Battery cell

Abstract

The utility model provides a battery cell which comprises a shell and a cover plate, at least one end of the side wall of the shell is provided with a shell opening, the cover plate covers the shell opening, and the cover plate and the shell define a containing space; the cover plate is provided with a first plate face away from the containing space, and the side wall is provided with a peripheral side face away from the containing space. The cover plate is welded with the end part of the side wall to form a welding part; the welding part is positioned on one side, close to the accommodating space, of the first plate surface; and / or the welding part is positioned on one side, close to the accommodating space, of the peripheral side surface. According to the battery cell provided by the invention, the cover plate and the end part of the side wall are welded to form the welding part, and the welding part is limited on one side, close to the accommodating space, of the first plate surface and one side, close to the accommodating space, of the peripheral side surface, so that the risk of insulation failure can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, and in particular to a battery cell. BACKGROUND

[0002] At present, due to the advantages of high energy density, high power density, multiple cycle times and long storage time, lithium ion batteries are widely used in portable electronic devices such as mobile phones, digital cameras and laptop computers, and have a wide application prospect in electric vehicles, electric bicycles and other electric vehicles and energy storage facilities. Large and medium-sized electric devices become the key to solving global problems such as energy crisis and environmental pollution. With the increasing perfection of electric vehicle technology, electric vehicles and hybrid vehicles are becoming closer to people's daily life, and there is a huge business opportunity. At the same time, electric vehicles have higher requirements for the appearance and performance of lithium ion batteries that provide energy for them. The importance of lithium ion battery sealing process, especially square lithium ion battery sealing process, is further highlighted.

[0003] In related technologies, the battery sealing process, that is, the process of covering the cover plate on the opening of the shell and welding the cover plate and the shell. The applicant found that the fusion part (or called welding mark) formed by welding the cover plate and the shell can have adverse effects on the structure layer connected to the surface of the cover plate or the surface of the shell. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the purpose of the present application is to provide a battery cell to at least partially solve the problem of adverse effects of the fusion part formed by welding the cover plate and the shell on the structure layer connected to the surface of the cover plate or the surface of the shell.

[0005] In order to achieve the above purpose, the present application provides a battery cell, comprising: a shell and a cover plate, at least one end of the side wall of the shell is provided with a shell opening, the cover plate covers the shell opening, and the cover plate and the shell form a containing space; the cover plate has a first plate surface away from the containing space, and the side wall has an outer peripheral side surface away from the containing space; the cover plate and the end of the side wall are welded to form a fusion part, and the fusion part is located on the side of the first plate surface close to the containing space; and / or, the fusion part is located on the side of the outer peripheral side surface close to the containing space.

[0006] Optionally, the fusion part is arranged along the edge circumference of the cover plate, and the radial section of the fusion part comprises a first edge, the first edge is a circular arc line, and extends from the first plate surface to the outer peripheral side surface.

[0007] Optionally, the arc length of the first edge is 0.6mm to 1.5mm.

[0008] Optionally, the radial section of the fusion portion comprises a second edge, the second edge is a circular arc, and the first edge and the second edge are connected to form a continuous edge.

[0009] Optionally, the arc length of the second edge is 1mm to 2mm.

[0010] Optionally, the fusion depth of the fusion portion along the direction perpendicular to the first plate surface is 0.7mm to 1.1mm.

[0011] Optionally, the fusion width of the fusion portion along the direction perpendicular to the outer circumferential side surface is 0.8mm to 1.4mm.

[0012] Optionally, at least part of the cover plate extends to the outer circumferential side surface along the direction perpendicular to the outer circumferential side surface to cover the end of the side wall; the first plate surface is provided with a thinning groove along the edge circumference, and the thinning groove covers the end of the side wall in the orthographic projection of the shell along the direction perpendicular to the first plate surface; the area of the cover plate provided with the thinning groove is used to form the fusion portion.

