Battery cover, battery casing, energy storage device and power supply system

Abstract

This application discloses a battery cover, a battery casing, an energy storage device, and a power supply system. The battery cover is used to seal the opening of the casing, and includes a main body and an overlapping portion. The main body includes an exposed portion and an embedded portion arranged along the thickness direction of the battery cover. The exposed portion is used to be disposed outside the casing, and the embedded portion is used to extend into the casing through the opening. The embedded portion has a stepped groove around its periphery. The overlapping portion surrounds the periphery of the exposed portion and is used to overlap with the opening surface of the casing.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more specifically, to a battery cover, a battery casing, an energy storage device, and a power supply system. Background Technology

[0002] A battery typically includes a casing and an electrode assembly disposed within the casing. The casing includes a housing and a cover plate. The housing has an opening through which the electrode assembly is inserted into the housing. The cover plate seals the opening to enclose the electrode assembly within the housing.

[0003] In related technologies, the cover plate and the housing are usually fixed by welding. Welding is prone to failure, which in turn shortens the cycle life of the battery. Utility Model Content

[0004] Therefore, in view of the shortcomings of the above-mentioned related technologies, this application provides a battery cover, a battery casing, an energy storage device, and a power supply system.

[0005] The battery cover plate of this application embodiment is used to seal the opening of the housing, and the battery cover plate includes: The main body includes an exposed portion and an embedded portion arranged along the thickness direction of the battery cover. The exposed portion is disposed outside the housing, and the embedded portion is inserted into the housing through the opening. A stepped groove is provided around the periphery of the embedded portion. An overlapping portion surrounds the periphery of the exposed portion and is used to overlap with the opening surface of the housing.

[0006] According to some embodiments of this application, the exposed portion has a first surface facing away from the embedded portion, and the groove wall of the stepped groove has a tread surface parallel to the first surface.

[0007] According to some embodiments of this application, the embedded portion has a second surface facing away from the exposed portion, and the groove wall of the stepped groove also has a kick surface connecting the tread surface and the second surface.

[0008] According to some embodiments of this application, the tread surface is perpendicularly connected to the kick surface.

[0009] The battery casing of this application embodiment includes: The shell has an opening; and A battery cover, which blocks the opening, the battery cover includes a main body and an overlapping part, the overlapping part surrounds the periphery of the main body and is connected to the opening surface of the housing, and the periphery of the portion of the main body that extends into the housing from the opening is provided with a stepped groove, the stepped groove surrounding the portion of the main body that extends into the housing; The overlapping portion, the portion of the main body near the overlapping portion, and the portion of the housing near the opening are welded to form a weld, which surrounds the periphery of the battery cover.

[0010] According to some embodiments of this application, the housing includes a cylindrical sidewall, one axial end of which is provided with the opening, and the wall thickness of the cylindrical sidewall is L1, wherein L1 satisfies: 0.4mm≤L1≤0.8mm.

[0011] According to some embodiments of this application, the weld penetration depth is L2, where L2 satisfies: 0.6mm≤L2≤1mm.

[0012] According to some embodiments of this application, the housing includes a cylindrical sidewall, the opening is provided at one axial end of the cylindrical sidewall, the wall thickness of the cylindrical sidewall is L1; the weld penetration is L2, the ratio of L2 to L1 is R1, and R1 satisfies: 1.6≤R1≤3.3.

[0013] According to some embodiments of this application, the weld width is L3, and L3 satisfies: 0.6mm≤L3≤1.3mm.

[0014] According to some embodiments of this application, the main body has a first surface facing away from the stepped groove, the groove wall of the stepped groove has a tread surface arranged parallel to the first surface, and the distance between the first surface and the tread surface is L4, where L4 satisfies: 0.45mm≤L4≤0.975mm.

[0015] According to some embodiments of this application, the weld width is L3; The main body has a first surface facing away from the stepped groove, and the groove wall of the stepped groove has a tread surface arranged parallel to the first surface. The distance between the first surface and the tread surface is L4. The ratio of L3 to L4 is R2, and R2 satisfies: 0.75≤R2≤1.

