Forming die and battery cell manufacturing system

Abstract

A forming die and a battery cell manufacturing system. The forming die is used for casing forming of battery cells, and the forming die comprises a die and a punch. The die is provided with a through hole, and the punch mates with the through hole to press a piece to be machined. The punch has a first outer side surface; the first outer side surface comprises a first surface and a second surface which are sequentially distributed in a first direction; the first direction is the stamping direction of the punch; the second surface is configured to enter the through hole before the first surface in the first direction; the second surface protrudes from the first surface in a second direction; and the second direction is perpendicular to the first direction. Using the forming die to manufacture casings can improve the reliability of battery cells.

Description

Molding mold and battery cell manufacturing system CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application CN2024202923570, entitled “Molding Mold and Battery Cell Manufacturing System,” filed on February 18, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery manufacturing technology, and in particular to a molding die and a battery cell manufacturing system. Background Art

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0004] During the manufacturing process of batteries, battery reliability is an issue that cannot be ignored. Therefore, how to improve battery reliability is a technical problem that needs to be solved urgently in battery technology. Summary of the Invention

[0005] The present application provides a molding die and a battery cell manufacturing system, which can improve the reliability of battery cells.

[0006] This application is achieved through the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a forming mold for forming a battery cell shell, the forming mold comprising a die and a punch. The die has a through hole; the punch is used to press the workpiece to be processed into the through hole, so as to cooperate with the through hole to extrude the workpiece to be processed. The punch has a first outer side surface, the first outer side surface comprising a first surface and a second surface sequentially distributed along a first direction, the first direction being the punching direction of the punch, the second surface being configured to enter the through hole before the first surface along the first direction, and protrude from the first surface along the second direction, and the second direction is perpendicular to the first direction.

[0008] According to the forming mold of the embodiment of the present application, the workpiece to be processed is extruded through the cooperation of the punch and the through hole, which facilitates the processing and manufacturing of the shell; the second surface protrudes from the first surface, so that the opening of the structure after the workpiece to be processed is thickened, thereby improving the strength of the shell at the opening after molding, reducing the risk of cracking of the shell near the welding position between the shell and the end cover, and improving the reliability of the battery cell.

[0009] According to some embodiments of the present application, the through hole has a first inner side surface, and when the punch is engaged with the through hole, the first inner side surface is opposite to the first outer side surface in the second direction; along the first direction, the first inner side surface includes a third surface and a fourth surface connected in sequence, and when the punch is engaged with the through hole, the third surface engages with the punch before the fourth surface; along the first direction, the distance between the third surface and the second surface in the second direction gradually decreases.

[0010] In the above solution, the distance between the third surface and the second surface in the second direction gradually decreases to facilitate guiding the punch head.

[0011] According to some embodiments of the present application, the first inner side surface further includes a fifth surface. Along the first direction, the third surface, the fourth surface and the fifth surface are sequentially connected, and the distance between the fifth surface and the second surface in the second direction gradually increases.

[0012] In the above solution, the distance between the fifth surface and the second surface in the second direction gradually increases, so as to facilitate the flow of the material during stamping and release stress.

[0013] According to some embodiments of the present application, the first outer side surface further includes a transition surface, and along the first direction, the first surface, the transition surface and the second surface are distributed in sequence; along the first direction, the size of the transition surface protruding from the first surface gradually increases.

[0014] In the above solution, the provision of the transition surface can facilitate the demoulding of the punch and reduce the damage of the punch to the workpiece.

[0015] According to some embodiments of the present application, the transition surface is a plane, and the angle between the transition surface and the plane where the second surface is located is θ, satisfying 3°≤θ≤60°.

[0016] In the above scheme, the angle between the transition surface and the plane where the second surface is located satisfies the above range. On the one hand, when θ≥3°, the processing and molding resistance is small and the demolding resistance is small. On the other hand, when θ≤60°, the size of the transition surface in the second direction is small, reducing the space occupied at the corresponding position of the first surface after the shell is formed, so that the battery cell can have a higher energy density.

[0017] According to some embodiments of the present application, 20°≤θ≤40°.

[0018] In the above scheme, compared with θ<20°, when θ≥20°, the demolding resistance is further reduced, and the damage to the workpiece by the punch is reduced; compared with θ>40°, when θ≤40°, the size of the transition surface in the second direction is smaller, further reducing the space occupied at the corresponding position of the first surface after the shell is formed.

[0019] According to some embodiments of the present application, the transition surface transitions to the first surface via a first arc surface, and the transition surface transitions to the second surface via a second arc surface.

[0020] In the above solution, the transition surface and the first surface transition through the first arc surface, and the transition surface and the second surface transition through the second arc surface, which reduces the scratching of the punch on the workpiece during demoulding and facilitates demoulding.

[0021] According to some embodiments of the present application, the radius of the first arc surface is R1, satisfying 0.05mm≤R1≤0.4mm; and / or the radius of the second arc surface is R2, satisfying 0.05mm≤R2≤0.4mm.

[0022] In the above scheme, the radius of the first arc surface satisfies the above relationship, and / or the radius of the second arc surface satisfies the above relationship. On the one hand, when R1 ≥ 0.05 mm and / or R2 ≥ 0.05 mm, the processing difficulty is relatively low. On the other hand, when R1 ≤ 0.4 mm and / or R2 ≤ 0.4 mm, the damage caused by the punch to the workpiece is reduced, and the damage to the punch during demolding is reduced, thereby improving the life of the punch.

[0023] According to some embodiments of the present application, 0.08 mm ≤ R1 ≤ 0.12 mm; and / or, 0.08 mm ≤ R2 ≤ 0.12 mm.

[0024] In the above scheme, compared with R1 < 0.08mm, when R1 ≥ 0.08mm, the processing difficulty is further reduced; compared with R1 > 0.12mm, when R1 ≤ 0.12mm, the damage to the workpiece by the punch is further reduced, the damage to the punch during demolding is reduced, and the life of the punch is further improved. Compared with R2 < 0.08mm, when R2 ≥ 0.08mm, the processing difficulty is further reduced; compared with R2 > 0.12mm, when R2 ≤ 0.12mm, the damage to the workpiece by the punch is further reduced, the damage to the punch during demolding is reduced, and the life of the punch is further improved.

[0025] According to some embodiments of the present application, the surface roughness of the first arc surface is Ra1, satisfying 0.01mm≤Ra1≤0.1mm; and / or the surface roughness of the second arc surface is Ra2, satisfying 0.01mm≤Ra2≤0.1mm.

[0026] In the above scheme, the surface roughness of the first arc surface meets the above requirements, and / or the surface roughness of the second arc surface meets the above requirements. On the one hand, when Ra1≥0.01mm and / or Ra2≥0.01mm, the scratching of the punch on the workpiece during demolding is reduced, which facilitates demolding. On the other hand, when Ra1≤0.1mm and / or Ra2≤0.1mm, the processing and manufacturing difficulty is low and the processing cost is low.

[0027] According to some embodiments of the present application, 0.03 mm ≤ Ra1 ≤ 0.07 mm; and / or, 0.03 mm ≤ Ra2 ≤ 0.07 mm.