[0013] Optionally, the minimum thickness of the area of the cover plate provided with the thinning groove is 0.4mm to 0.8mm.

[0014] Optionally, the cover plate is located on the side of the shell away from the outer circumferential side surface, and the end of the side wall comprises a slope structure; the slope structure is used to form the fusion portion.

[0015] As can be seen from the above, the electric cell provided by the application, the cover plate and the end of the side wall are welded to form a fusion portion, by limiting the fusion portion on the side of the first plate surface close to the accommodation space, the risk of insulation failure due to the local separation of the patch and the first plate surface can be reduced, and the patch can have a better bonding effect with the first plate surface. By limiting the fusion portion on the side of the outer circumferential side surface close to the accommodation space, the risk of insulation failure due to the local separation of the insulating film and the outer circumferential side surface can be reduced, and the insulating film can have a better covering effect with the outer circumferential side surface. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the application or related art, the following will briefly introduce the drawings needed to be used in the embodiments or related art descriptions. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1A top view of the first structure of the battery cell of the present application before welding of the shell and the cover plate;

[0018] Figure 2 A top view of the first structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 1 A partial view of section A-A;

[0019] Figure 3 A top view of the first structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 2 A view of section B after welding;

[0020] Figure 4 A top view of the second structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 2 A view of section B after welding;

[0021] Figure 5 A top view of the second structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 2 A view of section B after welding.

[0022] Figure 6 A top view of the third structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 2 A view of section B after welding;

[0023] Figure 7 A top view of the fourth structure of the battery cell of the present application before welding of the shell and the cover plate; Figure 2 A view of section B after welding;

[0024] Figure 8 A top view of the fifth structure of the battery cell of the present application before welding of the shell and the cover plate. Figure 2 A view of section B after welding.

[0025] Explanation of reference numerals:

[0026] 100, shell; 110, side wall; 111, outer peripheral side; 112, end portion; 120, shell opening;

[0027] 200, cover plate; 210, first plate surface; 220, thinning groove;

[0028] 300, accommodation space; 400, laser;

[0029] 500, first fusion portion; 510, protrusion; 520, flange;

[0030] 600, fusion portion; 610, first edge; 620, second edge;

[0031] 700, slope structure. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0033] It should be noted that the relative arrangement of the components, numerical expressions, and numerical values set forth in these examples do not limit the scope of the present application unless specifically stated otherwise.

[0034] It should be understood that the dimensions of the various parts shown in the drawings are not necessarily to scale for the sake of convenience of description.

[0035] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the scope of the application or its application or uses.

[0036] It should be noted that the technical terms or scientific terms used in the embodiments of the present application should be understood as the usual meaning understood by those skilled in the art unless otherwise defined. The terms "first", "second", and the like used in the embodiments of the present application do not represent any order, number, or importance, but are only used to distinguish different components. The terms "include" or "contain" and the like mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connected" or "connected" and the like are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right", and the like are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0037] The cover plate 200 of the battery cell and the shell 100 can be welded by a side welding process or a top welding process. Figure 1 A top view schematic diagram of the battery cell of the first structure before the shell 100 and the cover plate 200 are welded is shown, Figure 2 For Figure 1 A partial schematic diagram of the A-A section is shown, Figure 1 And Figure 2 The battery cell includes a shell 100 and a cover plate 200, at least one end of the side wall 110 of the shell 100 is provided with a shell opening 120, and the cover plate 200 covers the shell opening 120. The cover plate 200 and the shell 100 form a containing space 300.

[0038] The structure and direction shown in Figure 1 For example, the cover plate 200 is arranged in the shell opening 120, and before welding, the cover plate 200 and the shell 100 have a continuous annular gap therebetween, and the gap is located at the top of the battery cell. When the cover plate 200 and the shell 100 are laser welded, the laser 400 is directed from above the battery cell to the gap between the cover plate 200 and the shell 100.

