Manufacturing method for battery cell, battery cell, casing, top cover, and electrical device

Abstract

A manufacturing method for a battery cell (100), a battery cell (100), a casing (10), a top cover (20), and an electrical device. The manufacturing method for a battery cell (100) comprises: providing a casing (10), such that the casing (10) has an open end, and the casing (10) has a first beveled edge area (11) at the open end; providing a top cover (20), such that the top cover (20) has a second beveled edge area (21), the second beveled edge area (21) matching the inclination angle of the first beveled edge area (11); fitting the top cover (20) to the open end of the casing (10), the second beveled edge area (21) and the first beveled edge area (11) being connected to form a butt joint seam, and the extension direction of the butt joint seam facing the top cover (20); welding the top cover (20) and the casing (10) along the butt joint seam, so that a welding melt pool bottom portion (100a) is located on the top cover (20). According to the manufacturing method for a battery cell (100), the battery cell (100), the shell (10), the top cover (20), and the electrical device, the melt pool bottom portion (100a) produced by welding the shell (10) and the top cover (20) is located on the top cover (20), which can reduce adverse effects caused when there is a defect in the melt pool bottom portion (100a), reduce damage to the strength of the casing (10) from a stress concentration point generated by an external force acting on the casing (10), and improve the strength of the welded structure of the battery cell (100).

Description

Manufacturing method of battery cell, battery cell, shell, top cover and electric device

[0001] Cross-reference to related applications

[0002] The present disclosure is based on and claims priority to Chinese Patent Application No. 202410459823.4, filed on April 17, 2024, entitled "Manufacturing method of battery cell, battery cell, shell, top cover and electric device", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, and in particular to a manufacturing method of battery cell, battery cell, shell, top cover and electric device. BACKGROUND

[0004] In related technologies, the battery cell includes a shell and a top cover, as shown in FIG. 17, the shell 10 and the top cover 20 are connected by welding, and the welding is performed from directly above the top cover to the bottom along the welding direction Z3. However, during welding, defects such as pores at the bottom of the molten pool are easily generated in the gap between the shell 10 and the top cover 20. When the shell 10 is subjected to an external force, stress concentration points are formed at the defects, which causes the shell 10 to crack, and the crack gradually expands, resulting in damage to the shell 10.

[0005] SUMMARY

[0006] Therefore, a first aspect of embodiments of the present disclosure provides a manufacturing method of battery cell to reduce the adverse effects caused by defects at the bottom of the molten pool. The manufacturing method includes: providing a shell, the shell having an open end, the shell having a first beveled edge region at the open end; providing a top cover, the top cover having a second beveled edge region, the second beveled edge region being adapted to the inclination angle of the first beveled edge region; fitting the top cover to the open end of the shell, the second beveled edge region and the first beveled edge region forming an abutment joint, the extension direction of the abutment joint being towards the top cover; and welding the top cover and the shell along the abutment joint, so that the bottom of the molten pool after welding is located on the top cover.

[0007] The manufacturing method of battery cell provided by embodiments of the present disclosure can reduce the adverse effects caused by defects at the bottom of the molten pool, reduce the damage to the strength of the shell caused by stress concentration points generated by external forces on the shell, and improve the welding structural strength of the battery cell. In some embodiments, the first beveled edge region is an inner beveled edge region, the top cover has a first straight edge region connected to the second beveled edge region, and the first straight edge region is connected to the inner side wall of the shell.

[0008] Thus, when the top cover and the shell are welded, the position and range of the bottom of the molten pool can be adjusted, the possibility of the bottom of the molten pool being outside the top cover is reduced, and the welding structure strength of the battery cell is improved.

[0009] In some embodiments, the open end of the shell has a second straight edge region connected with the first bevel edge region, and the second straight edge region is flush with the upper surface of the top cover.

[0010] Thus, when the top cover and the shell are welded, the second straight edge region can be positioned, and the welding operation is facilitated.

[0011] In some embodiments, the top cover has a third straight edge region connected with the second bevel edge region, and the third straight edge region is flush with the outer side wall of the shell.

[0012] Thus, the top cover can be arranged on the shell, and the stability of the connection between the shell and the top cover is improved. Meanwhile, when the top cover and the shell are welded, the third straight edge region can be positioned, and the welding operation is facilitated.

[0013] In some embodiments, the first bevel edge region is an outer bevel edge region, the top cover has a third straight edge region connected with the second bevel edge region, and the third straight edge region is flush with the outer side wall of the shell.

[0014] Thus, the top cover can be arranged on the shell, and the stability of the connection between the shell and the top cover is improved. Meanwhile, when the top cover and the shell are welded, the third straight edge region can be positioned, and the welding operation is facilitated.

