Housing, energy storage device and method for manufacturing thereof

Abstract

Embodiments of the present application provide a kind of shell, energy storage device and preparation method thereof.The shell includes fence, fence is enclosed cavity, and it has first side plate and second side plate, along the first direction, first side plate and second side plate are located in the side of shell;First side plate includes first end face, and second side plate includes second end face, along the second direction, first end face and second end face are opposite, and form assembly gap, assembly gap is communicated with cavity, the end of assembly gap away from cavity has outer port, and outer port is the welding position of first side plate and second side plate;Along the width direction of shell, the projection of at least one of first side plate and second side plate completely covers the projection of outer port;Wherein, the first direction and the second direction are perpendicular.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a casing, an energy storage device, and a method for preparing the same. Background Technology

[0002] With the development of energy storage technology, battery cells are continuously evolving towards larger capacity and larger size, and the size of the casing housing the cells is also increasing accordingly. The industry uses a combination of bending and forming with side laser welding for casing fabrication, along with a "cell first, then edge sealing" process to reduce manufacturing and assembly difficulties. However, in existing side laser welding solutions, the laser can easily penetrate into the casing through weld gaps or structural weaknesses, damaging the internal insulation film and the battery cells, leading to insulation failure and causing safety hazards and reliability issues. Summary of the Invention

[0003] This application provides a housing, an energy storage device, and a method for manufacturing the same, which can significantly reduce the risk of laser leakage during the side laser welding process, protect the insulating film and battery cell inside the housing, avoid insulation failure, and improve the safety and reliability of the energy storage device.

[0004] In a first aspect, embodiments of this application provide a housing. The housing includes a surrounding plate that forms a cavity, and has a first side plate and a second side plate, wherein the first side plate and the second side plate are both located on one side of the housing along a first direction; The first side plate includes a first end face, and the second side plate includes a second end face. Along the second direction, the first end face and the second end face are connected to each other and form an assembly gap. The assembly gap communicates with the cavity. The end of the assembly gap away from the cavity has an outer port. The outer port is the welding position of the first side plate and the second side plate. Along the width direction of the housing, the projection of at least one of the first side plate and the second side plate completely covers the projection of the outer port; wherein the first direction and the second direction are perpendicular to each other.

[0005] In one embodiment, both the first end face and the second end face are stepped surfaces.

[0006] In one embodiment, along the first direction, the ratio of the size of the projection of the first end face or the second end face in the second direction to the thickness of the enclosure is greater than or equal to 0.25 and less than or equal to 2.

[0007] In one embodiment, the first end face includes a first step side and two first step surfaces. The two first step surfaces are respectively connected to the inner surface and the inner surface of the first side plate. The projections of the two first step surfaces along the first direction do not overlap, and the projections of the two first step surfaces along the second direction do not overlap. The first step side connects the two first step surfaces and is set at an angle to the two first step surfaces. The second end face includes a second step side and two second step surfaces. The two second step surfaces are respectively connected to the inner surface and the inner surface of the second side plate. The projections of the two second step surfaces along the first direction do not overlap, and the projections of the two second step surfaces along the second direction do not overlap. The second step side connects the two second step surfaces and is set at an angle to the two second step surfaces. The two first step surfaces are respectively connected to the two second step surfaces, and the side surfaces of the first step and the side surfaces of the second step are connected to each other. In one embodiment, the side of the first step and the two first step surfaces are perpendicular to each other, and the side of the second step and the two second step surfaces are perpendicular to each other; The ratio of the sum of the widths of the first step side and the two first step surfaces to the thickness of the enclosure is greater than or equal to 1.5 and less than or equal to 4.5, and the ratio of the sum of the widths of the second step side and the two second step surfaces to the thickness of the enclosure is greater than or equal to 1.5 and less than or equal to 4.5.

[0008] In one embodiment, at least one of the two first step surfaces is arranged at an angle to the first direction, or the side of the first step is arranged at an angle to the second direction; At least one of the two second step surfaces is set at an angle to the first direction, or the side of the second step is set at an angle to the second direction.

[0009] In one embodiment, one of the first end face and the second end face is a convex surface, and the other is a concave surface.

[0010] In one embodiment, the enclosure further includes a recess, which is recessed on the outer surface of the enclosure and recessed towards the inner surface of the enclosure, and the recess communicates with the outer port. The recess includes a first recess and a second recess. The first recess is disposed on the first side plate, and the second recess is disposed on the second side plate. Along the second direction, the first recess and the second recess are disposed opposite to each other and are connected.

[0011] In one embodiment, the ratio of the depth of the recess to the thickness of the enclosure is greater than or equal to 0.25 and less than or equal to 0.5.

[0012] In one embodiment, the enclosure further includes a bottom opening located at one end in a third direction and communicating with the cavity; wherein the third direction is perpendicular to the first direction and the second direction; The housing also includes a bottom plate that covers the bottom opening and is connected to the surrounding panel.

[0013] Secondly, embodiments of this application provide an energy storage device. The energy storage device includes an end cap assembly, a battery cell, an insulating film, a protective film, and a housing. The insulating film covers the periphery and bottom of the battery cell and is housed together with the battery cell within the cavity. The end cap assembly is mounted on the top opening of the housing and connected to the housing. The protective film covers the outer side of the housing.

[0014] Thirdly, embodiments of this application provide a method for preparing an energy storage device. The method is used to prepare the energy storage device, comprising: An aluminum sheet is bent to form a enclosure, the enclosure forming a cavity and having a first side plate and a second side plate, the first side plate and the second side plate being arranged opposite to each other along a second direction; An insulating film is wrapped around the battery cell and inserted into the cavity together with the battery cell. The first side plate and the second side plate are then pressed together along the second direction. Laser welding is performed on the first side plate and the second side plate; The base plate and end cap assembly are welded to the two ends in a third direction, and together they seal the cavity. The protective film is wrapped around the outside of the base plate and the surrounding plate.

[0015] In related technologies, existing bent housings are susceptible to springback, straightness, and flatness issues, easily leading to gap fluctuations at the side seams and consequently a series of welding defects. During side laser welding, if the housing has issues such as side gap fluctuations, alignment deviations, uneven clamping, or welding trajectory misalignment, laser energy may penetrate into the housing through the side seams or weak points, posing a high risk of laser leakage. During side welding, the laser can easily penetrate into the housing through side seams or structural weaknesses, damaging the internal insulation film and battery cells, potentially causing insulation failure and resulting in safety hazards and reliability issues.

[0016] In this embodiment, a long strip of sheet material is bent sequentially to form a enclosure. One side of the enclosure includes a first side plate and a second side plate. The first end face of the first side plate and the second end face of the second side plate are joined together along a second direction to form an assembly gap. The assembly gap has an outer port communicating with the outside of the enclosure. The first and second end faces are designed with various mating surface forms, such as inclined surfaces, vertical step surfaces, inclined step surfaces, and concave-convex surfaces, so that the projection of at least one of the first and second side plates in the length direction of the energy storage device can completely block the outer port, thereby blocking the laser at the outer port and preventing the laser from directly reaching the inside of the enclosure, ensuring the performance of the components inside the enclosure (such as the battery cell and insulating film). Moreover, even if there is a certain gap fluctuation or alignment deviation between the first and second side plates, or if there is energy fluctuation during the welding process, at least one of the first and second side plates can prevent the laser from directly reaching the inside of the enclosure, thereby preventing laser damage to the battery cell and insulating film, preventing insulation failure, and improving the safety and reliability of the energy storage device. Attached Figure Description

[0017] 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.

