End cap assembly, energy storage device and energy storage system

Abstract

This application provides an end cap assembly, an energy storage device, and an energy storage system. The end cap assembly includes an end cap, a lower plastic component, and a first support. The lower plastic component further includes a first through groove and a first boss. The first boss protrudes from one side of the lower plastic component along its thickness direction and is located at the end of the lower plastic component along its length direction. The first boss has a boss surface, and the first through groove penetrates the first surface and the boss surface. The first through groove includes a first groove sidewall, a second groove sidewall, and a groove bottom wall. The first groove sidewall and the second groove sidewall are opposite to and spaced apart from each other. The groove bottom wall is connected to the first groove sidewall and spaced apart from the second groove sidewall. The groove bottom wall is provided with a vent hole and a vent groove, and the second groove sidewall is provided with an exhaust hole. The vent groove, the exhaust hole, and the vent hole are all connected to the outside of the first through groove and the lower plastic component, and the vent groove is connected to the vent hole. Along the thickness direction of the end cap assembly, the end cap and the lower plastic component are stacked and connected, with the first surface facing the end cap. The first support is received in the first through groove and fixed to the lower plastic component, and is used to support the end cap.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to an end cap assembly, an energy storage device, and an energy storage system. Background Technology

[0002] With the rapid development of the new energy industry, the market demand for batteries continues to grow. However, when existing batteries experience thermal runaway, a large amount of high-temperature gas is generated inside the battery. During the exhaust process, this high-temperature gas can cause the lower insulation component to melt and deform, or even catch fire. At the same time, the high-temperature gas pushes the battery core upwards towards the lower insulation component, which can easily block the exhaust channel. This makes it difficult for a large amount of gas inside the battery to escape in time, leading to an increase in internal gas pressure and posing a significant safety hazard. Summary of the Invention

[0003] This application provides an end cap assembly, an energy storage device, and an energy storage system, which enhances the venting performance of the end cap assembly and improves the safety performance of the energy storage device.

[0004] In a first aspect, embodiments of this application provide an end cap assembly. The end cap assembly includes: End cap; The lower plastic includes a first surface and a second surface, which are disposed opposite to each other along the thickness direction of the lower plastic. The lower plastic also includes two first through grooves and two first bosses. The two first bosses protrude from the second surface in a direction away from the first surface and are respectively located at both ends of the length direction of the lower plastic. The first boss has a boss surface, which faces the same direction as the second surface. Along the thickness direction of the lower plastic, each first through groove penetrates the first surface and the boss surface. The first channel includes a first channel sidewall, a second channel sidewall, two channel end walls, and a channel bottom wall. The first channel sidewall and the second channel sidewall are opposite to each other and spaced apart along the length direction of the lower plastic. The two channel end walls are opposite to each other and spaced apart along the width direction of the lower plastic and are connected to the first channel sidewall and the second channel sidewall. The channel bottom wall is connected to the first channel sidewall and spaced apart from the second channel sidewall. The channel bottom wall and the boss surface are opposite to each other along the thickness direction of the lower plastic. The lower plastic also includes a vent hole and a vent hole. The vent hole penetrates both sides of the bottom wall of the groove in the thickness direction, and the vent hole penetrates both sides of the side wall of the second groove in the thickness direction. Both the vent hole and the vent hole are connected to the outside of the first through groove and the lower plastic. Two first supports extend along the width direction of the end cap assembly, and the melting point of both first supports is greater than the melting point of the lower plastic. Along the thickness direction of the end cap assembly, the end cap and the lower plastic are stacked and connected, the first surface faces the end cap, each first bracket is received in a first through groove and fixed to the lower plastic, and is used to support the end cap; The lower plastic also includes an air guide groove, which is recessed from the boss towards the bottom wall of the groove and penetrates the wall surface of the first groove sidewall toward the second groove sidewall. Along the thickness direction of the lower plastic, the projection of the air guide groove and the projection of the air guide hole partially coincide, and the air guide groove is connected to the air guide hole, the first through groove and the outside of the lower plastic.

[0005] In one embodiment, along a direction perpendicular to the thickness direction of the end cap assembly, there are assembly gaps between the edge of the first bracket and the first groove sidewall, the two groove endwalls, the groove bottom wall and the second groove sidewall, and the assembly gaps are greater than or equal to 0.1 mm.

[0006] In one embodiment, a first reinforcing rib is connected between the bottom wall of the groove and the side wall of the second groove along the length direction of the lower plastic, and the first reinforcing rib is recessed relative to the boss surface along the thickness direction of the lower plastic.

[0007] In one embodiment, a side plate protrudes from the bottom wall of the tank, the side plate is connected to the first tank side wall and is spaced apart from the second tank side wall along the length of the lower plastic; the first reinforcing rib is connected to the side plate.

[0008] In one embodiment, the first bracket includes a bracket body, which is accommodated in the first through groove and located between the side wall of the second groove and the bottom wall of the groove; Along the thickness direction of the end cap assembly, the bracket body is positioned opposite and spaced apart from the end cap. The surface of the bracket body facing away from the end cap is recessed relative to the boss surface and has a height difference with the boss surface. The height difference is greater than or equal to 0.1 mm and is less than or equal to one-third of the overall height of the first bracket in the thickness direction of the end cap assembly.

[0009] In one embodiment, the first bracket further includes two snap-fit ​​bodies, which protrude from both sides of the bracket body along the length of the first bracket and extend toward the end cap. The bottom wall of the groove is provided with a buckle, which is adjacent to the end wall of the groove, and the snap-fit ​​body is snapped and fixed to the buckle.

[0010] In one embodiment, the first bracket further includes a first leg and a second leg. Along the width direction of the first bracket, the first leg and the second leg are respectively connected to both sides of the bracket body and extend toward the end cap. Along the length direction of the lower plastic, the first leg and the second leg are completely staggered. The bottom wall of the tank is provided with a first clearance notch, which penetrates the bottom wall of the tank and exposes the first side wall of the tank. The second side wall of the tank is provided with a second clearance notch. Along the length of the lower plastic, the first clearance notch and the second clearance notch are completely staggered. The first support leg is accommodated in the first clearance notch, and the second support leg is accommodated in the second clearance notch.

[0011] In one embodiment, the end cap further includes a plurality of positioning grooves, each of which is recessed on the surface of the end cap facing the lower plastic and is spaced apart from each other. Along the thickness direction of the end cap assembly, the ends of the two snap-fit ​​bodies, the first leg, and the second leg that are away from the bracket body protrude above the first surface, and the two snap-fit ​​bodies, the first leg, and the second leg are respectively inserted into a plurality of positioning grooves, and the height of the two snap-fit ​​bodies, the first leg, and the second leg above the first surface is less than or equal to the depth of the positioning grooves.

[0012] In one embodiment, the depth of each positioning groove is greater than or equal to 0.2 mm, and the ratio of the depth of each positioning groove to the thickness of the end cap is less than or equal to 0.5.

[0013] In one embodiment, the plurality of positioning grooves include a plurality of first positioning grooves, a plurality of second positioning grooves and a plurality of third positioning grooves. Along the width direction of the end cap, the plurality of first positioning grooves are spaced apart, the plurality of second positioning grooves are spaced apart, and the plurality of third positioning grooves are spaced apart. The first support leg includes a support leg body and two support bodies. The support leg body is connected to the bracket body and extends along the width direction of the first bracket. Along the length direction of the first bracket, the two support bodies are respectively bent and connected to both sides of the support leg body and extend toward the end cap. Each of the snap-fit ​​bodies is inserted into a third positioning slot, each of the second legs is inserted into a second positioning slot, and each of the supports is inserted into a first positioning slot.

[0014] In one embodiment, the lower plastic further includes a second through groove and a plurality of second protrusions. The second through groove extends through both sides of the lower plastic in the thickness direction. Along the length direction of the lower plastic, the second through groove is located between two first through grooves. The plurality of second protrusions protrude from the second surface in a direction away from the first surface and are disposed on both sides of the second through groove. The plurality of second protrusions are spaced apart along the width direction of the lower plastic and have gaps. The end cap assembly further includes a second bracket, which is received in the second through groove and located between a plurality of second protrusions on both sides of the second through groove. The second bracket is fixed to the lower plastic and supported on the end cap. A ventilation channel is formed between the second bracket and the end cap. The ventilation channel communicates with the gap between the second through groove and the plurality of second protrusions. The length direction of the second bracket extends along the width direction of the end cap assembly, and the melting point of the second bracket is greater than the melting point of the lower plastic.

[0015] In one embodiment, the second bracket has a plurality of third legs spaced apart along the width direction of the end cap assembly, and the plurality of third legs are all supported on the end cap; Along the length of the end cap assembly, each of the third legs is adjacent to a second boss, and the projection of each third leg is completely within the projection of the adjacent second boss.

[0016] In one embodiment, the lower plastic further includes a connecting rib, which protrudes from the second surface and extends along the width direction of the lower plastic. The connecting rib is connected to a plurality of second protrusions on one side of the second through groove in the length direction of the lower plastic, and the connecting rib is located on the side of the plurality of second protrusions facing away from the second through groove. Along the thickness direction of the end cap assembly, the surface of the connecting rib away from the second surface protrudes from the surface of the second bracket opposite to the end cap.

[0017] In one embodiment, the end cap assembly further includes two first insulating members and a second insulating member, each of the first insulating members being located on the side of a first bracket facing away from the end cap and completely covering the first bracket, and the second insulating member being located on the side of a second bracket facing away from the end cap and completely covering the second bracket.

[0018] In one embodiment, the materials of both the first insulating element and the second insulating element include at least one of PI tape, PET tape, PP tape, and PI and PET composite tape.

[0019] In one embodiment, the second bracket includes a vent hole that extends through both sides of the second bracket in the thickness direction. Along the length direction of the end cap assembly, the vent hole has two opposing and spaced-apart first sides, with an opening distance between the two first sides. The second insulating member includes an insulating hole that penetrates both surfaces of the second insulating member in the thickness direction. Along the length direction of the end cap assembly, the insulating hole has two opposing and spaced second sides. The insulating hole and the vent hole are connected and both are connected to the venting channel. Along the thickness direction of the end cap assembly, the projection of the insulating hole is completely located within the projection of the vent hole. Along the length direction of the end cap assembly, the distance between the two second sides is less than the opening distance.

[0020] In one embodiment, along the length of the end cap assembly, each second side is adjacent to one of the first sides and has an assembly distance greater than or equal to 0.1 mm, and the ratio of the assembly distance to the opening distance is less than or equal to 0.4.

[0021] In one embodiment, the assembly distance is greater than or equal to 0.5 mm and less than or equal to 2 mm.

[0022] Secondly, embodiments of this application provide an energy storage device. The energy storage device includes a housing, a battery cell, and an end cap assembly. The battery cell is housed within the housing, and the end cap assembly is mounted on one side of the battery cell in the height direction and sealed to the housing. A lower plastic abuts against the battery cell.

[0023] Thirdly, embodiments of this application provide an energy storage system. The energy storage system includes the aforementioned energy storage device.

[0024] In existing technologies, when a battery experiences thermal runaway, a large amount of high-temperature gas is violently generated inside. This high-temperature gas needs to be expelled from the battery to ensure its safety. During the expulsion of these high-temperature gases, the lower insulation components may melt, deform, or even catch fire. The lower plastic casing loses its supporting function. Simultaneously, the high-temperature gas pushes the battery cells upwards towards the top cover, potentially blocking the venting channels between the cells and the top cover. This makes it difficult for the large amount of gas inside the battery to escape in time, causing the internal gas pressure to rise and potentially leading to battery explosions, casing cracks, and other problems, thus posing a significant safety hazard.

[0025] In this embodiment, the end cap assembly includes two first supports, an end cap, and a lower plastic layer. The end cap and the lower plastic layer are stacked along the thickness direction of the end cap assembly. The lower plastic layer has two first protrusions and two first through slots. The two first protrusions are respectively located at both ends of the lower plastic layer along its length. Each first through slot and one first protrusion are correspondingly provided and penetrate both sides of the lower plastic layer along its thickness direction. The two first protrusions are used to press against the battery cell to separate and insulate the battery cell from the end cap, ensuring an exhaust channel between the battery cell and the end cap. The bottom wall of the first through slot has a vent hole, and the wall surface of the bottom wall facing away from the opening of the first through slot has a recessed vent groove. The vent groove penetrates the wall surface of the first slot sidewall facing the second slot sidewall. The vent groove, vent hole, and first through slot are connected to each other to prevent the vent hole from being blocked and preventing gas from entering the first through slot when the first protrusion abuts against the battery cell. The second slot sidewall of the first through slot has an exhaust hole, which is connected to the first through slot. Gas rising from the side of the battery cell can flow smoothly through the lower plastic end via the gas guide groove, gas guide hole, first through groove, and exhaust hole. Each first bracket is housed in a first through groove and fixed to the lower plastic, and also serves to support the end cap. The melting point of the first bracket is higher than that of the lower plastic. In the event of thermal runaway of the energy storage device, even if the lower plastic fails, the first bracket remains structurally stable. A large amount of gas and the battery cell compress the first bracket, which can effectively support the first bracket between the battery cell and the end cap, ensuring sufficient passage for the rising gas from the side of the battery cell to pass through. This prevents the internal gas of the energy storage device from being unable to escape in time, which could lead to increased gas pressure and subsequently explosions or shell cracking. This improves the exhaust performance of the end cap assembly and enhances the safety of the energy storage device. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments or background art of this application, the accompanying drawings used in the embodiments or background art of this application will be described below.

