Power storage device

Abstract

This power storage device comprises a power storage element having a container, and a spacer arranged along the power storage element. The spacer is arranged in a first direction of the power storage element. The container is equipped with a joint. The spacer has a spacer body facing the power storage element in the first direction, and a first protrusion and a second protrusion protruding toward the power storage element. The second protrusion is formed of a plate-shaped portion curved toward the power storage element and is arranged at a position closer to the joint portion than the first protrusion. A first protruding length, which is a length by which the first protrusion protrudes beyond the spacer body, is shorter than a second protruding length, which is a length by which the second protrusion protrudes beyond the spacer body.

Description

Power storage device

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

[0002] Patent Document 1 discloses a battery pack consisting of multiple prismatic batteries. The multiple prismatic batteries are arranged with their long sides facing each other via a plate-shaped spacer made of resin. Multiple parallel ribs are formed on the surface of the spacer in a direction perpendicular to the arrangement of the prismatic batteries, and the multiple ribs abut against the long sides of the prismatic batteries. Multiple refrigerant passages, partitioned between adjacent ribs, are formed along the longitudinal direction of the ribs between adjacent prismatic batteries, and the cross-sectional area of ​​the multiple refrigerant passages gradually decreases from the center to the ends of the long sides of the prismatic batteries.

[0003] JP 2014-32932 A

[0004] In the spacers included in the conventional battery packs, although the thickness of the spacers between the ribs varies, each of the ribs has a similar structure, and the tip positions of the ribs in the thickness direction of the spacer are the same. Therefore, for example, a rib located close to the joint between the body and the cover plate of the battery case may press against the battery case, placing a relatively large load on the joint. This may cause problems such as deterioration of the joint.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide a power storage device with improved reliability.

[0006] An energy storage device according to one embodiment of the present invention comprises an energy storage element having a container, and a spacer arranged along the energy storage element, wherein the spacer is arranged in a first direction of the energy storage element, the container has a joint, the spacer has a spacer main body facing the energy storage element in the first direction, and a first convex portion and a second convex portion protruding toward the energy storage element, the second convex portion is formed of a plate-shaped portion curved toward the energy storage element and is arranged at a position closer to the joint than the first convex portion, and a first protruding length, which is the length by which the first convex portion protrudes beyond the spacer main body, is shorter than a second protruding length, which is the length by which the second convex portion protrudes beyond the spacer body.

[0007] According to the present invention, it is possible to provide a power storage device with improved reliability.

[0008] FIG. 1 is a perspective view showing the configuration of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view of an energy storage unit according to an embodiment. FIG. 3 is a perspective view showing the configuration of an energy storage element according to an embodiment. FIG. 4 is a perspective view showing the configuration of a spacer according to an embodiment. FIG. 5 is a cross-sectional view showing the positional relationship in the Z-axis direction between a spacer according to an embodiment and an energy storage element. FIG. 6 is a cross-sectional view showing a state in which a spacer according to an embodiment is arranged along an energy storage element. FIG. 7 is a cross-section of a spacer according to an embodiment, the cross-section including a vertically extending portion of a first convex portion.

[0009] (1) An energy storage device according to one embodiment of the present invention comprises an energy storage element having a container, and a spacer arranged along the energy storage element, the spacer being arranged in a first direction of the energy storage element, the container having a joint, the spacer having a spacer main body facing the energy storage element in the first direction, and a first convex portion and a second convex portion protruding toward the energy storage element, the second convex portion being formed of a plate-shaped portion curved toward the energy storage element and being arranged at a position closer to the joint than the first convex portion, and a first protruding length, which is the length by which the first convex portion protrudes beyond the spacer main body, being shorter than a second protruding length, which is the length by which the second convex portion protrudes beyond the spacer main body.

[0010] In an energy storage device according to one aspect of the present invention, the second convex portion is formed as a plate-shaped portion curved toward the energy storage element. Therefore, the spacer can press the joint or a position close to the joint with a relatively weak force by the second convex portion, and further, the first convex portion located away from the joint can compress the container. Therefore, the positional stability of the energy storage element in the energy storage device is improved, while deterioration or damage to the joint of the energy storage element is suppressed. Thus, the energy storage device according to this aspect is an energy storage device with improved reliability.

[0011] (2) In the energy storage device described in (1) above, the spacer may further include a third convex portion protruding toward the energy storage element, and in a second direction perpendicular to the first direction, at least a portion of the first convex portion may be arranged between the second convex portion and the third convex portion, and a third protruding length, which is the length by which the third convex portion protrudes beyond the spacer body, may be longer than the first protruding length.

[0012] According to the energy storage device described above in (2), the third convex portion has a longer protrusion length than the first convex portion and is located farther from the joint than the first convex portion, so that the spacer can more reliably compress the energy storage element while preventing deterioration or damage to the joint.

[0013] (3) In the energy storage device described in (2) above, the first convex portion may include a horizontally extending portion extending in a third direction perpendicular to the first direction and the second direction and arranged between the second convex portion and the third convex portion, and a vertically extending portion extending in the second direction and aligned with the third convex portion in the third direction, and the first protruding length may be the length by which the horizontally extending portion protrudes beyond the spacer body, and the length by which the vertically extending portion protrudes beyond the spacer body may be longer than the first protruding length.