[0028] In the above scheme, compared with Ra1 < 0.03mm, when Ra1 ≥ 0.03mm, the difficulty of processing and manufacturing is further reduced, and the processing cost is reduced; compared with Ra1 > 0.07mm, when Ra1 ≤ 0.07, the scratching of the punch on the workpiece during demolding is further reduced, which facilitates demolding. Compared with Ra2 < 0.03mm, when Ra2 ≥ 0.03mm, the difficulty of processing and manufacturing is further reduced, and the processing cost is reduced; compared with Ra2 > 0.07mm, when Ra2 ≤ 0.07, the scratching of the punch on the workpiece during demolding is further reduced, which facilitates demolding.

[0029] According to some embodiments of the present application, there are two first outer side surfaces, and the two first outer side surfaces are arranged opposite to each other in the second direction; the punch also has two second outer side surfaces arranged opposite to each other in the third direction, the third direction, the second direction and the first direction are perpendicular to each other, and the area of ​​the second outer side surfaces is smaller than that of the first outer side surfaces.

[0030] In the above scheme, the number of the first outer side surfaces is two, which facilitates the molding of the shell; the area of ​​the second outer side surface is smaller than that of the first outer side surface, and the first outer side surface can be used to mold the large surface of the shell, which can reduce the risk of cracking of the shell in the area near the welding position between the shell and the end cover.

[0031] According to some embodiments of the present application, the second outer side surface includes a sixth surface and a seventh surface sequentially distributed along the first direction, and along the third direction, the seventh surface protrudes from the sixth surface.

[0032] In the above solution, the opening of the wall of the shell corresponding to the second outer side surface is thickened to further reduce the risk of the shell cracking in the area near the welding position between the shell and the end cover.

[0033] According to some embodiments of the present application, the punch also has a corner surface, which connects the adjacent first outer side surface and the second outer side surface. The corner surface includes an eighth surface and a ninth surface distributed in sequence along the first direction. The eighth surface and the ninth surface are both arc surfaces. Along the radial direction of the arc surface, the ninth surface protrudes from the eighth surface.

[0034] In the above solution, the corners of the punch are thickened so that after the shell is formed, the corners of the shell can be thickened to enhance the strength of the shell and reduce the risk of shell cracking.

[0035] According to some embodiments of the present application, the through hole has a first inner side surface, and when the punch is engaged with the through hole, the first inner side surface is opposite to the first outer side surface in the second direction; the dimension d of the second surface protruding from the first surface is greater than or equal to 0.1 times the minimum distance D between the second surface and the first inner side surface, and the dimension d of the second surface protruding from the first surface is less than or equal to 0.8 times the minimum distance D between the second surface and the first inner side surface.

[0036] In the above scheme, on the one hand, the larger d is (or the smaller D is), the thicker the opening of the shell formed after the punch and the through hole are, and the higher the strength of the shell opening is. When the dimension d of the second surface protruding from the first surface is greater than or equal to 0.1 times the minimum distance D between the second surface and the first inner side surface, the thickness of the shell at the corresponding position of the first surface after molding is thicker, and the strength here is higher, reducing the risk of the shell cracking near the welding area between the shell and the end cover; on the other hand, d is small (or D is large), the dimension of the second surface protruding from the first surface is small, and when the workpiece to be processed and the punch are demolded, the force exerted by the punch on the workpiece to be processed is small. When the dimension d of the second surface protruding from the first surface is less than or equal to 0.8 times the minimum distance D between the second surface and the first inner side surface, the risk of the workpiece to be processed being pulled apart can be reduced.

[0037] According to some embodiments of the present application, the dimension d of the second surface protruding from the first surface is greater than or equal to 0.3 times the minimum distance D between the second surface and the first inner side surface, and the dimension d of the second surface protruding from the first surface is less than or equal to 0.5 times the minimum distance D between the second surface and the first inner side surface.

[0038] In the above scheme, compared with d / D < 30%, when d / D ≥ 30%, the thickness of the shell at the position corresponding to the first surface after molding is further increased to improve the strength there; compared with d / D > 50%, when d / D ≤ 50%, the risk of cracking of the workpiece to be processed is further reduced.

[0039] According to some embodiments of the present application, the punch includes a base and a coating provided on the surface of the base. The base is made of steel, and the coating is made of titanium aluminum chromium nitride, chromium aluminum nitride, or titanium aluminum nitride.

[0040] In the above solution, the material of the substrate is steel, and the substrate has high strength; the surface of the substrate is provided with a coating, which can improve the wear resistance of the punch and extend the service life of the punch.

[0041] In a second aspect, an embodiment of the present application further provides a battery cell manufacturing system, which includes a plurality of molding dies as provided in any of the above embodiments, and the plurality of molding dies are used for a plurality of molding processes of the shell.

[0042] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0044] FIG1 is an exploded schematic diagram of a forming mold provided in some embodiments of the present application;

[0045] FIG2 is a perspective view of a punch provided in some embodiments of the present application;

[0046] FIG3 is a schematic structural diagram of a first outer side surface of a punch provided in some embodiments of the present application;

[0047] FIG4 is a partial enlarged view of point A in FIG3 ;

[0048] FIG5 is a schematic diagram of the cooperation between the punch and the through hole provided in some embodiments of the present application;

[0049] FIG6 is a schematic structural diagram of a punch provided in some embodiments of the present application;

[0050] FIG7 is a partial enlarged view of point B in FIG6;

[0051] FIG8 is a schematic diagram of a base and a coating of a punch provided in some embodiments of the present application;

[0052] FIG9 is a schematic diagram of a punch and a die cooperating to form a housing according to some embodiments of the present application;

[0053] FIG10 is a schematic structural diagram of a housing formed by cooperation between a punch and a die according to some embodiments of the present application;

[0054] FIG11 is a cross-sectional view of a housing formed by cooperation between a punch and a die according to some embodiments of the present application;

[0055] FIG12 is a partial enlarged view of point C in FIG11;

[0056] FIG13 is a partial schematic diagram of a second wall provided in some embodiments of the present application;

[0057] In the drawings, the drawings are not drawn to scale.

[0058] Marking instructions: 100-forming mold; 10-die; 11-through hole; 111-first inner side surface; 111a-third surface; 111b-fourth surface; 111c-fifth surface; 20-punch; 21-first outer side surface; 211-first surface; 212-second surface; 213-transition surface; 214-first arc surface; 215-second arc surface; 22-second outer side surface; 221-sixth surface; 222-seventh surface; 23-corner surface; 231-eighth surface; 232-ninth surface; 24-base; 25-plating; 26-lower end surface; 30-shell; 31-first wall; 311-first area; 312-second area; 32-second wall; 321-third area; 322-fourth area; 33-bottom wall; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0059] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0060] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0061] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0062] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0063] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0064] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0065] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0066] The battery cells may be, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0067] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, or a composite metal housing (e.g., a copper-aluminum composite housing).

[0068] In some embodiments, the housing includes an end cap and a shell. The shell has an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other substances. The shell may have one or more openings. One or more end caps may also be provided.

[0069] The development of battery technology must take into account multiple design factors at the same time, such as energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0070] In some embodiments, the housing can be formed by stamping, for example, a punch and a die cooperate to squeeze the workpiece to be processed, so that the workpiece is formed into the housing. However, the wall portion of the housing is generally a uniform thickness structure. When the energy density of the battery cell is increased by reducing the wall thickness of the housing, after the housing and end cap are welded, a heat-affected zone is formed near the welding point between the housing and the end cap, which reduces the strength of the housing and the end cap in this area, making the housing prone to cracking in the area near the welding point between the housing and the end cap, thereby reducing the reliability of the battery cell.