[0039] Figure 3 Showing Figure 2 A schematic diagram of part B after welding, as shown below. Figure 3 A portion of the cover plate 200 and a portion of the housing 100 near the gap are fused together by the laser 400. After cooling and solidification, they form a first welded part 500, through which the cover plate 200 and the housing 100 can be connected.

[0040] Combination Figure 3 If the first welding part 500 has a protrusion 510 that protrudes from the top surface of the cover plate 200, when a patch is subsequently attached to the top surface of the cover plate 200, interference will occur between the protrusion 510 and the patch, which may lead to insulation failure and other defects.

[0041] Combination Figure 3 If the first welded portion 500 has a flange 520 protruding from the outer surface of the sidewall 110, interference will occur between the flange 520 and the insulating film when an insulating film (or blue film) is subsequently applied to the outer surface of the sidewall 110. This will prevent the area of ​​the insulating film near the flange 520 from adhering to the outer surface of the sidewall 110, resulting in air bubbles. Furthermore, when multiple cells are stacked to form a battery module, if the flange 520 of one cell protrudes too high, it will cause frictional interference with adjacent cells along the stacking direction, potentially damaging the insulating film of the adjacent cells and leading to insulation failure or other defects.

[0042] Figure 4 The second type of battery cell was demonstrated. Figure 2 A schematic diagram of part B after welding. Figure 5 The second type of battery cell was demonstrated. Figure 2 A schematic diagram of part B before welding.

[0043] To solve the above problems, such as Figure 4 and Figure 5 In some embodiments, the cover plate 200 has a first plate surface 210 away from the receiving space 300; the cover plate 200 is welded to the end 112 of the sidewall 110 to form a welded portion 600, the welded portion 600 being located on the side of the first plate surface 210 near the receiving space 300.

[0044] by Figure 4 Taking the direction and structure shown as an example, the welding part 600 is located entirely on the side of the first plate surface 210 near the receiving space 300, that is, the welding part 600 is entirely located below the first plate surface 210. When connecting the patch to the first plate surface 210 of the cover plate 200, since the welding part 600 does not protrude from the first plate surface 210, it will not interfere with the patch, ensuring that the patch is tightly attached to the first plate surface 210, which helps to improve the insulation performance of the battery cell.

[0045] In some embodiments, the side wall 110 has an outer peripheral side 111 away from the accommodation space 300, and the welding portion 600 is located on the side of the outer peripheral side 111 close to the accommodation space 300.

[0046] For example, when the battery cell is a square shell battery cell, the side wall 110 of the shell 100 is in a square cylindrical structure, the accommodation space 300 is located in the interior of the square cylindrical structure, and the outer peripheral side 111 of the side wall 110 is the circumferential outer side of the square cylindrical structure.

[0047] For example, when the battery cell is a square shell battery cell, the side wall 110 of the shell 100 is in a square cylindrical structure, the accommodation space 300 is located in the interior of the square cylindrical structure, and the outer peripheral side 111 of the side wall 110 is the circumferential outer side of the square cylindrical structure. Figure 4 For example, when the battery cell is a square shell battery cell, the side wall 110 of the shell 100 is in a square cylindrical structure, the accommodation space 300 is located in the interior of the square cylindrical structure, and the outer peripheral side 111 of the side wall 110 is the circumferential outer side of the square cylindrical structure.

[0048] The battery cell provided in the embodiment has the welding portion 600 formed by welding the end portion 112 of the side wall 110 to the cover plate 200. By limiting the welding portion 600 to the side of the first plate face 210 close to the accommodation space 300, the welding portion 600 can be prevented from protruding from the first plate face 210, so that the patch can be tightly attached to the first plate face 210, and the risk of insulation failure due to partial separation of the patch from the first plate face 210 can be reduced. By limiting the welding portion 600 to the side of the outer peripheral side 111 close to the accommodation space 300, the welding portion 600 can be prevented from protruding from the outer peripheral side 111, so that the insulation film can be tightly wrapped around the outer peripheral side 111, and the risk of insulation failure due to partial separation of the insulation film from the outer peripheral side 111 can be reduced.

