Power storage device

Abstract

A power storage device according to the present invention comprises: a plurality of power storage elements arrayed in a first direction; an end plate disposed at an end part in the first direction of the plurality of power storage elements; and a side plate extending in the first direction and connected to the end plate. The side plate includes a first portion extending in the first direction, a second portion extending from the first portion so as to cover the end plate and fixed to the end plate, and a third portion which extends from the second portion in the first direction so as to lie along an installation surface of the power storage device, and is fixed to the installation surface.

Description

Power storage device

[0001] The present invention relates to an electricity storage device.

[0002] The energy storage device of Patent Document 1 includes a plurality of energy storage elements, a pair of end plates, and a pair of side plates. The plurality of energy storage elements are aligned in one direction, with end plates disposed at both ends. The pair of side plates are arranged to sandwich the energy storage elements in the direction in which the energy storage elements are aligned. Both ends of each side plate are connected to the end plates. This allows the plurality of energy storage elements to be fixed by the side plates and end plates. In this energy storage device, portions of the end plates extend to the installation surface, and the extended portions are fixed to the installation surface with bolts.

[0003] Japanese Patent Application Laid-Open No. 2020-30915

[0004] Energy storage elements expand during repeated charging and discharging. Therefore, when an energy storage device is in use, the expansion of the energy storage elements in the arrangement direction exerts a force on the end plates. In the energy storage device of Patent Document 1, the end plates are fixed to the installation surface. Therefore, if the end plates are deformed due to the expansion of the energy storage elements, a force may also act on the fixed portions between the end plates and the installation surface, potentially damaging the bolts and otherwise impairing the installation. The present invention aims to provide an energy storage device that can prevent the expansion of the energy storage elements from impairing the installation.

[0005] The storage element of the present invention comprises a plurality of storage elements arranged in a first direction, an end plate arranged at an end of the plurality of storage elements in the first direction, and a side plate arranged at an end of the plurality of storage elements in a second direction intersecting the first direction, wherein the end plate includes an end plate connection portion connected to the side plate, and the side plate comprises a first portion extending in the first direction, a second portion extending from the first portion in a second direction intersecting the first direction and connected to the end plate connection portion, and a third portion extending from the second portion in the first direction along an installation surface of the storage device and fixed to the installation surface.

[0006] According to the electricity storage device of the present invention, it is possible to prevent the expansion of the electricity storage elements from interfering with the installation state.

[0007] Fig. 1 is a perspective view showing the appearance of an electricity storage device according to one embodiment of the present invention. Fig. 2 is a perspective view of an end plate used in the electricity storage device of Fig. 1. Fig. 3 is a perspective view of a side plate used in the electricity storage device of Fig. 1. Fig. 4 is a front view of the electricity storage device of Fig. 1 as seen from the front. Fig. 5 is a front view of another example of an electricity storage device as seen from the front.

[0008] First, an overview of the power storage device disclosed in this specification will be described.

[0009] (1) An energy storage device according to one embodiment of the present invention comprises a plurality of energy storage elements arranged in a first direction, end plates arranged at ends of the plurality of energy storage elements in the first direction, and side plates arranged at ends of the plurality of energy storage elements in a second direction intersecting the first direction, wherein the end plates include end plate connection portions connected to the side plates, and the side plates comprise a first portion extending in the first direction, a second portion extending from the first portion in the second direction and connected to the end plate connection portion, and a third portion extending from the second portion in the first direction along an installation surface of the energy storage device and fixed to the installation surface.

[0010] In the energy storage device according to one embodiment of the present invention, the third section extending from the side plate is fixed to the installation surface with, for example, a bolt, rather than the end plate. This prevents the force received by the end plate from acting directly on the third section. This prevents damage to the bolts that fix the third section to the installation surface. In other words, it is possible to prevent the installation state of the energy storage device from being affected when the energy storage element expands.

[0011] (2) In the energy storage device described above in (1), the side plate may be formed from a single plate material, and the first portion, the second portion, and the third portion may be formed by bending the plate material.

