Battery cell, battery device, and electric device

Abstract

The utility model discloses a battery monomer, battery device and electric device, the battery monomer includes the casing, and the casing includes: bottom shell, and bottom shell defines the cavity that one side opens in the first direction, top cover, top cover covers the open side of cavity, and includes the cover and the flanging, and the flanging is connected in the circumferential of cover and extends as annular along the circumferential of cover, and the flanging is overlapped with the side wall of bottom shell in the first direction, and is connected through the first welding mark at the overlapped position, in the laminated direction of side wall and flanging, the first welding mark is welded into shape from the outside of casing to the cavity, and the melting point of one of side wall and flanging away from the cavity is set and is less than the melting point of the other one close to the cavity. According to the battery monomer of the utility model, can make the welding position connection more closely, improve the sealing effect of welding position, improve the welding efficiency and welding yield between bottom shell and top cover, satisfy the sealing performance requirement of casing, improve the safety performance of battery monomer.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Technology

[0002] With the rapid iteration of consumer electronics products, and following the EU's new regulations on removable and replaceable batteries for handheld electronic devices, the demand for hard-shell batteries in consumer electronics has continued to grow, and their application scope is constantly expanding. Against this backdrop, consumers have placed higher demands on the safety of hard-shell batteries, paying particular attention to risks such as leakage and explosion that could lead to battery failure. This has imposed more stringent standards on the manufacturing process of hard-shell batteries. In the field of square lithium-ion battery casing sealing design, especially for hard-shell batteries used in digital terminals, the surge in market demand has brought numerous challenges to the manufacturing process. Welding is a critical step, directly determining the overall performance of the battery and its qualification for production. Currently, the industry commonly uses conventional welding techniques such as seam welding. However, this process requires extremely high dimensional accuracy control, which significantly reduces production efficiency in actual production. Furthermore, if any critical dimension is not controlled to the standard, it can easily lead to welding defects, such as weld explosions or leaks. This not only increases production costs but also further exacerbates the problem of low production efficiency, making it difficult to meet the current demands for large-scale, high-quality production of hard-shell batteries. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a battery cell that can improve the welding efficiency and yield between the bottom shell and the top cover, meet the shell sealing performance requirements, and enhance the safety performance of the battery cell.

[0004] This utility model also proposes a battery device having the above-mentioned battery cells.

[0005] This utility model also proposes an electrical device having the above-mentioned battery cell or battery device.

[0006] According to a first aspect of the present invention, a battery cell includes a housing, the housing comprising: a bottom shell defining a cavity open on one side in a first direction; a top cover covering the open side of the cavity, and including a cover body and a flange, the flange being connected to the periphery of the cover body and extending in a ring shape along the circumference of the cover body, the flange overlapping with a sidewall of the bottom shell in the first direction and connected at the overlapping position by a first weld mark, wherein, in the overlapping direction of the sidewall and the flange, the first weld mark is welded from the outside of the housing toward the cavity, and the melting point of the sidewall and the flange located away from the cavity is less than the melting point of the other located closer to the cavity.

[0007] According to the present invention, the battery cell is connected at the overlap position by a first weld mark by the side wall of the bottom shell and the folded edge of the top cover. The first weld mark is formed from the outside to the inside in a direction perpendicular to the first direction, and the melting point of the outer material at the welding position is lower than that of the inner material. This not only makes the connection at the welding position tighter and improves the sealing effect of the welding position, but also avoids over-welding and avoids the risk of leakage at the welding position of the shell. This improves the welding efficiency and welding yield between the bottom shell and the top cover, meets the shell sealing performance requirements, and enhances the safety performance of the battery cell.

[0008] In some embodiments of this utility model, the difference between the melting point of the sidewall and the melting point of the folded edge is 200℃-300℃.

[0009] In some embodiments of this utility model, one of the bottom shell and the top cover is made of stainless steel, and the other is made of titanium or titanium alloy.

[0010] In some embodiments of this utility model, in the first direction, the height of the folded edge is 0.25mm-0.7mm, and / or the overlap length between the folded edge and the sidewall is 0.15mm-0.5mm.

[0011] In some embodiments of this utility model, one end of the folded edge is connected to the cover body, and the other end extends toward the bottom shell along the first direction and extends to the side surface of the side wall opposite to the cavity.

[0012] In some embodiments of this utility model, the wall thickness of the folded edge is less than or equal to the wall thickness of the side wall, and both the wall thickness of the side wall and the wall thickness of the folded edge are 0.05mm-0.25mm.

[0013] In some embodiments of this utility model, the wall thickness of the sidewall is 0.1mm-0.25mm; and / or, the wall thickness of the folded edge is 0.1mm-0.2mm.

[0014] In some embodiments of this utility model, the top cover and the bottom shell are interference-fitted in the stacking direction of the folded edge and the side wall.

[0015] In some embodiments of this utility model, the folded edge is connected to the cover body by an arc bend, and the hardness of the top cover is greater than that of the bottom shell. In the first direction, the end of the side wall facing the cover body is bent toward the cavity to fit the arc inner wall where the folded edge is connected to the cover body.