[0049] For example, when the battery cell is a square shell battery cell, the side wall 110 of the shell 100 is in a square cylindrical structure, the accommodation space 300 is located in the interior of the square cylindrical structure, and the outer peripheral side 111 of the side wall 110 is the circumferential outer side of the square cylindrical structure. Figure 4 In some embodiments, the welding portion 600 is arranged along the edge circumference of the cover plate 200, and the radial cross section of the welding portion 600 includes a first edge 610, the first edge 610 is a circular arc, and extends from the first plate face 210 to the outer peripheral side 111.

[0050] In the embodiment, the welding portion 600 is arranged in a ring shape along the annular gap between the side wall 110 and the cover plate 200, and the welding portion 600 is in a ring structure connected end to end. By limiting the shape of the radial cross section of the welding portion 600, the overall shape of the welding portion 600 can be standardized.

[0051] The first edge 610 in the embodiment is the edge of the exposed part of the radial section of the fusion portion 600, and the first edge 610 is defined as a circular arc line, which can make the shape of the exposed part of the fusion portion 600 more regular, help prevent the fusion portion 600 from forming the protrusion 510 or the flange 520, and further reduce the risk of insulation failure.

[0052] In some embodiments, the arc length b of the first edge 610 is 0.6 mm to 1.5 mm.

[0053] For example, the arc length b can be 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm.

[0054] If the arc length b of the first edge 610 is too large, the fusion range representing the end portion 112 of the cover plate 200 and the side wall 110 is too large, which may cause the side wall 110 and the cover plate 200 to be deformed. If the arc length b of the first edge 610 is too small, the fusion part representing the end portion 112 of the cover plate 200 and the side wall 110 is too small, which may cause the connection between the side wall 110 and the cover plate 200 to be unreliable, and there is a safety hazard.

[0055] To avoid the above problems, the arc length b of the first edge 610 is limited to 0.6 mm to 1.5 mm in the embodiment, which can ensure the connection reliability of the side wall 110 and the cover plate 200, and avoid the deformation of the side wall 110 and the cover plate 200.

[0056] For example, Figure 3 The distance that the fusion portion 600 extends downward from the top end of the protrusion 510 is the fusion depth.

[0057] As shown in FIG. 6, if the bottom shape of the first fusion portion 500 is irregular, the fusion depth of some areas of the first fusion portion 500 may be significantly different from the fusion depth of the surrounding areas. Figure 3 For example, Figure 3 In the example shown in FIG. 6, the fusion depth of the center of the first fusion portion 500 is much greater than the surrounding areas, which causes the fusion depth of the first fusion portion 500 to be inconsistent, and there is a risk of the molten pool (the cover plate 200 and the side wall 110 that are fused together in a pool shape) being too deep and missing the fusion bead during welding. In addition, the irregular shape of the first fusion portion 500 also causes the metal crystallization boundary to be unstable, which has a risk of low metal strength and fatigue performance.

[0058] To avoid the above problems, as shown in FIG. 7, Figure 4 In some embodiments, the radial section of the fusion portion 600 includes a second edge 620, the second edge 620 is a circular arc line, and the first edge 610 and the second edge 620 are connected to each other to form a continuous edge.

[0059] In the embodiment, the radial cross-sectional shape of the welding portion 600 is a shape enclosed by the first edge 610 and the second edge 620, that is, the edge of the part where the welding portion 600 is connected to the side wall 110 and the cover plate 200. Defining the second edge 620 as a circular arc line can at least make the shape of the bottom of the welding portion 600 more regular, which helps to improve the consistency of the penetration of the welding portion 600, and helps to improve the metal strength, fatigue performance, and bursting strength of the welding portion 600.

[0060] In some embodiments, the arc length c of the second edge 620 is 1 mm to 2 mm.

[0061] For example, the arc length c can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm.