[0012] According to the electricity storage device described in (2) above, the side plates can be easily manufactured.

[0013] (3) In the energy storage device described in (1) or (2) above, the third portion may have an elongated hole through which a fixing member for fixing the installation surface and the third portion is inserted.

[0014] According to the energy storage device described in (3) above, when the fixing member is inserted into the elongated hole in the third portion to fix the third portion to the installation surface, the position of the fixing member can be adjusted within the elongated hole. Therefore, even if the dimensional tolerance of the fixing position of the third portion becomes large, the tolerance can be absorbed and the third portion can be fixed to the installation surface.

[0015] (4) In the power storage device according to any one of (1) to (3) above, the third portion may be provided near the first portion in the second direction.

[0016] Since the energy storage element expands particularly near the center, the center of the end plate is particularly subjected to force when the energy storage element expands. According to the energy storage device described in (4) above, by locating the third portion near the first portion, i.e., away from the center of the end plate, the end plate is less susceptible to the force when the energy storage element expands. This reduces the effect of the expansion of the energy storage element on the strength of the fixation between the third portion and the installation surface.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the end plate may have a raised portion arranged adjacent to the end plate connection portion, and the thickness of the raised portion may be thicker than the thickness of the end plate connection portion in the first direction.

[0018] According to the energy storage device described in (5) above, the thickness of the end plate in the first direction is increased at the portion that receives the force caused by the expansion of the energy storage element, and deformation of the end plate can be suppressed.

[0019] 1. Embodiment of the Energy Storage Device 100 An embodiment of the energy storage device 100 according to the present invention will be described below with reference to the drawings. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiment and its modified examples are merely examples and are not intended to limit the present invention. Each figure is a schematic diagram, and dimensions and the like are not necessarily depicted precisely. In each figure, the same or similar components are designated by the same reference numerals.

[0020] In the following description and in the drawings, for convenience of explanation, the directions shown in FIGS. 1 to 4 will be used. The direction in which the energy storage elements 1 are lined up, or the direction in which a pair of end plates face each other, is defined as the front-rear direction. The direction in which a pair of external terminals of the energy storage elements are lined up, or the direction in which a pair of side plates face each other, is defined as the left-right direction. The direction in which the external terminals of the energy storage elements protrude, or the direction intersecting the front-rear direction and the left-right direction, is defined as the up-down direction. These front-rear direction, left-right direction, and up-down direction intersect with each other (orthogonal in this embodiment). However, these directions are set for convenience of explanation and do not limit the present invention. In the following description, the front-rear direction will also be referred to as the first direction. The left-right direction will also be referred to as the second direction. The up-down direction will also be referred to as the third direction.

[0021] Expressions indicating a relative direction or attitude, such as "parallel" and "orthogonal," also include cases where the direction or attitude is not strictly that. When two directions are orthogonal, it does not only mean that the two directions are completely orthogonal, but also means that the two directions are substantially orthogonal, or that the angles are shifted from 90 degrees by a few degrees.

[0022] 2. Overview of Energy Storage Device 100 FIG. 1 is a perspective view of the energy storage device 100 of this embodiment. As shown in FIG. 1 , the energy storage device 100 includes a plurality of energy storage elements 1 arranged in a front-to-rear direction (first direction), end plates 2 arranged at both ends of the energy storage elements 1 in the front-to-rear direction, and side plates 3 sandwiching the plurality of energy storage elements 1 from the left-to-right direction (second direction) perpendicular to the front-to-rear direction. That is, the energy storage device 100 includes end plates 2 arranged at both ends of the plurality of energy storage elements 1 in the arrangement direction of the plurality of energy storage elements 1, and side plates 3 sandwiching the plurality of energy storage elements 1 in a direction perpendicular to the arrangement direction of the plurality of energy storage elements 1. In addition to these components, the energy storage device 100 also includes spacers arranged next to the energy storage elements 1, end spacers arranged next to the end plates, bus bars connecting adjacent energy storage elements 1, and insulating members arranged next to the side plates, but detailed description thereof will be omitted. Each of these members will be described below.

