Energy storage devices and electrical equipment

Abstract

The present application discloses an energy storage device and an electrical equipment, the energy storage device comprises: a shell, comprising an opening; a battery cell, comprising a battery cell body and a pole ear, the battery cell body comprising a side and a top surface connected to the side, the pole ear is led out from the side and connected to the battery cell body; and an end cap assembly, comprising a lower plastic and a pole column, the lower plastic comprises a body and a limiting protrusion, the body comprises a top surface and a bottom surface arranged opposite to each other, the lower plastic further comprises a mounting groove, the mounting groove is recessed in the bottom surface and located at the end of the length direction of the lower plastic, the limiting protrusion and the mounting groove are arranged adjacent to each other along the length direction of the lower plastic, the end cap assembly further comprises a pin, the pin comprises a connecting portion and a transition portion connected at an angle, the connecting portion is accommodated in the mounting groove, and the transition portion extends away from the bottom surface. The battery cell is installed in the shell, the end cap assembly is sealed in the opening, the limiting protrusion is abutted against the top surface, the transition portion is stacked on the side and connected to the pole ear, the pole column passes through the body and the connecting portion, and is connected to the connecting portion, and the connecting portion is spaced apart from the top surface.

Description

Technical Field

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

[0002] With the continuous advancement of energy storage technology, the requirements for the internal structure of energy storage devices are getting higher and higher. Existing battery cells usually adopt stacking or winding. When the battery cell adopts stacking, the positive and negative pole tabs of the battery cell are generally led out from the same side or opposite sides of the stacked battery cell, and the positive and negative pole pins in the end cap assembly need to be welded to the positive and negative pole tabs respectively. However, the lower plastic structure in the existing end cap assembly is not convenient for installation with the positive and negative pins. Summary of the invention

[0003] The present application provides an energy storage device and an electrical equipment, which can facilitate the installation of plastic and pins when the battery cell adopts a stacked type and the battery cell's tabs are led out from the side of the battery cell.

[0004] The present application provides an energy storage device, which includes a shell, a battery cell and an end cap assembly, wherein the shell includes an opening. The battery cell includes a battery cell body and a pole ear, wherein the battery cell body includes a side surface and a top surface connected to the side surface, and the pole ear is led out from the side surface and connected to the battery cell body. The end cap assembly includes a lower plastic and a pole, wherein the lower plastic includes a body and a limiting protrusion, wherein the body includes a top surface and a bottom surface, wherein the top surface and the bottom surface are arranged opposite to each other along the thickness direction of the body, wherein the lower plastic also includes a mounting groove, wherein the mounting groove is recessed in the bottom surface and located at the end of the length direction of the lower plastic, wherein the limiting protrusion is arranged adjacent to the mounting groove along the length direction of the lower plastic, and wherein the end cap assembly also includes a pin, wherein the pin includes a connecting portion and a transition portion, wherein the transition portion is connected to the connecting portion at an angle, wherein the connecting portion is accommodated in the mounting groove, and wherein the transition portion extends away from the bottom surface. The battery cell is installed in the shell, the end cover assembly is encapsulated in the opening, the limiting protrusion is in contact with the top surface of the battery cell facing the opening, the transition portion is stacked on the side and connected to the pole ear, the pole passes through the body and the connecting portion, and the pole is conductively connected to the connecting portion, wherein the connecting portion is spaced apart from the top surface of the battery cell.

[0005] It is understandable that in the related art, the battery cell is usually laminated or wound. When the battery cell is laminated, the positive and negative pole tabs of the battery cell are generally led out from the same side or opposite sides of the laminated battery cell, and the positive and negative pole pins in the end cap assembly need to be welded to the positive and negative pole tabs, respectively. However, the lower plastic structure in the existing end cap assembly is not convenient for installation with the positive and negative pole pins.

[0006] In the embodiment of the present application, when the battery cell adopts a stacked structure, the pole ear is led out from the side of the battery cell body, and the pole ear includes a connecting portion and a transition portion connected at an angle. The connecting portion is located in the mounting groove formed by the lower plastic recess, so that the pin is fixed in a limited position on the lower plastic. The pole is penetrated by the lower plastic and the connecting portion, and is electrically conductive with the connecting portion, and the transition portion is stacked and connected with the pole ear to achieve the conduction of current between the battery cell body and the pole. The limiting protrusion of the lower plastic is arranged adjacent to the mounting groove, and is used to abut against the top surface of the battery cell, preventing the multiple positive and negative electrode sheets constituting the battery cell from being misaligned or offset, not only having a fixed limiting effect on the battery cell as a whole, but also separating the connecting portion of the pin from the battery cell body to prevent the battery cell and the pin from short-circuiting, facilitating the assembly of the pin and the lower plastic in the end cover assembly, and ensuring the safety of the energy storage device.

[0007] In one embodiment, the lower plastic further includes two convex ribs, both of which are convexly disposed on the bottom surface, and the two convex ribs are respectively located at opposite edges of the bottom surface in the width direction. The energy storage device further includes a protective film, which is located between the shell and the battery cell and wraps the bottom and peripheral side of the battery cell, and the protective film has an assembly opening, the top surface is located at the assembly opening, and the assembly opening faces the bottom surface. The two end surfaces of the limiting protrusion along the width direction of the lower plastic have channels between them and the two convex ribs.

[0008] It can be understood that the assembly opening of the protective film faces the lower plastic, the two convex ribs of the lower plastic extend toward the assembly opening of the protective film, and the protective film at the edge of the assembly opening and the two convex ribs of the lower plastic are connected and fixed by a hot melt process to ensure that the protective film insulates the battery cell and the shell. The channels formed by the two convex ribs and the two end faces in the width direction of the limiting protrusion are used for the gas inside the energy storage device to pass through, ensuring that in the event of thermal runaway of the energy storage device, the internal gas can pass through the channel in time and be discharged from the energy storage device, thereby accelerating the gas circulation rate inside the energy storage device, avoiding the accumulation of gas inside the energy storage device and the inability to be discharged in time, and improving the safety and reliability of the energy storage device.

[0009] In one embodiment, the height of the limiting protrusion protruding from the bottom surface is greater than or equal to 2 mm and less than or equal to 4 mm.

[0010] It can be understood that the dimension of the limiting protrusion that sinks toward the battery cell relative to the body is greater than or equal to 2 mm and less than or equal to 4 mm, so that the surface of the limiting protrusion facing away from the body abuts against the top surface of the battery cell.

[0011] In one embodiment, the mounting groove includes a groove bottom wall and a groove side wall connected to the groove bottom wall. Along the length direction of the lower plastic, there is a gap between the surface of the groove side wall facing away from the mounting groove and connected to the limiting protrusion and the surface of the adapter portion facing away from the connecting portion.

[0012] It can be understood that the connecting portion of the pin is accommodated in the mounting groove, and the adapter portion of the pin extends out of the mounting groove and is arranged relative to the groove side wall of the mounting groove, and a gap is formed. Specifically, the mounting groove and the limiting protrusion are arranged adjacent to each other along the length direction of the lower plastic, and the groove side wall of the mounting groove has at least a portion opposite to and connected to the limiting protrusion, and there is a gap between the surface of the groove side wall of the mounting groove facing away from the connecting portion of the mounting groove and the limiting protrusion and the surface of the adapter portion facing away from the connecting portion. The gap is used to reserve enough space for the pin and the tab for welding, and to accommodate the pre-welding of tabs and adapter portions of different thicknesses.

[0013] In one embodiment, the width of the gap is greater than or equal to 0.2 mm and less than or equal to 3 mm.

[0014] It can be understood that in some embodiments, the gap width formed between the surface of the transition portion facing away from the connecting portion and the portion of the groove side wall of the mounting groove opposite to the limiting protrusion is set to be greater than or equal to 0.2 mm and less than or equal to 3 mm to ensure good welding of the tab and the pin.

[0015] In one embodiment, the lower plastic also includes an extension section, the extension section is convexly arranged on the end surface of the groove side wall facing away from the groove bottom wall, the extension section and the limiting protrusion are spaced and opposite to each other along the length direction of the body, and the extension section is located at the end of the length direction of the body. The protective film on the periphery of the assembly port is connected to the extension section by a hot melt process.

[0016] It can be understood that the extension section is arranged on the side of the installation groove away from the limiting protrusion. Specifically, the extension section is convexly arranged on a part of the groove side wall of the installation groove opposite to the limiting protrusion, and is convexly arranged on the end surface of the groove side wall facing away from the groove bottom wall. The extension section is used to connect with the two convex ribs and the edge of the assembly opening of the protective film through a hot melt process to achieve the fixation of the protective film on the lower plastic, ensure the insulation of the protective film to the battery cell, and ensure the safety of the energy storage device.

[0017] In one embodiment, the lower plastic further comprises two positioning posts, both of which are convexly disposed on the bottom wall of the groove, and the two positioning posts are staggered along the length direction and width direction of the lower plastic. The connecting portion comprises two limiting holes, both of which penetrate through the two surfaces of the connecting portion in the thickness direction, and each of the positioning posts is disposed through one of the limiting holes.

[0018] It can be understood that the two positioning posts included in the lower plastic are located in the installation groove, the connecting part of the pin is accommodated in the installation groove, and the positioning posts are passed through the limiting holes of the connecting part to facilitate the assembly and positioning of the pin and the lower plastic.