[0062] If the arc length c of the second edge 620 is too large, the penetration of the welding portion 600 will be too deep, and there may be a risk of missing a molten bead during welding, which may adversely affect the bare battery cell arranged in the accommodation space 300. If the arc length c of the second edge 620 is too small, the penetration of the welding portion 600 will be too shallow, which means that the molten part of the end portion 112 of the cover plate 200 and the side wall 110 will be too small, which may result in insufficient connection reliability of the side wall 110 and the cover plate 200, and may pose a safety hazard.

[0063] To avoid the above problems, the arc length c of the second edge 620 is limited to 1 mm to 2 mm in the embodiment, which can not only ensure the connection reliability of the side wall 110 and the cover plate 200, but also reduce the risk of missing a molten bead during welding.

[0064] As Figure 4 In some embodiments, the penetration d of the welding portion 600 in the direction perpendicular to the first plate surface 210 (such as the Z direction in Figure 4 In some embodiments, the penetration d of the welding portion 600 in the direction perpendicular to the first plate surface 210 (such as the Z direction in

[0065] For example, the penetration d can be 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, or 1.1 mm.

[0066] As can be seen from the foregoing, if the penetration of the welding portion 600 is too deep, not only the cover plate 200 and the side wall 110 may be bent and deformed, but also there may be a risk of missing a molten bead during welding. If the penetration of the welding portion 600 is too shallow, the connection reliability of the side wall 110 and the cover plate 200 will be insufficient, and the cover plate 200 may be separated from the side wall 110. When the battery cell overheats or the air pressure increases, the welding portion 600 may be broken before the explosion-proof valve of the battery cell is opened, which may result in damage to the battery cell packaging structure and pose a safety hazard.

[0067] To avoid the above problems, the present embodiment limits the penetration depth d of the fusion portion 600 to 0.7mm to 1.1mm, which can ensure the connection reliability of the side wall 110 and the cover plate 200, and reduce the risk of missing the fusion bead during welding.

[0068] As shown in Figure 4 , in some embodiments, the fusion width e of the fusion portion 600 along the direction perpendicular to the outer circumferential side surface 111 (such as the Y direction in Figure 4 ) is 0.8mm to 1.4mm.

[0069] For example, the fusion width e can be 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm or 1.4mm.

[0070] If the fusion width e of the fusion portion 600 is too narrow, the fusion portion 600 and the molten portion of the cover plate 200 will be too small, resulting in insufficient connection reliability of the side wall 110 and the cover plate 200. If the fusion width e of the fusion portion 600 is too wide, it may cause the cover plate 200 to be deformed.

[0071] To avoid the above problems, the present embodiment limits the fusion width e of the fusion portion 600 to 0.8mm to 1.4mm, which can ensure the connection reliability of the side wall 110 and the cover plate 200, and reduce the risk of the cover plate 200 being deformed.

[0072] As shown in Figure 4 and Figure 5 , in some embodiments, at least part of the cover plate 200 extends to the outer circumferential side surface 111 along the direction perpendicular to the outer circumferential side surface 111 to cover the end portion 112 of the side wall 110; the first plate surface 210 is provided with a thinning groove 220 along the edge peripheral ring, and along the direction perpendicular to the first plate surface 210, the thinning groove 220 covers the end portion 112 of the side wall 110 in the orthographic projection of the shell 100; the area of the cover plate 200 provided with the thinning groove 220 is used to form the fusion portion 600.

[0073] For example, Figure 6 , the third structure of the battery cell is shown in Figure 2 , the schematic diagram of the B part of the battery cell before welding is shown in Figure 6 , the groove bottom of the thinning groove 220 can be an inclined surface, and the depth of the thinning groove 220 gradually increases from the center of the cover plate 200 to the edge direction of the cover plate 200.

[0074] For example, Figure 5 , the groove bottom of the thinning groove 220 can be a flat surface.

[0075] For example, Figure 5 and Figure 6 , the thinning groove 220 penetrates to the circumferential side wall of the cover plate 200.

