Energy storage device, energy storage equipment and power system

Abstract

The invention discloses an energy storage device, energy storage equipment and a power system, the energy storage device comprises a middle shell, an end cover assembly, a first side shell, a second side shell and a battery cell, and the middle shell and a cover plate of the end cover assembly enclose a first space; the first side shell and the second side shell which are oppositely arranged at an interval are connected with the middle shell and the cover plate, at least one of the first side shell and the second side shell comprises a frame body and an elastic film, and the frame body is in a ring shape connected end to end and is connected with the middle shell and the cover plate; the elastic film comprises a main body part and an edge part, and the edge part is connected to the peripheral edge of the main body part; the frame body is provided with a mounting groove, an opening of the mounting groove faces the first space, the edge part extends into the mounting groove and is connected with the frame body, and the main body part protrudes in the direction away from the middle shell relative to the frame body; a second space communicated with the first space is enclosed by the main body part, the battery cell is accommodated in the first space and the second space, and the elastic film elastically abuts against the large surface of the battery cell. The energy storage device provides enough pre-tightening force for the battery cell, and the battery capacity can be improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an energy storage device, energy storage equipment and a power system. Background Art

[0002] Energy storage devices usually include structures such as a shell and a battery cell, and the battery cell is contained in the shell. The thickness of the battery cell will change when the energy storage device is assembled, formed, and subsequently used. However, the current energy storage device is a fixed structure, which cannot provide sufficient pre-tightening force to the battery cell and cannot meet the working requirements of the energy storage device. Summary of the invention

[0003] The purpose of this application is to provide an energy storage device, energy storage equipment and power system to solve the problem that the energy storage device cannot provide sufficient preload force to the battery cell and to increase the battery capacity.

[0004] To achieve the purpose of this application, this application provides the following technical solutions:

[0005] In a first aspect, the present application provides an energy storage device, including an intermediate shell, an end cover assembly, a first side shell, a second side shell and a battery cell, wherein the intermediate shell includes a bottom plate, a first side plate and a second side plate, wherein the first side plate and the second side plate are connected to the bottom plate, and the first side plate and the second side plate are both located on the same side of the bottom plate, and the first side plate and the second side plate are relatively spaced apart; the end cover assembly includes a cover plate, wherein the cover plate is connected to the first side plate and the second side plate and is opposite to the bottom plate, and the intermediate shell and the cover plate enclose a first space; the first side shell and the second side shell are all connected to the bottom plate, the first side plate, the second side plate and the cover plate, and the first side shell and the second side shell are relatively spaced apart; at least one of the first side shell and the second side shell includes a frame and an elastic membrane, and the frame is connected end to end The frame is in the shape of a ring, and the frame is connected to the bottom plate, the first side plate, the second side plate and the cover plate; the elastic membrane includes a main body and an edge portion, and the edge portion is connected to the four peripheral edges of the main body; the frame has a mounting groove, the opening of the mounting groove faces the first space, the edge portion extends into the mounting groove and is connected to the frame, and the main body protrudes relative to the frame in the direction away from the intermediate shell; the main body encloses a second space, and the second space is connected to the first space, and the battery cell is accommodated in the first space and the second space. In the cross section along the height direction of the energy storage device, the battery cell is a runway-type wound battery cell, or a rectangular stacked battery cell, the relative direction of the first side shell and the second side shell is the thickness direction of the battery cell, and the elastic membrane elastically abuts against the large surface of the battery cell.

[0006] The energy storage device of the embodiment of the present application is provided with at least one of the first side shell and the second side shell including a frame and an elastic membrane, and the main body of the elastic membrane protrudes from the side of the frame facing away from the middle shell and has a corner at the junction of the main body and the edge. In addition to being accommodated in the first space enclosed by the middle shell and the cover plate, the second space enclosed by the main body of the elastic membrane can also accommodate the battery cell, so that a larger volume of battery cells can be accommodated, which is beneficial to improving the battery capacity. Compared with the non-deformable structure of the side shell, the battery cell can have a larger expansion space when the thickness changes. At the same time, the deformation of the elastic membrane can provide tension to react on the large surface of the battery cell, thereby providing the battery cell with sufficient pre-tightening force to meet the working requirements of the energy storage device.

[0007] In one implementation, a minimum distance between the first side shell and the second side shell is smaller than a thickness of the battery cell.

[0008] By setting the minimum spacing between the first side shell and the second side shell to be smaller than the thickness of the battery cell, the battery cell is accommodated in the first space and the second space. After the first side shell, the middle shell and the second side shell are connected and fixed, the battery cell elastically abuts against the elastic membrane, and the deformation of the elastic membrane can provide sufficient pre-tightening force to the battery cell, thereby preventing the capacity of the battery cell from dropping significantly during the formation stage (the first charge and discharge cycle of the battery cell) and avoiding the battery cell capacity diving phenomenon.

[0009] In one embodiment, the mounting groove includes a snap-fit ​​groove and a connecting groove, the opening of the connecting groove connects the junction of the first space and the second space, the other end of the connecting groove connects the snap-fit ​​groove, and the spacing dimension between the two opposite inner wall surfaces of the snap-fit ​​groove is greater than the spacing dimension between the two opposite inner wall surfaces of the connecting groove;

[0010] The edge portion includes a body and a flange. The body is annular and the inner four edges are connected to the main body. The flange is connected to the outer four edges of the body. The thickness of the flange is greater than the thickness of the body. The flange is accommodated in the clamping groove, and at least part of the body is accommodated in the connecting groove.

[0011] By providing the installation groove including the clamping groove and the communicating groove, and the edge of the elastic membrane including the body and the flange, the elastic membrane and the frame can be connected with a simple structure, which is simple and easy to implement.

[0012] In one embodiment, the direction of the engaging groove toward the communicating groove has an angle with the opening direction of the communicating groove, and in the cross section of the elastic membrane, the body is bent, and an angle is formed between the body and the main body.

[0013] By setting the direction of the snap-in groove toward the connecting groove to have an angle with the opening direction of the connecting groove, the connecting groove is a non-uniform structure, and the inner wall of the connecting groove is connected with the bent body, the snap-in effect between the edge and the frame can be enhanced, and the elastic membrane is not easy to fall out of the frame.

[0014] In one embodiment, the frame body includes a first frame and a second frame, the first frame includes a first plate and a second plate, the first plate and the second plate are connected and form an "L" shape in the cross section of the frame body, the second frame is arranged on the surface of the first plate facing the battery cell, and on the side of the second plate facing the first plate, the second frame is connected to the end of the first plate away from the second plate, the second frame and the first plate enclose the clamping groove, the gap between the second frame and the first plate and the second plate forms the connecting groove, and the second frame and the second plate have a gap to form the opening of the connecting groove.

[0015] By setting the first frame to include the first plate and the second plate, the second frame and the first plate enclose the snap-in groove, and the gap between the second frame and the first plate and the second plate forms a connecting groove, a simple structure can be used to realize the installation of the frame and the elastic membrane, and provide a stable supporting foundation for the elastic membrane, and the structure is simple.

[0016] In one embodiment, the second frame includes a third plate, a fourth plate and a fifth plate connected in sequence, the third plate is connected to the first plate, the fourth plate is recessed in a direction away from the first plate, the fifth plate is spaced apart from the second plate, the fourth plate and the first plate jointly enclose the snap-in groove, and the fifth plate, the first plate and the second plate jointly enclose the connecting groove.

[0017] By setting the fourth plate of the second frame to be recessed in the direction away from the first plate to form a snap-in groove, the second frame forms a convex structure protruding toward one side of the battery cell, which can prevent the first frame located outside the battery cell relative to the second frame from warping due to the change in air pressure caused by the expansion of the battery cell.

[0018] In one embodiment, the second frame protrudes from an end of the first plate away from the second plate, and a portion of the second frame protruding from the first plate is connected to the intermediate shell and the cover plate.

[0019] Such an arrangement can make the entire outer shell surface of the energy storage device roughly a uniform structure, and the connection between the frame, the intermediate shell and the cover plate is relatively flat, not easy to collide with other parts, and is also more beautiful.

[0020] In one embodiment, the frame body includes a third frame and a fourth frame, the third frame is closer to the intermediate shell than the fourth frame, the third frame is connected to the intermediate shell and the cover plate, the third frame and the fourth frame are connected and jointly enclose the mounting groove, and the direction of the snap-in groove toward the connecting groove is on the same line as the opening direction of the connecting groove.

[0021] By setting the frame to include a third frame and a fourth frame, the third frame and the fourth frame are opposite and connected to form an installation groove, and the connecting groove of the installation groove is roughly a straight-line structure. The simple structure can realize the installation of the frame and the elastic membrane and provide a stable supporting foundation for the elastic membrane. The structure is simple.

[0022] In one embodiment, an end of the third frame away from the opening of the communicating groove protrudes from the fourth frame.

[0023] By arranging the opening end of the third frame away from the communicating groove to protrude from the fourth frame, the connection and assembly of the third frame and the fourth frame are facilitated.

[0024] In one embodiment, a step is provided at the junction of the end surface of the third frame away from the opening of the communicating groove and the surface of the third frame away from the fourth frame, and the intermediate shell and the cover plate are connected to the step.

[0025] By providing a step at the junction of the end surface of the third frame away from the opening of the connecting groove and the surface of the third frame away from the fourth frame, the third frame is conveniently connected and assembled with the intermediate shell and the cover plate at the step, and the outer surface of the entire energy storage device is relatively complete and uniform after assembly.

[0026] In one embodiment, in the cross section of the frame body, the frame body is in an "S" shape and includes a fifth frame, a first connecting frame, a sixth frame, a second connecting frame and a seventh frame connected in sequence, the fifth frame is opposite to the sixth frame, the first connecting frame connects the fifth frame and the sixth frame, the fifth frame, the first connecting frame and the sixth frame jointly enclose the mounting groove, and the direction of the snap-in groove toward the connecting groove is in the same straight line as the opening direction of the connecting groove, the second connecting frame is connected to the end of the sixth frame away from the first connecting frame, the seventh frame is arranged on the side of the sixth frame facing away from the fifth frame, the seventh frame is connected to the second connecting frame, and the seventh frame is connected to the intermediate shell and the cover plate.

[0027] By setting the frame body to include a fifth frame, a first connecting frame, a sixth frame, a second connecting frame and a seventh frame connected in sequence, the fifth frame, the first connecting frame and the sixth frame jointly enclose the installation groove, and the seventh frame is connected to the intermediate shell and the cover plate, the frame body can also be installed with an elastic membrane while the frame body is connected to the intermediate shell and the cover plate, and the structure is simple.