[0071] In view of this, in order to solve the problem that the shell is prone to cracking in the area near the welding position between the shell and the end cover, resulting in low reliability of the battery cell, an embodiment of the present application provides a technical solution, in which a forming mold is used to form the shell of the battery cell, and the first outer side surface of the punch includes a first surface and a second surface distributed in sequence along a first direction. The first surface is the stamping direction of the punch, and along the second direction, the second surface protrudes from the first surface, and the second direction is perpendicular to the first direction. After the workpiece to be processed is extruded by the punch and the through hole, the thickness of the opening of the formed structure is thicker and the strength of the opening is higher, which can improve the reliability of the battery cell.

[0072] During the molding process, the first surface corresponds to the opening position of the structure after the workpiece is extruded, and the second surface protrudes from the first surface, so that the structure after the workpiece is extruded is thicker at the opening, which can improve the strength at the opening. After the shell and the end cover are welded, the risk of cracking of the shell in the area near the welding position of the shell and the end cover can be reduced, thereby improving the reliability of the battery cell.

[0073] The battery manufactured by the molding mold disclosed in the embodiment of the present application can be used, but not limited to, in electrical equipment such as vehicles, ships or aircraft. The battery disclosed in the present application can be used to form a power supply system for the electrical equipment.

[0074] The forming mold provided in the embodiments of the present application is described below with reference to the accompanying drawings.

[0075] Please refer to Figures 1 to 4. Figure 1 is an exploded schematic diagram of a forming mold provided in some embodiments of the present application. Figure 2 is a perspective view of a punch provided in some embodiments of the present application. Figure 3 is a schematic structural diagram of the first outer side surface of the punch provided in some embodiments of the present application. Figure 4 is an enlarged partial view of point A in Figure 3. Embodiments of the present application provide a forming mold 100 for forming battery cell housings. The forming mold 100 includes a die 10 and a punch 20. The die 10 has a through hole 11. The punch 20 is used to press a workpiece into the through hole 11, thereby cooperating with the through hole 11 to compress the workpiece. The punch 20 has a first outer side surface 21. The first outer side surface 21 includes a first surface 211 and a second surface 212 arranged sequentially along a first direction X. The first direction X is the punching direction of the punch 20. The second surface 212 is configured to enter the through hole 11 before the first surface 211 along the first direction X. The second surface 212 protrudes from the first surface 211 along a second direction Y. The second direction Y is perpendicular to the first direction X.

[0076] In the figure, the direction indicated by the letter X is the first direction. The punching direction of the punch 20 is the direction in which the punch 20 enters the through hole 11. The direction indicated by the letter Y is the second direction.

[0077] The die 10 provides space for a punch 20. The punch 20 cooperates with the die 10 to compress the workpiece to obtain a predetermined structure. For example, the punch 20 approaches the workpiece along a first direction X and squeezes at least a portion of the workpiece into the through hole 11 of the die 10. The punch 20 engages the wall of the through hole 11, thereby forming the workpiece into a predetermined structure.

[0078] The through hole 11 is a hole of the die 10 for cooperating with the punch 20 and is used for the punch 20 to be inserted to extrude the workpiece to be processed.

[0079] The first outer side surface 21 refers to a side surface of the punch 20 for engaging with the through hole 11 .

[0080] The first surface 211 and the second surface 212 are sequentially distributed along the first direction X. After the punch 20 cooperates with the through hole 11 to extrude the workpiece, the first surface 211 corresponds to the opening of the structure after the workpiece is extruded.

[0081] Along the second direction Y, the second surface 212 protrudes from the first surface 211. During the molding process, along the second direction Y, the second surface 212 is closer to the wall of the through-hole 11 than the first surface 211. During the molding process, the thickness of the structure squeezed by the second surface 212 and the wall of the through-hole 11 is relatively thin, while the thickness of the structure squeezed by the first surface 211 and the wall of the through-hole 11 is relatively thick.

[0082] According to the molding die 100 of the embodiment of the present application, the workpiece to be processed is extruded through the cooperation of the punch 20 and the through hole 11, which facilitates the processing and manufacturing of the shell; the second surface 212 protrudes from the first surface 211, so that the opening of the structure after the workpiece to be processed is thickened, thereby improving the strength of the shell at the opening after molding, reducing the risk of cracking of the shell near the welding position between the shell and the end cover, and improving the reliability of the battery cell.

[0083] Please refer to Figure 5, which is a schematic diagram illustrating the mating state of a punch and a through hole provided in some embodiments of the present application. According to some embodiments of the present application, the through hole 11 has a first inner side surface 111. When the punch 20 is mated with the through hole 11, the first inner side surface 111 and the first outer side surface 21 are opposite each other in the second direction Y. Along the first direction X, the first inner side surface 111 includes a third surface 111a and a fourth surface 111b connected in sequence. When the punch 20 is mated with the through hole 11, the third surface 111a mates with the punch 20 before the fourth surface 111b. Along the first direction X, the distance between the third surface 111a and the second surface 212 in the second direction Y gradually decreases.

[0084] The third surface 111 a may be located at an opening position where the punch 20 enters the through hole 11 .

[0085] Stamping Process: As the punch 20 engages the through-hole 11, the second surface 212 first engages the third surface 111a. As the punch 20 moves, the second surface 212 gradually engages the fourth surface 111b. Simultaneously, as the punch 20 moves, the first surface 211 gradually engages the third and fourth surfaces 111a, 111b. During the stamping process, the fourth surface 111b, the second surface 212, and the first surface 211 mate to form the first wall 31 of the housing 30 (see Figure 12).

[0086] In the first direction X, the distance between the third surface 111a and the second surface 212 in the second direction Y gradually decreases from the end of the third surface 111a away from the fourth surface 111b to the end close to the fourth surface 111b, which is equivalent to that the opening of the through hole 11 near the third surface 111a is larger, so as to guide the punch 20 when the punch 20 enters the through hole 11.

[0087] In some embodiments, the fourth surface 111 b is parallel to the first direction X, and the fourth surface 111 b is a plane, so that the outer surface of the housing 30 corresponding to the fourth surface 111 b is a plane.

[0088] In the above solution, along the first direction X, the distance between the third surface 111 a and the second surface 212 in the second direction Y gradually decreases, so as to guide the punch 20 when the punch 20 enters the through hole 11 .

[0089] According to some embodiments of the present application, the first inner surface 111 further includes a fifth surface 111c. Along the first direction X, the third surface 111a, the fourth surface 111b and the fifth surface 111c are sequentially connected, and the distance between the fifth surface 111c and the second surface 212 in the second direction Y gradually increases.

[0090] The third surface 111 a , the fourth surface 111 b , and the fifth surface 111 c are sequentially distributed along the first direction X.

[0091] The fifth surface 111c and the third surface 111a may be located at both ends of the through hole 11 in the first direction X. For example, the fifth surface 111c may constitute another opening of the through hole 11. In the first direction X, the distance between the fifth surface 111c and the second surface 212 in the second direction Y gradually increases from the end of the fifth surface 111c closer to the fourth surface 111b to the end of the fifth surface 111c farther from the fourth surface 111b. The opening of the through hole 11 near the fifth surface 111c is larger, thereby facilitating the flow of material when the punch 20 engages with the through hole 11.

[0092] In the above solution, along the first direction X, the distance between the fifth surface 111 c and the second surface 212 in the second direction Y gradually increases, so as to facilitate the flow of the material during stamping and release stress.