[0016] In some embodiments of this utility model, in the first direction, the height of the bent portion at one end of the sidewall is 0.05mm-0.1mm, and / or, in the overlapping direction of the sidewall and the folded edge, the height of the bent portion at one end of the sidewall protruding from the inner wall surface of the remaining portion of the sidewall is 0.01mm-0.05mm.

[0017] In some embodiments of this utility model, the first direction is the thickness direction of the housing of the battery cell, and the cover is the housing wall with the largest area among all the housing walls.

[0018] The battery device according to the second aspect of the present invention includes a battery cell according to the first aspect of the present invention.

[0019] According to the present invention, the battery device improves the overall performance of the battery device by providing the battery cells described in the first aspect.

[0020] The electrical device according to the second aspect of the present invention includes a battery cell according to the first aspect of the present invention or a battery device according to the second aspect of the present invention.

[0021] According to the present invention, by providing the battery cell of the first aspect or the battery device of the second aspect, the overall performance of the electrical device is improved.

[0022] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a battery cell according to an embodiment of the present utility model; Figure 2 This is a cross-sectional view of a battery cell according to an embodiment of the present utility model; Figure 3 yes Figure 2 A partial enlarged view of the battery cell shown; Figure 4This is a partially enlarged cross-sectional view of a battery cell according to other embodiments of the present invention; Figure 5 This is a schematic diagram of the structure of a battery cell casing that is welded at an angle with a welding head; Figure 6 yes Figure 5 A partially enlarged cross-sectional view of the welding head and battery cell shown; Figure 7 This is a schematic diagram of the structure of a welding head vertically welding the casing of a battery cell; Figure 8 yes Figure 7 A partially enlarged view of the cross-sectional view of the welding head and battery cell shown.

[0024] Figure label: 100. Battery cell; 10. Shell; 101. Cavity; 11. Bottom shell; 111. Side walls; 12. Top cover; 121. Cover body; 122. Folded edge; 20. Pole post; 30. Sealing pin; 200. Welding head. Detailed Implementation

[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0026] The following is for reference. Figures 1-8 A battery cell 100 according to a first aspect embodiment of the present invention is described.

[0027] like Figure 1 As shown, the battery cell 100 according to a first aspect embodiment of the present invention includes a housing 10, the housing 10 including: a bottom shell 11 and a top cover 12, the bottom shell 11 defining a first direction (e.g., Figure 1 A cavity 101 is open on one side (shown in the vertical direction); a top cover 12 covers the open side of the cavity 101, and the top cover 12 includes a cover body 121 and a flange 122, the flange 122 is connected to the periphery of the cover body 121 and extends in a ring shape along the circumference of the cover body 121, the flange 122 and the side wall 111 of the bottom shell 11 are connected in a first direction (e.g., in the vertical direction). Figure 1The two sides are overlapped in the vertical direction shown in the figure and connected by a first weld at the overlap position. In the overlapping direction of the side wall 111 and the folded edge 122, the first weld is formed by welding from the outside of the housing 10 toward the cavity 101. The melting point of the side wall 111 and the folded edge 122 that are far away from the cavity 101 is less than the melting point of the other one that is close to the cavity 101.

[0028] like Figure 1 and Figure 2 As shown, the battery cell 100 includes a housing 10, a battery cell, a terminal post 20, and an electrolyte. A cavity 101 is defined inside the housing 10. The battery cell is disposed in the cavity 101 of the housing 10, and the electrolyte is also filled in the cavity 101 of the housing 10. The terminal post 20 includes a positive electrode and a negative electrode. The terminal post 20 is disposed on the housing 10 and includes a terminal post body, a metal pressure ring, and sealant. The terminal post body is sealed to the housing 10 by the sealant. The metal pressure ring is arranged on the outside of the housing 10 and connected to the terminal post 20 body. An injection hole is also formed on the housing 10. The electrolyte is injected into the housing 10 through the injection hole. A sealing pin 30 is also provided on the housing 10 to seal the injection hole.

[0029] like Figure 2 and Figure 3 As shown, the housing 10 includes a bottom shell 11 and a top cover 12. The bottom shell 11 is a square box shape with an open top. The top cover 12 is sealed on the top of the bottom shell 11. The top cover 12 is sealed to the bottom shell 11 to ensure the sealing performance of the housing 10 and prevent leakage of electrolyte and other substances inside the housing 10.

[0030] The top cover 12 includes a cover body 121 and a flange 122. The cover body 121 and the flange 122 are integrally formed. The cover body 121 is a rectangular plate shape. The flange 122 is connected to the periphery of the cover body 121 and extends in a ring shape along the circumference of the cover body 121. The top cover 12 is sealed to the bottom shell 11 through the flange 122. Specifically, the flange 122 is welded to the bottom shell 11, and a first weld mark is formed at the welding position of the flange 122 and the bottom shell 11. The first weld mark is formed by welding the outer surface of the shell 10 perpendicular to the first direction toward the side where the cavity 101 inside the shell 10 is located. This facilitates the welding operation between the bottom shell 11 and the flange 122.

