Battery

Abstract

The utility model provides a battery, comprising: a cover plate assembly comprising a cover plate body and a pole in insulated connection with the cover plate body; the naked battery cell is located on one side of the cover plate body in the thickness direction, the naked battery cell comprises a battery cell body and a tab, and the tab comprises a fixing part connected with the pole; the protection sheet is welded on the surface, far away from the pole, of the fixing part so as to form a welding mark on a first plate surface, far away from the fixing part, of the protection sheet; a protruding protrusion structure is formed on the first plate face and located on at least one side of the welding mark in the circumferential direction. According to the battery provided by the invention, the first plate surface of the protection sheet is used as the surface of the welding area instead of the tab, so that the risk of cracking of the tab is reduced, and the welding yield is improved. Meanwhile, the convex structure on the first plate surface can play a role in blocking foreign matters, so that the mechanical damage of the foreign matters to welding marks is reduced, and reliable electrical connection can be formed between the tab and the post terminal.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a battery. Background Art

[0002] In the prior art, a battery includes a housing with an opening at the top, a bare cell mounted within the housing, and a cover assembly that covers the housing opening. To electrically connect the bare cell to the cover assembly, the tabs of the bare cell are typically welded to the posts of the cover assembly.

[0003] However, during the subsequent assembly of the bare cell and the cover assembly after welding, the portion of the tab near the weld mark may tear, thereby causing failure of the electrical connection between the bare cell and the cover assembly. Utility Model Content

[0004] In view of this, the purpose of the present application is to provide a battery to at least partially solve the problem of electrical connection failure between the bare cell and the cover assembly caused by tearing of the tab welded to the pole.

[0005] Based on the above-mentioned purpose, the present application provides a battery, including: a cover plate assembly, including a cover plate body, and a pole insulated and connected to the cover plate body; a bare cell, located on one side of the cover plate body in the thickness direction, the bare cell including a cell body and a pole tab, the pole tab including a fixing portion connected to the pole; a protective sheet, welded to the surface of the fixing portion away from the pole to form a weld mark on the first plate surface of the protective sheet away from the fixing portion; the first plate surface is formed with a protruding protrusion structure, and the protrusion structure is located on at least one side of the circumference of the weld mark.

[0006] Optionally, at least one side edge of the protection sheet is bent in a direction away from the fixing portion to form a bent portion serving as the protruding structure.

[0007] Optionally, the bent portion includes a first bent sub-portion, and along the length direction of the cover plate body, the first bent sub-portion is located on at least one side of the weld mark.

[0008] Optionally, the electrode ear includes a fixing portion, a bending portion and a connecting portion connected in sequence along a first direction; the connecting portion is connected to the battery cell body, and the bending portion is bent along a second direction; the first direction is the thickness direction of the cover body, and the second direction is the width direction of the cover body; the protective sheet is spaced apart from the battery cell body along the first direction; the bent portion includes a second bent portion, and along the second direction, the second bent portion is close to the bent portion to separate the bent portion from the battery cell body.

[0009] Optionally, along the second direction, the distance between the edge of the protective sheet close to the bending portion and the adjacent weld edge is a, and the distance between the edge of the protective sheet away from the bending portion and the adjacent weld edge is b, and a is greater than b.

[0010] Optionally, the dimension of the protection sheet along the second direction is defined as the width c of the protection sheet, and a is greater than or equal to half of c.

[0011] Optionally, the extension length of the tab is d, and c is one third to two thirds of d.

[0012] Optionally, the angle f formed between the first plate surface of the bent portion and the first plate surface where the weld mark is located is an obtuse angle.

[0013] Optionally, one end of the pole close to the bare cell is electrically connected to a pole bottom plate, and the fixing portion and the protective sheet are laser welded to the pole bottom plate.

[0014] Optionally, one end of the pole close to the bare cell is electrically connected to a pole base plate, a surface of the pole base plate close to the bare cell is connected to a transition piece, and the fixing portion and the protective piece are ultrasonically welded to the transition piece.