[0027] Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application; Figure 2 for Figure 1 A schematic diagram of the energy storage device in the energy storage system shown. Figure 3 for Figure 2 The diagram shows the exploded structure of the energy storage device. Figure 4 for Figure 3 A simplified schematic diagram of the assembly of the anode plate, cathode plate, and insulating film of the battery cell in the energy storage device shown. Figure 5 for Figure 3 A schematic diagram of the end cap assembly of the energy storage device shown from another angle; Figure 6 for Figure 5The diagram shows an exploded view of the end cap assembly. Figure 7 for Figure 6 An exploded view of the end cap assembly from another angle; Figure 8 for Figure 7 A schematic diagram of the end cap structure of the end cap assembly shown; Figure 9 for Figure 7 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the diagram, representing a first embodiment; Figure 10 for Figure 9 The diagram shows the structure of the lower plastic at another angle; Figure 11 for Figure 7 The diagram shows the structure of the two first supports and the second support of the end cap assembly. Figure 12 for Figure 11 The diagram shows the structure of the two first supports and the second support from another angle. Figure 13 for Figure 7 The diagram shows the assembly structure of the lower plastic part of the end cap assembly with the two first brackets and the second bracket. Figure 14 for Figure 13 A schematic diagram of the assembly structure shown from another angle; Figure 15 for Figure 13 The diagram shows a cross-sectional view of the assembly structure along AA. Figure 16 for Figure 7 The diagram shows the assembly structure of the end cap assembly with the two first brackets and the second bracket. Figure 17 for Figure 5 The diagram shows a cross-sectional view of the end cap assembly along BB. Figure 18 for Figure 7 A schematic diagram of the structure of the lower plastic of the end cap assembly shown in the second embodiment; Figure 19 for Figure 3 A bottom view of a second embodiment of the second insulating member of the end cap assembly, assembled with a second bracket.

[0028] The terms corresponding to the reference numerals in the figures are as follows: Energy storage system 4000, high-voltage cable 4100, first power conversion device 4200, second power conversion device 4300, energy storage device 1000, housing 200, opening 201, receiving cavity 202, end cap assembly 100, battery cell 300, anode plate 301, cathode plate 302, insulating film 303, end cap 10, lower plastic 20, bracket 40, first bracket 40a, second bracket 40b, insulating component 50, first insulating component 51, second insulating component 52, explosion-proof valve 60, protective plate 70, pole 80, upper plastic 91, sealing ring 92, pressure block. 93. Insulating hole 521, top surface 11, bottom surface 12, first pole hole 13, explosion-proof hole 14, limiting groove 15, positioning groove 16, first positioning groove 16a, second positioning groove 16b, third positioning groove 16c, depth L1 of positioning groove 16, first surface 21, second surface 22, second pole hole 23, first boss 24, boss surface 241, first boss side surface 242, second boss side surface 243, first through groove 25, first groove side wall 251, second groove side wall 252, groove end wall 253, groove bottom wall 254, side plate 255, first sub-wall 254a, second sub-wall 254b, buckle 256. Air vent 26. Air vent groove 27. First clearance notch 28a. Second clearance notch 28b. Exhaust vent 29. Return groove 30. First reinforcing rib 31. Second through groove 32. End wall 321. Second boss 33. Boss surface 331. Groove 35. Third groove sidewall 351. Fourth groove sidewall 352. Bottom wall 353. First groove 35a. Second groove 35b. Hook 36. Second reinforcing rib 37. Limiting post 38. Connecting rib 39. Bracket body a1. Snap-fit ​​body a2. First support leg a3. Second support leg a4. First upper surface a11. First lower surface a12. First side surface a13. Second side a14, first snap-fit ​​surface a21, second snap-fit ​​surface a22, first snap-fit ​​groove a23, support body a31, support body a32, first surface a33, second surface a34, end face a35, bracket body b1, snap-fit ​​section b2, third support foot b3, second upper surface b11, second lower surface b12, third side b13, vent hole b4, third snap-fit ​​surface b21, second snap-fit ​​groove b22, height difference S, height L, thickness H of end cap 10, airflow channel Q1, vent channel Q2, assembly distance T, assembly gap D, opening distance F, second side 522, first side b41. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0030] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly specified. Furthermore, the terms "same," "equal," or "parallel" used below are all allowed to have certain tolerances.

[0031] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of those features.

[0032] Because the energy we need is highly time- and space-dependent, in order to utilize energy rationally and improve energy efficiency, it is necessary to store one form of energy in the same way or by converting it into another, and then release it in a specific energy form for future applications. Currently, the main way to generate green electricity is to develop green energy sources such as photovoltaics and wind power to replace fossil fuels. Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak hours, and excessive power during off-peak hours. Unstable voltage can also damage the power grid. Therefore, due to insufficient electricity demand or insufficient grid capacity, solving these problems requires energy storage. This involves converting electrical energy into other forms of energy through physical or chemical means and storing it. When needed, this energy can be converted back into electrical energy and released. Simply put, energy storage is like a large "power bank," storing electrical energy when solar and wind power are abundant and releasing the stored electricity when needed.

[0033] Taking electrochemical energy storage as an example, this solution provides an energy storage device for use in energy storage systems. The energy storage device is equipped with a set of chemical batteries, which mainly use the chemical elements in the batteries as energy storage media. The charging and discharging process is accompanied by the chemical reaction or change of the energy storage media. Simply put, the electrical energy generated by wind and solar energy is stored in the chemical batteries. When the use of external electrical energy reaches its peak, the stored electricity is released for use, or transferred to places with a shortage of electricity for use.

[0034] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. The corresponding types of energy storage devices include: (1) Large-scale energy storage power stations applied to wind power and photovoltaic power stations can help renewable energy power generation meet grid connection requirements and improve the utilization rate of renewable energy. As a high-quality active / reactive power regulation power source on the power supply side, energy storage power stations can achieve load matching of power in time and space, enhance the absorption capacity of renewable energy, reduce instantaneous power changes, reduce the impact on the power grid, improve the absorption of new energy power generation, and are of great significance in power grid system backup, alleviating peak load power supply pressure and peak regulation and frequency regulation. (2) Energy storage containers applied on the grid side mainly function as peak shaving, frequency regulation and grid congestion relief. In terms of peak shaving, they can realize peak shaving and valley filling of electricity load, that is, charging the energy storage battery when the electricity load is low and releasing the stored electricity during the peak electricity load period, thereby achieving a balance between power production and consumption. (3) Small-scale energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improving power supply reliability. Depending on the application scenario, electricity consumption-side energy storage can be divided into industrial and commercial energy storage cabinets, residential energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaic power. Considering that photovoltaic power generation occurs during the day, while users generally have higher loads at night, configuring energy storage can better utilize photovoltaic power, improve the level of self-consumption, and reduce electricity costs. In addition, communication base stations, data centers, and other fields need to configure energy storage for backup power.

[0035] In some embodiments, please refer to Figure 1 , Figure 1 This is a schematic diagram of an energy storage system according to an embodiment of this application. Figure 1 The embodiments are illustrated using a shared energy storage scenario on the generation / distribution side as an example. The energy storage device in this application is not limited to the energy storage scenario on the generation / distribution side.

[0036] This application provides an energy storage system 4000. The energy storage system 4000 is used to supply power to electrical equipment. The energy storage system 4000 includes: a high-voltage cable 4100, a first power conversion device 4200, a second power conversion device 4300, and the energy storage device 1000 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4300 can be a wind power conversion device. Since the electricity generated by wind power conversion is volatile, random, and intermittent, the unstable electricity output by the wind power conversion device can be stored in the energy storage device 1000 through grid connection. The energy storage device 1000 is connected to the high-voltage cable 4100 and outputs smooth electricity to supply the power consumption side of the distribution network, achieving peak shaving and frequency regulation, and stable grid operation; or, the wind power conversion device initially... Finally, it connects to the high-voltage cable 4100. Under normal power generation conditions, the power output from the wind power conversion device is supplied to the power consumption side of the distribution network via the high-voltage cable. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in the energy storage device 1000, reducing wind and solar curtailment rates and improving the problem of new energy power generation consumption. Furthermore, when the power load is high, the grid issues an instruction to transmit the power stored in the energy storage device 1000, along with the high-voltage cable 4100, in a grid-connected mode to supply power to the power consumption side. This provides various services for grid operation, including peak shaving, frequency regulation, and backup, fully leveraging the grid's peak shaving function, promoting peak shaving and valley filling, and alleviating grid power supply pressure. It can be understood that the energy storage device 1000 in the energy storage system 4000 is used to supply power to electrical equipment.

[0037] In some embodiments on the distribution network side, the first power conversion device 4200 can be a photovoltaic power conversion device. The energy storage device 1000 is connected to the high-voltage cable 4100 and installed downstream of the high-voltage cable 4100 and between the user load. The power output of the photovoltaic power conversion device is stored in the energy storage device 1000, which can respond in a timely manner to act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line congestion when the high-voltage cable 4100 transmission line is blocked, and to delay the economic pressure caused by the expansion of the power grid / distribution capacity when the power grid is planned to be expanded.

[0038] Optionally, the first power conversion device 4200 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4300 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 4200 and the second power conversion device 4300 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0039] Optionally, the energy storage device 1000 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0040] Please see Figure 2 , Figure 3 and Figure 4 , Figure 2 for Figure 1 The diagram shown is a structural schematic of an energy storage device in an energy storage system. Figure 3 for Figure 2 The diagram shown is an exploded view of the energy storage device. Figure 4 for Figure 3 A simplified schematic diagram of the anode plate, cathode plate, and insulating film assembly of the battery cell in the energy storage device shown.

[0041] This application provides an energy storage device 1000. The energy storage device 1000 may include, but is not limited to, single-cell batteries, or battery modules, battery packs, battery clusters, power banks, energy storage cabinets / containers, and other battery integrated systems composed of single-cell batteries. Optionally, the single-cell battery can be a rechargeable battery, which refers to a battery cell that can be reactivated by charging after discharge and continue to be used. The single-cell battery can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit this. The actual application form of the energy storage device 1000 provided in this application embodiment can be, but is not limited to, the listed products, and can also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1000. This application embodiment only uses a square single-cell battery as an example for illustration. In some embodiments, when the energy storage device 1000 is a single battery cell, the energy storage device 1000 may also be a battery of other shapes besides a square battery, such as a cylindrical battery, a prismatic battery, etc.

[0042] For ease of description, the width direction of the energy storage device 1000 is defined as the X-axis, the length direction as the Y-axis, and the height direction as the Z-axis. The X-axis, Y-axis, and Z-axis are all perpendicular to each other.

[0043] The directional terms such as "upper," "lower," "bottom," "top," "right," and "left" mentioned in the embodiments of this application are based on the appendix to the specification. Figure 2 and Figure 3The description is based on the orientation shown. It 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 defined as the top or top of the energy storage device 1000, and the negative direction toward the Z-axis is defined as the bottom or bottom of the energy storage device 1000.

[0044] The energy storage device 1000 includes a housing 200, an end cap assembly 100, and a battery cell 300. The housing 200 has an opening 201 and a receiving cavity 202. The receiving cavity 202 communicates with the opening 201 and contains electrolyte. The battery cell 300 is housed within the receiving cavity 202 and can be immersed in the electrolyte. The end cap assembly 100 is mounted on one side of the battery cell 300 in the height direction (i.e., the Z-axis direction) and seals the opening 201 of the housing 200 to isolate the internal and external environments of the energy storage device 1000. In this embodiment, the housing 200 is a square aluminum shell.

[0045] like Figure 4 As shown, the battery cell 300 can be formed by alternatingly arranging an anode plate 301, a cathode plate 302, and an insulating film 303 located between the anode plate 301 and the cathode plate 302. It can be understood that an insulating film 303 is disposed between an adjacent anode plate 301 and a cathode plate 302. For example, the battery cell 300 has a stacked cell structure. Along the stacking direction of the anode plate 301, cathode plate 302 and insulating film 303, the projections of the cathode plate 302 and the anode plate 301 are completely within the projection of the insulating film 303, and the projection of the cathode plate 302 is completely within the projection of the anode plate 301. It can be understood that the area of ​​the insulating film 303 is larger than the area of ​​the anode plate 301 and the cathode plate 302, and the area of ​​the anode plate 301 is larger than the area of ​​the cathode plate 302, so as to avoid the cathode plate 302 being exposed between the insulating film 303 and the anode plate 301 and short-circuiting with the end cap assembly 100 after the anode plate 301, cathode plate 302 and insulating film 303 fall down together, affecting the safety of the energy storage device 1000.