[0014] According to the energy storage device described in (3) above, the longitudinally extending portion that is a part of the first convex portion functions as a portion that compresses the energy storage element at a position relatively far from the joint, similar to the third convex portion, thereby further improving the positional stability of the energy storage element in the energy storage device.

[0015] (4) In the energy storage device described in (2) or (3) above, a plurality of the third protrusions may be arranged on the spacer body in the second direction.

[0016] According to the electricity storage device described in (4) above, the third protrusions form a plurality of gas flow paths aligned in the second direction, thereby efficiently dissipating heat from the electricity storage elements.

[0017] (5) In the energy storage device according to any one of (1) to (4) above, the first convex portion may be formed by a thick portion of the spacer body.

[0018] According to the energy storage device described above in (5), the first convex portion has a relatively short protruding length and a relatively high rigidity, and therefore can more reliably support the container of the energy storage element at a position relatively far from the joint portion of the container while reducing the load on the joint portion.

[0019] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including modifications thereof). The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the X-axis direction is defined as the direction in which a pair of terminals of an energy storage element are aligned, or the direction in which a pair of short side surfaces of a container for the energy storage element face each other. The Y-axis direction is defined as the direction in which a pair of long side surfaces of a container for the energy storage element face each other, the thickness direction (flattening direction) of the container for the energy storage element, or the direction in which multiple energy storage elements of the energy storage unit are aligned. The Z-axis direction is defined as the direction in which the terminals of the energy storage element protrude, the direction in which the container body and the cover plate of the energy storage element are aligned, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the usage mode, the Z-axis direction may not be the up-down direction; however, for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0021] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. When referring to one side and the other side of the X-axis direction, it refers to one and the other of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the directions or attitudes are not strictly those of the two directions. For example, when two directions are parallel, it does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, that is, there is a difference of, for example, about a few percent.

[0022] In the following description, unless otherwise specified, ordinal numbers such as "first" and "second" do not refer to the number or order of the elements (components, parts, events, etc.) to which the ordinal numbers are attached, but are used for the purpose of avoiding confusion among multiple elements and distinguishing each of the multiple elements from the other elements. In the following description, when the term "insulation" is used, it means "electrical insulation." An insulating material has a volume resistivity of 1×10 ６ Ωm or more, more preferably 1×10 ７ Ωm or more, more preferably 1×10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0023] (Embodiment) [1. General Description of Energy Storage Device 1] Fig. 1 is a perspective view showing the configuration of an energy storage device 1 according to an embodiment. Fig. 1 shows a state in which an energy storage unit 10 is removed from a case main body 610. Fig. 2 is an exploded perspective view of the energy storage unit 10 according to an embodiment. Fig. 2 shows three energy storage elements 100 and four spacers 200, which are arranged continuously in the Y-axis direction, out of the multiple energy storage elements 100 and multiple spacers 200 included in the energy storage unit 10. The Y-axis direction is an example of a first direction. Fig. 3 is a perspective view showing the configuration of the energy storage element 100 according to an embodiment.

[0024] The power storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source. The power storage device 1 is, for example, a battery module (battery assembly) used for power storage or power supply purposes. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, automatic guided vehicle (AGV), or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0025] 1 , the energy storage device 1 includes an energy storage unit 10 and a case 600 that houses the energy storage unit 10. In addition to the above components, the energy storage device 1 may also include a bus bar unit including a plurality of bus bars connected to the plurality of energy storage elements 100, and electrical devices such as a circuit board and a relay that monitor or control the charge state, discharge state, etc. of the energy storage unit 10.

[0026] In this embodiment, the energy storage unit 10 is a battery module having one or more energy storage elements 100. Specifically, the energy storage unit 10 includes a plurality of energy storage elements 100 (34 in this embodiment), a spacer 200 disposed between two adjacent energy storage elements 100 in the Y-axis direction, and spacers 250 disposed outside each of the energy storage elements 100 at both ends in the Y-axis direction.

[0027] The energy storage unit 10 has a generally rectangular parallelepiped shape that is long in the Y-axis direction, with a plurality of energy storage elements 100, a plurality of spacers 200, and a pair of spacers 250 arranged in the Y-axis direction. Conductive members such as bus bars (not shown) are connected to the terminals 140 of the plurality of energy storage elements 100 included in the energy storage unit 10. The rectangular parallelepiped here refers to a hexahedron with all faces formed into rectangles or squares.

[0028] In this embodiment, the energy storage unit 10 is a non-constraint type module that does not include restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 100 in the Y-axis direction. However, the energy storage unit 10 may include restraining members that restrain the plurality of energy storage elements 100 and the plurality of spacers 200 and 250 in the Y-axis direction.

[0029] The energy storage element 100 is a secondary battery (single cell), more specifically, a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. As shown in FIGS. 2 and 3 , the energy storage element 100 includes a flat rectangular (square) container 101. The container 101 contains an electrode assembly, a current collector, an electrolyte, and other components (not shown). The electrode assembly may be, for example, a wound electrode assembly formed by winding an electrode plate and a separator. The electrode plate includes a current collector foil, which is a long strip of metal foil, and an active material layer formed on the surface of the current collector foil. The electrode assembly may be a stacked electrode assembly formed by stacking multiple flat electrode plates, or an electrode assembly having a structure in which long strip electrode plates are stacked in an accordion-like manner by repeatedly folding in a mountain and a valley. The electrolyte contained in the container 101 may be of any type, and various types may be selected as long as it does not impair the performance of the energy storage element 100. The energy storage element 100 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 100 may be a primary battery. The energy storage element 100 may be a battery using a solid electrolyte. The shape of the energy storage element 100 is not limited to the above-mentioned rectangular shape, and may be other shapes such as a polygonal column, a cylindrical column, an elliptical column, or an oblong column.