[0016] According to some embodiments of this application, the housing includes a cylindrical sidewall, and the opening is provided at one axial end of the cylindrical sidewall; The groove wall of the stepped groove has a kick surface, and the distance between the kick surface and the outer peripheral surface of the cylindrical sidewall is L5, where L5 satisfies: 1.2mm≤L5≤2mm.

[0017] According to some embodiments of this application, the weld penetration depth is L2; The housing includes a cylindrical sidewall, and the opening is provided at one axial end of the cylindrical sidewall; the groove wall of the stepped groove has a kick surface, and the distance between the kick surface and the outer peripheral surface of the cylindrical sidewall is L5; The ratio of L5 to L2 is R3, and R3 satisfies: 1≤R3≤2.

[0018] According to some embodiments of this application, the main body has a first surface disposed away from the stepped groove, and the groove wall of the stepped groove has a tread surface parallel to the first surface.

[0019] According to some embodiments of this application, the main body portion further has a second surface disposed opposite to the first surface, and the groove wall of the step groove further has a kick surface connecting the tread surface and the second surface.

[0020] According to some embodiments of this application, the tread surface is perpendicularly connected to the kick surface.

[0021] According to some embodiments of this application, the weld and the stepped groove each have an overlapping area on a target plane, and the target plane is perpendicular to the thickness direction of the battery cover.

[0022] The energy storage device of this application embodiment includes the battery casing described in any of the above claims.

[0023] The power supply system of this application embodiment includes electrical equipment and the above-mentioned energy storage device, wherein the energy storage device supplies power to the electrical equipment. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] Figure 1 A schematic diagram of an energy storage system Figure 1 .

[0026] Figure 2 A schematic diagram of an energy storage system Figure 2 .

[0027] Figure 3 This is an exploded view of the battery casing.

[0028] Figure 4 It is a partial cross-sectional view along the height and width directions of the battery after the battery cover and the housing are assembled, in which a weld is formed between the battery cover and the housing.

[0029] Figure 5 It is a partial sectional view along the height and width directions of the battery after the battery cover and housing are assembled, wherein the battery cover and housing are not welded.

[0030] Figure 6 This is a schematic diagram of a power supply system.

[0031] The reference numerals in the attached figures are explained as follows: 10. Battery casing; 100. Battery cover; 110. Main body; 110a. Exposed part; 110b. Embedded part; 111. Step groove; 1111. Kick; 1112. Tread; 113. First surface; 114. Second surface; 120. Overlapping part; 200, Shell; 210, Opening; 211, Opening surface; 220, Cylindrical sidewall; 221, Outer peripheral surface; 230, Base plate; 300. Weld seam. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed description will be omitted.

[0033] It is understood that the terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to these processes, methods, products, or devices.

[0034] Because the energy people need is highly time- and space-dependent, in order to make rational use of energy and improve energy efficiency, it is necessary to use a medium or device to store one form of energy in the same way or by converting it into another form of energy, and then release it in a specific form of energy based on future application needs.

[0035] Currently, the generation of green electricity generally relies on solar, wind, and hydropower. However, wind and solar power are generally characterized by strong intermittency and large fluctuations, which can cause grid instability, insufficient power during peak demand periods, and excessive power during off-peak periods. Unstable voltage can also damage the power grid. Therefore, insufficient electricity demand or insufficient grid capacity may lead to the problem of "wind and solar curtailment." 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.

[0036] 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.

[0037] 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 relief of grid congestion. 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 energy storage cabinets applied to the electricity consumption side mainly function as self-consumption of electricity, peak-valley price arbitrage, capacity cost management, and improvement of power supply reliability. Depending on the application scenario, electricity consumption side energy storage can be divided into industrial and commercial energy storage cabinets, household energy storage devices, energy storage charging piles, etc., which are generally used in conjunction with distributed photovoltaics. Industrial and commercial users can use energy storage for peak-valley price arbitrage and capacity cost management. In the electricity market implementing peak-valley pricing, by charging the energy storage system when the electricity price is low and discharging the energy storage system when the electricity price is high, peak-valley price arbitrage can be achieved, reducing electricity costs. In addition, industrial enterprises subject to two-part tariffs can use energy storage systems to store energy during off-peak hours and discharge during peak loads, thereby reducing peak power and the maximum demand declared, achieving the goal of reducing capacity costs. Household photovoltaics with energy storage can improve the level of self-consumption of electricity. Due to high electricity prices and poor power supply stability, the demand for household photovoltaic installations is driven. Given that photovoltaic power generation occurs during the day, while user load is generally higher at night, configuring energy storage can better utilize photovoltaic power, improve self-consumption levels, and reduce electricity costs. Furthermore, energy storage is needed in areas such as communication base stations and data centers for backup power.