[0015] In some embodiments, the shell has a second straight edge region connected with the first bevel edge region, and the second straight edge region is connected with the lower surface of the top cover.

[0016] Thus, the top cover can be arranged on the shell, and the stability of the connection between the shell and the top cover is improved.

[0017] In some embodiments, the inclination angle of the first bevel edge region and the inclination angle of the second bevel edge region are both 15°-75° relative to the horizontal direction.

[0018] Thus, the shell and the top cover can be assembled before welding, the possibility of the bottom of the molten pool being outside the top cover is reduced, and the welding structure strength of the battery cell is improved.

[0019] In some embodiments, the inclination angle of the first bevel edge region and the inclination angle of the second bevel edge region are both 40°-60° relative to the horizontal direction.

[0020] Thus, the shell and the top cover can be assembled before welding, and the possibility of the bottom of the molten pool being outside the top cover is further reduced, and the welding structure strength of the battery cell is improved.

[0021] A second aspect of the embodiments of the present disclosure aims to provide an electric core, comprising a shell and a top cover. The shell has an open end; the top cover is fitted to the open end of the shell, and the top cover is welded to the shell, and the bottom of the molten pool after welding is located on the top cover.

[0022] The bottom of the molten pool generated by welding the shell and the top cover is generated on the top cover, and compared with the bottom of the molten pool generated on the shell, the damage caused by defects such as pores generated by the bottom of the molten pool is smaller.

[0023] In some embodiments, the thickness of the top cover near the shell region is greater than the thickness of the shell near the top cover region.

[0024] The bottom of the molten pool is generated in the thicker region of the top cover, which reduces the possibility of damage to the top cover caused by stress concentration.

[0025] In some embodiments, the materials of the shell and the top cover are both aluminum alloy, and the welding of the shell and the top cover is laser welding.

[0026] In this way, the materials of the shell and the top cover are set to be aluminum alloy, which can improve the strength of the electric core. The laser welding method can improve the positioning accuracy, reduce the generated molten depth, and improve the weld quality.

[0027] A third aspect of the embodiments of the present disclosure aims to provide a shell, which is provided in the manufacturing method of any of the above.

[0028] A fourth aspect of the embodiments of the present disclosure aims to provide a top cover, which is provided in the manufacturing method of any of the above.

[0029] A fifth aspect of the embodiments of the present disclosure aims to provide an electric device, comprising an electric core manufactured according to the manufacturing method of any of the above, for providing electric energy; or, comprising an electric core of any of the above, for providing electric energy. BRIEF DESCRIPTION OF DRAWINGS

[0030] FIG. 1 is a flowchart of a manufacturing method of an electric core according to one or more embodiments;

[0031] FIG. 2 is a partial structural schematic diagram of a shell and a top cover of a first electric core according to one or more embodiments, which are welded to form a bottom of a molten pool;

[0032] FIG. 3 is a partial structural schematic diagram of a top cover according to the embodiment shown in FIG. 2;

[0033] FIG. 4 is a partial structural schematic diagram of a shell according to the embodiment shown in FIG. 2;

[0034] FIG. 5 is a partial structural schematic diagram of a shell and a top cover of a second electric core according to one or more embodiments, which are welded to form a bottom of a molten pool;

[0035] FIG. 6 is a partial structural schematic diagram of a top cover according to the embodiment shown in FIG. 5;

[0036] Fig. 7 is a schematic diagram of a partial structure of a shell according to the embodiment shown in Fig. 5;

[0037] Fig. 8 is a schematic diagram of a partial structure of a shell and a top cover welded to form a bottom of a molten pool of a third type of battery cell according to one or more embodiments;

[0038] Fig. 9 is a schematic diagram of a partial structure of a top cover according to the embodiment shown in Fig. 8;

[0039] Fig. 10 is a schematic diagram of a partial structure of a shell according to the embodiment shown in Fig. 8;

[0040] Fig. 11 is a schematic diagram of a partial structure of a shell and a top cover welded to form a bottom of a molten pool of a fourth type of battery cell according to one or more embodiments;

[0041] Fig. 12 is a schematic diagram of a partial structure of a top cover according to the embodiment shown in Fig. 11;

[0042] Fig. 13 is a schematic diagram of a partial structure of a shell according to the embodiment shown in Fig. 11;

[0043] Fig. 14 is a schematic diagram of a partial structure of a shell and a top cover welded to form a bottom of a molten pool of a fifth type of battery cell according to one or more embodiments;

[0044] Fig. 15 is a schematic diagram of a partial structure of a top cover according to the embodiment shown in Fig. 14;

[0045] Fig. 16 is a schematic diagram of a partial structure of a shell according to the embodiment shown in Fig. 14;

[0046] Fig. 17 is a schematic diagram of a partial structure of a shell and a top cover welded to form a bottom of a molten pool of a battery cell in the related art.