[0030] As shown in FIG. 3 , the container 101 is a rectangular parallelepiped case including a pair of long sides 111, a pair of short sides 112, and a bottom surface 113 formed by the container body 102, and a terminal placement surface 115 formed by the cover plate 103. After an electrode assembly and the like are housed inside the container body 102, the container body 102 and the cover plate 103 are welded together, thereby sealing the interior of the container 101. That is, the energy storage device 100 according to this embodiment includes a joint 130, which is a joint between the container body 102 and the cover plate 103. The joint 130 is formed to extend in the X-axis direction and the Y-axis direction, which intersect with the Z-axis direction, which is the alignment direction of the container body 102 and the cover plate 103. In this embodiment, the portion where the container body 102 and the cover plate 103 are fused together by welding, is treated as the joint 130. The material of the container 101 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, an aluminum alloy, iron, or plated steel sheet. The joining method used to form the joint 130 is not limited to welding, and the joint 130 may be formed by crimping, fitting, adhesive, etc. However, from the viewpoint of high sealing performance and high durability, it is preferable that the joint 130 be formed by welding.

[0031] The energy storage element 100 includes terminals 140 arranged in the Z-axis direction. The Z-axis direction is an example of a second direction. The terminals 140 are electrically connected to an electrode assembly housed in the container 101. More specifically, a pair of terminals 140 are arranged to protrude in the positive direction of the Z-axis from a terminal arrangement surface 115 of the container 101. A gas exhaust valve 131 is further provided on the terminal arrangement surface 115. One of the pair of terminals 140 is electrically connected to the positive electrode of the electrode assembly, and the other is electrically connected to the negative electrode of the electrode assembly. The terminals 140 are formed of a metal such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0032] The spacers 200 and 250 are insulating or heat insulating plates that are arranged in the positive or negative Y-axis direction of the energy storage elements 100 and that insulate and / or heat the energy storage elements 100 from each other or from the energy storage elements 100 to other components. In this embodiment, the spacers 200 and 250 are formed of an insulating material such as resin. The spacer 200 is also called, for example, an "inter-cell spacer." The spacer 250 is also called, for example, an "end spacer." In this embodiment, the spacers 200 and 250 also function as cell holders that hold one or more energy storage elements 100 arranged along the spacer 200 or 250.

[0033] The spacer 200 includes a spacer main body 201 facing the energy storage elements 100 in the Y-axis direction, and a side wall portion 202 facing the energy storage elements 100 in the X-axis direction. In this embodiment, the side wall portion 202 is arranged to extend from the end of the spacer main body 201 in the X-axis direction in both the positive and negative Y-axis directions, thereby facing the two energy storage elements 100 held by the spacer 200 in the X-axis direction. The spacer 200 further includes a bottom wall portion 203 facing the bottom surface 113 of the energy storage elements 100. The bottom wall portion 203 is arranged to extend from the end of the spacer main body 201 in the negative Z-axis direction in both the positive and negative Y-axis directions, thereby facing the two energy storage elements 100 held by the spacer 200 in the Z-axis direction.

[0034] In this embodiment, the side wall portion 202 is composed of multiple portions separated in the Z-axis direction, but the side wall portion 202 may also be composed of a single wall portion that is continuous in the Z-axis direction. The side wall portion 202 may have any size and shape that does not interfere with the side wall portion 202 of the spacer 200 that has the side wall portion 202 and the side wall portion 202 of another spacer 200 that is adjacent to the spacer 200. Specifically, when two spacers 200 lined up in the Y-axis direction are combined, the side wall portions 202 of the two spacers 200 may have any size and shape that does not interfere with the combination of the two spacers 200.

[0035] The spacer 200 according to this embodiment has a plurality of protrusions that come into contact with the energy storage elements 100 arranged in the positive direction of the Y axis. These plurality of protrusions are provided on the spacer 200 so as to apply a balanced pressure to the energy storage elements 100. Details of the plurality of protrusions provided on the spacer 200 will be described later with reference to FIGS. 4 to 7.

[0036] The spacer 250 is arranged along the energy storage elements 100 at the ends in the Y-axis direction of the energy storage unit 10. The spacer 250 is almost the same as the spacer 200 except that the number of energy storage elements 100 facing the spacer 250 in the Y-axis direction is one, and therefore a description of the configuration of the spacer 250 will be omitted.

[0037] The case 600 is a container having a substantially rectangular parallelepiped (box-like) shape that houses the energy storage unit 10. The case 600 is disposed outside the energy storage unit 10 and protects the energy storage unit 10 from impacts and the like. The case 600 is formed from a metal member such as aluminum, an aluminum alloy, stainless steel, iron, or a plated steel plate. In this embodiment, the case 600 is formed by die-casting aluminum (aluminum die-casting). Instead of the case 600, a case formed from an insulating member such as a resin material may be used as the case that houses the energy storage unit 10.