[0038] In some embodiments, see Figure 1 , Figure 1 This is a schematic diagram of the structure of an energy storage system according to an embodiment of this application, and Figure 1 Taking the shared energy storage scenario on the power generation / distribution side as an example, the energy storage device in this application is not limited to the power generation / distribution side energy storage scenario.

[0039] This application provides an energy storage system, comprising: a high-voltage cable 2, a first power conversion device 3, a second power conversion device 4, and the energy storage device 1 provided in this application. In some embodiments of the power generation scenario, the second power conversion device 4 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 1 through grid connection. The energy storage device 1 is connected to the high-voltage cable 2 and outputs smooth electricity to the power consumption side of the distribution network, realizing peak shaving and frequency regulation, and ensuring stable grid operation; or, the wind power conversion device is always connected to the high-voltage cable 2. High-voltage cable 2 connects the wind power conversion device to the power distribution network under normal power generation conditions. When the current power load is low and the wind power conversion device generates excess power, the excess power is first stored in energy storage device 1 to reduce wind and solar curtailment and improve the absorption of new energy power generation. When the power load is high, the power grid issues an instruction to transmit the power stored in energy storage device 1 in conjunction with high-voltage cable 2 in grid-connected mode to the power consumption side. This provides the power grid with various services such as peak shaving, frequency regulation, and backup, giving full play to the peak shaving function of the power grid, promoting peak shaving and valley filling, and alleviating the power supply pressure on the power grid.

[0040] In some embodiments on the distribution network side, the first power conversion device 3 can be a photovoltaic power conversion device. The energy storage device 1 is connected to the high-voltage cable 2 and installed downstream of the high-voltage cable 2 between the user load and the high-voltage cable 2. The power output of the photovoltaic power conversion device is stored in the energy storage device 1, which can respond in time to act as a backup power source when the power grid / distribution network fails. Alternatively, it can provide power supply support to alleviate line blockage when the high-voltage cable 2 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.

[0041] Optionally, the first power conversion device 3 may include, but is not limited to, a wind power conversion device, and the second power conversion device 4 may include, but is not limited to, a photovoltaic power conversion device. The first power conversion device 3 and the second power conversion device 4 can convert at least one of solar energy, light energy, wind energy, thermal energy, tidal energy, biomass energy and mechanical energy into electrical energy.

[0042] In other embodiments, please refer to Figure 2 , Figure 2 A schematic diagram of the structure of an energy storage system according to another embodiment of this application, and this application Figure 1 The embodiments are illustrated using an industrial and commercial energy storage scenario as an example. The energy storage device in this application is not limited to an energy storage cabinet in an industrial and commercial energy storage scenario.

[0043] The energy storage system includes: an energy storage device 1, a high-voltage cable 2, a factory equipped with a first power conversion device 3, a photovoltaic-energy storage-charging station 7, and a vehicle 8. In some embodiments of the industrial and commercial scenario, the first power conversion device 3 can be a photovoltaic panel, which converts solar energy into electrical energy and stores it in the energy storage device 1 in the factory. In the event of a power grid outage, the energy storage device 1 provides power to ensure the safe and stable operation of the factory without interruption. Alternatively, when the factory's power load is high, the power grid issues an instruction to transmit the electricity stored in the energy storage device 1 in conjunction with the high-voltage cable 2 in a grid-connected mode to supply the factory with electricity, providing various services such as peak shaving / frequency regulation and backup for the power grid operation. In addition, the first power conversion device 3 can also convert solar energy into electrical energy and store it in the energy storage device 1 of the photovoltaic-energy storage-charging station 7, directly charging the vehicle 8 through the photovoltaic-energy storage-charging station 7, which is fast and convenient.