[0019] In one embodiment, the end cap assembly further includes an end cap, and the end cap and the lower plastic are stacked along the thickness direction of the end cap assembly, and the end cap is located on the side of the lower plastic facing away from the battery cell. The lower plastic further includes a boss, and the bosses are all convexly arranged on the bottom surface, and the mounting groove is concavely arranged on the boss. Along the width direction of the lower plastic, the boss and the two convex ribs are spaced and form a flow channel, and the flow channel is connected to the channel. The lower plastic further includes an explosion-proof fence, and the explosion-proof fence has a plurality of air holes, and the plurality of air holes penetrate the two sides of the lower plastic in the thickness direction, and the plurality of air holes are connected to the flow channel.

[0020] It can be understood that the flow channel formed between the boss and the two convex ribs and the channel formed between the limiting protrusion and the two convex ribs are connected, and the channel is connected to the air vents in the explosion-proof fence on the lower plastic, and the flow channel is connected to the air vents. The gas inside the energy storage device can enter the flow channel, the channel and the air vents in the explosion-proof fence from the bottom and side of the battery cell in turn, and be discharged from the energy storage device through the explosion-proof hole of the end cover, ensuring that the internal gas can be discharged from the energy storage device in time in the event of thermal runaway, thereby accelerating the gas circulation rate inside the energy storage device, avoiding the accumulation of gas inside the energy storage device and being unable to be discharged in time, and improving the safety and reliability of the energy storage device.

[0021] In one embodiment, the side surface includes a first side surface and a second side surface, the first side surface and the second side surface are arranged opposite to each other along the width direction of the battery body, the tab includes a first tab and a second tab, the first tab is led out from the first side surface, and the second tab is led out from the second side surface. The pin includes a first pin and a second pin, the first pin includes a first connecting portion and a first transition portion, the first transition portion includes a first outer side surface, the second pin includes a second connecting portion and a second transition portion, the second transition portion includes a second outer side surface, the first outer side surface and the second outer side surface are both facing away from the battery body, the first outer side surface is connected to the first tab, and the second outer side surface is connected to the second tab. The mounting groove includes a first mounting groove and a second mounting groove, the first connecting portion is accommodated in the first mounting groove, the first mounting groove includes a first groove side wall, a first gap is formed between the first outer side surface and the first groove side wall, the second mounting groove includes a second groove side wall, and a second gap is formed between the second outer side surface and the second groove side wall. The width of the first gap is greater than or equal to 0.8 mm and less than or equal to 3 mm, and the width of the second gap is greater than or equal to 0.2 mm and less than or equal to 2.5 mm.

[0022] It can be understood that the first pole lug and the second pole lug are led out from opposite sides in the width direction of the battery cell, the first pole lug is connected to the first adapter portion of the first pin, and the second pole lug is connected to the second adapter portion of the second pin. The first adapter portion has a first outer side surface facing away from the battery cell, the first groove side wall of the first installation groove is opposite to the limiting protrusion, and the gap between the first outer side surface and the first groove side wall of the first installation groove is the first gap, and the second adapter portion has a second outer side surface facing away from the battery cell, the second groove side wall of the second installation groove is opposite to the limiting protrusion, and the gap between the second outer side surface and the second groove side wall of the second installation groove is the second gap. In order to take into account the different sizes of the first pin and the second pin, the widths of the first gap and the second gap are different.

[0023] In one embodiment, the first mounting groove further includes a first groove bottom wall, and the second mounting groove further includes a second groove bottom wall. The lower plastic further includes two first positioning columns and two second positioning columns, the two first positioning columns are both protruding from the first groove bottom wall, and are staggered along the length direction and width direction of the lower plastic, and the two second positioning columns are both protruding from the second groove bottom wall, and are symmetrically arranged along the length direction and width direction of the lower plastic. The first connecting portion includes two first limiting holes, the two first limiting holes both penetrate the two surfaces of the first connecting portion in the thickness direction, and each of the first positioning columns is penetrated in one of the first limiting holes, and the second connecting portion includes two second limiting holes, the two second limiting holes both penetrate the two surfaces of the second connecting portion in the thickness direction, and each of the second positioning columns is penetrated in one of the second limiting holes.

[0024] It can be understood that the first positioning column is located in the first mounting groove, and the first connecting portion of the first pin is accommodated in the first mounting groove. The first pin has a first limiting hole, and the first positioning column is penetrated in the first limiting hole to limit and fix the first pin to the lower plastic. The second positioning column is located in the second mounting groove, and the second connecting portion of the second pin is accommodated in the second mounting groove. The second pin has a second limiting hole, and the second positioning column is penetrated in the second limiting hole to limit and fix the second pin to the lower plastic. Therefore, the first positioning column and the second positioning column respectively provide positioning references for the assembly of the first pin and the second pin in the lower plastic. Since the materials of the first pin and the second pin are different, in order to prevent the first pin and the second pin from being reversed, the two first positioning columns are staggered along the central axis of the length direction and the width direction of the lower plastic, and the second two second positioning columns are symmetrically arranged along the central axis of the length direction and the width direction of the lower plastic, so that when the first pin and the second pin are assembled with the lower plastic, the first pin will not be mistakenly installed in the second mounting groove, and the second pin will not be mistakenly installed in the first mounting groove, thereby playing a foolproof role in the assembly process of the first pin and the second pin.

[0025] The present application provides an electrical device, which includes the energy storage device, and the energy storage device supplies power to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is an application scenario diagram of the energy storage device provided in the embodiment of the present application;

[0027] Figure 2 is a schematic diagram of the structure of the energy storage device provided in an embodiment of the present application;

[0028] Figure 3 for Figure 2 A schematic diagram of the exploded structure of the energy storage device shown;

[0029] Figure 4 for Figure 2 A schematic diagram of a partial structure of the energy storage device shown;

[0030] Figure 5 for Figure 3 A schematic diagram of the structure of the first lower plastic of the end cover assembly in the energy storage device shown;

[0031] Figure 6 for Figure 5 The schematic diagram of the structure of the first lower plastic at another angle is shown;

[0032] Figure 7 for Figure 3 A schematic diagram of the structure of the second lower plastic of the end cover assembly in the energy storage device shown;

[0033] Figure 8 for Figure 7 The schematic diagram of the structure of the second lower plastic shown in another angle;

[0034] Fig. 9 for Figure 3 A schematic diagram of the structure of the end cover of the end cover assembly in the energy storage device shown at another angle;

[0035] Fig.10 for Figure 3 A schematic structural diagram of the first pin and the second pin of the end cover assembly in the energy storage device;

[0036] Fig.11 for Figure 3 A schematic diagram of a partial structure of the energy storage device shown;

[0037] Fig.12 for Figure 2 A partial cross-sectional structural schematic diagram of the energy storage device shown;

[0038] Fig.13 for Fig.12 An enlarged view of the energy storage device at Q is shown;

[0039] Fig.14 for Fig.12 An enlarged view of location W of the energy storage device shown.

[0040] The nouns corresponding to the reference numerals in the figure are: energy storage device 1000, housing 200, opening 201, accommodating cavity 202, end cover assembly 100, end cover 30, upper surface 31, lower surface 32, first through hole 33, second through hole 34, assembly groove 35, explosion-proof hole 36, first limiting groove 37, second limiting groove 38, first pole 40, second pole 50, first pin 60, first connecting portion 61, first through hole 611, first limiting hole 612, first adapter portion 62, first outer side surface 621, first inner side surface 622, second pin 70 , second connecting portion 71, second through hole 711, second limiting hole 712, second adapter portion 72, second outer side surface 721, second inner side surface 722, explosion-proof disk 80, first lower plastic 10, first body 11, first top surface 111, first bottom surface 112, first limiting column 113, first groove 12, first convex portion 13, first surface 131, first convex rib 141, second convex rib 142, first boss 15, first limiting protrusion 16, first convex surface 161, first installation groove 17, first groove bottom wall 171, first groove side wall 172, third Groove side wall 173, first pole through hole 18, first positioning column 19, first extension section a, first flow channel F, first channel M, explosion-proof fence 101, vent hole 102, second lower plastic 20, second body 21, second top surface 211, second bottom surface 212, second groove 22, second convex portion 23, second surface 231, third rib 241, fourth rib 242, second boss 25, second limiting protrusion 26, second convex surface 261, second installation groove 27, second groove bottom wall 271, second groove side wall 272, fourth groove side wall 273, second Pole through hole 28, second positioning column 29, second limiting column 213, second extension section b, second flow channel G, second channel N, battery cell 300, battery cell body 310, first side surface 311, second side surface 312, top surface 313, bottom surface 314, first pole ear 320, second pole ear 330, protective film 400, assembly port 401, first gap H1, second gap H2, first electrical equipment 3000, second electrical equipment 2000, first electric energy conversion device 4100, second electric energy conversion device 4200, energy storage system 5000. DETAILED DESCRIPTION

[0041] 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.

[0042] In this application, unless otherwise specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, they can be fixedly connected, detachably connected, or integrated; they can be mechanically connected, electrically connected, or able to communicate with each other; they can be directly connected, or indirectly connected through an intermediate medium, and they can be internally connected between two elements or the interaction relationship between two elements, unless otherwise specified and limited. And the terms "same", "equal" or "parallel" used in the following text are allowed to have a certain tolerance.

[0043] It should be noted that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include at least one of the features.

