Battery cell, battery module, battery pack and electric equipment

Abstract

The invention provides a battery cell, a battery module, a battery pack and electric equipment, and relates to the technical field of batteries. The battery cell comprises a shell, a roll core, a first tab, a second tab, a third tab, and a first output electrode and a second output electrode which are arranged on the shell; the roll core is arranged in the shell and comprises a first pole piece and a second pole piece which are opposite in polarity, and a roll core main body is provided with a first end and a second end; the first tab and the second tab are arranged at the first end and are respectively connected to the first pole piece and the second pole piece; and the third tab is arranged at the second end and is connected to the first pole piece or the second pole piece. According to the application, the first tab and the second tab are arranged at one end of the roll core to respectively collect the current of the positive electrode and the negative electrode, and the third tab is arranged at the other end of the roll core as the current of the positive electrode or the negative electrode, so that the current collecting area of the pole piece connected with the third tab can be increased, and the conduction paths of electrons are increased; therefore, the current collecting capacity of the pole piece can be improved. Therefore, the current collecting capacity of the battery cell can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery cell, battery module, battery pack, and electrical equipment. Background Technology

[0002] In related technologies, a battery cell includes a casing and a wound core disposed within the casing. The wound core includes a positive electrode sheet, a separator, and a negative electrode sheet that are stacked and wound sequentially. Typically, the positive and negative electrodes of the battery cell can be output from the same side or from their respective ends. In the structure where the positive and negative electrodes are output from the same side, the casing of the battery cell is generally used as the output electrode of the negative electrode. Simultaneously, a mounting position for installing a terminal post is insulated and isolated on the top cover of the casing using a sealing element. A terminal post is installed in this mounting position as the output electrode of the positive electrode. A positive electrode tab and a negative electrode tab are respectively provided at the end of the wound core near the top cover. The negative electrode tab is connected to the top cover, and the positive electrode tab is connected to the terminal post, thereby leading out the positive and negative electrodes of the battery cell from the same end of the battery cell. In a structure where positive and negative electrodes are output from both ends of the battery cell, the positive and negative electrodes are located at both ends of the winding core, respectively. The positive electrode is connected to the positive terminal, and the negative electrode is connected to the negative terminal or the outer shell of the battery cell, thereby leading out the positive and negative electrodes of the battery cell from both ends of the battery cell.

[0003] In the above scheme, although the current collection capacity of the battery cell basically meets the application requirements of the battery cell, there is still room for improvement in the current collection capacity of the battery cell. Summary of the Invention

[0004] The embodiments of this application provide a battery cell, a battery module, a battery pack, and an electrical device that can improve the current collection capability of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, which includes a housing, a core, a first tab, a second tab, a third tab, a first output electrode, and a second output electrode. The housing has a receiving cavity. The core is disposed within the receiving cavity and includes a first electrode, a second electrode, and a diaphragm disposed between the first and second electrodes. The first and second electrodes have opposite polarities. Along the axial direction of the core, the core body has a first end and a second end. The first tab is disposed at the first end and connected to the first electrode. The second tab is disposed at the first end and connected to the second electrode. The third tab is disposed at the second end and connected to either the first or the second electrode. The first and second output electrodes are disposed in the housing, with the first output electrode electrically connected to the first tab and the second output electrode electrically connected to the second tab.

[0006] In one embodiment, multiple layers of third tabs are bent and stacked to form a third tab region, which extends circumferentially along the core body in a closed or open ring shape.

[0007] In one embodiment, along the radial direction of the core, from the center of the core body outward, a first central loop area and a third pole loop area are sequentially provided at the second end.

[0008] In one embodiment, the inner diameter of the third tab region is C, and the outer diameter of the core body is A, satisfying: 3%A≤C≤30%A.

[0009] In one embodiment, along the radial direction of the core, from the center of the core body outward, a third pole lug area and a first peripheral hollow lug area are sequentially provided at the second end.

[0010] In one embodiment, the outer diameter of the third tab region is D, and the outer diameter of the core body is A, satisfying: 65%A≤D≤80%A.

[0011] In one embodiment, the third electrode tab is connected to the first electrode plate, with a plane perpendicular to the axis of the core body as the projection plane and the axis of the core body as the projection direction. In the projection plane, the projection of the first electrode tab before bending and the projection of the third electrode tab before bending at least partially overlap. Alternatively, the third electrode tab is connected to the second electrode plate, with a plane perpendicular to the axis of the core body as the projection plane and the axis of the core body as the projection direction. In the projection plane, the projection of the second electrode tab before bending and the projection of the third electrode tab before bending at least partially overlap.

[0012] In one embodiment, the core further includes a fourth tab, which is disposed at the second end of the core body. One of the third tab and the fourth tab is connected to the first electrode plate, and the other is connected to the second electrode plate.

[0013] In one embodiment, multiple layers of third tabs are bent and stacked to form a third tab region, and multiple layers of fourth tabs are bent and stacked to form a fourth tab region. Along the radial direction of the core body, from the center of the core body outward, the second end is sequentially provided with a fourth tab region, a first middle ring hollow tab region, and a third tab region. The fourth tab region and the third tab region extend along the circumference of the core body to form a closed or open ring.

[0014] In one embodiment, multiple layers of third pole ears are bent and stacked to form a third pole ear region, and multiple layers of fourth pole ears are bent and stacked to form a fourth pole ear region. Along the radial direction of the core body, from the center of the core body outward, a third central hollow ear region, a fourth pole ear region, and a third pole ear region are sequentially provided at the second end. The fourth pole ear region and the third pole ear region extend along the circumference of the core body to form a closed or open ring.

[0015] In one embodiment, the inner diameter of the fourth tab region is J, and the outer diameter of the core body is A, satisfying: 3%A≤J≤22%A.

[0016] In one embodiment, multiple layers of third pole ears are bent and stacked to form a third pole ear region, and multiple layers of fourth pole ears are bent and stacked to form a fourth pole ear region. Along the radial direction of the core body, from the center of the core body outward, a fourth pole ear region, a third pole ear region, and a third peripheral hollow ear region are sequentially provided at the second end. The fourth pole ear region and the third pole ear region extend along the circumference of the core body to form a closed or open ring.

[0017] In one embodiment, the outer diameter of the third tab region is D, and the outer diameter of the core body is A, satisfying: 85%A≤D<100%A.

[0018] In one embodiment, the outer diameter of the core body is A, the outer diameter of the fourth tab region is I, satisfying: 25%A≤I≤35%A; and / or, the inner diameter of the third tab region is C, satisfying: 40%A≤C≤75%A.

[0019] In one embodiment, the third electrode tab is connected to the first electrode plate.

[0020] In one embodiment, a plane perpendicular to the axis of the core body is used as the projection plane, and the axial direction of the core body is used as the projection direction. In the projection plane, the projection of the first tab before bending overlaps with the projection of the third tab before bending.

[0021] In one embodiment, the fourth electrode tab is connected to the second electrode plate.

[0022] In one embodiment, a plane perpendicular to the axis of the core body is used as the projection plane, and the axial direction of the core body is used as the projection direction. In the projection plane, the projection of the second tab before bending overlaps at least partially with the projection of the fourth tab before bending.

[0023] In one embodiment, multiple layers of first electrode tabs are bent and stacked to form a first electrode tab region, and multiple layers of second electrode tabs are bent and stacked to form a second electrode tab region. Along the radial direction of the core body, from the center of the core body outward, a first electrode tab region, a second middle ring hollow tab region, and a second electrode tab region are sequentially provided at the first end. The first electrode tab region and the second electrode tab region extend along the circumference of the core to form a closed or open ring.

[0024] In one embodiment, multiple layers of first electrode tabs are bent and stacked to form a first electrode tab region, and multiple layers of second electrode tabs are bent and stacked to form a second electrode tab region. Along the radial direction of the core body, from the center of the core body outward, a second central hollow tab region, a first electrode tab region, and a second electrode tab region are sequentially provided at the first end.

[0025] In one embodiment, the inner diameter of the first tab region is M, and the outer diameter of the core body is A, satisfying: 3%A≤M≤22%A.

[0026] In one embodiment, multiple layers of first electrode tabs are bent and stacked to form a first electrode tab region, and multiple layers of second electrode tabs are bent and stacked to form a second electrode tab region. Along the radial direction of the core body, from the center of the core body outward, the first end is sequentially provided with a first electrode tab region, a second electrode tab region, and a second peripheral hollow tab region.

[0027] In one embodiment, the outer diameter of the second tab region is E, and the outer diameter of the core body is A, satisfying: 85%A≤E<100%A.

[0028] In one embodiment, the outer diameter of the core body is A, the outer diameter of the first tab region is G, satisfying: 35%A≤G≤50%A; and / or, the inner diameter of the second tab region is F, satisfying: 60%A≤F≤75%A.

[0029] In one embodiment, FG ≥ 4 mm.

[0030] In one embodiment, the outer diameter of the second tab region is E, and the inner diameter of the second tab region is F, satisfying: EF≥4mm.

[0031] In one embodiment, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0032] In one embodiment, the first output electrode is the pole assembly, and the second output electrode is the cover plate body. The cover plate body is closed with the housing to seal the receiving cavity. The pole assembly is installed on the cover plate body and electrically connected to the first electrode tab. The cover plate body is provided with a recessed portion, which is electrically connected to the second electrode tab.

[0033] In one embodiment, the recess is provided with a welding plate for welding connection, the welding plate is electrically connected to the second electrode lug, and the thickness of the welding plate is less than the thickness of the area of ​​the cover plate body where the recess is not provided.

[0034] In one embodiment, the battery cell further includes a first current collector and a second current collector, the first current collector and the second current collector being located at the same end of the core, the first current collector being welded to the second tab and the welding plate, and the second current collector being electrically connected to the first tab and the pole assembly.

[0035] In one embodiment, the thickness of the welding plate is H1, the thickness of the first current collector is H2, H2 = bH1, satisfying: 0.5 ≤ b ≤ 1.2.

[0036] In one embodiment, the thickness of the welding plate is H1, and the thickness of the area of ​​the cover plate body without the recess is H, where H1 = aH, satisfying: 0.5 ≤ a ≤ 0.7.

[0037] In one embodiment, the cover plate body has a base plate for defining the bottom of the recess, and a welding plate is disposed on the base plate.

[0038] In one embodiment, the cover plate body further has a side plate connected to the bottom plate to form a recess together with the bottom plate. The bottom plate is electrically connected to the second electrode lug. The thickness of the welding plate is H1, and the thickness of the side plate is H4, wherein cH4=H1, satisfying: 0.3≤c≤0.6.

[0039] In one embodiment, the recessed portion includes a first bent connecting portion and a second bent connecting portion. The first bent connecting portion is connected between the side plate and the bottom plate, and the second bent connecting portion is connected between the side plate and the area of ​​the cover plate body where the recessed portion is not provided. The thickness of the area of ​​the cover plate body where the recessed portion is not provided is H, the radius of curvature of the first bent connecting portion is R1, and the radius of curvature of the second bent connecting portion is R2, wherein R1 = mH and R2 = nH, satisfying: 0.8 ≤ m ≤ 2 and 0.1 ≤ n ≤ 1.

[0040] In one embodiment, R1 = pR2, satisfying: 0.15 ≤ p ≤ 0.5.

[0041] In one embodiment, the recess includes a first bent connection portion, which is connected between the side plate and the bottom plate, and the thickness of the first bent connection portion gradually decreases along the direction from the side plate to the bottom plate.

[0042] In one embodiment, the thickness of the area of ​​the cover plate body without the recess is H, the width of the recess is L1, and the depth of the recess is L2, where L1 = dH and L2 = eH, satisfying: 2.5 ≤ d ≤ 5 and 1.5 ≤ e ≤ 3.5.

[0043] In one embodiment, the recess protrudes toward the receiving cavity.

[0044] In one embodiment, the diameter of the circle containing the outer contour of the orthographic projection of the shell on the horizontal plane is D1, and the diameter of the circle containing the center line of the orthographic projection of the recess on the horizontal plane is D2, where D2 = fD1, satisfying: 0.5 ≤ f ≤ 0.8.

[0045] In one embodiment, the cross-sectional shape of the recess includes any one of U-shape, V-shape, and W-shape.

[0046] In one embodiment, a first insulating member is further included, which is disposed between the first current collector and the second current collector.

[0047] In one embodiment, the cover plate body includes a first cover plate portion and a second cover plate portion; the first cover plate portion is provided with a first hole and an explosion-proof groove, the pole post assembly is inserted into the first hole, and the explosion-proof groove is provided on the outside of the first hole; the second cover plate portion is connected between the outer periphery of the first cover plate portion and the housing; wherein, a recessed portion is provided in the second cover plate portion and adjacent to the explosion-proof groove, and the recessed portion is connected to the second pole lug.

[0048] In one embodiment, the diameter of the circle containing the outer contour of the housing projected along its axial direction is D1, the diameter of the circle containing the center line of the orthographic projection of the explosion-proof markings on the horizontal plane is D3, and the diameter of the circle containing the center line of the orthographic projection of the recess on the horizontal plane is D2, where D3 = a'D1, D2 = fD1, satisfying: 0.4 ≤ a' ≤ 0.75, 0.5 ≤ f ≤ 0.8.

[0049] In one embodiment, the thickness of the cover plate body is H, where D2-D3=2c'H, c'>3.

[0050] In one embodiment, the recess is configured such that one side of the second cover portion is recessed into the receiving cavity.

[0051] In one embodiment, the thickness of the area of ​​the second cover plate without the recess is H, the thickness of the area of ​​the first cover plate without the explosion-proof marking is H6, the marking depth of the explosion-proof marking is H32, and (H6-H32)=qH, satisfying: 0.1≤q≤0.3.

[0052] In one embodiment, the cover plate body has a normal state. In the normal state, the first cover plate portion is further provided with a first groove. The first groove has a first bottom wall and a first inner side wall connected to the first bottom wall. Explosion-proof markings are provided on the first bottom wall.

[0053] In one embodiment, the thickness of the area of ​​the first cover plate without the first groove is H3, the width of the first groove is H40, the depth of the first groove is H50, and the thickness of the area of ​​the first bottom wall without explosion-proof markings is H6, wherein H40 = k'H3, H50 = m'H3, and H6 = n'H3, satisfying: 2≤k'≤5, 1≤m'≤2, and 0.5≤n'≤1.

[0054] In one embodiment, the first inner sidewall is inclined relative to the first bottom wall, and the included angle between the first inner sidewall and the first bottom wall is α, wherein 55°≤α≤135°.

[0055] In one embodiment, the first groove protrudes toward the receiving cavity, and the cover plate body also has an abnormal state, wherein the first cover plate portion of the cover plate body in the abnormal state is flatter than the first cover plate portion of the cover plate body in the normal state.

[0056] In one embodiment, a second insulating member is also included. The first cover plate includes a first connecting plate and a second connecting plate connected to the outer periphery of the first connecting plate. Explosion-proof grooves are provided on the second connecting plate. The second insulating member is provided between the pole assembly and the first connecting plate and abuts against the second connecting plate. A first hole is provided on the first connecting plate.

[0057] In one embodiment, the second insulating member includes a first insulating portion and a second insulating portion, a first connecting plate is located between the first insulating portion and the second insulating portion, and the inner peripheral side of the first insulating portion passes through the first hole and is connected to the inner peripheral side of the second insulating portion; wherein, the second insulating portion is located on the side of the first connecting plate near the receiving cavity, the second connecting plate is recessed toward the receiving cavity to form a recessed structure, and the outer peripheral side of the second insulating portion abuts against the recessed structure.

[0058] In one embodiment, explosion-proof grooves are provided around the first hole.

[0059] In one embodiment, when the air pressure in the receiving cavity is a first air pressure, the pole assembly is disconnected from the core; when the air pressure in the receiving cavity is a second air pressure, the cover plate body cracks at the explosion-proof notch; wherein, the first air pressure is P1, the second air pressure is P2, 1.2 MPa ≤ P1 ≤ 1.8 MPa, and P2 > 1.8 MPa.

[0060] In one embodiment, the first tab, the second tab, and the third tab are die-cut tabs.

[0061] In one embodiment, the die-cut width of the die-cut tab is W0, which satisfies 2mm≤W0≤6mm.

[0062] In one embodiment, the die-cutting angle of the die-cut tab is α0, which satisfies 55°≤α0≤85°.

[0063] In one embodiment, the die-cutting height of the die-cut tab is H0, which satisfies: 5mm≤H0≤7.5mm.

[0064] Secondly, embodiments of this application provide a battery module, which includes a cooling device and the aforementioned battery cell; the cooling device includes a first cooling plate; there are multiple battery cells, each battery cell also includes a third current collector, and the portion of the housing near the third electrode tab is an end plate; wherein, the third current collector is located between the end plate and the third electrode tab and is electrically connected to the third electrode tab, the third current collector includes a heat-conducting part, the heat-conducting part is connected to the end plate, and the side of the end plate away from the winding core is connected to the first cooling plate.

[0065] In one embodiment, the heat-conducting part includes a first heat-conducting surface facing the end plate, the first heat-conducting surface being connected to the end plate, the end plate including a second heat-conducting surface facing the first cooling plate, the second heat-conducting surface being connected to the first cooling plate, the area of ​​the first heat-conducting surface being S1, the area of ​​the second heat-conducting surface being S2, wherein S1:S2 = (0.05~0.25):1.

[0066] In one embodiment, the third current collector is welded to the end plate.

[0067] In one embodiment, the welding area between the third current collector and the end plate is S3, wherein S3:S2 = (0.01~0.05):1.

[0068] In one embodiment, the end plate is formed with a second groove with an opening facing the winding core. The second groove has a second bottom wall and a second inner side wall connected to the second bottom wall. A heat-conducting part is disposed in the second groove and connected to the second bottom wall.

[0069] In one embodiment, the second inner sidewall is inclined relative to the second bottom wall, and the included angle between the second inner sidewall and the second bottom wall is γ, wherein 105°≤γ≤135°.

[0070] In one embodiment, the end plate has a first part and a second part disposed around the first part, and a second groove is formed on the first part; the vertical distance between the second bottom wall and the side of the end plate opposite to the winding core is W1, and the thickness of the second part is W2, wherein W1:W2 = (0.3~0.6):1.

[0071] In one embodiment, the vertical distance between the second bottom wall of the second groove and the side of the end plate facing away from the core is W1, and the thickness of the heat-conducting part is W3, wherein W3:W1 = (0.2~1.2):1.

[0072] In one embodiment, the battery cell further includes a first current collector, and the two ends of the core are provided with tabs of the same polarity. The first current collector is connected to the tabs away from the first cooling plate, and the third current collector is connected to the tabs close to the first cooling plate.

[0073] In one embodiment, the first current collector further includes a current collecting section and a connecting section. The current collecting section is connected to the winding core, and the connecting section is connected between the current collecting section and the heat-conducting section. The connecting section is inclined relative to the heat-conducting section.

[0074] In one embodiment, the included angle between the connecting part and the heat-conducting part is β, wherein 105°≤β≤135°.

[0075] In one embodiment, the side of the end plate facing the first cooling plate is a plane.

[0076] In one embodiment, the cooling device further includes a cooling assembly comprising a plurality of second cooling plates extending from the first cooling plate near the side of the battery cell, the plurality of second cooling plates communicating with the first cooling plate, and the second cooling plates being thermally connected to the radial sidewall of the battery cell.

[0077] Thirdly, embodiments of this application provide a battery pack, which includes a housing and the aforementioned battery module, with the battery module installed inside the housing.

[0078] Fourthly, embodiments of this application provide an electrical device, which includes the aforementioned battery cell, battery module, or battery pack, wherein the battery cell, battery module, or battery pack supplies power to the electrical device.

[0079] The beneficial effects of the embodiments of this application are as follows:

[0080] In the embodiments of this application, by providing a first tab and a second tab at one end of the winding core for positive and negative current collection respectively, and providing a third tab at the other end of the winding core for positive or negative current collection, the current collection area of ​​the electrode connected to the third tab can be increased, thereby increasing the electron conduction path and improving the current collection capacity of the electrode. This enhances the current collection capacity of the battery cell. Attached Figure Description

[0081] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0082] Figure 1 This is a schematic diagram of the battery cell structure provided in an embodiment of this application;

[0083] Figure 2 This is a schematic diagram of the structure of the winding core provided in an embodiment of this application;

[0084] Figure 3 yes Figure 2 Enlarged view of point A in the middle;

[0085] Figure 4 This is a schematic diagram of the structure of the second end provided in an embodiment of this application;

[0086] Figure 5 This is a schematic diagram of another second end structure provided in an embodiment of this application;

[0087] Figure 6 This is a schematic diagram showing the projection relationship between the third electrode and the first electrode before bending, provided in an embodiment of this application.

[0088] Figure 7 This is a schematic diagram showing the projection relationship between the third electrode and the second electrode before bending, provided in an embodiment of this application.

