 38, before being discharged to the outside of the case 12. This reduces the flow rate of the generated gas, and the filters remove solid matter before discharging it. Furthermore, the longer the path to discharge, the lower the temperature. This prevents the discharged gas from adversely affecting peripheral equipment.

[0037] Furthermore, the spacer 28 is positioned between the inner filter 36 and the outer filter 38, maintaining the distance between them. In particular, this prevents the inner filter 36 from expanding due to gas generated within the energy storage module pushing the inner filter 36 toward the outer filter 38. This also prevents one of the inner and outer filters 36, 38, from blocking the opening of the other filter due to the inner filter 36 expanding and approaching the outer filter 38. This effect is particularly pronounced when the opening of the inner filter 36 and the opening of the outer filter 38 are misaligned. Furthermore, the retaining plate 34 can suppress deformation due to expansion of the outer filter 38, and deformation of the inner filter 36 can be suppressed via the spacer 28.

[0038] "Structure for Fixing Battery to Holder" FIGS. 7 to 19 show examples of the structure of a battery and a holder that houses the battery.

[0039] "Electricity storage block" As shown in Fig. 7 and Fig. 8 , the electricity storage module 10 includes a plurality of electricity storage blocks 20. The electricity storage module 10 includes four electricity storage blocks 20 connected in series in the longitudinal direction, but this is not limited to this embodiment. Inter-block members 21 are provided between the electricity storage blocks 20. The inter-block members 21 include walls, buffer materials, etc. that separate the electricity storage blocks 20.

[0040] The power storage block 20 is a unit in which a plurality of batteries 30 are arranged in multiple tiers. In the power storage block 20, the plurality of batteries 30 are arranged so that the longitudinal direction (height direction, axial direction) of the batteries 30 is parallel to the first direction. Note that the power storage block 20 may have only a single tier of batteries 30, rather than multiple tiers. The power storage blocks 20 do not need to be arranged side by side in the first direction with the inter-block member 21 interposed therebetween, and may instead form a power storage module in which a plurality of power storage blocks 20 are arranged in a direction perpendicular to the first direction. In this case, each power storage block 20 may have a wall erected on the edge of the upper surface of the holder 31, and a lid may be provided that abuts the upper end of the wall and forms a duct portion between the power storage block 20 and the upper surface.

[0041] The electricity storage block 20 has a plurality of batteries 30 and holders 31, 32 that hold the respective batteries 30. As shown in Fig. 8, the holders 31, 32 have partition walls 35 that form storage recesses that store the plurality of batteries 30.

[0042] In the electricity storage block 20 of this embodiment, ten batteries 30 are arranged in a hexagonal lattice pattern (or in a bale-like pattern) in three rows of 3, 4, and 3 (three parallel units, which will be described later).

[0043] The electricity storage block 20 may be composed of a plurality of parallel units each having a plurality of batteries 30. Here, the parallel units may be configured by connecting the electrodes on both end faces of the batteries 30 in the first direction in parallel with lead plates. In the parallel units, the batteries 30 may be arranged in a row. Furthermore, adjacent parallel units may be arranged such that the polarities of the electrodes on the end faces of the batteries 30 are opposite to each other. Furthermore, in the electricity storage block 20, adjacent parallel units may be connected in series.

[0044] The power storage device of the present disclosure including the battery 30 is, for example, a cylindrical lithium-ion secondary battery, which has electrodes on both axial end surfaces as described above. The battery 30 is not limited to this embodiment and may be another secondary battery such as a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium polymer battery, or a capacitor. Furthermore, although the battery 30 is a cylindrical secondary battery, it is not limited to this embodiment and may also be a prismatic secondary battery.

[0045] The battery 30 may include an electrode assembly in which strip-shaped positive and negative electrodes are wound facing each other with a separator interposed therebetween; a can (exterior body) that houses the electrode assembly together with an electrolyte and has a cylindrical portion and a bottom that closes one end of the cylindrical portion; and a sealing member that closes the opening at the other end of the can. The sealing member may be electrically connected to one of the positive and negative electrodes via a lead or the like. The can may be electrically connected to the other of the positive and negative electrodes via a lead or the like. If the sealing member and the can have opposite polarities, an insulating member such as a gasket may be interposed between the sealing member and the opening of the can. A groove 30A may be formed on the outer peripheral surface of the can in the region between the electrode assembly and the sealing member. Furthermore, the portion of the inner peripheral surface of the can where the groove 30A is formed may protrude inward of the can. The groove 30A is referred to as a recess. A sealing member may be placed inside the can on the protrusion formed by the groove, and the end of the can opening may be bent inward in the radial direction of the can. This end and protrusion allow the closure member to be fixed in the first direction (axial direction, battery height direction). If a through-hole is provided in the closure member to accommodate a terminal connected to one electrode of the electrode assembly, the outer edge of the closure member may be welded to the opening of the can to seal the opening. In this case, a recess may be formed on the outer surface of the can for engaging with the rib 70. The exterior body including the can may be made of a conductive material such as metal when electrically connected to the electrode assembly, or may be made of an insulating material such as resin when not electrically connected to the electrode assembly. The battery 30 may have an exhaust port at at least one end in the first direction. This configuration allows gas accumulated within the battery 30 to be discharged to the outside of the battery 30 and the energy storage block 20 via the exhaust port. The exhaust port may be an irreversible valve that opens by breaking a marking, or a reversible valve that forms an exhaust path by further compressing a compressed elastic body with gas pressure. Furthermore, exhaust ports may be formed at both ends of the battery 30 in the first direction.