[0047] Reference Signs Battery cell 100; bottom of molten pool 100a; shell 10; first bevel region 11; second straight edge region 12; inner side wall 14; outer side wall 15; top cover 20; second bevel region 21; first straight edge region 22; third straight edge region 23; upper surface 24; lower surface 25; abutment line L1; outer end point D1; inner end point D2. DETAILED DESCRIPTION

[0048] The embodiments of the technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present disclosure, and therefore only serve as examples, and cannot limit the protection scope of the present disclosure.

[0049] In the description of the embodiments of the disclosure, it needs to be explained that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the disclosure and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the disclosure.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion.

[0051] In the description of the embodiments of the disclosure, the technical terms "first", "second", "third" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0052] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The occurrence of the phrase in various places in the specification is not necessarily referring to the same embodiment, nor is it necessarily a separate or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that embodiments described herein can be combined with other embodiments.

[0053] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical terms "connection" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the disclosure can be understood according to the specific circumstances.

[0054] The battery includes a plurality of battery cells. In the battery, the plurality of battery cells can be connected in series, in parallel, or in a mixed connection, where the mixed connection means that some of the plurality of battery cells are connected in series and some are connected in parallel. The plurality of battery cells can be directly connected in series, in parallel, or in a mixed connection, and the whole formed by the plurality of battery cells is placed in the box of the battery; of course, the battery can also be in the form of a plurality of battery cells connected in series, in parallel, or in a mixed connection to form a battery module, and a plurality of battery modules are connected in series, in parallel, or in a mixed connection to form a whole, which is placed in the box of the battery.

[0055] In the embodiments of the present disclosure, the battery cell can be used in a power consumption device using a battery as a power source or a variety of energy storage systems using a battery as an energy storage element, such as an energy storage container. The battery can be a secondary battery, which refers to a battery that can be used continuously by activating active materials through charging after the battery is discharged. The battery can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, or the like. The battery cell can be a prism or other shape. The prism battery cell includes a square can battery cell or a multi-prism battery cell, such as a hexagonal prism battery cell, and the present disclosure does not have a particular limitation.

[0056] The present disclosure takes a square can battery cell as an example for illustration. It should be noted that in FIGS. 2, 5, 8, 11, 14, and 17, Z1 refers to up, Z2 refers to down, and Z3 refers to a welding direction. The irregular curve pointing in the welding direction Z3 is a molten pool generated after welding. In the related art, as shown in FIG. 17, the battery cell includes a shell 10 and a top cover 20, and a molten pool bottom 100a formed by welding the shell 10 and the top cover 20 is located between the shell 10 and the top cover 20. The shell 10 is prone to cracking at welding defects such as pores formed after the shell 10 is subjected to stress, causing damage to the shell. Since the thickness of the shell 10 is generally thinner than the thickness of the top cover 20, if the molten pool bottom 100a is located between the shell 10 and the top cover 20, the welding defects have a greater impact on the shell 10.

[0057] Therefore, referring to FIG. 1, the embodiments of the present disclosure provide a manufacturing method of a battery cell, which includes the following steps.

[0058] S1: providing a shell, so that the shell has an open end and the shell has a first bevel region at the open end;

[0059] S2: providing a top cover, so that the top cover has a second bevel region, and the second bevel region is adapted to the inclination angle of the first bevel region;

[0060] S3: fitting the top cover to the open end of the shell, so that the second bevel region and the first bevel region form an abutment joint, and the extension direction of the abutment joint is toward the top cover;

[0061] S4: welding the top cover and the shell along the abutment joint, so that the molten pool bottom after welding is located on the top cover.

[0062] It should be noted that the order of the above steps S1 and S2 is not limited and can be performed simultaneously. The provided shell and top cover can be processed by outsourcing to external enterprises or purchased, or processed internally.

[0063] Referring to FIGS. 2-16, the molten pool refers to the portion of the base material melted into a pool by the heat of the welding arc, and in the present disclosure, refers to the portion of the liquid metal having a certain geometric shape formed on the top cover 20 and the shell 10 during welding, which corresponds to the irregular curve in FIGS. 2, 5, 8, 11, and 14 after solidification. The bottom of the molten pool 100a is located at the deepest part of the molten pool in the welding direction. The bottom of the molten pool 100a of the welded battery can be obtained by crystal phase analysis. The crystal phase analysis can be XRD (X-ray diffraction) analysis. When X-rays pass through the polycrystalline phase or single crystal phase of the bottom of the molten pool 100a, a specific X-ray diffraction pattern is formed. By analyzing these patterns and combining the corresponding data, the crystal phase of the material at the bottom of the molten pool 100a can be determined. Exemplarily, the first bevel area 11 is formed with a first bevel, and the second bevel area 21 is formed with a second bevel. The top cover 20 is fitted to the open end of the shell 10, and the first bevel and the second bevel abut to form an abutment seam for welding, and the extension direction of the abutment seam is towards the top cover 20. Exemplarily, the gap of the laser-welded abutment seam is generally less than or equal to 0.3 mm, for example, 0.1 mm, 0.2 mm, or 0.3 mm.