[0028] In one embodiment, the fifth frame, the first connecting frame and the sixth frame are all located in the first space, the seventh frame protrudes from the side of the first connecting frame facing away from the second connecting frame, and the portion of the seventh frame protruding from the first connecting frame is connected to the intermediate shell and the cover plate.

[0029] By arranging the seventh frame to protrude from the side of the first connecting frame facing away from the second connecting frame, it is convenient to connect the frame body with the intermediate shell and the cover plate.

[0030] In one implementation manner, the first connecting frame includes a first outer surface facing away from the fifth frame and the sixth frame, and the first outer surface is an arc surface.

[0031] By setting the first outer surface as an arc surface, when the intermediate shell and the cover plate are connected to the seventh frame, the first outer surface can guide the intermediate shell and the cover plate to ensure accurate positioning.

[0032] In one embodiment, the middle shell includes a main shell and a side shell, the side shell is connected to the edge of the main shell, and the side shell is bent toward the first space relative to the main shell; the side shell includes a connecting surface facing away from the first space, the frame is connected to the connecting surface, and the frame and the side shell jointly enclose the installation groove.

[0033] By setting the middle shell to include a side shell bent toward the first space relative to the main shell, the connecting surface of the side shell facing away from the first space and the frame together enclose the installation groove, the frame and the middle shell are connected while the elastic membrane is installed on the frame, and the structure is simple.

[0034] In one embodiment, the frame body includes an eighth frame and a ninth frame, the eighth frame is connected to the ninth frame and is in an "L" shape, the end of the eighth frame away from the ninth frame is connected to the connecting surface, the area of ​​the ninth frame close to the eighth frame is recessed to form the snap-in groove together with the connecting surface, and there is a gap between the area of ​​the ninth frame away from the eighth frame and the side shell to form the connecting groove.

[0035] By setting the frame body including the eighth frame and the ninth frame, a mounting groove is formed between the eighth frame, the ninth frame and the connecting surface, and a simple structure can be used to achieve installation with the elastic membrane and provide a stable supporting foundation for the elastic membrane, and the structure is simple.

[0036] In one embodiment, the end surface of the side shell away from the main shell is smoothly connected to the connecting surface, and there is a gap between the smoothly connected area and the ninth shell to form the connecting groove.

[0037] After installation, the body of the elastic membrane will contact the end face of the side shell away from the main shell. By arranging a smooth connection between the end face of the side shell away from the main shell and the connecting surface, the end of the side shell away from the main shell can avoid crushing the body of the elastic membrane, thereby improving the service life of the elastic membrane.

[0038] In one embodiment, the frame is chamfered at a position where the main body and the edge portion meet.

[0039] By providing a rounded corner at the position where the frame body corresponds to the main body and the edge portion, a shearing effect is avoided when the sharp corner structure at the joint contacts the elastic membrane, thereby increasing the service life of the elastic membrane.

[0040] In one embodiment, the inner wall surface of the intermediate shell is provided with a plurality of protrusions arranged at intervals.

[0041] By providing the inner wall surface of the intermediate shell with a plurality of protrusions arranged at intervals, the battery cells in the storage space can be positioned and limited, preventing the battery cells from moving around in the height and width directions, ensuring the accurate relative position of the battery cells and the elastic membrane, and thus making the elastic membrane elastically abut against the large surface of the battery cells.

[0042] In one embodiment, the end cover assembly further includes a one-way valve, which is disposed on the cover plate and is used to release pressure when the internal pressure of the energy storage device reaches a threshold value.

[0043] By providing the end cover assembly also including a one-way valve, the pressure can be released in time when the internal pressure of the energy storage device is too high, thereby ensuring the safety of the energy storage device.

[0044] In a second aspect, the present application further provides an energy storage device, comprising an energy storage device as described in any one of the various embodiments of the first aspect and a reinforcing plate, wherein the reinforcing plate is arranged on at least one side in the thickness direction of the energy storage device.

[0045] The energy storage device in the present application provides a reinforcing plate on at least one side in the thickness direction. In addition to the preload force provided by the elastic membrane, the reinforcing plate can provide additional preload force to the battery cell in the thickness direction of the battery cell, thereby meeting the working requirements of the energy storage device.

[0046] In one embodiment, there are multiple energy storage devices, and the multiple energy storage devices are arranged in sequence along the thickness direction; the reinforcing plate is arranged on the outermost side of the multiple energy storage devices as a whole in the thickness direction of the energy storage devices, and / or the reinforcing plate is arranged between two adjacent energy storage devices; at least one of the reinforcing plates is movable in the thickness direction of the energy storage device.

[0047] By arranging a reinforcing plate at the outermost sides of the multiple energy storage devices in the overall thickness direction, and / or arranging a reinforcing plate between two adjacent energy storage devices, in addition to the preload force provided by the elastic membrane, the reinforcing plate can provide additional preload force to the battery cell, thereby meeting the working requirements of the energy storage device and avoiding excessive expansion and deterioration of the battery cell.

[0048] In a third aspect, the present application further provides an electric power system, comprising an electric device and an energy storage device as described in any one of the various embodiments of the first aspect, wherein the energy storage device supplies power to the electric device; or an energy storage device as described in any one of the various embodiments of the second aspect, wherein the energy storage device supplies power to the electric device.

[0049] The power system in the present application adopts the energy storage device or energy storage equipment in the embodiment of the present application. The energy storage device or energy storage equipment can provide sufficient pre-tightening force to the battery cell to meet the working requirements of the energy storage device or energy storage equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 is a three-dimensional diagram of an energy storage device according to an embodiment;

[0052] Figure 2 is an exploded schematic diagram of an energy storage device according to an embodiment;

[0053] Figure 3 is a partial cross-sectional schematic diagram of an energy storage device according to an embodiment;

[0054] Figure 4 is a partial cross-sectional schematic diagram of an energy storage device in another embodiment;

[0055] Figure 5 is a partial cross-sectional schematic diagram of an energy storage device according to another embodiment;

[0056] Figure 6 It is a partial cross-sectional schematic diagram of an energy storage device according to another embodiment.

[0057] Description of reference numerals:

[0058] 100-Energy storage device;

[0059] 10-middle shell, 11-bottom plate, 12-first side plate, 13-second side plate, 14-protrusion, 15-main shell, 16-side shell, 161-connecting surface;

[0060] 20-end cover assembly, 21-cover plate, 22-connecting piece, 23-pole;

[0061] 31-first side shell, 32-second side shell, 33-frame, 331-installing groove, 3311-clamping groove, 3312-connecting groove, 332-first frame, 3321-first plate, 3322-second plate, 333-second frame, 3331-third plate, 3332-fourth plate, 3333-fifth plate, 334-third frame, 3341-step, 3342-step surface, 335-fourth frame, 34-elastic membrane, 341-main body, 3411-second space, 342-edge, 3421-main body, 3422-flange, 351-fifth frame, 352-first connecting frame, 3521-first outer surface, 353-sixth frame, 354-second connecting frame, 3541-second outer surface, 355-seventh frame, 361-eighth frame, 362-ninth frame;

[0062] 40-First space;

[0063] 50-battery cell;

[0064] X is the width direction of the energy storage device, Y is the thickness direction of the energy storage device, and Z is the height direction of the energy storage device. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0066] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0067] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application and in the specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this application includes any and all combinations of one or more of the related listed items.

[0068] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0069] Please refer to Figure 1 and Figure 2 The present application provides an energy storage device 100, including an intermediate shell 10, an end cover assembly 20, a first side shell 31, a second side shell 32 and a battery cell 50. The overall shape of the energy storage device 100 after assembly is roughly a rectangular parallelepiped. For the convenience of description, the XYZ direction is defined, where the X direction is the width direction of the energy storage device 100, the Y direction is the thickness direction of the energy storage device 100, and the Z direction is the height direction of the energy storage device 100.

[0070] The middle shell 10 includes a bottom plate 11, a first side plate 12 and a second side plate 13. The first side plate 12 and the second side plate 13 are connected to the bottom plate 11, and the first side plate 12 and the second side plate 13 are both located on the same side of the bottom plate 11, and the first side plate 12 and the second side plate 13 are relatively spaced apart.

[0071] The bottom plate 11, the first side plate 12 and the second side plate 13 are all roughly flat plates. The bottom plate 11 extends in the X direction. The first side plate 12 and the second side plate 13 are respectively connected to the two side edges of the bottom plate 11 in the X direction. The first side plate 12 and the second side plate 13 extend in the Z direction. The intermediate shell 10 can be an integrated structure, that is, the bottom plate 11, the first side plate 12 and the second side plate 13 are an integrated structure. For example, the intermediate shell 10 can be formed by bending a long plate, or by other processes, without limitation. The intermediate shell 10 can also be connected and fixed by welding, screwing, riveting and other processes.

[0072] The end cover assembly 20 includes a cover plate 21, which is connected to the first side plate 12 and the second side plate 13 and is opposite to the bottom plate 11. The cover plate 21 can be made of aluminum, steel, etc. The cover plate 21 made of aluminum is generally called a plain aluminum sheet. The cover plate 21 is also roughly flat and extends along the X direction. The two end edges of the cover plate 21 in the X direction are respectively connected to the first side plate 12 and the second side plate 13, and the connection method can be welding, screwing, riveting, etc. The material of the first side plate 12 and the second side plate 13 can be aluminum, carbon steel (such as model SPCC), stainless steel (model SUS304, SUS316, etc.), without limitation.

[0073] The end cap assembly 20 also includes an insulating member (not shown), a pole 23, a connecting piece 22, a top patch (not shown), etc. The insulating member is arranged on the surface of the cover plate 21 facing the bottom plate 11, and the cover plate 21 and the insulating member are provided with holes, and the pole 23 passes through the hole, so that one end of the pole 23 is located at the insulating member and the other end extends out of the cover plate 21. The connecting piece 22 connects the end of the pole 23 located at the insulating member and the pole ear of the battery cell 50. The top patch is attached to the surface of the cover plate 21 facing away from the bottom plate 11, and the pole 23 is exposed. The connecting piece 22 and the pole 23 are used to transmit electric energy, the insulating member is used to separate the connecting piece 22 and the cover plate 21 to avoid short circuit, and the top patch plays an insulating protection role. Positive and negative terminals can be provided on one end cap assembly 20 at the same time, specifically, the pole 23 includes a positive pole 23 and a negative pole 23, the connecting piece 22 includes a positive connecting piece 22 and a negative connecting piece 22, the positive pole 23 and the negative pole 23 are arranged at intervals on the same cover plate 21, the positive connecting piece 22 is connected to the positive pole 23 and the positive pole ear, and the negative connecting piece 22 is connected to the negative pole 23 and the negative pole ear. The specific structure of the end cap assembly 20 can refer to any feasible solution, and the embodiment of the present application is not limited.