[0076] For example, the cover plate 200 includes a portion extending into the housing opening 120, or the entire cover plate 200 is located on the side of the end portion 112 of the sidewall 110 away from the accommodation space 300.

[0077] For example, in a direction perpendicular to the outer circumferential side surface 111, the width g of the thinning groove 220 is greater than the thickness h of the sidewall 110.

[0078] If a portion of the cover plate 200 (hereinafter referred to as a cover plate edge portion) covers the end portion 112 of the sidewall 110, when welding the cover plate 200 and the end portion 112 of the sidewall 110, the cover plate edge portion and the end portion 112 of the sidewall 110 need to be melted together to enable the formed fusion portion 600 to reliably connect the cover plate 200 and the sidewall 110. However, if the thickness of the cover plate edge portion is large, the energy consumed to melt the cover plate edge portion during welding is too large, which can cause the melted portion of the end portion 112 of the sidewall 110 to be small, making it difficult to reliably connect the cover plate 200 and the sidewall 110.

[0079] Therefore, the present embodiment reduces the thickness of the cover plate edge portion by providing the thinning groove 220, thereby reducing the energy consumed to melt the cover plate edge portion during welding, ensuring that the end portion 112 of the sidewall 110 has a large melted portion, thereby enabling the formation of the fusion portion 600, ensuring that a relatively reliable connection between the cover plate 200 and the sidewall 110 can be formed, and improving the welding effect between the two.

[0080] For example, the thickness f can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. Figure 5 In some embodiments, the minimum thickness f of the region of the cover plate 200 provided with the thinning groove 220 is 0.4 mm to 0.8 mm.

[0081] For example, the thickness f can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm.

[0082] If the thickness f is too large, the melted portion of the end portion 112 of the sidewall 110 can still be too small, making it difficult to reliably connect the cover plate 200 and the sidewall 110. If the thickness f is too small, the melted portion of the end portion 112 of the sidewall 110 can be too large, causing the fusion portion 600 to be too close to the accommodation space 300, which can adversely affect the sealing performance of the battery cell.

[0083] Therefore, the present embodiment limits the thickness f to 0.4 mm to 0.8 mm, which can ensure that the cover plate 200 and the sidewall 110 can be reliably connected, and can also ensure the sealing performance of the battery cell.

[0084] For example, the thickness f can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm. Figure 5When laser welding is performed on the edge portion of the cover plate, the laser 400 can be aligned with the center of the gap between the cover plate 200 (the portion extending into the opening 120 of the shell) and the side wall 110, or the laser 400 can be more offset towards the shell 100 (the offset distance can be 0-0.2 mm).

[0085] For example, when laser welding is performed, a multi-mode annular laser with a fiber core diameter of 100 μ / 300 μ or 100 μ / 600 μ and a laser power of ≥4000 W (with a central power of 800-1600 W and an outer ring power of 1000-2000 W) can be used, and the welding speed can be 100-200 mm / s and the welding defocus can be 0±2 defocus amounts.

[0086] Figure 7 FIG. 6 shows a schematic view of a battery cell with a fourth structure before welding of the B portion, and FIG. 7 shows a schematic view of the battery cell after welding of the B portion. Figure 2 Figure 4 Figure 7 In some embodiments, the cover plate 200 is located on the side of the shell 100 away from the outer peripheral side 111, and the end portion 112 of the side wall 110 includes a slope structure 700 for forming the fusion portion 600.