[0064] The partial structure of the battery cell 100 is cut to form a sectional view to show the cross section of the shell 10 and the top cover 20 and the molten pool formed during welding. Exemplarily, referring to FIGS. 2, 5, 8, 11, and 14, in the cross section of the shell 10 and the top cover 20, the first bevel area 11 and the second bevel area 21 form an abutment seam between the top cover 20 and the shell 10. The abutment seam is schematically shown as an abutment line L1 in the sectional view. One end of the abutment line L1 is an inner end point D2 located inside the structure of the top cover 20 and the shell 10, and the other end of the abutment line L1 is an outer end point D1 located on the outer periphery of the top cover 20 and the shell 10. Taking a square battery cell as an example, in the sectional view formed after cutting, the outer periphery of the shell 10 and the top cover 20 forms a rectangle, the inner end point D2 is located inside the rectangle, and the outer end point D1 is located on the side line of the rectangle.

[0065] The direction of the butt joint can be upward relative to the horizontal plane from the outer periphery of the top cover 20 and the shell 10 towards the inside of the top cover 20, or downward relative to the horizontal plane from the outer periphery of the top cover 20 and the shell 10 towards the inside of the top cover 20. In laser welding, the welding direction Z3 can be along the direction of the butt line L1, which helps the laser beam to act stably and uniformly on the welding object, realizes deep penetration welding, and the formation of the weld is more uniform and continuous, and reduces the generation of welding defects, and obtains larger penetration and better weld shape. At the same time, it also helps to reduce the heat-affected zone in the welding process, reduce the welding stress and deformation, thereby improving the strength and corrosion resistance of the weld. The welding direction Z3 can also be arranged at an angle with the butt line L1, thereby adjusting the position of the weld pool bottom 100a. In order to make the weld pool bottom 100a located on the top cover 20, if the welding direction Z3 is arranged at an angle with the butt line L1, the welding direction Z3 is as far as possible towards the direction of the top cover 20 under the premise of considering the penetration.

[0066] It can be understood that when the angle between the welding direction Z3 and the butt line L1 is too large, the weld pool bottom 100a can exceed the top cover 20 and be generated outside the top cover 20 or on the shell 10. Exemplarily, the angle between the welding direction Z3 and the butt line L1 is less than 40°, so as to reduce the possibility of adverse effects caused by the weld pool bottom 100a not being generated in the top cover 20.

[0067] The intersection of the outer periphery of the top cover 20 and the shell 10 generates an outer joint (corresponding to the outer endpoint D1 in the cross section), which can be located on the top surface of the shell 10 and the top cover 20 as a whole, or on the side surface of the shell 10 and the top cover 20 as a whole. When the outer joint is on the top surface or the side surface, the extension direction of the first bevel area 11 and the second bevel area 21 (corresponding to the butt line L1 in the cross section) is from the outer periphery of the top cover 20 and the shell 10 towards the inside of the top cover 20, so that the weld pool bottom 100a is located on the top cover 20. By controlling the weld direction or the welding angle, the position of the weld pool bottom 100a can be adjusted. For example, in laser welding, the laser beam can be controlled to weld along the welding direction Z3, so that the weld pool bottom 100a is formed on the top cover 20.

[0068] The extension direction of the first bevel area 11 and the second bevel area 21 is towards the top cover 20, and the welding direction Z3 is from the first bevel area 11 and the second bevel area 21 towards the inside of the top cover 20 during welding. For example, welding along the butt joint towards the direction of the top cover 20, and the weld pool bottom 100a is located on the top cover 20 after welding. In this way, when welding defects such as pores are generated at the weld pool bottom 100a after welding, the welding defects are located in the top cover 20. When the shell 10 is stressed, the welding defects are not between the shell 10 and the top cover 20, which can reduce the possibility of cracks generated on the shell 10 due to stress concentration, reduce the damage to the shell 10, and improve the welding structure strength of the battery cell 100.

[0069] The manufacturing method of the embodiment can reduce the adverse effect caused by the defect of the molten pool bottom 100a, reduce the damage to the strength of the shell 10 caused by the stress concentration point generated by the external force, and improve the welding structure strength of the battery cell 100.