[0038] As shown in FIG. 1 , the case 600 has a case main body 610. The case main body 610 is a housing (enclosure) having an opening 610a formed in the positive direction of the Z axis and sized to allow insertion of the power storage unit 10. The case main body 610 includes a case side wall 611 facing the power storage unit 10 in the X axis direction, a case side wall 612 facing the power storage unit 10 in the Y axis direction, and a case bottom wall 615 supporting the power storage unit 10 from the negative direction of the Z axis. The X axis direction is an example of a third direction. The case 600 may further include a lid (not shown) that closes the opening 610a of the case main body 610.

[0039] [2. Regarding the Spacer 200 and Its Surrounding Structure] Next, the spacer 200 and its surrounding structure will be described using FIGS. 4 to 7 in addition to the above-described FIGS. 1 to 3 . FIG. 4 is a perspective view showing the structure of the spacer 200 according to an embodiment. FIG. 5 is a cross-sectional view showing the positional relationship between the spacer 200 according to an embodiment and the energy storage element 100 in the Z-axis direction. FIG. 5 schematically shows partial cross sections of the spacer 200 and the energy storage element 100 in the YZ plane passing through the V-V line shown in FIG. 4 . FIG. 5 omits illustration of sidewall portions 202 and the like located in the negative X-axis direction of the cross section of the spacer 200. FIG. 5 omits illustration of elements (such as electrodes) inside the container 101 of the energy storage element 100 and insulating members insulating the terminals 140 from the container 101. These supplementary notes regarding FIG. 5 also apply, as appropriate, to FIGS. 6 and 7 below.

[0040] Fig. 6 is a cross-sectional view showing a state in which the spacer 200 according to the embodiment is arranged along the energy storage device 100. Fig. 7 is a cross-sectional view of the spacer 200 according to the embodiment, which is a view showing a cross-section including the longitudinally extending portion 215 of the first convex portion 210. Fig. 7 schematically shows a cross-section of a portion of the spacer 200 in the YZ plane passing through the line VII-VII shown in Fig. 4.

[0041] 4 to 6, the spacer 200 according to this embodiment has a plurality of protrusions that protrude toward the energy storage device 100. The plurality of protrusions include a first protrusion 210, a second protrusion 220, and a third protrusion 230. The first protrusion 210, the second protrusion 220, and the third protrusion 230 function as portions that press against the long side surface 111 of the energy storage device 100, as shown in FIG.

[0042] More specifically, when the energy storage unit 10 including the plurality of spacers 200 and the plurality of energy storage elements 100 is housed in the case body 610 (see FIG. 1 ), the energy storage unit 10 is housed in the case body 610 while being compressed in the Y-axis direction. The energy storage unit 10 housed in the case body 610 is restrained in the Y-axis direction by a pair of case side wall portions 612 that face each other in the Y-axis direction. As a result, the first convex portion 210, the second convex portion 220, and the third convex portion 230 of the spacer 200 are in a state of compressing the long side surface 111 of the energy storage elements 100, as shown in FIG. 6 . The restraint of the energy storage unit 10 in the Y-axis direction does not need to be performed by the case body 610, and the energy storage device 1 may include a restraining member that restrains the energy storage unit 10 in the Y-axis direction, as described above.

[0043] In this embodiment, the first convex portion 210, the second convex portion 220, and the third convex portion 230 each have a different contact position with the energy storage element 100 in the Z-axis direction, and the first convex portion 210 and the second convex portion 220 have different protruding lengths. Furthermore, the first convex portion 210 and the third convex portion 230 also have different protruding lengths.

[0044] 5 and 6 , in the spacer 200, the second convex portion 220, the first convex portion 210, and the third convex portion 230 are arranged side by side in the Z-axis direction in order of proximity to a position P in the Z-axis direction of the joint 130 provided on the container 101 of the energy storage element 100. In this embodiment, the position of the lower end of the joint 130 (the end in the negative Z-axis direction) is defined as the position P of the joint 130.

[0045] In this way, the second convex portion 220 is disposed in a position close to the position P of the joint 130 in the Z-axis direction. In other words, the second convex portion 220 is located in a position that is likely to mechanically affect the joint 130 when the container 101 of the energy storage element 100 is compressed. The second convex portion 220 disposed in this position is configured to prevent the force pressing the container 101 in the positive direction of the Y-axis from becoming excessive. The first convex portion 210, which is disposed in a position farther from the joint 130 than the second convex portion 220 in the Z-axis direction, is configured to compress the container 101 with a greater force than the second convex portion 220. Furthermore, the third convex portion 230, which is disposed in a position farther from the joint 130 than the first convex portion 210 in the Z-axis direction, is configured to efficiently suppress expansion of the container 101 of the energy storage element 100. More specifically, the configuration of the energy storage device 1 according to this embodiment is described, for example, as follows.

[0046] The energy storage device 1 according to this embodiment includes an energy storage element 100 having a container 101, and a spacer 200 arranged along the energy storage element 100. The spacer 200 is arranged in the Y-axis direction of the energy storage element 100. The container 101 includes a joint 130. The spacer 200 includes a spacer main body 201 facing the energy storage element 100 in the Y-axis direction, and a first convex portion 210 and a second convex portion 220 that protrude toward the energy storage element 100. The second convex portion 220 is formed of a plate-like portion that curves toward the energy storage element 100, and is arranged at a position closer to the joint 130 than the first convex portion 210. A first protrusion length L1, which is the length by which the first convex portion 210 protrudes beyond the spacer main body 201, is shorter than a second protrusion length L2, which is the length by which the second convex portion 220 protrudes beyond the spacer main body 201.