[0093] Please refer to Figure 4. According to some embodiments of the present application, the first outer side surface 21 further includes a transition surface 213. Along the first direction X, the first surface 211, the transition surface 213 and the second surface 212 are distributed in sequence; along the first direction X, the size of the transition surface 213 protruding from the first surface 211 gradually increases.

[0094] Along the first direction X, the transition surface 213 is located between the first surface 211 and the second surface 212 . The transition surface 213 is used to connect the first surface 211 and the second surface 212 . The transition surface 213 realizes the transition from the first surface 211 to the second surface 212 .

[0095] “Along the first direction X, the size of the transition surface 213 protruding from the first surface 211 gradually increases” means that from the end of the transition surface 213 close to the first surface 211 to the end of the transition surface 213 close to the second surface 212, in the second direction Y, the size of the transition surface 213 protruding from the first surface 211 gradually increases.

[0096] In the above solution, the provision of the transition surface 213 can facilitate the demoulding of the punch 20 and reduce the damage of the punch 20 to the workpiece.

[0097] Referring to FIG. 4 , according to some embodiments of the present application, the transition surface 213 is a plane, and the angle between the transition surface 213 and the plane where the second surface 212 is located is θ, satisfying 3°≤θ≤60°.

[0098] In the figure, the angle indicated by θ is the acute angle between the transition surface 213 and the plane where the first surface 211 is located, that is, the angle between the extension plane of the first surface 211 and the transition surface 213 .

[0099] Alternatively, θ may be, but is not limited to, 3°, 6°, 9°, 12°, 15°, 18°, 21°, 24°, 27°, 30°, 33°, 36°, 39°, 42°, 45°, 48°, 51°, 54°, 57°, 60°, etc.

[0100] In the above scheme, the angle between the transition surface 213 and the plane where the second surface 212 is located satisfies the above range. On the one hand, when θ≥3°, the processing and molding resistance is small and the demolding resistance is small. On the other hand, when θ≤60°, the size of the transition surface 213 in the second direction Y is small, which reduces the space occupied at the corresponding position of the first surface 211 after the shell is formed, so that the battery cell can have a higher energy density.

[0101] According to some embodiments of the present application, 20°≤θ≤40°.

[0102] Alternatively, θ may be, but is not limited to, 20°, 22°, 24°, 26°, 28°, 30°, 32°, 34°, 36°, 38°, 40°, etc.

[0103] In the above scheme, compared with θ<20°, when θ≥20°, the demolding resistance is further reduced, and the damage to the workpiece to be processed by the punch 20 is reduced; compared with θ>40°, when θ≤40°, the size of the transition surface 213 in the second direction Y is smaller, further reducing the space occupied at the corresponding position of the first surface 211 after the shell 30 is formed.

[0104] 4 , according to some embodiments of the present application, the transition surface 213 transitions to the first surface 211 via a first arc surface 214 , and the transition surface 213 transitions to the second surface 212 via a second arc surface 215 .

[0105] The transition surface 213 transitions to the first surface 211 with a rounded corner, and the transition surface 213 transitions to the second surface 212 with a rounded corner.

[0106] In the above solution, the transition surface 213 transitions to the first surface 211 through the first arc surface 214, and the transition surface 213 transitions to the second surface 212 through the second arc surface 215, which reduces the scratching of the punch 20 on the workpiece during demolding and facilitates demolding.

[0107] 4 , according to some embodiments of the present application, the radius of the first arc surface 214 is R1, satisfying 0.05 mm ≤ R1 ≤ 0.4 mm; and / or the radius of the second arc surface 215 is R2, satisfying 0.05 mm ≤ R2 ≤ 0.4 mm.

[0108] Optionally, R1 may be, but is not limited to, 0.05 mm, 0.07 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.3 mm, 0.33 mm, 0.35 mm, 0.37 mm, 0.4 mm, etc.

[0109] Alternatively, R2 may be, but is not limited to, 0.05 mm, 0.07 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.3 mm, 0.33 mm, 0.35 mm, 0.37 mm, 0.4 mm, etc.

[0110] In the above scheme, the radius of the first arc surface 214 satisfies the above relationship, and / or the radius of the second arc surface 215 satisfies the above relationship. On the one hand, when R1 ≥ 0.05 mm and / or R2 ≥ 0.05 mm, the processing difficulty is relatively low. On the other hand, when R1 ≤ 0.4 mm and / or R2 ≤ 0.4 mm, the damage of the punch 20 to the workpiece to be processed is reduced, and the damage to the punch 20 during demolding is reduced, so as to improve the life of the punch 20.

[0111] According to some embodiments of the present application, 0.08 mm ≤ R1 ≤ 0.12 mm; and / or, 0.08 mm ≤ R2 ≤ 0.12 mm.

[0112] Optionally, R1 may be, but is not limited to, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, etc.

[0113] Optionally, R2 may be, but is not limited to, 0.08 mm, 0.09 mm, 0.1 mm, 0.11 mm, 0.12 mm, etc.

[0114] In the above solution, compared to R1 < 0.08 mm, when R1 ≥ 0.08 mm, the machining difficulty is further reduced; compared to R1 > 0.12 mm, when R1 ≤ 0.12 mm, the damage to the workpiece by the punch 20 is further reduced, the damage to the punch 20 during demolding is reduced, and the life of the punch 20 is further improved. Compared to R2 < 0.08 mm, when R2 ≥ 0.08 mm, the machining difficulty is further reduced; compared to R2 > 0.12 mm, when R2 ≤ 0.12 mm, the damage to the workpiece by the punch 20 is further reduced, the damage to the punch 20 during demolding is reduced, and the life of the punch 20 is further improved.

[0115] According to some embodiments of the present application, the surface roughness of the first arc surface 214 is Ra1, satisfying 0.01mm≤Ra1≤0.1mm; and / or the surface roughness of the second arc surface 215 is Ra2, satisfying 0.01mm≤Ra2≤0.1mm.

[0116] Surface roughness Ra1 and surface roughness Ra2 are both the arithmetic mean deviation of the profile.

[0117] The smaller the surface roughness value, the smoother the surface and the more difficult it is to process and manufacture.

[0118] Optionally, Ra1 may be, but is not limited to, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, etc.

[0119] Optionally, Ra2 may be, but is not limited to, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, etc.

[0120] In the above scheme, the surface roughness of the first arc surface 214 meets the above requirements, and / or the surface roughness of the second arc surface 215 meets the above requirements. On the one hand, when Ra1≥0.01mm and / or Ra2≥0.01mm, the scratching of the punch 20 on the workpiece during demolding is reduced, which facilitates demolding. On the other hand, when Ra1≤0.1mm and / or Ra2≤0.1mm, the processing and manufacturing difficulty is low and the processing cost is low.

[0121] According to some embodiments of the present application, 0.03 mm ≤ Ra1 ≤ 0.07 mm; and / or, 0.03 mm ≤ Ra2 ≤ 0.07 mm.

[0122] Optionally, Ra1 may be, but is not limited to, 0.03 mm, 0.035 mm, 0.04 mm, 0.045 mm, 0.05 mm, 0.055 mm, 0.06 mm, 0.065 mm, 0.07 mm, etc.

[0123] Optionally, Ra2 may be, but is not limited to, 0.03 mm, 0.035 mm, 0.04 mm, 0.045 mm, 0.05 mm, 0.055 mm, 0.06 mm, 0.065 mm, 0.07 mm, etc.