[0089] Figure 8 This is a schematic diagram of the structure of another core provided in an embodiment of this application;

[0090] Figure 9 This is a schematic diagram of the structure of another second end provided in an embodiment of this application;

[0091] Figure 10 This is a schematic diagram showing the projection relationship between the fourth electrode and the second electrode before bending, provided in an embodiment of this application.

[0092] Figure 11This is a schematic diagram of the structure of the first end provided in an embodiment of this application;

[0093] Figure 12 This is a three-dimensional structural schematic diagram of the battery cell provided in an embodiment of this application;

[0094] Figure 13 This is a schematic diagram of the structure of the cover plate body and the pole post assembly in an embodiment of this application;

[0095] Figure 14 yes Figure 1 Enlarged view of point A' in the middle;

[0096] Figure 15 yes Figure 1 Enlarged view of point B in the middle;

[0097] Figure 16 This is a front view of the battery cell provided in an embodiment of this application;

[0098] Figure 17 yes Figure 1 A schematic diagram of the structure of a Chinese battery cell under the first air pressure;

[0099] Figure 18 yes Figure 1 A schematic diagram of another embodiment of the battery cell under the first air pressure;

[0100] Figure 19 yes Figure 1 A schematic diagram of the structure of a battery cell under the second pressure;

[0101] Figure 20 This is a schematic diagram of the structure of the cover plate body and the pole post assembly provided in the embodiments of this application;

[0102] Figure 21 This is a cross-sectional view of the cover plate body provided in an embodiment of this application;

[0103] Figure 22 yes Figure 21 Enlarged view of point D in the middle;

[0104] Figure 23 yes Figure 21 Enlarged view of point E in the middle;

[0105] Figure 24 yes Figure 21 Enlarged view of point C in the middle;

[0106] Figure 25 The embodiments of this application provide schematic diagrams of the electrode structure;

[0107] Figure 26 This is a perspective view of the battery module provided in an embodiment of this application;

[0108] Figure 27 This is a top view of the battery module provided in an embodiment of this application;

[0109] Figure 28 yes Figure 27 Sectional view of EE;

[0110] Figure 29 yes Figure 28 Enlarged diagram of F in the middle;

[0111] Figure 30 This is a front view of a battery cell with a partial cross-section provided in an embodiment of this application;

[0112] Figure 31 yes Figure 30 Enlarged view of point G in the middle;

[0113] Figure 32 yes Figure 31 This is an enlarged view of point H;

[0114] Figure 33 This is a schematic diagram of the structure of the cooling assembly provided in an embodiment of this application;

[0115] Figure 34 This is a schematic diagram of the temperature test points of the battery cell provided in an embodiment of this application;

[0116] Figure 35 This is a schematic diagram of the battery pack structure provided in an embodiment of this application;

[0117] Figure 36 This is a schematic diagram of the structure of the electrical equipment provided in the embodiments of this application.

[0118] Explanation of reference numerals in the attached figures:

[0119] 001-Core; 011-First tab; 111-First tab region; 012-Second tab; 121-Second tab region; 013-Third tab; 131-Third tab region; 014-Fourth tab; 141-Fourth tab region; 015-Core body; 151-First pole piece; 152-Second pole piece; 153-September; 1541-First central loop region; 1542-Second central loop region; 1543-Third central loop region; 1544-First peripheral loop region; 1545- Second peripheral loop area; 1546-Third peripheral loop area; 1547-First middle ring loop area; 1548-Second middle ring loop area; 016-Center hole; 003-Cell; 031-Housing shell; 311-Receiving cavity; 108-Cover plate body; 004-Battery pack; 041-Battery box; 005-Electrical device; 107-Terminal post assembly; 108-Cover plate body; 109-Recess; 110-First current collector; 111a-Second current collector; 112-Base plate; 113-Side plate; 11 6-Welding plate; 117a-First insulating component; 117-First bent connection; 118-Second bent connection; 102-First cover plate; 103-First hole; 104-Explosion-proof groove; 105-Second cover plate; 107b-Welding plate; 108b-First groove; 109b-First bottom wall; 110b-First inner side wall; 111b-First connecting plate; 12b-Second connecting plate; 113b-Second insulating component; 114b-First insulating part; 115b-Second insulating part; 06 0-Battery module; 061-Cooling device; 062-First cooling plate; 066-Third current collector; 067-End plate; 068-Bottom surface; 069-Top surface; 666-Heat-conducting part; T-Temperature test point; 071-First heat-conducting surface; 072-Second heat-conducting surface; 073-Second groove; 074-Second bottom wall; 075-Second inner side wall; 076-Current collector; 077-Connecting part; 078-Cooling assembly; 079-Second cooling plate; 120-Connector; 121a-Third cooling plate. Detailed Implementation

[0120] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0121] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0122] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0123] The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] In the description of the embodiments of this application, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this application is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner.

[0125] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of cell 003 provided in an embodiment of this application. Figure 2 This is a schematic diagram of the structure of the winding core 001 provided in an embodiment of this application. An embodiment of this application provides a battery cell 003. The battery cell includes a housing 031, a winding core 001, a first electrode tab 011, a second electrode tab 012, a third electrode tab 013, a first output electrode, and a second output electrode. The housing 031 has a receiving cavity 311. The winding core 001 is disposed within the receiving cavity 311. The winding core 001 includes a first electrode plate 151, a second electrode plate 152, and a diaphragm 153 disposed between the first electrode plate 151 and the second electrode plate 152, as shown below. Figure 3 As shown, Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 3 for Figure 2 The figure shows a magnified partial cross-sectional view of the area indicated at point A, illustrating the cross-sections of a first electrode 151, a second electrode 152, and a diaphragm 153. The first electrode 151 and the second electrode 152 have opposite polarities. Along the axial direction of the core 001, the core body 015 has a first end and a second end. A first electrode tab 011 is disposed at the first end and connected to the first electrode 151. A second electrode tab 012 is disposed at the first end and connected to the second electrode 152. A third electrode tab 013 is disposed at the second end and connected to either the first electrode 151 or the second electrode 152. A first output electrode and a second output electrode are disposed in the housing, with the first output electrode electrically connected to the first electrode tab and the second output electrode electrically connected to the second electrode tab.

[0126] It can be understood that, of the first and second output terminals, one is the positive output terminal and the other is the negative output terminal. The first and second output terminals can be the battery cell casing, cover plate, or separately installed terminals, etc.

[0127] It is understood that the first electrode 151, the diaphragm 153 and the second electrode 152 are stacked and wound in sequence to form the core 001.

[0128] The first electrode 151 and the second electrode 152 include a coated area with active material and an uncoated area without active material. The first tab 011, the second tab 012, and the third tab 013 can be integrally formed as at least a portion of the uncoated area. In other embodiments, the first tab 011 can be separately soldered to the first electrode 151, the second tab 012 can be separately soldered to the second electrode 152, and the third tab 013 can be separately soldered to either the first electrode 151 or the second electrode 152.

[0129] Furthermore, of the first electrode 151 and the second electrode 152, one is a positive electrode and the other is a negative electrode. The first electrode tab 011 and the second electrode tab 012 have opposite polarities, and the third electrode tab 013 has the same polarity as either the first electrode tab 011 or the second electrode tab 012, and the opposite polarity to the other. For example, the first electrode 151 is a positive electrode, and the second electrode 152 is a negative electrode. Correspondingly, the first electrode tab 011 is a positive electrode tab, and the second electrode tab 012 is a negative electrode tab. The third electrode tab 013 is connected to the first electrode 151 and is a positive electrode tab.

[0130] In this embodiment, by providing a first tab 011 and a second tab 012 at one end of the winding core 001 for positive and negative current collection respectively, and providing a third tab 013 at the other end of the winding core 001 as a positive or negative current collector, the current collection area of ​​the electrode connected to the third tab 013 can be increased, thereby increasing the electron conduction path and improving the current collection capacity of the electrode. Thus, the current collection capacity of the cell 003 can be improved.

[0131] In addition, by setting a third tab 013 to increase the tab area of ​​the electrode connected to the third tab 013, its current carrying capacity can be improved, thereby improving the current carrying capacity of the cell 003.

[0132] Please see Figure 4 or Figure 5 , Figure 4 This is a schematic diagram of the structure of the second end provided in an embodiment of this application. Figure 5 This is a schematic diagram of another second end structure provided by an embodiment of this application. In one embodiment, multiple layers of third tabs 013 are bent and stacked to form a third tab region 131, which extends along the circumference of the core body 015 as a closed or open ring.

[0133] Specifically, the tabs are bent toward the end face of the core so that two radially adjacent tabs are stacked along the axial direction of the core 001.

[0134] Among them, the third electrode area 131 can extend into a closed ring along the circumference of the core body 015, such as Figure 4 As shown; the third electrode tab region 131 can also extend into an open ring along the circumference of the core body 015, that is, the third electrode tab 013 extends into an arc-shaped segment along the circumference of the core body 015. The arc-shaped segment can be one segment or multiple segments, and multiple arc-shaped segments are spaced apart along the circumference of the core body 015, such as... Figure 5 As shown.

[0135] In this embodiment, by extending the third tab 013 along the circumference of the core body 015, on the one hand, the connection length between the third tab 013 and the electrode sheet can be increased, thereby improving the connection strength between the third tab 013 and the electrode sheet, and thus improving the structural reliability of the core 001; on the other hand, the area of ​​the third tab 013 can be increased, thereby increasing the current-carrying area of ​​the core 001, and thus improving the current-collecting capacity of the cell 003.

[0136] When the third tab region 131 extends into a closed ring along the circumference of the core body 015, the area of ​​the third tab 013 can be further increased, thereby increasing the current collection area of ​​the electrode connected to the third tab 013, so as to increase the electron conduction path and thus improve the current collection capacity of the electrode.

[0137] In addition, when the third tab area 131 extends into an open ring along the circumference of the core body 015, the obstruction of the tab flattening at the connection between the third tab 013 and the electrode sheet can be controlled, thereby facilitating the smooth flattening operation of the third tab 013 and improving the tab flattening efficiency.

[0138] Please see Figure 4 In one embodiment, along the radial direction of the core 001, from the center of the core body 015 outward, the second end is sequentially provided with a first central ear area 1541 and a third pole ear area 131.

[0139] The open lug area is the area at the end of the core 001 where no pole lug is provided. Specifically, it is the area at the end of the core 001 that is not covered by the pole lug after it is bent and stacked.

[0140] In addition, the central hole 016 of the core 001 is located at the center of the first central ear area 1541.

[0141] It is understandable that after the electrode sheets are wound into core 001, the third tab 013 is parallel to the axial direction of core 001, occupying a relatively large height dimension, which has an adverse effect on the energy density of the cell. Therefore, the third tab 013 is usually bent towards the center of core 001 to reduce the height space occupied by the third tab 013. However, directly bending the third tab 013 would cause it to block the central hole 016 of core 001.

[0142] Based on this, in this embodiment, by setting the first central ear area 1541, the third electrode ear 013 can be prevented from blocking the middle hole 016 of the winding core 001, thereby ensuring the smooth flow of electrolyte into or out of the middle hole 016, and thus ensuring the wetting efficiency of the battery cell 003.

[0143] In addition, the first central hollow area 1541 can provide expansion space for the thermally expanded third tab 013, so as to avoid the third tab 013 from being subjected to large stress due to the cross-linking after thermal expansion, thereby improving the reliability of the cell 003.

[0144] Please see Figure 4 In one embodiment, the inner diameter of the third tab region 131 is C, and the outer diameter of the core body 015 is A, satisfying: 3%A≤C≤30%A. Wherein, the inner diameter C of the third tab region 131 is the outer diameter of the first central hollow tab region 1541.

[0145] It is understood that the inner diameter C of the third electrode region 131 includes, but is not limited to, 3%A, 6.2%A, 8.3%A, 10%A, 12.1%A, 13.9%A, 14.5%A, 15%A, 17%A, 18.3%A, 20%A, 22.5%A, 23%A, 25.3%A, 27%A, 28.2%A, 29%A, 29.6%A, and 30%A.

[0146] For example:

[0147] When A is 24mm, C includes, but is not limited to, 0.72mm, 0.86mm, 1.08mm, 2.13mm, 2.95mm, 3.11mm, 3.71mm, 4.23mm, 5.25mm, 6.78mm, 7.01mm, and 7.2mm.

[0148] When A is 30mm, C includes, but is not limited to, 0.9mm, 1.06mm, 2.78mm, 3.13mm, 3.85mm, 4.19mm, 5.21mm, 6.23mm, 6.25mm, 7.28mm, 8.29mm, and 9mm.

[0149] When A is 35mm, C includes, but is not limited to, 1.05mm, 2.06mm, 3.78mm, 4.13mm, 4.85mm, 5.19mm, 5.21mm, 6.23mm, 7.25mm, 8.28mm, 9.29mm, and 10.5mm.

[0150] When A is 40mm, C includes, but is not limited to, 1.2mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 8.23mm, 9.75mm, 10.28mm, 11.29mm, and 12mm.

[0151] When A is 45.5mm, C includes, but is not limited to, 1.365mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 8.23mm, 9.25mm, 10.28mm, 12.29mm, and 13.65mm.

[0152] In this embodiment, the above-mentioned limitations can, on the one hand, prevent the inner diameter C of the third tab region 131 from being too small, which would cause the third tab 013 to block the intermediate hole 016 of the core 001, thereby ensuring the smooth flow of electrolyte into or out of the intermediate hole 016, and thus ensuring the wetting efficiency of the cell 003; on the other hand, can prevent the inner diameter C of the third tab region 131 from being too large, which would affect the radial dimension of the third tab 013, thereby ensuring not only the current collection area of ​​the third tab 013 to improve the current collection capacity of the core 001, but also the welding area of ​​the third tab 013, thereby improving the welding stability between the third tab 013 and the current collector plate.

[0153] In addition, by limiting the minimum value of the inner diameter dimension C of the third tab region 131, the first central hollow region 1541 can have enough space to accommodate the thermally expanded third tab 013, thereby avoiding the third tab 013 from intersecting and generating metal debris after thermal expansion.

[0154] In one embodiment, along the radial direction of the core 001, from the center of the core body 015 outward, a third pole ear region 131 and a first peripheral hollow ear region 1544 are sequentially provided at the second end.

[0155] It is understood that, in conjunction with the foregoing embodiments, optionally, along the radial direction of the core 001, from the center of the core body 015 outward, the second end is sequentially provided with a first central loop area 1541, a third pole loop area 131, and a first peripheral loop area 1544.

[0156] In this embodiment, by setting the first peripheral ear area 1544, the third ear 013 can be prevented from exceeding the outer periphery of the core body 015 after the third ear 013 is flattened, thereby controlling the radial dimension of the core 001 to facilitate the core 001 entering the shell.

[0157] In one embodiment, the outer diameter of the third tab region 131 is D, and the outer diameter of the core body 015 is A, satisfying: 65%A≤D≤80%A.

[0158] It is understood that the outer diameter D of the third electrode region 131 includes, but is not limited to, 65%A, 66.2%A, 68.3%A, 70%A, 72.1%A, 73.9%A, 74.5%A, 75%A, 77%A, 78.3%A, 78.5%A, 79%A, 79.5%A, and 80%A.

[0159] For example:

[0160] When A is 24mm, D may include, but is not limited to, 15.6mm, 15.86mm, 16.08mm, 16.13mm, 16.95mm, 17.11mm, 17.71mm, 18mm, 18.25mm, 18.38mm, 18.41mm, and 19.2mm.

[0161] When A is 30mm, D includes, but is not limited to, 19.5mm, 20.4mm, 20.86mm, 21.08mm, 21.95mm, 22.11mm, 22.71mm, 23mm, 23.25mm, 23.38mm, 23.41mm, and 24mm.

[0162] When A is 35mm, D includes, but is not limited to, 22mm, 23mm, 23.38mm, 24.52mm, 25.5mm, 26.08mm, 26.13mm, 26.95mm, 27.11mm, 27.71mm, and 28mm.

[0163] When A is 40mm, D includes, but is not limited to, 26.mm, 26.95mm, 27.11mm, 27.71mm, 28mm, 28.38mm, 28.81mm, 29.4mm, 29.75mm, 30.86mm, 31.08mm, and 32mm.

[0164] When A is 45.5mm, D includes, but is not limited to, 29.575mm, 30.86mm, 31.08mm, 31.13mm, 32.11mm, 32.71mm, 33mm, 34.25mm, 35.38mm, 36mm, and 36.4mm.

[0165] In this embodiment, the above-mentioned arrangement allows the outer periphery of the third tab region 131 and the outer periphery of the core 001 to be radially spaced along the core 001. This ensures that the bent third tab 013 is located within this gap and does not exceed the outer periphery of the core 001, thereby controlling the outer diameter of the core 001 and facilitating its smooth insertion into the housing. On the other hand, it avoids the gap between the outer periphery of the third tab region 131 and the outer periphery of the core 001 being too large, which would affect the area of ​​the third tab 013. This ensures that the current collection capacity and internal resistance of the third tab 013 meet the requirements.

[0166] Please see Figure 6 or Figure 7 , Figure 6 This is a schematic diagram showing the projected relationship between the third electrode 013 and the first electrode 011 before bending, provided in an embodiment of this application. Figure 7This is a schematic diagram illustrating the projection relationship between the third electrode tab 013 and the second electrode tab 012 before bending, provided in an embodiment of this application. In one embodiment, the third electrode tab 013 is connected to the first electrode plate 151. The projection plane is a plane perpendicular to the axis of the core body 015, and the projection direction is the axial direction of the core body 015. In the projection plane, the projection of the first electrode tab 011 before bending at least partially overlaps with the projection of the third electrode tab 013 before bending, such as... Figure 6 As shown; or, the third electrode tab 013 is connected to the second electrode plate 152, with the plane perpendicular to the axis of the core body 015 as the projection plane and the axis of the core body 015 as the projection direction. In the projection plane, the projection of the second electrode tab 012 before bending and the projection of the third electrode tab 013 before bending at least partially overlap, as shown. Figure 7 As shown.

[0167] Optionally, the third electrode 013 is connected to the first electrode 151, and in the projection plane, the projection of the first electrode 011 before bending falls into the projection of the third electrode 013 before bending; or, the third electrode 013 is connected to the second electrode 152, and the projection of the second electrode 012 before bending falls into the projection of the third electrode 013 before bending.

[0168] Specifically, the projection of the root of the first electrode 011 falls within the projection of the root of the third electrode 013, or the projection of the root of the second electrode 012 falls within the projection of the root of the third electrode 013. The root of the electrode is the part where the electrode connects to the coating area.

[0169] In this embodiment, through the above-described arrangement, the third tab 013 and the first tab 011 or the second tab 012 connected to the same electrode sheet have portions opposite each other along the axial direction of the winding core 001. This allows the third tab 013 to collect current and directly transfer the current to the first tab 011 or the second tab 012 connected to the same electrode sheet by moving along the axial direction of the winding core 001, thereby shortening the current collection path of the winding core 001. This improves the current collection capacity of the battery cell 003.

[0170] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of another core 001 provided in an embodiment of this application. In one embodiment, the core 001 further includes a fourth electrode tab 014. The fourth electrode tab 014 is disposed at the second end of the core body 015, and one of the third electrode tab 013 and the fourth electrode tab 014 is connected to the first electrode plate 151, and the other is connected to the second electrode plate 152.

[0171] For example, the third electrode tab 013 is connected to the first electrode plate 151, and the fourth electrode tab 014 is connected to the second electrode plate 152. The first electrode tab 011 is located closer to the center of the winding core 001 than the second electrode tab 012, and the fourth electrode tab 014 is located closer to the center of the winding core 001 than the third electrode tab 013.

[0172] Furthermore, the first electrode 151 is the positive electrode, and the second electrode 152 is the negative electrode. Correspondingly, the first tab 011 is the positive tab, and the second tab 012 is the negative tab.

[0173] In this embodiment, by providing a first tab 011 and a second tab 012 at one end of the core 001 for positive and negative current collection respectively, and by providing a third tab 013 and a fourth tab 014 at the other end of the core 001 for positive and negative current collection respectively, the current collection area of ​​the two types of electrodes in the core 001 can be increased, thereby increasing the electron conduction paths and improving the current collection capacity of the first electrode 151 and the second electrode 152. This further enhances the current collection capacity of the cell 003.

[0174] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of another second end provided in an embodiment of this application. In one embodiment, multiple layers of third tabs 013 are bent and stacked to form a third tab region 131. Multiple layers of fourth tabs 014 are bent and stacked to form a fourth tab region 141. Along the radial direction of the core body 015, from the center of the core body 015 outward, the second end is sequentially provided with a fourth tab region 141, a first central ring hollow tab region 1547, and a third tab region 131. The fourth tab region 141 and the third tab region 131 extend circumferentially along the core body 015 to form closed or open rings, respectively.

[0175] It can be understood that the fourth tab area 141 can extend in a closed ring along the circumference of the core body 015; the fourth tab area 141 can also extend in an open ring along the circumference of the core body 015, that is, the fourth tab 014 extends in an arc-shaped segment along the circumference of the core body 015. The arc-shaped segment can be one segment or multiple segments, and multiple arc-shaped segments are spaced apart along the circumference of the core body 015.