[0046] Please refer to the following: Figure 5 , Figure 6 and Figure 7 , Figure 5 for Figure 3 The diagram shows a structural schematic of the end cap assembly of the energy storage device from another angle. Figure 6 for Figure 5 The diagram shown is an exploded view of the end cap assembly. Figure 7 for Figure 6 An exploded structural diagram of the end cap assembly from another angle. Wherein, Figure 5 , Figure 6 and Figure 7 The diagram illustrates the structure of a first embodiment of the second insulating element.

[0047] The end cap assembly 100 includes an end cap 10, a lower plastic 20, a bracket 40, an insulating component 50, an explosion-proof valve 60, a protective plate 70, a terminal post 80, an upper plastic 91, a pressure block 93, and a sealing ring 92. The explosion-proof valve 60 and the protective plate 70 are both mounted on the end cap 10. Along the thickness direction of the end cap assembly 100 (i.e., the Z-axis direction), the lower plastic 20 is stacked and connected to the end cap 10. The bracket 40 is housed within the lower plastic 20 and is snap-fitted to the lower plastic 20, pressing against the end cap 10. The bracket 40 presses against the battery cell 300 and separates the battery cell 300 from the end cap 10. The insulating component 50 is disposed corresponding to the bracket 40 and covers the side of the bracket 40 facing away from the end cap 10, thus insulating the battery cell 300 from the bracket 40. The pressure block 93 is mounted on the side of the upper plastic 91 facing away from the end cap 10. The electrode post 80 is sequentially inserted through the lower plastic 20, end cap 10, upper plastic 91, and pressure block 93, and is connected to the pressure block 93. The sealing ring 92 is fitted onto the electrode post 80 and clamped between the upper plastic 91, lower plastic 20, end cap 10, and electrode post 80 to seal the gap between the upper plastic 91, lower plastic 20, end cap 10, and electrode post 80.

[0048] Among them, such as Figure 6 and Figure 7 As shown, there are two of each of the following: terminal post 80, pressure block 93, upper plastic 91, and sealing ring 92. The two terminal posts 80 are located at opposite ends along the length of the end cap assembly 100, one serving as the positive terminal post and the other as the negative terminal post. One of the two pressure blocks 93 serves as the positive pressure block, and the other as the negative pressure block. One of the two upper plastic 91 is the positive upper plastic 91, and the other is the negative upper plastic 91. One of the two sealing rings 92 is the positive sealing ring, and the other is the negative sealing ring.

[0049] The positive electrode post is sequentially inserted through the lower plastic 20, the end cap 10, the upper positive plastic, and the positive electrode pressure block, and is connected to the positive electrode pressure block. The positive electrode sealing ring is fitted onto the positive electrode post and seals the gaps between the lower plastic 20, the end cap 10, the upper positive plastic, and the positive electrode post. The negative electrode post is sequentially inserted through the lower plastic 20, the end cap 10, the upper negative plastic, and the negative electrode pressure block, and is connected to the negative electrode pressure block. The positive electrode sealing ring is fitted onto the positive electrode post and seals the gaps between the lower plastic 20, the end cap 10, the upper negative plastic, and the negative electrode post.

[0050] In this embodiment, the bracket 40 includes two first brackets 40a and a second bracket 40b. Along the length of the end cap assembly 100, the two first brackets 40a are located at both ends of the end cap assembly 100, and the second bracket 40b is located between the two first brackets 40a and spaced apart from them. A pole post 80 is provided between the second bracket 40b and one of the first brackets 40a. Preferably, along the thickness direction of the end cap assembly 100, the second bracket 40b is disposed opposite to the explosion-proof valve 60.

[0051] In this embodiment, the insulating member 50 includes two first insulating members 51 and a second insulating member 52. Each first insulating member 51 is correspondingly disposed with a first bracket 40a and completely covers the side surface of the first bracket 40a facing away from the end cover 10, so as to insulate the battery cell 300 from the first bracket 40a and prevent the battery cell 300 and the first bracket 40a from short-circuiting. The second insulating member 52 is correspondingly disposed with a second bracket 40b and completely covers the side surface of the second bracket 40b facing away from the end cover 10, so as to insulate the battery cell 300 from the second bracket 40b and prevent the battery cell 300 from short-circuiting from the second bracket 40b. That is, along the thickness direction of the end cover assembly 100, the projection of the first bracket 40a is completely located within the projection of the first insulating member 51, and the projection of the second bracket 40b is completely located within the projection of the second insulating member 52.

[0052] The two first insulating components 51 and the second insulating component 52 can be, but are not limited to, polyimide tape (PI), polyethylene terephthalate tape (PET), polypropylene tape (PP), PI and PET composite tape, etc. In this embodiment, under the dual insulation effect of the insulating film 303 and the insulating component 50, the cathode plate 302 of the battery cell 300 is prevented from colliding with the first support 40a and the second support 40b, thus avoiding a short circuit and improving the safety of the energy storage device 1000.

[0053] In some embodiments, the number of first brackets 40a is not limited to two, and the number of second brackets 40b is not limited to one. They can also be designed as multiple according to actual product requirements. This application does not limit this. Correspondingly, the number of first insulating members 51 and second insulating members 52 is not limited.

[0054] In some embodiments, the surfaces of the first bracket 40a and the second bracket 40b are insulated, meaning that insulation between the battery cell 300 and the first bracket 40a and the second bracket 40b can be achieved without the need for an insulating member 50. This application does not impose any limitations on this.

[0055] Please refer to the following: Figure 6 , Figure 7 and Figure 8 , Figure 8 for Figure 7 The diagram shows the structural diagram of the end cap of the end cap assembly.

[0056] The end cap 10 includes a top surface 11 and a bottom surface 12. The top surface 11 and the bottom surface 12 are arranged facing away from each other along the thickness direction (i.e., the Z-axis direction) of the end cap 10. In this embodiment, the end cap 10 is a rectangular sheet of light aluminum.

[0057] The end cap 10 also includes a first electrode post hole 13. The first electrode post hole 13 extends through the top surface 11 and the bottom surface 12 of the end cap 10. The first electrode post hole 13 is used for the electrode post 80 to pass through. In this embodiment, there are two first electrode post holes 13. The two first electrode post holes 13 are respectively provided at opposite ends in the length direction (i.e., the Y-axis direction) of the end cap 10 and are spaced apart from each other. One first electrode post hole 13 is used for the positive electrode post to pass through, and the other first electrode post hole 13 is used for the negative electrode post to pass through.

[0058] The end cap 10 also includes an explosion-proof hole 14. The explosion-proof hole 14 extends through the top surface 11 and bottom surface 12 of the end cap 10. The explosion-proof hole 14 is used to accommodate the explosion-proof valve 60 and the protective plate 70, and to allow gas generated inside the energy storage device 1000 to escape. It can be understood that the explosion-proof hole 14, the explosion-proof valve 60, and the protective plate 70 can be understood as the explosion-proof structure of the end cap assembly 100. In this embodiment, along the length direction of the end cap 10, the explosion-proof hole 14 is located between the two first pole hole 13, and the explosion-proof hole 14 is spaced apart from the two first pole hole 13.

[0059] The end cap 10 also includes multiple limiting grooves 15. Each limiting groove 15 is recessed into the bottom surface 12 of the end cap 10 and recessed towards the top surface 11. The multiple limiting grooves 15 are spaced apart from each other, and are also spaced apart from the first pole post hole 13 and the explosion-proof hole 14. Each limiting groove 15 is used to engage with the lower plastic 20 for positioning.

[0060] The end cap 10 also includes a positioning groove 16. The positioning groove 16 is recessed into the bottom surface 12 of the end cap 10 and recessed towards the top surface 11. The positioning groove 16 is used to cooperate with the bracket 40 for positioning, thereby accelerating the assembly efficiency of the bracket 40 and the end cap 10. In this embodiment, as... Figure 8As shown, the depth of the positioning groove 16 is L1, and the thickness of the end cap 10 is H. The depth L1 of the positioning groove 16 is greater than or equal to 0.2mm to avoid the positioning groove 16 being too small and losing its limiting function for the bracket 40. Moreover, the ratio of the depth L1 of the positioning groove 16 to the thickness H of the end cap 10 is less than or equal to 0.5 to avoid the positioning groove 16 being too large, which would cause excessive extrusion of the material at the bottom of the positioning groove 16 during extrusion molding, resulting in work hardening and cracks, affecting the structural strength of the end cap 10.

[0061] In this embodiment, there are multiple positioning grooves 16, which are used to cooperate with and limit the positioning of the two first brackets 40a. To match the structure of the two first brackets 40a, the shapes of the multiple positioning grooves 16 can be different to prevent incorrect assembly. For ease of description, the multiple positioning grooves 16 are referred to as multiple first positioning grooves 16a, multiple second positioning grooves 16b, and multiple third positioning grooves 16c. Along the length of the end cap 10, the multiple first positioning grooves 16a are evenly distributed at opposite ends of the end cap 10, the multiple third positioning grooves 16c are evenly distributed at opposite ends of the end cap 10, and the multiple second positioning grooves 16b are evenly distributed at opposite ends of the end cap 10.

[0062] For example, there are eight first positioning grooves 16a, with four first positioning grooves 16a located at one end of the end cap 10 along its length, and the four first positioning grooves 16a are spaced apart along the width direction of the end cap 10. There are four third positioning grooves 16c, with two third positioning grooves 16c located at one end of the end cap 10 along its length, and the two third positioning grooves 16c are spaced apart along the width direction of the end cap 10. There are two second positioning grooves 16b, each of which is located at one end of the end cap 10 along its length. Moreover, taking one end of the end cap 10 along its length as an example, along the length direction of the end cap 10, the four first positioning grooves 16a, the second positioning grooves 16b, and the two third positioning grooves 16c are all located on the side of a first pole hole 13 away from the explosion-proof hole 14, and the second positioning grooves 16b are closer to the first pole hole 13 than the four first positioning grooves 16a and the two third positioning grooves 16c, and are spaced apart from the first pole hole 13. Along the width direction of the end cap 10, the four first positioning grooves 16a and the second positioning grooves 16b are closer to the center line of the width direction of the end cap 10 than the two third positioning grooves 16c.

[0063] In some embodiments, the number of the first positioning groove 16a, the third positioning groove 16c, and the second positioning groove 16b is not limited to the following: Figure 8 The number shown can also be set according to the actual structural design of the first bracket 40a. In some embodiments, the plurality of positioning slots 16 are also used to cooperate with the second bracket 40b for positioning. This application does not limit this.

[0064] Please refer to Figure 9 and Figure 10 , Figure 9 is a Figure 7 schematic structural view of a first embodiment of the lower plastic of the end cap assembly, Figure 10 is a Figure 9 schematic structural view of the lower plastic shown from another angle.

[0065] The lower plastic 20 comprises a first surface 21 and a second surface 22. The first surface 21 and the second surface 22 are disposed oppositely along the thickness direction of the lower plastic 20 (i.e., the Z-axis direction). In this embodiment, the lower plastic 20 is generally a rectangular plate and made of an insulating material, such as Polypropylene (PP).

[0066] The lower plastic 20 further comprises a second terminal post hole 23. The second terminal post hole 23 penetrates through the first surface 21 and the second surface 22 of the lower plastic 20. The second terminal post hole 23 is configured for a terminal post 80 to pass through. In this embodiment, the number of the second terminal post holes 23 is two. Along the length direction of the lower plastic 20, the two second terminal post holes 23 are respectively located at opposite ends of the lower plastic 20 and spaced apart from each other. One of the second terminal post holes 23 is configured for the positive terminal post to pass through, and the other second terminal post hole 23 is configured for the negative terminal post to pass through.

[0067] The lower plastic 20 further comprises a first boss 24. The first boss 24 is disposed on the second surface 22 and protrudes from the second surface 22 in a direction away from the first surface 21. The first boss 24 comprises a boss surface 241, a first boss side surface 242 and a second boss side surface 243. The boss surface 241 faces the same direction as the second surface 22, the first boss side surface 242 and the second boss side surface 243 are disposed oppositely along the width direction of the first boss 24 (i.e., the Y-axis direction). Both the first boss side surface 242 and the second boss side surface 243 are connected to the boss surface 241, and the first boss side surface 242 is farther away from the middle of the lower plastic 20 than the second boss side surface 243. The first boss 24 is configured to press against a cell 300, and the boss surface 241 faces the cell 300. Along the length direction of the lower plastic 20 (i.e., the Y-axis direction), the first boss 24 is located at an end of the lower plastic 20, and the first boss 24 is configured to correspond to a first bracket 40a. In this embodiment, the number of the first bosses 24 is two, and along the Y-axis direction, the two first bosses 24 are respectively located at opposite ends of the lower plastic 20. The first boss 24 is generally a convex-shaped boss, the boss surface 241 is generally a convex-shaped surface, the first boss side surface 242 is generally a flat surface, and the second boss side surface 243 is generally an uneven surface protruding toward the middle of the lower plastic 20.