[0047] Thus, in this embodiment, second convex portion 220 is formed of a plate-like portion curved toward energy storage element 100. Therefore, spacer 200 can press joint 130 or a position close to joint 130 with a relatively weak force by second convex portion 220, and further can compress container 101 by first convex portion 210 located away from joint 130.

[0048] More specifically, when the second convex portion 220, which is formed by a plate-shaped portion curved toward the energy storage device 100, receives a reaction force in the negative Y-axis direction from the energy storage device 100, it is easily deformed by the reaction force. Furthermore, because the second protrusion length L2 is longer than the first protrusion length L1, the first protrusion 210 is unlikely to interfere with contact between the second convex portion 220 and the container 101. In other words, as shown in FIG. 6 , when the spacer 200 is placed at a position where the first protrusion 210 and the container 101 contact each other in the Y-axis direction, the second convex portion 220 always comes into contact. Furthermore, due to the high deformability (low rigidity) of the second convex portion 220, the force with which the second convex portion 220 presses the container 101 is unlikely to be excessive. Here, when the same force is applied, a member that deforms a lot is considered to have "low rigidity," and a member that deforms a little is considered to have "high rigidity." That is, the spacer 200 according to this embodiment can hold at least two locations in a balanced manner: a location close to the joint 130 of the container 101 of the energy storage element 100, and a location farther from the joint 130 than the location mentioned above. This improves the positional stability of the energy storage element 100, while suppressing deterioration or damage to the joint 130 of the energy storage element 100. Therefore, the energy storage device 1 according to this embodiment is an energy storage device with improved reliability.

[0049] In particular, when no convex portions other than the first convex portion 210 and the second convex portion 220 are arranged between the first convex portion 210 and the second convex portion 220, the distance between the first convex portion 210 and the second convex portion 220 can be reduced. That is, the degree of freedom in the position at which the first convex portion 210 is arranged relative to the second convex portion 220 on the long side surface 111 of the energy storage element 100 is increased. Furthermore, when the first convex portion 210 protrudes from the spacer main body 201 toward the energy storage element 100 and is formed integrally with the spacer main body 201, the rigidity of the first convex portion 210 becomes relatively high. That is, the first convex portion 210 located away from the joint 130 can press the container 101 more firmly.

[0050] In this embodiment, the spacer body 201 is a plate-like portion having a substantially uniform thickness (width in the Y-axis direction) T and arranged in an orientation perpendicular to the Y-axis direction, which is the arrangement direction of the energy storage devices 100. The protruding lengths (L1, L2) of the first convex portion 210 and the second convex portion 220 from the spacer body 201 are the protruding lengths from the surface of the spacer body 201 in the protruding direction of these convex portions when the spacer 200 is not arranged along the energy storage devices 100, as shown in FIG.

[0051] That is, the reference for the protrusion lengths (L1, L2) in this embodiment is the surface of the spacer body 201 in the positive Y-axis direction. Therefore, the fact that the second protrusion length L2 is longer than the first protrusion length L1 can also be rephrased as the tip position of the second convex portion 220 being located in the positive Y-axis direction relative to the tip position of the first convex portion 210. The same applies to the protrusion length L3 of the third convex portion 230 from the spacer body 201, which will be described later.

[0052] In this embodiment, the first convex portion 210 also functions as a portion that forms a flow path for a gas (e.g., air; the same applies below) that cools the energy storage element 100. Specifically, as shown in FIG. 4 , the first convex portion 210 is provided extending along the spacer main body 201, and the gas can exchange heat with the energy storage element 100 while flowing along the spacer main body 201 and the first convex portion 210. For example, the first convex portion 210 and the second convex portion 220 both have portions that extend in the X-axis direction. This forms a gas flow path between the first convex portion 210 and the second convex portion 220. The second convex portion 220 is located above the gas flow path (in the positive Z-axis direction), and therefore also functions as a seal portion that prevents the gas from leaking upward (in the positive Z-axis direction).

[0053] In this embodiment, the first convex portion 210 is provided at a position opposite to the main body portion of the electrode body (not shown) included in the energy storage element 100 in the Y-axis direction. The main body portion of the electrode body is a portion where an active material layer forming portion, which is a portion where the active material layer of the electrode plate is formed, is stacked. In other words, the first convex portion 210 is provided at a position opposite to the active material layer forming portion of the electrode body in the Y-axis direction. This allows the first convex portion 210 to efficiently suppress bulging of the energy storage element 100 in the Y-axis direction, i.e., bulging of the electrode body in the Y-axis direction.

[0054] In this embodiment, the second convex portion 220 is formed further outward in the X-axis direction than the active material layer forming portion of the electrode body (not shown) of the energy storage element 100, and is longer in the X-axis direction than the first convex portion 210. Specifically, as shown in FIG. 4 , for example, the second convex portion 220 is formed from the spacer body 201 to the side wall portion 202 of the spacer 200. This shape allows the second convex portion 220 to be in close contact with the long side surface 111 and the short side surface 112 of the energy storage element 100. As a result, the second convex portion 220 can more reliably perform the function of the sealing portion described above, i.e., the function of suppressing leakage of gas for cooling the energy storage element 100.