[0176] The insulation between the third tab 013 and the fourth tab 014 can be achieved through spatial insulation isolation via the first middle ring ear area 1547, or by setting an insulating component between the third tab 013 and the fourth tab 014.

[0177] In this embodiment, by extending the third tab 013 and the fourth tab 014 along the circumference of the core body 015, on the one hand, the connection length between the third tab 013 and the fourth tab 014 and the electrode sheet can be increased, thereby improving the connection strength between the third tab 013 and the fourth tab 014 and the electrode sheet, and thus improving the structural reliability of the core 001; on the other hand, the area of ​​the third tab 013 and the fourth tab 014 can be increased, thereby increasing the current-carrying area of ​​the core 001, and thus improving the current-carrying capacity of the cell 003.

[0178] In addition, by setting the first middle ring ear area 1547, a gap can be made between the third ear 013 and the fourth ear 014 to provide expansion space for the third ear 013 and the fourth ear 014 to expand due to heat, so as to avoid excessive clamping force between the third ear 013 and the fourth ear 014 due to thermal expansion, thereby ensuring the reliability of the insulation between the third ear 013 and the fourth ear 014.

[0179] Please see Figure 9 In one embodiment, multiple layers of third tabs 013 are bent and stacked to form a third tab region 131. Multiple layers of fourth tabs 014 are bent and stacked to form a fourth tab region 141. Along the radial direction of the core body 015, from the center of the core body 015 outward, a third central hollow tab region 1543, a fourth tab region 141, and a third tab region 131 are sequentially provided at the second end. The fourth tab region 141 and the third tab region 131 extend along the circumference of the core body 015 to form closed or open annular shapes, respectively.

[0180] In this embodiment, by setting a third central ear area 1543, the central hole of the core 001 can be avoided from being blocked by the fourth tab 014, thereby improving the smoothness of electrolyte flowing out of or into the central hole of the core 001, and thus ensuring the wetting efficiency of the cell 003.

[0181] Please see Figure 9 In one embodiment, the inner diameter of the fourth tab region 141 is J, and the outer diameter of the core body 015 is A, satisfying: 3%A≤J≤22%A.

[0182] It is understood that the inner diameter J of the third electrode region 131 includes, but is not limited to, 3%A, 3.6%A, 43%A, 5%A, 6.2%A, 8.3%A, 10%A, 12.1%A, 13.9%A, 14.5%A, 15%A, 17%A, 18.3%A, 20%A, 21%A, 21.3%A, 21.5%A, and 22%A.

[0183] For example:

[0184] When A is 24mm, J may be, but is not limited to, 0.72mm, 0.86mm, 1.08mm, 1.65mm, 2.13mm, 2.95mm, 3.11mm, 3.71mm, 4.23mm, 5.25mm, 5.78mm, or 5.82mm.

[0185] When A is 30mm, J may be, but is not limited to, 0.9mm, 1.06mm, 2.78mm, 3.13mm, 3.85mm, 4.19mm, 5.21mm, 6.23mm, 6.25mm, 6.38mm, 6.59mm, or 6.6mm.

[0186] When A is 35mm, J may be, but is not limited to, 1.05mm, 2.06mm, 3.78mm, 4.13mm, 4.85mm, 5.19mm, 5.21mm, 6.23mm, 7.25mm, 7.38mm, 7.59mm, or 7.7mm.

[0187] When A is 40mm, J includes, but is not limited to, 1.2mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 7.23mm, 7.75mm, 8.28mm, 8.5mm, and 8.8mm.

[0188] When A is 45.5mm, J includes, but is not limited to, 1.365mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 8.23mm, 9.25mm, 9.88mm, 10mm, and 10.01mm.

[0189] In this embodiment, the above-mentioned limitations can, on the one hand, prevent the inner diameter J of the fourth tab region 141 from being too small, which would cause the fourth tab 014 to block the intermediate hole 016 of the core 001, thereby ensuring the smooth flow of electrolyte into or out of the intermediate hole 016, and thus ensuring the wetting efficiency of the cell 003; on the other hand, can prevent the inner diameter J of the fourth tab region 141 from being too large, which would affect the radial dimension of the fourth tab 014, thereby not only ensuring the current collection area of ​​the fourth tab 014 to improve the current collection capacity of the core 001, but also ensuring the welding area of ​​the fourth tab 014, thereby improving the welding stability between the fourth tab 014 and the current collector plate.

[0190] In addition, by limiting the minimum value of the inner diameter J of the fourth tab region 141, the third central hollow region 1543 can have sufficient space to accommodate the fourth tab 014, thereby preventing the fourth tab 014 from bending and intersecting in the third central hollow region 1543 and generating metal debris.

[0191] Please see Figure 9 In one embodiment, multiple layers of third tabs 013 are bent and stacked to form a third tab region 131. Multiple layers of fourth tabs 014 are bent and stacked to form a fourth tab region 141. Along the radial direction of the core body 015, from the center of the core body 015 outward, a fourth tab region 141, a third tab region 131, and a third peripheral open tab region 1546 are sequentially provided at the second end. The fourth tab region 141 and the third tab region 131 extend circumferentially along the core body 015 as closed or open annular shapes, respectively.

[0192] It is understood that, in conjunction with the foregoing embodiments, optionally, along the radial direction of the core 001, from the center of the core body 015 outward, the second end is sequentially provided with a third central loop area 1543, a fourth pole loop area 141, a first central loop area 1547, a third pole loop area 131, and a third peripheral loop area 1546.

[0193] In this embodiment, by setting a third peripheral ear area 1546, the third ear 013 can be prevented from extending beyond the outer periphery of the core body 015 after it is flattened, thereby controlling the radial dimension of the core 001 to facilitate the core 001 entering the shell.

[0194] Please see Figure 9 In one embodiment, the outer diameter of the third tab region 131 is D, and the outer diameter of the core body 015 is A, satisfying: 85%A≤D<100%A.

[0195] It is understood that the outer diameter D of the third electrode region 131 includes, but is not limited to, 85%A, 86.2%A, 88.3%A, 90%A, 92.1%A, 93.9%A, 94.5%A, 95%A, 97%A, 98.3%A, 98.5%A, 99%A, 99.5%A, and 99.8%A.

[0196] For example:

[0197] When A is 24mm, D may include, but is not limited to, 20.4mm, 20.86mm, 21.08mm, 21.13mm, 21.95mm, 22.11mm, 22.71mm, 23mm, 23.25mm, 23.38mm, 23.41mm, and 23.5mm.

[0198] When A is 30mm, D includes, but is not limited to, 25.5mm, 2586mm, 26.08mm, 26.13mm, 26.95mm, 27.11mm, 27.71mm, 28mm, 28.25mm, 28.38mm, 28.81mm, and 29.4mm.

[0199] When A is 35mm, D includes, but is not limited to, 29.75mm, 30.86mm, 31.08mm, 31.13mm, 31.95mm, 32.11mm, 32.71mm, 33mm, 33.25mm, 33.38mm, 34mm, and 34.3mm; when A is 40mm, D includes, but is not limited to, 34mm, 34.86mm, 35.08mm, 35.13mm, and 35.95mm. m, 36.11mm, 36.71mm, 37mm, 38.25mm, 38.38mm, 39mm, 39.2mm; when A is 45.5mm, D includes, but is not limited to, 38.675mm, 39mm, 39.08mm, 40.13mm, 40.95mm, 41.11mm, 41.71mm, 42mm, 43.25mm, 43.38mm, 44mm, 44.59mm.

[0200] In this embodiment, the above-mentioned arrangement allows the outer periphery of the third tab region 131 and the outer periphery of the core 001 to be radially spaced along the core 001. This ensures that the bent third tab 013 is located within this gap and does not exceed the outer periphery of the core 001, thereby controlling the outer diameter of the core 001 and facilitating its smooth insertion into the housing. On the other hand, it avoids the gap between the outer periphery of the third tab region 131 and the outer periphery of the core 001 being too large, which would affect the area of ​​the third tab 013. This ensures that the current collection capacity and internal resistance of the third tab 013 meet the requirements.

[0201] Please see Figure 9 In one embodiment, the outer diameter of the core body 015 is A, the outer diameter of the fourth tab region 141 is I, satisfying: 25%A≤I≤35%A; and / or, the inner diameter of the third tab region 131 is C, satisfying: 40%A≤C≤75%A.

[0202] Specifically, the outer diameter of the fourth tab region 141 is I, satisfying: 25%A≤I≤35%A, or the inner diameter of the third tab region 131 is C, satisfying: 40%A≤C≤75%A, or the outer diameter of the fourth tab region 141 is I, satisfying: 25%A≤I≤35%A, and the inner diameter of the third tab region 131 is C, satisfying: 40%A≤C≤75%A.

[0203] Among them, the outer diameter dimension I of the fourth pole ear region 141 includes, but is not limited to, 25%A, 25.5%A, 25.9%A, 26%A, 26.8%A, 27%A, 27.33%A, 28%A, 30%A, 31%A, 32%A, 33%A, 34%A, 34.5%A, and 35%A.

[0204] For example:

[0205] When A is 24mm, I includes, but is not limited to, 6mm, 6.06mm, 6.2mm, 6.5mm, 6.95mm, 7.11mm, 7.21mm, 7.3mm, 7.5mm, 7.8mm, 8.02mm, and 8.4mm.

[0206] When A is 30mm, I includes, but is not limited to, 7.5mm, 7.6mm, 8.2mm, 8.5mm, 8.95mm, 9.11mm, 9.21mm, 9.3mm, 9.5mm, 9.8mm, 10.41mm, and 10.5mm.

[0207] When A is 35mm, I includes, but is not limited to, 8.75mm, 8.9mm, 9.2mm, 9.5mm, 9.95mm, 10.11mm, 10.21mm, 10.8mm, 11.05mm, 11.8mm, 12mm, and 12.25mm;

[0208] When A is 40mm, I includes, but is not limited to, 10mm, 10.1mm, 10.2mm, 10.5mm, 10.95mm, 11.11mm, 11.21mm, 11.8mm, 12.05mm, 12.8mm, 13mm, and 14mm.

[0209] When A is 45.5mm, I includes, but is not limited to, 11.375mm, 12.1mm, 12.2mm, 12.5mm, 12.95mm, 13.11mm, 13.21mm, 13.6mm, 13.65mm, 13.8mm, 15mm, and 15.925mm.

[0210] In addition, the inner diameter C of the third pole ear region includes, but is not limited to, 40%A, 45.5%A, 50%A, 53.33%A, 55.9%A, 56%A, 58%A, 60%A, 63%A, 65%A, 68%A, 70%A, 71%A, 74.2%A, and 75%A.

[0211] For example:

[0212] When A is 24mm, C includes, but is not limited to, 9.6mm, 10.06mm, 11.2mm, 12.5mm, 12.95mm, 13.11mm, 14.21mm, 15.3mm, 16.5mm, 16.8mm, 17.41mm, and 18mm.

[0213] When A is 30mm, C includes, but is not limited to, 12mm, 13.6mm, 14.2mm, 15.5mm, 16.95mm, 17.11mm, 17.21mm, 18.3mm, 19.5mm, 20.8mm, 21.41mm, and 22.5mm.

[0214] When A is 35mm, C includes, but is not limited to, 14mm, 15.9mm, 16.2mm, 17.5mm, 18.95mm, 20.11mm, 21.21mm, 22.8mm, 23.05mm, 24.8mm, 25mm, and 26.25mm.

[0215] When A is 40mm, C includes, but is not limited to, 16mm, 17.1mm, 18.2mm, 19.5mm, 20.95mm, 22.11mm, 23.21mm, 24.8mm, 26.05mm, 27.8mm, 29mm, and 30mm.

[0216] When A is 45.5mm, C includes, but is not limited to, 18.2mm, 19.1mm, 20.2mm, 21.5mm, 22.95mm, 23.11mm, 25.21mm, 26.8mm, 30.05mm, 31.8mm, 34mm, and 34.125mm.

[0217] In this embodiment, by limiting the outer diameter I of the fourth tab region 141, the outer diameter of the fourth tab region 141 can be prevented from being too large and affecting the arrangement of the third tab region 131; by limiting the inner diameter C of the third tab region 131, the inner diameter can be prevented from being too small and affecting the arrangement of the fourth tab 014; and by limiting the outer diameter I of the fourth tab region 141 and the inner diameter C of the third tab region 131, there can be a sufficient gap between the fourth tab 014 and the third tab 013, so that the fourth tab 014 and the third tab can be insulated and isolated through the gap, or an insulating element can be provided in the gap.

[0218] In addition, by combining the restrictions on the inner diameter of the fourth tab region 141 and the outer diameter of the third tab region 131 in the aforementioned embodiments, the third tab 013 and the fourth tab 014 can meet the current collection requirements of the winding core 001 and have suitable internal resistance.

[0219] Please see Figure 5 In one embodiment, the third electrode 013 is connected to the first electrode 151.

[0220] With the plane perpendicular to the axis of the core body 015 as the projection plane and the axis of the core body 015 as the projection direction, the projection of the first tab 011 before bending and the projection of the third tab 013 before bending partially overlap in the projection plane.

[0221] The first tab 011 is positioned closer to the center of the core 001 than the second tab 012. The fourth tab 014 is positioned closer to the center of the core 001 than the third tab 013. Along the axial direction of the core 001, the side of the first tab region 111 near the outer periphery of the core 001 is positioned opposite the side of the third tab region 131 near the center of the core 001.

[0222] In this embodiment, the above-described arrangement allows for a portion of the third tab 013 and the first tab 011 that are axially opposite each other along the winding core 001. This allows the third tab 013 to directly transfer current to the first tab 011 by moving axially along the winding core 001 after collecting current, thereby shortening the current collection path of the winding core 001. This improves the current collection capacity of the battery cell 003.

[0223] Please see Figure 10 , Figure 10 This is a schematic diagram showing the projected relationship between the fourth electrode 014 and the second electrode 012 before bending, according to an embodiment of this application. In one embodiment, the fourth electrode 014 is connected to the second electrode 152.

[0224] With the plane perpendicular to the axis of the core body 015 as the projection plane and the axis of the core body 015 as the projection direction, the projection of the second tab 012 before bending and the projection of the fourth tab 014 before bending are at least partially overlapped in the projection plane.

[0225] It is understandable that the projection of the root of the second electrode 012 overlaps with the projection of the root of the fourth electrode 014.

[0226] The first tab 011 is positioned closer to the center of the core 001 than the second tab 012. The fourth tab 014 is positioned closer to the center of the core 001 than the third tab 013. Along the axial direction of the core 001, the side of the fourth tab region 141 near the outer periphery of the core 001 is positioned opposite the side of the second tab region 121 near the center of the core 001.

[0227] In this embodiment, the above-described arrangement allows for a portion of the fourth tab 014 and the second tab 012 that are axially opposite each other along the winding core 001. This allows the fourth tab 014 to directly transfer current to the second tab 012 after collecting current, thus shortening the current collection path of the winding core 001. Consequently, the current collection capacity of the cell 003 can be improved.

[0228] Please see Figure 11 , Figure 11 This is a schematic diagram of the structure of the first end provided in an embodiment of this application. In one embodiment, multiple layers of first tabs 011 are bent and stacked to form a first tab region 111. Multiple layers of second tabs 012 are bent and stacked to form a second tab region 121. Along the radial direction of the core body 015, from the center of the core body 015 outward, the first end is sequentially provided with a first tab region 111, a second central loop tab region 1548, and a second tab region 121. The first tab region 111 and the second tab region 121 extend along the circumference of the core 001 as either closed or open annular shapes.

[0229] Among them, the first tab region 111 and the second tab region 121 can extend into a closed ring along the circumference of the core body 015, such as Figure 11 As shown; the first tab area 111 and the second tab area 121 can also extend into an open ring along the circumference of the core body 015, that is, the first tab area 111 and the second tab area 121 extend into an arc-shaped segment along the circumference of the core body 015. The arc-shaped segment can be one segment or multiple segments, and multiple arc-shaped segments are spaced apart along the circumference of the core body 015.

[0230] In this embodiment, by extending the first tab area 111 and the second tab area 121 along the circumference of the core body 015, not only can the connection length between the first tab 011 and the first electrode 151 and the connection length between the second tab 012 and the second electrode 152 be increased, thereby improving the positional stability of the first tab 011 and the second tab 012; the area of ​​the first tab 011 and the second tab 012 can also be increased, thereby improving the current collection capacity of the first tab 011 and the second tab 012, and thus improving the current collection capacity of the battery cell 003.

[0231] Please see Figure 11 In one embodiment, multiple layers of first tabs 011 are bent and stacked to form a first tab region 111. Multiple layers of second tabs 012 are bent and stacked to form a second tab region 121. Along the radial direction of the core body 015, from the center of the core body 015 outward, a second central hollow tab region 1542, a first tab region 111, and a second tab region 121 are sequentially provided at the first end.

[0232] In this embodiment, by setting a second central ear area 1542, the first electrode ear 011 can be prevented from blocking the middle hole of the winding core 001, thereby ensuring the smooth flow of electrolyte into or out of the middle hole, and thus ensuring the wetting efficiency of the battery cell 003.

[0233] Please see Figure 11 In one embodiment, the inner diameter of the first tab region 111 is M, and the outer diameter of the core body 015 is A, satisfying: 3%A≤M≤22%A.

[0234] It is understood that the inner diameter M of the third electrode region 131 includes, but is not limited to, 3%A, 3.6%A, 43%A, 5%A, 6.2%A, 8.3%A, 10%A, 12.1%A, 13.9%A, 14.5%A, 15%A, 17%A, 18.3%A, 20%A, 21%A, 21.3%A, 21.5%A, and 22%A.

[0235] For example:

[0236] When A is 24mm, M includes, but is not limited to, 0.72mm, 0.86mm, 1.08mm, 1.65mm, 2.13mm, 2.95mm, 3.11mm, 3.71mm, 4.23mm, 5.25mm, 5.78mm, and 5.82mm.

[0237] When A is 30mm, M includes, but is not limited to, 0.9mm, 1.06mm, 2.78mm, 3.13mm, 3.85mm, 4.19mm, 5.21mm, 6.23mm, 6.25mm, 6.38mm, 6.59mm, and 6.6mm.

[0238] When A is 35mm, M includes, but is not limited to, 1.05mm, 2.06mm, 3.78mm, 4.13mm, 4.85mm, 5.19mm, 5.21mm, 6.23mm, 7.25mm, 7.38mm, 7.59mm, and 7.7mm.

[0239] When A is 40mm, M includes, but is not limited to, 1.2mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 7.23mm, 7.75mm, 8.28mm, 8.5mm, and 8.8mm.

[0240] When A is 45.5mm, M includes, but is not limited to, 1.365mm, 2.06mm, 3.78mm, 4.13mm, 5.85mm, 6.19mm, 7.21mm, 8.23mm, 9.25mm, 9.88mm, 10mm, and 10.01mm.

[0241] In this embodiment, the above-mentioned limitations can, on the one hand, prevent the inner diameter M of the first tab region 111 from being too small, which would cause the first tab 011 to block the intermediate hole 016 of the core 001, thereby ensuring the smooth flow of electrolyte into or out of the intermediate hole 016, and thus ensuring the wetting efficiency of the core 001; on the other hand, can prevent the inner diameter M of the first tab region 111 from being too large, which would affect the radial dimension of the first tab 011, thereby ensuring not only the current collection area of ​​the first tab 011 to improve the current collection capacity of the core 001, but also the welding area of ​​the first tab 011, thereby improving the welding stability between the first tab 011 and the current collector plate.

[0242] In addition, by limiting the minimum value of the inner diameter dimension M of the first tab region 111, the second central hollow region 1542 can have a sufficient space to accommodate the thermally expanded first tab 011, thereby avoiding the generation of metal debris in the second central hollow region 1542 after the first tab 011 expands due to heat.

[0243] Please see Figure 11 In one embodiment, multiple layers of first tabs 011 are bent and stacked to form a first tab region 111. Multiple layers of second tabs 012 are bent and stacked to form a second tab region 121. Along the radial direction of the core body 015, from the center of the core body 015 outward, a first tab region 111, a second tab region 121, and a second peripheral loop region 1545 are sequentially provided at the first end.

[0244] In conjunction with the foregoing embodiments, optionally, along the radial direction of the core 001, from the center of the core body 015 outward, the second end is sequentially provided with a second central loop area 1542, a first pole loop area 111, a second middle loop area 1548, a second pole loop area 121 and a second peripheral loop area 1545.

[0245] In this embodiment, by setting a second peripheral ear area 1545, the second ear 012 can be prevented from extending beyond the outer periphery of the core body 015 after it is flattened, thereby controlling the radial dimension of the core 001 to facilitate the core 001 entering the shell.

[0246] Please see Figure 11 In one embodiment, the outer diameter of the second tab region 121 is E, and the outer diameter of the core body 015 is A, satisfying: 85%A≤E<100%A.