[0031] When the top cover 12 is placed on top of the bottom shell 11, the flange 122 can be arranged on the outer side of the bottom shell 11 away from the cavity 101, or the flange 122 can be arranged on the side of the bottom shell 11 facing the cavity 101. With the side of the shell 10 away from the cavity 101 as the outer side and the side of the shell 10 facing the cavity 101 as the inner side, in the thickness direction of the side wall 111 of the bottom shell 11, when the flange 122 is arranged on the outer side of the side wall 111, the melting point of the flange 122 is lower than the melting point of the side wall 111; when the flange 122 is arranged on the inner side of the side wall 111, the melting point of the side wall 111 is lower than the melting point of the flange 122.

[0032] In this embodiment, during the welding process between the bottom shell 11 and the top cover 12 of the battery cell 100, the outer layer material (e.g., Figure 3 The folded edge 122 of the top cover 12 shown has a lower melting point, which allows the material on the outer side to be fully welded, resulting in a tighter weld and improved sealing. Meanwhile, the inner layer material (e.g., Figure 3 The sidewall 111 of the bottom shell 11 shown has a higher melting point, which can ensure that over-welding does not occur when welding from the outside to the inside, so as not to cause the inner layer material to be welded through, thereby avoiding the risk of leakage at the welding position of the shell 10. As a result, the welding efficiency and welding yield between the bottom shell 11 and the top cover 12 can be improved, the sealing performance requirements of the shell 10 can be met, the safety performance of the shell 10 can be improved, and the safety performance of the battery cell 100 can be improved.

[0033] Furthermore, it should be noted that the first weld mark between the bottom shell 11 and the top cover 12 in this embodiment is formed by welding from the outside to the inside in the stacking direction of the folded edge 122 and the side wall 111. Compared with the weld seam process, this embodiment forms the first weld mark by through welding, which can reduce the assembly tolerance requirements between the bottom shell 11 and the top cover 12, reduce the welding difficulty between the bottom shell 11 and the top cover 12, and reduce the risk of weld explosion and missed weld.

[0034] According to the embodiment of the present invention, the battery cell 100 is connected at the overlap position by a first weld mark by the side wall 111 of the bottom shell 11 and the folded edge 122 of the top cover 12 through the first weld mark. The first weld mark is formed from the outside to the inside in a direction perpendicular to the first direction, and the melting point of the outer material at the welding position is lower than that of the inner material. Therefore, the connection at the welding position can be made tighter, the sealing effect at the welding position can be improved, and over-welding can be avoided, thus avoiding the risk of leakage at the welding position of the shell 10. This improves the welding efficiency and welding yield between the bottom shell 11 and the top cover 12, meets the sealing performance requirements of the shell 10, and improves the safety performance of the battery cell 100.

[0035] In some embodiments of this invention, the difference between the melting point of the sidewall 111 and the melting point of the folded edge 122 is 200℃-400℃, or the difference between the melting point of the bottom shell 11 and the melting point of the top cover 12 is 200℃-400℃. Further, the difference between the melting point of the sidewall 111 and the melting point of the folded edge 122 can be 200℃-300℃, or the difference between the melting point of the bottom shell 11 and the melting point of the top cover 12 is 200℃-300℃. For example, the difference between the melting point temperature of the sidewall 111 and the melting point temperature of the folded edge 122 can be 200℃, 220℃, 240℃, 260℃, 280℃, 300℃, or 320℃.

[0036] In this embodiment, by setting the melting point temperature difference between the sidewall 111 and the folded edge 122 to 200℃-300℃, the outer layer material can rapidly melt to form a flowing molten pool during welding of the sidewall 111 and the folded edge 122, fully filling the overlap gap between them. This improves the sealing performance between the sidewall 111 and the folded edge 122, while allowing the inner material to partially melt. This not only achieves a strong fusion with the outer layer material, improving connection reliability, but also avoids excessive melting of the inner layer material, reducing the risk of thinning or deformation of the inner layer structure and the risk of leakage due to melting through the inner layer material, thus improving welding quality and efficiency. Furthermore, the 200℃-300℃ higher melting point of the inner layer material also reduces heat conduction to the interior of the battery cell 100 during the welding process, minimizing thermal damage to the internal structures such as the battery cell.

[0037] In some embodiments of this utility model, one of the bottom shell 11 and the top cover 12 is made of stainless steel, and the other is made of titanium or titanium alloy. For example, when the folded edge 122 of the top cover 12 is located on the outer side of the side wall 111 of the bottom shell 11, the top cover 12 is made of stainless steel, and the bottom shell 11 is made of titanium or titanium alloy; when the folded edge 122 of the top cover 12 is located on the inner side of the side wall 111 of the bottom shell 11, the top cover 12 is made of titanium or titanium alloy, and the bottom shell 11 is made of stainless steel.

[0038] In some embodiments, the top cover 12 is made of stainless steel, which improves the structural strength and deformation resistance of the top cover 12, enhances its corrosion resistance, and extends its service life. The bottom shell 11 is made of titanium or titanium alloy, which not only improves its structural strength and impact resistance, enhances its corrosion resistance, and extends its service life, but also reduces its weight, achieving the lightweight requirement of the battery cell 100 and increasing its energy density.