[0023] 3. Energy Storage Element Each energy storage element 1 is configured by a primary battery, a secondary battery, a capacitor, or the like. In this embodiment, an energy storage element 1 configured by a chargeable and dischargeable non-aqueous electrolyte secondary battery is exemplified. More specifically, each energy storage element 1 is a lithium ion secondary battery that utilizes electron transfer that occurs with the transfer of lithium ions.

[0024] Each energy storage element 1 has an electrode body, a case 11 that houses the electrode body together with an electrolyte, and a pair of external terminals 12, at least a portion of which protrudes in the vertical direction outside the case 11. A pair of external terminals 12 is provided in the left-right direction, which is the width direction of the energy storage element 1.

[0025] The case 11 is formed in a rectangular parallelepiped shape and includes a case body with an opening on the top in the vertical direction, and a plate-like lid that closes the opening of the case body. A pair of external terminals 12 is disposed near each of the left and right ends of the lid. The case 11 is formed in a flat rectangular parallelepiped shape that is long in the left and right directions and long in the up and down directions, but short in the front-to-back direction. The energy storage elements 1 are lined up in the front-to-back direction so that their front-to-back faces face each other.

[0026] 2 is a perspective view of an end plate. As shown in Fig. 1, the end plates 2 are arranged on the front and rear sides of the energy storage elements 1 in the front-rear direction, but since the two end plates are the same, the end plate 2 in contact with the energy storage element 1 arranged on the front side will be described with reference to Fig. 2.

[0027] As shown in Fig. 2, the end plate 2 is formed in the shape of a flat rectangular parallelepiped with a short length in the front-to-rear direction. The length of the end plate 2 in the left-to-right direction is approximately the same as the length of the energy storage element 1 in the left-to-right direction. As shown in Fig. 1, the length of the end plate 2 in the up-to-down direction is shorter than the length of the energy storage element 1 in the up-to-down direction. The rear surface of the end plate 2 in the front-to-rear direction is formed flat and faces the energy storage element 1. The surface of the end plate facing the energy storage element is also formed flat.

[0028] A pair of end plate connection portions 23 are formed on both the left and right sides of the end plate 2. The end plate connection portions 23 are the locations to which the side plates 3 are connected. Each end plate connection portion 23 has a plurality of (three in this embodiment) screw holes 231 aligned in the vertical direction. The screw holes 231 are also referred to as end fixing portions that are fixed to the side plates 3.

[0029] A raised portion 21 having a rectangular shape in front view is formed between the pair of end plate connection portions 23. In other words, the raised portion 21 is formed on the front side of the end plate 2 in a region including the center of the surface in the left-right direction. In the first direction, the thickness of the raised portion 21 is greater than the thickness of the end plate connection portion 23. The raised portion 21 extends from the lower end to the upper end of the end plate 2 in the up-down direction. On both sides of the raised portion 21 in the left-right direction, end plate connection portions 23 with flat surfaces are formed via steps 22. A second portion 32 of the side plate 3, described below, can be placed in the recess created by the steps 22. The end plate 2 can be formed of metal. The raised portion 21 increases the thickness of the end plate in the front-to-rear direction, thereby improving the strength of the end plate.

[0030] 5. Side Plates In this embodiment, a pair of side plates 3 are used, but since they have a symmetrical shape, only the side plate 3 disposed on the left side of the energy storage device 100 will be described. Fig. 3 is a perspective view of the side plate disposed on the left side.

[0031] 3, the side plate 3 is formed by bending a single metal plate and includes a rectangular first portion 31 extending in the front-rear direction, rectangular second portions 32 extending in the left-right direction and connected to both ends of the first portion 31 in the front-rear direction, and a third portion 33 connected to the lower end in the up-down direction of each second portion 32. A fourth portion 34 and a fifth portion 35 extending to the right in the left-right direction are connected to both ends of the first portion 31 in the up-down direction.