[0055] More specifically, the first convex portion 210 according to this embodiment is formed by a thick portion of the spacer body 201. That is, in this embodiment, it can also be explained that the second convex portion 220 is a hollow portion, whereas the first convex portion 210 is a solid portion.

[0056] That is, the first protrusion length L1 of the first convex portion 210 according to the present embodiment is relatively short and has relatively high rigidity, so that the first convex portion 210 can more reliably support the container 101 while suppressing the load on the joint portion 130 at a position on the container 101 of the energy storage element 100 that is relatively far from the joint portion 130.

[0057] The spacer 200 according to this embodiment further includes a third convex portion 230 that protrudes toward the energy storage device 100. In the Z-axis direction, at least a portion of the first convex portion 210 is disposed between the second convex portion 220 and the third convex portion 230 (see FIGS. 4 to 6 ). In the spacer 200 configured in this manner, as shown in FIG. 5 , a third protruding length L3, which is the length by which the third convex portion 230 protrudes beyond the spacer body 201, is longer than the first protruding length L1.

[0058] As described above, in the present embodiment, the third convex portion 230 has a longer protrusion length than the first convex portion 210, and is positioned farther from the joint 130 than the first convex portion 210, so that the energy storage element 100 can be compressed by the third convex portion 230. Therefore, the spacer 200 can more reliably compress the energy storage element 100 in a manner that is less likely to cause deterioration or damage to the joint 130. Furthermore, because the third protrusion length L3 is longer than the first protrusion length L1, the third convex portion 230 can more reliably press the central portion in the Z-axis direction of the long side surface 111, which is a portion of the container 101 of the energy storage element 100 that is prone to expansion. In other words, the spacer 200 according to the present embodiment can efficiently suppress the expansion of the energy storage element 100 by the third convex portion 230.

[0059] More specifically, when the spacer 200 is not disposed along the energy storage device 100 (see FIG. 5 ), the third protrusion length L3 is preferably longer than the first protrusion length L1 and shorter than the second protrusion length L2. This allows the second protrusion 220, which has low rigidity, to be more reliably brought into contact with the joint 130 of the container 101 or a position close to the joint 130, when the spacer 200 is disposed along the energy storage device 100 (see FIG. 6 ), and allows the third protrusion 230 to compress a position of the container 101 far from the joint 130. In this embodiment, the third protrusion 230 is formed by a thick portion of the spacer body 201, similar to the first protrusion 210. In other words, the third protrusion 230 is a solid portion.

[0060] In particular, when no convex portions other than the first convex portion 210 and the third convex portion 230 are arranged between the first convex portion 210 and the third convex portion 230, the distance between the first convex portion 210 and the third convex portion 230 can be reduced. In other words, the degree of freedom in the position at which the third convex portion 230 is arranged relative to the first convex portion 210 on the long side surface 111 of the energy storage element 100 is increased.

[0061] In this embodiment, as shown in FIG. 4 , the first convex portion 210 has a portion extending in the X-axis direction and a portion extending in the Y-axis direction. Specifically, the first convex portion 210 includes a horizontally extending portion 211 that extends in the X-axis direction and is disposed between the second convex portion 220 and the third convex portion 230, and a vertically extending portion 215 that extends in the Z-axis direction and is aligned with the third convex portion 230 in the X-axis direction. The first protrusion length L1 is the length by which the horizontally extending portion 211 protrudes beyond the spacer main body 201 in the Y-axis direction. The length by which the vertically extending portion 215 protrudes beyond the spacer main body 201 in the Y-axis direction is longer than the first protrusion length L1. More specifically, as shown in FIGS. 4 and 7 , the first convex portion 210 includes the horizontally extending portion 211 that extends in the X-axis direction, the vertically extending portion 215 that extends in the Z-axis direction, and a connecting portion 213 that connects the horizontally extending portion 211 and the vertically extending portion 215. When the length of the vertical extension portion 215 that protrudes beyond the spacer body 201 is defined as a fourth protrusion length L4, L1<L4. As shown in FIG. 7 , the connecting portion 213 has an inclined surface that connects the horizontal extension portion 211 and the vertical extension portion 215 that have different protrusion lengths beyond the spacer body 201.

[0062] According to this configuration, the vertical extension portion 215, which is a part of the first convex portion 210, functions as a portion that compresses the energy storage element 100 at a position relatively far from the joint portion 130, similar to the third convex portion 230. This further improves the positional stability of the energy storage element 100 in the energy storage device 1. More specifically, the fourth protrusion length L4 of the vertical extension portion 215 is substantially the same as the third protrusion length L3 of the third convex portion 230. Therefore, contact of the vertical extension portion 215 and the third convex portion 230 with one of the containers 101 is unlikely to interfere with contact of the vertical extension portion 215 and the third convex portion 230 with the other container 101. In other words, each of the vertical extension portion 215 and the third convex portion 230 can appropriately contact the container 101. The vertical extension portion 215 may also function as a portion that efficiently suppresses expansion of the energy storage element 100, similar to the third convex portion 230.