[0247] It is understood that the outer diameter E of the second tab region 121 includes, but is not limited to, 85%A, 86.2%A, 88.3%A, 90%A, 92.1%A, 93.9%A, 94.5%A, 95%A, 97%A, 98.3%A, 98.5%A, 99%A, 99.5%A, and 99.8%A.

[0248] For example:

[0249] When A is 24mm, E includes, but is not limited to, 20.4mm, 20.86mm, 21.08mm, 21.13mm, 21.95mm, 22.11mm, 22.71mm, 23mm, 23.25mm, 23.38mm, 23.41mm, and 23.52mm.

[0250] When A is 30mm, E includes, but is not limited to, 25.5mm, 2586mm, 26.08mm, 26.13mm, 26.95mm, 27.11mm, 27.71mm, 28mm, 28.25mm, 28.38mm, 28.81mm, and 29.4mm.

[0251] When A is 35mm, E includes, but is not limited to, 29.75mm, 30.86mm, 31.08mm, 31.13mm, 31.95mm, 32.11mm, 32.71mm, 33mm, 33.25mm, 33.38mm, 34mm, and 34.3mm; when A is 40mm, E includes, but is not limited to, 34mm, 34.86mm, 35.08mm, 35.13mm, and 35.95mm. m, 36.11mm, 36.71mm, 37mm, 38.25mm, 38.38mm, 39mm, 39.2mm; when A is 45.5mm, E includes, but is not limited to, 38.675mm, 39mm, 39.08mm, 40.13mm, 40.95mm, 41.11mm, 41.71mm, 42mm, 43.25mm, 43.38mm, 44mm, 44.59mm.

[0252] In this embodiment, the above-mentioned arrangement allows the outer periphery of the second tab region 121 and the outer periphery of the core 001 to be radially spaced along the core 001. This ensures that the bent second tab 012 is located within this gap and does not exceed the outer periphery of the core 001, thereby controlling the outer diameter of the core 001 and facilitating its smooth insertion into the housing. On the other hand, it prevents the gap between the outer periphery of the second tab region 121 and the outer periphery of the core 001 from being too large, which would affect the area of ​​the second tab 012. This ensures that the current collection capacity and internal resistance of the second tab 012 meet the requirements.

[0253] In one embodiment, the outer diameter of the core body 015 is A, the outer diameter of the first tab region 111 is G, satisfying: 35%A≤G≤50%A; and / or, the inner diameter of the second tab region 121 is F, satisfying: 60%A≤F≤75%A.

[0254] Specifically, the outer diameter G of the first tab region 111 satisfies: 35%A≤G≤50%A; or, the inner diameter F of the second tab region 121 satisfies: 60%A≤F≤75%A; or, the outer diameter G of the first tab region 111 satisfies: 35%A≤G≤50%A, and the inner diameter F of the second tab region 121 satisfies: 60%A≤F≤75%A.

[0255] The outer diameter G of the first tab region 111 includes, but is not limited to, 35%A, 35.5%A, 36.9%A, 37%A, 38.8%A, 40%A, 42.33%A, 44.8%A, 45%A, 46.1%A, 47.2%A, 48.3%A, 49.4%A, 49.5%A, and 50%A.

[0256] For example:

[0257] When A is 24mm, G includes, but is not limited to, 8.4mm, 8.9mm, 9.2mm, 9.5mm, 9.95mm, 10.11mm, 10.21mm, 10.8mm, 11.05mm, 11.8mm, 11.9mm, and 12mm.

[0258] When A is 30mm, G includes, but is not limited to, 10.5mm, 10.95mm, 11.11mm, 11.21mm, 11.8mm, 12.05mm, 12.8mm, 13mm, 14mm, 14.5mm, 14.8mm, and 15mm.

[0259] When A is 35mm, G includes, but is not limited to, 12.25mm, 12.95mm, 13.11mm, 13.21mm, 13.8mm, 13.9mm, 15mm, 15.925mm, 16.05mm, 16.8mm, 17mm, and 17.5mm.

[0260] When A is 40mm, G includes, but is not limited to, 14mm, 14.1mm, 15.2mm, 16mm, 16.95mm, 17.11mm, 17.61mm, 18mm, 18.05mm, 18.8mm, 19mm, and 20mm.

[0261] When A is 45.5mm, G includes, but is not limited to, 15.925mm, 16.1mm, 16.2mm, 16.5mm, 17mm, 17.11mm, 17.8mm, 18.05mm, 18.8mm, 19mm, 20mm, and 22.75mm.

[0262] In addition, the inner diameter F of the second tab region 121 includes, but is not limited to, 60%A, 61.5%A, 63%A, 64.33%A, 65.9%A, 66%A, 68%A, 69%A, 70.3%A, 71.5%A, 72.8%A, 73%A, 74%A, 74.2%A, and 75%A.

[0263] For example:

[0264] When A is 24mm, F includes, but is not limited to, 14.4mm, 14.6mm, 14.92mm, 15mm, 15.15mm, 15.81mm, 16mm, 16.3mm, 16.5mm, 16.8mm, 17.41mm, and 18mm.

[0265] When A is 30mm, F includes, but is not limited to, 18mm, 18.1mm, 18.2mm, 18.5mm, 19mm, 19.11mm, 19.21mm, 20.3mm, 10.5mm, 21.8mm, 21.91mm, and 22.5mm.

[0266] When A is 35mm, F includes, but is not limited to, 21mm, 21.9mm, 22.2mm, 22.5mm, 22.95mm, 23.11mm, 24.21mm, 24.8mm, 25.05mm, 25.8mm, 26mm, and 26.25mm.

[0267] When A is 40mm, F includes, but is not limited to, 24mm, 24.1mm, 25.2mm, 26.5mm, 26.95mm, 27.11mm, 27.21mm, 27.8mm, 28.05mm, 28.8mm, 29mm, and 30mm.

[0268] When A is 45.5mm, F includes, but is not limited to, 27.3mm, 28.1mm, 29.2mm, 29.5mm, 29.95mm, 30.11mm, 31.21mm, 31.8mm, 32.05mm, 33.8mm, 34mm, and 34.125mm.

[0269] In this embodiment, by limiting the outer diameter G of the first tab region 111, the outer diameter of the first tab region 111 can be prevented from being too large and affecting the arrangement of the second tab region 121; by limiting the inner diameter F of the second tab region 121, the inner diameter can be prevented from being too small and affecting the arrangement of the first tab 011; and by limiting the outer diameter G of the first tab region 111 and the inner diameter F of the second tab region 121, there can be a sufficient gap between the first tab 011 and the second tab 012, so that the first tab 011 and the second tab can be insulated and isolated through the gap, or an insulating element can be provided in the gap.

[0270] In addition, by combining the restrictions on the inner diameter of the first tab region 111 and the outer diameter of the second tab region 121 in the aforementioned embodiments, the first tab 011 and the second tab 012 can meet the current collection requirements of the winding core 001 and have suitable internal resistance.

[0271] Optionally, the third tab 013 is connected to the first electrode 151, and the inner diameter C of the third tab region 131 is not greater than the outer diameter G of the first tab region 111. Therefore, after the third tab 013 collects current, it can directly move along the axial direction of the winding core 001 to transfer the current to the first tab 011, thereby shortening the current collection path and enhancing the current collection effect.

[0272] Similarly, the fourth tab 014 is connected to the second tab 152, and the inner diameter F of the second tab region 121 is not greater than the outer diameter I of the fourth tab region 141. Therefore, after the fourth tab 014 collects current, it can directly move along the axial direction of the winding core 001 to transfer the current to the second tab 012, thereby shortening the current collection path and enhancing the current collection effect.

[0273] In one embodiment, FG ≥ 4 mm.

[0274] For example, the difference between the inner diameter F of the second tab region 121 and the outer diameter G of the first tab region 111 includes, but is not limited to, 4mm, 4.1mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.8mm, and 5mm.

[0275] In this embodiment, the above-mentioned limitations allow for a minimum 4mm gap between the inner diameter F of the second tab region 121 and the outer diameter G of the first tab region 111, so that the first tab 011 and the second tab can be insulated and isolated by this gap, or so that the gap provides sufficient space for installing insulating components, thereby improving the convenience of configuring insulating components.

[0276] In one embodiment, the outer diameter of the second tab region 121 is E, and the inner diameter of the second tab region 121 is F, satisfying: EF≥4mm.

[0277] For example, the difference between the outer diameter E of the second tab region 121 and the inner diameter F of the second tab region 121 includes, but is not limited to, 4mm, 4.1mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.8mm, and 5mm.

[0278] In this embodiment, the above-mentioned limitations allow the second tab 012 to have a sufficient area, which not only enables the current collection capacity of the second tab 012 to meet the current collection requirements of the core 001, but also allows the second tab 012 to have a suitable welding area, thereby improving the ease of operation of welding the second tab 012 to the current collector plate.

[0279] The technical solutions and effects of this application will be described in detail below through specific embodiments. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0280] This embodiment aims to examine the impact of applying the winding core to the battery on battery performance.

[0281] The specific details of the test content for the embodiment are as follows:

[0282] I. Test-related instructions

[0283] The following test method is the DCR test, namely, the Direct Current Resistance test.

[0284] The equipment used for testing is a power battery tester, model CTE-8008-5V200A.

[0285] The test environment temperature was 25±2℃.

[0286] The main operation process of the test is as follows:

[0287] First, the nominal capacity is set at 1C = 32.4A, and the standard charge / discharge capacity is set at 1 / 3C, i.e., 10.8Ah. The average value of the actual capacitance measured after 3 charge / discharge cycles is taken as the calibrated capacity C0.

[0288] C0=(∑I n*Tn+∑I'n*T'n) / 6,

[0289] In this formula: n is a natural number, and n∈(1,3);

[0290] In is the charging current for the nth time;

[0291] Tn is the charging time for the nth time;

[0292] I'n is the nth discharge current;

[0293] T'n is the time of the nth discharge.

[0294] Then charge the cell to 4.25V with a constant current and constant voltage of 1 / 3C, and cut off the current of 0.05C; then adjust the state of charge of the cell to 50% SOC with a discharge current of 1 / 3C0, and let the cell stand for 1 hour.

[0295] Next, with the cell at a state of charge (SOC) of 50%, the cell was discharged at a constant current of 2C0 for 30 seconds. The voltage difference δU_discharge and the discharge current I_discharge were recorded before and after the discharge. Based on the formula: DCR_discharge = δU_discharge / I_discharge, the battery charging DCR with the cell at a state of charge (SOC) of 50% was obtained.

[0296] Meanwhile, with the cell's state of charge at 50% SOC, it was charged at a constant current of 2C0 for 30 seconds, and the voltage difference δU_charging and the charging current I_charging before and after charging were recorded. Based on the formula: DCR_charging = δU_charging / I_charging, the battery discharge DCR with the cell's state of charge at 50% SOC was obtained.

[0297] II. Test Results

[0298] The test results were all based on cells with an outer core diameter A of 45.1 mm, a core center hole diameter of 5 mm, a core height of 88.3 ± 0.3 mm, and a core axial dimension of 4–5 mm before the tabs were bent.

[0299] 2.1 Setting up a control group

[0300] The control group consists of battery cells from related technologies that only have positive and negative tabs at the first end. Test data is as follows:

[0301]

[0302] Table 1. Parameters and validation results of control groups 1 and 2

[0303] According to Table 1,

[0304] (1) In control group 1, the positive tab is located at the same end of the core, the area of ​​the positive tab is 1002.4 mm2, the area of ​​the negative tab is 1067.6 mm2, and the battery charging DCR is 3.72 mΩ and the battery discharging DCR is 3.69 mΩ when the cell is at 50% SOC.

[0305] (2) In control group 2, the positive tab is located at the same end of the core. When the area of ​​the positive tab is 235 mm2 and the area of ​​the negative tab is 1067.6 mm2, the battery charging DCR is 4.18 mΩ and the battery discharging DCR is 3.95 mΩ when the state of charge of the cell is 50%.

[0306] 2.2 Based on the control group, the parameter settings of the core were varied using the single variable method. The variable parameter tables and verification results of each embodiment are shown in Tables 3 and 4.

[0307] 2.21 Under the premise that the rest of the structure is the same, a third electrode tab is added to the second end of the core. The third electrode tab is the positive electrode tab.

[0308] Based on the formulas: 3%A≤C≤30%A and 65%A≤D≤80%A, the ranges of the inner and outer diameters of the third electrode region formed by bending and stacking the positive electrode tabs are as follows: inner diameter C of the positive electrode tab: 1.353mm≤C≤13.53mm; outer diameter D of the positive electrode tab: 29.315mm≤D≤36.08mm. The area of ​​the negative electrode tab remains unchanged, and the total areas of the positive electrode tabs are 1002.4mm² and 999.9mm², respectively. Correspondingly, C is selected as 3mm and 13.5mm, and D as 31.4mm and 34mm, respectively.

[0309] Based on the above, the test data is as follows:

[0310]

[0311] Table 2. Parameters and verification results of the bottom positive electrode tab

[0312] Comparing Table 2 and Table 1, we can draw the following conclusions:

[0313] (1) The total area of ​​the positive electrode tab in Control Group 1 is equal to that in Example 1, both being 1002.4 mm². The total area of ​​the negative electrode tab in Control Group 1 is also equal to that in Example 1, both being 1067.6 mm². However, the battery charging DCR of Control Group 1 is 3.72 mΩ, and the battery discharging DCR is 3.69 mΩ. The battery charging DCR of Example 1 is 3.56 mΩ, and the battery discharging DCR is 3.68 mΩ. Therefore, it can be seen that the battery charging DCR of Example 1 is lower than that of Control Group 1, and the battery discharging DCR of Example 1 is also lower than that of Control Group 1.

[0314] Therefore, under the premise that the total area of ​​the positive and negative tabs are equal, placing the positive tab at the first end and the second end respectively can reduce the charging DCR of the battery and help reduce the discharging DCR of the battery, thereby improving the overcurrent capacity.

[0315] (2) The total area of ​​the negative electrode tab in Example 2 is the same as that in Control Group 1, both being 1067.6 mm². However, the total area of ​​the positive electrode tab in Example 2 is 999.9 mm², which is lower than that in Control Group 1 (1002.4 mm²). Furthermore, the battery charging DCR of Example 2 is 3.51 mΩ, which is lower than that of Control Group 1 (3.72 mΩ), and the battery discharging DCR of Example 2 is 3.64 mΩ, which is lower than that of Control Group 1 (3.68 mΩ).

[0316] Therefore, under the premise that the total area of ​​the negative tabs is equal, placing the positive tabs at both ends of the winding core, compared to placing the positive tabs only at one end of the winding core, can still reduce the charging DCR of the battery and help reduce the discharging DCR of the battery, thereby improving the overcurrent capacity, even if the total area of ​​the positive tabs in the former is slightly lower than that in the latter.

[0317] (3) According to the comparison of Example 1 or Example 2 and Control Group 2, it can be seen that under the premise that the positive electrode tab and the negative electrode tab provided at the first end of the winding core have equal areas, the positive electrode tab provided at the second end of the winding core to increase the total area of ​​the positive electrode tab can reduce the charging DCR of the battery and help reduce the discharging DCR of the battery, thereby improving the overcurrent capacity.

[0318] (4) According to the comparison of Example 1 and Example 2, the larger the area of ​​the positive electrode tab at the second end of the winding core, the larger the total area of ​​the positive electrode tab, and correspondingly, the smaller the battery charging DCR and battery discharging DCR, thereby improving the overcurrent capacity.

[0319] 2.22 Under the premise that the rest of the structure is the same, a third electrode tab is added to the second end of the core, and the third electrode tab is a positive electrode tab. At the same time, the inner diameter of the third electrode tab area is reduced so that the area of ​​the positive electrode tab increases sequentially. The test data are as follows:

[0320]

[0321] Table 3. Parameters and verification results for the bottom positive electrode tab

[0322] As shown in Table 3, with the area of ​​the positive and negative tabs at the first end remaining unchanged, as the area of ​​the positive tab at the second end increases from 874.2 mm2 to 938.5 mm2 and 1067.6 mm2, the battery charging DCR decreases from 3.45 mΩ to 3.25 mΩ and 3.06 mΩ, respectively. Correspondingly, the battery discharging DCR decreases from 3.35 mΩ to 3.30 mΩ and 3.15 mΩ, respectively.

[0323] Therefore, by increasing the area of ​​the positive tab at the second end, the total area of ​​the positive tab will be increased, which will reduce the charging DCR of the battery and help reduce the discharging DCR of the battery, thereby improving the overcurrent capacity.

[0324] 2.23 Based on the aforementioned embodiments, a fourth electrode tab is added to the second end of the winding core. The fourth electrode tab is a negative electrode tab, and the area of ​​the negative electrode tab increases sequentially.

[0325] Based on the formulas: 40%A≤C≤75%A and 85%A≤D<100%A, the ranges of the inner and outer diameters of the third electrode region formed by the stacked positive electrode tabs are as follows: inner diameter C of the positive electrode tab: 18.4mm≤C≤33.825mm, outer diameter D of the positive electrode tab: 38.353mm≤D<45.1mm. Specifically, C is selected as 33mm, 28mm, 25mm, and 22.5mm, and D is selected as 45mm, 42mm, 40mm, and 38.5mm.

[0326] According to the formulas 3%A≤J≤22%A and 25%A≤I≤35%A, the ranges of the inner and outer diameters of the fourth electrode region formed by the stacked negative electrode tabs are as follows: inner diameter J of the negative electrode tab: 1.353mm≤J≤9.922mm, outer diameter I of the negative electrode tab: 11.275mm≤I<15.785mm. Specifically, I is selected as 12mm, 13mm, 14mm, and 15mm, and J is 8mm. Correspondingly, the areas of the negative electrode tabs at the second end are 64.2mm², 82.4mm², 103.6mm², and 126.3mm², respectively.

[0327] Based on the above, the test data is as follows:

[0328]

[0329]

[0330] Table 4. Parameters and verification results of the negative electrode tab at the bottom.

[0331] Based on Table 4, the following conclusions can be drawn:

[0332] A comparison of Examples 6, 7, 8, and 9 shows that, under the premise that the areas of the positive and negative electrodes at the first end are equal and the areas of the positive electrode tabs at the second end are equal, when the area of ​​the negative electrode tabs at the second end increases sequentially from 62.4 mm² in Example 6 to 82.4 mm² in Example 7, 103.6 mm² in Example 8, and 126.3 mm² in Example 9, the battery discharge DCR decreases sequentially from 3.32 mΩ in Example 6 to 3.27 mΩ in Example 7, 3.18 mΩ in Example 8, and 2.95 mΩ in Example 9; correspondingly, the battery charging DCR decreases sequentially from 3.43 mΩ in Example 6 to 3.39 mΩ in Example 7, 3.35 mΩ in Example 8, and 3.30 mΩ in Example 9.

[0333] Therefore, by increasing the area of ​​the negative tab at the second end, the total area of ​​the negative tab can be increased, thereby reducing the battery discharge DCR and helping to reduce the battery charging DCR, thus improving the overcurrent capacity.

[0334] In related technologies, to achieve simultaneous output of positive and negative electrodes on the same side of the battery cell, the cell's cover plate serves as one output electrode, and a terminal post passing through the cover plate serves as the other output electrode (an insulating component is installed between the terminal post and the cover plate). The terminal post is electrically connected to an electrode of one polarity, and the cover plate is electrically connected to an electrode of the other polarity. When the internal air pressure of the battery cell changes, the cover plate is prone to deformation and detachment from the electrode. This results in the battery cell failing to output power normally under normal operating conditions.

[0335] In view of this, embodiments of this application also provide a battery cell; the following will be combined with the main appendices Figures 12 to 16 A detailed description of the battery cell is provided.

[0336] In one embodiment, the first output electrode is the electrode post assembly 107. The second output electrode is the cover plate body 108. The cover plate body 108 covers the housing 031 to seal the receiving cavity; the electrode post assembly 107 is mounted on the cover plate body 108 and electrically connected to the first electrode tab 011. The cover plate body 108 is provided with a recess 109, which is electrically connected to the second electrode tab 012.

[0337] The recessed portion 109 is electrically connected to the second electrode 152, thereby connecting the cover plate body 108 to the core 001, so that the cover plate body 108 serves as an output electrode of one polarity; while the pole assembly 107 is electrically connected to the first electrode 151, so that the pole assembly serves as an output electrode of another polarity.

[0338] In this embodiment, by providing a recessed portion 109 on the cover plate body 108, the surface area of ​​the cover plate body 108 is increased. Therefore, when the cover plate body 108 is under pressure, the recessed portion 109 can absorb and disperse a portion of the pressure, thereby improving the impact resistance of the cover plate body 108. This also improves the deformation resistance of the cover plate body 108, preventing deformation under stress and thus preventing the cover plate body 108 from detaching from the second electrode 152, allowing the battery cell 003 to output power normally.

[0339] When the recess 109 protrudes from the surface of the cover plate body 108, the recess 109 can also serve as a reinforcing rib to increase the local rigidity of the cover plate body 108, thereby reducing bending and deformation when the cover plate body 108 is under pressure.