[0039] In this embodiment, one of the bottom shell 11 and the top cover 12 is made of stainless steel, and the other is made of titanium or titanium alloy. Since the melting point of stainless steel is approximately 1375℃-1400℃, and the melting point of titanium or titanium alloy is approximately 1668℃, during welding, the stainless steel easily melts to form a molten pool, filling the gap between the stainless steel and titanium components. Simultaneously, the surface layer of the titanium or titanium alloy component can partially melt, thus creating a strong fusion between the stainless steel and titanium, improving the connection strength. Furthermore, the stainless steel, titanium, or titanium alloy components are resistant to electrolyte corrosion and have high strength, thereby improving the overall structural stability and reliability of the shell 10 and extending its service life.

[0040] In some embodiments of this utility model, such as Figure 3 As shown, in the first direction (e.g.) Figure 3 In the vertical direction (as shown), the height H1 of the folded edge 122 is 0.2mm-1.5mm. For example, the height H1 of the folded edge 122 in the vertical direction can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm.

[0041] Furthermore, in the first direction (e.g.) Figure 3 In the vertical direction (as shown), the height H1 of the folded edge 122 is 0.25mm-0.7mm. For example, the height H1 of the folded edge 122 in the vertical direction can be 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm or 0.7mm.

[0042] In this embodiment, by setting the height H1 of the folded edge 122 to 0.25mm-0.7mm, the folded edge 122 has sufficient height to overlap and connect with the side wall 111 of the bottom shell 11, ensuring an effective connection between the bottom shell 11 and the top cover 12 and guaranteeing the connection strength between them. On the other hand, it avoids the folded edge 122 being too large, preventing interference between the folded edge 122 and other structures arranged on the side wall 111 of the bottom shell 11, such as the pole post 20 or the injection hole. It also reduces the amount of material used and the overlap gap between the folded edge 122 and the side wall 111, ensuring that the molten material during welding can effectively fill the overlap gap, avoiding defects such as incomplete welding and missing welding, and improving the welding quality.

[0043] In some embodiments of this utility model, such as Figure 3 As shown, in the first direction (e.g.) Figure 3In the vertical direction shown, the overlap length H2 between the folded edge 122 and the side wall 111 is greater than or equal to 0.15 mm and less than or equal to the height H1 of the folded edge 122. Further, as... Figure 3 As shown, in the first direction (e.g.) Figure 3 In the vertical direction (as shown), the overlap length H2 between the folded edge 122 and the side wall 111 is 0.15mm-0.5mm. For example, the overlap length H2 between the folded edge 122 and the side wall 111 in the vertical direction can be 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm or 0.5mm.

[0044] In this embodiment, by ensuring that the overlap length H2 between the folded edge 122 and the side wall 111 is greater than or equal to 0.15 mm and less than or equal to 0.5 mm, sufficient overlap contact area can be provided between the folded edge 122 and the side wall 111, thereby improving the structural strength and reliability of the welded connection, reducing the risk of cracking at the weld position of the housing 10, avoiding excessive increase in the overall thickness of the housing 10, reducing the material usage and space occupation of the housing 10, and increasing the energy density of the battery cell 100.

[0045] In some embodiments of this utility model, such as Figure 3 As shown, in the stacking direction of the folded edge 122 and the side wall 111, the folded edge 122 is arranged on the side of the side wall 111 facing away from the cavity 101. In the first direction, the distance between the end edge of the bottom shell 11 facing the cover 121 and the side surface of the cover 121 facing the cavity 101 is a first distance H3, and the first distance H3 is less than or equal to the overlap length H2 between the folded edge 122 and the side wall 111. In this embodiment, by forming a first distance H3 between the upper end edge of the bottom shell 11 and the lower surface of the cover 121, when the periphery of the top cover 12 is bent to form the folded edge 122, the interference between the bending positions of the bottom shell 11 and the top cover 12 can be reduced. At the same time, by making the first distance H3 less than the overlap length H2, the overall height of the folded edge 122 can be reduced, avoiding excessive space occupation by the folded edge 122, and making the structure of the shell 10 more compact.

[0046] Furthermore, the first spacing H3 is greater than or equal to 0.15 mm, and even further, the first spacing H3 is greater than or equal to 0.2 mm. For example, the first spacing H3 can be 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, or 0.5 mm. This allows for a sufficient gap to be reserved between the top cover 12 and the bottom shell 11, facilitating the processing and forming of the top cover 12, reducing interference at the bending positions of the bottom shell 11 and the top cover 12, and facilitating the assembly of the top cover 12 and the bottom shell 11, thereby improving assembly efficiency.