[0018] 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 An exploded structural diagram of a portion of the energy storage device shown. Figure 4 for Figure 2 The diagram shows a partial structure of the energy storage device along the first cross-section of AA. Figure 5 for Figure 2 The diagram shows a partial structure of the energy storage device along a second cross-section of AA. Figure 6 for Figure 2 The diagram shows a partial structure of the energy storage device along the third cross section of AA. Figure 7 for Figure 2 The diagram shows a partial structure of the energy storage device along the fourth cross section of AA. Figure 8 for Figure 2 The diagram shows a partial structure of the energy storage device along the fifth cross section of AA; Figure 9 A flowchart illustrating a method for preparing an energy storage device according to an embodiment of this application.

[0019] 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, end cap assembly 300, battery cell 200, housing 100, top opening 101, top surface 201, bottom surface 202, side surface 203, first side surface 204, second side surface 205, enclosure 10, cavity 102, inner surface 11, outer surface 12, first side plate 13, first main board 14, third side plate 15, and so on. Main board 16, second side plate 17, first end face 131, second end face 171, outer port k, inner port j, first step side 133, first step surface 134, second step side 173, second step surface 174, pit 18, first pit 181, second pit 182, first surface 135, second surface 136, third surface 175, fourth surface 176, assembly gap D, sharp corner α, laser blocking amount s of first side plate 13 or second side plate 17, thickness t of enclosure 10, depth d of pit 18. Detailed Implementation

[0020] 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.

[0021] 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.

[0022] 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 that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] 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.

[0024] 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.

[0025] Current energy storage applications are quite widespread, including generation-side energy storage, grid-side energy storage, and consumption-side energy storage. 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-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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Optionally, the energy storage device 1000 may include, but is not limited to, individual batteries, or battery modules, battery packs, battery clusters, mobile power supplies, energy storage cabinets / energy storage containers, and other battery integrated systems composed of individual batteries.

[0032] Optionally, the single battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell 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 it.

[0033] It should be noted that 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, or other application forms. This application embodiment does not strictly limit the application form of the energy storage device 1000.

[0034] Please refer to the following: Figure 2 and Figure 3 , 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 shows an exploded structural diagram of a portion of the energy storage device. Among them, Figure 3 This only illustrates the structure of the battery cell and casing.

[0035] like Figure 2 As shown, this application provides an energy storage device 1000, which is a rectangular single-cell battery. For ease of description, the thickness direction of the energy storage device 1000 is defined as the second direction X (i.e., the X-axis direction), the width direction as the first direction Y (i.e., the Y-axis direction), and the length direction as the third direction Z (i.e., the Z-axis direction). The X-axis, Y-axis, and Z-axis directions are all perpendicular to each other.

[0036] 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 The description provided is based on the orientation shown. It does not constitute a limitation on the energy storage device 1000 in actual application scenarios. In some embodiments, the thickness direction, width direction, and length direction of the energy storage device 1000 are not limited to the first direction X, the second direction Y, and the third direction Z as defined above. This application does not impose any limitations in this regard.

[0037] like Figure 2 and Figure 3 As shown, the energy storage device 1000 includes an end cap assembly 300, a battery cell 200, a housing 100, a protective film (not shown), and an insulating film (not shown). The housing 100 has a top opening 101. The battery cell 200 and the insulating film are both housed within the housing 100. The end cap assembly 300 is mounted on one side of the battery cell 200 along its length (i.e., the Z-axis direction) and seals it within the top opening 101 of the housing 100 to isolate the internal and external environments of the energy storage device 1000. The insulating film covers the periphery of the battery cell 200 and the surface away from the end cap assembly 300 to insulate the battery cell 200 from the housing 100, preventing short circuits and protecting the battery cell 200. The protective film covers the outside of the housing 100 to protect and insulate it. In this embodiment, the housing 100 is a rectangular aluminum shell. The insulating film and protective film can be, but are not limited to, Mylar film.

[0038] The battery cell 200 includes a top surface 201, a bottom surface 202, and a side surface 203. The top surface 201 and the bottom surface 202 are arranged opposite to each other along the length direction of the battery cell 200. The side surface 203 is connected to the top surface 201 and the bottom surface 202. The side surface 203 includes two first side surfaces 204 and two second side surfaces 205. The two first side surfaces 204 are arranged opposite to each other along the width direction (i.e., the Y-axis direction) of the battery cell 200. The two second side surfaces 205 are arranged opposite to each other along the thickness direction (i.e., the X-axis direction) of the battery cell 200. Each first side surface 204 is connected to two second side surfaces 205. In this embodiment, the area of ​​the first side surface 204 is smaller than the area of ​​the second side surface 205.

[0039] The housing 100 includes a surrounding plate 10 and a bottom plate (not shown). The surrounding plate 10 forms a cavity 102, a top opening 101, and a bottom opening (not shown). The top opening 101 and the bottom opening are positioned opposite each other and spaced apart along the length direction (i.e., the Z-axis direction) of the surrounding plate 10, and both the top opening 101 and the bottom opening communicate with the cavity 102. The bottom plate covers the bottom opening of the surrounding plate 10 and is connected to the surrounding plate 10 to seal the bottom opening. In this embodiment, the surrounding plate 10 and the bottom plate are formed separately. The surrounding plate 10 can be a long strip of aluminum sheet bent into a rectangular cylindrical structure. The bottom plate is a rectangular aluminum sheet.

[0040] The enclosure 10 includes an inner surface 11 and an outer surface 12. The inner surface 11 and the outer surface 12 are arranged facing away from each other along a direction perpendicular to the length direction of the enclosure 10 (i.e., perpendicular to the third direction Y). The inner surface 11 faces the cavity 102, and the outer surface 12 faces away from the cavity 102.

[0041] The enclosure 10 also includes a first side plate 13, a first main plate 14, a second side plate 17, a second main plate 16, and a third side plate 15. The first side plate 13, first main plate 14, third side plate 15, second main plate 16, and second side plate 17 are connected sequentially to form a cavity 102. The first side plate 13 and the first main plate 14 are arranged at an angle. The first main plate 14 and the third side plate 15 are arranged at an angle. The third side plate 15 and the second main plate 16 are arranged at an angle. The second main plate 16 and the second side plate 17 are arranged at an angle. The first main plate 14 and the second main plate 16 are positioned opposite each other and spaced apart along the thickness direction of the enclosure 10. The third side plate 15 is located on one side of the width direction of the enclosure 10. The first side plate 13 and the second side plate 17 are located on the other side of the width direction of the enclosure 10, and are connected opposite each other along the thickness direction of the enclosure 10.