[0124] In the above solution, compared with Ra1 < 0.03mm, when Ra1 ≥ 0.03mm, the difficulty of processing and manufacturing is further reduced, and the processing cost is reduced; compared with Ra1 > 0.07mm, when Ra1 ≤ 0.07, the scratching of the punch 20 on the workpiece during demolding is further reduced, and demolding is facilitated. Compared with Ra2 < 0.03mm, when Ra2 ≥ 0.03mm, the difficulty of processing and manufacturing is further reduced, and the processing cost is reduced; compared with Ra2 > 0.07mm, when Ra2 ≤ 0.07, the scratching of the punch 20 on the workpiece during demolding is further reduced, and demolding is facilitated.

[0125] Please refer to Figure 2, and further to Figures 4 and 5. Figure 5 is a schematic diagram of the mating state of the punch and the through hole provided in some embodiments of the present application. According to some embodiments of the present application, the through hole 11 has a first inner side surface 111. When the punch 20 is mated with the through hole 11, the first inner side surface 111 and the first outer side surface 21 are opposite in the second direction Y. The dimension d of the second surface 212 protruding from the first surface 211 is greater than or equal to 0.1 times the minimum distance D between the second surface 212 and the first inner side surface 111, and the dimension d of the second surface 212 protruding from the first surface 211 is less than or equal to 0.8 times the minimum distance D between the second surface 212 and the first inner side surface 111.

[0126] d can be the height of the step formed by the first outer side surface 21 between the first surface 211 and the second surface 212, that is, the dimension by which the second surface protrudes from the first surface along the second direction. The larger d is, the greater the dimension by which the second surface 212 protrudes from the first surface 211, and the greater the thickness of the structure at the opening of the workpiece after being extruded. The smaller d is, the smaller the dimension by which the second surface 212 protrudes from the first surface 211, and the smaller the thickness of the structure at the opening of the workpiece after being extruded.

[0127] The first inner side surface 111 refers to a surface of the through hole 11 corresponding to the first outer side surface 21 , and the first inner side surface 111 and the first outer side surface 21 cooperate to extrude the workpiece to be processed.

[0128] D is the minimum distance between the second surface 212 and the first inner side surface 111 along the second direction Y when the punch 20 is engaged with the through hole 11. The larger D is, the greater the thickness of the workpiece between the second surface 212 and the first inner side surface 111; the smaller D is, the smaller the thickness of the workpiece between the second surface 212 and the first inner side surface 111.

[0129] The larger the d / D ratio, the larger d is or the smaller D is; the smaller d / D ratio, the smaller d is or the larger D is. For example, when d / D is larger, D remains unchanged and d becomes larger (or d remains unchanged and D becomes smaller), the thickness of the opening of the shell 30 (such as the first region 311, see FIG12 ) formed after the punch 20 and the through hole 11 cooperate to form the shell 30 becomes thicker, and the strength of the shell 30 at the opening becomes higher. For another example, when d / D is smaller, D remains unchanged and d becomes smaller, the protrusion of the second surface 212 from the first surface 211 becomes smaller. When the workpiece is demolded from the punch 20, the punch 20 exerts less force on the workpiece, reducing the risk of tearing during molding. Alternatively, when D is larger and d remains unchanged, the wall thickness of the shell 30 body (corresponding to the second surface, such as the second region 312, see FIG12 ) becomes thicker, and the thickness of the shell 30 opening is less than that of the body, thereby reducing the risk of tearing during demolding.

[0130] Alternatively, d / D may be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc.

[0131] In the above solution, d / D satisfies the above relationship (10%≤d / D≤80%). On the one hand, the larger d is (or the smaller D is), the thicker the opening of the shell 30 formed after the punch 20 cooperates with the through hole 11, and the higher the strength of the opening of the shell 30. When the dimension d of the second surface 212 protruding from the first surface 211 is greater than or equal to 0.1 times the minimum distance D between the second surface 212 and the first inner side surface 111, the thickness of the shell 30 at the corresponding position of the first surface 211 after forming is thicker. The strength here is higher, reducing the risk of the shell 30 cracking near the welding area between the shell 30 and the end cover; on the other hand, d is small (or D is large), the size of the second surface 212 protruding from the first surface 211 is small, and when the workpiece and the punch 20 are demolded, the force exerted by the punch 20 on the workpiece is small. When the size d of the second surface 212 protruding from the first surface 211 is less than or equal to 0.8 times the minimum distance D between the second surface 212 and the first inner side surface 111, the risk of the workpiece being to be processed being torn can be reduced.

[0132] According to some embodiments of the present application, 30%≤d / D≤50%.

[0133] Alternatively, d / D may be, but is not limited to, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, etc.

[0134] In the above scheme, compared with d / D<30%, when d / D≥30%, the thickness of the shell at the position corresponding to the first surface 211 is further increased after molding to improve the strength there; compared with d / D>50%, when d / D≤50%, the risk of cracking of the workpiece to be processed is further reduced.

[0135] Please refer to Figure 6, which is a schematic diagram of the structure of a punch provided in some embodiments of the present application. According to some embodiments of the present application, there are two first outer side surfaces 21, and the two first outer side surfaces 21 are arranged opposite each other in the second direction Y. The punch 20 also has two second outer side surfaces 22 arranged opposite each other in the third direction Z. The third direction Z, the second direction Y, and the first direction X are perpendicular to each other, and the area of ​​the second outer side surfaces 22 is smaller than that of the first outer side surfaces 21.

[0136] The two first outer side surfaces 21 are arranged opposite to each other in the second direction Y, and the two first outer side surfaces 21 are used to form two opposite wall portions of the housing in the second direction Y.

[0137] The two second outer side surfaces 22 are arranged opposite to each other in the third direction Z, and two ends of each second outer side surface 22 are respectively connected to the two first outer side surfaces 21 .

[0138] The area of ​​the second outer side surface 22 is smaller than that of the first outer side surface 21, so that the area of ​​the shell wall corresponding to the second outer side surface 22 is smaller than the area of ​​the shell wall corresponding to the first outer side surface 21. In other words, the shell wall formed by the first outer side surface 21 and the through hole 11 can be the largest surface of the shell. The shell wall formed by the first outer side surface 21 and the through hole 11 can reduce the risk of shell cracking in the area near the weld between the shell and the end cap when the electrode assembly produces large amounts of gas during the battery cell charge and discharge cycle or when the battery cell experiences thermal runaway.

[0139] In the above scheme, the number of the first outer side surfaces 21 is two, which facilitates the molding of the shell; the area of ​​the second outer side surface 22 is smaller than the area of ​​the first outer side surface 21, and the first outer side surface 21 can be used to mold the large surface of the shell, which can reduce the risk of cracking of the shell in the area near the welding position between the shell and the end cover.

[0140] 2, 3, and 6, the punch 20 further includes a lower end surface 26, and two first outer side surfaces 21 and two second outer side surfaces 22 are disposed around the lower end surface 26. When the punch 20 engages with the through hole 11, the lower end surface 26 enters the through hole 11 before the first outer side surfaces 21 and the second outer side surfaces 22.

[0141] During the forming process of the housing 30, the lower end surface 26 of the punch 20 presses the workpiece into the through hole 11 of the die 10. As the workpiece moves within the through hole 11, it is clamped by the hole wall of the through hole 11 and the punch 20. The first outer side surface 21 cooperates with the through hole 11 to form the first wall of the housing, and the second outer side surface 22 cooperates with the through hole 11 to form the second wall of the housing. The lower end surface 26 is used to form the bottom wall of the housing. The first wall and the second wall are the two side walls of the housing, and there are two first walls and two second walls respectively. The two first walls are arranged opposite each other in the second direction Y, and the two second walls are arranged opposite each other in the third direction Z. The two first walls and the two second walls are arranged around the bottom wall. One end of the two first walls and one end of the two second walls are respectively connected to the bottom wall, and the other ends of the two first walls and the other ends of the two second walls form the opening of the housing.