[0047] In some embodiments of this utility model, such as Figure 3, Figure 4 , Figure 6 and Figure 8 As shown, one end of the folded edge 122 (for example) Figure 3 The upper end of the folded edge 122 shown is connected to the cover 121, and the other end of the folded edge 122 (e.g.) Figure 3 The lower end of the folded edge 122 shown extends along the first direction toward the bottom shell 11 and extends to the side surface of the side wall 111 opposite to the cavity 101. That is, the folded edge 122 of the top cover 12 surrounds the side wall 111 opposite to the cavity 101, and during welding, the first weld mark is formed from the outer surface of the folded edge 122 toward the inner surface of the side wall 111. As a result, the folded edge 122 can avoid occupying the space inside the bottom shell 11, thereby increasing the space for the cell and electrolyte, and improving the energy density and charge-discharge cycle performance of the battery cell 100.

[0048] In some embodiments of this utility model, such as Figure 3 and Figure 4 As shown, the wall thickness W2 of the flange 122 is less than or equal to the wall thickness W1 of the side wall 111. The thinner wall thickness W2 of the flange 122 allows it to be heated more quickly to its melting temperature during welding, forming a uniform molten pool, reducing welding difficulty, improving welding efficiency, and preventing situations where the flange 122 cannot be fully penetrated. The thicker wall thickness W1 of the side wall 111 ensures its structural strength, reduces the risk of deformation due to heat during welding, and improves the structural stability and strength of the shell 10. Furthermore, the fact that the wall thickness W2 of the flange 122 is less than or equal to the wall thickness W1 of the side wall 111 allows for control over the material usage of the flange 122, achieving cost control and lightweighting while ensuring welding strength and sealing performance, thus avoiding material waste.

[0049] In some embodiments of this utility model, such as Figure 3 and Figure 4 As shown, the wall thickness W1 of the sidewall 111 is 0.05mm-0.25mm. For example, the wall thickness W1 of the sidewall 111 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, or 0.25mm. In this embodiment, by making the wall thickness W1 of the sidewall 111 greater than or equal to 0.05mm, the structural strength of the sidewall 111 can be guaranteed, the impact resistance of the sidewall 111 can be improved, and the risk of the sidewall 111 being melted through can be reduced. By making the wall thickness W1 of the sidewall 111 less than or equal to 0.25mm, the amount of material used in the sidewall 111 can be reduced, thereby reducing the weight of the shell 10.

[0050] In some embodiments of this utility model, such as Figure 3 and Figure 4As shown, the wall thickness W2 of the folded edge 122 is 0.05mm-0.25mm. For example, the wall thickness W2 of the folded edge 122 can be 0.05mm, 0.1mm, 0.15mm, 0.2mm, or 0.25mm. In this embodiment, by making the wall thickness W2 of the folded edge 122 greater than or equal to 0.05mm, the structural strength of the folded edge 122 can be guaranteed, and the impact resistance of the folded edge 122 can be improved. By making the wall thickness W2 of the folded edge 122 less than or equal to 0.25mm, the material usage of the folded edge 122 can be reduced, the weight of the shell 10 can be reduced, and the folded edge 122 can be easily melted to fill the lap gap between the folded edge 122 and the side wall 111, thereby improving welding efficiency and sealing performance.

[0051] In some embodiments of this utility model, such as Figure 3 and Figure 4 As shown, the wall thickness W1 of sidewall 111 is 0.1mm-0.25mm; for example, the wall thickness W1 of sidewall 111 can be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, or 0.24mm. This further ensures the structural strength of sidewall 111, improves its impact resistance, reduces the risk of sidewall 111 being melted through, and guarantees the sealing performance of the welded positions.

[0052] In some embodiments of this utility model, such as Figure 3 and Figure 4 As shown, the wall thickness W2 of the flange 122 can be 0.1mm-0.2mm. For example, the wall thickness W2 of the flange 122 can be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, or 0.2mm. This further ensures the structural strength of the flange 122, improves its impact resistance, and also enhances its melting efficiency, as well as the welding efficiency and sealing performance between the flange 122 and the sidewall 111.

[0053] In some embodiments of this utility model, such as Figure 3 and Figure 4 As shown, in the stacking direction of the folded edge 122 and the sidewall 111 (e.g. Figure 3 and Figure 4 In the left-right direction shown, the top cover 12 and the bottom shell 11 are interference-fitted.

[0054] This embodiment uses an interference fit between the top cover 12 and the bottom shell 11 at the overlap position. This not only reduces or even eliminates the overlap gap between the folded edge 122 and the side wall 111, preventing molten pool loss during welding and resulting in weld defects, but also enhances the stability of the pre-assembly between the bottom shell 11 and the top cover 12, preventing misalignment between the bottom shell 11 and the top cover 12 during subsequent welding connections, thus improving assembly accuracy and reliability. In addition, the interference fit can form a double seal with the first weld mark, further reducing the risk of electrolyte leakage and ensuring the safe use of the battery cell 100.

[0055] In some embodiments of this utility model, such as Figure 4 As shown, the folded edge 122 is connected to the cover 121 by an arc bend, and the hardness of the top cover 12 is greater than that of the bottom shell 11. In the first direction, the end of the side wall 111 facing the cover 121 is bent toward the cavity 101 to fit the arc inner wall of the folded edge 122 connected to the cover 121.