[0044] Optionally, the energy storage device 1 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.

[0045] Optionally, the energy storage device 1 can be, but is not limited to, a single battery (secondary battery), a battery module composed of single batteries, a battery pack, an energy storage cabinet, an energy storage container, etc. The actual application form of the energy storage device 1 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 1.

[0046] As for individual batteries, they can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc. Individual batteries can be cylindrical, flat, cuboid, etc., and the embodiments of this application do not limit them.

[0047] like Figure 3 As shown, the following description uses a single battery as an example of an energy storage device. The energy storage device 1 includes a battery casing 10 and an electrode assembly (not shown in the figure). The battery casing 10 includes a battery cover 100 and a housing 200. The housing 200 has an opening 210. The electrode assembly is inserted into the housing 200 through the opening 210. The battery cover 100 is welded to the housing 200 to seal the opening 210 of the housing 200, thereby enclosing the electrode assembly inside the housing 200.

[0048] like Figure 3 As shown, in an exemplary embodiment, the housing 200 is cuboid in shape and includes a cylindrical sidewall 220 and a bottom plate 230. The cylindrical sidewall 220 is a rectangular cylindrical structure with openings at both ends. The bottom plate 230 is connected to one end of the cylindrical sidewall 220 to block one of the openings of the cylindrical sidewall 220, and the battery cover 100 blocks the other opening.

[0049] Of course, in other embodiments, the housing 200 may also be a cylindrical structure, forming an annular structure. The cylindrical structure has openings at both axial ends, and each opening can be sealed by a battery cover 100.

[0050] The shape of the battery cover 100 can be, but is not limited to, a rectangular plate structure, a disc structure, etc.

[0051] The inventors of this application discovered in their research that after the battery cover plate 100 of the battery casing 10 is welded to the casing 200, welding failure is prone to occur on the casing 200. Further research revealed that the width of the heat-affected zone (HAZ) on the inner wall of the casing 200 is typically greater than that on the outer wall. This is partly because the welding heat from the battery cover plate 100 is conducted to the inner wall of the casing 200, resulting in a higher temperature on the inner wall than the outer wall. Another reason is that during welding, the heat from the casing 200 is also conducted to the battery cover plate 100, but because the battery cover plate 100 itself contains heat, this heat is difficult to dissipate, leading to heat accumulation on the inner wall of the casing 200. The width of the HAZ is directly proportional to the heat residence time; the longer the heat residence time, the wider the HAZ, resulting in more severe lattice coarsening of the base material around the molten pool, poorer fatigue performance, and a greater susceptibility to cracking later.

[0052] Based on this, the present application embodiment improves the structure of the battery cover 100 to solve the problem that the housing 200 is prone to welding failure.

[0053] like Figure 4 As shown, the battery cover 100 includes a main body 110 and an overlapping portion 120. The overlapping portion 120 surrounds the periphery of the main body 110 and is adjacent to the opening surface 211 of the housing 200. Figure 5 The main body 110 is connected by a stepped groove 111 around the part of the main body 110 that extends into the housing 200 through the opening 210. The stepped groove 111 surrounds the part of the main body 110 that extends into the housing 200. The overlapping part 120, the part of the main body 110 near the overlapping part 120, and the part of the housing 200 near the opening 211 are welded to form a weld 300, which surrounds the periphery of the battery cover 100.

[0054] In this embodiment, the circumferential side of the portion of the main body 110 that extends into the housing 200 through the opening 210 is provided with a stepped groove 111. The stepped groove 111 reduces the heat conduction efficiency between the housing 200 and the battery cover 100, which reduces the heat transfer from the battery top cover to the housing 200 and helps to increase the heat diffusion rate of the housing 200, thereby reducing the width of the heat-affected zone on the inner wall of the housing 200 and improving the fatigue life of the housing 200.

[0055] The opening surface 211 of the housing 200 refers to the side surface of the housing 200 where the opening 210 is located.

[0056] In one embodiment, the weld 300 and the stepped groove 111 each have overlapping regions on a target plane whose orthographic projections overlap, and the target plane is perpendicular to the thickness direction of the battery cover 100. This helps to improve the welding strength and allows the heat conducted to the housing 200 during welding to dissipate better, further reducing the width of the heat-affected zone on the inner wall of the housing 200 and improving the fatigue life of the housing 200.