[0074] The first side shell 31 and the second side shell 32 are connected to the bottom plate 11 , the first side plate 12 , the second side plate 13 and the cover plate 21 , and the first side shell 31 and the second side shell 32 are arranged relatively spaced apart.

[0075] The first side shell 31 and the second side shell 32 are roughly plate-shaped. The first side shell 31 and the second side shell 32 are relatively spaced apart in the Y direction. The first side shell 31 and the second side shell 32 are respectively connected to the middle shell 10 and the cover plate 21 at both side edges in the Y direction, thereby jointly enclosing a storage space.

[0076] In the embodiment of the present application, at least one of the first side shell 31 and the second side shell 32 includes a frame 33 and an elastic membrane 34. One of the first side shell 31 and the second side shell 32 may include a frame 33 and an elastic membrane 34, and the other may be only a flat plate. The flat plate side shell may be an integrated structure with the middle shell 10, or may be connected and fixed to the middle shell 10 by welding, screwing, riveting, etc. The first side shell 31 and the second side shell 32 may also both include a frame 33 and an elastic membrane 34, and the structures of the two are basically the same.

[0077] Among them, the frame 33 serves as a supporting base, and the elastic membrane 34 is installed on the frame 33. The frame 33 can be made of metal, which can be the same as or different from the material of the intermediate shell 10 and the cover plate 21. The material of the frame 33 can be AL3003 (aluminum alloy with manganese as the main alloy element), SPCC (cold-rolled carbon steel sheet), Sus304 (304 stainless steel), etc. The elastic membrane 34 is made of elastic material, which can provide elastic tension after deformation and has the ability to recover as before. At the same time, the elastic membrane 34 also has the performance of resisting corrosion of electrolyte. The specific material of the elastic membrane 34 can be EPDN (ethylene propylene diene monomer rubber), fluorine rubber, PFA (tetrafluoroethylene-perfluoroalkoxy vinyl ether copolymer), etc.

[0078] Please refer to Figure 2 and Figure 3 The frame body 33 is in a ring shape with the ends connected, and the frame body 33 is connected to the bottom plate 11 , the first side plate 12 , the second side plate 13 and the cover plate 21 .

[0079] The frame 33 is roughly formed into a "mouth" shaped structure, which includes four frames extending roughly in a straight line. The four frames are sequentially connected end to end to form a ring, and the adjacent frames are roughly perpendicular to each other. The four frames are roughly located in the same plane. The four frames are connected to the bottom plate 11, the first side plate 12, the second side plate 13 and the cover plate 21 in a one-to-one correspondence. The connection method can be welding, screwing, riveting, etc., without limitation.

[0080] refer to Figure 3 The elastic membrane 34 includes a main body 341 and an edge 342. The edge 342 is connected to the four edges of the main body 341 and has a corner at the junction of the main body 341 and the edge 342. The frame 33 has a mounting groove 331. The opening of the mounting groove 331 faces the first space 40. The edge 342 extends into the mounting groove 331 and is connected to the frame 33. The main body 341 protrudes in a direction away from the intermediate shell 10 relative to the frame 33. The intermediate shell 10 and the cover plate 21 enclose the first space 40. The main body 341 encloses a second space 3411. The second space 3411 is connected to the first space 40.

[0081] The elastic membrane 34 may be an integral structure, for example, the main body 341 and the edge 342 are an integral structure formed by injection molding. The elastic membrane 34 may also be a split structure connected to form a whole, for example, the main body 341 and the edge 342 may be connected to form a whole by bonding, hot-melt connection, etc.

[0082] The shape of the main body 341 when flattened matches the shape of the space enclosed by the frame 33, that is, the main body 341 is roughly rectangular when flattened, and its thickness direction is the Y direction. The edge portion 342 is connected to the mounting groove 331 of the frame 33 by a snap connection or any other feasible connection method such as bonding, without limitation.

[0083] The battery cell 50 is accommodated in the first space 40 and the second space 3411. The battery cell 50 is also roughly in the shape of a rectangular parallelepiped, and its width, thickness and height directions are the same as the corresponding directions of the aforementioned energy storage device 100. The battery cell 50 may include a bare battery cell 50, a pole ear, a Mylar film, etc. The bare battery cell 50 is connected to a pole ear at one end facing the end cover assembly 20, and the pole ear is connected to the aforementioned connecting piece 22. The pole ear includes a positive pole ear and a negative pole ear, both of which can be arranged at the same end to be connected to the same end cover assembly 20. The Mylar film is coated on the other surfaces of the bare battery cell 50 except the end face facing the top cover. The Mylar film plays a role in protecting the bare battery cell 50. The battery cell 50 may include one or more bare batteries 50. When there are multiple bare batteries 50, the multiple bare batteries 50 are arranged side by side and connected to the same end cover assembly 20. The specific structure of the battery cell 50 can refer to any feasible scheme, and the embodiment of the present application is not limited.

[0084] The battery cell 50 is a wound battery cell 50, and in the cross section along the Z direction (i.e., the cross section is perpendicular to the Z direction), the cross section of the battery cell 50 is a racetrack shape; or, the battery cell 50 is a stacked battery cell 50, and in the cross section along the Z direction, the cross section of the battery cell 50 is a rectangular. All of the above methods are possible and there is no specific limitation.

[0085] Combination Figure 2 The large surface of the battery cell 50 is any one of the two opposite surfaces of the battery cell 50 in the Y direction. When the battery cell 50 expands, it mainly expands in the Y direction, and the expansion in the X direction and the Z direction is relatively small. Wherein, before the energy storage device 100 is assembled and formed, the elastic film 34 elastically abuts against the large surface of the battery cell 50. And / or, when the energy storage device 100 is in a fully discharged state, the elastic film 34 elastically abuts against the large surface of the battery cell 50.

[0086] When the battery cell 50 expands in the Y direction, the edge portion 342 of the elastic membrane 34 is connected and fixed to the frame 33, and the battery cell 50 can expand in the first space 40 and the second space 3411 enclosed by the middle shell 10, the cover plate 21, the first side shell 31 and the second side shell 32, and can further expand to the side of the frame 33 facing away from the middle shell 10. The battery cell 50 squeezes the elastic membrane 34 so that the part of the elastic membrane 34 that contacts the large surface of the battery cell 50 is deformed outward in the Y direction. The tension of the deformation of the elastic membrane 34 applies an inward pulling force to the battery cell 50 in the Y direction, thereby providing a pre-tightening force to the battery cell 50.

[0087] Please refer to Figure 1 and Figure 2Taking the structure in which the first side shell 31 includes a frame 33 and an elastic membrane 34 and the second side shell 32 is a flat plate as an example, the assembly process of the energy storage device 100 is roughly as follows: the end cover assembly 20 is connected to the battery cell 50, specifically, the pole 23 is connected to the pole ear through the connecting piece 22. When the battery cell 50 has two bare battery cells 50, the two bare battery cells 50 can be laid flat on the same plane to connect with the end cover assembly 20, and then the two bare battery cells 50 are closed. Specifically, the core is to merge two flat bare cells 50 into a whole side by side along the Y direction and wrap them with hot-melt Mylar film; then the cell 50 and the end cover assembly 20 are installed into the middle shell 10, and the cover plate 21 of the end cover assembly 20 is connected to the middle shell 10; then the first side shell 31 and the second side shell 32 are installed; finally, the outer side of the middle shell 10, the first side shell 31 and the second side shell 32 can be coated with an outer film, and a top patch is attached to the cover plate 21, and the outer film plays a protective role.

[0088] In summary, the energy storage device 100 of the embodiment of the present application is provided with at least one of the first side shell 31 and the second side shell 32 including a frame 33 and an elastic membrane 34, and the main body 341 of the elastic membrane 34 protrudes from the side of the frame 33 facing away from the middle shell 10, and the main body 341 and the edge 342 have a corner. In addition to being accommodated in the first space 40 enclosed by the middle shell 10 and the cover plate 21, the second space 3411 enclosed by the main body 341 of the elastic membrane 34 can also accommodate the battery cell 50, so that a larger volume of battery cell 50 can be accommodated, which is beneficial to improving the battery capacity. Compared with the side shell having a non-deformable structure, the battery cell 50 can have a larger expansion space when the thickness changes. At the same time, the deformation of the elastic membrane 34 can provide tension to react on the large surface of the battery cell 50, thereby providing the battery cell 50 with sufficient pre-tightening force to meet the working requirements of the energy storage device 100.

[0089] In one embodiment, please refer to Figure 2 and Figure 3 , the minimum distance between the first side shell 31 and the second side shell 32 is smaller than the thickness of the battery cell 50 .

[0090] The first side shell 31 and the second side shell 32 are opposite to each other in the Y direction, so the minimum spacing between the first side shell 31 and the second side shell 32 is the minimum spacing between the first side shell 31 and the second side shell 32 in the Y direction. Since the elastic membrane 34 protrudes in the direction away from the intermediate shell 10 relative to the frame 33, the minimum spacing is the spacing between the frames 33 of the first side shell 31 and the second side shell 32. Optionally, when one of the first side shell 31 and the second side shell 32 includes the frame 33 and the elastic membrane 34, and the other is only a flat plate, the minimum spacing is the distance from the frame 33 of one to the flat plate of the other. When both the first side shell 31 and the second side shell 32 include the frame 33 and the elastic membrane 34, the minimum spacing is the distance between the frame 33 of the first side shell 31 and the frame 33 of the second side shell 32.

[0091] The minimum spacing between the first side shell 31 and the second side shell 32 is smaller than the size of the battery cell 50 in the Y direction (i.e., the thickness of the battery cell 50). When the battery cell 50 is assembled to the middle shell 10, the battery cell 50 has already protruded from the middle shell 10 in the Y direction. After the first side shell 31 and the second side shell 32 are assembled, the battery cell 50 protruding from the middle shell 10 lifts up the elastic membrane 34, so that the elastic membrane 34 is elastically deformed and applies sufficient pre-tightening force to the battery cell 50.