[0015] As can be seen from the above, in the battery provided by the present application, when welding the tab of the bare cell to the post of the cover plate assembly, the first plate surface of the protective sheet can replace the tab as the surface of the welding area, which can at least to a certain extent reduce the heat transferred to the tab surface, help reduce the risk of tab cracking, and improve the welding quality rate. At the same time, because the first plate surface is also provided with a raised structure, the raised structure can block external foreign matter when it moves toward the weld mark, thereby reducing the mechanical damage caused by foreign matter to the weld mark, helping to improve the welding strength between the fixed portion of the tab and the post, and ensuring that a more reliable electrical connection can be formed between the tab and the post. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A partial schematic diagram of a first battery according to an embodiment of the present application;

[0018] Figure 2 A partial schematic diagram of a second battery according to an embodiment of the present application;

[0019] Figure 3 A partial schematic diagram of a third battery according to an embodiment of the present application;

[0020] Figure 4 for Figure 3 An enlarged schematic diagram of part A in FIG;

[0021] Figure 5 for Figure 4 Partial diagram of the B view;

[0022] Figure 6 This is a schematic diagram of two bare cells of a third battery according to an embodiment of the present application in a flattened state before being joined together;

[0023] Figure 7 for Figure 6 A magnified schematic diagram of part C;

[0024] Figure 8 A welding tool for welding the protective sheet of the battery of the embodiment of the present application;

[0025] Figure 9 It is a cross-sectional schematic diagram of the welding tool;

[0026] Figure 10 A partial schematic diagram of a fourth battery according to an embodiment of the present application;

[0027] Figure 11 This is a schematic diagram of two bare cells of the fourth battery of an embodiment of the present application in a flattened state.

[0028] Description of reference numerals:

[0029] 100, cover plate assembly; 110, cover plate body; 120, pole; 130, pole base plate; 140, adapter;

[0030] 200, bare cell; 210, cell body; 220, tab; 221, fixing portion; 222, bending portion; 223, connecting portion;

[0031] 300, protective sheet; 310, flat portion; 320, curved portion; 321, first curved portion; 322, second curved portion; 330, first panel;

[0032] 400, welding stamp;

[0033] 500, tooling body; 510, welding through-hole; 520, protective sheet support platform. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0035] It should be noted that the relative arrangement of the components, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise.

[0036] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0038] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] In some embodiments, as Figure 1 , Figure 1 The first battery is shown in a partial schematic diagram, wherein the cover assembly 100 includes a cover body 110 and a pole 120 passing through the cover body 110, one end of the pole 120 is located outside the cover body 110 (eg Figure 1 The other end of the pole 120 is located on the inner side of the cover body 110 (such as Figure 1 A pole base plate 130 is provided at one end of the pole 120 located inside the cover body 110. The pole base plate 130 is welded (e.g., by laser welding) to a transfer plate 140. The tab 220 of the bare cell 200 is welded to the transfer plate 140 (e.g., by ultrasonic welding).

[0040] In this embodiment, the weld mark 400 formed when the tab 220 is welded to the adapter 140 is located on the surface of the tab 220. The tab 220 is constructed by laminating multiple layers of metal foil (e.g., copper foil). If the weld mark 400 is directly located on the tab 220, if a high weld strength is ensured between the tab 220 and the adapter 140, the outermost layer of metal foil may crack. If the outermost layer of metal foil is ensured to be intact, the weld strength between the tab 220 and the adapter 140 may fall below the process requirements.

[0041] In some embodiments, as Figure 2 , Figure 2 A partial schematic diagram of the second type of battery is shown, in which the tab 220 of the bare cell 200 can also be directly welded to the pole bottom plate 130. Similarly, the weld mark 400 formed when the tab 220 and the pole bottom plate 130 are welded is located on the surface of the tab 220.

[0042] The applicant's research has found that one reason the metal foil of the tab 220 cracks after welding is that the surface temperature of the welding area is high during welding, and the thickness of the metal foil of the tab 220 is relatively small. The metal foil cracks under the influence of high temperature. If the tab 220 does not serve as the surface of the welding area, the cracking problem can be alleviated.