[0068] The lower plastic 20 also includes a first through groove 25. The opening of the first through groove 25 is located on the first surface 21, and the first through groove 25 is recessed from the first surface 21 toward the boss surface 241 of the first boss 24, and the first through groove 25 penetrates a portion of the boss surface 241 of the first boss 24. That is, the first through groove 25 is located at the end of the lower plastic 20 in the length direction and is correspondingly provided with the first boss 24.

[0069] The first through groove 25 has a first groove sidewall 251, a second groove sidewall 252, two groove end walls 253, and a groove bottom wall 254. The first groove sidewall 251 and the second groove sidewall 252 are arranged opposite to each other and spaced apart along the length direction of the lower plastic 20, and the second groove sidewall 252 is closer to the second pole post hole 23 than the first groove sidewall 251. The two groove end walls 253 are arranged opposite to each other and spaced apart along the width direction of the lower plastic 20, and both groove end walls 253 are connected to the first groove sidewall 251 and the second groove sidewall 252. The groove bottom wall 254 protrudes from the first groove sidewall 251 and extends toward the second groove sidewall 252, and the groove bottom wall 254 is spaced apart from the second groove sidewall 252. The two ends of the groove bottom wall 254 in the length direction are respectively connected to the two groove end walls 253. The groove bottom wall 254 and the groove opening of the first through groove 25 are arranged opposite to each other and spaced apart along the thickness direction of the lower plastic 20.

[0070] A side plate 255 protrudes from the bottom wall 254 of the tank, and the side plate 255 is set at an angle to the bottom wall 254. The side plate 255 is connected to the first tank side wall 251 and is set at an angle to the first tank side wall 251. The number of side plates 255 can be one or more. The side plates 255 are spaced apart from the two tank end walls 253, and when there are multiple side plates 255, the multiple side plates 255 are spaced apart along the width direction of the lower plastic 20. In this embodiment, the number of side plates 255 is four.

[0071] The bottom wall 254 of the tank includes two first sub-walls 254a and a second sub-wall 254b. The two first sub-walls 254a are spaced apart along the width direction of the lower plastic 20 and are respectively connected to the two end walls 253 of the tank. The second sub-wall 254b is located between the two first sub-walls 254a and is spaced apart from them. Each first sub-wall 254a and the second sub-wall 254b forms a first clearance notch 28a, which can also be understood as the first clearance notch 28a penetrating the bottom wall 254 and exposing the first side wall 251 of the tank. The first clearance notch 28a is used to cooperate with the first bracket 40a for clearance.

[0072] Two side plates 255 are respectively connected to the opposite sides of the second sub-wall 254b in the width direction of the lower plastic 20, and two other side plates 255 are respectively connected to the two first sub-walls 254a. The first sub-wall 254a is also provided with a buckle 256. The buckle 256 and the side plates 255 of the first sub-wall 254a are spaced apart in the width direction of the lower plastic 20, and the buckle 256 is closer to the groove end wall 253 to which the first sub-wall 254a is connected than the side plates 255. The buckle 256 and the groove end wall 253 are opposite to and spaced apart in the X-axis direction. The buckle 256 is provided on the edge of the first sub-wall 254a near the second groove side wall 252 for engaging with the first bracket 40a.

[0073] The lower plastic 20 also includes a plurality of vent holes 26. The plurality of vent holes 26 extend through both sides of the first sub-wall 254a in the thickness direction and both sides of the second sub-wall 254b in the thickness direction. The plurality of vent holes 26 are spaced apart along the width direction of the lower plastic 20. The plurality of vent holes 26 communicate with the first through groove 25 and the outside of the lower plastic 20, and are used to allow gas rising from the side of the power core 300 to pass through, so that the gas can smoothly enter the first through groove 25.

[0074] The lower plastic 20 also includes an air guide groove 27. The air guide groove 27 is recessed into the boss surface 241 of the first boss 24 (which can also be understood as the wall surface of the first sub-wall 254a and the second sub-wall 254b facing away from the opening of the first through groove 25). Along the thickness direction of the lower plastic 20, the projection of the air guide groove 27 partially coincides with the projection of the plurality of air guide holes 26, and the air guide groove 27 communicates with the plurality of air guide holes 26 and the outside of the lower plastic 20. The air guide groove 27 penetrates a portion of the wall surface of the first groove sidewall 251 facing the second groove sidewall 252 and communicates with the first through groove 25. It can be understood that the air guide groove 27 extends along the width direction of the lower plastic 20. A portion of the venting groove 27 is indirectly connected to the first through groove 25 through multiple venting holes 26, while another portion of the venting groove 27 is directly connected to the first through groove 25. This allows the gas rising from the side of the battery cell 300 to not only enter the first through groove 25 through multiple venting holes 26, but also to enter the first through groove 25 through multiple venting holes 26 from the venting groove 27. This increases the channel area for gas to enter the first through groove 25, effectively preventing the insulating film 303 of the battery cell 300 from pressing against the first protrusion 24 and blocking multiple venting holes 26 when the lower plastic 20 comes into contact with the battery cell 300. This would prevent the gas rising from the side of the battery cell 300 from entering the first through groove 25 through multiple venting holes 26, leading to increased air pressure and potentially causing severe deformation of the battery cell 300 and cracking of the casing 200.

[0075] The lower plastic 20 also includes a second clearance notch 28b and a vent 29. The second clearance notch 28b is recessed into the second groove sidewall 252 and recessed into the middle of the lower plastic 20 from the second groove sidewall 252. The second clearance notch 28b is used to cooperate with and avoid the first bracket 40a. The vent 29 penetrates both sides of the second groove sidewall 252 in the thickness direction. The vent 29 connects the first through groove 25 and the outside of the lower plastic 20, and is used to allow gas in the first through groove 25 to pass through. The number of vents 29 can be one or more. In this embodiment, the number of vents 29 is two. The two vents 29 are located at both ends of the second groove sidewall 252 in the X-axis direction and are spaced apart. Along the length direction of the lower plastic 20, the second clearance notch 28b is located between the two vents 29 and is spaced apart from the two vents 29, and the second clearance notch 28b is completely offset from the first clearance notch 28a.

[0076] The lower plastic 20 also includes a return channel 30. The return channel 30 is recessed into the first surface 21 of the lower plastic 20 and recessed into the boss surface 241 of the first boss 24, extending through the second boss side 243 of the first boss 24. It can be understood that the return channel 30 has two openings, one on the first surface 21 and the other on the second boss side 243 of the first boss 24. The return channel 30 is used to allow the electrolyte on the first surface 21 of the lower plastic 20 to flow back to the battery cell 300, ensuring the continuous and stable operation of the energy storage device 1000. Furthermore, the inclusion of the return channel 30 in the lower plastic 20 reduces the material usage of the lower plastic 20, achieving a lighter end cap assembly 100. The number of return channels 30 can be one or more. In this embodiment, there are two return channels 30. Two return channels 30 are spaced apart along the width of the lower plastic 20, and both return channels 30 are located between the two vent holes 29 and the second clearance notch 28b, and are spaced apart from the two vent holes 29 and the second clearance notch 28b.

[0077] The lower plastic 20 also includes a first reinforcing rib 31. The first reinforcing rib 31 is disposed within the first through groove 25, spanning the width direction of the first through groove 25 (i.e., the length direction of the lower plastic 20), and its two ends in the length direction are respectively connected to the side plate 255 and the second groove side wall 252. The first reinforcing rib 31 is used to strengthen the overall structural strength of the lower plastic 20. The number of first reinforcing ribs 31 can be one or more. The first reinforcing ribs 31 and the two groove end walls 253 are spaced apart along the width direction of the lower plastic 20, and when there are multiple first reinforcing ribs 31, they are spaced apart along the width direction of the lower plastic 20. In this embodiment, there are two first reinforcing ribs 31, each connected to one side plate 255 and the second groove side wall 252 of the second sub-wall 254b.

[0078] In this embodiment, along the thickness direction of the lower plastic 20, the first reinforcing rib 31 is lower than the first boss 24, that is, there is a gap between the first reinforcing rib 31 and the boss surface 241 of the first boss 24, so as to avoid the first reinforcing rib 31 affecting the assembly of the first bracket 40a. In some embodiments, the first reinforcing rib 31 can be directly connected to the bottom wall 254 of the groove and the side wall 252 of the groove. This application does not limit this.

[0079] In this embodiment, there are two first through slots 25, and the two first through slots 25 have approximately the same structure. Along the Y-axis, the two first through slots 25 are located at opposite ends of the lower plastic 20, and each first through slot 25 is correspondingly provided with a first boss 24 and is used to accommodate a first bracket 40a.

[0080] The lower plastic 20 also includes a second through groove 32. The second through groove 32 extends through both sides of the lower plastic 20 in the thickness direction and is located between and spaced apart from the two first through grooves 25 along the length direction of the lower plastic 20. The second through groove 32 is used to accommodate the second support 40b. The second through groove 32 includes two end walls 321, which are opposite to and spaced apart along the width direction of the lower plastic 20.

[0081] The lower plastic 20 also includes a plurality of second protrusions 33. Each of the second protrusions 33 protrudes from the second surface 22 of the lower plastic 20, and is respectively disposed on opposite sides of the second through groove 32 along its length. The second protrusions 33 are spaced apart along the width of the lower plastic 20 to allow gas rising from the side of the battery cell 300 to flow into the second through groove 32 through the gaps between the second protrusions 33. The second protrusions 33 serve to separate the second support 40b housed within the second through groove 32 from the tabs extended from the battery cell 300, preventing the tabs extended from the battery cell 300 from short-circuiting with the second support 40b during winding or stacking of electrode sheets. In this embodiment, there are eight second protrusions 33, and every four second protrusions 33 are disposed on the same side of the second through groove 32 along its length.

[0082] Each second boss 33 includes a boss surface 331. The boss surface 331 faces the same direction as the second surface 22 of the lower plastic 20. The lower plastic 20 also includes a plurality of grooves 35. Each groove 35 is recessed into the first surface 21 of the lower plastic 20 and is recessed toward the boss surface 331 of a second boss 33. Each groove 35 penetrates the side of the second boss 33 facing the second through groove 32 and communicates with the second through groove 32. That is, each groove 35 is correspondingly provided to a second boss 33, and the plurality of grooves 35 are spaced apart along the width direction of the lower plastic 20, which improves the manufacturability of the lower plastic 20. At the same time, it also reduces the material used in the lower plastic 20, avoids the lower plastic 20 being too thick, which would cause severe shrinkage during injection molding, and avoids unevenness on the surface of the lower plastic 20. Each second groove 35b has two openings, one on the first surface 21 and the other on the side of the second boss 33 facing the second through groove 32.

[0083] Each groove 35 includes two third groove sidewalls 351, a fourth groove sidewall 352, and a bottom wall 353. The two third groove sidewalls 351 are arranged opposite to each other and spaced apart along the width direction of the lower plastic 20. The fourth groove sidewall 352 and the bottom wall 353 are both connected to the two third groove sidewalls 351. The bottom wall 353 faces the same direction as the first surface 21 of the lower plastic 20. The fourth groove sidewall 352 faces the second through groove 32.

[0084] In this embodiment, there are eight grooves 35. For ease of description, the eight grooves 35 are divided into four first grooves 35a and four second grooves 35b. The four first grooves 35a are located on one side of the second through groove 32 along the length direction of the lower plastic 20, and the four second grooves 35b are located on the other side of the second through groove 32 along the length direction of the lower plastic 20. Each first groove 35a and one second groove 35b are positioned opposite each other and spaced apart along the length direction of the lower plastic 20. A third groove sidewall 351 of the first groove 35a and a third groove sidewall 351 of the second groove 35b, located near the same end in the width direction of the lower plastic 20, are connected together to an end wall 321. The other third groove sidewall 351 of the first groove 35a and the other third groove sidewall 351 of the second groove 35b are positioned opposite each other and spaced apart. Both the bottom wall 353 of the first groove 35a and the bottom wall 353 of the second groove 35b, located near the same end in the width direction of the lower plastic 20, are provided with protruding hooks 36, and the hooks 36 are adjacent to and spaced apart from the end wall 321. The hooks 36 are located on the edge of the bottom wall 353 near the second through groove 32 for engaging with the second bracket 40b.