[0042] In this embodiment, the first side plate 13, the first main plate 14, the third side plate 15, the second main plate 16, and the second side plate 17 are integral structures, formed by sequentially bending long strips of aluminum sheet. The thicknesses of the first side plate 13, the first main plate 14, the third side plate 15, the second main plate 16, and the second side plate 17 are approximately the same, all being t, which is also the thickness of the surrounding plate 10. The first side plate 13 and the second side plate 17 are butted together and connected and fixed by laser welding.

[0043] The first side plate 13 and the second side plate 17 are joined together, and the two mating surfaces form an assembly gap D. The assembly gap D includes an outer port k and an inner port j. Along the width direction of the enclosure plate 10, the outer port k and the inner port j are spaced apart and located at opposite ends of the extension direction of the assembly gap D. The outer port k connects the assembly gap D and the outer side of the enclosure plate 10. The inner port j connects the assembly gap D and the inner side of the enclosure plate 10. It can be understood that the outer port k is located on the outer surface 12 of the enclosure plate 10. The inner port j is located on the inner surface 11 of the enclosure plate 10. The outer port k is the welding position of the first side plate 13 and the second side plate 17. Along the width direction of the enclosure 10, the projection of the outer port k is completely located within the projection of at least one of the first side plate 13 and the second side plate 17, so that the first side plate 13 or the second side plate 17 can completely block the laser during the welding process, preventing the laser from passing directly from the assembly gap D to the inner side of the enclosure 10, reducing laser burns to the insulating film and the battery cell 200, avoiding the failure of the insulating function of the insulating film, and improving the safety and reliability of the energy storage device 1000.

[0044] The structural form of assembly gap D will be described below with reference to specific embodiments.

[0045] Please see Figure 4 , Figure 4 for Figure 2 The diagram shows a partial structure of the energy storage device along a first cross-section of AA. Among them, Figure 4 The diagram only shows the cross-section of the casing and the battery cell, and can also be regarded as a first embodiment of the casing and a cross-sectional view of the battery cell.

[0046] In this embodiment, the first side plate 13 and the second side plate 17 are joined together in a beveled manner.

[0047] Specifically, the first side plate 13 includes a first end face 131. Along the thickness direction of the surrounding plate 10, the first end face 131 is located away from the first main plate 14. The first end face 131 connects to the inner surface 11 and the outer surface 12 of the first side plate 13, and is inclined relative to the inner surface 11 and the outer surface 12 of the first side plate 13. A first included angle exists between the first end face 131 and the inner surface 11 of the first side plate 13, and a second included angle exists between the first end face 131 and the outer surface 12 of the first side plate 13. It can be understood that the first end face 131 is a plane that forms an angle with the first direction Y, i.e., an inclined plane. In this embodiment, the first included angle is an obtuse angle, and the second included angle is an acute angle. Along the thickness direction of the first side plate 13 (i.e., the Y-axis direction), the projection of the first end face 131 onto the outer surface 12 of the first side plate 13 in the X-axis direction has a dimension s, and the ratio of s to the thickness t of the first side plate 13 is the tangent of the second included angle. The second included angle is greater than or equal to 30° and less than or equal to 60°, which ensures the rationality of the structure of the first side plate 13, so as to avoid the first side plate 13 being difficult to process and having low structural strength due to the second included angle being too small, and also to avoid the high docking accuracy requirements with the second side plate 17 due to the second included angle being too large.

[0048] The second side plate 17 includes a second end face 171. Along the thickness direction of the surrounding plate 10, the second end face 171 is located away from the second main plate 16. The second end face 171 connects to the inner surface 11 and the outer surface 12 of the second side plate 17 and is inclined relative to the inner surface 11 and the outer surface 12 of the second side plate 17. A third included angle exists between the second end face 171 and the inner surface 11 of the second side plate 17, and a fourth included angle exists between the second end face 171 and the outer surface 12 of the second side plate 17. It can be understood that the second end face 171 is a plane that forms an angle with the first direction Y, i.e., an inclined plane. In this embodiment, the third included angle is an acute angle, and the fourth included angle is an obtuse angle. Along the thickness direction of the second side plate 17 (i.e., the Y-axis direction), the projection of the second end face 171 onto the inner surface 11 of the second side plate 17 in the X-axis direction has a dimension s, and the ratio of s to the thickness t of the second side plate 17 is the tangent of the third included angle. The third included angle is greater than or equal to 30° and less than or equal to 60°, which ensures the rationality of the structure of the second side plate 17, so as to avoid the second side plate 17 being difficult to process and having low structural strength due to the third included angle being too small, and also to avoid the high docking accuracy requirements with the first side plate 13 due to the third included angle being too large.

[0049] It is understood that in this embodiment, the second included angle and the third included angle are equal, and can be regarded as the sharp angles α of the first side plate 13 and the second side plate 17, respectively, that is, the first end face 131 and the second end face 171 are parallel. For example, the angles α of the sharp angles α of the first side plate 13 and the second side plate 17 are both greater than or equal to 30° and less than or equal to 60°.

[0050] In this embodiment, as Figure 4As shown, the enclosure 10 is formed by bending a long strip of aluminum sheet. An insulating film covers the side surface 203 and bottom surface 202 of the battery cell 200 and is assembled with the enclosure 10 along with the battery cell 200. The top surface 201 of the battery cell 200 is opposite to and spaced apart from the top opening 101 of the enclosure 10. The bottom surface 202 of the battery cell 200 is opposite to and spaced apart from the bottom opening of the enclosure 10. One of the two first side surfaces 204 of the battery cell 200 is opposite to and spaced apart from the third side plate 15, and the other first side surface 204 is opposite to and spaced apart from the first side plate 13 and the second side plate 17. The two second side surfaces 205 of the battery cell 200 are opposite to and spaced apart from the first main plate 14 and the second main plate 16, respectively.

[0051] The first side plate 13 and the second side plate 17 are pressed together along the thickness direction of the surrounding plate 10, so that the first end face 131 of the first side plate 13 and the second end face 171 of the second side plate 17 come into contact with each other and form an assembly gap D.

[0052] On the outer side of the enclosure 10, at the outer port k of the assembly gap D, the first side plate 13 and the second side plate 17 are laser welded to form a connector (not shown in the figure), thereby fixing the first side plate 13 and the second side plate 17 together. The connector completely covers the outer port k to ensure the weld sealing and weld strength of the first side plate 13 and the second side plate 17. The connector is the joint formed by welding the first side plate 13 and the second side plate 17, i.e., the weld seam.

[0053] In this embodiment, the first end face 131 faces the inner side of the enclosure 10, and the second end face 171 faces the outer side of the enclosure 10. Along the width direction of the enclosure 10, the outer port k and the inner port j are staggered, and the projection of the outer port k is completely located within the projection of the second side plate 17, that is, the second side plate 17 completely blocks the outer port k. When the first side plate 13 and the second side plate 17 are laser welded along the first direction Y, the second side plate 17 can effectively block the laser along the first direction Y from the outer side of the enclosure 10, preventing the laser along the first direction Y from passing directly from the assembly gap D to the inner side of the enclosure 10, thereby reducing the risk of laser burning the insulating film and the battery cell 200, preventing the insulation function of the insulating film from failing, and improving the safety and reliability of the energy storage device 1000.