[0092] Optionally, the minimum spacing between the first side shell 31 and the second side shell 32 may be the same as the size of the middle shell 10 in the Y direction, or may be slightly larger or smaller than the size of the middle shell 10 in the Y direction, and there is no specific limitation.

[0093] By setting the minimum spacing between the first side shell 31 and the second side shell 32 to be smaller than the thickness of the battery cell 50, the battery cell 50 is accommodated in the first space 40 and the second space 3411. After the first side shell 31, the middle shell 10 and the second side shell 32 are connected and fixed, the battery cell 50 elastically abuts against the elastic membrane 34, and the deformation energy of the elastic membrane 34 can provide sufficient pre-tightening force to the battery cell 50, thereby preventing the capacity of the battery cell 50 from decreasing significantly during the formation stage (the first charge and discharge cycle of the battery cell 50) and avoiding the capacity diving phenomenon of the battery cell 50.

[0094] In one embodiment, reference Figure 3 The mounting groove 331 includes a snap-in groove 3311 and a connecting groove 3312. The opening of the connecting groove 3312 connects the junction of the first space 40 and the second space 3411. The other end of the connecting groove 3312 connects to the snap-in groove 3311. The spacing dimension between the two opposite inner wall surfaces of the snap-in groove 3311 is greater than the spacing dimension between the two opposite inner wall surfaces of the connecting groove 3312.

[0095] The edge portion 342 includes a main body 3421 and a flange 3422. The main body 3421 is annular and the inner four edges are connected to the main body 341. The flange 3422 is connected to the outer four edges of the main body 3421. The thickness of the flange 3422 is greater than the thickness of the main body 3421. The flange 3422 is accommodated in the snap-in groove 3311, and at least part of the main body 3421 is accommodated in the connecting groove 3312.

[0096] In this embodiment, the two opposite inner wall surfaces of the clamping groove 3311 may extend in the Y direction, or may have a certain angle with the Y direction. Exemplarily, the two opposite inner wall surfaces of the clamping groove 3311 extend in the Y direction, and at the connection between the frame 33 and the bottom plate 11 and the cover plate 21, the spacing dimension of the two opposite inner wall surfaces of the clamping groove 3311 refers to the dimension in the Z direction; at the connection between the frame 33 and the first side plate 12 and the second side plate 13, the spacing dimension of the two opposite inner wall surfaces of the clamping groove 3311 refers to the dimension in the X direction.

[0097] The gap size of the clamping groove 3311 is larger to accommodate the thicker flange 3422. The gap size of the connecting groove 3312 is smaller to accommodate at least part of the body 3421, and the other part of the body 3421 is accommodated at the junction of the first space 40 and the second space 3411. The thickness of the flange 3422 is larger than the gap size of the connecting groove 3312, so that the flange 3422 cannot exit through the connecting groove 3312.

[0098] Optionally, the thickness of the body 3421 is 0.1mm-2mm, specifically 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc., without limitation. Optionally, the thickness of the flange 3422 is 0.1mm-3mm thicker than the thickness of the body 3421. In a specific embodiment, the thickness of the body 3421 is 0.4mm, and the thickness of the flange 3422 is 0.6mm.

[0099] The edge portion 342 may be an integral structure, for example, the body 3421 and the flange 3422 may be an integral structure formed by injection molding. The edge portion 342 may also be a split structure formed as a whole by connection, for example, the body 3421 and the flange 3422 may be formed as a whole by bonding, hot-melt connection, etc.

[0100] The mounting groove 331 is used for snap-fitting connection with the edge portion 342 of the elastic membrane 34, that is, after the flange 3422 is accommodated in the snap-fitting groove 3311 and at least a portion of the main body 3421 is accommodated in the connecting groove, the elastic membrane 34 pulls the flange 3422 when deformed, and the flange 3422 will snap-fit ​​with the side wall of the connecting groove 3312 toward the opening of the snap-fitting groove 3311 and will not withdraw through the connecting groove 3312, thereby realizing the snap-fit ​​connection between the elastic membrane 34 and the frame 33.

[0101] By providing the installation groove 331 including the snap-in groove 3311 and the connecting groove 3312 , and the edge portion 342 of the elastic membrane 34 including the body 3421 and the flange 3422 , the elastic membrane 34 and the frame 33 can be connected with a simple structure, which is simple and easy to implement.

[0102] In one embodiment, reference Figure 3 The direction of the snap-in groove 3311 toward the connecting groove 3312 has an angle with the opening direction of the connecting groove 3312 . In the cross section of the elastic membrane 34 , the main body 3421 is bent, and an angle is formed between the main body 3421 and the main body 341 .

[0103] Optionally, the angle between the direction of the snap-in groove 3311 toward the connecting groove 3312 and the opening direction of the connecting groove 3312 can be 60°-100°, specifically 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, etc., without limitation.

[0104] Optionally, the inner wall of the connecting groove 3312 is bent, which may be bent once or multiple times, and there is no specific limitation. Since at least part of the body 3421 is accommodated in the connecting groove 3312, one end of the body 3421 is connected to the main body 341, and the other end is connected to the flange 3422, the body 3421 is also bent, and the bending shape of the body 3421 corresponds to the shape of the inner wall of the connecting groove 3312.

[0105] Optionally, in the cross section of the elastic membrane 34, the main body 341 and the main body 3421 have an angle at their junction, and the angle may be 60°-110°, specifically 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, etc., without limitation. The angle between the direction of the clamping groove 3311 toward the connecting groove 3312 and the opening direction of the connecting groove 3312 and the angle between the main body 341 and the main body 3421 may be the same or different, without limitation.

[0106] By setting the direction of the snap-in groove 3311 toward the connecting groove 3312 to have an angle with the opening direction of the connecting groove 3312, the connecting groove 3312 is a non-uniform structure, and the inner wall of the connecting groove 3312 is matched and connected with the bent main body 3421, which can enhance the snap-in effect between the edge portion 342 and the frame 33, and the elastic membrane 34 is not easy to fall off from the frame 33.

[0107] In one embodiment, reference Figure 3 The frame body 33 includes a first frame 332 and a second frame 333. The first frame 332 includes a first plate 3321 and a second plate 3322. The first plate 3321 and the second plate 3322 are connected and form an "L" shape in the cross section of the frame body 33. The second frame 333 is arranged on the surface of the first plate 3321 facing the battery cell 50, and on the side of the second plate 3322 facing the first plate 3321. The second frame 333 is connected to an end of the first plate 3321 away from the second plate 3322. The second frame 333 and the first plate 3321 enclose a snap-in groove 3311. The gap between the second frame 333 and the first plate 3321 and the second plate 3322 forms a connecting groove 3312. There is a gap between the second frame 333 and the second plate 3322 to form an opening of the connecting groove 3312.

[0108] The first frame 332 and the second frame 333 may both be in the form of a ring connected end to end along the circumferential direction of the frame body 33 , or one or both of them may be a multi-segment structure sequentially arranged along the circumferential direction, without limitation.

[0109] The first plate 3321 protrudes from the side of the second plate 3322 facing the battery cell 50. There is an angle between the first plate 3321 and the second plate 3322, which is the same as the angle between the direction of the aforementioned snap-in groove 3311 toward the connecting groove 3312 and the opening direction of the connecting groove 3312. In one embodiment, the angle between the first plate 3321 and the second plate 3322 is 90°, the first plate 3321 extends roughly along the Y direction, and the second plate 3322 extends roughly along the Z direction (where the frame 33 is connected with the bottom plate 11 and the cover plate 21) or the X direction (where the frame 33 is connected with the first side plate 12 and the second side plate 13), and the first plate 3321 and the second plate 3322 are "L" shaped in the cross section of the frame 33.

[0110] Taking the connection between the frame body 33 and the cover plate 21 as an example, one of the first frame 332 and the second frame 333 may be recessed to form a snap-on groove 3311, and correspondingly, the flange 3422 of the edge portion 342 protrudes from one side surface of the body 3421 in the Z direction to correspond to the snap-on groove 3311. Alternatively, both the first frame 332 and the second frame 333 may be recessed to form a snap-on groove 3311, and correspondingly, the flange 3422 protrudes from both side surfaces of the body 3421 in the Z direction to correspond to the snap-on groove 3311.

[0111] Optionally, the first frame 332 may be an integrated structure, that is, the first plate 3321 and the second plate 3322 are an integrated structure made by an integrated molding process. The first frame 332 may also be a split structure, and the first plate 3321 and the second plate 3322 are formed as a whole by welding, screwing, clamping, riveting, etc., without limitation. Optionally, the surfaces of the first plate 3321 and the second plate 3322 facing away from the second frame 333 are smoothly connected.

[0112] Optionally, the first frame 332 and the second frame 333 may be an integrated structure, and the assembly method of the whole with the elastic membrane 34 may be achieved by bending one of the first frame 332 and the second frame 333. Alternatively, the first frame 332 and the second frame 333 are split structures, and the second frame 333 and the end of the first plate 3321 away from the second plate 3322 are formed as a whole by welding, screwing, clamping, riveting, etc., without limitation.

[0113] Take the connection between the frame 33 and the cover plate 21 as an example, Figure 3The second frame 333 is spaced apart from the first plate 3321 in the Z direction, and the second frame 333 is spaced apart from the second plate 3322 in the Y direction. The two are connected and together form a connecting groove 3312 to accommodate the body 3421 of the elastic membrane 34 .

[0114] By setting the first frame 332 to include the first plate 3321 and the second plate 3322, the second frame 333 and the first plate 3321 enclose the snap-in groove 3311, and the gap between the second frame 333 and the first plate 3321 and the second plate 3322 forms a connecting groove 3312. The simple structure can realize the installation of the frame 33 and the elastic membrane 34 and provide a stable supporting foundation for the elastic membrane 34. The structure is simple.

[0115] In one embodiment, please refer to Figure 3 The second frame 333 includes a third plate 3331, a fourth plate 3332 and a fifth plate 3333 which are connected in sequence, the third plate 3331 is connected to the first plate 3321, the fourth plate 3332 is recessed in a direction away from the first plate 3321, the fifth plate 3333 and the second plate 3322 are spaced apart, the fourth plate 3332 and the first plate 3321 jointly enclose the snap-in groove 3311, and the fifth plate 3333, the first plate 3321 and the second plate 3322 jointly enclose the connecting groove 3312.