[0057] like Figure 4 As shown, the housing 200 includes a cylindrical sidewall 220, with an opening 210 at one axial end of the cylindrical sidewall 220. The wall thickness of the cylindrical sidewall 220 is L1, and L1 satisfies: 0.4mm≤L1≤0.8mm.

[0058] In this embodiment, the wall thickness of the cylindrical sidewall 220 is neither too thin nor too thick. The wall thickness is designed to be not too thin to ensure the welding strength between the housing 200 and the battery cover 100, thereby ensuring the sealing of the battery casing 10; the wall thickness is designed to be not too thick to ensure that there is enough space inside the battery casing 10 to accommodate larger electrode components and improve the energy density of the battery.

[0059] like Figure 4 As shown, the penetration depth of weld 300 is L2, which satisfies: 0.6mm≤L2≤1mm. Since the weld width of weld 300 is strongly related to the position of the weld spot and the welding power, and the penetration depth directly depends on the welding power, increasing the penetration depth can indirectly increase the weld width. Therefore, L2 satisfies 0.6mm≤L2≤1mm, which can achieve a larger weld width while ensuring the welding reliability of battery cover 100 and shell 200.

[0060] In one embodiment, the ratio of L2 to L1 is R1, and R1 satisfies: 1.6≤R1≤3.3. R1 satisfies 1.6≤R1≤3.3, which can ensure the yield of the battery cover 100 and the shell 200 after welding, and also avoid the leakage of the weld pool.

[0061] Please continue reading. Figure 4 The weld width of weld 300 is L3, which satisfies the following condition: 0.6mm≤L3≤1.3mm. The fact that L3 satisfies 0.6mm≤L3≤1.3mm ensures the welding strength between battery cover 100 and casing 200.

[0062] The main body 110 has a first surface 113 facing away from the stepped groove 111, and a second surface 114 facing away from the first surface 113. The groove wall of the stepped groove 111 has a tread surface 1112 and a riser surface 1111. The tread surface 1112 is arranged parallel to the first surface 113, and the riser surface 1111 connects the tread surface 1112 and the second surface 114. The distance between the first surface 113 and the tread surface 1112 is L4, which satisfies: 0.45mm ≤ L4 ≤ 0.975mm.

[0063] In this embodiment, L4 satisfies 0.45mm≤L4≤0.975mm, which can reduce the efficiency of heat conduction from the molten pool on the battery cover 100 to the housing 200, thereby preventing the heat on the battery cover 100 from affecting the width of the heat-affected zone of the housing 200 too much.

[0064] The stepped groove 111 is formed by the second surface 114 of the main body 110 and the concave side surface of the main body 110.

[0065] In one embodiment, the ratio of L3 to L4 is R2, where R2 satisfies: 0.75≤R2≤1.

[0066] Please continue reading. Figure 4 The distance between the kick surface 1111 and the outer peripheral surface 221 of the cylindrical sidewall 220 is L5, and L5 satisfies: 1.2mm≤L5≤2mm.

[0067] In this embodiment, the distance between the kick surface 1111 of the stepped surface and the outer peripheral surface 221 of the cylindrical sidewall 220 is L5, and L5 satisfies 1.2mm≤L5≤2mm, so that the width of the stepped groove 111 is large enough, which reduces the heat conduction efficiency between the battery cover 100 and the housing 200, and avoids the heat of the battery cover 100 from affecting the width of the heat-affected zone of the inner wall surface of the housing 200 too much.

[0068] In one embodiment, the ratio of L5 to L2 is R3, where R3 satisfies: 1≤R3≤2.

[0069] Please continue reading. Figure 4 In one exemplary embodiment, the tread 1112 is perpendicularly connected to the riser 1111.

[0070] Of course, in other embodiments, the tread 1112 and the riser 1111 may not be perpendicular. For example, the tread 1112 and the riser 1111 may be arranged at an obtuse angle or at an acute angle.

[0071] Furthermore, the tread 1112 and the first surface 113 may not be parallel; for example, the tread 1112 and the first surface 113 may form an acute angle.