[0054] The projection of the second end face 171 in the Y-axis direction onto the X-axis dimension is s, which can be understood as the amount of laser blocking by the second side plate 17 being s. The ratio of the blocking amount to the thickness t of the enclosure 10 is equal to the tangent of the sharp angle α (i.e., tan(α)). The sharp angle α of the second side plate 17 is greater than or equal to 30° and less than or equal to 60°, ensuring that the second side plate 17 has sufficient blocking length in the second direction X to effectively block lasers along the first direction Y. Moreover, even if there are manufacturing tolerances in the first side plate 13 and the second side plate 17 themselves, or assembly tolerances between the first side plate 13 and the second side plate 17, causing fluctuations in the dimension of the outer port k in the X-axis direction, the second side plate 17 can still effectively block lasers entering from the outer port k, reducing the risk of lasers entering the inner side of the enclosure 10 and damaging the insulating film and the battery cell 200, improving the alignment tolerance of the first side plate 13 and the second side plate 17, and reducing the processing and assembly difficulty of the enclosure 10.

[0055] Both the first end face 131 and the second end face 171 are inclined surfaces, and they are parallel to each other and completely mated together. Compared to the mating of two surfaces that are relatively parallel along the first direction Y, the mating of two planes that are set at an angle to the first direction Y can increase the effective mating area of ​​the first side plate 13 and the second side plate 17, resulting in a deeper weld penetration between the first side plate 13 and the second side plate 17, a smoother stress distribution at the joint, and improved weld strength of the first side plate 13 and the second side plate 17, thereby improving the structural strength of the enclosure plate 10. Moreover, the welding energy can be gradually conducted and evenly distributed along the inclined surface, which lengthens the conduction path of the welding energy, reduces the impact of high welding temperature on the insulating film and the battery cell 200, and makes the welding energy distribution smoother, reducing local accumulation of welding energy, ensuring the welding quality of the first side plate 13 and the second side plate 17, and ensuring the welding seal.

[0056] A bottom plate is fitted over the bottom opening of the enclosure 10 and welded to the enclosure 10 to seal the bottom opening. An end cap assembly 300 is fitted over the top opening 101 of the enclosure 10 and welded to the enclosure 10 to seal the top opening 101. A protective film covers the outer surface 12 of the enclosure 10 and the surface of the bottom plate facing away from the top opening 101.

[0057] In this embodiment, the first side plate 13 and the second side plate 17 can be formed into the first end face 131 and the second end face 171 respectively by stamping. The stamping method allows for one-time forming of the first side plate 13 and the second side plate 17 using a mold, suitable for mass production of the enclosure 10. Alternatively, the first side plate 13 and the second side plate 17 can also be formed into the first end face 131 and the second end face 171 respectively by turning. The turning method involves multiple cuts with a cutting tool, suitable for small-batch production of the enclosure 10. This application does not impose any limitations on this method.

[0058] In some embodiments, the first side plate 13 completely blocks the outer port k, and the dimension s of the projection of the first end face 131 in the Y-axis direction onto the X-axis direction can be regarded as the amount of laser blocking by the first side plate 13, which is s. Specifically, the first included angle is an acute angle, and the second included angle is an obtuse angle. At the same time, the third included angle is an obtuse angle, and the fourth included angle is an acute angle. The first included angle and the fourth included angle are the apex angles α of the first side plate 13 and the second side plate 17, respectively.

[0059] In some embodiments, the housing 100 may not have a bottom plate, and the energy storage device 1000 includes two end cap assemblies 300, which respectively cover and seal the top opening 101 and the bottom opening of the enclosure 10. This application does not limit this.

[0060] Please see Figure 5 , Figure 5 for Figure 2 The diagram shows a partial structure of the energy storage device along a second cross-section of AA. Among them, Figure 5 The diagram only shows the cross-section of the casing and the battery cell; it can also be viewed as a second embodiment of the casing and a cross-sectional view of the battery cell.

[0061] Unlike the structure of the housing 100 in the first embodiment described above, in this embodiment, the first side plate 13 and the second side plate 17 are joined together in the form of a vertical stepped surface.

[0062] Specifically, the first end face 131 of the first side plate 13 is a vertical stepped surface. The first end face 131 includes a first stepped side face 133 and two first stepped surfaces 134. Both first stepped surfaces 134 are parallel to the width direction of the surrounding plate 10 and are arranged in a stepped manner along the thickness direction of the surrounding plate 10. One of the first stepped surfaces 134 is connected to the inner surface 11 of the first side plate 13, and the other first stepped surface 134 is connected to the outer surface 12 of the first side plate 13. Along the thickness direction of the surrounding plate 10, the first stepped side face 133 is located between the two first stepped surfaces 134 and is perpendicularly connected to the two first stepped surfaces 134. That is, along the first direction Y, the projections of the two first stepped surfaces 134 do not overlap. Along the second direction X, the projections of the two first stepped surfaces 134 do not overlap. In this embodiment, along the thickness direction of the surrounding plate 10, the first stepped surface 134 near the outer surface 12 is further away from the first main plate 14 than the first stepped surface 134 near the inner surface 11. The first step side 133 and the inner surface 11 of the first side plate 13 face the same direction.

[0063] Along the width direction of the enclosure 10, the projection of the first step side surface 133 (i.e., the projection of the first end face 131) in the X-axis direction has a dimension of s. The sum of the dimensions of the two first step surfaces 134 in the Y-axis direction and the dimension of the first step side surface 133 in the X-axis direction is w. For example, the ratio of s to the thickness t of the first side plate 13 is greater than or equal to 0.25 and less than or equal to 2, and the ratio of w to the thickness t of the first side plate 13 is greater than or equal to 1.5 and less than or equal to 4.5.

[0064] The second end face 171 of the second side plate 17 is a vertical stepped surface. The second end face 171 includes a second stepped side surface 173 and two second stepped surfaces 174. Both second stepped surfaces 174 are parallel to the width direction of the surrounding plate 10 and are arranged in a stepped manner along the thickness direction of the surrounding plate 10. One second stepped surface 174 is connected to the inner surface 11 of the second side plate 17, and the other second stepped surface 174 is connected to the outer surface 12 of the second side plate 17. Along the thickness direction of the surrounding plate 10, the second stepped side surface 173 is located between the two second stepped surfaces 174 and is perpendicularly connected to the two second stepped surfaces 174. That is, along the first direction Y, the projections of the two second stepped surfaces 174 do not overlap. Along the second direction X, the projections of the two second stepped surfaces 174 do not overlap. In this embodiment, along the thickness direction of the surrounding plate 10, the second stepped surface 174 connected to the outer surface 12 of the second side plate 17 is closer to the second main plate 16 than the second stepped surface 174 connected to the inner surface 11 of the second side plate 17. The second step side 173 and the outer surface 12 of the second side plate 17 face the same direction.