[0044] Since the energy people need is highly temporal and spatial, in order to rationally utilize energy and improve energy utilization, it is necessary to use a medium or device to store one form of energy in the same form or convert it into another form of energy, and then release it in a specific form of energy based on future application needs. As we all know, the main way to generate green electricity is to develop green energy such as photovoltaics and wind power to replace fossil energy. At present, the generation of green electricity generally relies on photovoltaics, wind power, water potential, etc., while wind power and solar energy generally have problems of strong intermittency and large volatility, which will cause instability of the power grid, insufficient electricity during peak hours, too much electricity during low hours, and unstable voltage will also cause damage to electricity. Therefore, it may be due to insufficient electricity demand or insufficient grid acceptance capacity. To solve these problems, energy storage must be relied on. That is, electrical energy is converted into other forms of energy by physical or chemical means and stored, and energy is converted into electrical energy and released when needed. In simple terms, energy storage is similar to a large "power bank". When photovoltaic and wind energy are sufficient, electrical energy is stored and the stored electricity is released when needed.

[0045] Taking electrochemical energy storage as an example, the present application provides an energy storage device 1000, which has a group of chemical batteries inside. The energy storage device 1000 mainly uses the chemical elements in the chemical batteries as energy storage media. The charging and discharging process is accompanied by chemical reactions or changes in the energy storage media. Simply put, the electricity generated by wind energy and solar energy is stored in chemical batteries. When the use of external electricity reaches a peak, the stored electricity is released for use, or transferred to places where electricity is scarce for use.

[0046] At present, energy storage (i.e., energy storage) has a wide range of application scenarios, including (wind and solar) power generation side energy storage, grid side energy storage, base station side energy storage, and user side energy storage. The corresponding types of energy storage devices 1000 include:

[0047] (1) Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, achieve load matching of electric energy in time and space, enhance the ability to absorb renewable energy, and are of great significance in grid system backup, relieving peak load power supply pressure, and peak and frequency regulation;

[0048] (2) Small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side mainly operate in the "peak shaving and valley filling" mode. Since there is a large price difference in electricity prices at peak and valley locations according to electricity demand, after users have energy storage equipment, in order to reduce costs, they usually charge the energy storage cabinets / boxes during the low electricity price period; during the peak electricity price period, the electricity in the energy storage equipment is discharged for use to achieve the purpose of saving electricity bills.

[0049] It should be noted that the above-mentioned energy storage containers, small and medium-sized energy storage cabinets, household small energy storage boxes and other equipment containing the energy storage device 1000 can be understood as electrical equipment.

[0050] See also Figure 1 , Figure 1 It is an application scenario diagram of the energy storage device provided in the embodiment of the present application.

[0051] The energy storage device 1000 provided in the embodiment of the present application is applied to an energy storage system 5000, which includes a first power conversion device 4100 (photovoltaic panel), a second power conversion device 4200 (wind turbine), a first power user 3000 (grid), a second power user 2000 (base station) and an energy storage device 1000. The energy storage system 5000 also includes an energy storage cabinet, and the energy storage device 1000 is installed in the energy storage cabinet, which can be installed outdoors. Specifically, the first power conversion device 4100 can convert solar energy into electrical energy during the period of low electricity prices, and the energy storage device 1000 is used to store the electrical energy and supply the first power user 3000 or the second power user 2000 during peak electricity consumption, or to supply power when the first power user 3000 or the second power user 2000 is powered off / out of power. The second power conversion device 4200 can convert wind energy into electric energy, and the energy storage device 1000 is used to store the electric energy and supply it to the first power device 3000 or the second power device 2000 during peak power consumption, or to supply power when the first power device 3000 or the second power device 2000 is powered off / out of power. The transmission of electric energy can be carried out using a high-voltage cable.

[0052] It should be noted that the first power-consuming device 3000, the second power-consuming device 2000 and other devices including the energy storage device 1000 can be understood as power-consuming devices. The energy storage device 1000 supplies power to the power-consuming devices.

[0053] There may be multiple energy storage devices 1000, and multiple energy storage devices 1000 are connected in series or in parallel. In this embodiment, "multiple" means two or more.

[0054] It can be understood that the energy storage device 1000 may include but is not limited to single cells, battery modules, battery packs, battery systems, etc. The actual application form of the energy storage device 1000 provided in the embodiment of the present application may be, but is not limited to, the listed products, and may also be other application forms. For example, the energy storage device 1000 may be a secondary battery such as a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid (or lead-acid) battery, a lithium-ion battery, a polymer lithium-ion battery, etc. When the energy storage device 1000 is a single cell, it may be a cylindrical battery, a square battery, or a battery of other shapes. In this embodiment, the energy storage device 1000 is a square battery. Among them, the square battery is a secondary battery.

[0055] Please also read Figure 2 , Figure 3 and Figure 4 , Figure 2 is a schematic diagram of the structure of the energy storage device provided in the embodiment of the present application, Figure 3 for Figure 2 The schematic diagram of the exploded structure of the energy storage device shown in FIG. Figure 4 for Figure 2The schematic diagram of the structure of the partial structure of the energy storage device shown. It should be noted that Figure 4 It only illustrates the assembly structure of the protective film, the battery cell, and the first pin and the second pin, rather than indicating the assembly order.

[0056] For ease of description, the width direction of the energy storage device 1000 is defined as the X-axis direction, the length direction is defined as the Y-axis direction, and the height direction is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are mutually perpendicular.

[0057] The directional terms such as "upper", "top", "lower", "bottom", "left", and "right" mentioned in the description of the embodiments of the present application are based on the Figure 2 The description of the orientation shown does not constitute a limitation on the actual application scenario of the energy storage device 1000. Specifically, the positive direction toward the Z axis is the top of the energy storage device 1000, and the negative direction toward the Z axis is the bottom of the energy storage device 1000.

[0058] like Figure 2 and Figure 3 As shown, the energy storage device 1000 includes a shell 200, an end cap assembly 100, a battery cell 300 and a protective film 400. The shell 200 has an opening 201 and is provided with a accommodating cavity 202. The opening 201 is connected to the accommodating cavity 202. The battery cell 300 and the protective film 400 are both accommodated in the accommodating cavity 202. The protective film 400 is arranged between the battery cell 300 and the shell 200. The protective film 400 is coated on the circumference and bottom of the battery cell 300. The protective film 400 is used to protect the battery cell 300 and insulate the battery cell 300 from the shell 200 to prevent the battery cell 300 from short-circuiting with the shell 200. The end cap assembly 100 is installed at one end of the battery cell 300 and is sealed at the opening 201 to isolate the internal environment of the energy storage device 1000 from the external environment. The edge of the end cap assembly 100 facing the battery cell 300 is connected to the protective film 400.

[0059] In this embodiment, the battery cell 300 is a laminated structure. The battery cell 300 includes a battery cell body 310 and a tab. The battery cell body 310 is formed by stacking a positive electrode sheet, a negative electrode sheet, and an insulating film located between the positive electrode sheet and the negative electrode sheet. Both the positive electrode sheet and the negative electrode sheet include a first portion coated with an active material and a second portion extending outward from the first portion and not coated with the active material. The battery cell body 310 includes a first side surface 311 and a second side surface 312. Along the length direction of the battery cell body 310 (i.e., the Y-axis direction), the first side surface 311 and the second side surface 312 are arranged opposite to each other. The battery cell body 310 also includes a top surface 313 and a bottom surface 314. Along the height direction of the battery cell body 310 (i.e., the Z-axis direction), the top surface 313 and the bottom surface 314 are arranged opposite to each other. The top surface 313 and the bottom surface 314 are connected between the first side surface 311 and the second side surface 312. In this embodiment, the number of battery cell bodies 310 is two. The two battery cell bodies 310 are connected in parallel along the Y-axis direction.

[0060] The pole tabs include a first pole tab 320 and a second pole tab 330. The first pole tab 320 and the second pole tab 330 are both electrically connected to the battery cell body 310. Along the Y-axis direction, the first pole tab 320 is led out from the first side 311 of the battery cell body 310. The second pole tab 330 is led out from the second side 312 of the battery cell body 310. In this embodiment, the first pole tab 320 can be a positive pole tab, and the second pole tab 330 can be a negative pole tab. Among them, the positive pole tab corresponds to the second part of the positive electrode sheet that is not coated with the active material. The negative pole tab corresponds to the second part of the negative electrode sheet that is not coated with the active material. The number of the first pole tab 320 and the second pole tab 330 is two. In other embodiments, the first pole tab 320 can be a negative pole tab, and the second pole tab 330 can be a positive pole tab.

[0061] In this embodiment, the protective film 400 is a Mylar film. In some embodiments, the protective film 400 can also be made of insulating materials, such as polyethylene (PE), polypropylene (PP), polyester, etc. The protective film 400 is coated on the first side surface 311, the second side surface 312, the bottom surface 314 and the two surfaces of the battery body 310 in the thickness direction.