[0085] The lower plastic 20 also includes a second reinforcing rib 37. The second reinforcing rib 37 is located within the second through groove 32, and is spaced apart from the two end walls 321 along the width direction of the lower plastic 20. The second reinforcing rib 37 spans the width direction of the second through groove 32 (i.e., the length direction of the lower plastic 20), and its two ends along the length direction are respectively connected to two third groove sidewalls 351 spaced apart from the first groove 35a and the second groove 35b. The second reinforcing rib 37 is used to strengthen the overall structural strength of the lower plastic 20. The number of second reinforcing ribs 37 can be one or more. In this embodiment, there are two second reinforcing ribs 37, spaced apart along the width direction of the lower plastic 20, and each second reinforcing rib 37 is adjacent to one end wall 321. That is, each second reinforcing rib 37 is connected to the first groove 35a and the second groove 35b near one end of the lower plastic 20 in the width direction, and connects to the two third groove sidewalls 351 spaced apart from the first groove 35a and the second groove 35b.

[0086] In this embodiment, along the thickness direction of the lower plastic 20, the second reinforcing rib 37 and the boss surface 331 of the second boss 33 are spaced apart to avoid the second reinforcing rib 37 affecting the assembly of the second bracket 40b.

[0087] The lower plastic 20 also includes a plurality of limiting posts 38. The plurality of limiting posts 38 are all protruding from the first surface 21 of the lower plastic 20 and are spaced apart from each other. Each limiting post 38 is used to be received in a limiting groove 15 of the end cap 10 to achieve limiting and fixing of the lower plastic 20 and the end cap 10.

[0088] Please refer to the following: Figure 11 and Figure 12 , Figure 11 for Figure 7 The diagram shows the structure of the two first supports and the second support of the end cap assembly. Figure 12 for Figure 11 The diagram shows the structure of the two first supports and the second support from another angle. Figure 11 and Figure 12 The dashed line in the middle represents the boundary between the first support leg a3 and the main body of the support a1.

[0089] In this embodiment, the two first supports 40a and the second support 40b are typically made of the same material as the end cap 10, both being metal. This gives the two first supports 40a and the second support 40b a higher melting point and structural strength compared to the lower plastic 20, improving manufacturability. The structures of the two first supports 40a are largely the same; the following description will use one first support 40a as an example. In some embodiments, the two first supports 40a and the second support 40b may also be made of ceramic material; this application does not impose any limitations on this.

[0090] The first bracket 40a includes a bracket body a1, two snap-fit ​​bodies a2, a first leg a3, and a second leg a4. Along the length direction (X-axis direction) of the first bracket 40a, the two snap-fit ​​bodies a2 are bent and connected to opposite ends of the bracket body a1, protruding from the thickness direction of the bracket body a1. Each snap-fit ​​body a2 is set at an angle to the bracket body a1 (the angle is exemplarily 90°). Along the width direction (Y-axis direction) of the first bracket 40a, the first leg a3 and the second leg a4 are connected to opposite sides of the bracket body a1, both protruding from the thickness direction of the bracket body a1. Along the length direction of the first bracket 40a, the first leg a3 and the second leg a4 are located between the two snap-fit ​​bodies a2, and are spaced apart from the two snap-fit ​​bodies a2. The bracket body a1 is used to press against the battery cell 300. Two snap-fit ​​bodies a2 are respectively used to engage with the two third positioning grooves 16c of the end cap 10 for limiting their position, and each snap-fit ​​body a2 is used to engage with a snap fastener 256 of the lower plastic 20. The first support leg a3 is used to engage with the first positioning groove 16a of the end cap 10 for limiting its position. The second support leg a4 is used to engage with the second positioning groove 16b of the end cap 10 for limiting its position. The two snap-fit ​​bodies a2, the first support leg a3, and the second support leg a4 are all used to support the end cap 10.

[0091] The connections between the components of the first bracket 40a can be described as follows: two components are connected by a third component, such as through a glue connection; two components are directly connected, such as through a snap-fit ​​connection; or two components are connected by integral molding. In this embodiment, all connections between the components of the first bracket 40a are described as integral connections. That is, the first bracket 40a is an integrally molded structure, and the bracket body a1, the two snap-fit ​​bodies a2, the first leg a3, and the second leg a4 are all integrally molded through a bending process to form the first bracket 40a as a whole.

[0092] The support body a1 includes a first upper surface a11, a first lower surface a12, a first side surface a13, and a second side surface a14. The first upper surface a11 and the first lower surface a12 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the support body a1. The first side surface a13 and the second side surface a14 are arranged opposite to each other along the width direction (i.e., the Y-axis direction) of the support body a1. Both the first side surface a13 and the second side surface a14 are connected to the first upper surface a11 and the first lower surface a12. In this embodiment, the support body a1 is generally a long rectangular plate.

[0093] In this embodiment, the two snap-fit ​​bodies a2 have roughly the same structure. The following description will use one snap-fit ​​body a2 as an example.

[0094] The latching body a2 includes a first latching surface a21 and a second latching surface a22. The first latching surface a21 and the second latching surface a22 are arranged facing away from each other along the width direction (i.e., the Y-axis direction) of the latching body a2. The first latching surface a21 has the same orientation as the first side surface a13 and is connected to the first side surface a13. The second latching surface a22 has the same orientation as the second side surface a14 and is connected to the second side surface a14.

[0095] The snap-fit ​​body a2 also includes a first snap-fit ​​groove a23. The first snap-fit ​​groove a23 is recessed in the first snap-fit ​​surface a21 of the snap-fit ​​body a2 and is recessed towards the second snap-fit ​​surface a22, and the first snap-fit ​​groove a23 penetrates both surfaces of the snap-fit ​​body a2 in the thickness direction (i.e., the X-axis direction). The first snap-fit ​​groove a23 is used to snap and fix with the buckle 256 of the lower plastic 20.

[0096] In this embodiment, the structures of the first leg a3 and the second leg a4 are different. The number of the first leg a3 and the second leg a4 can be one or more. For example, the first leg a3 is approximately U-shaped, and there are two first legs a3, spaced apart along the X-axis. The second leg a4 is approximately a rectangular upright plate, and there is one second leg a4. Along the length of the first support 40a, the second leg a4 is offset from the two first legs a3, and the second leg a4 is located between the two first legs a3. That is, along the width of the first support 40a, the projection of the second leg a4 does not coincide with the projection of the two first supports 40a.

[0097] The first support leg a3 includes a support body a31 and two support bodies a32. The support body a31 protrudes from the first side a13 of the support body a1 and extends along the width direction of the support body a1. The two support bodies a32 are respectively connected to opposite sides of the support body a31 in the length direction of the first support 40a, and the two support bodies a32 are opposite to each other and spaced apart. Both support bodies a32 protrude from the thickness direction of the support body a31 and extend along the thickness direction (i.e., the Z-axis direction) of the support body a31. Both support bodies a32 are set at an angle to the support body a31 (the included angle is exemplarily 90°). Moreover, both support bodies a32 are set at an angle to the support body 40 and are opposite to the first side a13 of the support body in the width direction of the first support 40a.

[0098] The support body a31 includes a first surface a33, a second surface a34, and two end surfaces a35. The first surface a33 and the second surface a34 are arranged facing away from each other along the thickness direction (i.e., the Z-axis direction) of the support body a31. The two end surfaces a35 are arranged facing away from each other along the length direction (i.e., the X-axis direction) of the support body a31. Both end surfaces a35 are connected to the first surface a33 and the second surface a34. The first surface a33 is connected to the first upper surface a11 of the support body a1 and faces the same direction as the first upper surface a11. The second surface a34 is connected to the first lower surface a12 of the support body a1 and faces the same direction as the first lower surface a12. The extending directions of both end surfaces a35 intersect with the first side surface a13, specifically, they can be perpendicular. Two support bodies a32 are respectively connected to the two end surfaces a35 and both protrude from the first surface a33 of the support body a31. The length direction of the connection (connection boundary) between the two support bodies a32 and the foot body a31 is perpendicular to the first side a13. Both support bodies a32 are set at an angle to the foot body a31 (the angle is exemplarily 90°). The foot body a31 is used to abut against the battery cell 300. Each support body a32 is used to engage with a first positioning groove 16a of the end cover 10 for positioning, and the support body a32 is used to support the end cover 10.

[0099] In this embodiment, the first support a3 can be formed into two support bodies a32 and a support body a31 by bending. Both support bodies a32 are rectangular vertical plates, and the two opposing surfaces of the two support bodies a32 along the length direction of the first bracket 40a are parallel to the length direction of the end cap assembly 100. That is, both support bodies a32 are continuous vertical plates along the length direction of the end cap assembly 100. When the energy storage device 1000 experiences thermal runaway and generates a large amount of gas inside, the battery cell 300 and the large amount of gas compress the first bracket 40a, making the first bracket 40a easily bend towards the end cap 10. The first support a3 provides continuous support for the end cap 10 along the length direction of the end cap 10, dispersing the bending moment of the first bracket 40a in the length direction of the end cap 10, improving the bending strength of the first bracket 40a in the width direction, reducing the overall deformation of the first bracket 40a along the length direction of the end cap 10, and thus avoiding the reduction of the airflow channel Q1 formed between the first bracket 40a and the end cap 10.

[0100] The second leg a4 protrudes from the second side a14 of the support body a1, and also protrudes from the first upper surface a11 of the support body a1. Along the thickness direction of the first support 40a, the second leg a4 extends away from the support body a1. The second leg a4 and the support body a1 are arranged at an angle (the angle is exemplarily 90°).

[0101] In this embodiment, the second support leg a4 is bent relative to the main body a1 of the support through a bending process. The thickness direction of the second support leg a4 is parallel to the width direction of the first support 40a, that is, parallel to the length direction of the end cap assembly 100. It can be understood that the second support leg a4 is a continuous vertical plate perpendicular to the length direction of the end cap assembly 100. When the energy storage device 1000 experiences thermal runaway and generates a large amount of gas inside, the battery cell 300 and the large amount of gas compress the first support 40a, making the first support 40a easy to bend towards the end cap 10. The second support leg a4 provides continuous support for the end cap 10 along the width direction of the end cap 10, disperses the bending moment of the first support 40a in the width direction of the end cap 10, improves the bending strength of the first support 40a in the length direction, and reduces the overall deformation of the first support 40a along the width direction of the end cap 10.

[0102] The second bracket 40b includes a bracket body b1, two snap-fit ​​sections b2, and multiple third legs b3. Along the length direction (X-axis) of the second bracket 40b, the two snap-fit ​​sections b2 are bent and connected to opposite ends of the bracket body b1, protruding from the thickness direction (Z-axis) of the bracket body b1. Each snap-fit ​​section b2 is angled to the bracket body b1 (the angle is exemplarily 90°). Along the width direction (Y-axis) of the second bracket 40b, multiple third legs b3 are connected to opposite sides of the bracket body b1. Each third leg b3 protrudes from the thickness direction of the bracket body b1. Along the length direction of the second bracket 40b, the multiple third legs b3 are spaced apart, and each third leg b3 is located between and spaced apart from the two snap-fit ​​sections b2. The bracket body b1 is used to press against the battery cell 300. Each snap-fit ​​segment b2 is used to engage with a hook 36 of the lower plastic 20, and both snap-fit ​​segments b2 and multiple third legs b3 are used to support the end cap 10.

[0103] The connections between the components of the second bracket 40b can be represented as follows: two components are connected by a third component, such as through a glue connection; two components are directly connected, such as through a snap-fit ​​connection; or two components are connected by integral molding. In this embodiment, all connections between the components of the second bracket 40b are represented as integral connections. That is, the second bracket 40b is an integrally molded structure, and the bracket body b1, the two snap-fit ​​sections b2, and the multiple third legs b3 are all integrally molded through a bending process to form the second bracket 40b as a whole.

[0104] The support body b1 includes a second upper surface b11, a second lower surface b12, and two third side surfaces b13. The second upper surface b11 and the second lower surface b12 are arranged opposite to each other along the thickness direction (i.e., the Z-axis direction) of the support body b1. The two third side surfaces b13 are arranged opposite to each other along the width direction (i.e., the Y-axis direction) of the support body b1. Both third side surfaces b13 are connected to the second upper surface b11 and the second lower surface b12. In this embodiment, the support body b1 is generally a long rectangular plate.

[0105] The support body b1 also includes multiple vent holes b4. These vent holes b4 extend through the second upper surface b11 and the second lower surface b12 of the support body b1. The multiple vent holes b4 are used to allow gas to pass through.

[0106] In this embodiment, the structures of the two snap-fit ​​segments b2 are roughly the same. The following description will use one snap-fit ​​segment b2 as an example.

[0107] The snap-fit ​​segment b2 includes two third snap-fit ​​surfaces b21. The two third snap-fit ​​surfaces b21 are arranged facing away from each other along the width direction (i.e., the Y-axis direction) of the snap-fit ​​segment b2. Each third snap-fit ​​surface b21 has the same orientation as a third side surface b13 and is connected to the third side surface b13.