[0065] Along the width direction of the enclosure 10, the projection of the second step side surface 173 (i.e., the projection of the second end face 171) in the X-axis direction has a dimension of s. The sum of the dimensions of the two second step surfaces 174 in the Y-axis direction and the dimensions of the second step side surface 173 in the X-axis direction is w. For example, the ratio of s to the thickness t of the second side plate 17 is greater than or equal to 0.25 and less than or equal to 2, and the ratio of w to the thickness t of the second side plate 17 is greater than or equal to 1.5 and less than or equal to 4.5.

[0066] In this embodiment, the first end face 131 and the second end face 171 are aligned to form an assembly gap D. Specifically, along the thickness direction of the surrounding plate 10, the two first step surfaces 134 are aligned with the two second step surfaces 174 respectively. Along the width direction of the surrounding plate 10, the first step side surface 133 is aligned with the second step side surface 173. The first step side surface 133 faces the inner side of the surrounding plate 10, and the second step side surface 173 faces the outer side of the surrounding plate 10. Along the width direction of the surrounding plate 10, the outer port k and the inner port j are staggered, and the projection of the outer port k is completely located within the projection of the second side plate 17, that is, the second side plate 17 completely blocks the outer port k. When laser welding is performed on the first side plate 13 and the second side plate 17, the second side plate 17 can effectively block the laser from the outside of the enclosure 10, preventing the laser from passing directly from the assembly gap D to the inside of the enclosure 10, thereby reducing the risk of laser burning the insulating film and the battery cell 200, preventing the insulation function of the insulating film from failing, and improving the safety and reliability of the energy storage device 1000.

[0067] The projection of the second step side 173 (i.e., the second end face 171) in the Y-axis direction onto the X-axis dimension is s. This can be understood as the amount of laser blocking by the second side plate 17 being s. The ratio of the blocking amount to the thickness t of the enclosure 10 is greater than or equal to 0.25 and less than or equal to 2. Even if there are manufacturing tolerances in the first side plate 13 and the second side plate 17, or assembly tolerances between the first side plate 13 and the second side plate 17, causing fluctuations in the dimension of the outer port k in the X-axis direction, the second side plate 17 can still effectively block the laser entering from the outer port k, reducing the risk of the laser entering the inner side of the enclosure 10 and damaging the insulating film and the battery cell 200. This improves the alignment tolerance of the first side plate 13 and the second side plate 17 and reduces the processing and assembly difficulty of the enclosure 10.

[0068] Both the first end face 131 and the second end face 171 are vertical stepped surfaces. The two first stepped surfaces 134 and the first stepped side surface 133 of the first end face 131 (or the two second stepped surfaces 174 and the second stepped side surface 173 of the second end face 171) constitute the effective contact surface of the first end face 131 and the second end face 171, that is, the sum of the widths of the effective contact surfaces of the first end face 131 and the second end face 171 is w. It can also be understood that the sum of the dimensions of the first end face 131 in the first direction Y and the second direction X is w, and at the same time, the sum of the dimensions of the second end face 171 in the first direction Y and the second direction X is also w. The ratio of w to the thickness t of the enclosure plate 10 is greater than or equal to 1.5 and less than or equal to 4.5. Compared with the butt joint of two relatively parallel surfaces along the first direction Y, the vertical step surface form of the butt joint increases the effective contact area of ​​the first side plate 13 and the second side plate 17, resulting in a deeper weld penetration, a more gradual stress distribution at the joint, and improved weld strength of the first side plate 13 and the second side plate 17, thereby improving the structural strength of the enclosure plate 10.

[0069] The uneven design of the vertical step surface allows the laser to weld the first side plate 13 and the second side plate 17 within a multi-angle range. Furthermore, the guiding effect of the vertical step surface facilitates the relative pressing of the first side plate 13 and the second side plate 17, achieving reliable positioning between them and controllable assembly gap D, thus improving assembly alignment stability. Specifically, when the first side plate 13 and the second side plate 17 are pressed together, the first end face 131 and the second end face 171 form reliable radial and axial constraints, effectively suppressing warping, deformation, or opening / closing of the first side plate 13 and the second side plate 17. This ensures that the first side plate 13 and the second side plate 17 always maintain a tight fit and a uniform assembly gap D, thereby guaranteeing the stability of the welding process and reducing welding discontinuities caused by warping or uneven assembly gap D. The radial constraint is achieved through the cooperation of the first step side face 133 and the second step side face 173. The axial constraint is achieved through the cooperation of two first step surfaces 134 and two second step surfaces 174.

[0070] In some embodiments, the first side plate 13 completely blocks the outer port k, and the amount of laser blocking by the first side plate 13 is the dimension s of the projection of the first end face 131 in the Y-axis direction onto the X-axis direction. Specifically, along the thickness direction of the enclosure plate 10, the first step surface 134 near the inner surface 11 is further away from the first main plate 14 than the first step surface 134 near the outer surface 12. The first step side 133 faces the outer side of the enclosure plate 10. Meanwhile, along the thickness direction of the enclosure plate 10, the second step surface 174 near the inner surface 11 is closer to the second main plate 16 than the second step surface 174 near the outer surface 12. The second step side 173 faces the inner side of the enclosure plate 10.

[0071] In some embodiments, there are two or more first step surfaces 134 and two or more first step side surfaces 133, with the number of first step surfaces 134 exceeding the number of first step side surfaces 133 by one. The plurality of first step surfaces 134 are parallel to the width direction of the enclosure 10 and are arranged in a stepped manner. A first step side surface 133 is provided between two adjacent first step surfaces 134, and each surface is perpendicularly connected to this first step side surface 133. Similarly, there are two or more second step surfaces 174 and two or more second step side surfaces 173, with the number of second step surfaces 174 exceeding the number of second step side surfaces 173 by one. The plurality of second step surfaces 174 are parallel to the width direction of the enclosure 10 and are arranged in a stepped manner. A second step side surface 173 is provided between two adjacent second step surfaces 174, and each surface is perpendicularly connected to this second step side surface 173.

[0072] It should be noted that the structure of this embodiment is the same as that of the first embodiment described above, and will not be repeated here.

[0073] Please see Figure 6 , Figure 6 for Figure 2 The diagram shows a partial structure of the energy storage device along a third cross-section of AA. Among them, Figure 6 The diagram only shows the cross-section of the casing and the battery cell; it can also be viewed as a third embodiment of the casing and a cross-sectional view of the battery cell.

[0074] Unlike the structure of the housing 100 in the second embodiment described above, in this embodiment, the enclosure 10 further includes a recess 18. The recess 18 is recessed into the outer surface 12 of the enclosure 10 and recessed towards the inner surface 11 of the enclosure 10. A portion of the recess 18 is located on the first side plate 13, and another portion is located on the second side plate 17. The recess 18 is used to accommodate the connecting body between the first side plate 13 and the second side plate 17, preventing the connecting body from protruding from the outer surface 12, ensuring the flatness of the outer surface 12 of the enclosure 10, and facilitating the subsequent application of a protective film.