[0116] The second frame 333 can be an integrated structure, that is, the third plate 3331, the fourth plate 3332 and the fifth plate 3333 are an integrated structure made by an integrated molding process. The third plate 3331, the fourth plate 3332 and the fifth plate 3333 can also be an integrated structure in which two of them are integrated and formed into a whole with the third through welding, screwing, clamping, etc., or the three can be independent and formed into a whole through welding, screwing, clamping, riveting, etc., all without limitation. When assembling with the elastic membrane 34, the flange 3422 can be first placed in the clamping groove 3311 enclosed by the fourth plate 3332 and the first plate 3321, and then the third plate 3331 and the first plate 3321 are connected.

[0117] The third plate 3331 and the first plate 3321 can be connected by welding, screwing, clamping, riveting, etc., without limitation. The fifth plate 3333 and the first plate 3321 enclose the connection between the connection groove and the clamping groove 3311, and the fifth plate 3333 and the second plate 3322 enclose the other part of the connection groove and the opening of the connection groove.

[0118] Optionally, the cross-sectional shape of the fourth plate 3332 may be trapezoidal, semicircular, rectangular, etc., without specific limitation.

[0119] By setting the fourth plate 3332 of the second frame 333 to be recessed in a direction away from the first plate 3321 to form a snap-in groove 3311, the second frame 333 forms a convex structure protruding toward one side of the battery cell 50, which can prevent the first frame 332 located on the outside of the battery cell 50 relative to the second frame 333 from warping up due to the change in air pressure caused by the expansion of the battery cell 50.

[0120] In one embodiment, reference Figure 3 The second frame 333 protrudes from one end of the first plate 3321 away from the second plate 3322 , and the portion of the second frame 333 protruding from the first plate 3321 is connected to the middle shell 10 and the cover plate 21 .

[0121] In the Y direction, the second frame 333 protrudes from the end of the first plate 3321 away from the second plate 3322, that is, the end of the second frame 333 facing the battery cell 50 is closer to the battery cell 50 than the first frame 332. In this way, the second frame 333 has an installation position exposed from the first frame 332 in a direction perpendicular to the Y direction, and the intermediate shell 10 and the cover plate 21 can be connected and fixed to the second frame 333 at this installation position, and the connection method can be welding, screw connection, clamping, riveting, etc., without limitation.

[0122] Further, the thickness of the connection between the middle shell 10 and the cover plate 21 and the second frame 333 is substantially the same as the thickness of the first plate 3321. The thickness of the first side plate 12 and the second side plate 13 of the middle shell 10 is the size thereof in the X direction, and the thickness of the bottom plate 11 and the cover plate 21 of the middle shell 10 is the size thereof in the Z direction.

[0123] With such an arrangement, the entire outer shell surface of the energy storage device 100 can be roughly a uniform structure, and the connection between the frame 33, the intermediate shell 10 and the cover plate 21 is relatively flat, not easy to collide with other parts, and is also more beautiful.

[0124] In another embodiment, reference Figure 4 The frame body 33 includes a third frame 334 and a fourth frame 335. The third frame 334 is closer to the middle shell 10 than the fourth frame 335. The third frame 334 is connected to the middle shell 10 and the cover plate 21. The third frame 334 and the fourth frame 335 are connected and jointly enclose the mounting groove 331, and the direction of the snap-in groove 3311 toward the connecting groove 3312 is on the same straight line as the opening direction of the connecting groove 3312.

[0125] The third frame 334 and the fourth frame 335 may both be in a ring shape connected end to end along the ring direction of the frame body 33, or one or both of them may be a multi-stage structure sequentially arranged along the ring direction, without limitation. In a cross section at any position of the frame body 33, the third frame 334 and the fourth frame 335 generally form a "C"-shaped structure, and the two together enclose the installation groove 331.

[0126] One of the third frame 334 and the fourth frame 335 may be recessed to form the snap-in groove 3311, and correspondingly, the flange 3422 of the elastic membrane 34 protrudes from one side surface of the body 3421 in the Y direction to correspond to the snap-in groove 3311. Alternatively, both the third frame 334 and the fourth frame 335 may be recessed to form the snap-in groove 3311, and correspondingly, the flange 3422 protrudes from both side surfaces of the body 3421 in the Y direction to correspond to the snap-in groove 3311.

[0127] Optionally, the third frame 334 and the fourth frame 335 may be an integrated structure, and the assembly of the overall "C"-shaped structure and the elastic membrane 34 may be achieved by bending one of the third frame 334 and the fourth frame 335. Specifically, an intermediate member is first manufactured, the shape of the intermediate member in the cross section at any position is "L"-shaped, and a concave is pre-formed on the surface near the junction of the two sections of the "L"-shaped structure, and then the flange 3422 of the elastic membrane 34 is placed in one of the concave sections, and then one of the two sections of the "L"-shaped structure is bent to form a "C"-shaped structure, and the pre-formed concave sections are opposite to each other and form a snap-on groove 3311.

[0128] Optionally, the third frame 334 and the fourth frame 335 may also be a split structure, where one end of the third frame 334 away from the battery cell 50 is connected and fixed to the fourth frame 335, and there is a gap between one end of the third frame 334 facing the battery cell 50 and one end of the fourth frame 335 facing the battery cell 50 to form a connecting groove 3312.

[0129] The open end of the third frame 334 away from the connecting groove 3312 can be flush with the fourth frame 335, or the open end of the third frame 334 away from the connecting groove 3312 protrudes from the fourth frame 335, or the fourth frame 335 protrudes from the open end of the third frame 334 away from the connecting groove 3312. All of the above methods are possible and are not specifically limited.

[0130] Optionally, the middle shell 10 and the cover plate 21 may be connected and fixed to the third frame 334 at a side of the third frame 334 facing away from the fourth frame 335 , and the connection method may be welding, screwing, clamping, riveting, etc., without limitation.

[0131] By setting the frame 33 to include a third frame 334 and a fourth frame 335, the third frame 334 and the fourth frame 335 are opposite and connected to form a mounting groove 331, and the connecting groove 3312 of the mounting groove 331 is roughly a straight-line structure. The simple structure can realize the installation of the frame 33 and the elastic membrane 34 and provide a stable supporting foundation for the elastic membrane 34, and the structure is simple.

[0132] In one embodiment, reference Figure 4 , an opening end of the third frame 334 away from the connecting groove 3312 protrudes from the fourth frame 335 .

[0133] Optionally, the third frame 334 and the fourth frame 335 may be connected by welding, screwing, riveting, etc., without limitation. Exemplarily, the opening end of the third frame 334 away from the connecting groove 3312 is welded and fixed to the fourth frame 335, and the opening end of the third frame 334 away from the connecting groove 3312 protrudes from the fourth frame 335, thereby providing a welding position, facilitating the welding operation, and the molten metal after welding will not flow into the mounting groove 331, thereby preventing the high temperature from affecting the elastic membrane 34.

[0134] By arranging the opening end of the third frame 334 away from the communicating groove 3312 to protrude from the fourth frame 335 , the connection and assembly of the third frame 334 and the fourth frame 335 are facilitated.

[0135] In one embodiment, reference Figure 4 A step 3341 is provided at the junction of the end surface of the third frame 334 away from the opening of the communicating groove 3312 and the surface of the third frame 334 away from the fourth frame 335 , and the intermediate shell 10 and the cover plate 21 are connected to the step 3341 .

[0136] The step 3341 includes a step surface 3342, which is a plane recessed from the surface of the third frame 334 facing away from the fourth frame 335. The step surface 3342 is connected to the end surface of the third frame 334 away from the opening of the connecting groove 3312. The step surface 3342 can be roughly parallel to the surface of the third frame 334 facing away from the fourth frame 335, or can have a certain angle, without limitation. The side wall of the step 3341 connects the step surface 3342 and the surface of the third frame 334 facing away from the fourth frame 335.

[0137] In this configuration, the intermediate shell 10 and the cover plate 21 are connected to the step 3341, specifically to the step surface 3342. The side wall of the step 3341 can position and limit the intermediate shell 10 and the cover plate 21. The surfaces of the intermediate shell 10 and the cover plate 21 away from the battery cell 50 can be roughly flush with the end surface of the third frame 334 away from the opening of the connecting groove 3312, and the outer surface of the entire energy storage device 100 is relatively complete and uniform.

[0138] Optionally, the step 3341 can be connected to the intermediate shell 10 and the cover plate 21 by welding, screwing, riveting, etc., without limitation. Exemplarily, the step 3341 is fixed to the intermediate shell 10 and the cover plate 21 by welding. The step 3341 provides a welding position, which can facilitate the welding operation, and the molten metal after welding will not flow into the mounting groove 331, so as to avoid the high temperature affecting the elastic membrane 34.

[0139] By providing a step 3341 at the junction of the end surface of the third frame 334 away from the opening of the connecting groove 3312 and the surface of the third frame 334 away from the fourth frame 335, the third frame 334 is conveniently connected and assembled with the intermediate shell 10 and the cover plate 21 at the step 3341, and the outer surface of the entire energy storage device 100 is relatively complete and uniform after assembly.

[0140] In another embodiment, referring to Figure 5 In the cross section of the frame body 33, the frame body 33 is in an "S" shape and includes a fifth frame 351, a first connecting frame 352, a sixth frame 353, a second connecting frame 354 and a seventh frame 355 connected in sequence, the fifth frame 351 is opposite to the sixth frame 353, the first connecting frame 352 connects the fifth frame 351 and the sixth frame 353, the fifth frame 351, the first connecting frame 352 and the sixth frame 353 jointly enclose the mounting groove 331, and the direction of the clamping groove 3311 toward the connecting groove 3312 is in the same straight line as the opening direction of the connecting groove 3312, the second connecting frame 354 is connected to the end of the sixth frame 353 away from the first connecting frame 352, the seventh frame 355 is arranged on the side of the sixth frame 353 facing away from the fifth frame 351, the seventh frame 355 is connected to the second connecting frame 354, and the seventh frame 355 is connected to the intermediate shell 10 and the cover plate 21.

[0141] Optionally, the fifth frame 351, the first connection frame 352, the sixth frame 353, the second connection frame 354 and the seventh frame 355 may be an integrated structure made by an integrated molding process. The fifth frame 351, the first connection frame 352, the sixth frame 353, the second connection frame 354 and the seventh frame 355 may also be any two or more of which are integrated structures and are formed as a whole with the rest by welding, screwing, clamping, etc., or the five may be independent and formed as a whole by welding, screwing, clamping, etc., without limitation.