[0108] The snap-fit ​​segment b2 also includes a second snap-fit ​​groove b22. The second snap-fit ​​groove b22 is recessed into one third snap-fit ​​surface b21 of the snap-fit ​​segment b2 and recessed towards the other third snap-fit ​​surface b21, extending through both surfaces of the snap-fit ​​segment b2 in the thickness direction (i.e., the X-axis direction). The second snap-fit ​​groove b22 is used for snap-fit ​​fixing with the hook 36 of the lower plastic 20. In this embodiment, there are two second snap-fit ​​grooves b22, located on opposite sides of the snap-fit ​​segment b2 in the Y-axis direction.

[0109] The third leg b3 protrudes from the third side b13 of the bracket body b1, and also protrudes from the second upper surface b11 of the bracket body b1. Along the thickness direction of the second bracket 40b, the third leg b3 extends away from the bracket body b1. The third leg b3 and the bracket body b1 are set at an angle (the included angle is exemplarily 90°). In this embodiment, the third leg b3 is bent relative to the bracket body b1 by a bending process. The thickness direction of the third leg b3 is parallel to the width direction (i.e., the Y-axis direction) of the second bracket 40b, that is, parallel to the length direction of the end cap assembly 100. The third leg b3 is a rectangular upright plate perpendicular to the length direction of the end cap assembly 100.

[0110] The number of third legs b3 is at least two, and the number of third legs b3 on each side of the support body b1 in the width direction is the same, so as to ensure that the force on the second support 40b can be evenly distributed on each third leg b3 and avoid deformation of the second support 40b. In this embodiment, the number of third legs b3 is four, and every two third legs b3 are located on one side of the support body b1 in the width direction. The four third legs b3 are arranged opposite each other and spaced apart along the length direction of the support body b1. In the event of thermal runaway of the energy storage device 1000, even if the lower plastic 20 fails and the battery cell 300 and a large amount of gas compress the second support 40b, the four third legs b3 can still ensure that the second support 40b is well supported between the end cap 10 and the battery cell 300, and will not cause the second support 40b to deform towards the end cap 10. This avoids reducing the ventilation channel Q2 formed between the second support 40b and the end cap 10, and at the same time, it also prevents the battery cell 300 from shifting, ensuring good ventilation performance of the end cap assembly 100 and improving the safety of the energy storage device 1000.

[0111] Please refer to the following: Figure 13 , Figure 14 and Figure 15 , Figure 13 for Figure 7 The diagram shows the assembly structure of the lower plastic part of the end cap assembly with the two first brackets and the second bracket. Figure 14 for Figure 13 The diagram shown is a structural schematic of the assembly structure from another angle. Figure 15 for Figure 13 The diagram shows a cross-sectional view of the assembly structure along AA.

[0112] In this embodiment, two first brackets 40a are mounted on the lower plastic 20. Each first bracket 40a is received within a first through groove 25 of the lower plastic 20.

[0113] Specifically, the support body a1 of the first support 40a is located between the bottom wall 254 and the second side wall 252 of the groove, and between the two end walls 253 of the groove. The first side a13 of the support body a1 faces the bottom wall 254 of the groove and is spaced apart from the bottom wall 254. The second side a14 of the support body a1 faces the second side wall 252 of the groove and is spaced apart from the second side wall 252.

[0114] In this embodiment, the support body a1 is located on the side of the two first reinforcing ribs 31 near the boss surface 241 of the first boss 24, and the first upper surface a11 of the support body a1 faces the two first reinforcing ribs 31. There is a certain distance between the two first reinforcing ribs 31 and the boss surface 241 of the first boss 24, ensuring that the support body a1 is a continuous and complete plate. In the event of thermal runaway of the energy storage device 1000, even if the lower plastic 20 melts and fails, the support body a1 can continuously press against the battery cell 300 and prevent the battery cell 300 from moving towards the end cover 10, thereby reducing the exhaust channel between the battery cell 300 and the end cover 10.

[0115] In this embodiment, along the thickness direction of the lower plastic 20, the boss surface 241 of the first boss 24 protrudes from the first lower surface a12 of the support body a1. That is, there is a height difference S between the first lower surface a12 of the support body a1 and the boss surface 241 of the first boss 24. The height difference S is greater than or equal to 0.1 mm. When the energy storage device 1000 is inverted, the battery cell 300 impacts the lower plastic 20, which has a buffer function, instead of directly impacting the rigid first support 40a. This not only avoids damage to the battery cell 300 from the impact of the first support 40a, but also avoids the support body a1 protruding from the first boss 24, thus preventing the lower plastic 20 from losing its function of pressing against the battery cell 300. Moreover, the height difference S is less than or equal to one-third of the overall height of the first support 40a. When the energy storage device 1000 experiences thermal runaway and the lower plastic 20 melts and fails, the battery cell 300 abuts against the support body a1 of the first support 40a. During the process of the battery cell 300 changing from abutting against the lower plastic 20 to abutting against the first support 40a, the change in the height difference S is not significant. That is, the height change of the exhaust channel between the battery cell 300 and the end cover 10 in the Z-axis direction is not significant, and it can still effectively exhaust air, ensuring the safety of the energy storage device 1000.

[0116] Each snap-fit ​​body a2 of the first bracket 40a is located between a first sub-wall 254a and a second groove sidewall 252, and the first snap-fit ​​surface a21 of the snap-fit ​​body a2 faces the first sub-wall 254a, the second snap-fit ​​surface a22 faces the second groove sidewall 252, and the first snap-fit ​​groove a23 of the snap-fit ​​body a2 engages with the buckle 256 on the first sub-wall 254a to fix the first bracket 40a to the lower plastic 20.

[0117] Each first leg a3 of the first bracket 40a is housed within a first clearance notch 28a, located between the second sub-wall 254b and the first sub-wall 254a. The two supports a32 of the first leg a3 are spaced apart from the two side plates 255 opposite to the first sub-wall 254a and the second sub-wall 254b, respectively. The side plates 255 provide guidance for the installation of the first bracket 40a.

[0118] The second leg a4 of the first support 40a is housed in the second clearance notch 28b and is positioned opposite and spaced apart from the second sub-wall 254b, with the second leg a4 located between the two second reinforcing ribs 37.

[0119] In this embodiment, along a direction perpendicular to the Z-axis, the edge of the first bracket 40a has an assembly gap D between it and the first groove sidewall 251, the second groove sidewall 252, and the two groove end walls 253 of the second through groove 32. The assembly gap D is greater than or equal to 0.1mm to prevent the first bracket 40a from scraping against the lower plastic 20 and generating plastic debris when it is assembled with the lower plastic 20, which would affect the safety of the energy storage device 1000. Specifically, the two surfaces of the two snap-fit ​​bodies a2, which are arranged opposite to each other along the X-axis, have assembly gaps D between them and the two groove end walls 253, between the first support leg a3 and the first groove sidewall 251, between the first sidewall a13 of the bracket body a1 and the groove bottom wall 254, between the second sidewall a14 of the bracket body a1 and the second groove sidewall 252, and between the second support leg a4 and the second groove sidewall 252. The assembly gap D between the first side a13 of the support body a1 and the first groove sidewall 251 is large enough to allow gas to enter the first through groove 25 directly from the gas guide groove 27 without being blocked by the first support 40a.

[0120] The second bracket 40b is mounted on the lower plastic 20 and housed within the second through groove 32 of the lower plastic 20. The bracket body b1 of the second bracket 40b is located between the two end walls 321 of the second through groove 32 and on the side of the two second reinforcing ribs 37 near the boss surface 331 of the second boss 33. The second upper surface b11 of the bracket body b1 faces the two second reinforcing ribs 37. There is a certain distance between the two second reinforcing ribs 37 and the boss surface 331 of the second boss 33, ensuring that the bracket body b1 is a continuous plate. In the event of thermal runaway of the energy storage device 1000, even if the lower plastic 20 melts and fails, the bracket body b1 can continuously press against the battery cell 300 and prevent the battery cell 300 from moving towards the end cover 10, thereby reducing the exhaust channel between the battery cell 300 and the end cover 10.

[0121] In this embodiment, along the thickness direction of the lower plastic 20, the protrusion surface 331 of the second protrusion 33 protrudes from the second lower surface b12 of the bracket body b1. That is, there is a height difference S between the second lower surface b12 of the bracket body b1 and the protrusion surface 331 of the second protrusion 33. The height difference S is greater than or equal to 0.1 mm. When the energy storage device 1000 is inverted, the battery cell 300 impacts the lower plastic 20, which has a buffer function, instead of directly impacting the rigid second bracket 40b. This not only avoids damage to the battery cell 300 from the impact of the second bracket 40b, but also avoids the bracket body b1 protruding from the second protrusion 33, thus preventing the lower plastic 20 from losing its function of pressing against the battery cell 300. Moreover, the height difference S is less than or equal to one-third of the overall height of the second support 40b. When the energy storage device 1000 experiences thermal runaway and the lower plastic 20 melts and fails, the battery cell 300 abuts against the support body b1 of the second support 40b. During the process of the battery cell 300 changing from abutting against the lower plastic 20 to abutting against the second support 40b, the change in the height difference S is not significant. That is, the height change of the exhaust channel between the battery cell 300 and the end cover 10 in the Z-axis direction is not significant, and it can still effectively exhaust air, ensuring the safety of the energy storage device 1000.

[0122] The two snap-fit ​​sections b2 of the second bracket 40b are adjacent to and spaced apart from the two end walls 321 of the second through groove 32. Each snap-fit ​​section b2 is located between a first groove 35a and a second groove 35b that are arranged opposite to each other. The two second snap-fit ​​grooves b22 of the snap-fit ​​section b2 are engaged with the hooks 36 on the first groove 35a and the second groove 35b respectively, so that the second bracket 40b is fixedly connected to the lower plastic 20.

[0123] The two third sides b13 of the bracket body b1 face the gaps between the multiple second protrusions 33, and each third leg b3 of the second bracket 40b corresponds to one second protrusion 33. The gaps between the multiple third legs b3 and the gaps between the multiple second protrusions 33 are connected one-to-one, so that the ventilation channel Q2 formed between the subsequent end cap 10 and the second bracket 40b is connected to the gaps between the multiple second protrusions 33, so that gas can enter the second channel 32. Moreover, along the length of the end cap assembly 100, the projection of each third leg b3 is completely located within the projection of the adjacent second protrusion 33. When the subsequent end cap assembly 100 is mounted on the battery cell 300, along the arrangement direction (i.e., the Y-axis direction) from the tabs led out of the battery cell 300 to the second bracket 40b, each second protrusion 33 can completely block the adjacent third leg b3, preventing the tabs from contacting the third leg b3 and causing a short circuit.

[0124] Please see Figure 16 , Figure 16 for Figure 7The diagram shows the assembly structure of the end cap assembly with the two first brackets and the second bracket.

[0125] Two first brackets 40a are mounted on the end cap 10, and both first brackets 40a are located on the side of the bottom surface 12 of the end cap 10 facing away from the top surface 11. The assembly relationship between the first bracket 40a and the end cap 10 will be described below using one first bracket 40a as an example.

[0126] Specifically, along the length of the end cap 10, each first bracket 40a is located on the side of the first pole post hole 13 away from the explosion-proof hole 14, and the first bracket 40a is spaced apart from the first pole post hole 13. The length direction of the first bracket 40a is approximately the same as the width direction of the end cap 10, and the width direction is approximately the same as the length direction of the end cap 10.

[0127] Along the thickness direction of the end cap 10, the first upper surface a11 of the support body a1 and the bottom surface 12 of the end cap 10 are positioned opposite each other and spaced apart, forming an airflow channel Q1 between the support body a1 and the end cap 10. Two snap-fit ​​bodies a2, a first support leg a3, and a second support leg a4 are all located between the end cap 10 and the support body a1. Each snap-fit ​​body a2 is inserted into a third positioning groove 16c of the end cap 10, each support body a32 of the first support leg a3 is inserted into a first positioning groove 16a of the end cap 10, and the second support leg a4 is inserted into a second positioning groove 16b, thereby achieving positioning between the first support 40a and the end cap 10. When the energy storage device 1000 experiences thermal runaway, the lower plastic 20 melts and fails. A large amount of gas and the battery cell 300 compress the first support 40a. The first support 40a cooperates with multiple positioning grooves 16 to limit its movement relative to the end cover 10 in a direction perpendicular to the thickness of the end cover 10 after being subjected to compressive force. Moreover, the two snap-fit ​​bodies a2 of the first support 40a, the two support bodies a32 of the first support leg a3, and the second support leg a4 all support the end cover 10, reducing the degree of deformation of the first support 40a towards the end cover 10. This ensures that there is sufficient gas passage area between the first support 40a and the end cover 10 for gas to pass through, preventing gas accumulation and increased gas pressure. This prevents the energy storage device 1000 from exploding or the casing 200 from cracking, thus improving the safety of the energy storage device 1000.