[0142] 6 , according to some embodiments of the present application, the second outer side surface 22 includes a sixth surface 221 and a seventh surface 222 sequentially distributed along the first direction X. Along the third direction Z, the seventh surface 222 protrudes from the sixth surface 221 .

[0143] The sixth surface 221 and the seventh surface 222 are sequentially distributed along the first direction X. After the punch 20 cooperates with the through hole 11 to extrude the workpiece, the sixth surface 221 corresponds to the opening of the structure after the workpiece is extruded.

[0144] Along the third direction Z, the seventh surface 222 protrudes from the sixth surface 221. During the molding process, along the third direction Z, the seventh surface 222 is closer to the wall of the through-hole 11 than the sixth surface 221. During the molding process, the thickness of the structure squeezed by the seventh surface 222 and the wall of the through-hole 11 is relatively thin, while the thickness of the structure squeezed by the sixth surface 221 and the wall of the through-hole 11 is relatively thick.

[0145] In the above scheme, along the third direction Z, the seventh surface 222 protrudes from the sixth surface 221, so that the opening of the wall of the shell 30 corresponding to the second outer side surface 22 is thickened, further reducing the risk of cracking of the shell 30 in the area near the welding position between the shell 30 and the end cover.

[0146] According to some embodiments of the present application, along the third direction Z, the seventh surface 222 may protrude from the sixth surface 221 by a dimension d1, satisfying d1=d.

[0147] According to some embodiments of the present application, the through hole 11 has a second inner side surface. When the punch 20 is engaged with the through hole 11 , the second inner side surface is opposite to the second outer side surface 22 in the third direction Z.

[0148] Along the third direction Z, the minimum distance between the seventh surface 222 and the second inner side surface is D1, which satisfies the following conditions: D1=D, 10%≤d1 / D1≤80%.

[0149] Alternatively, d1 / D1 may be, but is not limited to, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, etc.

[0150] According to some embodiments of the present application, along the first direction X, the second inner side surface includes a tenth surface and an eleventh surface connected in sequence, and when the punch 20 cooperates with the through hole 11, the tenth surface cooperates with the punch 20 before the eleventh surface; along the first direction X, the distance between the tenth surface and the seventh surface 222 in the third direction Z gradually decreases.

[0151] The tenth surface may be located at an opening position where the punch 20 enters the through hole 11 .

[0152] Stamping Process: As the punch 20 engages with the through-hole 11, the seventh surface 222 first engages with the tenth surface. As the punch 20 moves, the seventh surface 222 gradually engages with the eleventh surface. Simultaneously, as the punch 20 moves, the sixth surface 221 gradually engages with the tenth and eleventh surfaces. During the stamping process, the eleventh surface, in conjunction with the seventh and sixth surfaces 222 and 221, forms the second wall 32 of the housing 30 (see FIG. 13 ).

[0153] In the first direction X, the distance between the tenth surface and the seventh surface 222 in the third direction Z gradually decreases from the end of the tenth surface away from the eleventh surface to the end close to the eleventh surface, which is equivalent to that the opening of the through hole 11 near the tenth surface is larger, so as to guide the punch 20 when the punch 20 enters the through hole 11.

[0154] In some embodiments, the eleventh surface is parallel to the first direction X, and the eleventh surface is a plane such that the outer surface of the housing 30 corresponding to the eleventh surface is a plane.

[0155] In the above solution, along the first direction X, the distance between the tenth surface and the seventh surface 222 in the third direction Z gradually decreases, so as to guide the punch 20 when the punch 20 enters the through hole 11 .

[0156] According to some embodiments of the present application, the second inner surface further includes a twelfth surface. Along the first direction X, the tenth surface, the eleventh surface and the twelfth surface are sequentially connected, and the distance between the twelfth surface and the seventh surface 222 in the third direction Z gradually increases.

[0157] The tenth surface, the eleventh surface and the twelfth surface are distributed along the first direction X in sequence.

[0158] The twelfth surface and the tenth surface may be located at both ends of the through hole 11 in the first direction X. For example, the twelfth surface may constitute another opening of the through hole 11. In the first direction X, from the end of the twelfth surface closer to the eleventh surface to the end of the twelfth surface farther from the eleventh surface, the distance between the twelfth surface and the seventh surface 222 in the third direction Z gradually increases. The opening of the through hole 11 near the twelfth surface is larger, so as to facilitate the flow of material when the punch 20 engages with the through hole 11.

[0159] In the above solution, along the first direction X, the distance between the twelfth surface and the seventh surface 222 in the third direction Z gradually increases, so as to facilitate the flow of the material during stamping and release stress.

[0160] According to some embodiments of the present application, the second outer side surface 22 also includes a second transition surface. Along the first direction X, the sixth surface 221, the second transition surface and the seventh surface 222 are distributed in sequence; along the first direction X, the size of the second transition surface protruding from the sixth surface 221 gradually increases.

[0161] In order to distinguish it from the first outer side surface 21 , the aforementioned transition surface 213 may be referred to as a first transition surface.

[0162] The second transition surface is used to connect the sixth surface 221 and the seventh surface 222 to achieve a transition from the sixth surface 221 to the seventh surface 222 .

[0163] In the above solution, the provision of the second transition surface can facilitate the demoulding of the punch 20 and reduce the damage of the punch 20 to the workpiece.

[0164] According to some embodiments of the present application, the second transition surface is a plane, and the angle between the second transition surface and the plane where the seventh surface 222 is located is θ1, satisfying 3°≤θ1=θ≤60°.

[0165] Optionally, θ1 can be but is not limited to 3°, 6°, 9°, 12°, 15°, 18°, 21°, 24°, 27°, 30°, 33°, 36°, 39°, 42°, 45°, 48°, 51°, 54°, 57°, 60°, etc.

[0166] Optionally, 20°≤θ1≤40°.

[0167] In the above scheme, the angle between the second transition surface and the plane where the seventh surface 222 is located satisfies the above range. On the one hand, when θ1≥3°, the processing and molding resistance is small and the demolding resistance is small. On the other hand, when θ1≤60°, the size of the second transition surface in the third direction Z is small, which reduces the space occupied at the corresponding position of the sixth surface 221 after the shell is formed, so that the battery cell can have a higher energy density.

[0168] According to some embodiments of the present application, the second transition surface and the sixth surface 221 transition through a third arc surface, and the second transition surface and the seventh surface 222 transition through a fourth arc surface.

[0169] In the above solution, the second transition surface and the sixth surface 221 transition through the third arc surface, and the second transition surface and the seventh surface 222 transition through the fourth arc surface, which reduces the scratching of the punch 20 on the workpiece during demolding and facilitates demolding.

[0170] According to some embodiments of the present application, the radius of the third arc surface is R3, satisfying 0.05mm≤R3≤0.4mm; and / or the radius of the fourth arc surface is R4, satisfying 0.05mm≤R4≤0.4mm.

[0171] Optionally, R3 may be, but is not limited to, 0.05 mm, 0.07 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.3 mm, 0.33 mm, 0.35 mm, 0.37 mm, 0.4 mm, etc.