[0087] For example, as shown in FIG. 8, the slope structure 700 can face the cover plate 200. Figure 7

[0088] For example, as shown in FIG. 9, the slope structure 700 can face away from the cover plate 200. Figure 8 FIG. 10 shows a schematic view of a battery cell with a fifth structure before welding of the B portion, and FIG. 11 shows a schematic view of the battery cell after welding of the B portion. Figure 2 Figure 8

[0089] In this embodiment, by providing the slope structure 700 on the end portion 112 of the side wall 110, the energy consumed for melting the end portion 112 of the side wall 110 can be reduced when welding the cover plate 200 and the side wall 110, and the end portion 112 of the side wall 110 can have a larger melting portion, and the cover plate 200 can also have a larger melting portion, so that the fusion portion 600 can be formed, and a more reliable connection between the cover plate 200 and the side wall 110 can be ensured, and the welding effect between the two can be improved.

[0090] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims.

[0091] Each of the embodiments in the present application is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be understood by mutual reference.

[0092] ​​​​​The description of the application is presented for purposes of illustration and description, and not by limitation. Numerous modifications and variations on the embodiments described herein will be apparent to those of ordinary skill in the art in light of the foregoing description. The embodiments described herein are chosen and described in order to best explain the principles of the application and its practical application to thereby enable others skilled in the art to best utilize the application. Various embodiments of the application are contemplated and can be made without departing from the spirit or scope of the application.

[0093] It should be understood that any of the above-described embodiments can be implemented in the form of control logic using hardware (e.g. an application specific integrated circuit or field programmable gate array) or software (e.g. computer software on a tangible processor readable medium). The disclosure is to be considered as not limited to the embodiments described herein and as encompassing all embodiments that can be derived from the above description in light of the appended claims.

[0094] Although the application has been described in conjunction with specific embodiments thereof, numerous alternatives, modifications, and variations will be readily apparent to those of ordinary skill in the art in light of the foregoing description. The scope of the application is not to be limited by the foregoing description.

[0095] Embodiments of the application are intended to cover any and all alternatives, modifications, and variations of the above-described embodiments. Accordingly, any and all such alternatives, modifications, and variations should be included within the scope of the application.

Claims

1. An electric cell, characterized by, The application relates to a shell and a cover plate, at least one end of a side wall of the shell is provided with a shell opening, the cover plate covers the shell opening, the cover plate and the shell form a containing space, the cover plate has a first plate surface away from the containing space, the side wall has a peripheral side surface away from the containing space, the cover plate is welded with the end of the side wall and forms a fusion joint, the fusion joint is located on one side of the first plate surface close to the containing space, and / or the fusion joint is located on one side of the peripheral side surface close to the containing space. The fusion joint is arranged along the edge circumference of the cover plate, the radial section of the fusion joint comprises a first edge, the first edge is a circular arc line, and extends from the first plate surface to the peripheral side surface. The arc length of the first edge is 0.6-1.5 mm. The radial section of the fusion joint comprises a second edge, the second edge is a circular arc line, and is connected with the first edge to form a continuous edge.

2. The electric cell of claim 1, wherein, The arc length of the second edge is 1-2 mm.

3. The electric cell of claim 2, wherein, The fusion depth of the fusion joint along the direction perpendicular to the first plate surface is 0.7-1.1 mm.

4. The electric cell of claim 2, wherein, The fusion width of the fusion joint along the direction perpendicular to the peripheral side surface is 0.8-1.4 mm.

5. The electric cell of claim 4, wherein, At least part of the cover plate extends to the peripheral side surface along the direction perpendicular to the peripheral side surface to cover the end of the side wall, the first plate surface is provided with a thinning groove along the edge circumference, and the thinning groove covers the end of the side wall in the orthographic projection of the shell along the direction perpendicular to the first plate surface.

6. The electric cell of claim 1, wherein, The area of the cover plate provided with the thinning groove is used to form the fusion joint.

7. The electric cell of claim 1, wherein, The minimum thickness of the area of the cover plate provided with the thinning groove is 0.4-0.8 mm.

8. The electric cell of claim 1, wherein, The cover plate is located on one side of the shell away from the peripheral side surface, and the end of the side wall comprises a slope structure. The slope structure is used to form the fusion joint.

9. The electric cell of claim 8, wherein, ​ 10. The electric cell of claim 1, wherein, ​ ​

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