[0070] In some embodiments, referring to FIGS. 2-7, the first beveled edge area 11 is an inner beveled edge area, and the top cover 20 has a first straight edge area 22 connected with the second beveled edge area 21, and the first straight edge area 22 is connected with the inner side wall 14 of the shell 10.

[0071] The shell 10 has an inner side wall 14 and an outer side wall 15, and the inner side wall 14 of the shell 10 refers to the side wall facing the accommodating cavity of the shell 10, and the outer side wall 15 of the shell 10 refers to the side wall on the outer periphery of the shell 10.

[0072] The top cover 20 has an upper surface 24 and a lower surface 25, and the upper surface 24 of the top cover 20 refers to the top surface, and the lower surface 25 of the top cover 20 refers to the surface facing the accommodating cavity of the shell 10.

[0073] It can be understood that when the first beveled edge area 11 is an inner beveled edge area, the direction of the joint seam is downward relative to the horizontal direction when the joint seam is from the outside of the top cover 20 and the shell 10 to the inside of the top cover 20. That is, the first beveled edge area 11 and the inner side wall 14 of the shell 10 form an obtuse angle in the direction of the inside of the structure of the shell 10. In the cross section of the shell 10 and the top cover 20, the outer end point D1 of the joint line L1 can be located on the top surface of the top cover 20 or on the side surface of the shell 10.

[0074] In this embodiment, when the top cover 20 and the shell 10 are welded, the position where the first beveled edge area 11 and the second beveled edge area 21 are butted can be aligned above the battery cell 100 for welding, so as to improve the welding quality. The molten pool bottom 100a generated by the welding of the shell 10 and the top cover 20 is located on the top cover 20, which can reduce the adverse effect caused by the defect of the molten pool bottom 100a, reduce the damage to the strength of the shell 10 caused by the stress concentration point generated by the external force, and thus improve the welding structure strength of the battery cell 100. The first straight edge area 22 of the top cover 20 is connected with the inner side wall 14 of the shell 10, which facilitates the adjustment of the position and range of the molten pool bottom 100a, reduces the possibility that the molten pool bottom 100a is located outside the top cover 20, and also helps to improve the welding structure strength of the battery cell.

[0075] In some embodiments, referring to Figs. 2-4, the first bevel edge region 11 is an inner bevel edge region, and the top cover 20 has a first straight edge region 22 connected with the second bevel edge region 21, and the first straight edge region 22 is connected with the inner side wall 14 of the shell 10. The open end of the shell 10 has a second straight edge region 12 connected with the first bevel edge region 11, and the second straight edge region 12 is flush with the upper surface 24 of the top cover 20.

[0076] The shell 10 has the second straight edge region 12 formed on the outer circumferential surface, and the second straight edge region 12 of the shell 10 is connected with the outer side wall 15 to form a right angle. Correspondingly, in the cross section of the shell 10 and the top cover 20, the second bevel edge region 21 and the upper surface 24 of the top cover 20 form an acute angle towards the inside of the top cover 20.

[0077] In this embodiment, when the top cover 20 and the shell 10 are welded, the second straight edge region 12 can be positioned, which facilitates the welding operation.

[0078] Exemplarily, the length of the straight edge formed by the second straight edge region 12 on the cross section of the shell 10 and the top cover 20 is not more than one half of the thickness of the shell 10, which facilitates the positioning of the second straight edge region 12 during welding.

[0079] It should be noted that the length of the straight edge formed by the second straight edge region 12 on the cross section of the shell 10 and the top cover 20 refers to the length of the second straight edge region 12 along the thickness direction of the shell 10.

[0080] In some embodiments, referring to Figs. 5-7, the first bevel edge region 11 is an inner bevel edge region, and the top cover 20 has a first straight edge region 22 connected with the second bevel edge region 21, and the first straight edge region 22 is connected with the inner side wall 14 of the shell 10. The top cover 20 has a third straight edge region 23 connected with the second bevel edge region 21, and the third straight edge region 23 is flush with the outer side wall of the shell 10.

[0081] The top cover 20 has the third straight edge region 23 formed on the outer circumferential surface, and in the cross section of the shell 10 and the top cover 20, the first bevel edge region 11 and the outer side wall 15 form an acute angle towards the inside of the shell 10. The outer end point D1 of the connecting line L1 is located on the outer side wall 15 of the shell 10. In this way, the top cover 20 can be arranged on the shell 10, and the stability of the connection between the shell 10 and the top cover 20 can be improved. Meanwhile, when the top cover 20 and the shell 10 are welded, the third straight edge region 23 can be positioned, which facilitates the welding operation.