[0128] In this embodiment, the two snap-fit ​​bodies a2 of the first bracket 40a, the two support bodies a32 of the first leg a3, and the second leg a4 protrude from the first surface 21 of the lower plastic 20 at approximately the same height L, and the height L is less than or equal to the groove depth L1 of the positioning groove 16, so as to achieve effective limiting cooperation between the first bracket 40a and the multiple positioning grooves 16 of the end cap 10.

[0129] In this embodiment, the shapes of the two matching snap-fit ​​bodies a2, the two support bodies a32 of the first support a3, and the multiple positioning grooves 16 of the second support a4 are not the same, so as to ensure that the first bracket 40a will not be installed backwards when it is assembled with the end cover 10, thereby improving the assembly efficiency.

[0130] The second bracket 40b is mounted on the end cap 10. The second bracket 40b is located on the side of the bottom surface 12 of the end cap 10 facing away from the top surface 11, and the second bracket 40b is provided corresponding to the explosion-proof hole 14 of the end cap 10. The length direction of the second bracket 40b is approximately the same as the width direction of the end cap 10, and the width direction is approximately the same as the length direction of the end cap 10.

[0131] Specifically, along the thickness direction of the end cap 10, the second upper surface b11 of the bracket body b1 is opposite to and spaced apart from the bottom surface 12 of the end cap 10, and the bracket body b1 and the end cap 10 form a ventilation channel Q2. Two snap-fit ​​sections b2 and multiple third legs b3 are located between the end cap 10 and the bracket body b1, and the two snap-fit ​​sections b2 and multiple third legs b3 abut against the bottom surface 12 of the end cap 10. When the energy storage device 1000 experiences thermal runaway, the lower plastic 20 melts and fails. A large amount of gas and the battery cell 300 compress the second support 40b. The two snap-fit ​​sections b2 and multiple third legs b3 of the second support 40b are supported by the end cover 10, reducing the degree of deformation of the second support 40b towards the end cover 10. This ensures that there is sufficient gas passage area between the second support 40b and the end cover 10 for gas to pass through, preventing gas accumulation and increased gas pressure. This prevents the energy storage device 1000 from exploding or the casing 200 from cracking, thus improving the safety of the energy storage device 1000.

[0132] Please refer to the following: Figure 6 , Figure 7 and Figure 17 , Figure 17 for Figure 5 The diagram shows a cross-sectional view of the end cap assembly along BB.

[0133] like Figure 6 , Figure 7 and Figure 17 As shown, the assembly consists of end cap 10, lower plastic 20, two first brackets 40a, second brackets 40b, two first insulating parts 51, second insulating parts 52, protective sheet 70, explosion-proof valve 60, two pole posts 80, two sealing rings 92, two pressure blocks 93, and two upper plastic parts 91.

[0134] Specifically, the explosion-proof valve 60 and the protective plate 70 are installed in the explosion-proof hole 14 of the end cap 10. The end cap 10 and the lower plastic 20 are stacked along the Z-axis direction, and the bottom surface 12 of the end cap 10 and the first surface 21 of the lower plastic 20 are connected. Each limiting post 38 of the lower plastic 20 is received in a limiting groove 15 of the end cap 10 to achieve limiting and fixing of the end cap 10 and the lower plastic 20. The explosion-proof hole 14 of the end cap 10 and the second through groove 32 of the lower plastic 20 are opposite and connected, and along the Z-axis direction, the projection of the explosion-proof hole 14 is completely located in the second through groove 32. Each first pole hole 13 of the end cap 10 and a second pole hole 23 of the lower plastic 20 are coaxially arranged and connected. Each upper plastic 91 is installed on the side of the end cap 10 opposite to the lower plastic 20. Each pressure block 93 is installed on the side of an upper plastic 91 opposite to the end cap 10. Each electrode post 80 is sequentially inserted through the second electrode post hole 23 of the lower plastic 20, the first electrode post hole 13 of the end cap 10, an upper plastic 91, and a pressure block 93, and is connected and fixed to the pressure block 93. Each sealing ring 92 is fitted around the outer periphery of an electrode post 80 and is clamped in the gap between the lower plastic 20, the end cap 10, the electrode post 80, and the upper plastic 91 to seal the gap.

[0135] Each first bracket 40a is provided corresponding to a first through groove 25 of the lower plastic 20 and is fixedly positioned with the end cap 10. The airflow channel Q1 between the first bracket 40a and the end cap 10 is connected to the air guide groove 27, multiple air guide holes 26, the first through groove 25, and the exhaust hole 29 of the lower plastic 20. The second bracket 40b is provided corresponding to the second through groove 32 of the lower plastic 20, and the ventilation channel Q2 between the second bracket 40b and the end cap 10 is connected to the gap between the multiple second protrusions 33 of the lower plastic 20 and the second through groove 32. When thermal runaway occurs in the energy storage device 1000, the gas rising from the side of the cell 300 can flow smoothly through the gas guide groove 27, multiple gas guide holes 26, the first through groove 25, the airflow channel Q1, the exhaust hole 29, the gap between multiple second protrusions 33, the ventilation channel Q2, and the second through groove 32, and flow to the explosion-proof structure through the second through groove 32. After the explosion-proof valve 60 is opened, the gas can be discharged to the outside of the energy storage device 1000, ensuring good exhaust performance of the end cover assembly 100, avoiding the accumulation of gas inside the energy storage device 1000, which could cause the energy storage device 1000 to explode or the shell 200 to crack, thus improving the safety performance of the energy storage device 1000.

[0136] Please refer to the following: Figure 5 and Figure 17Along the thickness direction of the end cap assembly 100, each first insulating member 51 completely covers the side of a first bracket 40a facing away from the end cap 10, and the projection of the first insulating member 51 at least partially coincides with the projection of the first boss 24. The second insulating member 52 completely covers the side of the second bracket 40b facing away from the end cap 10, and the projection of the second insulating member 52 at least partially coincides with the projection of the second boss 33.

[0137] Please see Figure 3 The end cap assembly 100 is mounted on one side of the battery cell 300 in the height direction, and the electrode post 80 is welded to the electrode tabs led out from the battery cell 300 for electrical connection. The two first protrusions 24 and multiple second protrusions 33 of the lower plastic 20 press against the battery cell 300, serving to limit the battery cell 300, separate the battery cell 300 from the end cap 10, and form an exhaust channel. The electrode tabs led out from the battery cell 300 are located between the second protrusions 33 and the two first protrusions 24. The two first supports 40a and the second support 40b located inside the lower plastic 20 have higher melting points than the lower plastic 20. When the energy storage device 1000 experiences thermal runaway, even if the lower plastic 20 melts and fails, the two first supports 40a and the second support 40b remain structurally stable and can provide good support between the battery cell 300 and the end cap 10. They also limit the movement of the battery cell 300, preventing adverse effects such as the battery cell 300 moving towards the end cap 10 inside the energy storage device 1000, blocking the venting channel between the end cap 10 and the battery cell 300, or short-circuiting the battery cell 300 and the end cap 10. This improves the venting performance of the end cap assembly 100 and the stability of the internal structure of the energy storage device 1000, thereby enhancing the safety and reliability of the energy storage device 1000.

[0138] In existing technologies, when a battery experiences thermal runaway, a large amount of high-temperature gas is violently generated inside. This high-temperature gas needs to be expelled from the battery to ensure its safety. During the expulsion of these high-temperature gases, the lower insulation components may melt, deform, or even catch fire. The lower plastic casing loses its supporting function. Simultaneously, the high-temperature gas pushes the battery cells upwards towards the top cover, potentially blocking the venting channels between the cells and the top cover. This makes it difficult for the large amount of gas inside the battery to escape in time, causing the internal gas pressure to rise and potentially leading to battery explosions, casing cracks, and other problems, thus posing a significant safety hazard.

[0139] In this embodiment, the end cap 10 assembly 100 includes two first supports 40a, an end cap 10, and a lower plastic 20. The end cap 10 and the lower plastic 20 are stacked along the thickness direction of the end cap 10 assembly 100. The lower plastic 20 is provided with two first protrusions 24 and two first through slots 25. The two first protrusions 24 are respectively located at both ends of the lower plastic 20 in the length direction. Each first through slot 25 and a first protrusion 24 are correspondingly provided and penetrate through both sides of the lower plastic 20 in the thickness direction. The two first protrusions 24 are used to press against the battery cell 300 to separate and insulate the battery cell 300 from the end cap 10, ensuring that there is an exhaust channel between the battery cell 300 and the end cap 10. The bottom wall 254 of the first through groove 25 is provided with a vent hole 26, and the wall surface of the bottom wall 254 facing away from the opening of the first through groove 25 is recessed with a vent groove 27, which penetrates the wall surface of the first groove side wall 251 facing the second groove side wall 252. The vent groove 27, the vent hole 26, and the first through groove 25 are connected to each other, so as to prevent the vent hole 26 from being blocked and preventing gas from entering the first through groove 25 when the first protrusion 24 abuts against the battery cell 300. The second groove side wall 252 of the first through groove 25 is provided with an exhaust hole 29, which is connected to the first through groove 25. Through the vent groove 27, the vent hole 26, the first through groove 25, and the exhaust hole 29, the gas rising from the side of the battery cell 300 can flow smoothly through the end of the lower plastic 20, avoiding gas accumulation and pressure increase, and ensuring the safety of the energy storage device 1000. Each first support 40a is housed within a first through slot 25 and fixed to the lower plastic 20, also serving to support the end cap 10. The melting point of the first support 40a is greater than that of the lower plastic 20. In the event of thermal runaway of the energy storage device 1000, even if the lower plastic 20 fails, the first support 40a remains structurally stable. A large amount of gas and the battery cell 300 compress the first support 40a, which can effectively support the first support 40a between the battery cell 300 and the end cap 10. This ensures that there is sufficient channel between the battery cell 300 and the end cap 10 for the gas rising from the side of the battery cell 300 to pass through, preventing the gas inside the energy storage device 1000 from being unable to escape in time, which could lead to increased gas pressure and subsequently cause explosions or cracking of the casing 200. This improves the venting performance of the end cap 10 and the end cap assembly 100, thereby enhancing the safety of the energy storage device 1000.

[0140] Furthermore, the lower plastic 20 is provided with a second through groove 32 and a plurality of second protrusions 33. Along the length of the lower plastic 20, the plurality of second protrusions 33 are provided on both sides of the second through groove 32. The plurality of second protrusions 33 are used to press against the battery cell 300 to further separate and insulate the battery cell 300 and the end cap 10, ensuring that there is an exhaust channel between the battery cell 300 and the end cap 10. The end cap assembly 100 also includes a second bracket 40b, which is spaced between two first brackets 40a, housed in the second through groove 32, and supported on the end cap 10. A ventilation channel Q2 is formed between the second bracket 40b and the end cap 10. The ventilation channel Q2 communicates with the gap between the plurality of second protrusions 33 and the second through groove 32 to allow gas to pass through. The melting point of the second support 40b is greater than that of the lower plastic 20. In the event of thermal runaway of the energy storage device 1000, even if the lower plastic 20 fails, the second support 40b remains structurally stable. A large amount of gas and the battery cell 300 compress the second support 40b, which can effectively support the battery cell 300 and the end cap 10. This ensures that there is a sufficient channel for gas to pass through between the battery cell 300 and the end cap 10, preventing the gas inside the energy storage device 1000 from being unable to be discharged in time, which could lead to increased gas pressure and cause problems such as explosion or cracking of the casing 200. This improves the venting performance of the end cap 10 and the end cap assembly 100, and enhances the safety of the energy storage device 1000.

[0141] Please see Figure 18 , Figure 18 for Figure 7 A schematic diagram of the structure of the lower plastic of the end cap assembly 100 shown in a second embodiment.

[0142] In this embodiment, unlike the structure of the lower plastic 20 in the first embodiment described above, the lower plastic 20 in this embodiment also includes a connecting rib 39. The connecting rib 39 protrudes from the second surface 22 of the lower plastic 20 and extends along the width direction of the lower plastic 20. The connecting rib 39 is connected to a plurality of second protrusions 33 on one side of the second through groove 32 in the length direction of the lower plastic 20, and the connecting rib 39 is located on the side of the plurality of second protrusions 33 facing away from the second through groove 32. It can also be understood that a portion of the connecting rib 39 constitutes the fourth groove sidewall 352 of the plurality of grooves 35 provided corresponding to the plurality of second protrusions 33. The second bracket 40b is mounted on the lower plastic 20, and the surface of the connecting rib 39 away from the second surface 22 protrudes from the second lower surface b12 of the second bracket 40b to ensure that the connecting rib 39 can completely cover the second bracket 40b in the length direction of the lower plastic 20.