[0043] In addition, the applicant also found that the reason for the low welding strength is that the metal foil of the tab 220 may crack, and the other reason is that during the assembly process of the bare cell 200 and the cover assembly 100, the weld mark 400 is exposed on the plane. Figure 1 and Figure 2 , which may be bumped by other structural parts or assembly tools (such as the connecting portion 223 of the tab 220, hereinafter referred to as foreign matter), causing the weld mark 400 to be damaged.

[0044] In order to solve the above problems, the present invention provides a battery. Figure 3 A partial schematic diagram of the third type of battery is shown. Figure 4 Shown Figure 3 Schematic diagram of the enlarged portion A.

[0045] like Figure 3 and Figure 4 The battery includes: a cover assembly 100, including a cover body 110, and a pole 120 insulated and connected to the cover body 110; a bare cell 200, located in the thickness direction of the cover body 110 (such as Figure 3On one side of the battery cell 200 (in the Z direction), the bare battery cell 200 includes a battery cell body 210 and a tab 220, and the tab 220 includes a fixing portion 221 connected to the pole 120; the protective sheet 300 is welded to the surface of the fixing portion 221 away from the pole 120 to form a weld mark 400 on the first plate surface 330 of the protective sheet 300 away from the fixing portion 221; the first plate surface 330 is formed with a protruding protrusion structure, and the protrusion structure is located on at least one side of the circumference of the weld mark 400.

[0046] For example, the pole 120 and the cover body 110 may be insulated and connected by an insulating ring sleeved on the outside of the pole 120 .

[0047] For example, the protruding structure may be connected to the first plate surface 330 of the protective sheet 300 by welding, bonding, or integral molding.

[0048] For example, the raised structure may extend along the edge of the weld mark 400 .

[0049] Exemplarily, the height of the protruding structure protruding from the first plate surface 330 is greater than the height of the welding stamp 400 protruding from the first plate surface 330 .

[0050] In this embodiment, the protective sheet 300 and the fixing portion 221 of the tab 220 can be fixed to the electrode 120 through a welding process to achieve an electrical connection between the tab 220 and the electrode 120. The weld mark 400 is formed on the first plate surface 330 of the protective sheet 300. That is, the first plate surface 330 serves as the surface of the welding area during welding, and has a certain covering and protective effect on the metal foil of the tab 220, which helps to reduce the heat transferred to the tab 220 during welding.

[0051] At the same time, if an external foreign object approaches the weld mark 400 on the first plate surface 330, when the foreign object contacts the raised structure formed on the first plate surface 330, the raised structure will block the foreign object and prevent the foreign object from causing damage to the weld mark 400.

[0052] In the battery provided in the embodiment of the present application, when welding the tab 220 of the bare cell 200 to the post 120 of the cover plate assembly 100, the first plate surface 330 of the protective sheet 300 can replace the tab 220 as the surface of the welding area, which can at least to a certain extent reduce the heat transferred to the surface of the tab 220, helping to reduce the risk of cracking in the tab 220 and improving the welding quality. At the same time, because a raised structure is also provided on the first plate surface 330, the raised structure can block external foreign matter when it moves toward the weld mark 400, thereby reducing the mechanical damage caused by the foreign matter to the weld mark 400, helping to improve the welding strength between the fixing portion 221 of the tab 220 and the post 120, and ensuring that a more reliable electrical connection can be formed between the tab 220 and the post 120.

[0053] like Figure 4 In some embodiments, at least one side edge of the protective sheet 300 is bent in a direction away from the fixing portion 221 to form a bent portion 320 as a protruding structure.

[0054] For example, the protection sheet 300 may be an integrally formed structural member formed by a sheet metal stamping process.

[0055] Exemplarily, the middle portion of the protective sheet 300 is a flat portion 310, and the weld mark 400 is formed on the first plate surface 330 of the flat portion 310. The thickness of the flat portion 310 can be 0.05 mm to 0.5 mm, for example, 0.05 mm, 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0056] Exemplarily, the bent portion 320 is curved.

[0057] The portion of the protective sheet 300 close to the edge is bent to form a curved portion 320 as a raised structure, that is, the flat portion 310 of the protective sheet 300 is integrally formed and connected to the curved portion 320. On the one hand, this can reduce the overall difficulty and cost of preparing the protective sheet 300, which is beneficial to the mass production of batteries; on the other hand, the integrally formed protective sheet 300 can also make the connection between the flat portion 310 and the curved portion 320 more reliable, thereby preventing the curved portion 320 from being separated from the flat portion 310 on which the weld mark 400 is formed when impacted by foreign objects, thereby ensuring that the curved portion 320 can continuously and reliably protect the weld mark 400.