[0142] The fifth frame 351, the first connection frame 352, the sixth frame 353, the second connection frame 354 and the seventh frame 355 can all be in a ring shape connected end to end along the ring direction of the frame body 33, or one or more of them can be a multi-stage structure arranged in sequence along the ring direction, without limitation. In the cross section at any position of the frame body 33, the fifth frame 351, the sixth frame 353 and the first connection frame 352 roughly form a "C"-shaped structure, and the three together enclose the installation groove 331, the direction of the clamping groove 3311 toward the connecting groove 3312 is on the same line as the opening direction of the connecting groove 3312, and the opening of the clamping groove 3311 faces the battery cell 50.

[0143] One of the fifth frame 351 and the sixth frame 353 may be recessed to form the snap-fit ​​groove 3311, and correspondingly, the flange 3422 of the elastic membrane 34 protrudes from one side surface of the body 3421 in the Y direction to correspond to the snap-fit ​​groove 3311. Alternatively, both the fifth frame 351 and the sixth frame 353 may be recessed to form the snap-fit ​​groove 3311, and correspondingly, the flange 3422 protrudes from both side surfaces of the body 3421 in the Y direction to correspond to the snap-fit ​​groove 3311.

[0144] In the cross section at any position of the frame body 33, the sixth frame 353, the second connection frame 354 and the seventh frame 355 also roughly form a "C"-shaped structure, and the opening direction of the "C"-shaped structure is opposite to the "C"-shaped structure roughly formed by the fifth frame 351, the sixth frame 353 and the first connection frame 352. In the cross section at any position of the frame body 33, the fifth frame 351, the first connection frame 352, the sixth frame 353, the second connection frame 354 and the seventh frame 355 as a whole roughly form an "S" shape.

[0145] The "S"-shaped structure of the frame 33 can also be achieved by bending. During the bending process, the flange 3422 of the elastic membrane 34 is first placed in the recesses of the fifth frame 351 and the sixth frame 353, and then the fifth frame 351 is bent relative to the sixth frame 353, so that the elastic membrane 34 can be installed.

[0146] Optionally, the seventh frame 355 contacts the surface of the sixth frame 353 facing away from the fifth frame 351 , or there is a gap between the seventh frame 355 and the surface of the sixth frame 353 facing away from the fifth frame 351 . All of the above methods are possible and are not specifically limited.

[0147] Optionally, there is a gap between the seventh frame 355 and the surface of the sixth frame 353 facing away from the fifth frame 351, and the size of the gap in the Y direction is 0mm-0.05mm, and can be specifically 0.01mm, 0.015mm, 0.02mm, 0.025mm, 0.03mm, 0.035mm, 0.04mm, 0.045mm, 0.05mm, etc., without specific limitation. In a specific embodiment, the size of the gap in the Y direction is 0.05mm.

[0148] By setting the frame body 33 to include the fifth frame 351, the first connecting frame 352, the sixth frame 353, the second connecting frame 354 and the seventh frame 355 which are connected in sequence, the fifth frame 351, the first connecting frame 352 and the sixth frame 353 jointly enclose the installation groove 331, and the seventh frame 355 is connected to the middle shell 10 and the cover plate 21. It is also possible to realize the connection between the frame body 33, the middle shell 10 and the cover plate 21 while installing the elastic membrane 34, and the structure is simple.

[0149] In one embodiment, reference Figure 5The fifth frame 351, the first connecting frame 352 and the sixth frame 353 are all located in the first space 40, the seventh frame 355 protrudes from the side of the first connecting frame 352 facing away from the second connecting frame 354, and the part of the seventh frame 355 protruding from the first connecting frame 352 is connected to the middle shell 10 and the cover plate 21.

[0150] Optionally, the seventh frame 355 can be connected to the middle shell 10 and the cover plate 21 by welding, screwing, riveting, etc., without limitation. Exemplarily, the seventh frame 355 is fixed to the middle shell 10 and the cover plate 21 by welding, and the seventh frame 355 protrudes from the side of the first connection frame 352 facing away from the second connection frame 354, thereby providing a welding position for facilitating the welding operation.

[0151] By providing the seventh frame 355 protruding from the side of the first connection frame 352 facing away from the second connection frame 354 , it is convenient to connect the frame body 33 with the middle shell 10 and the cover plate 21 .

[0152] In one embodiment, reference Figure 5 The first connection frame 352 includes a first outer surface 3521 facing away from the fifth frame 351 and the sixth frame 353 , and the first outer surface 3521 is an arc surface.

[0153] Optionally, the first outer surface 3521 is smoothly connected to a surface of the fifth frame 351 facing away from the sixth frame 353 and a surface of the sixth frame 353 facing the seventh frame 355 .

[0154] The first outer surface 3521 is an outwardly convex surface. In the cross section of the frame body 33, the contour line of the first outer surface 3521 is an arc line. The first outer surface 3521 is tangent to the surface of the fifth frame 351 facing away from the sixth frame 353. The first outer surface 3521 is also tangent to the surface of the sixth frame 353 facing the seventh frame 355.

[0155] During installation, the frame body 33 is moved relative to the intermediate shell 10 and the cover plate 21. The intermediate shell 10 and the cover plate 21 can first contact with the first outer surface 3521. Since the first outer surface 3521 is an arc surface, the intermediate shell 10 and the cover plate 21 will slide along the first outer surface 3521 and contact with the surface of the installation frame facing the storage space to complete accurate positioning. After that, the seventh frame 355 is connected to the intermediate shell 10 and the cover plate 21, for example, by welding and fixing.

[0156] By setting the first outer surface 3521 as an arc surface, when the middle shell 10 and the cover plate 21 are connected to the seventh frame 355, the first outer surface 3521 can guide the middle shell 10 and the cover plate 21 to ensure accurate positioning.

[0157] In another embodiment, referring to Figure 6The middle shell 10 includes a main shell 15 and a side shell 16 . The side shell 16 is connected to the edge of the main shell 15 , and the side shell 16 is bent relative to the main shell 15 toward the first space 40 .

[0158] The intermediate shell 10 can be an integrated structure, that is, the main shell 15 and the side shell 16 are an integrated structure made by an integrated molding process. For example, a long plate can be used to bend to form the intermediate shell 10, or it can be formed by other processes without limitation. The intermediate shell 10 can also be a split structure, and the main shell 15 and the side shell 16 are connected and fixed by welding, screwing, riveting, etc. The frame protrudes from the side surface of the main shell 15 facing the first space 40.

[0159] The side surface of the side shell 16 facing the first space 40 can be a plane, a curved surface, etc., without limitation. Optionally, the side surface of the side shell 16 facing the first space 40 is a plane, and the surface of the side shell 16 facing the first space 40 and the surface of the main shell 15 facing the first space 40 have an angle, and the angle can be 90°-130°, specifically 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, etc., without limitation.

[0160] The side shell 16 includes a connection surface 161 facing away from the first space 40 . The frame 33 is connected to the connection surface 161 . The frame 33 and the side shell 16 together enclose the installation groove 331 .

[0161] The frame 33 and the connection surface 161 may be connected by welding, clamping, screwing, riveting, etc. The frame 33 and the connection surface 161 are together formed to form a mounting groove 331 and receive at least part of the flange 3422 and the body 3421 .

[0162] By setting the middle shell 10 to include a side shell 16 bent toward the first space 40 relative to the main shell 15, the connecting surface 161 of the side shell 16 facing away from the first space 40 and the frame 33 jointly enclose the installation groove 331, so that the elastic membrane 34 is installed on the frame 33 and the connection between the frame 33 and the middle shell 10 is achieved, and the structure is simple.

[0163] Similarly, the cover plate 21 and the bottom plate 11 may also include a main board and an edge plate, wherein the edge plate is connected to the edge of the main board and is bent relative to the main board toward the first space 40. The surface of the edge plate facing away from the first space 40 is connected to the frame 33 and together encloses the mounting groove 331, which will not be described in detail.

[0164] In one embodiment, reference Figure 6The frame body 33 includes an eighth frame 361 and a ninth frame 362. The eighth frame 361 is connected to the ninth frame 362 and is in an "L" shape. The end of the eighth frame 361 away from the ninth frame 362 is connected to the connecting surface 161. The area of ​​the ninth frame 362 close to the eighth frame 361 is recessed to form a snap-in groove 3311 together with the connecting surface 161. There is a gap between the area of ​​the ninth frame 362 away from the eighth frame 361 and the side shell 16 to form a connecting groove 3312.

[0165] The eighth frame 361 and the ninth frame 362 may both be in the form of a ring connected end to end along the annular direction of the frame body 33, or one or both of them may be a multi-segment structure arranged in sequence along the annular direction, without limitation. The ninth frame 362 protrudes from the surface of the eighth frame 361 facing the mounting groove 331, and in the cross section at any position of the frame body 33, the eighth frame 361 and the ninth frame 362 generally form an "L"-shaped structure, and the two and the connecting surface 161 together enclose the mounting groove 331.

[0166] The eighth frame 361 and the ninth frame 362 may be an integrated structure, for example, a long plate may be bent to form the frame body 33, or may be formed by other processes without limitation. The eighth frame 361 and the ninth frame 362 may also be connected and fixed by welding, screwing, riveting, etc. without limitation.

[0167] In the Y direction, the distance from the bottom wall of the snap-fit ​​groove 3311 to the connecting surface 161 is greater than the distance between the two side walls of the connecting groove 3312 in the Y direction. With this arrangement, after the flange 3422 is placed in the snap-fit ​​groove 3311, the elastic membrane 34 pulls the flange 3422 when deforming, and the flange 3422 snaps with the side wall of the connecting groove 3312 facing the opening of the snap-fit ​​groove 3311 and does not exit through the connecting groove 3312, thereby achieving snap-fit ​​connection between the elastic membrane 34 and the frame 33.

[0168] The end of the eighth frame 361 away from the ninth frame 362 can be connected to the connection surface 161 by welding, bonding, clamping, screwing, riveting, etc., so as to realize the connection between the frame body 33 and the intermediate shell 10. When assembling with the elastic membrane 34, the flange 3422 can be placed in the clamping groove 3311 formed by the ninth frame 362 and the connection surface 161, and then the eighth frame 361 and the connection surface 161 are connected.