[0172] Optionally, R4 may be, but is not limited to, 0.05 mm, 0.07 mm, 0.1 mm, 0.13 mm, 0.15 mm, 0.17 mm, 0.2 mm, 0.23 mm, 0.25 mm, 0.27 mm, 0.3 mm, 0.33 mm, 0.35 mm, 0.37 mm, 0.4 mm, etc.

[0173] In the above scheme, the radius of the third arc surface satisfies the above relationship, and / or the radius of the fourth arc surface satisfies the above relationship. On the one hand, when R3≥0.05mm and / or R4≥0.05mm, the processing difficulty is relatively low. On the other hand, when R3≤0.4mm and / or R4≤0.4mm, the damage of the punch 20 to the workpiece to be processed is reduced, and the damage to the punch 20 during demolding is reduced, so as to improve the life of the punch 20.

[0174] Optionally, 0.08 mm ≤ R3 ≤ 0.12 mm; and / or, 0.08 mm ≤ R4 ≤ 0.12 mm.

[0175] According to some embodiments of the present application, the surface roughness of the third arc surface is Ra3, satisfying 0.01mm≤Ra3≤0.1mm; and / or the surface roughness of the fourth arc surface is Ra4, satisfying 0.01mm≤Ra4≤0.1mm.

[0176] Surface roughness Ra3 and surface roughness Ra4 are both the arithmetic mean deviation of the profile.

[0177] The smaller the surface roughness value, the smoother the surface and the more difficult it is to process and manufacture.

[0178] In the above scheme, the surface roughness of the third arc surface meets the above requirements, and / or the surface roughness of the fourth arc surface meets the above requirements. On the one hand, it reduces the scratching of the punch 20 on the workpiece during demolding, which facilitates demolding. On the other hand, the processing and manufacturing difficulty is low and the processing cost is low.

[0179] Optionally, Ra3 may be, but is not limited to, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, etc.

[0180] Optionally, Ra4 may be, but is not limited to, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, etc.

[0181] Optionally, 0.03mm≤Ra3≤0.07mm; and / or, 0.03mm≤Ra4≤0.07mm.

[0182] Please refer to Figure 7, which is a partial enlarged view of point B in Figure 6. According to some embodiments of the present application, the punch 20 further has a corner surface 23, which connects the adjacent first outer side surface 21 and the second outer side surface 22. The corner surface 23 includes an eighth surface 231 and a ninth surface 232 distributed sequentially along the first direction X. The eighth surface 231 and the ninth surface 232 are both arc surfaces. In the radial direction of the arc surface, the ninth surface 232 protrudes from the eighth surface 231.

[0183] After the punch 20 cooperates with the through hole 11 , the corner surface 23 cooperates with the wall surface of the through hole 11 to squeeze the workpiece, so that in the formed shell, the area near the opening at the corner of the shell is also thickened.

[0184] In some embodiments, the eighth surface 231 connects the first surface 211 and the sixth surface 221, and the ninth surface 232 connects the second surface 212 and the seventh surface 222, so that after the punch 20 cooperates with the through hole 11, the shell formed after the workpiece is extruded is thickened around the circumference of its opening.

[0185] In the above solution, the corners of the punch 20 are thickened so that after the shell is formed, the corners of the shell can be thickened to enhance the strength of the shell and reduce the risk of shell cracking.

[0186] Please refer to Figure 8, which is a schematic diagram of the base and coating of a punch provided in some embodiments of the present application. According to some embodiments of the present application, the punch 20 includes a base 24 and a coating 25 disposed on the surface of the base 24. The base 24 is made of steel, and the coating 25 is made of titanium aluminum chromium nitride, chromium aluminum nitride, or titanium aluminum nitride.

[0187] In the above solution, the base 24 is made of steel and has high strength. The surface of the base 24 is provided with a coating 25 , which can improve the wear resistance of the punch 20 and extend the service life of the punch 20 .

[0188] According to some embodiments of the present application, the punch 20 and the die 10 constitute a set of forming dies 100. During the shell forming process of the battery cell, multiple sets of forming dies 100 need to be set to process the workpiece into a structure of a desired shape.

[0189] Please refer to Figure 6, and further refer to Figures 9 to 13. Figure 9 is a schematic diagram of a punch and a die cooperating to form a shell provided in some embodiments of the present application, Figure 10 is a structural schematic diagram of a shell provided in some embodiments of the present application by the punch and the die cooperating to form, Figure 11 is a cross-sectional view of a shell provided in some embodiments of the present application by the punch and the die cooperating to form, Figure 12 is a partial enlarged view of point C in Figure 11, and Figure 13 is a partial schematic diagram of a second wall provided in some embodiments of the present application. According to some embodiments of the present application, after the workpiece is extruded by the punch 20 and the die 10, the shell 30 is formed, and the shell 30 includes two first walls 31 arranged oppositely along the second direction Y, two second walls 32 arranged oppositely along the third direction Z, and a bottom wall 33, and the bottom wall 33 is arranged opposite to the opening of the shell 30. The first wall 31 includes a first region 311 and a second region 312 sequentially distributed along the first direction X. The first region 311 forms the opening of the housing 30, and the second region 312 is further away from the opening of the housing 30 than the first region 311. The thickness of the first wall 31 is parallel to the second direction Y, and the thickness of the first region 311 is greater than the thickness of the second region 312. The second wall 32 includes a third region 321 and a fourth region 322 sequentially distributed along the first direction X. The third region 321 forms the opening of the housing 30, and the fourth region 322 is further away from the opening of the housing than the third region 321. The thickness of the second wall 32 is parallel to the third direction Z, and the thickness of the third region 321 is greater than the thickness of the fourth region 322.

[0190] During the forming process of the shell 30, the lower end face 26 of the punch 20 presses the workpiece to be processed into the through hole 11 of the die 10. As the workpiece to be processed moves in the through hole 11, the workpiece to be processed is clamped by the hole wall of the through hole 11 and the punch 20. The first outer side face 21 cooperates with the through hole 11 to form the first wall 31 (please refer to Figure 9), and the second outer side face 22 cooperates with the through hole 11 to form the second wall 32. The lower end face 26 is used to form the bottom wall 33.

[0191] For example, the first surface 211 cooperates with the wall of the through hole 11 to form a first region 311, the second surface 212 cooperates with the wall of the through hole 11 to form a second region 312, the sixth surface 221 cooperates with the wall of the through hole 11 to form a third region 321, and the seventh surface 222 cooperates with the wall of the through hole 11 to form a fourth region 322.

[0192] According to some embodiments of the present application, the embodiments of the present application further provide a battery cell manufacturing system, which includes multiple forming molds 100 provided in any of the above embodiments, and the multiple forming molds 100 are used for multiple forming processes of the shell 30.

[0193] In some embodiments, during the molding process of the shell 30 , the shell 30 requires multiple molding dies 100 , in which the punches 20 and the dies 10 have similar structures, and the workpiece is punched multiple times to form the shell 30 of the desired structure.

[0194] For example, in the process of forming a rectangular parallelepiped shell 30, the workpiece to be processed is a sheet-like structure. The workpiece can undergo processes such as large ellipse, medium ellipse, small ellipse, squaring, fine drawing, and shearing to form the shell 30 of the desired structure. Among them, at least the squaring and fine drawing processes use the forming mold 100 provided in the embodiment of the present application.