[0062] The end cap assembly 100 includes an end cap 30, a lower plastic, a first pole 40, a second pole 50, a first pin 60, and a second pin 70. The lower plastic and the end cap 30 are stacked along the Z-axis direction. The length of the lower plastic is substantially the same as the length of the end cap 30. The width of the lower plastic is substantially the same as the width of the end cap 30. The first pole 40 and the second pole 50 are respectively located at opposite ends of the length direction of the end cap assembly 100. The first pole 40 is inserted through the end cap 30 and the lower plastic, and is connected to the first pin 60. The second pole 50 is inserted through the end cap 30 and the lower plastic, and is connected to the second pin 70. Figure 2 and Figure 3 As shown, the first pin 60 and the second pin 70 are respectively located at opposite ends of the length direction (i.e., the Y-axis direction) of the battery cell 300. The first pin 60 is partially installed on the side of the lower plastic facing away from the end cover 30, and the other part of the first pin 60 is stacked with the first pole ear 320 and connected to the first pole ear 320. The first pole ear 320 is electrically connected to the first pole column 40 through the first pin 60. The second pin 70 is partially installed on the side of the lower plastic facing away from the end cover 30, and the other part of the second pin 70 is stacked with the second pole ear 330 and connected to the second pole ear 330. The second pole ear 330 is electrically connected to the second pole column 50 through the second pin 70. The end cover assembly 100 also includes an explosion-proof valve, which includes an explosion-proof disc 80 and an explosion-proof fence 101. The explosion-proof disc 80 is installed on the end cover 30, and the explosion-proof fence 101 is installed on the lower plastic. The explosion-proof valve is used for explosion-proof pressure relief of the energy storage device 1000. In this embodiment, the end cap 30 is a bare aluminum part, and the lower plastic is made of plastic material and is insulated. The first pole 40 is a positive pole, and the second pole 50 is a negative pole. In other embodiments, the first pole 40 is a negative pole, and the second pole 50 is a positive pole.

[0063] The lower plastic includes a first lower plastic 10 and a second lower plastic 20. In this embodiment, the first lower plastic 10 and the second lower plastic 20 are split structures. In other embodiments, the first lower plastic 10 and the second lower plastic 20 can also be an integrated structure.

[0064] Please refer to Figure 5 and Figure 6 , Figure 5 for Figure 3 The schematic diagram of the structure of the first lower plastic of the end cover assembly in the energy storage device shown, Figure 6 for Figure 5 The schematic diagram of the structure of the first lower plastic is shown at another angle.

[0065] In this embodiment, the first lower plastic 10 is a long thin plate. The first lower plastic 10 includes a first body 11. The first body 11 includes a first top surface 111 and a first bottom surface 112. The first top surface 111 and the first bottom surface 112 are arranged opposite to each other along the thickness direction (ie, the Z-axis direction) of the first body 11.

[0066] The first lower plastic 10 also includes a first groove 12. The first groove 12 is recessed in the first bottom surface 112 of the first body 11. Along the thickness direction (i.e., the Z-axis direction) of the first lower plastic 10, the first groove 12 is recessed from the first bottom surface 112 to the first top surface 111, and protrudes from the first top surface 111 to form a first convex portion 13. It can be understood that the first lower plastic 10 includes a first convex portion 13. Along the Z-axis direction, the first convex portion 13 is convexly disposed on the first top surface 111 of the first body 11. The orthographic projection of the first convex portion 13 on the first bottom surface 112 completely covers the first groove 12. The first convex portion 13 is used to limit and fix with the end cover 30. The first convex portion 13 includes a first surface 131. Along the thickness direction of the first lower plastic 10, the first surface 131 and the bottom wall of the first groove 12 are arranged in reverse. In this embodiment, the first groove 12 is a long strip groove. The first convex portion 13 is a long strip protrusion. The lengths of the first groove 12 and the first protrusion 13 are both smaller than the length of the first lower plastic 10 . The widths of the first groove 12 and the first protrusion 13 are smaller than the width of the first lower plastic 10 .

[0067] The first lower plastic 10 has an explosion-proof fence 101. The explosion-proof fence 101 is arranged on the first convex portion 13. The explosion-proof fence 101 has a plurality of air holes 102. Along the thickness direction of the first lower plastic 10, the plurality of air holes 102 all penetrate the first convex portion 13. It can be understood that the air holes 102 penetrate both sides of the thickness direction of the first lower plastic 10. The air holes 102 are used for gas to pass through. In this embodiment, the air holes 102 are substantially elliptical holes.

[0068] The first lower plastic 10 further includes a first convex rib 141 and a second convex rib 142. The first convex rib 141 and the second convex rib 142 are both convexly disposed on the first bottom surface 112 of the first body 11. Along the width direction of the first lower plastic 10, the first convex rib 141 and the second convex rib 142 are respectively located on opposite sides of the first body 11. The first convex rib 141 and the second convex rib 142 both extend along the length direction of the first lower plastic 10. The lengths of the first convex rib 141 and the second convex rib 142 are both equal to the length of the first lower plastic 10 (a certain process tolerance is allowed).

[0069] The first lower plastic 10 also includes a first boss 15. The first boss 15 is convexly disposed on the first bottom surface 112 of the first body 11. Along the length direction of the first lower plastic 10 (i.e., the Y-axis direction), the first boss 15 is located at one end of the first lower plastic 10 away from the explosion-proof fence 101. Along the width direction of the first lower plastic 10 (i.e., the X-axis direction), the opposite sides of the first boss 15 are respectively opposite to and spaced from the first rib 141 and the second rib 142. A first flow channel F is formed between the first boss 15 and the first rib 141 and the second rib 142, and the first flow channel F is used for the gas inside the energy storage device 1000 to pass through. In this embodiment, the first boss 15 is a roughly rectangular protrusion.

[0070] The first lower plastic 10 also includes a first limiting protrusion 16. The first limiting protrusion 16 is protruded from the first bottom surface 112. Along the Y-axis direction, the first boss 15 and the first limiting protrusion 16 are arranged adjacent to each other. The first limiting protrusion 16 extends along the X-axis direction. The first limiting protrusion 16 is used to contact the battery cell 300. The first limiting protrusion 16 includes a first raised surface 161. Along the Z-axis direction, the first raised surface 161 faces away from the first bottom surface 112. In this embodiment, the first limiting protrusion 16 is roughly a rectangular protrusion. The distance from the first raised surface 161 to the first bottom surface 112 is greater than or equal to 2 mm and less than or equal to 4 mm. That is, the height of the first limiting protrusion 16 protruding from the first bottom surface 112 is greater than or equal to 2 mm and less than or equal to 4 mm. A first channel M is formed between the two end surfaces of the first limiting protrusion 16 along the width direction of the first body 11 and the first convex rib 141 and the second convex rib 142 . The first channel M is connected to the first flow channel F and is used for the gas inside the energy storage device 1000 to pass through.

[0071] The first lower plastic 10 also includes a first mounting groove 17, which is recessed on the surface of the first boss 15 facing away from the first body 11 and is recessed in the direction of the first body 11. The first mounting groove 17 is used to accommodate part of the first pin 60. The first mounting groove 17 includes a first groove bottom wall 171, a first groove side wall 172 and a third groove side wall 173. The orientation of the first groove bottom wall 171 is the same as the orientation of the first raised surface 161. The first groove side wall 172 and the third groove side wall 173 are connected, and the first groove side wall 172 and the third groove side wall 173 are connected to the first groove bottom wall 171. It can be understood that the first groove side wall 172 and the third groove side wall 173 surround the groove peripheral wall of the first mounting groove 17. The first groove side wall 172 is away from the first limiting protrusion 16 and is opposite to the first limiting protrusion 16. The third groove side wall 173 is close to the first limiting protrusion 16. In this embodiment, the surface of the first groove side wall 172 close to the first groove bottom wall 171 is a plane, and the surface of the third groove side wall 173 close to the first groove bottom wall 171 is an arc.

[0072] It can be understood that the surface of the first boss 15 away from the first body 11 can be regarded as the first bottom surface 112, or the first lower plastic 10 does not include the first boss 15, so the first installation groove 17 can be regarded as directly recessed in the first bottom surface 112 and recessed toward the first top surface 111.

[0073] The first lower plastic 10 also includes a first extension section a. Along the Z-axis direction, the first extension section a is convexly disposed on the end surface of the first groove side wall 172 facing away from the first groove bottom wall 171, and the first extension section a extends in a direction away from the first lower plastic 10. The first extension section a and the first limiting protrusion 16 are spaced opposite to each other along the length direction of the first body 11, and the first extension section a is located at the end of the length direction of the first body 11. It can be understood that along the Y-axis direction, the first extension section a is disposed at the edge of the end of the first lower plastic 10 away from the second lower plastic 20. The first extension section a is used to connect with the protective film 400 through a hot melt process.

[0074] The first lower plastic 10 also has a first pole through hole 18. The first pole through hole 18 is used for the first pole 40 to pass through. Along the length direction of the first lower plastic 10, the first pole through hole 18 is spaced apart from the first groove 12. The first pole through hole 18 passes through the first top surface 111 of the first body 11 and the first groove bottom wall 171 of the first mounting groove 17. In this embodiment, the shape of the first pole through hole 18 is roughly a hexagonal hole. In some embodiments, the shape of the first pole through hole 18 can also be a circular, elliptical, etc. This application does not impose strict restrictions on this.

[0075] The first lower plastic 10 also includes a plurality of first positioning columns 19. The plurality of first positioning columns 19 are all protruding from the first groove bottom wall 171. The first positioning columns 19 are spaced apart at the periphery of the first pole through hole 18, and the plurality of first positioning columns 19 are spaced apart from each other. The first positioning column 19 is used to assemble and position the first pin 60. In this embodiment, the first positioning column 19 is cylindrical. The number of the first positioning columns 19 is two. The two first positioning columns 19 are respectively located on both sides of the central axis AA in the length direction of the first lower plastic 10, and the connecting line between the two first positioning columns 19 intersects with the central axis BB in the width direction of the first lower plastic 10. It can be understood that the two first positioning columns 19 are staggered in both the length direction and the width direction of the first lower plastic 10.