[0063] In this embodiment, as shown in FIGS. 4 to 6, the spacer body 201 has a plurality of third convex portions 230 arranged side by side in the Z-axis direction.

[0064] In this way, by arranging multiple third convex portions 230 including portions extending in the X-axis direction in the Z-axis direction, multiple gas flow paths aligned in the Z-axis direction are formed. This allows efficient release of heat from the energy storage element 100. In other words, the multiple third convex portions 230 function as portions that improve the positional stability of the energy storage element 100, and also function as portions for efficiently releasing heat from the energy storage element 100, in other words, portions for efficiently cooling the energy storage element 100.

[0065] 4 to 6, in this embodiment, a gas flow path is also formed between the first convex portion 210 and the third convex portion 230. This allows heat exchange with the gas to occur over a relatively wide area of ​​the long side surface 111 of the energy storage element 100.

[0066] In this embodiment, two of the multiple third convex portions 230 have a third horizontal extending portion 231 and a third vertical extending portion 235 extending in the X-axis direction, similar to the first convex portion 210 (see FIG. 4 ). This allows the multiple third convex portions 230, together with the first convex portion 210, to form multiple gas flow paths extending in the Z-axis direction. This is advantageous from the viewpoint of efficiently releasing heat from the energy storage element 100.

[0067] In this embodiment, the first convex portion 210 and the multiple third convex portions 230 are solid portions as described above, and form so-called comb-tooth-shaped portions in the spacer 200, as shown in, for example, FIGS. 4 to 6 . However, this is not required. The first convex portion 210 and the third convex portion 230 may each be formed as a plate-shaped portion curved toward the energy storage element 100, similar to the second convex portion 220, as long as the required mechanical strength can be ensured. In other words, the first convex portion 210 and the multiple third convex portions 230 may each be hollow portions. That is, the first convex portion 210 and the multiple third convex portions 230 may form so-called bellows-shaped portions in the spacer 200. In this case, the first convex portion 210 and the multiple third convex portions 230 may be located on both sides of the spacer 200 in the Y-axis direction. This allows the spacer 200 to appropriately compress the two energy storage elements 100 arranged on both sides of the spacer 200 in the Y-axis direction. The two energy storage elements 100 can be efficiently cooled by gas flowing through the multiple flow paths formed by the first convex portion 210 and the multiple third convex portions 230 of the spacer 200.

[0068] [3. Description of Modifications] While the energy storage device 1 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0069] In the above embodiment, only one of the two surfaces of the spacer 200 in the Y-axis direction is provided with a plurality of convex portions, such as the first convex portions 210, that come into contact with the energy storage elements 100 (see FIGS. 4 to 7 ). However, a plurality of convex portions, such as the first convex portions 210, may be provided on both surfaces of the spacer 200 in the Y-axis direction. However, from the viewpoint of, for example, suppressing an increase in the length of the energy storage unit 10 including a plurality of spacers 200 in the Y-axis direction, it is preferable that only one of the two surfaces of the spacer 200 in the Y-axis direction is provided with a plurality of convex portions, such as the first convex portions 210, that come into contact with the energy storage elements 100.

[0070] The spacer 200 does not necessarily have to hold two energy storage elements 100. The spacer 200 may hold only one energy storage element 100. In other words, the side wall portion 202 of the spacer 200 may be arranged to extend from the end of the spacer main body 201 in the X-axis direction to only one side in the Y-axis direction. In this case, the bottom wall portion 203 of the spacer 200 may be arranged to extend from the end of the spacer main body 201 in the negative Z-axis direction to only that one side in the Y-axis direction. Even in this case, the spacer 200 can be provided with multiple convex portions, such as the first convex portion 210, that come into contact with the energy storage elements 100.

[0071] The spacer 200 does not need to have a function of holding the energy storage elements 100. For example, only the spacer body 201 having a plurality of convex portions such as the first convex portion 210 may be treated as the spacer 200. In this case, the spacer 200 and the energy storage elements 100 adjacent to the spacer 200 may be connected by, for example, double-sided adhesive tape or adhesive.

[0072] The spacer 200 does not necessarily have to include the third convex portion 230. The spacer 200 is required to include at least the first convex portion 210 and the second convex portion 220. This allows the second convex portion 220 to press the joint 130 or a position close to the joint 130 with a relatively weak force, and allows the first convex portion 210 located away from the joint 130 to compress the container 101. When the spacer 200 does not include the third convex portion 230, for example, a plate-like member for compressing the central portion may be disposed between the spacer main body 201 and the central portion in the Z-axis direction and the X-axis direction of the long side surface 111 (see FIG. 3 ) of the container 101.

[0073] The joint 130 of the container 101 does not have to be the portion where the container body 102 and the cover plate 103 are joined. For example, if there is a portion where a liquid filling tap that closes the liquid filling port and the container body 102 are joined at the end of the long side surface 111 in the positive direction of the Z axis, this joined portion may be treated as the joint 130 of the container 101. Even in this case, the second convex portion 220 presses the joint 130 or a position close to the joint 130 with a relatively weak force. This prevents deterioration or damage to the joint 130 while improving the positional stability of the energy storage element 100. The position of the joint 130 is also not particularly limited, as long as it is located at any position on the long side surface 111 that faces the spacer 200. In other words, the joint 130 of the container 101 may be the portion where two members or parts of the container 101 are joined.