[0072] like Figure 5As shown, this application also provides a battery cover 100, wherein... Figure 5 The battery cover 100 has not yet been welded to the housing 200. The battery cover 100 includes a main body 110 and an overlapping portion 120. The main body 110 includes an exposed portion 110a and an embedded portion 110b arranged along the thickness direction of the battery cover 100. The exposed portion 110a is used to be disposed outside the housing 200, and the embedded portion 110b is used to extend into the housing 200 through the opening 210. The periphery of the embedded portion 110b is provided with a stepped groove 111, which surrounds the embedded portion 110b. The overlapping portion 120 surrounds the periphery of the exposed portion 110a and is used to overlap with the opening surface 211 of the housing 200.

[0073] Before welding the battery cover 100 to the housing 200, the battery cover 100 is first fastened to the opening 210 of the housing 200 so that the overlapping part 120 of the battery cover 100 overlaps the opening surface 211 of the housing 200. At this time, the insert 110b extends into the housing 200, and the stepped groove 111 on the periphery of the insert 110b is also located in the housing 200.

[0074] When the overlapping part 120 is welded to the housing 200, a stepped groove 111 is provided on the periphery of the embedded part 110b. The stepped groove 111 reduces the heat conduction efficiency between the housing 200 and the battery cover 100, which reduces the heat transfer from the battery top cover to the housing 200 and helps to increase the heat diffusion rate of the housing 200, reduces the width of the heat-affected zone on the inner wall of the housing 200, and improves the fatigue life of the housing 200.

[0075] In one embodiment, the exposed portion 110a has a first surface 113 facing away from the embedded portion 110b, and the embedded portion 110b has a second surface 114 facing away from the exposed portion 110a. The groove wall of the stepped groove 111 has a tread surface 1112 and a kick surface 1111, the tread surface 1112 being parallel to the first surface 113, and the kick surface 1111 connecting the tread surface 1112 and the second surface 114.

[0076] In one exemplary embodiment, the tread 1112 is perpendicularly connected to the riser 1111.

[0077] Of course, in other embodiments, the tread 1112 and the riser 1111 may not be perpendicular. For example, the tread 1112 and the riser 1111 may be arranged at an obtuse angle or at an acute angle.

[0078] Furthermore, the tread 1112 and the first surface 113 may not be parallel; for example, the tread 1112 and the first surface 113 may form an acute angle.

[0079] like Figure 6As shown, this application provides a power supply system 6, including an electrical device 5 and the aforementioned energy storage device 1, wherein the energy storage device 1 supplies power to the electrical device 5.

[0080] It is understood that the various embodiments / implementations provided in this application can be combined with each other without creating contradictions, and will not be described one by one here.

[0081] In the embodiments of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0082] In the description of the embodiments of the application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the application and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the application.

[0083] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the claims. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0084] The above are merely preferred embodiments of the application examples and are not intended to limit the application examples. For those skilled in the art, the application examples can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the application examples should be included within the protection scope of the application examples.

Claims

1. A battery cover plate for sealing an opening (210) of a housing (200), characterized in that The battery cover includes: The main body (110) includes an exposed portion (110a) and an embedded portion (110b) arranged along the thickness direction of the battery cover. The exposed portion (110a) is disposed outside the housing (200), and the embedded portion (110b) is inserted into the housing (200) through the opening (210). A stepped groove (111) is provided on the periphery of the embedded portion (110b), and the stepped groove (111) surrounds the embedded portion (110b). An overlap (120) surrounds the periphery of the exposed portion (110a) and is used to overlap with the opening surface (211) of the housing (200).

2. The battery cover plate of claim 1, wherein, The exposed portion (110a) has a first surface (113) facing away from the embedded portion (110b), and the groove wall of the stepped groove (111) has a tread surface (1112) parallel to the first surface (113).

3. The battery cover plate of claim 2, wherein, The embedded part (110b) has a second surface (114) facing away from the exposed part (110a), and the groove wall of the stepped groove (111) also has a kick surface (1111) connecting the tread (1112) and the second surface (114).

4. The battery cover plate of claim 3, wherein, The tread (1112) is perpendicularly connected to the kick surface (1111).