[0340] It should be noted that when the internal pressure of cell 003 becomes too high and the outer casing of cell 003 is to be prevented from cracking, the explosion-proof valve configured on cell 003 will open or the explosion-proof groove will break, thereby releasing the excessively high pressure gas inside cell 003 through the explosion-proof valve or the broken explosion-proof groove.

[0341] Furthermore, the second electrode 152 and the first electrode 151 have opposite polarities; that is, one of the second electrode 152 and the first electrode 151 is a positive electrode, and the other is a negative electrode. In this embodiment, the second electrode 152 is a negative electrode, and the first electrode 151 is a positive electrode. Therefore, the cover plate body 108 serves as the negative output terminal, and the electrode post assembly 107 serves as the positive output terminal.

[0342] In one embodiment, please refer to Figure 1 and Figure 13 The recess 109 is provided with a welding plate 116 for welding connection, and the welding plate 116 is electrically connected to the second electrode tab 012. More specifically, considering the difficulty of welding, the thickness of the welding plate 116 is less than the thickness of the area of ​​the cover plate body 108 where the recess 109 is not provided. With this configuration, the thickness of the welding plate 116 is reduced, and during the welding process, the welding energy can penetrate the welding plate 116 more easily, thus reducing the difficulty of welding.

[0343] It should be noted that the connection method between the recess 109 and the second electrode 152 is not limited, and the connection method between the pole assembly 107 and the first electrode 151 is not limited; for example, in one embodiment, in order to shorten the current collection path, the recess 109 is connected to the second electrode 152, and the pole assembly 107 is connected to the first electrode 151.

[0344] In another embodiment, please refer to Figure 14 In order to ensure connection strength and improve the stability of cell 003, cell 003 includes a first current collector 110, which is disposed between the second electrode 152 and the welding plate 116, and is welded to the second electrode 152 and the welding plate 116.

[0345] It is understandable that in the actual connection process, the first current collector 110 is first welded to the second electrode 152, and then the cover plate body 108 is placed on the housing 031, the recess 109 corresponds to the first current collector 110, and then the welding plate 116 is welded to the first current collector 110. This arrangement ensures the connection strength and improves the stability of the cell 003.

[0346] Additionally, please see Figure 15The winding core 001 also includes a second current collector 111a, which is disposed between the first electrode 151 and the electrode post assembly 107, and is electrically connected to both the first electrode 151 and the electrode post assembly 107. Furthermore, to ensure connection strength, the second current collector 111a is welded to the first electrode 151 and also welded to the electrode post assembly 107.

[0347] In this embodiment, the first current collector 110 and the second current collector 111a are located at the same end of the winding core 001. The positive and negative terminals of the battery cell 003 are located on the same side of the winding core 001 to facilitate current collection from one side of the battery cell 003. Thus, compared to a structure with positive and negative terminals output from both sides, this embodiment can control the length of the wiring between one terminal and other electrical components, thereby reducing the line resistance. This improves the current collection capacity of the battery cell 003.

[0348] In some embodiments, please refer to Figure 14 The thickness of the welding plate 116 is H1, and the thickness of the first current collector 110 is H2, where H2 = bH1, satisfying 0.5 ≤ b ≤ 1.2. Specifically, if the thickness of the welding plate 116 is too large, the welding difficulty increases. If the thickness of the welding plate 116 is too small, the strength of the cover plate body 108 is insufficient, making it prone to deformation under stress. If the thickness of the first current collector 110 is too small, its own strength is insufficient, making it prone to breakage during use. If the thickness of the first current collector 110 is large, the resistance increases accordingly, and the space occupied by the first current collector 110 also increases. When welding the welding plate 116 and the first current collector 110, it should be noted that when b is less than 0.5, the thickness of the first current collector 110 and the welding plate 116 is too small, resulting in reduced strength and a tendency to breakage during use. When b is greater than 1.2, the thickness of the first current collector 110 and the welding plate 116 is too large, resulting in increased resistance, increased space occupation, and increased welding difficulty. More specifically, in this embodiment, the thickness of the welding plate 116 is 0.2 to 0.7 mm.

[0349] For example, the thickness of the first current collector 110 is 0.5H1, 0.6H1, 0.7H1, 0.8H1, 0.9H1, 1.0H1, or 1.1H1. When the thickness of the welding plate 116 is 0.2mm, the thickness of the first current collector 110 can be 0.1mm, 0.12mm, 0.14mm, 0.16mm, 0.18mm, 0.2mm, 0.22mm, or 0.24mm. When the thickness of the welding plate 116 is 0.5mm, the thickness of the first current collector 110 can be 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, or 0.6mm. When the thickness of the welding plate 116 is 0.7mm, the thickness of the first current collector 110 can be 0.35mm, 0.42mm, 0.49mm, 0.56mm, 0.63mm, 0.7mm, 0.77mm, or 0.84mm.

[0350] It should be noted that the method of forming the recess 109 is not limited. In this embodiment, the recess 109 includes a groove. Specifically, the cover plate body 108 is placed on a stamping machine, and a groove is stamped into the cover plate body 108 by stamping. During the stamping process, due to the stamping pressure, the thickness of the bottom of the groove (i.e., the bottom plate 112) is less than the original thickness of the cover plate body 108. It should be noted that the groove includes a bottom plate 112 and a side plate 113. The welding plate 116 can be either the bottom plate 112 or the side plate 113, depending on the actual situation. Considering the ease of welding and the stability of the structure, the welding plate 116 is preferably the bottom plate 112.

[0351] In some embodiments, please refer to Figure 14 The thickness of the welding plate 116 is H1, and the thickness of the area of ​​the cover plate body 108 without the recess 109 is H, where H1 = aH, satisfying: 0.5 ≤ a ≤ 0.7. It should be noted that when a is less than 0.5, the thickness of the welding plate 116 is relatively thin, and the cover plate body 108 is prone to breakage at the recess 109. When a is greater than 0.7, the thickness of the welding plate 116 is relatively thick, increasing the difficulty of welding. In this embodiment, the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4–1 mm. Based on the above relationship, the thickness of the welding plate 116 can be calculated to be 0.2–0.7 mm.

[0352] For example, the thickness of the area of ​​the cover plate body 108 where the recess 109 is not provided can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, or 1mm.

[0353] For example, the thickness of the welding plate 116 is 0.5H, 0.52H, 0.54H, 0.55H, 0.56H, 0.58H, 0.6H, 0.62H, 0.64H, 0.65H, 0.66H, 0.68H, or 0.7H. Specifically, when the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4mm, the thickness of the welding plate 116 can be 0.2mm, 0.208mm, 0.216mm, 0.22mm, 0.224mm, 0.232mm, 0.24mm, 0.248mm, 0.256mm, 0.26mm, 0.264mm, 0.272mm, or 0.28mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.6 mm, the thickness of the welding plate 116 is 0.3 mm, 0.312 mm, 0.324 mm, 0.33 mm, 0.336 mm, 0.348 mm, 0.36 mm, 0.372 mm, 0.384 mm, 0.39 mm, 0.396 mm, 0.408 mm, or 0.42 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 1 mm, the thickness of the welding plate 116 is 0.5 mm, 0.52 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.58 mm, 0.6 mm, 0.62 mm, 0.64 mm, 0.65 mm, 0.66 mm, 0.68 mm, or 0.7 mm.

[0354] In some embodiments, the cover plate body 108 has a base plate 112 for defining the bottom of the recess, and a welding plate 116 is disposed on the base plate 112.

[0355] It is understandable that, compared to setting the welding plate 116 on the recessed peripheral wall, setting the welding plate 116 on the base plate 112 can make the welding plate 116 have a higher flatness, thereby improving the ease of operation of welding the welding plate 116 to components such as tabs or collectors, and thus improving the reliability of welding the welding plate 116 to the corresponding components.

[0356] In some embodiments, please refer to Figure 15 The recessed portion 109 also includes a side plate 113 connected to the base plate 112 to form a recess together with the base plate 112. The base plate 112 is electrically connected to the second electrode 152. The base plate 112 is provided with a welding plate 116 for welding connection. It should be noted that the welding plate 116 can be the entire base plate 112, that is, the entire base plate 112 is welded to the first current collector 110. The welding part can be a part of the base plate 112, that is, a part of the base plate 112 is welded to the first current collector 110.

[0357] The thickness of the welding plate 116 is H1, and the thickness of the side plate 113 is H4, where cH4 = H1, satisfying 0.3 ≤ c ≤ 0.6. It should be noted that when c is less than 0.3, the side plate 113 is relatively thin and prone to breakage during use. When c is greater than 0.6, the thickness of the side plate 113 increases, occupying more space. When the thickness of the welding plate 116 is 0.2mm, the thickness of the side plate 113 can be 0.67mm, 0.571mm, 0.5mm, 0.44mm, 0.4mm, 0.364mm, or 0.34mm. When the thickness of the welding plate 116 is 0.5mm, the thickness of the side plate 113 can be 1.67mm, 1.43mm, 1.25mm, 1.11mm, 1mm, 0.91mm, or 0.84mm. When the thickness of the welding plate 116 is 0.7mm, the thickness of the side plate 113 can be 2.34mm, 2mm, 1.75mm, 1.56mm, 1.4mm, 1.273mm, or 1.167mm.

[0358] In some embodiments, please refer to Figure 15 The recess 109 includes a first bent connecting portion 117 and a second bent connecting portion 118. The first bent connecting portion 117 connects the side plate 113 and the bottom plate 112, and the second bent connecting portion 118 connects the side plate 113 and the area of ​​the cover plate body 108 where the recess 109 is not provided. It should be noted that in the above embodiment, H1 refers to the dimension where the thickness of the welding plate 116 is uniform, excluding the dimension at the bend. Similarly, H4 also refers to the dimension where the thickness of the side plate 113 is uniform, excluding the dimension at the bend. It should be noted that the purpose of providing the first bent connecting portion 117 and the second bent connecting portion 118 is to disperse the force on the recess 109, avoid force concentration, and improve the deformation resistance of the cover plate body 108.

[0359] Please refer to Figure 14 and Figure 15The thickness of the area of ​​the cover plate body 108 without the recessed portion 109 is H, and the radius of curvature of the first bent connecting portion 117 is R1, where R1 = mH, satisfying: 0.8 ≤ m ≤ 2. It should be noted that when m is less than 0.8, the radius of curvature of the first bend is small, failing to achieve the effect of dispersing force. When m is greater than 2, the radius of curvature of the first bent connecting portion 117 is large, leading to an increase in the overall size of the cover plate body 108 and a larger space occupation. Specifically, the radius of curvature of the first bent connecting portion 117 can be 0.8H, 0.82H, 0.84H, 0.85H, 0.88H, 0.9H, 0.92H, 0.94H, 0.95H, 0.96H, 1H, 1.2H, 1.4H, 1.5H, 1.6H, 1.8H, or 2H. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4mm, the radius of curvature of the first bending connection 117 is 0.32mm, 0.328mm, 0.336mm, 0.34mm, 0.352mm, 0.36mm, 0.368mm, 0.376mm, 0.38mm, 0.384mm, 0.4mm, 0.48mm, 0.56mm, 0.6mm, 0.64mm, 0.72mm, and 0.8mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.6mm, the radius of curvature of the first bending connection 117 is 0.48mm, 0.492mm, 0.504mm, 0.51mm, 0.528mm, 0.54mm, 0.552mm, 0.564mm, 0.57mm, 0.576mm, 0.588mm, 0.6mm, 0.66mm, 0.72mm, 0.84mm, 0.9mm, 0.96mm, 1.08mm, and 1.2mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 1mm, the radius of curvature of the first bending connection 117 is 0.8mm, 0.82mm, 0.84mm, 0.85mm, 0.88mm, 0.9mm, 0.92mm, 0.94mm, 0.95mm, 0.96mm, 1mm, 1.2mm, 1.4mm, 1.5mm, 1.6mm, 1.8mm, or 2mm.

[0360] Please see Figure 14 and Figure 15The radius of curvature of the second bent connecting portion 118 is R2, where R2 = nH, satisfying: 0.1 ≤ n ≤ 1. Specifically, the radius of curvature of the second bent connecting portion 118 is 0.1H, 0.2H, 0.3H, 0.4H, 0.5H, 0.6H, 0.7H, 0.8H, 0.9H, and 1H. When the thickness of the area of ​​the cover plate body 108 without the recessed portion 109 is 0.4mm, the radius of curvature of the second bent connecting portion 118 is 0.04mm, 0.08mm, 0.12mm, 0.16mm, 0.2mm, 0.24mm, 0.28mm, 0.32mm, 0.36mm, and 0.4mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.6 mm, the radius of curvature of the second bending connection 118 is 0.06 mm, 0.12 mm, 0.18 mm, 0.24 mm, 0.3 mm, 0.36 mm, 0.42 mm, 0.48 mm, 0.56 mm, and 0.6 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 1 mm, the radius of curvature of the second bending connection 118 is 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.

[0361] In some embodiments, R1 = pR2, satisfying: 0.15 ≤ p ≤ 0.5. Specifically, for example, when the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4 mm, the radius of curvature of the first bent connecting portion 117 is 0.32 mm, and the radius of curvature of the second bent connecting portion 118 is 0.16 mm, then p is 0.5, which meets the requirements of the above formula.

[0362] In some embodiments, the recess 109 includes a first bent connection 117, which connects the side plate 113 and the bottom plate 112. The thickness of the first bent connection 117 gradually decreases along the direction from the side plate 113 to the bottom plate 112. This arrangement makes the connection between the side plate 113 and the area of ​​the cover body 108 where the recess 109 is not located smoother.

[0363] In some embodiments, please refer to Figure 14The thickness of the area of ​​the cover plate body 108 without the recess 109 is H. The width of the recess 109 is L1, where L1 = dH, satisfying: 2.5 ≤ d ≤ 5. It should be noted that the width of the recess 109 here refers to the distance between the two side plates 113 in the cross-section of the recess 109 (i.e., excluding the dimension of the bend). When d is less than 2.5, the overall width of the recess 109 is relatively small, the width of the welding plate 116 is correspondingly reduced, the welding area between the welding plate 116 and the first current collector 110 is reduced, and the welding strength is reduced. When d is greater than 5, the overall width of the recess 109 increases, and the space occupied increases. Specifically, the width of the recess 109 can be 2.5H, 2.6H, 2.8H, 3H, 3.2H, 3.5H, 3.8H, 4H, 4.2H, 4.5H, 4.8H, or 5H. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4 mm, the width of the recess 109 can be 1 mm, 1.04 mm, 1.12 mm, 1.2 mm, 1.28 mm, 1.4 mm, 1.52 mm, 1.6 mm, 1.68 mm, 1.8 mm, 1.92 mm, or 2 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.6 mm, the width of the recess 109 can be 1.5 mm, 1.56 mm, 1.68 mm, 1.8 mm, 1.92 mm, 2.1 mm, 2.28 mm, 2.4 mm, 2.52 mm, 2.7 mm, 2.88 mm, or 3 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 1mm, the width of the recess 109 can be 2.5mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, or 5mm.

[0364] Additionally, please see Figure 14The depth of the recess 109 is L2, where L2 = eH, satisfying 1.5 ≤ e ≤ 3.5. It should be noted that when e is less than 1.5, the depth of the recess 109 is too shallow, resulting in weak resistance to deformation. When the internal air pressure of the battery cell 003 increases, the cover plate body 108 is prone to detaching from the first current collector 110. When e is greater than 3.5, the depth of the recess 109 is too deep, leading to an increase in the overall size of the battery cell 003 and increased space occupation. Specifically, the depth of the recess 109 can be 1.5H, 1.8H, 2H, 2.2H, 2.5H, 2.8H, 3H, 3.1H, 3.2H, or 3.5H. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.4 mm, the depth of the recess 109 can be 0.6 mm, 0.72 mm, 0.8 mm, 0.88 mm, 1 mm, 1.12 mm, 1.2 mm, 1.24 mm, 1.28 mm, or 1.4 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 0.6 mm, the depth of the recess 109 can be 0.9 mm, 1.08 mm, 1.2 mm, 1.32 mm, 1.5 mm, 1.68 mm, 1.8 mm, 1.86 mm, 1.92 mm, or 2.1 mm. When the thickness of the area of ​​the cover plate body 108 without the recess 109 is 1mm, the depth of the recess 109 can be 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.1mm, 3.2mm, or 3.5mm.

[0365] In one embodiment, please refer to Figure 13 In order to facilitate the welding of the welding plate 116 and the first current collector 110, the recess 109 protrudes toward the receiving cavity 311, and at the same time, it can shorten the distance between the cover plate body 108 and the core 001, further preventing the second pole piece 152 from detaching from the cover plate body 108.

[0366] Furthermore, by making the recess 109 protrude toward the receiving cavity 311, the pressure-bearing area of ​​the cover body 108 is increased, so that when the cover body 108 is under pressure, the recess 109 can share part of the pressure on the cover body 108. In this way, the deformation resistance of the cover body 108 can be improved, and the cover body 108 can be prevented from deforming under stress.

[0367] In some embodiments, please refer to Figure 13 and Figure 16The diameter of the circle containing the outer contour of the orthographic projection of the housing 031 on the horizontal plane is D1, and the diameter of the circle containing the center line of the orthographic projection of the recess 109 on the horizontal plane is D2, where D2 = fD1, satisfying: 0.5 ≤ f ≤ 0.8. It should be noted that when f is less than 0.5, the recess 109 is closer to the electrode assembly 107 (i.e., its overall position is slightly inward), which will cause the volume of the second current collector 111a to decrease accordingly, and the current collection capacity of the cell 003 to decrease. When f is greater than 0.8, the recess 109 is closer to the side wall of the housing 031 (i.e., its overall position is slightly outward). Since the recess 109 is welded to the first current collector 110, the volume of the first current collector 110 will be correspondingly smaller, and the current collection capacity of the cell 003 will also decrease. Specifically, in this embodiment, the diameter of the circle containing the outer contour of the orthographic projection of the housing 031 on the horizontal plane is 24–60 mm. The diameter of the circle containing the center line of the orthographic projection of the recess 109 on the horizontal plane is 0.5D1, 0.55D1, 0.6D1, 0.65D1, 0.7D1, 0.75D1, or 0.8D1. When D1 is 24mm, D2 can be 12mm, 13.2mm, 14.4mm, 15.6mm, 16.8mm, 18mm, or 19.2mm. When D1 is 40mm, D2 can be 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, or 32mm. When D1 is 60mm, D2 can be 30mm, 33mm, 36mm, 39mm, 42mm, 45mm, or 48mm.

[0368] It should be noted that the shape of the cross-section of the recess 109 is not limited, as long as it can protrude into the receiving cavity 311. For example, the shape of the cross-section of the recess 109 can be U-shaped, V-shaped, or W-shaped.

[0369] In one embodiment, please refer to Figure 15 To prevent short circuits inside the battery cell 003, a first insulating member 117a is also included. The first insulating member 117a is disposed between the first current collector 110 and the second current collector 111a. The first insulating member 117a is used to isolate the first current collector 110 and the second current collector 111a, preventing them from contacting each other. At the same time, the first insulating member 117a is disposed below the cover plate body 108, which can support the cover plate body 108.

[0370] In related technologies, a battery cell includes a cover assembly, a housing, and a core disposed within the housing. The cover assembly includes a cover body and an electrode assembly. The cover body covers and seals the housing. The electrode assembly passes through the cover body. During operation, the battery cell generates heat, causing its temperature to rise. As the cell temperature rises, accompanied by the chemical reactions during charging and discharging, the electrolyte inside the cell produces gas. When there is too much gas inside the cell and it cannot be properly released, the internal pressure of the cell increases. Excessive pressure pressing against the cover body can cause it to deform and reduce the connection strength between related components. As the internal pressure of the cell continues to increase, the connection between the cover body and the housing may rupture or even explode. If the power is not disconnected inside the cell at this point, the cell is prone to explosion, leading to further thermal runaway.

[0371] Therefore, embodiments of this application also provide a battery cell 003, such as... Figures 17-24 As shown in the figure. The battery cell 003 provided in this application has a simple structure. When the internal air pressure of the battery cell 003 is too high, the cover plate body will break, thereby avoiding the occurrence of explosion or thermal runaway. The battery cell 003 will be described in detail below with reference to the accompanying drawings.

[0372] It is understandable that under normal operating conditions, as the chemical reaction during charging and discharging occurs, gas will be generated inside cell 003. When the internal pressure of cell 003 is lower than the maximum normal operating pressure, for example, 1.2 MPa, cell 003 can operate normally. Generally, in the period before cell 003 triggers thermal runaway, the internal temperature of cell 003 continuously rises, resulting in the continuous generation of a large amount of gas. At this time, the pressure inside cell 003 increases. If the internal pressure exceeds the maximum normal operating pressure and is not released in time, cell 003 may explode or experience thermal runaway.