[0082] In some embodiments, referring to Figs. 8-16, the first bevel edge region 11 is an outer bevel edge region, and the top cover 20 has a third straight edge region 23 connected with the second bevel edge region 21, and the third straight edge region 23 is flush with the outer side wall of the shell 10.

[0083] It can be understood that when the first bevel region 11 is an outer bevel region, the direction of the butt joint is upward relative to the horizontal direction when the butt joint is from the outside of the top cover 20 and the shell 10 to the inside of the top cover 20. That is, the first bevel region 11 and the outer side wall 15 form an obtuse angle in the direction of the inside of the shell 10 structure. In the cross section of the shell 10 and the top cover 20, the outer end point D1 of the butt joint line L1 is located at the outer side wall 15 of the shell 10. In this way, the top cover 20 can be covered on the shell 10, and the stability of the connection of the shell 10 and the top cover 20 can be improved.

[0084] It can be understood that when the first bevel region 11 is an outer bevel region, the shell 10 and the top cover 20 are welded, and the battery cell can be placed at an angle suitable for welding according to the welding operation requirements, for example, the battery cell is turned over, the outer end point D1 of the butt joint line L1 is upward, so as to facilitate the operation of the welding tool during welding and the selection of a suitable welding direction Z3.

[0085] Exemplarily, referring to FIGS. 8-10, the second bevel region 21 is connected with the lower surface 25 of the top cover 20 and the third straight edge region 23, respectively. In the cross section of the shell 10 and the top cover 20, the inner end point D2 of the butt joint line L1 is located at the intersection of the lower surface 25 and the inner side wall 14, and the bottom 100a of the molten pool formed by welding is located in the top cover 20.

[0086] Exemplarily, referring to FIGS. 11-13, the top cover 20 has a first straight edge region 22 flush with the inner side wall 14 of the shell 10, and the second bevel region 21 is connected with the first straight edge region 22 and the third straight edge region 23, respectively. In the cross section of the shell 10 and the top cover 20, the inner end point D2 of the butt joint line L1 is located at the intersection of the first straight edge region 22 and the second bevel region 21, and the bottom 100a of the molten pool formed by welding is located in the top cover 20.

[0087] The first straight edge region 22 of the top cover 20 is connected with the inner side wall 14 of the shell 10, which is convenient for adjusting the position and range of the molten pool bottom, and also helps to improve the welding structural strength of the battery cell 100.

[0088] In some embodiments, referring to FIGS. 14-16, the first bevel region 11 is an outer bevel region, the top cover 20 has a third straight edge region 23 connected with the second bevel region 21, and the third straight edge region 23 is flush with the outer side wall of the shell 10. The shell 10 has a second straight edge region 12 connected with the first bevel region 11, and the second straight edge region 12 is connected with the lower surface 25 of the top cover 20.

[0089] The lower surface 25 of the top cover 20 extends towards the shell 10 and is adapted to the second straight edge area 12. In the cross section of the shell 10 and the top cover 20, the first bevel edge area 11 and the second straight edge area 12 of the shell 10 form an obtuse angle towards the inside of the shell 10, and the lower surface 25 and the second bevel edge area 21 of the top cover 20 also form an obtuse angle towards the shell 10. In this way, the top cover 20 can be arranged on the shell 10, and the stability of the connection between the shell 10 and the top cover 20 can be improved. The second straight edge area 12 is connected to the lower surface 25 of the top cover 20, which facilitates adjustment of the position and range of the bottom of the molten pool.

[0090] In some embodiments, the inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are both 15°-75° relative to the horizontal direction.

[0091] The inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are both α relative to the horizontal direction, and α can be 15°, 18°, 20°, 22°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 70°, 72° or 75°, etc.

[0092] In this embodiment, the inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are controlled to be 15°-75°, which facilitates assembly of the shell 10 and the top cover 20 before welding, and reduces the possibility of the bottom 100a of the molten pool being located outside the top cover 20, thereby improving the structural strength of the welded structure of the battery cell 100.

[0093] In some embodiments, the inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are both 40°-60° relative to the horizontal direction.

[0094] The inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are both β relative to the horizontal direction, and β can be 40°, 42°, 44°, 46°, 48°, 50°, 52°, 54°, 56°, 58° or 60°, etc.

[0095] In this embodiment, the inclination angle of the first bevel edge area 11 and the inclination angle of the second bevel edge area 21 are controlled to be 40°-60°, which facilitates assembly of the shell 10 and the top cover 20 before welding, and further reduces the possibility of the bottom 100a of the molten pool being located outside the top cover 20, thereby improving the structural strength of the welded structure of the battery cell 100.