[0056] During the pre-assembly of the top cover 12 and the housing 10, the top cover 12 is first fastened to the top of the bottom housing 11, so that the annular folded edge 122 is fitted on the outside of the open end of the bottom housing 11. Then the top cover 12 is pressed down. Since the hardness of the top cover 12 is greater than that of the bottom housing 11, the open end of the bottom housing 11 will deform during the process of the top cover 12 and the bottom housing 11 being closed. It will bend slightly toward the inside of the cavity 101 and fit against the inner arc wall surface where the folded edge 122 is connected to the cover body 121.

[0057] In this embodiment, by making the hardness of the top cover 12 greater than that of the bottom shell 11, the top cover 12 can be guaranteed not to deform during the pre-assembly of the top cover 12 and the bottom shell 11, while the open end of the bottom shell 11 deforms and the bent part fits against the arc inner wall of the folded edge 122. Thus, a tight fit between the bottom shell 11 and the top cover 12 can be achieved without tooling positioning, simplifying the pre-assembly process. At the same time, the bent part of the open end of the bottom shell 11 fits against the arc inner wall of the folded edge 122, which can eliminate the overlap gap between the folded edge 122 and the side wall 111, preventing impurities from entering the interior of the shell 10. It can also prevent the loss of the molten pool during welding, which would cause defects in the first weld mark, further reducing the risk of electrolyte leakage.

[0058] In some embodiments of this utility model, such as Figure 3 and Figure 4As shown, the folded edge 122 includes a vertical segment and an arc segment. The vertical segment extends in a straight line along a first direction, and the arc segment connects the vertical segment and the cover 121. In the first direction, the arc segment is an arc plate-shaped section extending along an arc line protruding towards the side opposite to the cavity 101. The surface of the arc segment facing away from the cavity 101 is an outer arc surface, and the surface of the arc segment facing into the cavity 101 is an inner arc surface. The radii R1 of the outer arc surface and R2 of the inner arc surface satisfy: 0.2mm ≤ R2 ≤ R1 ≤ 0.5mm. Therefore, by making the folded edge 122 and the cover 121 arc-connected, stress concentration at the connection point can be avoided, improving the service life of the top cover 12. Furthermore, setting the radii R1 of the outer arc surface and R2 of the inner arc surface to 0.2mm-0.5mm facilitates the processing of the top cover 12 and improves processing efficiency.

[0059] In some examples, the sidewall 111 of the bottom shell 11 may overlap only with the vertical section, thereby simplifying the overlap structure and improving pre-assembly efficiency. In other examples, the sidewall 111 of the bottom shell 11 may also overlap with both the vertical section and a portion of the arc section. This further extends the length of the overlap portion, improving the pre-assembly stability and reliability between the bottom shell 11 and the top cover 12.

[0060] In some embodiments of this utility model, such as Figure 4 As shown, in the first direction (e.g.) Figure 4 On the vertical direction shown), one end of the sidewall 111 (e.g.) Figure 4 The height H4 of the bent portion (at the upper end of the side wall 111 shown) is 0.05mm-0.1mm. For example, if the upper end of the side wall 111 is bent, the height H4 of the bent portion can be 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, or 0.1mm. Therefore, by making the height H4 of the bent portion greater than or equal to 0.05mm, a tight fit between the bottom shell 11 and the top cover 12 can be achieved, improving pre-assembly stability. By making the height H4 of the bent portion less than or equal to 0.1mm, the height of the bent portion can be controlled, reducing pre-assembly difficulty and improving pre-assembly efficiency.

[0061] In some embodiments of this utility model, such as Figure 4 As shown, in the stacking direction of the sidewall 111 and the folded edge 122 (e.g. Figure 4 On the left and right directions shown), one end of the sidewall 111 (e.g. Figure 4The height L1 of the bent portion (at the upper end of the sidewall 111 shown) protruding from the inner wall surface of the rest of the sidewall 111 is 0.01mm-0.05mm. For example, the upper end of the sidewall 111 is bent, and in the thickness direction of the fold 122, the height of the bent portion protruding from the inner wall surface of the rest of the sidewall 111 toward the cavity 101 is a first height, which can be 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm.

[0062] In this embodiment, by ensuring that the height L1 of the bent portion protruding from the inner wall surface of the remaining part of the side wall 111 is greater than or equal to 0.01mm, it is possible to ensure that the bent portion deforms, thereby achieving a tight fit between the bottom shell 11 and the top cover 12 and improving the stability of pre-assembly. By ensuring that the height L1 of the bent portion protruding from the inner wall surface of the remaining part of the side wall 111 is less than or equal to 0.05mm, the bending amount of the bent portion can be controlled, reducing assembly difficulty and improving pre-assembly efficiency. It can also reduce the space occupied by the bent portion inside the housing 10 and avoid interference between the bent portion and the battery cells or other structures inside the housing 10.

[0063] In some embodiments of this utility model, the first direction is the thickness direction of the housing 10 of the battery cell 100, and the cover 121 is the housing wall with the largest area among all the housing walls of the housing 10. This facilitates the assembly of components within the battery cell 100, improves the assembly efficiency of the battery cell 100, and also reduces the processing and assembly difficulty of the bottom shell 11 and the top cover 12, thereby improving processing and assembly efficiency.