[0046] As shown in FIG. 8 , the holders 31 and 32 are divided into two parts at approximately the center of the longitudinal direction (first direction, axial direction, height direction) of the batteries 30. The holder 31 holds one side of the multiple batteries 30 arranged in a hexagonal lattice pattern. The holder 31 has a holding portion 31A integrally formed with a cylindrical housing portion into which one longitudinal end of each of the arranged batteries 30 fits, and a sidewall 31B formed along the outer periphery of the arranged batteries 30. The holding portion 31A of the holder 31 and the holding portion 32A of the holder 32 each have multiple openings formed therethrough in the first direction (the longitudinal direction of the batteries). Battery current is collected and exhaust air is discharged through these openings. Alternatively, instead of using the holder 32, the holder 31 may cover both axial ends of the outer periphery of the batteries 30, and the insertion opening of the housing portion of the holder 31 may be covered with a plate material such as a lid. In this case, the plate material may be fastened to the corners of the holder 31 with screws or the like.

[0047] A hole 32H is provided in the side wall 31B of the holder 31, penetrating in the longitudinal direction. The fixed shaft 60 is inserted into the hole 32H and engages with the inter-block member 21. Two holes 32H are provided, but this is not limited to this embodiment and the number of holes 32H may be determined according to the number of fixed shafts 60. The holder 31 may also have a liquid injection hole 31T through which potting material is poured after the batteries 30 are housed and assembled in the holders 31, 32.

[0048] The holder 32 has the same configuration as the holder 31, and therefore a description thereof will be omitted. An engaging portion formed at the other longitudinal end of the side wall 31B of the holder 31 engages with an engaging portion formed at one longitudinal end of the side wall 32B of the holder 32, thereby connecting the holders 31 and 32.

[0049] The partition wall 35 is formed to fill the gaps between the batteries 30 arranged in a hexagonal lattice pattern as described above. The partition wall 35 is formed from a material with some elasticity, such as hard plastic or potting material, but is not limited to this embodiment. The partition wall 35 may contain a heat-absorbing material, such as aluminum hydroxide. In this embodiment, the partition wall 35 is integral with the holder 31, but may be a separate body. As described below, ribs 70 may be formed in the partition wall 35, and the ribs 70 must have relatively high elasticity. Therefore, the partition wall 35 is preferably formed from a plastic material with relatively high elasticity. One example of such a plastic material is polycarbonate (PC).

[0050] 7 and 8, one or both of the holders 31 and 32 have ribs 70 on the inner surface of the housing portion for the battery 30. Note that, although an example in which the ribs 70 are provided on the holder 31 will be described below, the ribs 70 may also be provided on the inner wall surface of the holder 32, or both the holders 31 and 32 may have ribs 70.

[0051] 9A and 9B show the configuration of the rib 70 in the holder 31, with Fig. 9A being a perspective view and Fig. 9B being an enlarged view of a main portion. The holder 31 is integrally constructed including the partition wall 35, and has a housing portion 72, which is a cylindrical hole that houses one end of the battery 30 in the first direction. A rib 70 is formed on the inner wall 72A of this housing portion 72. The rib 70 is a ridge-like protrusion that extends in the axial direction of the housing portion 72, extending partway in the axial direction from the bottom of the housing portion 72 (towards the axial center of the battery 30).

[0052] In this example, only one rib 70 is provided and pressed against the opposite side of the partition wall 35, but multiple ribs 70 may be provided and the battery 30 may be held in the housing portion 72 by the multiple ribs 70. In particular, by providing three or more ribs 70 around the outer periphery of the battery 30, the battery 30 can be held more stably.