[0143] The number of connecting ribs 39 can be one or more. In this embodiment, there are two connecting ribs 39. The two connecting ribs 39 are located on opposite sides of the plurality of protrusions along the length of the lower plastic 20. Part of one connecting rib 39 forms the fourth groove sidewall 352 of the plurality of first grooves 35a, and part of the other connecting rib 39 forms the fourth groove sidewall 352 of the plurality of second grooves 35b. The connecting ribs 39 not only increase the structural strength of the lower plastic 20, but also block the gaps between the plurality of second protrusions 33 in the width direction of the lower plastic 20, thereby completely blocking the possibility of the electrode tabs led out by the battery cell 300 overlapping with the second support 40b in the second through groove 32, avoiding short circuit between the battery cell 300 and the second support 40b, and ensuring the safety of the energy storage device 1000.

[0144] In this embodiment, the same contents as those in the first embodiment above, such as the structure and material of the lower plastic 20 and the assembly relationship between the lower plastic 20 and the second bracket 40b, will not be repeated here.

[0145] Please see Figure 19 , Figure 19 for Figure 3 A bottom view of a second embodiment of the second insulating member 52 of the end cap assembly 100 assembled with the second bracket 40b.

[0146] In this embodiment, unlike the structure of the second insulating member 52 in the first embodiment described above, the second insulating member 52 in this embodiment further includes a plurality of insulating holes 521. The plurality of insulating holes 521 penetrate both surfaces of the second insulating member 52 in the thickness direction and are spaced apart from each other. Each insulating hole 521 is positioned opposite to and communicates with a vent hole b4 of the second bracket 40b, allowing gas to pass through the second insulating member 52 and enter the vent hole b4 of the second bracket 40b, thereby increasing the channel area for gas to enter the second through groove 32 and improving the exhaust performance of the end cap assembly 100.

[0147] In this embodiment, the size of each insulating hole 521 is smaller than the size of a vent hole b4 in the second bracket 40b. That is, along the Z-axis direction, the projection of each insulating hole 521 is located within the projection of a vent hole b4. Along the width direction (i.e., the Y-axis direction) of the second bracket 40b, each vent hole b4 has two opposing and spaced-apart first sides b41, with an opening distance F between the two first sides b41. Along the width direction (i.e., the Y-axis direction) of the second insulating member 52, each insulating hole 521 has two opposing and spaced-apart second sides 522. The distance between the two second sides 522 of each insulating hole 521 is smaller than the opening distance F of the corresponding vent hole b4, and each second side 522 is adjacent to and spaced apart from a first side b41, with an assembly distance T between each second side 522 and an adjacent first side b41. The assembly distance T is greater than or equal to 0.1 mm, and the ratio of the assembly distance T to the opening distance F is less than or equal to 0.4. This ensures both the insulation performance and the venting performance of the second insulating component 52. Most preferably, the assembly distance T is greater than or equal to 0.5 mm and less than or equal to 2 mm. This avoids situations where the assembly distance T is too small, resulting in low manufacturability of the second insulating component 52 and inability to effectively cover the second bracket 40b, thus compromising its insulation performance. Simultaneously, it avoids situations where the assembly distance T is too large, leading to significant loss of venting effect.

[0148] In this embodiment, the structure, material, and assembly relationship between the second insulating member 52, the second bracket 40b, and the lower plastic 20 are the same as in the first embodiment described above, and will not be repeated here.

[0149] The above are merely some embodiments and implementation methods of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An end cap assembly, characterized in that, The end cap assembly includes: End cap; The lower plastic includes a first surface and a second surface, which are disposed opposite to each other along the thickness direction of the lower plastic. The lower plastic also includes two first through grooves and two first bosses. The two first bosses protrude from the second surface in a direction away from the first surface and are respectively located at both ends of the length direction of the lower plastic. The first boss has a boss surface, which faces the same direction as the second surface. Along the thickness direction of the lower plastic, each first through groove penetrates the first surface and the boss surface. The first channel includes a first channel sidewall, a second channel sidewall, two channel end walls, and a channel bottom wall. The first channel sidewall and the second channel sidewall are opposite to each other and spaced apart along the length direction of the lower plastic. The two channel end walls are opposite to each other and spaced apart along the width direction of the lower plastic and are connected to the first channel sidewall and the second channel sidewall. The channel bottom wall is connected to the first channel sidewall and spaced apart from the second channel sidewall. The channel bottom wall and the boss surface are opposite to each other along the thickness direction of the lower plastic. The lower plastic also includes a vent hole and a vent hole. The vent hole penetrates both sides of the bottom wall of the groove in the thickness direction, and the vent hole penetrates both sides of the side wall of the second groove in the thickness direction. Both the vent hole and the vent hole are connected to the outside of the first through groove and the lower plastic. Two first supports extend along the width direction of the end cap assembly, and the melting point of both first supports is greater than the melting point of the lower plastic. Along the thickness direction of the end cap assembly, the end cap and the lower plastic are stacked and connected, the first surface faces the end cap, each first bracket is received in a first through groove and fixed to the lower plastic, and is used to support the end cap; The lower plastic also includes an air guide groove, which is recessed from the boss towards the bottom wall of the groove and penetrates the wall surface of the first groove sidewall toward the second groove sidewall. Along the thickness direction of the lower plastic, the projection of the air guide groove and the projection of the air guide hole partially coincide, and the air guide groove is connected to the air guide hole, the first through groove and the outside of the lower plastic.

2. The end cap assembly according to claim 1, characterized in that, Along a direction perpendicular to the thickness direction of the end cap assembly, there are assembly gaps between the edge of the first bracket and the first groove sidewall, the two groove endwalls, the groove bottom wall and the second groove sidewall, and the assembly gaps are greater than or equal to 0.1 mm.

3. The end cap assembly according to claim 1, characterized in that, Along the length of the lower plastic, a first reinforcing rib is connected between the bottom wall of the groove and the side wall of the second groove. Along the thickness of the lower plastic, the first reinforcing rib is recessed relative to the boss surface.

4. The end cap assembly according to claim 3, characterized in that, The bottom wall of the trough is provided with a side plate, which is connected to the side wall of the first trough and is spaced apart from the side wall of the second trough along the length of the lower plastic; the first reinforcing rib is connected to the side plate.

5. The end cap assembly according to claim 1, characterized in that, The first support includes a support body, which is housed within the first through groove and located between the side wall of the second groove and the bottom wall of the groove; Along the thickness direction of the end cap assembly, the bracket body is positioned opposite and spaced apart from the end cap. The surface of the bracket body facing away from the end cap is recessed relative to the boss surface and has a height difference with the boss surface. The height difference is greater than or equal to 0.1 mm and is less than or equal to one-third of the overall height of the first bracket in the thickness direction of the end cap assembly.

6. The end cap assembly according to claim 5, characterized in that, The first bracket also includes two snap-fit ​​bodies. Along the length of the first bracket, the two snap-fit ​​bodies are respectively protruding on both sides of the bracket body and extending toward the end cap. The bottom wall of the groove is provided with a buckle, which is adjacent to the end wall of the groove, and the snap-fit ​​body is snapped and fixed to the buckle.

7. The end cap assembly according to claim 6, characterized in that, The first bracket also includes a first leg and a second leg. Along the width direction of the first bracket, the first leg and the second leg are respectively connected to both sides of the bracket body and extend toward the end cap. Along the length direction of the lower plastic, the first leg and the second leg are completely staggered. The bottom wall of the tank is provided with a first clearance notch, which penetrates the bottom wall of the tank and exposes the first side wall of the tank. The second side wall of the tank is provided with a second clearance notch. Along the length of the lower plastic, the first clearance notch and the second clearance notch are completely staggered. The first support leg is accommodated in the first clearance notch, and the second support leg is accommodated in the second clearance notch.

8. The end cap assembly according to claim 7, characterized in that, The end cap also includes a plurality of positioning grooves, each of which is recessed on the surface of the end cap facing the lower plastic and is spaced apart from each other. Along the thickness direction of the end cap assembly, the ends of the two snap-fit ​​bodies, the first leg, and the second leg that are away from the bracket body protrude above the first surface, and the two snap-fit ​​bodies, the first leg, and the second leg are respectively inserted into a plurality of positioning grooves, and the height of the two snap-fit ​​bodies, the first leg, and the second leg above the first surface is less than or equal to the depth of the positioning grooves.

9. The end cap assembly according to claim 8, characterized in that, The depth of each positioning groove is greater than or equal to 0.2 mm, and the ratio of the depth of each positioning groove to the thickness of the end cap is less than or equal to 0.

5.

10. The end cap assembly according to claim 8, characterized in that, The plurality of positioning grooves include a plurality of first positioning grooves, a plurality of second positioning grooves and a plurality of third positioning grooves. Along the width direction of the end cap, the plurality of first positioning grooves are spaced apart, the plurality of second positioning grooves are spaced apart, and the plurality of third positioning grooves are spaced apart. The first support leg includes a support leg body and two support bodies. The support leg body is connected to the bracket body and extends along the width direction of the first bracket. Along the length direction of the first bracket, the two support bodies are respectively bent and connected to both sides of the support leg body and extend toward the end cap. Each of the snap-fit ​​bodies is inserted into a third positioning slot, each of the second legs is inserted into a second positioning slot, and each of the supports is inserted into a first positioning slot.

11. The end cap assembly according to any one of claims 1-10, characterized in that, The lower plastic also includes a second through groove and a plurality of second protrusions. The second through groove extends through both sides of the lower plastic in the thickness direction. Along the length direction of the lower plastic, the second through groove is located between two first through grooves. The plurality of second protrusions protrude from the second surface in a direction away from the first surface and are disposed on both sides of the second through groove. The plurality of second protrusions are spaced apart along the width direction of the lower plastic and have gaps. The end cap assembly further includes a second bracket, which is received in the second through groove and located between a plurality of second protrusions on both sides of the second through groove. The second bracket is fixed to the lower plastic and supported on the end cap. A ventilation channel is formed between the second bracket and the end cap. The ventilation channel communicates with the gap between the second through groove and the plurality of second protrusions. The length direction of the second bracket extends along the width direction of the end cap assembly, and the melting point of the second bracket is greater than the melting point of the lower plastic.

12. The end cap assembly according to claim 11, characterized in that, The second bracket has a plurality of third legs spaced apart along the width direction of the end cap assembly, and the plurality of third legs are all supported on the end cap; Along the length of the end cap assembly, each of the third legs is adjacent to a second boss, and the projection of each third leg is completely within the projection of the adjacent second boss.

13. The end cap assembly according to claim 11, characterized in that, The lower plastic also includes a connecting rib, which protrudes from the second surface and extends along the width direction of the lower plastic. The connecting rib is connected to a plurality of second protrusions on one side of the second through groove in the length direction of the lower plastic, and the connecting rib is located on the side of the plurality of second protrusions facing away from the second through groove. Along the thickness direction of the end cap assembly, the surface of the connecting rib away from the second surface protrudes from the surface of the second bracket opposite to the end cap.

14. The end cap assembly according to claim 11, characterized in that, The end cap assembly further includes two first insulating members and a second insulating member. Each first insulating member is located on the side of a first bracket facing away from the end cap and completely covers the first bracket. The second insulating member is located on the side of a second bracket facing away from the end cap and completely covers the second bracket.

15. The end cap assembly according to claim 14, characterized in that, The materials of both the first insulating element and the second insulating element include at least one of PI tape, PET tape, PP tape and PI and PET composite tape.

16. The end cap assembly according to claim 14, characterized in that, The second bracket includes a vent hole that extends through both sides of the second bracket in the thickness direction. Along the length direction of the end cap assembly, the vent hole has two opposing and spaced-apart first sides with an opening distance between the two first sides. The second insulating member includes an insulating hole that penetrates both surfaces of the second insulating member in the thickness direction. Along the length direction of the end cap assembly, the insulating hole has two opposing and spaced second sides. The insulating hole and the vent hole are connected and both are connected to the venting channel. Along the thickness direction of the end cap assembly, the projection of the insulating hole is completely located within the projection of the vent hole. Along the length direction of the end cap assembly, the distance between the two second sides is less than the opening distance.

17. The end cap assembly according to claim 16, characterized in that, Along the length of the end cap assembly, each of the second side edges is adjacent to one of the first side edges and has an assembly distance greater than or equal to 0.1 mm, and the ratio of the assembly distance to the opening distance is less than or equal to 0.

4.

18. The end cap assembly according to claim 17, characterized in that, The assembly distance is greater than or equal to 0.5 mm and less than or equal to 2 mm.

19. An energy storage device, characterized in that, The energy storage device includes a housing, a battery cell, and an end cap assembly as described in any one of claims 1-18, wherein the battery cell is housed within the housing, the end cap assembly is mounted on one side of the battery cell in the height direction and sealed to the housing, and the lower plastic abuts against the battery cell.

20. An energy storage system, characterized in that, The energy storage system includes the energy storage device as described in claim 19.

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