[0169] Optional, such as Figure 6As shown, the portion of the ninth frame 362 corresponding to the snap-fitting groove 3311 protrudes in a direction away from the eighth frame 361. When the portion of the ninth frame 362 corresponding to the snap-fitting groove 3311 protrudes in a direction away from the eighth frame 361, the thickness of the portion of the ninth frame 362 corresponding to the snap-fitting groove 3311 (i.e., the size of the portion in the Y direction) and the thickness of the portion of the ninth frame 362 corresponding to the connecting groove 3312 (i.e., the size of the portion in the Y direction) may be substantially the same. In this way, the overall thickness of the ninth frame 362 is substantially the same, and the structural strength is good.

[0170] In other embodiments, the portion of the ninth frame 362 corresponding to the engaging groove 3311 does not protrude in the direction away from the eighth frame 361. In other words, the ninth frame 362 is substantially a flat plate, and the surface of the ninth frame 362 facing the eighth frame 361 is recessed in the area of ​​the ninth frame 362 close to the eighth frame 361 to form the engaging groove 3311.

[0171] By setting the frame body 33 to include the eighth frame 361 and the ninth frame 362, the installation groove 331 is formed between the eighth frame 361, the ninth frame 362 and the connecting surface 161, and the simple structure can realize the installation with the elastic membrane 34 and provide a stable supporting foundation for the elastic membrane 34, and the structure is simple.

[0172] In one embodiment, reference Figure 6 The end surface of the side shell 16 away from the main shell 15 is smoothly connected to the connecting surface 161, and there is a gap between the smoothly connected area and the ninth shell to form a connecting groove 3312.

[0173] Optionally, the smoothly connected area is tangent to both the end surface of the side shell 16 away from the main shell 15 and the connecting surface 161. The smoothly connected area protrudes toward the ninth shell, and there is a gap between the smoothly connected area and the ninth shell to form a connecting groove 3312 to accommodate at least part of the body 3421.

[0174] After installation, the main body 3421 of the elastic membrane 34 will contact the end face of the side shell 16 away from the main shell 15. By arranging a smooth connection between the end face of the side shell 16 away from the main shell 15 and the connecting surface 161, it is avoided that the end of the side shell 16 away from the main shell 15 crushes the main body 3421 of the elastic membrane 34, and the service life of the elastic membrane 34 can be improved.

[0175] In one embodiment, the frame 33 has rounded corners at positions where the main body portion 341 and the edge portion 342 meet.

[0176] In a specific embodiment, Figure 3 As shown, the end of the second plate 3322 away from the first plate 3321 is rounded. In another specific embodiment, as Figure 4As shown, one end of the fourth frame 335 away from the middle shell 10 or the cover plate 21 is smoothly connected to a surface of the fourth frame 335 facing the third frame 334. In another specific embodiment, as Figure 5 As shown, the second connection frame 354 includes a second outer surface 3541 facing away from the sixth frame 353 and the seventh frame 355, and the second outer surface 3541 is an arc surface. Figure 6 As shown, one end of the ninth frame 362 away from the eighth frame 361 is smoothly connected to the surface of the ninth frame 362 facing the side shell 16 .

[0177] By providing the frame 33 with a rounded corner at the position where the main body 341 and the edge portion 342 meet, it is avoided that the sharp corner structure at the meeting point is in contact with the elastic membrane 34 to produce a shearing effect, thereby increasing the service life of the elastic membrane 34.

[0178] In one embodiment, reference Figure 2 The inner wall surface of the intermediate shell 10 is provided with a plurality of protrusions 14 arranged at intervals.

[0179] The shape and size of the protrusions 14 are not limited, and may be block-shaped, column-shaped, etc. The multiple protrusions 14 may be arranged at equal intervals, or the interval between two adjacent protrusions 14 is not limited. In one embodiment, the multiple protrusions 14 are arranged in an array.

[0180] The plurality of protrusions 14 may be provided on any one or a combination of the bottom plate 11, the first side plate 12 and the second side plate 13. For example, in one embodiment, Figure 2 As shown, the bottom plate 11, the first side plate 12 and the second side plate 13 are all provided with a plurality of protrusions 14. Alternatively, the first side plate 12 and the second side plate 13 are provided with a plurality of protrusions 14, and the bottom plate 11 is not provided with protrusions 14. Alternatively, the plurality of protrusions 14 are all provided on the bottom plate 11. All of the above methods are possible and are not specifically limited.

[0181] The protrusion 14 and the intermediate shell 10 may be an integral structure, or the protrusion 14 may be connected and fixed to the inner wall surface of the intermediate shell 10 by welding, screwing, riveting or other processes, without specific limitation.

[0182] By providing the inner wall surface of the intermediate shell 10 with a plurality of protrusions 14 arranged at intervals, the battery cell 50 in the storage space can be positioned and limited to prevent the battery cell 50 from moving around in the X direction and the Z direction, thereby ensuring that the relative position of the battery cell 50 and the elastic membrane 34 is accurate, thereby making the elastic membrane 34 elastically abut against the large surface of the battery cell 50.

[0183] In one embodiment, the end cover assembly 20 further includes a one-way valve (not shown), which is disposed on the cover plate 21 and is used to release pressure when the internal pressure of the energy storage device 100 reaches a threshold value.

[0184] Optionally, the cover plate 21 is provided with a vent hole (not shown), and the one-way valve is arranged at the vent hole. The one-way valve and the cover plate 21 can be connected by welding, bonding, clamping, screwing, etc., without specific limitation. The specific structure of the one-way valve can refer to any feasible solution, and the embodiment of the present application does not limit it.

[0185] The one-way valve only allows the excess gas inside the energy storage device 100 to be discharged, but does not allow external gas to enter the energy storage device 100. In this way, the pressure can be released in time when the pressure inside the energy storage device 100 is too high, thereby ensuring the safety of the energy storage device 100.

[0186] The embodiment of the present application further provides an energy storage device, including the energy storage device 100 in the embodiment of the present application and a reinforcing plate, wherein the reinforcing plate is arranged on at least one side of the energy storage device 100 in the thickness direction.

[0187] Optionally, the energy storage device further includes a box having a receiving space, and the energy storage device 100 is received in the receiving space.

[0188] The box body is made of a material with high structural strength, specifically metal materials, high-strength plastics, ceramics, etc. Metal materials include aluminum, aluminum alloys, magnesium alloys, iron and iron alloys, etc. The box body can be an integrated structure, that is, the box body is an integrated structure made by an integrated molding process, and the integrated molding process can be stamping, casting, etc., without limitation. The box body can also be a split structure, and the various parts can be connected and fixed by welding, bonding, clamping, screwing, etc.

[0189] In one embodiment, the box body of the energy storage device is roughly a rectangular parallelepiped. The box body includes a bottom wall and four connecting plates, which are connected to the bottom wall and enclosed to form a receiving space. The four connecting plates include a first connecting plate and a second connecting plate that are opposite in the Y direction. The reinforcing plate is received in the receiving space and is arranged between the energy storage device 100 and the first connecting plate, and / or the reinforcing plate is arranged between the energy storage device 100 and the second connecting plate, without specific limitation.

[0190] The energy storage device in the embodiment of the present application, by arranging a reinforcing plate on at least one side in the Y direction, can provide additional pre-tightening force to the battery cell 50 in the thickness direction (i.e., the Y direction) of the battery cell 50 in addition to the pre-tightening force provided by the elastic membrane 34, thereby meeting the working requirements of the energy storage device 100.

[0191] In one embodiment, there are multiple energy storage devices 100, and the multiple energy storage devices 100 are arranged in sequence along the Y direction; a reinforcing plate is provided on the outermost side of the multiple energy storage devices 100 in the Y direction, and / or a reinforcing plate is provided between two adjacent energy storage devices 100.

[0192] Optionally, the reinforcing plate is disposed between the energy storage device 100 closest to the first connecting plate among the multiple energy storage devices 100 in the Y direction and the first connecting plate, and / or, the reinforcing plate is disposed between the energy storage device 100 closest to the second connecting plate among the multiple energy storage devices 100 in the Y direction and the second connecting plate. The reinforcing plate may also be disposed between any two adjacent energy storage devices 100, and a reinforcing plate may be disposed between two adjacent energy storage devices 100, or, among the multiple energy storage devices 100 disposed sequentially along the Y direction, a reinforcing plate may be disposed between every two energy storage devices 100, and the reinforcing plate may also be disposed in other ways, which are not specifically limited.

[0193] Exemplarily, reinforcing plates are provided between the energy storage device 100 closest to the first connecting plate among the multiple energy storage devices 100 and the first connecting plate, between the energy storage device 100 closest to the second connecting plate among the multiple energy storage devices 100 and the second connecting plate, and between two adjacent energy storage devices 100.

[0194] Optionally, the reinforcing plate may be connected and fixed to the box body / energy storage device 100, or the reinforcing plate may be movable in the Y direction, without specific limitation.

[0195] At least one reinforcing plate is movable in the Y direction. Optionally, there is one reinforcing plate, which is arranged at the outermost side of the energy storage device in the Y direction, and the reinforcing plate can be moved in the Y direction to clamp the energy storage device to prevent the energy storage device from over-expanding; or, there are two reinforcing plates, which are respectively arranged on both sides of the outermost side of the energy storage device in the Y direction, one of which is connected and fixed to the box body, and the other reinforcing plate can move relative to the reinforcing plate; or, there are multiple reinforcing plates, and reinforcing plates are arranged between the energy storage device 100 closest to the second connecting plate and the second connecting plate among the multiple energy storage devices 100, and between two adjacent energy storage devices 100, one of which is arranged at the outermost reinforcing plate of the energy storage device in the Y direction and is connected and fixed to the box body, and the remaining reinforcing plates can move relative to the reinforcing plate. The above method and any other feasible method are all possible, and there is no specific limitation.

[0196] In this configuration, by providing a movable reinforcing plate, the reinforcing plate can be moved toward or away from the energy storage device 100, which can further increase the squeezing force on the battery cell and prevent the battery cell from excessive expansion and degradation.

[0197] By arranging a reinforcing plate at the outermost sides of the plurality of energy storage devices 100 in the overall thickness direction, and / or arranging a reinforcing plate between two adjacent energy storage devices 100, in addition to the preload force provided by the elastic membrane 34, the reinforcing plate can provide additional preload force to the battery cell 50 to meet the working requirements of the energy storage device 100.

[0198] The embodiment of the present application further provides a power system, including an electrical device and the energy storage device 100 in the embodiment of the present application, or an energy storage device such as the embodiment of the present application, the energy storage device 100 or the energy storage device supplies power to the electrical device.

[0199] The power system can be an electric vehicle, a hybrid vehicle, a base station, a household power load, etc., without specific limitation.