[0076] The first lower plastic 10 also includes a plurality of first limiting posts 113, which are protruding from the first top surface 111 of the first body 11. The plurality of first limiting posts 113 are spaced apart at the periphery of the first pole through hole 18, and the plurality of first limiting posts 113 are spaced apart from each other. The first limiting posts 113 are used for assembly and positioning with the end cover 30. In this embodiment, the first limiting posts 113 are cylindrical. The number of the first limiting posts 113 is two. The line between the two first limiting posts 113 is perpendicular to the central axis AA in the length direction of the first lower plastic 10, and the line between the two first limiting posts 113 is parallel to the central axis BB in the width direction of the first lower plastic 10. It can be understood that the first limiting posts 113 are symmetrically arranged with respect to the length direction and the width direction of the first lower plastic 10.

[0077] Please refer to Figure 7 and Figure 8 , Figure 7 for Figure 3 The schematic diagram of the structure of the second lower plastic of the end cover assembly in the energy storage device shown, Figure 8 for Figure 7 The schematic diagram of the structure of the second lower plastic at another angle is shown.

[0078] In this embodiment, the second lower plastic 20 is a long thin plate. The second lower plastic 20 includes a second body 21. The second body 21 includes a second top surface 211 and a second bottom surface 212. The second top surface 211 and the second bottom surface 212 are arranged opposite to each other along the thickness direction (ie, the Z-axis direction) of the second body 21.

[0079] The second lower plastic 20 also includes a second groove 22. The second groove 22 is recessed in the second bottom surface 212 of the second body 21. Along the thickness direction of the second lower plastic 20 (i.e., the Z-axis direction), the second groove 22 is recessed from the second bottom surface 212 to the second top surface 211, and protrudes from the second top surface 211 to form a second convex portion 23. It can be understood that the second lower plastic 20 includes a second convex portion 23. Along the Z-axis direction, the second convex portion 23 is convexly disposed on the second top surface 211 of the second body 21. The orthographic projection of the second convex portion 23 on the second bottom surface 212 completely covers the second groove 22. The second convex portion 23 is used to limit and fix with the end cover 30. The second convex portion 23 includes a second surface 231. Along the thickness direction of the second lower plastic 20, the second surface 231 and the groove bottom wall of the second groove 22 are arranged in reverse. In this embodiment, the second groove 22 is a long strip groove. The second convex portion 23 is a long strip protrusion. The length of the second groove 22 and the second protrusion 23 is smaller than the length of the second lower plastic 20 . The width of the second groove 22 and the second protrusion 23 is smaller than the width of the second lower plastic 20 .

[0080] The second lower plastic 20 further includes a third convex rib 241 and a fourth convex rib 242. The third convex rib 241 and the fourth convex rib 242 are both convexly disposed on the second bottom surface 212 of the second body 21. Along the width direction of the second lower plastic 20, the third convex rib 241 and the fourth convex rib 242 are respectively located on opposite sides of the second body 21. The third convex rib 241 and the fourth convex rib 242 both extend along the length direction of the second lower plastic 20. The lengths of the third convex rib 241 and the fourth convex rib 242 are both equal to the length of the second lower plastic 20 (a certain process tolerance is allowed).

[0081] The second lower plastic 20 also includes a second boss 25. The second boss 25 is convexly disposed on the second bottom surface 212 of the second body 21. Along the length direction of the second lower plastic 20 (i.e., the Y-axis direction), the second boss 25 is located at one end of the second lower plastic 20 away from the second groove 22. Along the width direction of the second lower plastic 20 (i.e., the X-axis direction), the opposite sides of the second boss 25 are respectively opposite to and spaced from the third rib 241 and the fourth rib 242. A second flow channel G is formed between the second boss 25 and the third rib 241 and the fourth rib 242, and the second flow channel G is used for the gas inside the energy storage device 1000 to pass through. In this embodiment, the second boss 25 is roughly rectangular.

[0082] The second lower plastic 20 also includes a second limiting protrusion 26. The second limiting protrusion 26 is protruded from the second bottom surface 212 of the second body 21. Along the Y-axis direction, the second limiting protrusion 26 is arranged adjacent to the second boss 25. The second limiting protrusion 26 extends along the X-axis direction. The second limiting protrusion 26 is used to contact the battery cell 300. The second limiting protrusion 26 includes a second raised surface 261. Along the Z-axis direction, the second raised surface 261 faces away from the second bottom surface 212. In this embodiment, the second limiting protrusion 26 is roughly a rectangular protrusion. The distance from the second raised surface 261 to the second bottom surface 212 is greater than or equal to 2 mm and less than or equal to 4 mm. That is, the height of the second limiting protrusion 26 protruding from the second bottom surface 212 is greater than or equal to 2 mm and less than or equal to 4 mm. A second channel N is formed between the two end surfaces of the second limiting protrusion 26 along the width direction of the second body 21 and the third rib 241 and the fourth rib 242 . The second channel N is connected to the second flow channel G and is used for the gas inside the energy storage device 1000 to pass through.

[0083] The second lower plastic 20 also includes a second mounting groove 27. The second mounting groove 27 is recessed on the surface of the second boss 25 facing away from the second body 21, and is recessed in the direction of the second body 21. The second mounting groove 27 is used to accommodate part of the second pin 70. The second mounting groove 27 includes a second groove bottom wall 271, a second groove side wall 272 and a fourth groove side wall 273. The orientation of the second groove bottom wall 271 is the same as the orientation of the second raised surface 261. The second groove side wall 272 is connected to the fourth groove side wall 273, and the second groove side wall 272 and the fourth groove side wall 273 are jointly surrounded and connected to the second groove bottom wall 271. It can be understood that the second groove side wall 272 and the fourth groove side wall 273 surround the groove peripheral wall of the second mounting groove 27. The second groove side wall 272 is away from the second limiting protrusion 26 and is opposite to the second limiting protrusion 26. The second groove side wall 272 is close to the second limiting protrusion 26. In this embodiment, the surface of the second groove side wall 272 close to the second groove bottom wall 271 is a plane, and the surface of the fourth groove side wall 273 close to the second groove bottom wall 271 is an arc.

[0084] It can be understood that the surface of the second boss 25 away from the second body 21 can be regarded as the second bottom surface 212, or the second lower plastic 20 does not include the second boss 25, so the second installation groove 27 can be regarded as directly recessed in the second bottom surface 212 and recessed toward the second top surface 211.

[0085] The second lower plastic 20 also includes a second extension section b. Along the Z-axis direction, the second extension section b is convexly arranged on the end surface of the second groove side wall 272 facing away from the second groove bottom wall 271, and the second extension section b extends in a direction away from the second lower plastic 20. The second extension section b and the second limiting protrusion 26 are spaced and opposite to each other along the length direction of the second body 21, and the second extension section b is located at the end of the length direction of the second body 21. It can be understood that along the Y-axis direction, the second extension section b is arranged at the edge of the end of the second lower plastic 20 facing away from the first lower plastic 10. The second extension section b is used to connect with the protective film 400 through a hot melt process.

[0086] The second lower plastic 20 also has a second pole through hole 28. The second pole through hole 28 is used for the second pole 50 to pass through. Along the length direction of the second lower plastic 20, the second pole through hole 28 is spaced apart from the second groove 22. The second pole through hole 28 passes through the second top surface 211 of the second body 21 and the second groove bottom wall 271 of the second mounting groove 27. In this embodiment, the shape of the second pole through hole 28 is roughly a hexagonal hole. In some embodiments, the shape of the second pole through hole 28 can also be a circular, elliptical, etc. This application does not impose strict restrictions on this.

[0087] The second lower plastic 20 also includes a plurality of second positioning columns 29. The plurality of second positioning columns 29 are all convexly disposed on the second groove bottom wall 271. The second positioning columns 29 are spaced apart at the periphery of the second pole through hole 28, and the plurality of second positioning columns 29 are spaced apart from each other. The second positioning columns 29 are used to assemble and position the second pin 70. In this embodiment, the second positioning columns 29 are cylindrical. The number of the second positioning columns 29 is two. The two second positioning columns 29 are respectively located on both sides of the central axis CC in the length direction of the second lower plastic 20, and the line between the two second positioning columns 29 is parallel to the central axis DD in the width direction of the second lower plastic 20. It can be understood that the two second positioning columns 29 are symmetrically disposed in the length direction and the width direction of the second lower plastic 20.

[0088] The second lower plastic 20 also includes a plurality of second limiting posts 213. The plurality of second limiting posts 213 are convexly disposed on the second top surface 211 of the second body 21. The plurality of second limiting posts 213 are spaced apart at the periphery of the second pole through hole 28, and the plurality of second limiting posts 213 are spaced apart from each other. The second limiting posts 213 are used for assembly and positioning with the end cover 30. In this embodiment, the second limiting posts 213 are cylindrical. The number of the second limiting posts 213 is two. The line between the two second limiting posts 213 is perpendicular to the central axis AA in the length direction of the second lower plastic 20, and the line between the two second limiting posts 213 is parallel to the central axis BB in the width direction of the second lower plastic 20. It can be understood that the second limiting posts 213 are symmetrically disposed with respect to the length direction and the width direction of the second lower plastic 20.

[0089] Please refer to Figure 3 and Fig. 9 , Fig. 9 for Figure 3 The schematic diagram of the structure of the end cover of the end cover assembly in the energy storage device shown is shown at another angle.

[0090] In this embodiment, the end cover 30 is a long thin plate. The end cover 30 includes an upper surface 31 and a lower surface 32. The upper surface 31 and the lower surface 32 are arranged opposite to each other along the thickness direction (ie, the Z-axis direction) of the end cover 30.