[0096] In some embodiments, the manufacturing method comprises: providing the shell 10, so that the shell 10 has an open end, and the shell 10 has a first beveled edge area 11 at the open end; providing the top cover 20, so that the top cover 20 has a second beveled edge area 21, and the second beveled edge area 21 is adapted to the inclination angle of the first beveled edge area 11; fitting the top cover 20 to the open end of the shell 10, so that the second beveled edge area 21 and the first beveled edge area 11 abut to form an abutment seam, and the extension direction of the abutment seam is towards the top cover 20; and welding the top cover 20 and the shell 10 along the abutment seam, so that the bottom 100a of the molten pool after welding is located on the top cover 20. In this embodiment, the first beveled edge area 11 is an inner beveled edge area, the top cover 20 has a first straight edge area 22 connected to the second beveled edge area 21, and the first straight edge area 22 abuts to the inner side wall of the shell 10; the open end of the shell 10 has a second straight edge area 12 connected to the first beveled edge area 11, and the second straight edge area 12 is flush with the upper surface 24 of the top cover 20; the inclination angle of the first beveled edge area 11 and the inclination angle of the second beveled edge area 21 are both 50° relative to the horizontal direction; the materials of the shell 10 and the top cover 20 are both aluminum alloy, and the welding of the shell 10 and the top cover 20 is laser welding. In this embodiment, the bottom 100a of the molten pool generated by welding the shell 10 and the top cover 20 is located on the top cover 20, which can reduce the adverse effects caused by defects in the bottom 100a of the molten pool, reduce the damage to the strength of the shell 10 caused by stress concentration points generated by external forces, and improve the welding structural strength of the battery cell 100.

[0097] A second aspect of the embodiments of the present disclosure aims to provide a battery cell 100, which comprises a shell 10 and a top cover 20. The shell 10 has an open end, and the top cover 20 is fitted to the open end of the shell 10. The shell 10 and the top cover 20 are welded, so that the bottom 100a of the molten pool after welding is located on the top cover 20.

[0098] The bottom 100a of the molten pool can be obtained by measuring and analyzing the welding section, for example, by crystal phase analysis. The bottom 100a of the molten pool is located on the top cover 20, which reduces the adverse effects of stress concentration caused by external forces on the shell 10.

[0099] In some embodiments, the thickness of the region of the top cover 20 close to the shell 10 is greater than the thickness of the region of the shell 10 close to the top cover 20.

[0100] It should be noted that the thickness of the top cover 20 refers to the thickness of the top cover 20 body in the up-down direction, and the thickness of the shell 10 refers to the thickness of the shell 10 body in the horizontal direction. The thickness of the top cover 20 and the thickness of the shell 10 do not include the part of the top cover 20 and the shell 10 abutting to form the abutment seam and the part of opening the hole slot.

[0101] For example, the thickness of the region of the top cover 20 close to the shell 10 is greater than the thickness of the shell 10, which means that the size of the region of the top cover 20 greater than the thickness of the shell 10 is sufficient to generate the bottom 100a of the molten pool in the top cover 20.

[0102] The thickness of the top cover 20 near the shell 10 is greater than the thickness of the shell 10, the top cover 20 has a larger space to accommodate the molten pool bottom 100a, and the structural strength is better. The molten pool bottom 100a generated by welding the shell 10 and the top cover 20 is generated on the top cover 20, and compared with the molten pool bottom 100a generated on the shell 10, the damage caused by defects such as pores generated by the molten pool bottom 100a is smaller.

[0103] Exemplarily, the thickness of the top cover 20 along the vertical direction is uniform, the thickness of the shell 10 along the horizontal direction is uniform, and the thickness of the top cover 20 is greater than the thickness of the shell 10, so that the top cover 20 has better structural strength. The thickness of the top cover 20 and the thickness of the shell 10 do not include the part of the top cover 20 and the shell 10 that forms the butt joint and the part that forms the hole slot.

[0104] In some embodiments, the materials of the shell 10 and the top cover 20 are both aluminum alloy, and the welding of the shell 10 and the top cover 20 is laser welding.

[0105] In this embodiment, the influence of factors such as material properties and surface state of the shell 10 and the top cover 20 on the welding gap is considered. For example, the thermal expansion coefficient and surface roughness of the material may affect the welding quality, so the material needs to be properly pretreated before welding, such as cleaning and grinding, to improve the welding quality. The materials of the shell 10 and the top cover 20 are aluminum alloy, which can improve the strength of the battery cell.

[0106] The use of laser welding can improve the positioning accuracy, improve the welding quality, and improve the connection strength and structural stability of the shell 10 and the top cover 20. First, laser welding has the characteristics of fast heating and energy concentration, which can quickly heat the welding object to the melting point and form a welding joint. At the same time, due to the very short welding time, the thermal damage to the welding object is very small, so the precision and strength of the welding point are higher. Second, laser welding can also realize precise connection of components, and can provide high-quality welding seams, thereby improving the stability and reliability of the battery. In addition, laser welding also has the advantages of fast welding speed and high automation degree, which can improve production efficiency and reduce production cost. At the same time, the welding seam of laser welding is beautiful, stable, corrosion-resistant and durable, which helps to improve the overall quality of the battery.