[0064] The following will refer to Figures 1-4 The present invention describes a battery cell 100 according to two specific embodiments.

[0065] Example 1, refer to Figure 1 The battery cell 100 includes a housing 10, terminals 20, a battery cell, and a sealing pin 30. The battery cell is disposed inside the housing 10, the terminals 20 pass through the housing 10, and the sealing pin 30 seals the position of the liquid injection hole in the housing 10.

[0066] like Figures 1-4 As shown, the housing 10 includes a bottom shell 11 and a top cover 12. The bottom shell 11 is a rectangular box with an open top. The bottom shell 11 is integrally formed and is made of titanium or titanium alloy. The bottom shell 11 includes a bottom wall and a side wall 111. The bottom wall is a rectangular horizontal plate. The side wall 111 is connected to the periphery of the bottom wall and extends vertically upward. The side wall 111 extends in a ring shape along the circumference of the bottom wall.

[0067] The top cover 12 is integrally formed and made of stainless steel, and its hardness is greater than that of the bottom shell 11. The top cover 12 includes a cover body 121 and a flange 122. The cover body 121 is a rectangular horizontal plate. The flange 122 is connected to the periphery of the cover body 121 and extends vertically downward. The flange 122 extends in a ring shape along the circumference of the cover body 121. The flange 122 includes a vertical section and an arc section extending in the up-down direction. The upper end of the vertical section is connected to the periphery of the cover body 121 through the arc section. The top cover 12 covers the upper opening of the bottom shell 11, and the flange 122 is arranged on the side wall 111 facing away from the cavity 101. The flange 122 of the top cover 12 is interference-fitted with the side wall 111 of the bottom shell 11.

[0068] like Figure 3 As shown, the shell 10 satisfies: 0.05mm≤W2≤W1≤0.2mm, 0.2mm≤H3≤H2≤H1≤1.5mm, 0.2mm≤R2≤R1≤0.5mm; where W1 is the wall thickness of the side wall 111 of the bottom shell 11, W2 is the wall thickness of the vertical section of the folded edge 122, H1 is the height of the folded edge 122 in the vertical direction, H2 is the overlap length between the folded edge 122 and the side wall 111 in the vertical direction, H3 is the distance between the upper edge of the side wall 111 and the lower surface of the cover 121, R1 is the radius of the outer arc surface of the arc segment, and R2 is the radius of the inner arc surface of the arc segment.

[0069] like Figure 7 and Figure 8 As shown, in this embodiment, the housing 10 of the battery cell 100 can be welded perpendicularly to the side wall 111 using a welding head 200. Specifically, with the bottom wall of the bottom shell 11 as a reference, the laser welding head 200 is set perpendicularly to the side wall 111 of the bottom shell 11 at 90°, and welding is performed within the overlap length range between the folded edge 122 and the side wall 111.

[0070] Example 2, as Figures 4-6 As shown, the structure of this embodiment is roughly the same as that of embodiment one, with the same components using the same reference numerals. The only difference is that in embodiment one, the welding head 200 is welded perpendicularly to the side wall 111, while in this embodiment two, oblique welding is used.

[0071] Specifically, such as Figure 4 As shown, during the interference fit between the top cover 12 and the bottom shell 11, the upper open position of the side wall 111 of the bottom shell 11 is slightly narrowed inward to form a bent portion, and the bent portion satisfies: 0.01mm≤L1≤0.05mm, 0.05mm≤H4≤0.1mm; where L1 is the height of the bent portion protruding from the inner wall surface of the remaining part of the side wall 111 along the wall thickness direction of the vertical section of the folded edge 122, and H4 is the height of the bent portion above the vertical section along the up-down direction.

[0072] like Figure 5 and Figure 6 As shown, in this embodiment, the housing 10 of the battery cell 100 is connected by oblique welding. During oblique welding, the upper surface of the housing 10 of the battery cell 100 is used as a reference, and the laser welding head 200 is arranged at an angle of 110°-150° with the upper surface of the battery cell 100. The welding area is the upper half of the overlap area of ​​the folded edge 122 and the side wall 111 (H2 / 2) + the height area where the bent part is located (H4).

[0073] In the battery cell 100 of the above embodiment, the top cover 12 and the bottom shell 11 are welded using two metal materials with different melting points through a through-welding process. The through-welding is achieved by utilizing the difference in melting points between the two materials. Because of the difference in melting points, the top cover 12 is made of a metal material with a lower melting point, while the bottom shell 11 is made of a metal material with a relatively higher melting point. On the one hand, this makes the welding tighter and achieves a sealing effect. On the other hand, it ensures that the welding from the outside to the inside does not produce over-welding, and will not cause the innermost layer to be welded through, thus avoiding the risk of battery leakage.

[0074] In the above embodiment, the battery cell 100 has a square steel shell 10. Compared with pouch batteries, the metal shell has higher strength, is less prone to deformation, has better safety performance, and improves space utilization, thereby increasing volumetric energy density. The bottom shell 11 and the top cover 12 are connected by through-welding. Through-welding, compared with seam welding, can reduce welding difficulty, make the welding process easier to control, and reduce the requirements for dimensional tolerances. At the same time, the through-welding area in this embodiment has a relatively sufficient reserved welding area, which facilitates better spot welding, improves welding efficiency and welding yield, and meets the requirements of the sealed shell 10.