[0091] The end cover 30 includes a first through hole 33 and a second through hole 34. The first through hole 33 penetrates the upper surface 31 and the lower surface 32 along the thickness direction of the end cover 30. The first through hole 33 is used for the first pole 40 to pass through. The second through hole 34 penetrates the upper surface 31 and the lower surface 32. The second through hole 34 is used for the second pole 50 to pass through. Along the length direction of the end cover 30 (i.e., the Y-axis direction), the first through hole 33 and the second through hole 34 are respectively located at opposite ends of the end cover 30. In this embodiment, the shapes of the first through hole 33 and the second through hole 34 are both circular holes.

[0092] The end cap 30 is also provided with a mounting groove 35. The mounting groove 35 is recessed in the lower surface 32 of the end cap 30. Along the thickness direction of the end cap 30, the mounting groove 35 is recessed from the lower surface 32 of the end cap 30 toward the upper surface 31. Along the length direction of the end cap 30, the mounting groove 35 is located between the first through hole 33 and the second through hole 34, and is spaced apart from the first through hole 33 and the second through hole 34. The mounting groove 35 is used to accommodate the first protrusion 13 of the first lower plastic 10 and the second protrusion 23 of the second lower plastic 20. The shape of the mounting groove 35 matches the shape of the first protrusion 13 and the second protrusion 23. In this embodiment, the mounting groove 35 is a long strip groove.

[0093] The end cover 30 further includes an explosion-proof hole 36. Along the thickness direction of the end cover 30, the explosion-proof hole 36 penetrates the upper surface 31 of the end cover 30 and the bottom wall of the assembly groove 35. Along the length direction of the end cover 30, the explosion-proof hole 36 is located between the first through hole 33 and the second through hole 34. The explosion-proof hole 36 is used to install the explosion-proof disk 80. It can be understood that the explosion-proof disk 80 covers the explosion-proof hole 36 and is welded to the edge of the explosion-proof hole 36.

[0094] The end cover 30 further includes a plurality of first limiting grooves 37 and a plurality of second limiting grooves 38. The first limiting grooves 37 are recessed in the lower surface 32, and along the thickness direction of the end cover 30, the first limiting grooves 37 are recessed from the lower surface 32 to the upper surface 31. A plurality of first limiting grooves 37 are arranged at intervals on the periphery of the first through hole 33, and a plurality of first limiting grooves 37 are arranged at intervals from each other. The first limiting grooves 37 are used to accommodate the first limiting columns 113 of the first lower plastic 10. In this embodiment, the shape of the first limiting grooves 37 matches the shape of the first limiting columns 113. The number of the first limiting grooves 37 is two. The two first limiting grooves 37 are respectively located on both sides of the central axis EE in the length direction of the end cover 30, and the connecting line of the centers of the two first limiting grooves 37 is parallel to the central axis FF in the width direction of the end cover 30. It can be understood that the first limiting grooves 37 are symmetrically arranged in the width direction and the length direction of the first lower plastic 10.

[0095] The structure of the second limiting groove 38 is the same as that of the first limiting groove 37. The second limiting groove 38 is recessed in the lower surface 32 along the thickness direction of the end cover 30. The second limiting groove 38 is used to accommodate the second limiting column 213 of the second lower plastic 20. In this embodiment, the number of the second limiting grooves 38 is two. The two second limiting grooves 38 are respectively located on both sides of the central axis EE in the length direction of the end cover 30, and the line connecting the centers of the two second limiting grooves 38 is parallel to the central axis FF in the width direction of the end cover 30. It can be understood that the second limiting grooves 38 are symmetrically arranged in the width direction and the length direction of the second lower plastic 20.

[0096] In some embodiments, a protective member (not shown) is provided on the upper surface 31 of the end cap 30. The protective member completely covers the upper surface 31 of the end cap 30. The protective member is used to protect the end cap 30 to prevent the end cap 30 from being scratched and affecting the use of the end cap 30.

[0097] See also Fig.10 , Fig.10 for Figure 3 A schematic diagram of the structure of the first pin and the second pin of the end cover assembly in the energy storage device. It should be noted that, in this embodiment, the first pin 60 and the second pin 70 are both metal sheets.

[0098] The first pin 60 includes a first connecting portion 61 and a first adapter portion 62. The first connecting portion 61 and the first adapter portion 62 are connected at an angle to form an L-shaped structure. The first connecting portion 61 is accommodated in the first mounting groove 17 of the first lower plastic 10, and the first connecting portion 61 is used to be fixed and electrically connected to the first pole 40. The first adapter portion 62 is used to be electrically connected to the first pole lug 320 of the battery cell 300. It can be understood that the first pin 60 is used to transfer the current of the battery cell 300 to the first pole 40 via the first adapter portion 62 and the first connecting portion 61 in sequence.

[0099] Specifically, the first connection portion 61 has a first through hole 611. The first through hole 611 penetrates the two surfaces of the first connection portion 61 in the thickness direction (i.e., the Z-axis direction). The first through hole 611 is used for the first pole 40 to pass through. The hole wall of the first through hole 611 is connected to the first pole 40. In this embodiment, the shape of the first connection portion 61 matches the shape of the first mounting groove 17. The first through hole 611 is a circular hole.

[0100] The first connection part 61 also has a plurality of first limiting holes 612. The plurality of first limiting holes 612 all penetrate the two surfaces of the first connection part 61 in the thickness direction. The first limiting holes 612 are arranged at intervals on the periphery of the first through-hole 611, and the plurality of first limiting holes 612 are arranged at intervals from each other. Each first limiting hole 612 is used for a first positioning column 19 of the first lower plastic 10 to pass through. In this embodiment, the shape and number of the first limiting holes 612 match the shape and number of the first positioning columns 19, respectively. The shape of the first limiting hole 612 is circular. The number of the first limiting holes 612 is two. The two first limiting holes 612 are respectively located on opposite sides of the central axis in the length direction (i.e., the Y-axis direction) of the first connection part 61. The line connecting the centers of the two first limiting holes 612 intersects with the X-axis.

[0101] In this embodiment, the first adapter portion 62 is a rectangular thin plate. The first adapter portion 62 includes a first outer side surface 621 and a first inner side surface 622. The first outer side surface 621 and the first inner side surface 622 are arranged opposite to each other along the thickness direction (i.e., the Y-axis direction) of the first adapter portion 62. The first outer side surface 621 faces away from the first connecting portion 61 and is used to connect with the first pole tab 320.

[0102] The second pin 70 has a similar structure to the first pin 60. The second pin 70 includes a second connecting portion 71 and a second adapter portion 72. The second connecting portion 71 and the second adapter portion 72 are connected at an angle to form an L-shaped structure. The second connecting portion 71 is accommodated in the second mounting groove 27 of the second lower plastic 20, and the second connecting portion 71 is used to be fixed and electrically connected to the second pole 50. The second adapter portion 72 is used to be electrically connected to the second pole lug 330 of the battery cell 300. It can be understood that the second pin 70 is used to transfer the current of the battery cell 300 to the second pole 50 through the second adapter portion 72 and the second connecting portion 71 in sequence.

[0103] Specifically, the second connecting portion 71 has a second through hole 711. The second through hole 711 penetrates the two surfaces of the second connecting portion 71 in the thickness direction (i.e., the Z-axis direction). The second through hole 711 is used for the second pole 50 to pass through. The hole wall of the second through hole 711 is connected to the second pole 50. In this embodiment, the shape of the second connecting portion 71 matches the shape of the second mounting groove 27. The second through hole 711 is a circular hole.

[0104] The second connection part 71 also has a plurality of second limiting holes 712. The plurality of second limiting holes 712 all penetrate the two surfaces of the second connection part 71 in the thickness direction. The second limiting holes 712 are arranged at intervals on the periphery of the second through hole 711, and the plurality of second limiting holes 712 are arranged at intervals from each other. Each second limiting hole 712 is used for a second positioning column 29 of the second lower plastic 20 to pass through. In this embodiment, the shape and number of the second limiting holes 712 match the shape and number of the second positioning columns 29, respectively. The shape of the second limiting hole 712 is circular. The number of the second limiting holes 712 is two. The two second limiting holes 712 are respectively located on opposite sides of the central axis in the length direction (i.e., the Y-axis direction) of the second connection part 71. The line connecting the centers of the two second limiting holes 712 is parallel to the X-axis.

[0105] In this embodiment, the second adapter portion 72 is a rectangular thin plate. The second adapter portion 72 includes a second outer side surface 721 and a second inner side surface 722. The second outer side surface 721 and the second inner side surface 722 are arranged opposite to each other along the thickness direction (i.e., the Y-axis direction) of the second adapter portion 72. The second outer side surface 721 faces away from the second connecting portion 71 and is used to connect with the second pole tab 330.

[0106] See also Fig.11 , Fig.11 for Figure 3 The schematic diagram of the structure of the partial structure of the energy storage device shown. It should be noted that Fig.11 The assembly structure of the plastic and the first pin 60 and the second pin 70 is only illustrated, rather than indicating the assembly sequence.

[0107] In this embodiment, the first pin 60 is installed on the first lower plastic 10, and the first connecting portion 61 of the first pin 60 is accommodated in the first mounting groove 17 of the first lower plastic 10, and abuts against the first groove bottom wall 171 and the third groove side wall 173 of the first mounting groove 17. The first positioning columns 19 of the two first lower plastics 10 are respectively penetrated through the two first limiting holes 612 of the first connecting portion 61 to limit and fix the first pin 60 to the first lower plastic 10. The first adapter portion 62 extends away from the first lower plastic 10. The first outer side surface 621 of the first adapter portion 62 is opposite to and spaced from the first groove side wall 172 of the first mounting groove 17, forming a first gap H1. The first gap H1 is used to reserve enough space for the first pin 60 and the first pole ear 320 for welding, and is used to accommodate the pre-welding of the first pole ear 320 with different thicknesses with the first adapter portion 62. In this embodiment, the width of the first gap H1 (i.e., the dimension along the Y-axis direction) is greater than or equal to 0.8 mm and less than or equal to 3 mm.