[0053] 10 is a diagram illustrating how the holder 31 uses the rib 70 to hold the battery 30. The left image shows the battery 30 before insertion, and the right image shows the battery 30 after insertion. The rib 70 is a ridge-like protrusion as shown in FIG. 5, and one rib is provided on the inner wall 72A of the storage section 72.

[0054] As shown in FIG. 6 , the battery 30 has an annular groove 30A near one end. That is, the groove 30A extends circumferentially on the side of the battery 30 between the body 30B, which forms the main body of the battery 30, and the head 30C, where the electrodes and other components are formed. The groove 30A is formed in the battery 30 by, for example, using the battery's outer tube (case) as a cylindrical container with an open end, accommodating the electrode assembly and electrolyte therein, and then crimping the open end of the tube to secure a sealing material over the groove 30A. The diameter of the housing portion 72, measured from the inner end of the rib 70, is smaller than the diameters of the body 30B and head 30C of the battery 30. This difference in diameter is within the range of elastic deformation of the rib 70 (including the range of deformation of the inner wall 72A). Therefore, the battery 30 can be inserted into the housing portion 72 by displacing the rib 70.

[0055] By pressing the battery 30 in the axial direction, the rib 70 is pressed against the head 30C and body 30B and elastically recesses, causing the head 30C and body 30B to be inserted (or press-fit) into the housing 72. When the battery 30 is inserted into the housing 72 to a predetermined depth, the portion of the rib 70 facing the groove 30A bulges into the groove 30A. That is, the rib 70 is pressed outward at the portion of the rib 70 facing the head 30C and body 30B, but there is no resistance from the battery 30 at the portion facing the groove 30A, so the rib 70 bulges back toward its original position, forming the bulge 70A. Note that at the groove 30A-side ends of the head 30C and body 30B, the rib 70 moves slightly toward the groove 30A, which may increase the size of the bulge 70A.

[0056] As described above, in this embodiment, ribs 70, which are ridge-like protrusions, are formed on the inner wall 72A of the storage section 72 of the holder 31 that accommodates the battery 30. The battery 30 is inserted while the ribs 70 are deformed. Therefore, no special operation is required when inserting the battery 30. When insertion is complete, the ribs 70 bulge toward the groove 30A, forming the bulged portions 70A. This reliably prevents axial movement of the battery 30. By integrally forming the ribs 70 with the holder 31, no attachment operation is required and they can be formed using a standard molding process. This eliminates the need for adhesives, reduces the number of parts, and improves workability when assembling the energy storage module. In particular, the shape of the bulged portions 70A is utilized to generate resistance against impacts, thereby reliably holding the battery 30. Furthermore, if the dimension of the rib 70 in the first direction is larger than the maximum dimension of the groove 30A in the first direction, the rib 70 can hold portions other than the groove 30A, thereby more firmly holding the battery 30.

[0057] The example of FIG. 10 shows a case where three ribs 70 are provided, and therefore the rib 70 is shown on only one of the inner walls 72A of the two accommodating portions 72 shown in the figure.

[0058] 11 to 14 are plan views of the holder 31 as viewed from the axial direction, with Fig. 11 showing an example with one rib 70, Fig. 12 showing two ribs 70, Fig. 13 showing three ribs 70, and Fig. 14 showing four ribs 70. In the case of one rib, the rib may be provided at any position in the circumferential direction of the housing portion 72, but from a manufacturing standpoint, it is preferable to provide ribs 70 of the same shape at the same position in all of the housing portions 72. In the cases of Figs. 12 to 14, it is preferable that the multiple ribs 70 provided in one housing portion 72 be equally spaced in the circumferential direction.

[0059] "Rib Shape" Figure 15 is a diagram showing an example in which the shape of the rib 70 has been changed. In this example, the rib 70 is enlarged in the circumferential direction. In particular, when viewed from the radial direction of the housing section 72, the circumferential dimension of the rib 70 is longer than the dimension in the first direction. This configuration can prevent the battery 30 from tilting around the radial axis within the housing section 72.

[0060] "Retention Structure" Figure 16 is a diagram showing the state in which the battery 30 is held by the holders 31, 32. In this example, a groove 30A is provided on the holder 31 side of the battery 30, and therefore ribs 70 are provided on the inner wall 72A of the storage section 72 of the holder 31. In this example, ribs 70 are also provided on the inner wall 72A on both sides of the storage section 72.

[0061] "Explanation of Modifications" <Example of Providing Cutouts> Fig. 17 is a plan view of an example in which cutouts are formed in the bottom surface of the holder 31. In this example, six cutouts 80 are provided in the peripheral portion of the bottom 72B of one of the accommodation sections 72 that contacts the inner wall 72A. These cutouts 80 are larger than the ribs 70 and are positioned at equal intervals in the circumferential direction. Furthermore, ribs 70 are provided at positions corresponding to every other three of the six cutouts 80. Therefore, the bottom surface side ends of the ribs 70 are positioned within the cutouts 80.