[0032] The first portion 31 is a plate-like portion arranged in the left-right direction of the plurality of energy storage devices 1, and has a plurality of through holes 311 extending in the up-down direction formed at predetermined intervals in the front-rear direction. Cooling air can be applied to the energy storage devices 1 through the through holes 311.

[0033] The second portion 32 is connected to the front-rear end of the first portion 31. That is, the second portion 32 is a plate-shaped portion bent in the left-right direction (second direction) from the end of the first portion 31 and extending in the left-right direction. The second portion 32 is connected to the end plate connection portion 23 of the end plate 2. The second portion 32 is formed in a shape that conforms to the surface of the end plate connection portion 23 of the end plate 2 and is fixed so as to contact the end plate connection portion 23. Therefore, multiple (three in this embodiment) through holes 321 aligned in the vertical direction are formed in the left-right end of the second portion 32. These through holes 321 are formed at positions corresponding to the screw holes 231 of the end plate 2. The through holes 321 (first side fixing portions) of the side plate 3 and the screw holes (end fixing portions) 231 of the end plate 2 are fixed by bolts.

[0034] The vertical length of the second portion 32 is shorter than the vertical length of the first portion 31. The vertical length of the second portion 32 is approximately the same as the vertical length of the end plate 2. The vertical lower end of the second portion 32 is located at approximately the same height as the vertical lower end of the first portion 31.

[0035] The third portion 33 is a plate-like portion that is bent in the front-rear direction from the lower end of the second portion 32 in the up-down direction and extends in the front-rear direction (first direction). The third portion 33 extends along an installation surface 8 on which the energy storage device 100 is installed. As shown in FIG. 3( a), a circular through-hole 331 is formed in the third portion 33, and a bolt (fixing member) is inserted through this through-hole 331. The through-hole 331 is also referred to as a second side fixing portion that is fixed to the installation surface 8. The installation surface 8 is a surface on which the energy storage device 100 is placed and fixed. Examples of the installation surface 8 include the floor surface of a power storage device case that houses the energy storage device 100 and a shelf board of a rack on which the energy storage device is placed.

[0036] The fourth portion 34 is a plate-shaped portion that extends along the upper end of the first portion 31 in the vertical direction, is bent at a right angle from the upper end, and extends in the left-right direction. The fourth portion 34 has a short length in the left-right direction, and is in contact with the upper surfaces of the plurality of energy storage elements 1 in the vertical direction. The fifth portion 35 is a plate-shaped portion that extends along the lower end of the first portion 31 in the vertical direction, is bent at a right angle from the lower end, and extends in the left-right direction. The fifth portion 35 has a short length in the left-right direction, and is in contact with the lower surfaces of the plurality of energy storage elements 1 in the vertical direction.

[0037] 6. Assembly of the Energy Storage Device 100 Next, a method for assembling the energy storage device 100 configured as described above will be described. First, the multiple energy storage devices 1 are aligned in the front-to-rear direction. Next, end plates 2 are placed on both ends of the multiple energy storage devices 1 in the front-to-rear direction. Next, each side plate 3 is attached to both ends of the multiple energy storage devices 1 in the left-to-right direction. Specifically, the multiple energy storage devices 1 are placed between the fourth portion 34 and the fifth portion 35 of the side plate 3. Insulating members 5 are placed between the fourth portion 34 and the multiple energy storage devices 1 and between the fifth portion 35 and the multiple energy storage devices 1. In this manner, the multiple energy storage devices 1 are supported from above and below in the vertical direction by the side plate 3. At this time, the second portion 32 of each side plate 3 is stacked on the end plate connection portion 23 of the end plate 2. Next, as shown in FIG. 4 , bolts 51 are inserted into the through holes 321 of the second portions 32 and screwed into the threaded holes 231 of the end plate 2. In this way, the side plates 3 are fixed to the end plates 2. As a result, the plurality of energy storage elements 1 are integrally fixed by the end plates 2 and the side plates 3. Adjacent energy storage elements 1 are connected by bus bars to form the energy storage device 100.