[0058] like Figure 5 , Figure 5 Shown Figure 4 In the partial schematic diagram of the view in the direction of B, in some embodiments, the curved portion 320 includes a first curved portion 321, which is arranged along the length direction of the cover body 110 (eg Figure 5 In the X direction), the first curved portion 321 is located on at least one side of the welding mark 400.

[0059] For example, along the length direction of the cover body 110, the first curved portions 321 are located on opposite sides of the weld mark 400. The two first curved portions 321 and the flat portion 310 form a U-shaped structure, and the weld mark 400 is located on the inner surface of the U-shaped structure. The first curved portions 321 on both sides can better protect the weld mark 400.

[0060] Typically, the size of the weld mark 400 along the length direction of the cover plate body 110 is larger than the size along the width direction of the cover plate body 110 (e.g., Figure 4In this embodiment, when the first curved portion 321 is positioned on one side of the weld stamp 400 along the length of the cover plate body 110, the first curved portion 321 extends a short distance along the edge of the weld stamp 400 to extend beyond both ends of the edge of the weld stamp 400, thereby providing relatively comprehensive protection for the weld stamp 400. While ensuring relatively reliable protection for the weld stamp 400 by the first curved portion 321, the material cost of forming the first curved portion 321 can also be reduced, facilitating mass production.

[0061] When the battery includes two bare cells 200, after the tabs 220 of the bare cells 200 are welded to the poles 120 of the cover assembly 100, the two bare cells 200 are bundled (or called core-binding). At this time, the tabs 220 are bent into a C-shaped structure. Figure 1 In some embodiments, the tab 220 is arranged along a first direction (eg Figure 1 The Z direction in the figure) includes a fixing portion 221, a bending portion 222 and a connecting portion 223 connected in sequence; the connecting portion 223 is connected to the battery cell body 210, and the bending portion 222 is along the second direction (such as Figure 1 the first direction is the thickness direction of the cover body 110, and the second direction (Y) is the width direction of the cover body 110.

[0062] When the tab 220 is subjected to a downward force (the force may be applied to the tab 220 by the cover assembly 100), the bent portion 222 of the tab 220 is likely to bend downward. Since the distance between the bent portion 222 and the top of the battery cell body 210 is small, when the bent portion 222 bends downward, it is likely to contact the electrode in the battery cell body 210, causing an internal short circuit in the battery or a potential safety risk.

[0063] In order to avoid the above situation, Figure 4 and Figure 5 In some embodiments, the protective sheet 300 is spaced apart from the battery cell body 210 along the first direction; the bent portion 320 includes a second bent portion 322 (located on the side of the weld mark 400 close to the bent portion 222), and along the second direction, the second bent portion 322 is close to the bent portion 222 to separate the bent portion 222 from the battery cell body 210.

[0064] Illustratively, the second curved portion 322 and the bent portion 222 may or may not contact each other.

[0065] Since the protective sheet 300 is spaced apart from the battery cell body 210, when the tab 220 is subjected to a downward force, the protective sheet 300 can support the bent portion 222 of the tab 220, effectively preventing the bent portion 222 from moving toward the top of the battery cell body 210, avoiding contact between the tab 220 and the electrode in the battery cell body 210, and reducing the risk of internal short circuit in the battery.

[0066] At the same time, a second bent portion 322 that bends downward is provided at a position of the protective sheet 300 near the bending portion 222. Then, when the protective sheet 300 supports the pole lug 220, what contacts the bending portion 222 is the side surface of the second bent portion 322, rather than the sharp edge of the protective sheet 300. This can prevent the edge of the protective sheet 300 from scratching the metal foil of the pole lug 220, thereby ensuring the reliability of the connection between the pole lug 220 and the pole 120.

[0067] At the same time, the second curved portion 322 can also block foreign objects approaching the weld mark 400, thereby protecting the weld mark 400.