[0062] By providing such a notch 80, the inner wall 72A of the storage section 72 on which the rib 70 is provided can be more easily elastically deformed, making it easier to insert the battery 30 and more reliably pressing the rib 70 against the outer peripheral surface of the battery 30. Note that this notch 80 may be an opening that penetrates in the first direction or a thinner portion at the bottom of the storage section 72 than other portions.

[0063] <Example in which Supports are Provided> Figure 18 is a diagram showing an example in which support posts 90 are provided instead of the partition wall 35. That is, the holder 31 has ten storage sections 72 that accommodate batteries 30. Of the ten storage sections 72, the two innermost storage sections 72 are each defined by six support posts 90 and the top surface of the holder 31. Eight storage sections 72 located around the two storage sections 72 are each defined by the side wall 31B of the holder 31, the top surface of the holder 31, and two support posts 90. Three ribs 70 are located around each storage section 72. Therefore, some of the ribs 70 are provided on the inner surface of the side wall 31B, and the remaining ribs 70 are provided on the side surfaces of the support posts 90.

[0064] With this configuration, as in the above-described embodiment, the batteries 30 can be reliably held by the bulging portions 70A of the ribs 70. The use of the support posts 90 reduces the use of the partition wall portions 35, making it easier to narrow the distance between a pair of adjacent batteries 30.

[0065] "Example of forming a hole in the sleeve of the battery 30" Figures 19A and 19B are figures showing an example in which the side of the battery 30 is covered with a sleeve 100 and a hole is formed in this sleeve 100, (A) showing an example in which a slit 102 is formed as a recess, and (B) showing an example in which a round hole 104 is formed as a recess.

[0066] In this way, in this example, a sleeve 100 is provided that covers the outer periphery of the battery 30 (particularly the can). This sleeve 100 is made of plastic or metal such as aluminum, and is capable of protecting the battery 30. Typically, a thin plastic or aluminum plate sized to fit the battery 30 is wrapped around and adhered to the side of the battery 30.

[0067] 19A , a plurality of axially extending slits 102 are formed in a row in the circumferential direction at positions corresponding to the ribs 70 of the housing portion 72 of the sleeve 100. The width of the slits 102 can be set smaller than the width of the ribs 70. In this case, a portion of the ribs 70 bulges toward the inside of the slits 102. Alternatively, the width of the slits 102 may be larger than the width of the ribs 70. In this case, a portion of the ribs 70 bulges toward the inside of the slits 102.

[0068] That is, the portion of the rib 70 facing the slit 102 bulges toward the outer surface of the battery 30 by the thickness of the sleeve 100, forming a bulge 70A here that engages (or fits) with the end of the slit 102. Therefore, the engagement (or fit) of the bulge 70A with the slit 102 allows the battery 30 to be held in the holder 31.

[0069] Furthermore, by setting the battery 30 where the slit 102 is formed in a recessed location, the beam between the slits 102 can move. For example, the slits 102 can be provided at a position corresponding to the groove 30A of the battery 30. In this case, the axial length of the slit 102 may be greater or less than the axial width of the groove 30A. If the axial length is greater, both ends of the groove 30A restrict the axial direction of the bulging portion 70A of the rib 70; if the axial length is smaller, both ends of the slit 102 restrict the axial direction of the bulging portion 70A.

[0070] Furthermore, the groove 30A may not be present at the position of the battery 30 corresponding to the slit 102, and the diameter of the end of the battery 30 may be smaller. With this configuration, the slit 102 can also restrict the bulge 70A, and the rib 70 can restrict the vertical movement of the battery 30.

[0071] 19B, round holes 104 are provided instead of the slits 102. With this configuration, a portion of the rib 70 bulges toward the round holes 104, forming bulging portions 70A therein, thereby achieving the same effect as the slits 102.

[0072] The holes formed in the sleeve 100 are not limited to the slits 102 and the round holes 104, and may have any shape as long as they can accommodate the bulging portions 70A. Also, the sleeve may have depressions formed therein instead of through holes.

[0073] With this configuration, when a battery 30 with a sleeve 100 is inserted into the housing section 72, not only does the rib 70 deform, but the area where the slit 102 and round hole 104 are provided also deforms. This increases the force holding the rib 70 in place, increasing resistance to impact.