5. A battery housing, characterized by include: The housing (200) has an opening (210); as well as A battery cover (100) seals the opening (210). The battery cover (100) includes a main body (110) and an overlapping part (120). The overlapping part (120) surrounds the periphery of the main body (110) and is connected to the opening surface (211) of the housing (200). A stepped groove (111) is provided on the periphery of the portion of the main body (110) that extends into the housing (200) from the opening (210). The stepped groove (111) surrounds the portion of the main body (110) that extends into the housing (200). The overlapping portion (120), the portion of the main body (110) near the overlapping portion (120), and the portion of the housing (200) near the opening surface (211) are welded to form a weld (300), which surrounds the periphery of the battery cover (100).

6. The battery case of claim 5, wherein, The housing (200) includes a cylindrical sidewall (220), and the opening (210) is provided at one axial end of the cylindrical sidewall (220). The wall thickness of the cylindrical sidewall (220) is L1, and L1 satisfies: 0.4mm≤L1≤0.8mm.

7. The battery case of claim 5, wherein, The penetration depth of the weld (300) is L2, and L2 satisfies: 0.6mm≤L2≤1mm.

8. The battery case of claim 5, wherein, The housing (200) includes a cylindrical sidewall (220), one axial end of which is provided with the opening (210), and the wall thickness of the cylindrical sidewall (220) is L1; the penetration depth of the weld (300) is L2, and the ratio of L2 to L1 is R1, where R1 satisfies: 1.6≤R1≤3.

3.

9. The battery case of claim 5, wherein, The weld width (300) is L3, which satisfies: 0.6mm≤L3≤1.3mm.

10. The battery case of claim 5, wherein, The main body (110) has a first surface (113) facing away from the stepped groove (111). The groove wall of the stepped groove (111) has a tread surface (1112) arranged parallel to the first surface (113). The distance between the first surface (113) and the tread surface (1112) is L4, and L4 satisfies: 0.45mm≤L4≤0.975mm.

11. The battery case of claim 5, wherein, The weld width (300) is L3; The main body (110) has a first surface (113) facing away from the stepped groove (111), and the groove wall of the stepped groove (111) has a tread surface (1112) arranged parallel to the first surface (113). The distance between the first surface (113) and the tread surface (1112) is L4. The ratio of L3 to L4 is R2, and R2 satisfies: 0.75≤R2≤1.

12. The battery case of claim 5, wherein, The housing (200) includes a cylindrical sidewall (220), and the opening (210) is provided at one axial end of the cylindrical sidewall (220). The groove wall of the stepped groove (111) has a kick surface (1111), and the distance between the kick surface (1111) and the outer peripheral surface (221) of the cylindrical side wall (220) is L5, which satisfies: 1.2mm≤L5≤2mm.

13. The battery case of claim 5, wherein, The weld penetration depth of the weld (300) is L2; The housing (200) includes a cylindrical sidewall (220), and the opening (210) is provided at one axial end of the cylindrical sidewall (220); the groove wall of the stepped groove (111) has a kick surface (1111), and the distance between the kick surface (1111) and the outer peripheral surface (221) of the cylindrical sidewall (220) is L5; The ratio of L5 to L2 is R3, and R3 satisfies: 1≤R3≤2.

14. The battery case of claim 5, wherein, The main body (110) has a first surface (113) facing away from the stepped groove (111), and the groove wall of the stepped groove (111) has a tread surface (1112) parallel to the first surface (113).

15. The battery case of claim 14, wherein, The main body (110) also has a second surface (114) disposed opposite to the first surface (113), and the groove wall of the step groove (111) also has a kick surface (1111) connecting the tread (1112) and the second surface (114).

16. The battery case of claim 15, wherein, The tread (1112) is perpendicularly connected to the kick surface (1111).

17. The battery case of claim 5, wherein, The weld (300) and the stepped groove (111) each have overlapping areas on a target plane, which is perpendicular to the thickness direction of the battery cover (100).

18. An energy storage device, characterized by, Includes the battery casing as described in any one of claims 5-17.

19. A power supply system characterized by comprising: It includes electrical equipment and the energy storage device as described in claim 18, wherein the energy storage device supplies power to the electrical equipment.

Images