[0068] like Figure 4 In some embodiments, along the first direction, a height difference e between the end of the bent portion 320 and the first board surface 330 where the weld stamp 400 is located is greater than 0 and less than or equal to 2 cm.

[0069] The raised height of the warped portion 320 is limited to the range of 0<e≤2mm, that is, the warped portion 320 can block foreign objects, thereby protecting the weld mark 400, and can also avoid the warped portion 320 located between the fixed portion 221 and the connecting portion 223 from squeezing the connecting portion 223 downward due to the small distance between the fixed portion 221 and the connecting portion 223 of the tab 220 along the first direction, thereby further reducing the risk of the tab 220 contacting the electrode of the battery cell body 210.

[0070] like Figure 4 In some embodiments, the angle f between the first plate surface 330 of the bent portion 320 and the first plate surface 330 where the weld mark 400 is located (ie, the first plate surface 330 of the flat portion 310 ) is an obtuse angle.

[0071] If the angle f is an acute angle, the warped portion 320 will block the first plate surface 330 where the weld mark 400 is located, hindering the welding of the protective sheet 300 to the tab 220 and the terminal post 120. Therefore, in this embodiment, the angle f is designed to be an obtuse angle. While ensuring that the warped portion 320 can protect the weld mark 400, it can also prevent the warped portion 320 from blocking the first plate surface 330 where the weld mark 400 is to be formed.

[0072] Figure 6 A schematic diagram showing two bare cells 200 of a third type of battery in a flattened state before being joined together is shown. Figure 7 Shown Figure 6 Enlarged schematic diagram of part C.

[0073] like Figure 6 and Figure 7 In some embodiments, along the second direction, the distance between the edge of the protective sheet 300 close to the bending portion 222 and the edge of the adjacent weld mark 400 is a, and the distance between the edge of the protective sheet 300 away from the bending portion 222 and the edge of the adjacent weld mark 400 is b, and a is greater than b.

[0074] Exemplarily, the distance b meets the welding process requirements.

[0075] In combination with the foregoing, in this embodiment, the protective sheet 300 is eccentrically arranged relative to the weld mark 400, that is, the protective sheet 300 is closer to the bent portion 222 of the tab 220, so that the protective sheet 300 can provide a more reliable support for the bent portion 222 of the tab 220, so as to prevent the bent portion 222 from moving downward and contacting the pole piece of the battery body 210, thereby preventing the battery from having an internal short circuit.

[0076] like Figure 6 and Figure 7 In some embodiments, the dimension of the protection sheet 300 along the second direction is defined as the width c of the protection sheet 300 , and a is greater than or equal to half of c.

[0077] In this embodiment, the eccentric distance of the protective sheet 300 relative to the weld mark 400 can be determined based on the width of the protective sheet 300. The reason for limiting the eccentric distance is to enable the protective sheet 300 to confine more of the bent portion 222 above the protective sheet 300, further reducing the risk of contact between the tab 220 and the electrode of the cell body 210. This prevents the portion of the bent portion 222 that is away from the protective sheet 300 from moving downward due to the protective sheet 300 not extending into the bend position of the bent portion 222 being unable to be supported by the protective sheet 300.

[0078] like Figure 6 and Figure 7 In some embodiments, the extension length of the tab 220 is d, and c is one-third to two-thirds of d.

[0079] Exemplarily, the dimension of the protective sheet 300 along the length direction of the cover body 110 is defined as the length of the protective sheet 300, and the length of the protective sheet 300 is greater than the length of the weld mark 400. For example, the length of the protective sheet 300 can be 3 mm, 4 mm or 5 mm greater than the length of the weld mark 400.

[0080] In this embodiment, the width of the protective sheet 300 is limited in order to ensure that the protective sheet 300 can provide a relatively comprehensive support to the bent portion 222 of the tab 220 , while also avoiding interference with the bent portion 222 due to the protective sheet 300 being too long, thereby causing the metal foil of the tab 220 to break.

[0081] like Figure 3 and Figure 6 In some embodiments, one end of the pole 120 close to the bare cell 200 is electrically connected to the pole base plate 130, the surface of the pole base plate 130 close to the bare cell 200 is connected to the adapter plate 140, and the fixing portion 221 and the protective sheet 300 are ultrasonically welded to the adapter plate 140.