[0074] 7 to 19B are described below. The energy storage module according to the present disclosure includes: a plurality of cylindrical energy storage devices each having a recess on a side surface; and a holder having a housing portion formed with at least one hole for housing one axial end of the plurality of energy storage devices, wherein a rib protruding toward the recess is formed inside the housing portion, and the rib is elastically deformable and fits into and engages with the recess.

[0075] The power storage module according to the present disclosure can be used as a power source for electric vehicles and the like.

[0076] 10 Energy storage module, 12 Case, 14 Gas exhaust section, 20 Energy storage block, 21 Inter-block member, 24 Holder, 26 Cap, 28 Spacer, 30 Battery (energy storage device), 31, 32 Holder, 35 Partition section, 36 Inner filter, 38 Outer filter, 34 Retaining plate, 40 Bolt, 42 Partition spacer, 44 Protective partition, 50 Circuit board, 60 Fixed shaft, 70 Rib, 70A Bulging section, 72 Storage section, 80 Notch, 90 Support, 100 Sleeve, 102 Slit, 104 Round hole.

Claims

1. An energy storage module comprising: a plurality of energy storage devices; a case that houses the plurality of energy storage devices; an opening provided in a part of the case for discharging gas inside the case; a porous inner filter arranged in the opening; a porous outer filter arranged outside the inner filter at a distance; and a spacer that is provided between the inner filter and the outer filter, maintaining the distance between them and having an opening formed therein through which gas can pass.

2. The energy storage module according to claim 1, wherein the opening of the spacer is larger than the openings of the inner filter and the outer filter.

3. An energy storage module according to claim 1, wherein the inner filter, the outer filter, and the spacer are made of metal, one surface of the spacer abuts against the inner filter, and the other surface of the spacer opposite to the one surface abuts against the outer filter.

4. The energy storage module according to any one of claims 1 to 3, further comprising a retaining plate provided outside the outer filter and covering the outer filter.

5. The energy storage module according to claim 4, wherein the retaining plate has an opening that overlaps with the opening of the spacer.

6. An energy storage module according to claim 4, wherein the spacer has a beam that defines the opening, the retaining plate has a beam that defines the opening, and the beam of the spacer and the beam of the retaining plate overlap.

7. The energy storage module according to claim 4, wherein the inner filter, the spacer, the outer filter, and the retaining plate are fixed to the case by bolts.

8. An energy storage module as claimed in claim 1, wherein the plurality of energy storage devices are cylindrical and have recesses on their sides, the case is housed in a holder having a housing section with at least one hole formed therein for housing one axial end of the plurality of energy storage devices, and a rib is formed inside the housing section and protrudes towards the recess, and the rib is elastically deformable and fits into and engages with the recess.

9. An energy storage module according to claim 8, wherein the ribs are ridge-shaped extending in the axial direction of the energy storage device, cross the recesses in the axial direction, and the portions facing the recesses bulge toward the recesses.

10. An energy storage module according to claim 8, wherein the accommodation portion of the holder is composed of a plurality of holes, the ribs are formed on the inner surfaces of the plurality of holes, and each of the plurality of energy storage devices is accommodated in one of the plurality of holes.

11. An energy storage module according to claim 8, wherein the accommodation portion of the holder has at least one support pillar extending in the axial direction, and each of the plurality of energy storage devices abuts against the inner surface of the hole and a side surface of the at least one support pillar.

12. The energy storage module according to claim 11, wherein the rib is formed on a side surface of the at least one support column.

13. An energy storage module according to claim 8, wherein an opening, a notch, or a thin-walled portion that overlaps with the rib in the axial direction is formed on the bottom surface of the housing portion.

14. The energy storage module according to claim 8, further comprising a holder having a housing portion that houses the other ends of the plurality of energy storage devices in the axial direction.

15. An energy storage module according to claim 8, wherein the recess is a groove extending circumferentially around the side surface of the energy storage device.

16. An energy storage module according to claim 8, wherein the recessed portion is a plurality of holes provided discretely in the circumferential direction on the side surface of the energy storage device.

17. An energy storage module according to claim 8, wherein the energy storage device comprises: an electrode body including a positive electrode and a negative electrode; an exterior body that houses the electrode body and has a tubular portion, a bottom that closes one end of the tubular portion, and an opening formed in the other end of the tubular portion; and a sealing member that closes the opening.

18. An energy storage module according to claim 17, wherein the energy storage device further comprises a cylindrical sleeve covering the outer circumferential surface of the exterior body, and a through-hole or depression constituting the recess is formed in the outer circumferential surface of the sleeve.

19. An energy storage module according to claim 17, wherein a groove extending in the circumferential direction is formed on the outer peripheral surface of the exterior body and disposed between the sealing member and the electrode body, and the groove is the recess.