[0075] In this embodiment, the width of the recess 18 is greater than or equal to the width of the connector between the first side plate 13 and the second side plate 17, and the depth d of the recess 18 depends on the maximum height of the connector protruding from the outer surface 12 that the protective film can accept. For example, the width of the recess 18 is approximately equal to the width of the connector between the first side plate 13 and the second side plate 17, and the ratio of the depth d of the recess 18 to the thickness t of the surrounding plate 10 is greater than or equal to 0.25 and less than or equal to 0.5.

[0076] Specifically, the first side plate 13 also includes a first recess 181. The first recess 181 is recessed on the outer surface 12 of the first side plate 13 and is recessed towards the inner surface 11 of the first side plate 13. The first recess 181 penetrates the first step surface 134 near the outer side of the surrounding plate 10.

[0077] The second side plate 17 also includes a second recess 182. The second recess 182 is recessed on the outer surface 12 of the second side plate 17 and is recessed towards the inner surface 11 of the second side plate 17. The second recess 182 penetrates the second step surface 174 near the outer side of the surrounding plate 10.

[0078] In this embodiment, the first side plate 13 and the second side plate 17 are joined together to form an assembly gap D. Along the thickness direction of the surrounding plate 10, the first recess 181 and the second recess 182 are oppositely arranged and connected, forming a recess 18 together. The recess 18 is connected to the assembly gap D through the outer port k. At the outer port k of the surrounding plate 10, the first side plate 13 and the second side plate 17 are laser welded. The welded connector is accommodated in the recess 18, preventing the connector from protruding from the outer surface 12 of the surrounding plate 10, making the outer surface 12 flatter. When the protective film is subsequently wrapped around the outer side of the shell 100, this prevents the protective film from being pushed up by the connector, causing uneven adhesion, wrinkling, stress concentration, and damage, thus improving the consistency of the film appearance and meeting the requirements of the shell 100 outer wrapping process. Moreover, the recess 18 can also increase the welding bonding area and the depth of the weld, ensuring the appearance quality while making the welding of the first side plate 13 and the second side plate 17 more secure.

[0079] It should be noted that the contents of this embodiment are the same as those of the second embodiment described above, and will not be repeated here.

[0080] Please see Figure 7 , Figure 7 for Figure 2 The diagram shows a partial structure of the energy storage device along the fourth cross-section of AA. Among them, Figure 7 The diagram only shows the cross-section of the casing and the battery cell; it can also be viewed as a fourth embodiment of the casing and a cross-sectional view of the battery cell.

[0081] Unlike the structure of the housing 100 in the second embodiment described above, in this embodiment, the first side plate 13 and the second side plate 17 are joined together in the form of a stepped surface. That is, the first end face 131 of the first side plate 13 and the second end face 171 of the second side plate 17 are both stepped surfaces.

[0082] Specifically, at least one of the two first step surfaces 134 of the first side plate 13 is a plane at an angle to the first direction Y, and the first step side surface 133 is a plane at an angle to the second direction X, and the first step side surface 133 is set at an angle to the two first step surfaces 134. Simultaneously, at least one of the two second step surfaces 174 is a plane at an angle to the first direction Y, and the second step side surface 173 is a plane at an angle to the second direction X, and the second step side surface 173 is set at an angle to the two second step surfaces 174. The first end surface 131 should be opposite to and fitted to the second end surface 171. The angles between the first step side surface 133 and the two first step surfaces 134, and the angles between the second step side surface 173 and the two second step surfaces 174, are less than 180°. Furthermore, the angle between the first step side surface 133 and at least one first step surface 134 is not equal to 90°, and the angle between the second step side surface 173 and at least one second step surface 174 is not equal to 90°.

[0083] In this embodiment, the first stepped surface 134 of the inner surface 11 connecting the first side plate 13 is inclined relative to the inner surface 11 and the first stepped side surface 133, that is, the first stepped surface 134 is set at an angle (not equal to 90°) with the inner surface 11 and the first stepped side surface 133 of the first side plate 13. The second stepped surface 174 of the inner surface 11 connecting the second side plate 17 is inclined relative to the inner surface 11 and the second stepped side surface 173, that is, the second stepped surface 174 is set at an angle (not equal to 90°) with the inner surface 11 and the second stepped side surface 173 of the second side plate 17.

[0084] The first side plate 13 and the second side plate 17 are aligned. The first stepped surface 134 of the inner surface 11 of the first side plate 13 is aligned with and fits against the second stepped surface 174 of the inner surface 11 of the second side plate 17. The first stepped surface 134 of the outer surface 12 of the first side plate 13 is aligned with and fits against the second stepped surface 174 of the outer surface 12 of the second side plate 17. The first stepped side surface 133 and the second stepped side surface 173 are aligned with and fit against each other. Along the width direction of the enclosure 10, the projection of the outer port k is completely located within the projection of the second side plate 17, that is, the second side plate 17 completely covers the outer port k. When laser welding is performed on the first side plate 13 and the second side plate 17, the second side plate 17 can effectively block the laser from the outside of the enclosure 10, preventing the laser from passing directly from the assembly gap D between the first side plate 13 and the second side plate 17 to the inside of the enclosure 10. This reduces the risk of laser burning the insulating film and the battery cell 200, prevents the insulation function of the insulating film from failing, and improves the safety and reliability of the energy storage device 1000.

[0085] In this embodiment, the first side plate 13 and the second side plate 17 are joined together in the form of a sloping stepped surface, which not only further improves the guiding assembly effect, but also increases the effective contact area, further increases the weld penetration between the first side plate 13 and the second side plate 17, and further smooths the stress distribution at the connection body. Moreover, it allows the welding energy to be gradually conducted along the curved path, further lengthening the welding energy conduction path and more effectively reducing the impact of high welding temperature on the insulating film and the battery cell 200.

[0086] In some embodiments, where high manufacturing precision can be achieved, the first stepped surface 134 connecting the outer surface 12 of the first side plate 13 is inclined relative to the outer surface 12 and the first stepped side surface 133, that is, the first stepped surface 134 is set at an angle (not equal to 90°) with the outer surface 12 and the first stepped side surface 133 of the first side plate 13. The second stepped surface 174 connecting the outer surface 12 of the second side plate 17 is inclined relative to the outer surface 12 and the second stepped side surface 173, that is, the second stepped surface 174 is set at an angle (not equal to 90°) with the outer surface 12 and the second stepped side surface 173 of the second side plate 17.

[0087] Certainly, in some embodiments, the first side plate 13 and the second side plate 17 may also be provided with the pits 18 described above to ensure the flatness of the outer surface 12 of the surrounding plate 10, which facilitates the subsequent wrapping of the protective film.

[0088] It should be noted that the contents of the present embodiment that have the same structure as the above second embodiment will not be repeated herein.

[0089] Please refer to Figure 8 , Figure 8 it is Figure 2 a fifth cross-sectional schematic view taken along A-A of a partial structure of the energy storage device as shown. Wherein, Figure 8 only the cross-section of the surrounding plate of the housing and the battery cell is schematically illustrated, which can also be regarded as a cross-sectional view of the fifth embodiment of the housing and the battery cell.