[0082] When the fixing portion 221 of the tab 220 and the pole 120 need to be electrically connected via the adapter 140 , a portion of the adapter 140 is welded to the pole bottom plate 130 , while another portion is welded to the fixing portion 221 .

[0083] Exemplarily, the pole base plate 130 is connected to one side surface of the adapter plate 140, the fixing portion 221 is connected to the other side surface opposite to the adapter plate 140, and the protective sheet 300 is connected to the surface of the fixing portion 221 away from the adapter plate 140 to support the pole ear 220 and protect the weld mark 400 formed on the protective sheet 300.

[0084] Figure 8 The welding tool for welding the protective sheet 300 is shown. Figure 9 A cutaway diagram of the welding tooling is shown.

[0085] like Figure 8 and Figure 9 The welding tool includes a tool body 500, and the tool body 500 is formed along the thickness direction (such as Figure 8 A through-hole 510 is provided (in the Z direction in FIG. 1 ). The radial cross-sectional shape of the through-hole 510 matches the shape of the protective sheet 300. A protective sheet support 520 is provided on the wall of the through-hole 510. The position of the protective sheet support 520 corresponds to the position of the curved portion 320 of the protective sheet 300.

[0086] Illustratively, the thickness of the protection sheet support platform 520 may be 0.5 mm to 2 mm, for example, 0.5 mm, 1 mm, 1.5 mm or 2 mm.

[0087] Before welding, the adapter sheet 140 to be welded can be placed on the ultrasonic welding seat, and then the fixing portion 221 of the tab 220 to be welded can be placed at a preset position on the surface of the adapter sheet 140. Then, the welder can be placed above the fixing portion 221, and the welding through-hole 510 can be moved to the position where the protective sheet 300 needs to be welded. At this time, the protective sheet support platform 520 is close to or in contact with the surface of the tab 220. Afterwards, the protective sheet 300 to be welded (the protective sheet 300 as a whole can be a flat plate-shaped structure at this time) is placed into the welding through-hole 510, and a portion of the protective sheet 300 close to the edge (i.e., the area where the warped portion 320 needs to be formed) is supported by the protective sheet support platform 520.

[0088] During welding, the ultrasonic welding head extends into the welding through hole 510 and presses the middle part of the protective sheet 300 downward until the middle part of the protective sheet 300 (i.e., the part not supported by the protective sheet support platform 520) is attached to the surface of the fixing part 221 and welded.

[0089] After welding is completed, the middle portion of the protection sheet 300 is in contact with the surface of the fixing portion 221 to form a flat portion 310 of the protection sheet 300 ; and the portion supported by the protection sheet support platform 520 is bent to form a curved portion 320 of the protection sheet 300 .

[0090] Finally, the adapter plate 140 welded with the tab 220 and the protection sheet 300 is welded to the pole bottom plate 130 .

[0091] Figure 10 A partial schematic diagram of the fourth type of battery is shown. Figure 11 A schematic diagram of two bare cells 200 of a fourth type of battery in a flattened state is shown.

[0092] like Figure 10 and Figure 11 In some embodiments, one end of the pole 120 close to the bare cell 200 is electrically connected to the pole bottom plate 130 , and the fixing portion 221 and the protective sheet 300 are laser welded to the pole bottom plate 130 .

[0093] When the tab 220 is directly electrically connected to the terminal post 120, one side of the fixing portion 221 of the tab 220 is in contact with the terminal post base plate 130, while the other side is in contact with the protective sheet 300. Similarly, the protective sheet 300 connected to the fixing portion 221 can support the tab 220 and protect the weld mark 400 formed on the protective sheet 300.