[0075] The battery device according to a second aspect of the present invention includes a battery cell 100 according to the first aspect of the present invention described above.

[0076] According to the battery device of the present invention, by setting the battery cell 100 of the first aspect embodiment, the side wall 111 of the bottom shell 11 and the folded edge 122 of the top cover 12 are connected at the overlapping position by a first weld mark, and the first weld mark is formed from the outside to the inside in a direction perpendicular to the first direction, and the melting point of the outer material at the welding position is lower than that of the inner material. Therefore, not only can the connection at the welding position be made tighter and the sealing effect of the welding position be improved, but over-welding can also be avoided, thus avoiding the risk of leakage of the shell 10 at the welding position. This improves the welding efficiency and welding yield between the bottom shell 11 and the top cover 12, meets the sealing performance requirements of the shell 10, improves the safety performance of the battery cell 100, and thus improves the overall performance of the battery device.

[0077] The electrical device according to a third aspect embodiment of the present invention includes a single battery cell according to the first aspect embodiment of the present invention or includes a battery device according to the second aspect embodiment of the present invention. The electrical device may be a mobile phone, portable device, or laptop computer, etc.

[0078] According to the embodiments of the present invention, the overall performance of the electrical device is improved by providing the battery cell 100 of the second aspect embodiment described above.

[0079] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0080] Furthermore, the terms "first" and "second" 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0081] In this utility model, unless otherwise explicitly 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 communication connection; 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. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0082] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell (100), characterized in that, Includes a housing (10), the housing (10) comprising: Bottom shell (11), the bottom shell (11) defining a cavity (101) open on one side in a first direction; A top cover (12) covers the open side of the cavity (101) and includes a cover body (121) and a flange (122). The flange (122) is connected to the periphery of the cover body (121) and extends in a ring shape along the circumference of the cover body (121). The flange (122) overlaps with the side wall (111) of the bottom shell (11) in the first direction and is connected at the overlap position by a first weld mark. In the stacking direction of the sidewall (111) and the folded edge (122), the first solder mark is welded from the outside of the housing (10) toward the cavity (101), and the melting point of the sidewall (111) and the folded edge (122) that are far from the cavity (101) is less than the melting point of the other that is close to the cavity (101).

2. The battery cell (100) according to claim 1, characterized in that, The difference between the melting point of the sidewall (111) and the melting point of the folded edge (122) is 200℃-300℃.

3. The battery cell (100) according to claim 1, characterized in that, One of the bottom shell (11) and the top cover (12) is made of stainless steel, and the other is made of titanium or titanium alloy.

4. The battery cell (100) according to claim 1, characterized in that, In the first direction, the height of the folded edge (122) is 0.25mm-0.7mm, and / or the overlap length between the folded edge (122) and the side wall (111) is 0.15mm-0.5mm.

5. The battery cell (100) according to any one of claims 1-4, characterized in that, One end of the folded edge (122) is connected to the cover (121), and the other end extends toward the bottom shell (11) along the first direction and extends to the side surface of the side wall (111) opposite to the cavity (101).

6. The battery cell (100) according to claim 5, characterized in that, The wall thickness of the folded edge (122) is less than or equal to the wall thickness of the side wall (111), and the wall thickness of both the side wall (111) and the folded edge (122) is 0.05mm-0.25mm.

7. The battery cell (100) according to claim 6, characterized in that, The wall thickness of the sidewall (111) is 0.1mm-0.25mm; and / or the wall thickness of the folded edge (122) is 0.1mm-0.2mm.

8. The battery cell (100) according to claim 5, characterized in that, In the stacking direction of the folded edge (122) and the side wall (111), the top cover (12) and the bottom shell (11) are interference fit.

9. The battery cell (100) according to claim 8, characterized in that, The folded edge (122) is connected to the cover (121) by an arc bend, and the hardness of the top cover (12) is greater than that of the bottom shell (11). In the first direction, one end of the sidewall (111) facing the cover (121) is bent toward the cavity (101) to fit the arcuate inner wall where the folded edge (122) is connected to the cover (121).

10. The battery cell (100) according to claim 9, characterized in that, In the first direction, the height of the bent portion at one end of the sidewall (111) is 0.05mm-0.1mm, and / or, in the stacking direction of the sidewall (111) and the folded edge (122), the height of the bent portion at one end of the sidewall (111) protruding from the inner wall surface of the rest of the sidewall (111) is 0.01mm-0.05mm.

11. The battery cell (100) according to any one of claims 1-4, characterized in that, The first direction is the thickness direction of the housing (10) of the battery cell (100), and the cover (121) is the housing wall with the largest area among all the housing walls of the housing (10).

12. A battery device, characterized in that, Includes the battery cell (100) according to any one of claims 1-11.

13. An electrical appliance, characterized in that, Includes a battery cell (100) according to any one of claims 1-11 or a battery device according to claim 12.

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