[0090] Different from the structure of the housing 100 in the first embodiment described above, in the present embodiment, the first side plate 13 and the second side plate 17 are butted in a concave-convex surface form. One of the first end surface 131 and the second end surface 171 is a convex surface, and the other is a concave surface. The convex surface may be generally a "convex"-shaped surface, an arc-shaped convex surface, or the like. The concave surface may be generally a "concave"-shaped surface, an arc-shaped concave surface, or the like.

[0091] Specifically, the first end surface 131 comprises a first surface 135 and a second surface 136. The first surface 135 is connected to the inner surface 11 and the outer surface 12 of the first side plate 13. The second surface 136 is connected to the first surface 135 and protrudes from the first surface 135 in the second direction X away from the first main plate 14. The first surface 135 may be a plane forming an included angle with the first direction Y, or may be a plane parallel to the first direction Y. The second surface 136 may be, but is not limited to, a rectangular convex surface, a triangular convex surface, an arc-shaped convex surface, or the like.

[0092] The second end surface 171 comprises a third surface 175 and a fourth surface 176. The third surface 175 is connected to the inner surface 11 and the outer surface 12 of the second side plate 17. The fourth surface 176 is connected to the third surface 175 and is recessed in the second direction X toward the second main plate 16. The third surface 175 may be a plane forming an included angle with the first direction Y, or may be a plane parallel to the first direction Y. The fourth surface 176 may be, but is not limited to, a rectangular concave surface, a triangular concave surface, an arc-shaped concave surface, or the like.

[0093] For example, as shown in Figure 8 , the first surface 135 and the third surface 175 are both planes parallel to the first direction Y, that is, both are parallel to the length direction of the surrounding plate 10. The second surface 135 is generally a rectangular convex surface, and the fourth surface 176 is generally a rectangular concave surface.

[0094] In this embodiment, the first end face 131 is a "convex"-shaped face, and the second end face 171 is a "concave"-shaped face. The first side plate 13 and the second side plate 17 are butted to form an assembly gap D. Specifically, along the thickness direction of the surrounding plate 10, the first face 135 is butted against the third face 175, and the second face 136 is butted against the fourth face 176. It can be understood that the first side plate 13 and the second side plate 17 form a mortise-tenon joint, wherein the first side plate 13 is provided with a tenon, and the second side plate 17 is provided with a mortise groove. When the first side plate 13 and the second side plate 17 are butted, the tenon is accommodated in the mortise groove, so that clamping limiting of the first side plate 13 and the second side plate 17 is realized, which effectively ensures the butting accuracy of the first side plate 13 and the second side plate 17 and the uniformity of the assembly gap D, and improves the assembly alignment stability.

[0095] Along the width direction of the surrounding plate 10, the projection of the outer port k is completely located within the projection of the second face 136, that is, the first side plate 13 completely shields the outer port k. When laser welding is performed on the first side plate 13 and the second side plate 17, the first side plate 13 can well block the laser outside the surrounding plate 10, preventing the laser from passing directly to the inner side of the surrounding plate 10, thereby reducing the risk of laser burning the insulating film and the battery cell 200, avoiding the failure of the insulating function of the insulating film, and improving the safety and reliability of the energy storage device 1000.

[0096] In some embodiments, the first end face 131 is a concave face (such as a "concave"-shaped face), and the second end face 171 is a convex face (such as a "convex"-shaped face). The second face 136 of the first end face 131 is recessed toward the first main plate 14 along the second direction X, and the fourth face 176 of the second end face 171 protrudes from the third face 175 along the second direction X in a direction away from the second main plate 16. That is, the first side plate 13 is provided with a mortise groove, and the second side plate 17 is provided with a tenon. When the first side plate 13 and the second side plate 17 are butted, the tenon of the second side plate 17 is accommodated in the mortise groove of the first side plate 13. Along the width direction of the surrounding plate 10, the projection of the outer port k is completely located within the projection of the fourth face 176, that is, the second side plate 17 completely shields the outer port k. When laser welding is performed on the first side plate 13 and the second side plate 17, the second side plate 17 can well block the laser outside the surrounding plate 10, preventing the laser from passing directly to the inner side of the surrounding plate 10, thereby reducing the risk of laser burning the insulating film and the battery cell 200, avoiding the failure of the insulating function of the insulating film, and improving the safety and reliability of the energy storage device 1000.

[0097] It should be noted that the structural contents of this embodiment are the same as those of the first embodiment described above, and will not be repeated here. Furthermore, the form of the mating surfaces of the first side plate 13 and the second side plate 17 is not limited to the forms illustrated in the above embodiments; it can also be a combination of the above embodiments, such as a concave-convex surface mating joint with a recessed pit 18, etc., as long as at least one of the first side plate 13 and the second side plate 17 can completely block the outer port k, so that the laser from the outside of the enclosure 10 cannot directly reach the inside of the housing 100. This application does not impose strict limitations in this regard. The following is a brief description of the preparation method of the energy storage device 1000, which mainly describes how the housing 100 is formed and how the housing 100 is fitted with the battery cell 200.

[0098] Please see Figure 9 , Figure 9 A flowchart illustrating a method for fabricating an energy storage device provided in this application embodiment, wherein the method for fabricating the energy storage device includes: Step S1: The aluminum sheet is bent to form a surrounding plate 10. The surrounding plate 10 forms a cavity 102 and has a first side plate 13 and a second side plate 17. The first side plate 13 and the second side plate 17 are arranged opposite each other along the second direction X.

[0099] Step S2: Wrap the insulating film around the battery cell 200 and insert it into the cavity 102 together with the battery cell 200. Then, press the first side plate 13 and the second side plate 17 together along the second direction X.

[0100] Step S3: Laser welding is performed on the first side plate 13 and the second side plate 17.

[0101] Step S4: The base plate and end cap assembly 300 are welded to both ends of the perimeter plate 10 along its length, and together they seal the cavity 102.

[0102] Step S5: Cover the outside of the base plate and the surrounding plate 10 with a protective film.

[0103] In step S3, the first side plate 13 and the second side plate 17 can be spot-welded for positioning before continuous or segmented welding to ensure welding quality and sealing. Furthermore, based on existing bending and forming combined with side laser welding for edge sealing, this embodiment is compatible with the existing sequence of "bending first, then inserting the battery cell into the casing, and finally welding the side edges for edge sealing." The mating surfaces of the first side plate 13 and the second side plate 17 are structurally optimized. The solution to welding risks (such as laser leakage) relies not only on equipment parameters and fixture control but also on the structural design of the casing 100 itself, reducing modification costs and facilitating large-scale application. Moreover, this embodiment improves welding reliability and packageability through integration, ensuring the stability of the welding trajectory on the sides of the casing 100 and the airtightness consistency of the casing 100.