[0074] In the above embodiment, the Z-axis direction is an example of the second direction, and the X-axis direction is an example of the third direction. However, the X-axis direction may be an example of the second direction, and the Z-axis direction may be an example of the third direction. That is, in the X-axis direction, at least a portion of the first convex portion 210 may be disposed between the second convex portion 220 and the third convex portion 230. In this case, the first convex portion 210 may include a horizontally extending portion 211 extending in the Z-axis direction and disposed between the second convex portion 220 and the third convex portion 230, and a vertically extending portion 215 extending in the X-axis direction and aligned with the third convex portion 230 in the Z-axis direction. That is, for example, the joint portion 130 may be disposed at an end of the long side surface 111 of the container 101 in the X-axis direction, and the second convex portion 220, the first convex portion 210, and the third convex portion 230 may be disposed on the spacer 200 aligned in the X-axis direction in order of proximity to the joint portion 130 in the X-axis direction.

[0075] In the above embodiment, the position at which the second convex portion 220 contacts the container 101 is below the position P of the bonding portion 130 (in the negative Z-axis direction), but the second convex portion 220 may also contact the bonding portion 130. Even in this case, the second convex portion 220 is formed of a plate-shaped portion that curves toward the energy storage element 100, and is therefore likely to deform due to the reaction force received from the bonding portion 130. This prevents deterioration or damage to the bonding portion 130 caused by the second convex portion 220 pressing against the bonding portion 130.

[0076] It is not essential that the first convex portion 210 has both the horizontally extending portion 211 and the vertically extending portion 215. The first convex portion 210 needs to have at least the horizontally extending portion 211. In other words, it is sufficient that the first convex portion 210 has a first protruding length L1 that is shorter than the second protruding length L2 and can contact the container 101 of the energy storage element 100 at a position farther from the joint portion 130 in the Z-axis direction than the second convex portion 220.

[0077] The length in the X-axis direction of the first convex portion 210 and the second convex portion 220 does not need to be a length that contacts almost the entire area of ​​the long side surface 111 of the container 101 in the X-axis direction. The length in the X-axis direction of the first convex portion 210 and the second convex portion 220 may be, for example, a length that contacts only a predetermined range including the center of the long side surface 111 in the X-axis direction. The predetermined range may be approximately 1 / 3 of the length of the long side surface 111 in the X-axis direction. However, from the viewpoint of more reliably improving the positional stability of the energy storage element 100, the predetermined range is preferably longer than 1 / 3 of the length of the long side surface 111 in the X-axis direction, and more preferably longer than 1 / 2 of that length. More preferably, the predetermined range is the same as the length of the long side surface 111 in the X-axis direction.

[0078] The energy storage device 1 does not need to include the case 600. For example, the energy storage unit 10 including the plurality of energy storage elements 100 and the plurality of spacers 200 may be housed as the energy storage device 1 in some kind of device, a rack, or the like.

[0079] Any combination of the components of the above-described embodiment and its modifications is also included within the scope of the present invention.

[0080] The present invention can be applied to an electricity storage device or the like that includes an electricity storage element such as a lithium ion secondary battery.

[0081] REFERENCE SIGNS LIST 1 Energy storage device 100 Energy storage element 101 Container 102 Container body 103 Cover plate 130 Joint portion 200, 250 Spacer 201 Spacer body 210 First convex portion 211 Laterally extending portion 213 Connection portion 215 Vertically extending portion 220 Second convex portion 230 Third convex portion 231 Third horizontally extending portion 235 Third vertically extending portion 600 Case 610 Case body L1 First protruding length L2 Second protruding length L3 Third protruding length L4 Fourth protruding length

Claims

1. An energy storage device comprising: an energy storage element having a container; and a spacer arranged along the energy storage element, wherein the spacer is arranged in a first direction of the energy storage element; the container has a joint; the spacer has a spacer body facing the energy storage element in the first direction, and a first convex portion and a second convex portion protruding toward the energy storage element, wherein the second convex portion is formed of a plate-like portion curved toward the energy storage element and is arranged at a position closer to the joint than the first convex portion, and a first protruding length, which is the length by which the first convex portion protrudes beyond the spacer body, is shorter than a second protruding length, which is the length by which the second convex portion protrudes beyond the spacer body.

2. The energy storage device according to claim 1, wherein the spacer further comprises a third convex portion that protrudes toward the energy storage element, and in a second direction perpendicular to the first direction, at least a portion of the first convex portion is disposed between the second convex portion and the third convex portion, and a third protruding length, which is the length by which the third convex portion protrudes beyond the spacer body, is longer than the first protruding length.

3. The energy storage device according to claim 2, wherein the first convex portion includes: a horizontally extending portion that extends in a third direction perpendicular to the first direction and the second direction and is disposed between the second convex portion and the third convex portion; and a vertically extending portion that extends in the second direction and is aligned with the third convex portion in the third direction; the first protruding length is a length by which the horizontally extending portion protrudes beyond the spacer body; and the length by which the vertically extending portion protrudes beyond the spacer body is longer than the first protruding length.

4. The energy storage device according to claim 2 or 3, wherein a plurality of the third protrusions are arranged on the spacer body in the second direction.

5. The electricity storage device according to any one of claims 1 to 3, wherein the first convex portion is formed by a thick portion of the spacer body.

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