[0108] The second pin 70 is installed on the second lower plastic 20, and the second connecting portion 71 of the second pin 70 is accommodated in the second mounting groove 27 of the second lower plastic 20, and abuts against the second groove bottom wall 271 and the fourth groove side wall 273 of the second mounting groove 27. The second positioning columns 29 of the two second lower plastics 20 are respectively penetrated through the two second limiting holes 712 of the second connecting portion 71 to limit and fix the second pin 70 to the second lower plastic 20. The second adapter portion 72 extends away from the second lower plastic 20. The second outer side surface 721 of the second adapter portion 72 is opposite to and spaced from the second groove side wall 272 of the second mounting groove 27, forming a second gap H2. The second gap H2 is used to reserve enough space for the second pin 70 and the second pole ear 330 for welding, and is used to accommodate the second pole ear 330 of different thicknesses for pre-welding with the second adapter portion 72. In this embodiment, the width of the second gap H2 (ie, the dimension along the Y-axis direction) is greater than or equal to 0.2 mm and less than or equal to 2.5 mm (a certain process tolerance is allowed).

[0109] It should be noted that since the line between the two first positioning posts 19 of the first lower plastic 10 intersects with the central axis BB in the width direction of the first lower plastic 10, and the line between the two second positioning posts 29 of the second lower plastic 20 is parallel to the central axis DD in the width direction of the second lower plastic 20, when the first pin 60 and the second pin 70 are installed in the lower plastic, the first pin 60 will not be mistakenly installed in the second lower plastic 20, and the second pin 70 will not be mistakenly installed in the first lower plastic 10, thereby playing a fool-proof role in the assembly process of the first pin 60 and the second pin 70.

[0110] Please also read Fig.12 , Fig.13 and Fig.14 , Fig.12 for Figure 2 A partial cross-sectional structural diagram of the energy storage device shown in FIG. Fig.13 for Fig.12 The enlarged view of the energy storage device at Q is shown. Fig.14 for Fig.12 An enlarged view of location W of the energy storage device shown.

[0111] In this embodiment, the first pole 40 , the second pole 50 , the first pin 60 , the second pin 70 , the first lower plastic 10 and the second lower plastic 20 are installed together on the end cover 30 to form an end cover assembly 100 .

[0112] Specifically, along the Y-axis direction, the first lower plastic 10 is located at one end of the second lower plastic 20 away from the second boss 25, and the end of the first lower plastic 10 away from the first boss 15 is connected to one end of the second lower plastic 20 away from the second boss 25. The first top surface 111 of the first lower plastic 10 and the second top surface 211 of the second lower plastic 20 face the same direction and are both connected to the lower surface 32 of the end cover 30. The first convex portion 13 of the first lower plastic 10 and the second convex portion 23 of the second lower plastic 20 are both accommodated in the assembly groove 35 of the end cover 30, and the first surface 131 of the first convex portion 13 and the second surface 231 of the second convex portion 23 are both in contact with the bottom wall of the assembly groove 35, so that the first lower plastic 10 and the second lower plastic 20 are limitedly fixed on the end cover 30, so as to avoid displacement of the first lower plastic 10 and the second lower plastic 20 relative to the end cover 30, which affects the reliability of the energy storage device 1000. Along the Z-axis direction, the explosion-proof fence 101 of the first lower plastic 10 is opposite to and spaced from the explosion-proof disc 80, and forms an explosion-proof valve of the end cover assembly 100. The explosion-proof disc 80 completely covers the multiple air holes 102 in the explosion-proof fence 101 in the orthographic projection of the first lower plastic 10, so that the gas can quickly flow to the explosion-proof disc 80 through the air holes 102. The first pole through hole 18 of the first lower plastic 10 is coaxially arranged with the first through hole 33 of the end cover 30. That is, the first through hole 611 of the first pin 60 is coaxially arranged with the first through hole 33. The first pole 40 passes through the first through hole 33, the first pole through hole 18 and the first through hole 611 in sequence. The peripheral side of the first pole 40 abuts against the hole wall of the first through hole 611. The first pole 40 is fixed to the first connecting portion 61 by laser welding to achieve electrical conduction between the first pole 40 and the first pin 60. The first pole 40 is insulated and sealed from the end cover 30 by an insulating member (not shown), which not only prevents a short circuit between the first pole 40 and the end cover 30 , but also prevents the electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000 .

[0113] The second pole through hole 28 of the second lower plastic 20 is coaxially arranged with the second through hole 34 of the end cover 30. That is, the second through hole 711 of the second pin 70 is coaxially arranged with the second through hole 34. The second pole 50 passes through the second through hole 34, the second pole through hole 28 and the second through hole 711 in sequence. The peripheral side of the second pole 50 abuts against the hole wall of the second through hole 711. The second pole 50 is fixed to the second connecting portion 71 by laser welding to achieve electrical conduction between the second pole 50 and the second pin 70. The second pole 50 is insulated and sealed from the end cover 30 by an insulating member (not marked in the figure), which not only prevents the second pole 50 from short-circuiting with the end cover 30, but also prevents the electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000.

[0114] It should be noted that the length of the first lower plastic 10 is greater than the length of the second lower plastic 20. The width of the first lower plastic 10 is equal to the width of the second lower plastic 20. The sum of the length of the first lower plastic 10 and the length of the second lower plastic 20 is equal to the length of the lower plastic. The first body 11 of the first lower plastic 10 and the second body 21 of the second lower plastic 20 are connected to form the body of the lower plastic. The first top surface 111 of the first lower plastic 10 and the second top surface 211 of the second lower plastic 20 form the top surface of the lower plastic. The first bottom surface 112 of the first lower plastic 10 and the second bottom surface 212 of the second lower plastic 20 form the bottom surface of the lower plastic. The first convex rib 141 of the first lower plastic 10 is connected to the third convex rib 241 of the second lower plastic 20, and the second convex rib 142 of the first lower plastic 10 is connected to the fourth convex rib 242 of the second lower plastic 20, thereby forming two convex ribs located in the width direction of the lower plastic respectively. The lengths of the two convex ribs are equal to the length of the lower plastic. The first convex portion 13 of the first lower plastic 10 and the second convex portion 23 of the second lower plastic 20 are connected and spliced ​​to form a convex portion. The first concave groove 12 of the first lower plastic 10 and the second concave groove 22 of the second lower plastic 20 are connected and spliced ​​to form a concave groove. The depth of the second concave groove 22 is equal to the depth of the first concave groove 12 (a certain process tolerance is allowed).

[0115] The end cap assembly 100 is assembled with the battery cell 300. The first convex surface 161 of the first limiting protrusion 16 and the second convex surface 261 of the second limiting protrusion 26 are in contact with the top surface 313 of the battery cell body 310, preventing the multiple positive and negative electrode sheets constituting the battery cell 300 from being misaligned or offset, and playing a role in fixing and limiting the battery cell 300 as a whole. The first extension section a of the first lower plastic 10 and the second extension section b of the second lower plastic 20 extend toward the battery cell 300.

[0116] The first pin 60 and the second pin 70 are connected to the battery cell 300. Along the Z-axis direction, the first connection portion 61 of the first pin 60 and the second connection portion 71 of the second pin 70 are spaced apart from the battery cell body 310 to avoid the first connection portion 61 and the second connection portion 71 being connected to the battery cell body 310 and causing a short circuit. The first adapter portion 62 of the first pin 60 is connected to the first pole ear 320. The first inner side surface 622 of the first adapter portion 62 faces the first side surface 311 of the battery cell body 310. The first pole ear 320 extends from the first side surface 311 of the battery cell body 310 to the side of the first adapter portion 62 facing away from the battery cell body 310, and is welded to the first outer side surface 621 of the first adapter portion 62 to achieve electrical conduction between the first pole ear 320 and the first pin 60.

[0117] The second adapter portion 72 of the second pin 70 is connected to the second pole tab 330. The second inner side surface 722 of the second adapter portion 72 faces the second side surface 312 of the cell body 310. The second pole tab 330 extends from the second side surface 312 of the cell body 310 to the side of the second adapter portion 72 facing away from the cell body 310, and is welded to the second outer side surface 721 of the second adapter portion 72, so as to realize electrical conduction between the second pole tab 330 and the second pin 70.

[0118] It should be noted that the length of the first transition portion 62 is shorter than the length of the first electrode tab 320 . The length of the second transition portion 72 is shorter than the length of the second electrode tab 330 .