[0195] According to some embodiments of the present application, referring to Figures 1 to 13, embodiments of the present application provide a forming die 100, which includes a die 10 and a punch 20. The die 10 has a through hole 11, and the punch 20 is used to press a workpiece into the through hole 11, thereby cooperating with the through hole 11 to extrude the workpiece.

[0196] The punch 20 has two first outer sides 21 extending in a first direction X. The two first outer sides 21 are arranged opposite each other along a second direction Y. The punch 20 also has two second outer sides 22, which are arranged opposite each other along a third direction Z. The area of ​​the second outer sides 22 is smaller than that of the first outer side 21. The first outer side 21 includes a first surface 211 and a second surface 212 sequentially arranged along the first direction X. Along the second direction Y, the second surface 212 protrudes from the first surface 211 by a dimension d.

[0197] The through hole 11 has a first inner side surface 111 and a second inner side surface. When the punch 20 is engaged with the through hole 11, the first inner side surface 111 and the first outer side surface 21 are opposite each other in the second direction Y, and the second inner side surface and the second outer side surface 22 are opposite each other in the third direction Z. Along the second direction Y, the minimum distance D between the second surface 212 and the first inner side surface 111 satisfies the condition 10% ≤ d / D ≤ 80%.

[0198] The first outer side surface 21 also includes a transition surface 213. The first surface 211, the transition surface 213, and the second surface 212 are sequentially arranged along the first direction X. The transition surface 213 protrudes from the first surface 211 gradually increasing in size along the first direction X. The transition surface 213 is a plane, and the angle between the transition surface 213 and the plane of the second surface 212 is θ, satisfying 3°≤θ≤60°. The transition surface 213 transitions to the first surface 211 via a first arcuate surface 214, and the transition surface 213 transitions to the second surface 212 via a second arcuate surface 215. The surface roughness of the first arcuate surface 214 is Ra1, satisfying 0.01mm≤Ra1≤0.1mm; and / or the surface roughness of the second arcuate surface 215 is Ra2, satisfying 0.01mm≤Ra2≤0.1mm. The punch 20 includes a base 24 and a coating 25 disposed on the surface of the base 24 . The base 24 is made of steel, and the coating 25 is made of titanium aluminum chromium nitride, chromium aluminum nitride, or titanium aluminum nitride.

[0199] In the molding die 100 of the present embodiment, the second surface 212 protrudes from the first surface 211, thickening the opening of the structure after the workpiece is extruded. This improves the strength of the housing at the opening after molding, reduces the risk of cracking near the weld between the housing and the end cap, and improves the reliability of the battery cell. Furthermore, this arrangement reduces the difficulty of demolding and prolongs the service life of the punch 20.

[0200] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A molding die for molding a battery cell shell, the molding die comprising: a concave die having a through hole; A punch, the punch being used to press the workpiece to be processed into the through hole, so as to cooperate with the through hole to squeeze the workpiece to be processed; In which, the punch has a first outer side surface, the first outer side surface includes a first surface and a second surface distributed in sequence along a first direction, the first direction is the punching direction of the punch, the second surface is configured to enter the through hole before the first surface along the first direction, and along the second direction, the second surface protrudes from the first surface, and the second direction is perpendicular to the first direction.

2. The molding die according to claim 1, wherein: The through hole has a first inner side surface, and when the punch is engaged with the through hole, the first inner side surface is opposite to the first outer side surface in the second direction; Along the first direction, the first inner side surface includes a third surface and a fourth surface connected in sequence, and when the punch is engaged with the through hole, the third surface engages with the punch before the fourth surface; Along the first direction, a distance between the third surface and the second surface in the second direction gradually decreases.

3. The molding die according to claim 2, wherein: The first inner side surface further includes a fifth surface. Along the first direction, the third surface, the fourth surface and the fifth surface are sequentially connected, and a distance between the fifth surface and the second surface in the second direction gradually increases.

4. The molding die according to any one of claims 1 to 3, wherein: The first outer side surface further includes a transition surface, and along the first direction, the first surface, the transition surface and the second surface are distributed in sequence; Along the first direction, the dimension of the transition surface protruding from the first surface gradually increases.

5. The molding die according to claim 4, wherein: The transition surface is a plane, and an angle θ between the transition surface and the plane where the second surface is located satisfies 3°≤θ≤60°.

6. The molding die according to claim 5, wherein: 20°≤θ≤40°.

7. The molding die according to any one of claims 4 to 6, wherein: The transition surface transitions to the first surface via a first arc surface, and the transition surface transitions to the second surface via a second arc surface.

8. The molding die according to claim 7, wherein: The radius of the first arc surface is R1, which satisfies 0.05 mm ≤ R1 ≤ 0.4 mm; and / or The radius of the second arc surface is R2, which satisfies 0.05mm≤R2≤0.4mm.

9. The molding die according to claim 8, wherein: 0.08mm≤R1≤0.12mm; and / or, 0.08mm≤R2≤0.12mm.

10. The molding die according to any one of claims 7 to 9, wherein: The surface roughness of the first arc surface is Ra1, which satisfies 0.01 mm ≤ Ra1 ≤ 0.1 mm; and / or The surface roughness of the second arc surface is Ra2, which satisfies 0.01 mm ≤ Ra2 ≤ 0.1 mm.

11. The molding die according to claim 10, wherein: 0.03mm≤Ra1≤0.07mm; and / or, 0.03mm≤Ra2≤0.07mm.

12. The molding die according to any one of claims 1 to 11, wherein: There are two first outer side surfaces, and the two first outer side surfaces are arranged opposite to each other in the second direction; The punch further has two second outer side surfaces arranged opposite to each other in a third direction, the third direction, the second direction and the first direction are perpendicular to each other, and the area of ​​the second outer side surfaces is smaller than that of the first outer side surfaces.

13. The molding die according to claim 12, wherein: The second outer side surface includes a sixth surface and a seventh surface sequentially distributed along the first direction. Along the third direction, the seventh surface protrudes from the sixth surface.

14. The molding die according to claim 12 or 13, wherein: The punch also has a corner surface, which connects the adjacent first outer side surface and the second outer side surface. The corner surface includes an eighth surface and a ninth surface distributed in sequence along the first direction. The eighth surface and the ninth surface are both arc surfaces. Along the radial direction of the arc surface, the ninth surface protrudes from the eighth surface.

15. The molding die according to any one of claims 1 to 14, wherein: The through hole has a first inner side surface, and when the punch is engaged with the through hole, the first inner side surface is opposite to the first outer side surface in the second direction; The dimension d of the second surface protruding from the first surface is greater than or equal to 0.1 times the minimum distance D between the second surface and the first inner side surface, and the dimension d of the second surface protruding from the first surface is less than or equal to 0.8 times the minimum distance D between the second surface and the first inner side surface.

16. The molding die according to claim 15, wherein: The dimension d of the second surface protruding from the first surface is greater than or equal to 0.3 times the minimum distance D between the second surface and the first inner side surface, and the dimension d of the second surface protruding from the first surface is less than or equal to 0.5 times the minimum distance D between the second surface and the first inner side surface.

17. The molding die according to any one of claims 1 to 16, wherein: The punch includes a base and a coating provided on the surface of the base. The base is made of steel, and the coating is made of titanium aluminum chromium nitride, chromium aluminum nitride, or titanium aluminum nitride.

18. A battery cell manufacturing system, comprising a plurality of molding dies according to any one of claims 1 to 17, wherein the plurality of molding dies are used for a plurality of molding processes of the housing.

Images