[0373] Based on this, in one embodiment, the cover plate body 108 includes a first cover plate portion 102 and a second cover plate portion 105. The first cover plate portion 102 is provided with a first hole 103 and an explosion-proof groove 104. The pole post assembly 107 passes through the first hole 103, and the explosion-proof groove 104 is provided on the outside of the first hole 103. The second cover plate portion 105 is connected between the outer periphery of the first cover plate portion 102 and the housing 031. A recessed portion 109 is provided in the second cover plate portion 105 and adjacent to the explosion-proof groove 104.

[0374] It should be noted that the first cover plate portion 102 and the second cover plate portion 105 are integrally formed. In this embodiment, the second cover plate portion 105 can be welded to the housing 031. The cover plate body 108 has a disc-shaped structure. In some embodiments, the cover plate body 108 can be made of steel, such as SPCC material, stainless steel materials SUS410, SUS306, SUS316, SUS430, SUS444, etc. When SPCC material is used, nickel can be plated on both sides of the cover plate body 108, and the thickness of the plating layer is 0.3μm to 8μm. The plating thickness on both sides of the cover plate body 108 can be the same or different. In other embodiments, the cover plate body 108 can be made of aluminum or copper. Aluminum and copper have lower resistance, which can reduce the resistance of the battery cell 003.

[0375] The first current collector 110 is an annular component, and the second current collector 111a is a circular component. The second current collector 111a is located inside the annulus of the first current collector 110, and the first current collector 110 and the second current collector 111a do not contact each other. It should be noted that the centers of the first current collector 110 and the second current collector 111a may or may not coincide, depending on the actual situation and the actual layout of the structure within the battery cell 003.

[0376] In the technical solution of this invention, a recessed portion 109 is provided on the second cover plate portion 105. The recessed portion 109 can enhance the deformation resistance of the second cover plate portion 105, thereby ensuring the connection strength between the second cover plate portion 105 and the housing 031. This effectively solves the problem in related technologies where increased internal pressure of the battery cell 003 presses against the cover plate assembly, causing deformation of the cover plate assembly, reducing the connection strength between the cover plate assembly and the housing 031, and even leading to the cover plate assembly and the housing 031 exploding at the connection point.

[0377] Meanwhile, the first cover plate 102 is provided with explosion-proof grooves 104. When the gas pressure inside the cell 003 increases, the cover plate body 108 breaks at the explosion-proof grooves 104, releasing the gas inside the cell 003 and achieving the purpose of depressurization. This can prevent the second cover plate 105 from exploding at the shell 031, and thus effectively prevent the cell 003 from becoming irritable or thermally runaway.

[0378] It should be noted that in the above embodiments, the explosion-proof notch 104 is integrally disposed on the first cover plate portion 102 of the cover plate body 108. In some other embodiments, the battery cell 003 also includes an explosion-proof sheet separately disposed from the first cover plate portion 102, and the explosion-proof notch 104 may also be disposed on the explosion-proof sheet. The specific structure and position of the explosion-proof sheet can refer to conventional settings in the art, and will not be described in detail here. The specific selection can be made according to the actual situation or actual needs.

[0379] In some embodiments, please refer to 1 and Figure 21 The diameter of the circle containing the outer contour of the housing 031 projected along its axial direction is D1, and the diameter of the circle containing the center line of the orthographic projection of the explosion-proof notch 104 on the horizontal plane is D3, where D3 = a'D1, satisfying: 0.4 ≤ a' ≤ 0.75. Specifically, the explosion-proof notch 104 is provided on the first cover plate portion 102, and the diameter of the explosion-proof notch 104 should not be too large or too small. When a' is less than 0.4, the diameter of the explosion-proof notch 104 is too small, causing the explosion-proof notch 104 to shift towards the direction of the first hole 103. A first insulating member 117a is provided between the cover plate body 108 and the pole post assembly 107. When the diameter of the explosion-proof notch 104 is too small, the position of the explosion-proof notch 104 will coincide with the position of the first insulating member 117a, and the first insulating member 117a will protect the explosion-proof notch 104, preventing the explosion-proof notch 104 from breaking. When a' is greater than 0.75, the explosion-proof notch 104 shifts towards the recess 109. The recess 109 provides some protection for the explosion-proof notch 104, requiring greater pressure to break it. This makes the battery cell 003 prone to thermal runaway. In some embodiments, the diameter of the circle containing the center line of the orthographic projection of the explosion-proof notch 104 on the horizontal plane can be 0.4D1, 0.45D1, 0.5D1, 0.55D1, 0.6D1, 0.65D1, 0.7D1, 0.75D1, or other unlisted values.

[0380] Additionally, the diameter of the circle containing the center line of the orthographic projection of the explosion-proof notch 104 on the horizontal plane is 18–24 mm. When D3 is 18 mm, D1 can be 45 mm, 40 mm, 36 mm, 32.73 mm, 30 mm, 27.69 mm, 25.71 mm, or 24 mm. When D3 is 21 mm, D1 can be 52.5 mm, 46.67 mm, 42 mm, 38.18 mm, 35 mm, 32.31 mm, 30 mm, 28 mm, or other unlisted values. When D3 is 24 mm, D1 can be 60 mm, 53.33 mm, 48 mm, 43.64 mm, 40 mm, 36.92 mm, 34.29 mm, 32 mm, or other unlisted values.

[0381] Please continue reading. Figure 17 and Figure 21The diameter of the circle containing the center line of the orthographic projection of the recess 109 on the horizontal plane is D2, where D2 = fD1, satisfying: 0.5 ≤ f ≤ 0.8. It should be noted that when f is less than 0.5, the recess 109 shifts towards the explosion-proof notch 104, meaning the distance between the recess 109 and the explosion-proof notch 104 shortens. The recess 109 provides some protection to the explosion-proof notch 104. When the internal pressure of the battery cell 003 is too high, the explosion-proof notch 104 requires a greater force to break, increasing the risk of battery cell 003 explosion or thermal runaway. When f is greater than 0.8, the recess 109 shifts away from the explosion-proof notch 104, increasing the longitudinal dimension of the second cover plate portion 105 and the longitudinal dimension of the cover plate body 108, thus increasing the space occupied. In some embodiments, the diameter of the circle containing the center line of the orthographic projection of the recess 109 on the horizontal plane is 0.5D1, 0.55D1, 0.58D1, 0.6D1, 0.62D1, 0.65D1, 0.68D1, 0.7D1, 0.75D1, 0.77D1, 0.8D1, or other unlisted values.

[0382] For example, when D1 is 24mm, D2 can be 12mm, 13.2mm, 13.92mm, 14.4mm, 14.88mm, 15.6mm, 16.32mm, 16.8mm, 18mm, 18.48mm, 19.2mm, or other unlisted values. When D1 is 40mm, D2 can be 20mm, 22mm, 23.2mm, 24mm, 24.8mm, 26mm, 27.2mm, 28mm, 30mm, 30.8mm, 32mm, or other unlisted values. When D1 is 60mm, D2 can be 30mm, 33mm, 34.8mm, 36mm, 37.2mm, 39mm, 40.8mm, 42mm, 45mm, 46.2mm, 48mm or other unlisted values.

[0383] In some embodiments, please refer to Figure 1 The thickness of the cover plate body 108 is H, where D2-D3=2c'H, satisfying c'>3. It should be noted that while the diameters of the circles containing the center lines of the orthographic projections of the cover plate body 108, the recessed portion 109, and the explosion-proof notch 104 on the horizontal plane must satisfy their respective proportional relationships, D2-D3=2c'H must also be satisfied. This arrangement allows for a reasonable layout of the explosion-proof notch 104 and the recessed portion 109, improving the space utilization of the battery cell 003.

[0384] For example, the thickness of the cover body 108 is 0.4 to 1 mm. More specifically, the thickness of the cover body 108 can be 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, or other unlisted values.

[0385] Specifically, the specific structural type of the recess 109 is not limited, as long as it can improve the deformation resistance of the second cover plate 105, causing the cover plate body 108 to break at the groove when the internal air pressure of the battery cell 003 increases. In some embodiments, the recess 109 is formed by bending. In other embodiments, the recess 109 is formed by stamping.

[0386] Please refer to Figure 21 and Figure 23 The recessed portion 109 is electrically connected to the second electrode tab 012, making the cover plate body 108 serve as one output electrode. The electrode post assembly 107 is electrically connected to the second electrode plate 152, making the electrode post assembly serve as the other output electrode, thereby achieving same-side output. Simultaneously, the recessed portion 109 can disperse the pressure on the cover plate body 108, improving its resistance to deformation. When the internal air pressure of the battery cell 003 increases, the recessed portion 109 can prevent the cover plate body 108 from bearing greater forces, thus extending the service life of the battery cell 003.

[0387] It is understood that the direction of the recess 109 is not limited, as long as it can improve the deformation resistance of the cover body 108. In some embodiments, the recess 109 is configured to protrude from one side of the second cover portion 105 away from the receiving cavity 311.

[0388] In another embodiment, the recess 109 is configured such that one side of the second cover plate portion 105 is recessed into the receiving cavity 311. It should be noted that the recessed arrangement is better than the protruding arrangement. On the one hand, the recess into the receiving cavity 311 can control the volume of the battery cell 003 and improve the utilization rate of the internal space of the battery cell 003. On the other hand, the recess into the receiving cavity 311 can shorten the current collection path between the second cover plate portion 105 and the core 001, thereby improving the current collection capacity.

[0389] It should be noted that the connection method between the recess 109 and the second electrode tab 012 is not limited, nor is the connection method between the electrode post assembly 107 and the second electrode plate 302. For example, in one embodiment, to control the number of components, the recess 109 is directly connected to the second electrode tab 012, and the electrode post assembly 107 is directly connected to the first electrode tab 011. In another embodiment, please refer to... Figure 1To ensure connection strength and improve the stability of the battery cell 003, the winding core 001 includes a first current collector 110 and a second current collector 111a. The first current collector 110 is disposed between the second tab 012 and the second cover plate portion 105, and the first current collector 110 is electrically connected to the second tab 012 and the recessed portion 109. At the same time, the second current collector 111a is disposed between the first tab 011 and the terminal assembly 107, and the second current collector 111a is electrically connected to both the first tab 011 and the terminal assembly 107.

[0390] Furthermore, in order to ensure connection strength, the first current collector 110 is welded to the second tab 012 and the second cover plate portion 105 at the recess 109, and the second current collector 111a is welded to the first tab 011 and the pole assembly 107.

[0391] In one embodiment, please refer to Figure 21 and Figure 22The thickness of the area of ​​the second cover plate portion 105 without the recessed portion 109 is H, the thickness of the area of ​​the first cover plate portion 102 without the explosion-proof notch 104 is H6, and the notch depth of the explosion-proof notch 104 is H32, where (H6-H32)=pH1, satisfying: 0.14≤p≤0.6. Here, H6-H32 refers to the thickness of the first cover plate portion 102 at the explosion-proof notch 104. For ease of description, the thickness of the first cover plate portion 102 at the explosion-proof notch 104 is H60 (i.e., H60=H6-H32), that is, H60=pH32. It should be noted that when p is less than 0.14, the thickness of the first cover plate 102 at the explosion-proof notch 104 is relatively small, and the structural strength of the first cover plate 102 at the explosion-proof notch 104 is relatively weak. During normal use of the battery cell, the first cover plate 102 at the explosion-proof notch 104 will break, affecting the normal use of the battery cell 003. When p is greater than 0.6, the structural strength of the first 102 at the explosion-proof notch 104 is relatively weak, which will cause the welding plate 116 to disconnect from the first current collector 110 first, causing the battery cell 003 to break without being de-energized, increasing the risk factor. For example, H60 can be 0.14H1, 0.15H1, 0.2H1, 0.22H1, 0.24H1, 0.29H1, 0.3H1, 0.35H1, 0.4H1, 0.42H1, 0.48H1, 0.5H1, 0.55H1, 0.6H1, or other unlisted values. When H1 is 0.5mm, H60 can be 0.07mm, 0.075mm, 0.1mm, 0.11mm, 0.12mm, 0.145mm, 0.15mm, 0.175mm, 0.2mm, 0.21mm, 0.24mm, 0.25mm, 0.275mm, 0.3mm, or other unlisted values. It should be noted that the depth of the explosion-proof groove 104 should not be too shallow. Otherwise, when the internal air pressure of the battery cell 003 increases, the explosion-proof groove 104 will not be able to break, and the welding plate 116 will break off from the first current collector 110 first, causing the battery cell to explode or even thermal runaway. The depth of the explosion-proof groove 104 should not be too deep. Otherwise, the first cover plate 102 may break during normal use.

[0392] In another embodiment, the thickness of the area of ​​the second cover plate portion 105 without the recessed portion 109 is H, the thickness of the area of ​​the first cover plate portion 102 without the explosion-proof notch 104 is H6, and the notch depth of the explosion-proof notch 104 is H32, where (H6-H32)=qH, satisfying: 0.1≤q≤0.3. Here, H6-H32 refers to the thickness of the first cover plate portion 102 at the explosion-proof notch 104. For ease of description, the thickness of the first cover plate portion 102 at the explosion-proof notch 104 is H60 (i.e., H60=H6-H32). The thickness of the area of ​​the first cover plate portion 102 without the explosion-proof notch 104 is the same as the thickness of the area of ​​the second cover plate portion 105 without the recessed portion 109, i.e., H6=H, thus H60=qH6. Specifically, when q is less than 0.1, the thickness of the first cover plate portion 102 at the explosion-proof notch 104 is small, and the structural strength of the first cover plate portion 102 at the explosion-proof notch 104 is weak. During normal use of the battery cell, the first cover plate portion 102 will break at the explosion-proof notch 104, affecting the normal use of the battery cell 003. When q is greater than 0.3, the thickness of the first cover plate portion 102 at the explosion-proof notch 104 is large. When the air pressure inside the battery cell 003 reaches the second air pressure, the first cover plate portion 102 cannot break at the explosion-proof notch 104, increasing the risk factor. For example, H60 can be 0.1H, 0.14H, 0.15H, 0.18H, 0.2H, 0.21H, 0.25H, 0.256H, 0.272H, 0.28H, 0.295H, 0.3H, or other unlisted values. Specifically, when H6 is 1 mm, H60 can be 0.1 mm, 0.14 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.21 mm, 0.25 mm, 0.256 mm, 0.272 mm, 0.28 mm, 0.295 mm, 0.3 mm, or other unlisted values.

[0393] It should be noted that, in the event of thermal runaway, the battery cell 003 provided by this invention first disconnects the power and then depressurizes, thereby improving the safety performance of the battery cell 003. Specifically, the cover plate body 108 has a normal state. In the normal state, the first cover plate part 102 is also provided with a first groove 108b. The first groove 108b has a first bottom wall 109b and a first inner side wall 110b connected to the first bottom wall 109b. An explosion-proof notch 104 is provided on the first bottom wall 109b. The first groove 108b is located above the explosion-proof notch 104. When the internal air pressure of the battery cell 003 increases, the air pressure acts on the cover plate assembly, pushing the cover plate assembly to move away from the core 001. Under the action of the first air pressure, the first groove 108b is flattened (i.e., the first inner side wall 110b of the first groove 108b is flush with the upper end surface of the first cover plate part 102, such as...). Figure 17 or Figure 18As shown in the figure, at this time, the first cover plate 102 has not yet broken, but the pole post assembly 107 is separated from the core 001, thereby achieving power cut-off.

[0394] In some embodiments, please refer to Figure 21 and Figure 22 The thickness of the area of ​​the first cover plate portion 102 without the first groove 108b is H3 (i.e., H3 = H6 = H), and the groove width of the first groove 108b is H40, where H40 = k'H3, satisfying: 2 ≤ k' ≤ 5. For example, H40 can be 2H3, 2.1H3, 2.4H3, 2.5H3, 2.8H3, 3H3, 3.5H3, 3.7H3, 3.8H3, 4.2H3, 4.5H3, 5H3, or other unlisted values. Specifically, when H3 is 1mm, H4 can be 2mm, 2.1mm, 2.4mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 3.7mm, 3.8mm, 4.2mm, 4.5mm, 5mm, or other unlisted values.

[0395] The depth of the first groove 108b is H50, where H50 = m'H3, satisfying 1 ≤ m' ≤ 2. It should be noted that when m' is less than 1, the depth of the first groove 108b is too shallow. When the air pressure inside the battery cell 003 reaches the first air pressure, the explosion-proof notch 104 may break preferentially, causing the battery cell 003 to fail to disconnect power normally. When m' is greater than 2, the depth of the first groove 108b is too deep. When the air pressure inside the battery cell 003 reaches the first air pressure, the terminal assembly 107 and the winding core 001 have not yet broken, causing the battery cell 003 to fail to disconnect power, increasing the risk factor. For example, H50 can be 1H3, 1.1H3, 1.18H3, 1.2H3, 1.22H3, 1.25H3, 1.3H3, 1.44H3, 1.5H3, 1.62H3, 1.72H3, 1.8H3, 1.85H3, 1.9H3, 1.92H3, 1.96H3, 2H3, or other unlisted values. Specifically, when H3 is 1mm, H50 can be 1mm, 1.1mm, 1.18mm, 1.2mm, 1.22mm, 1.25mm, 1.3mm, 1.44mm, 1.5mm, 1.62mm, 1.72mm, 1.8mm, 1.85mm, 1.9mm, 1.92mm, 1.96mm, 2mm, or other unlisted values.

[0396] Furthermore, the thickness of the area of ​​the first bottom wall 109b without the explosion-proof notch 104 is H6, where H6 = n'H3, satisfying 0.5 ≤ n' ≤ 1. It should be noted that when n' is less than 0.5, the thickness of the first bottom wall 109b is small, the structural strength of the first cover plate 102 is weak, and the battery cell 003 will break during normal use. When n' is greater than 1, the thickness of the first bottom wall 109b is large, increasing the space occupied by the cover plate assembly. Simultaneously, since the explosion-proof notch 104 is located on the first bottom wall 109b, the increased thickness of the first bottom wall 109b requires a greater force to break the explosion-proof notch 104, increasing the risk factor. For example, H6 can be 0.5H3, 0.52H3, 0.55H3, 0.6H3, 0.62H3, 0.7H3, 0.8H3, 0.9H3, 0.96H3, 1H3, or other unlisted values. Specifically, when H3 is 1 mm, H6 can be 0.5 mm, 0.52 mm, 0.55 mm, 0.6 mm, 0.62 mm, 0.7 mm, 0.8 mm, 0.9 mm, 0.96 mm, 1 mm, or other unlisted values.

[0397] In one embodiment, to facilitate the disconnection of the electrode assembly 107 and the core 001, the first inner sidewall 110b is inclined relative to the first bottom wall 109b, and the included angle between the first inner sidewall 110b and the first bottom wall 109b is α, where 55°≤α≤135°. Specifically, when α is less than 55°, the first inner sidewall 110b surrounds the explosion-proof notch 104, providing some protection for the notch and preventing it from breaking under the second pressure. Simultaneously, the core 001 and the electrode assembly 107 require greater force to disconnect, increasing the risk. When α is greater than 135°, the first inner sidewall 110b and the first bottom wall are nearly a straight line, increasing the distance between the electrode assembly 107 and the core 001, thus increasing the overall space occupied by the cell 003. In this embodiment, α can be 55°, 60°, 62°, 75°, 78°, 80°, 84°, 90°, 92°, 99°, 0.32°, 110°, 115°, 120°, 125°, 130°, 132°, 135° or other unlisted values.

[0398] It should be noted that the groove of the first groove 108b protrudes toward the receiving cavity 311, and the cover plate body 108 also has an abnormal state. The first cover plate portion 102 of the cover plate body 108 in the abnormal state is flatter than the first cover plate portion 102 of the cover plate body 108 in the normal state.

[0399] Please see Figure 13In this embodiment, the terminal assembly 107 serves as one output terminal, and the cover plate body 108 serves as the other output terminal. The cover plate body 108 and the terminal assembly 107 are located on the same side. To prevent short circuits, the cell 003 also includes a second insulating member 113b. The second insulating member 113b is disposed between the terminal assembly 107 and the first connecting plate 111b, serving as an insulator to prevent the terminal assembly 107 from contacting the cover plate body 108 and causing a short circuit. Further, the first cover plate portion 102 includes a first connecting plate 111b and a second connecting plate 112b connected to the outer periphery of the first connecting plate 111b. Explosion-proof grooves 104 are provided on the second connecting plate 112b, and the second insulating member 113b abuts against the second connecting plate 112b. This arrangement limits and fixes the second insulating member 113b, preventing it from slipping and causing a short circuit inside the cell 003. The first hole 103 is provided on the first connecting plate 111b.