[0038] As shown in Fig. 4 , the third portion 33 of the side plate 3 is fixed to a screw hole 81 formed in the installation surface 8 on which the energy storage device 100 is to be installed. Specifically, a bolt 52 is inserted into a through hole (second side fixing portion) 331 of the third portion 33 and screwed into the screw hole 81 in the installation surface 8. The bolt 52 is an example of a fixing member. In this manner, the energy storage device 100 is fixed to the installation surface 8.

[0039] 7. Description of Effects The energy storage device 100 configured as described above has the following effects. (1) When the energy storage device 1 expands, the end plate 2 receives a force. If the end plate 2 and the installation surface 8 are fixed with bolts or the like, the force caused by the expansion of the energy storage device 1 acts directly on the bolt, which may damage the bolt. In contrast, according to this embodiment, the bolts 52 fasten the installation surface 8 to the third portion 33 formed on the side plate 3, rather than the end plate 2, and prevent the force caused by the expansion of the energy storage device 1 from acting directly on the third portion 33. Therefore, the bolts 52 fastening the third portion 33 to the installation surface 8 can be prevented from being damaged. In other words, it is possible to prevent the installation state of the energy storage device 100 from being impaired.

[0040] (2) The side plate 3 is formed from a single plate material, and the first portion 31, the second portion 32, and the third portion 33 are formed by bending the plate material. Because the side plate 3 can be formed by bending a single plate material, the side plate 3 can be easily manufactured.

[0041] (3) The thickness of the protruding portion 21 of the end plate 2 in the front-to-rear direction (first direction) is thicker than that of the end plate connection portion 23. This increases the thickness of the end plate 2 in the front-to-rear direction at the portion that receives the force caused by the expansion of the energy storage element, thereby suppressing deformation of the end plate 2. This makes the end plate 2 less susceptible to the effects of the expansion of the energy storage element 1. This reduces the effect of the force caused by the expansion of the energy storage element 1 on the bolts 81 that secure the energy storage device 100 to the installation surface 8. The second portion 32 of the side plate 3 is stacked on and fixed to the end plate 2, so the second portion 32 also contributes to suppressing deformation of the end plate 2.

[0042] (4) The energy storage element 1 expands in the front-to-rear direction. The second portion 32 of the side plate 3 is fixed to the end plate 2 in the front-to-rear direction. Because the second portion 32 is stacked and fixed to the end plate connection portion 23 of the end plate 2, it is less susceptible to the influence of the expansion of the energy storage element.

[0043] 8. Modifications Although one embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. The following modifications can be combined with the above embodiment, and modifications can also be combined with each other as appropriate.

[0044] (1) The side plate 3 is only required to have at least a first portion 31 extending in the front-rear direction, a second portion 32 fixed to the end plate 2, and a third portion 33 fixed to the installation surface 8, and the shapes of each portion are not particularly limited. Therefore, the fourth portion 34 and the fifth portion 35 are not necessarily required and may be provided as needed.

[0045] (2) In the above embodiment, the side plate 3 is formed by bending a single plate material, but it may also be formed by combining multiple members. In order to combine (connect) multiple plate materials, welding or caulking may be used in addition to screw fastening.

[0046] (3) The shape of the through hole 331 formed in the third portion 33 of the side plate 3 is not particularly limited, and may be an elongated hole extending in the front-rear direction (first direction) as shown in FIG. 3( b). This allows the position of the bolt 52 to be moved within the elongated hole 331 a. The energy storage device 100 is elongated in the front-rear direction because multiple energy storage elements 1 are arranged in the front-rear direction. This increases the dimensional tolerance of the fixing position of the energy storage device 100 to the installation surface. Therefore, if the through hole is an elongated hole, the tolerance can be absorbed and the bolt 52 can be fixed to the screw hole 81 in the installation surface 8 and the elongated hole 331 a.