[0200] The power system in the embodiment of the present application adopts the energy storage device 100 or energy storage equipment in the embodiment of the present application. The energy storage device 100 or energy storage equipment can provide sufficient preload force to the battery cell 50 to meet the working requirements of the energy storage device 100 or the energy storage equipment.

[0201] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0202] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiment and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. An energy storage device (100), characterized in that: include: The intermediate shell (10) comprises a bottom plate (11), a first side plate (12) and a second side plate (13), wherein the first side plate (12) and the second side plate (13) are connected to the bottom plate (11), and the first side plate (12) and the second side plate (13) are both located on the same side of the bottom plate (11), and the first side plate (12) and the second side plate (13) are arranged relatively spaced apart. An end cover assembly (20), comprising a cover plate (21), wherein the cover plate (21) is connected to the first side plate (12) and the second side plate (13) and is opposite to the bottom plate (11), and the intermediate shell (10) and the cover plate (21) enclose a first space (40); The first side shell (31) and the second side shell (32) are connected to the bottom plate (11), the first side plate (12), the second side plate (13) and the cover plate (21), and the first side shell (31) and the second side shell (32) are arranged relatively spaced apart; At least one of the first side shell (31) and the second side shell (32) comprises a frame (33) and an elastic membrane (34); the frame (33) is in a ring shape connected end to end, and the frame (33) is connected to the bottom plate (11), the first side plate (12), the second side plate (13) and the cover plate (21); the elastic membrane (34) comprises a main body (341) and an edge portion (342); the edge portion (342) is connected to the four sides of the main body (341). The frame (33) has a mounting groove (331), the opening of the mounting groove (331) faces the first space (40), the edge portion (342) extends into the mounting groove (331) and is connected to the frame (33), the main body (341) protrudes relative to the frame (33) in a direction away from the intermediate shell (10); the main body (341) encloses a second space (3411), and the second space (3411) is in communication with the first space (40), A battery cell (50) is accommodated in the first space (40) and the second space (3411); in a cross section along the height direction of the energy storage device (100), the battery cell (50) is a runway-type wound battery cell, or a rectangular stacked battery cell; the relative direction between the first side shell (31) and the second side shell (32) is the thickness direction of the battery cell (50); and the elastic membrane (34) is in elastic contact with a large surface of the battery cell (50).

2. The energy storage device (100) according to claim 1, characterized in that: The minimum distance between the first side shell (31) and the second side shell (32) is smaller than the thickness of the battery cell (50).

3. The energy storage device (100) according to claim 2, characterized in that: The mounting groove (331) comprises a snap-fit ​​groove (3311) and a connecting groove (3312); the opening of the connecting groove (3312) is connected to the junction of the first space (40) and the second space (3411); the other end of the connecting groove (3312) is connected to the snap-fit ​​groove (3311); and the spacing dimension between two opposite inner wall surfaces of the snap-fit ​​groove (3311) is greater than the spacing dimension between two opposite inner wall surfaces of the connecting groove (3312); The edge portion (342) includes a body (3421) and a flange (3422); the body (3421) is annular and the inner four edges are connected to the main body (341); the flange (3422) is connected to the outer four edges of the body (3421); the thickness of the flange (3422) is greater than the thickness of the body (3421); the flange (3422) is accommodated in the snap-fit ​​groove (3311), and at least a portion of the body (3421) is accommodated in the connecting groove (3312).

4. The energy storage device (100) according to claim 3, characterized in that: The direction of the snap-in groove (3311) toward the connecting groove (3312) forms an angle with the opening direction of the connecting groove (3312); in the cross section of the elastic membrane (34), the main body (3421) is bent, and an angle is formed between the main body (3421) and the main body (341).

5. The energy storage device (100) according to claim 4, characterized in that: The frame (33) comprises a first frame (332) and a second frame (333), the first frame (332) comprises a first plate (3321) and a second plate (3322), the first plate (3321) and the second plate (3322) are connected and are in an "L" shape in a cross section of the frame (33), the second frame (333) is arranged on a surface of the first plate (3321) facing the battery cell (50), and on a side of the second plate (3322) facing the first plate (3321), The second frame (333) is connected to one end of the first plate (3321) away from the second plate (3322), the second frame (333) and the first plate (3321) enclose the snap-in groove (3311), the gap between the second frame (333) and the first plate (3321) and the second plate (3322) forms the connecting groove (3312), and there is a gap between the second frame (333) and the second plate (3322) to form the opening of the connecting groove (3312).

6. The energy storage device (100) according to claim 5, characterized in that: The second frame (333) includes a third plate (3331), a fourth plate (3332) and a fifth plate (3333) which are connected in sequence, the third plate (3331) is connected to the first plate (3321), the fourth plate (3332) is recessed in a direction away from the first plate (3321), the fifth plate (3333) and the second plate (3322) are spaced apart, the fourth plate (3332) and the first plate (3321) jointly enclose the snap-in groove (3311), and the fifth plate (3333) and the first plate (3321) and the second plate (3322) jointly enclose the connecting groove (3312).

7. The energy storage device (100) according to claim 5, characterized in that: The second frame (333) protrudes from one end of the first plate (3321) away from the second plate (3322), and the portion of the second frame (333) protruding from the first plate (3321) is connected to the intermediate shell (10) and the cover plate (21).

8. The energy storage device (100) according to claim 3, characterized in that: The frame body (33) includes a third frame (334) and a fourth frame (335), the third frame (334) is closer to the intermediate shell (10) than the fourth frame (335), the third frame (334) is connected to the intermediate shell (10) and the cover plate (21), the third frame (334) and the fourth frame (335) are connected and jointly enclose the mounting groove (331), and the direction of the snap-in groove (3311) toward the connecting groove (3312) is on the same straight line as the opening direction of the connecting groove (3312).

9. The energy storage device (100) according to claim 8, characterized in that: An opening end of the third frame (334) away from the connecting groove (3312) protrudes from the fourth frame (335).

10. The energy storage device (100) according to claim 8, characterized in that: A step is provided at the junction of the end surface of the third frame (334) away from the opening of the connecting groove (3312) and the surface of the third frame (334) away from the fourth frame (335), and the intermediate shell (10) and the cover plate (21) are connected to the step.

11. The energy storage device (100) according to claim 3, characterized in that: In a cross section of the frame body (33), the frame body (33) is in an "S" shape and comprises a fifth frame (351), a first connecting frame (352), a sixth frame (353), a second connecting frame (354) and a seventh frame (355) which are connected in sequence, the fifth frame (351) is opposite to the sixth frame (353), the first connecting frame (352) connects the fifth frame (351) and the sixth frame (353), and the fifth frame (351), the first connecting frame (352) and the sixth frame (353) jointly enclose the installation groove (331) , and the direction of the snap-in groove (3311) toward the connecting groove (3312) is on the same straight line as the opening direction of the connecting groove (3312), the second connecting frame (354) is connected to the end of the sixth frame (353) away from the first connecting frame (352), the seventh frame (355) is arranged on the side of the sixth frame (353) facing away from the fifth frame (351), the seventh frame (355) is connected to the second connecting frame (354), and the seventh frame (355) is connected to the intermediate shell (10) and the cover plate (21).

12. The energy storage device (100) according to claim 11, characterized in that: The fifth frame (351), the first connecting frame (352) and the sixth frame (353) are all located in the first space (40); the seventh frame (355) protrudes from the side of the first connecting frame (352) facing away from the second connecting frame (354); and the portion of the seventh frame (355) protruding from the first connecting frame (352) is connected to the intermediate shell (10) and the cover plate (21).

13. The energy storage device (100) according to claim 12, characterized in that: The first connecting frame (352) comprises a first outer surface (3521) facing away from the fifth frame (351) and the sixth frame (353), and the first outer surface (3521) is an arc surface.

14. The energy storage device (100) according to claim 3, characterized in that: The intermediate shell (10) comprises a main shell (15) and a side shell (16); the side shell (16) is connected to the edge of the main shell (15); the side shell (16) is bent relative to the main shell (15) toward the first space (40); the side shell (16) comprises a connecting surface (161) facing away from the first space (40); the frame (33) is connected to the connecting surface (161), and the frame (33) and the side shell (16) jointly enclose the installation groove (331).

15. The energy storage device (100) according to claim 14, characterized in that: The frame body (33) includes an eighth frame (361) and a ninth frame (362), the eighth frame (361) is connected to the ninth frame (362) and is in an "L" shape, the end of the eighth frame (361) away from the ninth frame (362) is connected to the connecting surface (161), the area of ​​the ninth frame (362) close to the eighth frame (361) is recessed to form the snap-in groove (3311) together with the connecting surface (161), and there is a gap between the area of ​​the ninth frame (362) away from the eighth frame (361) and the side shell (16) to form the connecting groove (3312).

16. The energy storage device (100) according to claim 15, characterized in that: The end surface of the side shell (16) away from the main shell (15) is smoothly connected to the connecting surface (161), and a gap is provided between the smoothly connected area and the ninth shell to form the connecting groove (3312).

17. The energy storage device (100) according to any one of claims 1 to 16, characterized in that: The frame (33) has rounded corners at positions where the main body (341) and the edge (342) meet.

18. The energy storage device (100) according to any one of claims 1 to 16, characterized in that: The inner wall surface of the intermediate shell (10) is provided with a plurality of protrusions (14) arranged at intervals.

19. The energy storage device (100) according to any one of claims 1 to 16, characterized in that: The end cover assembly (20) further comprises a one-way valve, which is arranged on the cover plate (21) and is used to release pressure when the internal pressure of the energy storage device (100) reaches a threshold value.

20. An energy storage device, characterized in that: include: The energy storage device (100) according to any one of claims 1 to 19; A reinforcing plate is arranged on at least one side of the energy storage device (100) in the thickness direction.

21. The energy storage device according to claim 20, characterized in that: There are a plurality of energy storage devices (100), and the plurality of energy storage devices (100) are arranged in sequence along the thickness direction; the plurality of energy storage devices (100) as a whole are provided with the reinforcing plate at the outermost sides in the thickness direction of the energy storage device (100), and / or the reinforcing plate is provided between two adjacent energy storage devices (100); At least one of the reinforcing plates is movable in the thickness direction of the energy storage device (100).

22. A power system, characterized in that: include: Electrical equipment; The energy storage device (100) according to any one of claims 1 to 19, wherein the energy storage device (100) supplies power to the electrical device; or The energy storage device as claimed in claim 20 or 21, wherein the energy storage device supplies power to the electrical device.

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