[0400] In one embodiment, the second insulating member 113b includes a first insulating portion 114b and a second insulating portion 115b. A first connecting plate 111b is located between the first insulating portion 114b and the second insulating portion 115b. The first insulating portion 114b and the second insulating portion 115b wrap around the first connecting plate 111b, and the inner peripheral side of the first insulating portion 114b passes through the first hole 103 and connects to the inner peripheral side of the second insulating portion 115b. The purpose of this arrangement is to provide a certain degree of protection for the first connecting plate 111b. When the air pressure inside the battery cell 003 increases, the first connecting plate 111b will not break first, so that the breakage location is at the explosion-proof notch 104 of the second connecting plate 112b. The second insulating portion 115b is located on the side of the first connecting plate 111b closer to the receiving cavity 311. The second connecting plate 112b is sunken towards the receiving cavity 311 to form a sunken structure, and the outer peripheral side of the second insulating portion 115b abuts against the sunken structure.

[0401] In some embodiments, explosion-proof grooves 104 are provided around the first hole 103, which allows the pole assembly 107 and the core 001 to be completely disconnected, so that the cell 003 is in a de-energized state, thereby reducing the probability of thermal runaway.

[0402] In one embodiment, to improve the safety performance of battery cell 003, when the internal pressure of battery cell 003 changes, the power to the battery cell 003 needs to be cut off first, followed by pressure relief. For details, please refer to [link to relevant documentation]. Figure 17 or Figure 18When the air pressure inside the receiving cavity 311 is at the first air pressure, the electrode assembly 107 is disconnected from the winding core 001. At the first air pressure, the cover plate body 108 will not break. The electrode assembly 107 and the winding core 001 disconnect first, and at this time, the battery cell 003 is in a de-energized state. After the battery cell 003 is de-energized, it no longer works, and the temperature of the battery cell 003 will not continue to rise, thereby controlling the internal pressure of the battery cell 003 and improving the safety of the battery cell 003.

[0403] For example, the first pressure is P1, where 1.2 MPa ≤ P1 ≤ 1.8 MPa. More specifically, P1 may be set to 1.2 MPa, 1.25 MPa, 1.26 MPa, 1.28 MPa, 1.31 MPa, 1.33 MPa, 1.4 MPa, 1.43 MPa, 1.48 MPa, 1.5 MPa, 1.55 MPa, 1.58 MPa, 1.62 MPa, 1.66 MPa, 1.77 MPa, 1.79 MPa, 1.8 MPa, or other unlisted values.

[0404] It should be noted that there are multiple ways in which the pole assembly 107 can be disconnected from the core 001, and various forms may occur in actual applications.

[0405] Format 1: Please refer to Figure 17 A second current collector 111a is provided between the terminal assembly 107 and the core 001. The terminal assembly 107 and the second current collector 111a are welded together, and the second current collector 111a is welded together with the second electrode tab. When the pressure inside the cell 003 exceeds 1.2MPa, the gas inside the cell 003 pushes the terminal assembly 107 to move away from the core 001. As the pressure increases, the terminal assembly 107 is disconnected from the second current collector 111a, and the cell 003 is de-energized.

[0406] Format Two: Please refer to Figure 18 A second current collector 111a is provided between the pole assembly 107 and the core 001. The pole assembly 107 is welded to the second current collector 111a, and the second current collector 111a is welded to the second tab. When the pressure inside the cell 003 exceeds 1.2MPa, the gas inside the cell 003 pushes the pole assembly 107 to move away from the core 001. As the pressure increases, the second current collector 111a is disconnected from the second tab, and the cell 003 is de-energized.

[0407] Please see Figure 19When the thermal runaway of cell 003 reaches its final stage, the internal pressure of cell 003 rises to a certain level, requiring the explosion-proof valve to open and release the combustible material inside cell 003 to prevent cell 003 from exploding. In this embodiment, when the internal pressure of cell 003 exceeds 1.8 MPa, the cover plate body 108 breaks at the explosion-proof notch 104, allowing the gas inside cell 003 to escape. Specifically, when the pressure inside the receiving cavity 311 is the second pressure, the cover plate body 108 breaks at the explosion-proof notch 104, where the second pressure is P2, and P2 > 1.8 MPa. More specifically, P2 may be set to 1.82 MPa, 1.85 MPa, 1.91 MPa, 1.98 MPa, 2.1 MPa, 2.21 MPa, 2.24 MPa, 2.28 MPa, 2.4 MPa, 2.45 MPa, 2.55 MPa, or other unlisted values.

[0408] Please see Figure 25 In one embodiment, the first tab 011, the second tab 012, and the third tab 013 are die-cut tabs. Die-cut tabs refer to tabs of the desired shape that are cut into the uncoated area of ​​the current collector using a mold and a cutting tool, such as a laser cutter.

[0409] In this embodiment, by using die-cut tabs, the forming method of the tabs can be made simple and convenient, and the consistency of the tabs can be improved, ensuring that the shape, size and spacing of the tabs meet the design requirements.

[0410] Please see Figure 25 In one embodiment, the die-cut width of the die-cut tab is W0, which satisfies 2mm≤W0≤6mm.

[0411] For example, W0 includes, but is not limited to, 2mm, 2.2mm, 2.5mm, 2.6mm, 3mm, 3.2mm, 3.62mm, 4.15mm, 4.8mm, 5mm, 5.33mm, 5.42mm, 5.62mm, 5.82mm, 5.96mm, 5.99mm, and 6mm.

[0412] Specifically, if the distance from the electrode tip to the electrode body is within 35% of the electrode length, the die-cutting width W is 2–4 mm; if the distance is greater than 35% of the electrode body length, the die-cutting width W is 4–6 mm. Furthermore, the die-cutting width W gradually increases with distance from the electrode tip. This reduces the obstruction to the flattening of the electrode tab at the connection point between the tab and the coating area, thereby improving the ease of flattening and ultimately increasing flattening efficiency.

[0413] In this embodiment, the above limitations can, on the one hand, prevent the electrode from breaking easily due to excessively small die-cut width, thereby ensuring the reliability of the connection between the electrode tab and the coating area; on the other hand, can prevent the resistance to flattening the electrode tab from being too large due to a large die-cut width.

[0414] Please see Figure 25 In one embodiment, the die-cutting angle of the die-cut tab is α0, which satisfies 55°≤α0≤85°.

[0415] It can be understood that the die-cutting angle is the acute angle between the laser cutting trajectory and the length direction of the electrode.

[0416] For example, α0 includes, but is not limited to, 55°, 57.5°, 59°, 60°, 62.5°, 66°, 68°, 70°, 71.3°, 75°, 76.4°, 80°, 81°, 83.3°, 84°, and 85°.

[0417] In this embodiment, the above-mentioned limitations can guide the bending of the electrode tabs during the flattening process, thereby allowing adjacent electrode tabs to overlap, which can reduce the interference between adjacent electrode tabs and improve the flatness of the overlap of the flattened electrode tabs.

[0418] In one embodiment, the die-cutting height of the die-cut tab is H0, which satisfies: 5mm≤H0≤7.5mm.

[0419] For example, H0 includes, but is not limited to, 5mm, 5.2mm, 5.48mm, 5.9mm, 6mm, 6.5mm, 6.7mm, 6.9mm, 7mm, 7.15mm, 7.3mm, 7.46mm, and 7.5mm.

[0420] In this embodiment, the above-mentioned limitations can, on the one hand, prevent the tab from being cut too small, which would make it difficult to form a sufficient welding surface for welding with the current collector after the tab is bent; on the other hand, can prevent the tab from being cut too large, which would occupy too much space inside the cell.

[0421] It's understandable that thermal management has always been a focus for new energy vehicles. As the energy density and power density of new energy vehicle power batteries increase, the heat generated by the batteries also increases, making heat dissipation systems with characteristics such as fast cooling speed and high heat transfer coefficient increasingly important. In related technologies, serpentine tubes are wound around the peripheral side of the battery module cells for cooling. However, the thermal conductivity of the battery cell in the axial direction is much greater than that in the diametrical direction. Therefore, the cooling efficiency of using serpentine tubes to cool the peripheral side of the battery cell is low, and thermal runaway is prone to occur.

[0422] Therefore, embodiments of this application also provide a battery module; please refer to [link / reference]. Figures 26 to 33The battery module provided in the embodiments of this application has high cooling efficiency, high safety, and a low probability of thermal runaway; the battery module will be described in detail below with reference to the relevant accompanying drawings.

[0423] Please see Figure 26 , Figure 27 and Figure 28 The battery module 060 includes a cooling device 061 and multiple battery cells 003. The cooling device 061 includes a first cooling plate 062. Each battery cell 003 includes a housing 031, a core 001, and a third current collector 066. The portion of the housing 031 near the third tab 013 is an end plate 067. The end plate 067 can be integrally formed with the other parts of the housing or can be separate. The core 001 is disposed within the housing 031. The third current collector 066 is located between the end plate 067 and the third tab 013 and is electrically connected to the third tab 013. The third current collector 066 includes a heat-conducting part 666, which is connected to the side of the end plate 067 facing the core 001. The side of the end plate 067 away from the core 001 is connected to the first cooling plate 062.

[0424] Here, the connection between end plate 067, first cooling plate 062, and core 001 is at least thermally coupled. Thermal coupling refers to a connection method in which two objects influence each other through a heat transfer mechanism.

[0425] It is understandable that the axial flow of the winding core 001 along the axial direction of the cell 003 leads to an increase in axial heat generation in the cell 003, resulting in higher axial heat levels. Therefore, a first cooling plate 062 is provided at the bottom of the cell 003 to cool and exchange heat along the axial direction, thereby improving the cooling efficiency of the battery module 060. The cooling method of the first cooling plate 062 includes, but is not limited to, air cooling, liquid cooling, or direct cooling.

[0426] In this embodiment, the third current collector 066 is connected to the housing 031, and a first cooling plate 062 is provided below the multiple battery cells 003. The bottom of the battery cells 003 is cooled by the first cooling plate 062, and the top of the battery cells 003 can dissipate heat by contacting the air. This allows the top and bottom of the battery cells 003 to transfer heat energy simultaneously for heat dissipation, improving the axial heat dissipation capability of the battery module 060. This, in turn, enables better control of the temperature of the battery module 060, making the battery module 060 suitable for fast charging and discharging applications such as high-rate discharge.

[0427] For ease of description, the side of end plate 067 closest to core 001 is the top surface 069, and the side of end plate 067 away from core 001 is the bottom surface 068.

[0428] It should be noted that in some embodiments, the first cooling plate 062 is made of an insulating material. In another embodiment, the first cooling plate 062 has an insulating layer on the side facing the multiple battery cells, and the insulating layer is capable of conducting heat.

[0429] The heat-conducting part 666 transfers the heat from the third collector 066 to the end plate 067, and the end plate 067 then transfers the heat to the first cooling plate 062, which carries away the heat, thereby achieving heat dissipation.

[0430] In one embodiment, the heat-conducting part 666 includes two first side surfaces arranged opposite to each other. One of the first side surfaces faces the end plate 067 and is a first heat-conducting surface 071. The first heat-conducting surface 071 is connected to the end plate 067 and is used to transfer heat to the end plate 067. Further, the end plate 067 includes two second side surfaces arranged opposite to each other. One of the second side surfaces faces the heat-conducting part 666 and the other second side surface faces the first cooling plate 062. The second side surface facing the first cooling plate 062 is a second heat-conducting surface 072 and is connected to the first cooling plate 062. Specifically, the heat generated by the core 001 and the third current collector 066 is transferred to the heat-conducting part 666. The heat-conducting part 666 transfers heat to the end plate 067 through the first heat-conducting surface 071, and the end plate 067 transfers heat to the first cooling plate 062 through the second heat-conducting surface 072, thereby realizing heat transfer.

[0431] It should be noted that both ends of the core 001 of the battery cell 003 provided in this embodiment have current-collecting capabilities. In this embodiment, the third current collector 066 is a negative current collector, located at the end of the core 001 near the first cooling plate 062. The battery cell 003 also includes a first current collector 110, a second current collector 111a, and a fourth current collector. The first current collector 110 and the second current collector 111a are located at the end of the core 001 away from the first cooling plate 062. The fourth current collector and the third current collector 066 are located at the end of the core 001 near the first cooling plate 062. The arrangement of these four current collectors is not limited, as long as current transmission can be achieved. Specifically, in this embodiment, taking the end of the battery cell 003 near the first cooling plate 062 as an example, the fourth current collector is arranged around the third current collector 066, and the third current collector 066 is connected to the third tab 013, and the fourth current collector is connected to the fourth tab 014.

[0432] Specifically, please refer to Figure 30 and Figure 31The area of ​​the first heat-conducting surface 071 is S1, and the area of ​​the second heat-conducting surface 072 is S2, where S1:S2 = (0.05~0.25):1. In this embodiment, the end of the battery cell 003 near the first cooling plate 062 is provided with both a third current collector 066 and a fourth current collector. The area of ​​the third current collector 066 should not be too large or too small. If the area of ​​the third current collector 066 is too large, it will result in the area of ​​the fourth current collector being too small, reducing the current collection capacity and making the fourth current collector prone to burning. If the area of ​​the third current collector 066 is too small, the current collection capacity will also be reduced, and the third current collector 066 will also be prone to burning.

[0433] It should be noted that the connection method between the third current collector 066 and the end plate 067 is not limited. In one embodiment, the third current collector 066 abuts against the end plate 067; in another embodiment, the third current collector 066 is welded to the end plate 067. It should also be noted that the axial thermal conductivity of the battery cell 003 is more than 200 times that of the radial thermal conductivity. In this embodiment, by connecting the third current collector 066 to the end plate 067, the negative electrode of the battery cell 003 is directly connected to the casing 031. The end plate 067 of the battery cell 003 acts as a heat-conducting component. A first cooling plate 062 is provided at the axial ends of multiple battery cells 003 to achieve axial heat dissipation of the battery cells 003. This better controls the temperature of the battery module 060, enabling the battery and module to perform fast charging or fast discharging operations such as high-rate discharge without thermal runaway.

[0434] In some embodiments, the welding area between the third current collector 066 and the end plate 067 is S3, where S3:S2 = (0.01~0.05):1. It should be noted that when S3 / S2 is less than 0.01, the welding area between the third current collector 066 and the end plate 067 is small, resulting in insufficient adhesion between them and a reduced thermal conductivity of the battery cell 003. When S3 / S2 is greater than 0.05, the welding area between the third current collector 066 and the end plate 067 increases, increasing the difficulty of welding and potentially affecting the second current collector during the welding process.

[0435] In some embodiments, please refer to Figure 28 and Figure 29The end plate 067 has a second groove 073 with an opening facing the core 001, and a heat-conducting part 666 is disposed in the second groove 073. In the actual installation process, the heat-conducting part 666 is first snapped into the second groove 073, and then the heat-conducting part 666 is welded to the bottom of the second groove 073. It should be noted that in this embodiment, the second groove 073 has two functions: one is to pre-fix the heat-conducting part 666 to the second groove 073 to facilitate welding; the other is that the purpose of setting the second groove 073 is to reduce the thickness of the end plate 067 of the shell 031, so that heat can be transferred to the first cooling plate 062 as soon as possible to achieve heat exchange.

[0436] The specific shape of the second groove 073 is not limited, as long as it can achieve pre-fixation.

[0437] It is understood that the second groove 073 has a second bottom wall 074 and a second inner sidewall 075, the second inner sidewall 075 being disposed perpendicular to the second bottom wall 074. In another embodiment, please refer to 31 and Figure 32 The second groove 073 has a second bottom wall 074 and a second inner side wall 075 connected to the second bottom wall 074. The heat-conducting part 666 protrudes into the second groove 073 and is connected to the second bottom wall 074. The second inner side wall 075 is inclined relative to the second bottom wall 074. Specifically, the second inner side wall 075 has a first end close to the heat-conducting part 666 and a second end away from the heat-conducting part 666. In the direction from the first end to the second end, the second inner side wall 075 is inclined towards the second bottom wall 074. The purpose of this arrangement is to facilitate the welding of the heat-conducting part 666 to the second bottom wall 074.

[0438] In some embodiments, the included angle between the second inner sidewall 075 and the second bottom wall 074 is γ, where 105°≤γ≤135°. When the included angle between the second inner sidewall 075 and the end plate 067 is greater than 135°, the size of the second groove 073 is too large, resulting in the overall thickness of the end plate 067 of the housing 031 being too small, and the strength of the end plate 067 being insufficient. When the included angle between the second inner sidewall 075 and the end plate 067 is less than 0.01°, the tilt angle of the second inner sidewall 075 is insufficient, increasing the difficulty of welding. Specifically, the included angle between the second inner sidewall 075 and the second bottom wall 074 can be 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119°, 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, or 135°. As an optional embodiment, the included angle between the second inner sidewall 075 and the second bottom wall 074 is 120°. This ensures the strength of the housing 031 while facilitating the welding of the heat-conducting part 666 to the second bottom wall 074.

[0439] In some embodiments, taking the end of the battery cell 003 near the first cooling plate 062 as an example, the fourth current collector is arranged around the third current collector 066, and the third current collector 066 is connected to the third tab 013. Since the third current collector 066 is connected to the central region of the core 001, correspondingly, in order to facilitate the welding of the third current collector 066 to the housing 031, the second groove 073 is correspondingly arranged in the central region of the end plate 067. Specifically, please refer to Figure 31 and Figure 32 The end plate 067 has a first part and a second part surrounding the first part, and a second groove 073 is formed on the first part; the vertical distance between the second bottom wall 074 of the second groove 073 and the bottom surface 068 of the end plate 067 is W1, and the thickness of the second part is W2, where W1:W2 = (0.3~0.6):1. It should be noted that the wall thickness of the second bottom wall 074 of the second groove 073 should not be too thick or too thin. When the thickness of the second bottom wall 074 of the second groove 073 is too large, the thermal conductivity of the housing 031 is reduced, heat dissipation cannot be carried out in time, and the third current collector 066 is prone to ablation; when the thickness of the second bottom wall 074 of the second groove 073 is relatively thin, the end plate 067 of the housing 031 is locally thin, the stress is uneven, and the strength is low, making it easy to be damaged, resulting in a lower service life of the battery module 060.

[0440] In some embodiments, please refer to Figure 32The vertical distance between the second bottom wall 074 of the second groove 073 and the bottom surface 068 of the end plate 067 is W1, and the thickness of the heat-conducting part 666 is W3, where W3:W1 = (0.2~1.2):1. It should be noted that the wall thickness of the heat-conducting part 666 should not be too thick or too thin. In this embodiment, the third current collector 066 is connected to the housing 031, so the housing 031 serves as the output end of the battery cell 003. Therefore, when the thickness of the heat-conducting part 666 is too large, it is easy for incomplete soldering to occur during the welding process, leading to leakage, and the resistance of the battery cell 003 increases accordingly, resulting in greater energy loss during current transmission. When the thickness of the heat-conducting part 666 is too thin, when the temperature of the battery cell is too high, it is easy to burn out, causing damage to the battery module 060 and reducing its service life.

[0441] In some embodiments, the battery cell 003 further includes a first current collector 110, and the two ends of the wound core 001 are provided with tabs of the same polarity. The first current collector 110 is connected to the tabs away from the first cooling plate 062, and a third current collector 066 is welded to the tabs close to the first cooling plate 062. The tabs can be welded tabs, full tabs, or die-cut tabs.

[0442] In one embodiment, please refer to Figure 29 and Figure 31 The third collector 066 further includes a collector section 076 and a connecting section 077. The collector section 076 is connected to the core 001, and the connecting section 077 is connected between the collector section 076 and the heat-conducting section 666. The connecting section 077 is inclined relative to the heat-conducting section 666. In this embodiment, the collector section 076 is connected to the core 001, and the connecting section 077 is connected between the collector section 076 and the heat-conducting section 666. The core 001 transfers heat to the collector section 076, and the collector section 076 transfers heat to the heat-conducting section 666 through the connecting section 077. The heat-conducting section 666 then transfers heat to the end plate 067 of the housing 031, and the end plate 067 of the housing 031 then transfers heat to the first cooling plate 062, completing the heat exchange. More specifically, the end of the connecting part 077 connected to the current collector 076 is the third end, and the end of the connecting part 077 connected to the heat-conducting part 666 is the fourth end. In the direction from the third end to the fourth end, the connecting part 077 is inclined towards the heat-conducting part 666. This arrangement allows the connecting part 077 to cooperate with the second inner wall 075 of the second groove 073, which facilitates the pre-fixing of the third current collector 066 in the second groove 073.

[0443] In some embodiments, see below. Figure 32The included angle between the connecting part 077 and the heat-conducting part 666 is β, where 105°≤β≤135°. Specifically, the included angle between the second inner sidewall 075 and the second bottom wall 074 can be 105°, 106°, 107°, 108°, 109°, 110°, 111°, 112°, 113°, 114°, 115°, 116°, 117°, 118°, 119°, 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 131°, 132°, 133°, 134°, or 135°. It should be noted that the values ​​of γ and β can be set to the same or different, depending on the actual situation. Considering the convenience of welding and assembly, the values ​​of γ and β are generally set to be the same. More specifically, as an optional embodiment, the included angle between the second inner sidewall 075 and the second bottom wall 074 is 120°, and the included angle between the connecting part 077 and the heat-conducting part 666 is 120°. This setting can ensure the strength of the shell 031, and at the same time, the connecting part 077 and the second inner sidewall 075 of the second groove 073 can fit more tightly, which is conducive to heat transfer, and it can also facilitate the welding of the heat-conducting part 666 and the second bottom wall 074.