[0119] Combination Figure 3 and Figure 4As shown, the circumference and bottom of the battery cell 300 are wrapped by the protective film 400. Specifically, the first side surface 311 and the second side surface 312 of the battery cell body 310, the two surfaces in the width direction of the battery cell body 310 and the bottom surface 314, the first pole ear 320, the second pole ear 330, the first transition part 62 and the second transition part 72 are all covered by the protective film 400. It can be understood that the protective film 400 forms a cylindrical structure and has an assembly opening 401. The protective film 400 at the edge of the assembly opening 401 is connected to the edge of the lower plastic. Specifically, the protective film 400 at the edge of the assembly opening 401 is connected to the first groove side wall 172, the first rib 141, the second rib 142, the third rib 241, the fourth rib 242 and the second groove side wall 272, and is connected to the first extension section a on the first groove side wall 172, the first rib 141, the second rib 142, the second extension section b on the second groove side wall 272, the third rib 241 and the fourth rib 242 through a hot melt process to achieve the fixation of the protective film 400 and the lower plastic. The battery cell 300 wrapped with the protective film 400 is accommodated in the accommodating cavity 202 of the shell 200. The protective film 400 insulates the battery cell 300 and the shell 200 to prevent the battery cell 300 and the shell 200 from short-circuiting. The edge of the end cover 30 is connected to the edge of the opening 201 of the shell 200 by welding or the like to seal the energy storage device 1000.

[0120] It should be noted that when the energy storage device 1000 experiences thermal runaway, a large amount of gas will be generated inside the energy storage device 1000. The gas flows from both sides of the width direction of the battery cell 300 through the first flow channel F and the first channel M of the first lower plastic 10 and the second flow channel G and the second channel N of the second lower plastic 20, and passes through the air vents 102 of the explosion-proof fence 101 to flow to the explosion-proof hole 36, and breaks through the explosion-proof plate 80 to be discharged from the energy storage device 1000, thereby accelerating the gas flow rate inside the energy storage device 1000, avoiding the accumulation of gas inside the energy storage device 1000 and being unable to be discharged in time, and improving the safety and reliability of the energy storage device 1000.

[0121] In the related art, the battery cell is usually laminated or wound. When the battery cell is laminated, the positive and negative tabs of the battery cell are generally led out from the same side or opposite sides of the laminated battery cell, and the positive and negative pins in the end cap assembly need to be welded to the positive and negative tabs respectively. However, the lower plastic structure in the existing end cap assembly is not convenient for installation with the positive and negative pins.

[0122] In the embodiment of the present application, the first lower plastic 10 includes a first boss 15, the first boss 15 is provided with a first mounting groove 17, the first mounting groove 17 is matched with the first pin 60, and the first groove side wall 172 of the first mounting groove 17 and the first transition portion 62 of the first pin 60 have a first gap H1, which is reserved for the assembly of the first pin 60 and the first tab 320. Similarly, the second lower plastic 20 includes a second boss 25, the second boss 25 is provided with a second mounting groove 27, the second mounting groove 27 is matched with the second pin 70, and the second groove side wall 272 of the second mounting groove 27 and the second transition portion 72 of the second pin 70 have a second gap H2, which is reserved for the assembly of the second pin 70 and the second tab 330.

[0123] The two first positioning posts 19 of the first lower plastic 10 intersect with the central axis BB in the width direction of the first lower plastic 10, and the two second positioning posts 29 of the second lower plastic 20 are parallel to the central axis DD in the width direction of the second lower plastic 20, which not only provide a positioning reference for the first pin 60 and the second pin 70, but also play a fool-proof role when assembling the first pin 60 and the second pin 70, facilitating the assembly of the first pin 60 and the second pin 70 with the lower plastic.

[0124] The above are only some embodiments and implementation methods of the present application, and the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by any person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An energy storage device, characterized in that: include: a housing including an opening; A battery cell, comprising a battery cell body and a tab, wherein the battery cell body comprises a side surface and a top surface connected to the side surface, and the tab is led out from the side surface and connected to the battery cell body; and The end cap assembly comprises a lower plastic and a pole, wherein the lower plastic comprises a body and a limiting protrusion, wherein the body comprises a top surface and a bottom surface, wherein the top surface and the bottom surface are arranged opposite to each other along the thickness direction of the body, wherein the lower plastic further comprises a boss and a mounting groove, wherein the mounting groove is recessed on the surface of the boss facing away from the bottom surface, wherein the boss is located at the end of the lower plastic in the length direction, wherein the limiting protrusion is arranged adjacent to the boss in the length direction of the lower plastic, and the end surface of the boss facing away from the limiting protrusion is connected to the end surface of the lower plastic body, The lower plastic also includes two convex ribs, both of which are convexly arranged on the bottom surface, and the two convex ribs are respectively located at opposite edges of the bottom surface in the width direction, and the two convex ribs extend along the length direction of the lower plastic body; the boss is located between the two convex ribs, and a flow channel is formed between the boss and the boss, and the end surface of the boss facing away from the limiting protrusion and the end surfaces of the two convex ribs in the length direction are spaced by the flow channel; the limiting protrusion has a channel between the two end surfaces along the width direction of the lower plastic and the two convex ribs, respectively, and the channel is connected to the flow channel for allowing the gas inside the energy storage device to pass through; The end cap assembly further includes a pin, the pin includes a connecting portion and a transition portion, the transition portion is connected to the connecting portion at an angle, the connecting portion is accommodated in the mounting groove, and the transition portion extends away from the bottom surface; The battery cell is installed in the housing, the end cover assembly is encapsulated in the opening, the limiting protrusion is in contact with the top surface of the battery cell facing the opening, the transition portion is stacked on the side and is stacked and connected with the pole ear, the pole passes through the body and the connecting portion, and the pole is conductively connected to the connecting portion, wherein the connecting portion is spaced apart from the top surface of the battery cell; The energy storage device also includes a protective film, which is located between the shell and the battery cell and wraps the bottom and surrounding side of the battery cell. The protective film has an assembly opening, the top surface is located at the assembly opening, and the assembly opening faces the bottom surface; the protective film at the edge of the assembly opening is connected to the convex rib and the side wall of the mounting groove.

2. The energy storage device according to claim 1, characterized in that: The height of the limiting protrusion protruding from the bottom surface is greater than or equal to 2 mm and less than or equal to 4 mm.

3. The energy storage device according to claim 1, characterized in that: The mounting groove comprises a groove bottom wall and a groove side wall connected to the groove bottom wall; Along the length direction of the lower plastic, there is a gap between the surface of the groove side wall facing away from the mounting groove and the limiting protrusion and the surface of the adapter portion facing away from the connecting portion.

4. The energy storage device according to claim 3, characterized in that: The width of the gap is greater than or equal to 0.2 mm and less than or equal to 3 mm.

5. The energy storage device according to claim 3, characterized in that: The lower plastic also includes an extension section, which is convexly arranged on the end surface of the groove side wall facing away from the groove bottom wall, and the extension section and the limiting protrusion are spaced and opposite to each other along the length direction of the body, and the extension section is located at the end of the length direction of the body; The protective film on the periphery of the assembly opening is connected to the extension section through a hot-melt process.

6. The energy storage device according to claim 5, characterized in that: The lower plastic also includes two positioning posts, both of which are convexly arranged on the bottom wall of the groove, and the two positioning posts are staggered along the length direction and width direction of the lower plastic; The connecting portion comprises two limiting holes, both of which penetrate through two surfaces of the connecting portion in a thickness direction, and each of the positioning posts is disposed through one of the limiting holes.

7. The energy storage device according to claim 1, characterized in that: The end cap assembly further comprises an end cap, the end cap and the lower plastic are stacked along the thickness direction of the end cap assembly, and the end cap is located on a side of the lower plastic facing away from the battery cell; The lower plastic also includes an explosion-proof fence, and a plurality of air holes are provided in the explosion-proof fence. The plurality of air holes penetrate the top surface and the bottom surface, and the plurality of air holes are communicated with the flow channel.

8. The energy storage device according to claim 3, characterized in that: The side surface includes a first side surface and a second side surface, the first side surface and the second side surface are arranged opposite to each other along the width direction of the battery body, the pole ear includes a first pole ear and a second pole ear, the first pole ear is led out from the first side surface, and the second pole ear is led out from the second side surface; The pin includes a first pin and a second pin, the first pin includes a first connecting portion and a first transition portion, the first transition portion includes a first outer side surface, the second pin includes a second connecting portion and a second transition portion, the second transition portion includes a second outer side surface, the first outer side surface and the second outer side surface both face away from the battery cell body, the first outer side surface is connected to the first pole lug, and the second outer side surface is connected to the second pole lug; The mounting groove includes a first mounting groove and a second mounting groove, the first connecting portion is accommodated in the first mounting groove, the first mounting groove includes a first groove side wall, a first gap is formed between the first outer side surface and the first groove side wall, and the second mounting groove includes a second groove side wall, a second gap is formed between the second outer side surface and the second groove side wall; The width of the first gap is greater than or equal to 0.8 mm and less than or equal to 3 mm, and the width of the second gap is greater than or equal to 0.2 mm and less than or equal to 2.5 mm.

9. The energy storage device according to claim 8, characterized in that: The first installation slot further includes a first slot bottom wall, and the second installation slot further includes a second slot bottom wall; The lower plastic also includes two first positioning posts and two second positioning posts, the two first positioning posts are both protruding from the bottom wall of the first groove and staggered along the length direction and width direction of the lower plastic, and the two second positioning posts are both protruding from the bottom wall of the second groove and symmetrically arranged along the length direction and width direction of the lower plastic; The first connecting part includes two first limiting holes, both of which penetrate the two surfaces of the first connecting part in the thickness direction, and each of the first positioning columns is arranged in one of the first limiting holes. The second connecting part includes two second limiting holes, both of which penetrate the two surfaces of the second connecting part in the thickness direction, and each of the second positioning columns is arranged in one of the second limiting holes.

10. An electrical device, characterized in that: It comprises an energy storage device as described in any one of claims 1 to 9, and the energy storage device supplies power to the electrical equipment.

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