[0107] The third aspect of the embodiments of the present disclosure aims to provide a shell 10, which is provided in any of the above manufacturing methods. The shell 10 has an open end, and the shell 10 has a first beveled edge region 11 at the open end. After the top cover 20 is fitted to the open end of the shell 10, the extension direction of the first beveled edge region 11 is towards the inside of the top cover 20. The shell 10 and the top cover 20 are welded along the first beveled edge region 11, and the molten pool bottom 100a after welding is located on the top cover 20.

[0108] A fourth aspect of the embodiments of the present disclosure provides a top cover 20, which is provided by any one of the manufacturing methods described above. The top cover 20 has a second bevel region 21. The extending direction of the second bevel region 21 is towards the inside of the top cover 20. After the top cover 20 is fitted to the open end of the shell 10, the shell 10 and the top cover 20 are welded along the second bevel region 21, and the bottom 100a of the molten pool after welding is located on the top cover 20. A fifth aspect of the embodiments of the present disclosure provides an electric device, which includes the battery cell 100 manufactured by any one of the manufacturing methods described above, and is used to provide electric energy; or includes the battery cell 100 described in any one of the manufacturing methods described above, and is used to provide electric energy.

[0109] The electric device includes, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric automobile, a ship, a spacecraft, etc. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric automobile toy, an electric ship toy, an electric aircraft toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, etc.

[0110] The various embodiments / implementation forms provided by the present disclosure can be combined with each other without producing contradictions, if necessary.

[0111] The above merely describes the preferred embodiments of the present disclosure, but is not intended to limit the present disclosure. The present disclosure can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for manufacturing an electric cell, comprising: providing a shell, such that the shell has an open end, and the shell has a first bevel region at the open end; providing a top cover, such that the top cover has a second bevel region, and the second bevel region is adapted to the angle of inclination of the first bevel region; fitting the top cover to the open end of the shell, such that the second bevel region and the first bevel region meet to form a butt joint, and the extension direction of the butt joint is towards the top cover; welding the top cover to the shell along the butt joint, such that the bottom of the weld pool after welding is located on the top cover.

2. The method of manufacturing an electrical cell according to claim 1, wherein, The first bevel region is an inner bevel region, and the top cover has a first straight region connected to the second bevel region, and the first straight region meets the inner side wall of the shell.

3. The method of manufacturing an electrical cell according to claim 2, wherein, The open end of the shell has a second straight region connected to the first bevel region, and the second straight region is flush with the upper surface of the top cover.

4. The method of manufacturing an electric chip according to claim 2 or 3, wherein The top cover has a third straight region connected to the second bevel region, and the third straight region is flush with the outer side wall of the shell.

5. The method of manufacturing an electrical cell of claim 1, wherein, The first bevel region is an outer bevel region, and the top cover has a third straight region connected to the second bevel region, and the third straight region is flush with the outer side wall of the shell.

6. The method of manufacturing an electrical cell according to claim 5, wherein, The shell has a second straight region connected to the first bevel region, and the second straight region meets the lower surface of the top cover.

7. The method of manufacturing an electric chip according to any one of claims 1 to 6, wherein The angle of inclination of the first bevel region and the angle of inclination of the second bevel region are both 15°-75° with respect to the horizontal direction.

8. The method of manufacturing an electrical cell according to claim 7, wherein, The angle of inclination of the first bevel region and the angle of inclination of the second bevel region are both 40°-60° with respect to the horizontal direction. 9.An electric cell, comprising: a shell, the shell having an open end; a top cover, the top cover being fitted to the open end of the shell, and the top cover being welded to the shell, and the bottom of the weld pool after welding being located on the top cover.

10. The electric cell of claim 9, wherein, The thickness of the region of the top cover close to the shell is greater than the thickness of the region of the shell close to the top cover.

11. The electric cell of claim 9 or 10, wherein, The materials of the shell and the top cover are both aluminum alloy, and the welding of the shell and the top cover is laser welding. 12.A shell, provided in the method for manufacturing an electric cell according to any one of claims 1 to 8. 13.A top cover, provided in the method for manufacturing an electric cell according to any one of claims 1 to 8. 14.An electric device, comprising an electric cell manufactured according to the method for manufacturing an electric cell according to any one of claims 1 to 8, for providing electric energy; or, comprising an electric cell according to any one of claims 9 to 11, for providing electric energy.

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