[0047] (4) The method for fastening the third portion 33 to the installation surface 8 is not particularly limited, and various methods using a method other than the bolt 52 are possible. That is, it is sufficient that the third portion 33 and the installation surface 8 are fastened to each other. Examples of fastening methods other than the bolt include welding and crimping.

[0048] (5) In the above embodiment, the third portion 33 is provided at a position far from the first portion 31 in the left-right direction. (The third portion 33 is provided at a position closer to the center of the end plate 2 in the left-right direction and near the protrusion 21.) However, the position of the third portion 33 is not particularly limited. As shown in FIG. 5 , the third portion 33 can be provided in the second portion 32 near the first portion 31. This has the following advantages.

[0049] When the energy storage element 1 expands, there is a possibility that the vicinity of the center of the end plate 2 will be particularly deformed, but if the third portion 33 is provided in the vicinity of the first portion 31, that is, at a position separated in the left-right direction from the center of the end plate 2, it will be less affected by the deformation of the end plate 2. This reduces the effect that the deformation of the end plate 2 has on the strength of the fixation between the third portion 33 and the installation surface 8.

[0050] (6) The shape of the end plate 2 is not particularly limited as long as it can be disposed so as to be in direct or indirect contact with the energy storage devices 1 at both ends in the front-rear direction and can fix the second portions 32 of the side plates 3. In the above embodiment, the raised portion 21 is provided in the center of the end plate 2, but the shape of the front surface of the end plate 2 is not particularly limited as long as it can fix the second portions 32 of the side plates 3 as described above, and an embodiment without the raised portion 21 is also possible. The thickness of the end plate 2 is also not particularly limited, and it may be a plate-like shape like the side plates 3.

[0051] (7) The configuration of the energy storage element 1 is not particularly limited, and any known configuration of an energy storage element can be adopted. For example, the energy storage element 1 may have an elongated cylindrical shape instead of a rectangular parallelepiped shape. The energy storage element 1 may also have a pouch shape.

[0052] (8) In the above embodiment, the end plate 2 is a thick metal member with no hollow portions except for the through-holes, but this is not limited to this. The end plate may be entirely or partially lattice-shaped. The lattice creates space within the end plate, which allows the end plate to be lighter. In this case, the lattice shape provides rigidity to the end plate. The end plate 2 may also be a metal member with irregularities.

[0053] The present invention can be applied to an electricity storage device 100 including an electricity storage element such as a lithium ion secondary battery.

[0054] REFERENCE SIGNS LIST 1 Energy storage element 2 End plate 21 Protruding portion 23 End plate connecting portion 3 Side plate 31 First portion 32 Second portion 33 Third portion 8 Installation surface 100 Energy storage device

Claims

1. An energy storage device comprising: a plurality of energy storage elements arranged in a first direction; end plates arranged at ends of the plurality of energy storage elements in the first direction; and side plates arranged at ends of the plurality of energy storage elements in a second direction intersecting the first direction, wherein the end plates include end plate connection portions connected to the side plates, and the side plates comprise: a first portion extending in the first direction; a second portion extending from the first portion in the second direction and connected to the end plate connection portion; and a third portion extending from the second portion in the first direction along an installation surface of the energy storage device and fixed to the installation surface.

2. The energy storage device according to claim 1, wherein the side plate is formed from a single piece of plate material, and the first portion, the second portion, and the third portion are formed by bending the plate material.

3. The energy storage device according to claim 1, wherein the third portion has a long hole through which a fixing member for fixing the third portion to the installation surface is inserted.

4. The energy storage device according to claim 1, wherein the third portion is provided adjacent to the first portion in the second direction.

5. The power storage device according to claim 1, wherein the end plate includes a raised portion disposed adjacent to the end plate connection portion, and the thickness of the raised portion is greater than the thickness of the end plate connection portion in the first direction.