[0104] In related technologies, as the capacity and size of battery cells gradually increase, the size of the casing housing the cells also increases accordingly. When using traditional stamping and stretching processes to manufacture large-size casings, the manufacturing difficulty, assembly difficulty, and production cost significantly increase. Therefore, the industry has shifted to a solution combining bending forming with side laser welding for casing fabrication, along with a "casing first, edge sealing" process to reduce manufacturing and assembly difficulties, improve operability, and increase production yield. However, existing bent casings are susceptible to springback, straightness, and flatness issues, easily leading to gap fluctuations at the side seams, resulting in a series of welding defects. During side laser welding, if the casing has problems such as side gap fluctuations, alignment deviations, uneven clamping, or welding trajectory misalignment, laser energy may penetrate into the casing through the side seams or weak points, posing a high risk of laser leakage. During side welding, the laser can easily penetrate into the casing through side seams or structural weaknesses, damaging the internal insulation film and battery cells, leading to insulation failure and causing safety hazards and reliability issues.

[0105] In this embodiment, a long strip of sheet metal is sequentially bent to form a first side plate 13, a first main plate 14, a third side plate 15, a second main plate 16, and a second side plate 17. The first side plate 13 and the second side plate 17 are joined along the thickness direction of the enclosure 10, forming an assembly gap D and an outer port k and an inner port j communicating with the assembly gap D. The outer port k is located on the outer surface 12 of the enclosure 10. The inner port j is located on the inner surface 11 of the enclosure 10. Along the width direction of the enclosure 10, the projection of at least one of the first side plate 13 and the second side plate 17 completely covers the projection of the outer port k, thus blocking the laser. Even if there is a certain gap fluctuation or alignment deviation between the first side plate 13 and the second side plate 17, or if there are energy fluctuations during the welding process, the laser can be prevented from directly penetrating to the inside of the enclosure 10, thereby preventing laser damage to the battery cell 200 and the insulating film, avoiding insulation failure, and improving the safety and reliability of the energy storage device 1000.

[0106] The first side plate 13 and the second side plate 17 can adopt one or more of the following forms: beveled face, vertical step face, beveled step face, concave and convex face. This not only reduces the sensitivity of the first side plate 13 and the second side plate 17 to assembly tolerance and fixture clamping consistency, making the first side plate 13 and the second side plate 17 more stable, the assembly gap D more controllable, and the welding effect better, but also reduces the probability of welding defects from the source and improves the airtightness consistency of the welded side plate 10 through the coordinated control of the structure and forming process of the enclosure plate 10. Furthermore, it provides a replicable path for bending side welding of different specifications of enclosure plates 10 to adapt to various welding equipment and production line capabilities.

[0107] 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. A housing, characterized in that, The housing includes a surrounding plate that forms a cavity and has a first side plate and a second side plate. Along a first direction, the first side plate and the second side plate are both located on one side of the housing. The first side plate includes a first end face, and the second side plate includes a second end face. Along the second direction, the first end face and the second end face are connected to each other and form an assembly gap. The assembly gap communicates with the cavity. The end of the assembly gap away from the cavity has an outer port. The outer port is the welding position of the first side plate and the second side plate. Along the first direction, the projection of at least one of the first side plate and the second side plate completely covers the projection of the outer port; wherein the first direction and the second direction are perpendicular to each other.

2. The housing according to claim 1, characterized in that, Both the first end face and the second end face are stepped surfaces.

3. The housing according to claim 2, characterized in that, Along the first direction, the ratio of the dimensions of the projections of the first end face and the second end face in the second direction to the thickness of the enclosure is greater than or equal to 0.25 and less than or equal to 2.

4. The housing according to claim 2, characterized in that, The first end face includes a first step side and two first step surfaces. The two first step surfaces are respectively connected to the outer surface and the inner surface of the first side plate. The projections of the two first step surfaces along the first direction do not overlap, and the projections of the two first step surfaces along the second direction do not overlap. The first step side connects the two first step surfaces and is set at an angle to the two first step surfaces. The second end face includes a second step side and two second step surfaces. The two second step surfaces are respectively connected to the outer surface and the inner surface of the second side plate. The projections of the two second step surfaces along the first direction do not overlap, and the projections of the two second step surfaces along the second direction do not overlap. The second step side connects the two second step surfaces and is set at an angle to the two second step sides. The two first step surfaces are respectively connected to the two second step surfaces, and the side surfaces of the first step and the side surfaces of the second step are connected to each other.

5. The housing according to claim 4, characterized in that, The side of the first step is perpendicular to the two surfaces of the first step, and the side of the second step is perpendicular to the two surfaces of the second step. The ratio of the sum of the widths of the first step side and the two first step surfaces to the thickness of the enclosure is greater than or equal to 1.5 and less than or equal to 4.5, and the ratio of the sum of the widths of the second step side and the two second step surfaces to the thickness of the enclosure is greater than or equal to 1.5 and less than or equal to 4.

5.

6. The housing according to claim 4, characterized in that, At least one of the two first step surfaces is set at an angle to the first direction, or the side of the first step is set at an angle to the second direction; At least one of the two second step surfaces is set at an angle to the first direction, or the side of the second step is set at an angle to the second direction.

7. The housing according to claim 1, characterized in that, One of the first end face and the second end face is a convex surface, and the other is a concave surface.

8. The housing according to any one of claims 1-7, characterized in that, The enclosure also includes a recess, which is recessed on the outer surface of the enclosure and recessed into the inner surface of the enclosure. The recess is connected to the outer port. The recess includes a first recess and a second recess. The first recess is disposed on the first side plate, and the second recess is disposed on the second side plate. Along the second direction, the first recess and the second recess are disposed opposite to each other and are connected.

9. The housing according to claim 8, characterized in that, The ratio of the depth of the pit to the thickness of the enclosure is greater than or equal to 0.25 and less than or equal to 0.

5.

10. The housing according to any one of claims 1-7, characterized in that, The enclosure also includes a bottom opening located at one end in a third direction and communicating with the cavity; wherein, the third direction is perpendicular to the first direction and the second direction; The housing also includes a bottom plate that covers the bottom opening and is connected to the surrounding panel.

11. An energy storage device, characterized in that, The energy storage device includes an end cap assembly, a battery cell, an insulating film, a protective film, and a housing as described in any one of claims 1-10. The insulating film covers the periphery and bottom of the battery cell and is housed together with the battery cell in the cavity. The end cap assembly is mounted on the top opening of the housing and connected to the housing. The protective film covers the outside of the housing.

12. A method for preparing an energy storage device, characterized in that, The method is used to prepare the energy storage device as described in claim 11, comprising: An aluminum sheet is bent to form a enclosure, the enclosure forming a cavity and having a first side plate and a second side plate, the first side plate and the second side plate being arranged opposite to each other along a second direction; An insulating film is wrapped around the battery cell and inserted into the cavity together with the battery cell. The first side plate and the second side plate are then pressed together along the second direction. Laser welding is performed on the first side plate and the second side plate; The base plate and end cap assembly are welded to the two ends in a third direction, and together they seal the cavity. The protective film is wrapped around the outside of the base plate and the surrounding plate.

Images