[0094] Before welding, the pole 120 can be fixed first, and the pole base plate 130 can be placed upward. After that, the fixing portion 221 of the pole tab 220 to be welded is placed at a preset position on the surface of the pole base plate 130. Then, the welder is placed above the fixing portion 221, and the welding through-hole 510 is moved to the position where the protective sheet 300 needs to be welded. At this time, the protective sheet support platform 520 is close to or in contact with the surface of the pole tab 220. After that, the protective sheet 300 to be welded (the protective sheet 300 as a whole can be a flat plate structure at this time) is placed into the welding through-hole 510, and the protective sheet 300 is supported by the protective sheet support platform 520. Finally, it is necessary to place a pressure block into the welding through hole 510. The pressure block can be a frame structure. The pressure block presses the protective sheet 300 downward until the middle of the protective sheet 300 (that is, the part not supported by the protective sheet support platform 520) is in contact with the surface of the fixing part 221. A through hole is provided in the middle of the pressure block to expose the area on the protective sheet 300 where the weld mark 400 needs to be formed.

[0095] During welding, the laser passes through the through hole on the pressing block and acts on the protection sheet 300 to complete the welding between the protection sheet 300, the pole tab 220 and the pole bottom plate 130.

[0096] After welding is completed, the middle portion of the protection sheet 300 is in contact with the surface of the fixing portion 221 to form a flat portion 310 of the protection sheet 300 ; and the portion supported by the protection sheet support platform 520 is bent to form a curved portion 320 of the protection sheet 300 .

[0097] It should be noted that the batteries in the above embodiments may be lithium-ion batteries, sodium-ion batteries, or electrochemical devices with the same structure and principle.

[0098] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0099] The various embodiments in this application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0100] The description of this application is provided for purposes of illustration and description and is not intended to be exhaustive or to limit the application to the disclosed form. Many modifications and variations will be apparent to those skilled in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the application and to enable those skilled in the art to understand the application and design various embodiments with various modifications suitable for specific applications.

[0101] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application is limited to these examples. In line with the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0102] While the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0103] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A battery, characterized in that: include: The cover plate assembly comprises a cover plate body and a pole insulated from the cover plate body; A bare cell located on one side of the cover body in the thickness direction, the bare cell comprising a cell body and a tab, the tab comprising a fixing portion connected to the pole; A protective sheet is welded to the surface of the fixing portion away from the pole to form a weld mark on the first plate surface of the protective sheet away from the fixing portion; the first plate surface is formed with a protruding convex structure, and the convex structure is located on at least one side of the weld mark in a circumferential direction.

2. The battery according to claim 1, characterized in that At least one side edge of the protection sheet is bent in a direction away from the fixing portion to form a bent portion serving as the protruding structure.

3. The battery according to claim 2, characterized in that The bent portion includes a first bent portion, and along the length direction of the cover body, the first bent portion is located on at least one side of the weld mark.

4. The battery according to claim 2, characterized in that The tab includes a fixing portion, a bending portion, and a connecting portion connected in sequence along a first direction; the connecting portion is connected to the battery cell body, and the bending portion is bent along a second direction; the first direction is the thickness direction of the cover plate body, and the second direction is the width direction of the cover plate body; The protective sheet is spaced apart from the battery cell body along the first direction; the bent portion includes a second bent sub-portion, and along the second direction, the second bent sub-portion is close to the bent portion to separate the bent portion from the battery cell body.

5. The battery according to claim 4, characterized in that Along the second direction, the distance between the edge of the protective sheet close to the bending portion and the adjacent weld edge is a, and the distance between the edge of the protective sheet away from the bending portion and the adjacent weld edge is b, and a is greater than b.

6. The battery according to claim 5, characterized in that The dimension of the protection sheet along the second direction is defined as the width c of the protection sheet, and a is greater than or equal to half of c.

7. The battery according to claim 6, characterized in that The extension length of the tab is d, and c is one third to two thirds of d.

8. The battery according to claim 2, characterized in that An angle f formed between the first plate surface of the bent portion and the first plate surface where the weld mark is located is an obtuse angle.

9. The battery according to claim 1, characterized in that One end of the pole close to the bare cell is electrically connected to a pole bottom plate, and the fixing portion and the protective sheet are laser welded to the pole bottom plate.

10. The battery according to claim 1, characterized in that One end of the pole close to the bare cell is electrically connected to a pole bottom plate, a surface of the pole bottom plate close to the bare cell is connected to a transition piece, and the fixing portion and the protective piece are ultrasonically welded to the transition piece.

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