[0444] In some embodiments, the side of the end plate 067 facing the first cooling plate 062 is planar. This planar design facilitates heat transfer and improves cooling efficiency.

[0445] In some embodiments, please refer to Figure 33 The cooling device 061 further includes a cooling assembly 078, which includes a plurality of second cooling plates 079 extending from the side of the first cooling plate 062 near the battery cell 003. The plurality of second cooling plates 079 are connected to the first cooling plate 062, and the second cooling plates 079 are thermally connected to the radial sidewall of the battery cell. In this embodiment, each second cooling plate 079 includes an inlet end and an outlet end arranged opposite to each other. During cooling, the cooling medium enters the second cooling plate 079 from the inlet end and flows out of the second cooling plate 079 from the outlet end. Further, the cooling assembly 078 also includes a plurality of connectors 120. A connector 120 is provided between every two adjacent second cooling plates 079. One end of the connector 120 is connected to the inlet end of one of the second cooling plates 079, and the other end is connected to the outlet end of the other second cooling plate 079. In this way, the plurality of second cooling plates 079 are connected sequentially through the plurality of connectors 120.

[0446] In some embodiments, a plurality of second cooling plates 079 are integrally formed with a plurality of connectors 120.

[0447] Additionally, in this embodiment, please refer to Figure 33To improve cooling efficiency, the second cooling plate 079 is designed as a serpentine tube. The shape of the serpentine tube is adapted to the shape of the battery cell 003, thereby increasing the contact area between the second cooling plate 079 and the battery cell 003 and improving heat dissipation capacity.

[0448] It should be noted that in this embodiment, the cooling device 061 cools the multiple battery cells 003 axially through the first cooling plate 062 and simultaneously cools the battery cells 003 radially through the multiple second cooling plates 079. The first cooling plate 062 and the second cooling plate 079 cooperate with each other to improve cooling efficiency. With this configuration, the upper end of the battery module 060 (which can be in contact with air and dissipate heat on its own), the lower end of the battery module 060 (which dissipates heat through the first cooling plate 062), and the middle part of the battery module 060 (which dissipates heat through the second cooling plate 079) can be better controlled in terms of temperature, thus avoiding thermal runaway.

[0449] The cooling device 061 also includes a third cooling plate 121a. One end of the third cooling plate 121a is connected to the cooling component 078, and the other end is connected to the first cooling plate 062, thereby forming a cooling circuit. In this embodiment, the water inlet of the cooling device 061 is set on the cooling component 078, and the water outlet of the cooling device 061 is set on the first cooling plate 062. During the cooling process, the cooling medium enters the cooling component 078 from the water inlet, then flows from the cooling component 078 to the third cooling plate 121a, then flows from the third cooling plate 121a to the first cooling plate 062, and flows out from the water outlet on the first cooling plate 062, thus completing the heat exchange.

[0450] Please see Figure 35 , Figure 35 This is a schematic diagram of the structure of a battery pack 004 provided in an embodiment of this application. The battery pack 004 includes a battery case 041 and the aforementioned battery cells 003. The battery case 041 has a receiving cavity. Multiple battery cells 003 are disposed within the receiving cavity.

[0451] In this embodiment, by using the aforementioned cell 003, the current transmission inside the battery pack 004 can be smoother, the charging and discharging efficiency of the battery pack 004 can be higher, and the energy loss can be smaller.

[0452] Please see Figure 36 , Figure 36 This is a schematic diagram of the structure of an electrical device 005 provided in an embodiment of this application. An embodiment of this application provides an electrical device 005, which includes the aforementioned battery cell 003 or battery pack 004, wherein the battery pack 004 or battery cell 003 supplies power to the electrical device.

[0453] It is understood that electrical equipment 005 includes, but is not limited to, electric toys, power tools, electric vehicles, automobiles, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc. Automobiles can include gasoline-powered cars, natural gas-powered cars, and new energy vehicles.

[0454] In this embodiment, by using the aforementioned battery pack 004, the charging efficiency of the electrical device 005 can be improved, the energy utilization rate of the electrical device 005 can be increased, and the energy loss of the electrical device 005 can be reduced.

[0455] The following detailed description of the battery module 060 provided in the embodiments of this application, in conjunction with specific examples and data, should be understood as follows: the following examples are merely illustrative of the embodiments of this application and are not intended to limit the scope of this application.

[0456] It should be noted that the following embodiments all use cell 003 as an example for testing. The entire battery pack 004 is in operation, and the test is performed based on one cell 003. The parameters of cell 003 involve S1, S2, W1, W2, W3, and S3.

[0457] Test plan: such as Figure 34 As shown, the temperature test point T is the central hole 016 in the middle region of the cell 003. The temperature at this point is collected to determine the heat conduction and heat dissipation capabilities of the third current collector 066.

[0458] Test method:

[0459] 1. Charge the battery pack 004 using the CCCV charging method at a charging current of 0.5C. When the voltage of the battery pack 004 reaches 4.25V, charge it at a constant voltage of 4.25V. When the charging current drops to 0.02C, stop charging the battery pack 004 and let it rest for 10 minutes.

[0460] 2. Discharge the battery pack 004 with a charging current of 3.0C until the temperature of the temperature test point of the cell 003 of the battery pack 004 reaches 80℃; then let it rest at 35℃ for 30 minutes until the temperature of the temperature test point of the cell 003 reaches 35℃.

[0461] 3. Repeat step 2 until 10% SOC is reached, and check the highest temperature of part 004 inside the battery pack.

[0462] Basic group 1, control group 1 and control group 2 were set up. The parameters of basic group 1, control group 1 and control group 2 were exactly the same. Among them, control group 1 did not have the first cooling plate 062, and control group 2 did not have the second groove 073 on the end plate 067 of the shell 031. The specific test results are shown in Table 1.

[0463] Table 1. Test results of baseline group 1, control group 1, and control group 2

[0464] <![CDATA[S1 / mm 2 ]]> <![CDATA[S2 / mm 2 ]]> <![CDATA[S3 / mm 2 ]]> W1 / mm W2 / mm W3 / mm Maximum temperature / °C Basic Group 1 315 1451.4 28.26 0.35 0.7 0.15 55 Control group 1 315 1451.4 28.26 0.35 0.7 0.15 68 Control group 2 315 1451.4 28.26 / 0.7 0.15 60

[0465] According to the verification results in Table 1, the battery pack 004 of the basic group 1 is provided with a first cooling plate 062, and the internal temperature of the battery pack 004 is lower than that of the control group 1. The end plate 067 of the housing 031 of the cell 003 of the basic group 1 is provided with a second groove 073, and the temperature of the battery pack 004 is lower than that of the control group 2. In summary, the battery pack 004 provided by this application has a high cooling efficiency and can be used in fast charging and fast discharging applications such as high-rate discharge.

[0466] Using the basic group 1 as the parameter standard, S1 and S2 were changed, and the specific test results are shown in Table 2.

[0467] Table 2 Test results of Examples 1-4 and Comparative Examples 1-2

[0468]

[0469] According to the verification results in Table 2, the area of ​​the first heat-conducting surface 071 in Example 1 is smaller than that in Example 2, and the temperature of the battery pack 004 in Example 2 is lower than that in Example 1. The welding area in Example 3 is smaller than that in Example 4, and the temperature of the battery pack 004 in Example 4 is lower than that in Example 3. The area of ​​the first heat-conducting surface 071 in Comparative Example 1 is smaller than that in Examples 1 and 2, and the temperature of the battery pack 004 in Comparative Example 1 is higher than that in Examples 1 and 2. The welding area in Comparative Example 2 is smaller than that in Examples 3 and 4, and therefore the temperature of the battery pack 004 in Comparative Example 2 is higher than that in Examples 3 and 4.

[0470] Using the basic group 1 as the parameter standard, W1, W2 and W3 were changed, and the specific test results are shown in Table 3.

[0471] Table 3 Test results of Examples 5-8 and Comparative Examples 3-4

[0472]

[0473] As shown in Table 3, the ratio of W1 to W2 in Comparative Example 3 is greater than 0.6. Compared with Examples 5 and 6, the temperature of the battery pack 004 in Comparative Example 3 is significantly higher than that in Examples 5 and 6. In Comparative Example 4, the ratio of W3 to W1 is greater than 1.2. The thickness of the second bottom wall 074 of the heat-conducting part 666 and the second groove 073 is relatively thick. During the welding process, a false weld phenomenon occurs, and leakage occurs during the actual test. The battery pack 004 provided in Comparative Example 4 cannot be used normally.

[0474] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery cell, characterized in that, include: The shell has a receiving cavity; A core is disposed within the receiving cavity. The core includes a first pole piece, a second pole piece, and a diaphragm disposed between the first pole piece and the second pole piece. The first pole piece and the second pole piece have opposite polarities. Along the axial direction of the core, the core body has a first end and a second end. A first electrode tab is disposed at the first end and connected to the first electrode plate; The second electrode tab is disposed at the first end and connected to the second electrode plate; A third electrode tab is disposed at the second end, and the third electrode tab is connected to the first electrode or the second electrode. A first output electrode and a second output electrode are disposed in the housing, wherein the first output electrode is electrically connected to the first electrode ear and the second output electrode is electrically connected to the second electrode ear.

2. The battery cell according to claim 1, characterized in that, The multiple layers of the third tab are bent and stacked to form a third tab region, which extends in a closed or open ring along the circumference of the core body.

3. The battery cell according to claim 2, characterized in that, Along the radial direction of the core, from the center of the core body outward, the second end is sequentially provided with a first central loop area and a third pole loop area.

4. The battery cell according to claim 3, characterized in that, The inner diameter of the third tab area is C, and the outer diameter of the core body is A, satisfying: 3%A≤C≤30%A.

5. The battery cell according to claim 2, characterized in that, Along the radial direction of the core, from the center of the core body outward, the second end is sequentially provided with the third pole lug region and the first peripheral hollow lug region.

6. The battery cell according to claim 5, characterized in that, The outer diameter of the third tab region is D, and the outer diameter of the core body is A, satisfying: 65%A≤D≤80%A.

7. The battery cell according to any one of claims 1-6, characterized in that, The third electrode tab is connected to the first electrode plate. The plane perpendicular to the axis of the core body is the projection plane, and the axis of the core body is the projection direction. In the projection plane, the projection of the first electrode tab before bending and the projection of the third electrode tab before bending at least partially overlap. Alternatively, the third electrode tab is connected to the second electrode plate, with a plane perpendicular to the axis of the core body as the projection plane and the axis of the core body as the projection direction. In the projection plane, the projection of the second electrode tab before bending and the projection of the third electrode tab before bending at least partially overlap.

8. The battery cell according to claim 1, characterized in that, The core also includes a fourth electrode tab, which is disposed at the second end of the core body. One of the third electrode tab and the fourth electrode tab is connected to the first electrode plate, and the other is connected to the second electrode plate.

9. The battery cell according to claim 8, characterized in that, The third electrode lugs are bent and stacked in multiple layers to form a third electrode lug area, and the fourth electrode lugs are bent and stacked in multiple layers to form a fourth electrode lug area. Along the radial direction of the core body, from the center of the core body outward, the second end is sequentially provided with the fourth electrode lug area, the first middle ring hollow lug area and the third electrode lug area. The fourth electrode lug area and the third electrode lug area extend along the circumference of the core body to form a closed or open ring.

10. The battery cell according to claim 8, characterized in that, Multiple layers of the third electrode lugs are bent and stacked to form a third electrode lug region, and multiple layers of the fourth electrode lugs are bent and stacked to form a fourth electrode lug region. Along the radial direction of the core body, from the center of the core body outward, the second end is sequentially provided with a third central hollow lug region, the fourth electrode lug region, and the third electrode lug region. The fourth electrode lug region and the third electrode lug region extend along the circumference of the core body to form a closed or open ring.

11. The battery cell according to claim 10, characterized in that, The inner diameter of the fourth tab region is J, and the outer diameter of the core body is A, satisfying: 3%A≤J≤22%A.

12. The battery cell according to claim 8, characterized in that, The third electrode lugs are bent and stacked in multiple layers to form a third electrode lug area, and the fourth electrode lugs are bent and stacked in multiple layers to form a fourth electrode lug area. Along the radial direction of the core body, from the center of the core body outward, the second end is sequentially provided with the fourth electrode lug area, the third electrode lug area and the third peripheral hollow lug area. The fourth electrode lug area and the third electrode lug area extend along the circumference of the core body to form a closed or open ring.

13. The battery cell according to claim 12, characterized in that, The outer diameter of the third tab region is D, and the outer diameter of the core body is A, satisfying: 85%A≤D<100%A.

14. The battery cell according to any one of claims 9-13, characterized in that, The outer diameter of the core body is A, and the outer diameter of the fourth tab region is I, satisfying: 25%A≤I≤35%A; and / or, the inner diameter of the third tab region is C, satisfying: 40%A≤C≤75%A.

15. The battery cell according to any one of claims 8-13, characterized in that, The third electrode is connected to the first electrode.

16. The battery cell according to claim 15, characterized in that, Using a plane perpendicular to the axis of the core body as the projection plane and the axial direction of the core body as the projection direction, the projection of the first tab before bending and the projection of the third tab before bending partially overlap in the projection plane.

17. The battery cell according to any one of claims 8-13, characterized in that, The fourth electrode is connected to the second electrode plate.

18. The battery cell according to claim 17, characterized in that, Using a plane perpendicular to the axis of the core body as the projection plane and the axial direction of the core body as the projection direction, the projection of the second pole lug before bending and the projection of the fourth pole lug before bending are at least partially overlapped in the projection plane.

19. The battery cell according to claim 1, characterized in that, Multiple layers of the first electrode tab are bent and stacked to form a first electrode tab area, and multiple layers of the second electrode tab are bent and stacked to form a second electrode tab area. Along the radial direction of the core body, from the center of the core body outward, the first end is sequentially provided with a first electrode tab area, a second central loop hollow area and a second electrode tab area. The first electrode tab area and the second electrode tab area extend along the circumference of the core to form a closed or open ring.

20. The battery cell according to claim 1, characterized in that, Multiple layers of the first electrode tab are bent and stacked to form a first electrode tab region, and multiple layers of the second electrode tab are bent and stacked to form a second electrode tab region. Along the radial direction of the core body, from the center of the core body outward, the first end is sequentially provided with a second central hollow tab region, a first electrode tab region, and a second electrode tab region.

21. The battery cell according to claim 20, characterized in that, The inner diameter of the first tab area is M, and the outer diameter of the core body is A, satisfying: 3%A≤M≤22%A.

22. The battery cell according to claim 1, characterized in that, Multiple layers of the first electrode tab are bent and stacked to form a first electrode tab area, and multiple layers of the second electrode tab are bent and stacked to form a second electrode tab area. Along the radial direction of the core body, from the center of the core body outward, the first end is sequentially provided with the first electrode tab area, the second electrode tab area and the second peripheral hollow tab area.

23. The battery cell according to claim 22, characterized in that, The outer diameter of the second electrode ear region is E, and the outer diameter of the core body is A, satisfying: 85%A≤E<100%A.

24. The battery cell according to any one of claims 19-23, characterized in that, The outer diameter of the core body is A, and the outer diameter of the first tab region is G, satisfying: 35%A≤G≤50%A; and / or, the inner diameter of the second tab region is F, satisfying: 60%A≤F≤75%A.

25. The battery cell according to claim 24, characterized in that, FG≥4mm.

26. The battery cell according to any one of claims 19-23, characterized in that, The outer diameter of the second tab region is E, and the inner diameter of the second tab region is F, satisfying: EF≥4mm.

27. The battery cell according to any one of claims 1-6 or 8-13, characterized in that, The first electrode is the positive electrode, and the second electrode is the negative electrode.

28. The battery cell according to claim 1, characterized in that, The first output electrode is the electrode post assembly, and the second output electrode is the cover plate body. The cover plate body is closed with the housing to seal the receiving cavity. The electrode post assembly is installed on the cover plate body and electrically connected to the first electrode tab. The cover plate body is provided with a recessed portion, which is electrically connected to the second electrode tab.

29. The battery cell according to claim 28, characterized in that, The recessed portion is provided with a welding plate for welding connection. The welding plate is electrically connected to the second electrode ear. The thickness of the welding plate is less than the thickness of the area of ​​the cover plate body where the recessed portion is not provided.

30. The battery cell according to claim 29, characterized in that, The battery cell also includes a first current collector and a second current collector, which are located at the same end of the core. The first current collector is welded to the second electrode tab and the welding plate, and the second current collector is electrically connected to the first electrode tab and the electrode post assembly.

31. The battery cell according to claim 30, characterized in that, The thickness of the welding plate is H1, and the thickness of the first current collector is H2, where H2 = bH1, satisfying: 0.5 ≤ b ≤ 1.

2.

32. The battery cell according to claim 29, characterized in that, The thickness of the welding plate is H1, and the thickness of the area of ​​the cover plate body where the recess is not provided is H, H1=aH, satisfying: 0.5≤a≤0.

7.

33. The battery cell according to claim 29 or 30, characterized in that, The cover plate body has a base plate for defining the bottom of the recess, and the welding plate is disposed on the base plate.

34. The battery cell according to claim 33, characterized in that, The cover plate body also has a side plate connected to the bottom plate to form the recess together with the bottom plate. The bottom plate is electrically connected to the second electrode ear. The thickness of the welding plate is H1, and the thickness of the side plate is H4, where cH4=H1, satisfying: 0.3≤c≤0.

6.

35. The battery cell according to claim 34, characterized in that, The recessed portion includes a first bent connecting portion and a second bent connecting portion. The first bent connecting portion is connected between the side plate and the bottom plate, and the second bent connecting portion is connected between the side plate and the area of ​​the cover plate body where the recessed portion is not provided. The thickness of the area of ​​the cover plate body without the recess is H, the radius of curvature of the first bending connection is R1, and the radius of curvature of the second bending connection is R2, where R1 = mH and R2 = nH, satisfying: 0.8 ≤ m ≤ 2 and 0.1 ≤ n ≤ 1.

36. The battery cell according to claim 35, characterized in that, R1 = pR2, satisfying: 0.15 ≤ p ≤ 0.

5.

37. The battery cell according to claim 34, characterized in that, The recessed portion includes a first bent connection portion, which is connected between the side plate and the bottom plate. The thickness of the first bent connection portion gradually decreases along the direction from the side plate to the bottom plate.

38. The battery cell according to any one of claims 28-31, characterized in that, The thickness of the area of ​​the cover plate body without the recess is H, the width of the recess is L1, and the depth of the recess is L2, where L1 = dH and L2 = eH, satisfying: 2.5 ≤ d ≤ 5 and 1.5 ≤ e ≤ 3.

5.

39. The battery cell according to any one of claims 28-32, characterized in that, The recessed portion protrudes toward the receiving cavity.

40. The battery cell according to any one of claims 28-32, characterized in that, The diameter of the circle containing the outer contour of the orthographic projection of the shell on the horizontal plane is D1, and the diameter of the circle containing the center line of the orthographic projection of the recess on the horizontal plane is D2, where D2 = fD1, satisfying: 0.5 ≤ f ≤ 0.

8.

41. The battery cell according to any one of claims 28-32, characterized in that, The cross-sectional shape of the recessed portion includes any one of U-shape, V-shape, and W-shape.

42. The battery cell according to any one of claims 30-32, characterized in that, It also includes a first insulating element, which is disposed between the first current collector and the second current collector.

43. The battery cell according to claim 28, characterized in that, The cover plate body includes: The first cover plate portion is provided with a first hole and an explosion-proof groove, the pole assembly is inserted into the first hole, and the explosion-proof groove is provided on the outside of the first hole; The second cover plate is connected between the outer periphery of the first cover plate and the housing. The recessed portion is disposed on the second cover plate portion and adjacent to the explosion-proof groove, and the recessed portion is connected to the second electrode tab.

44. The battery cell according to claim 43, characterized in that, The diameter of the circle containing the outer contour of the shell projected along its axial direction is D1, the diameter of the circle containing the center line of the orthographic projection of the explosion-proof marking on the horizontal plane is D3, and the diameter of the circle containing the center line of the orthographic projection of the recess on the horizontal plane is D2, where D3 = a'D1, D2 = fD1, satisfying: 0.4≤a'≤0.75, 0.5≤f≤0.

8.

45. The battery cell according to claim 44, characterized in that, The thickness of the cover plate body is H, where D2-D3=2c'H, c'>3.

46. ​​The battery cell according to claim 43, characterized in that, The recessed portion is configured such that one side of the second cover plate portion is recessed into the receiving cavity.

47. The battery cell according to claim 46, characterized in that, The thickness of the area of ​​the second cover plate without the recess is H, the thickness of the area of ​​the first cover plate without the explosion-proof marking is H6, the marking depth of the explosion-proof marking is H32, (H6-H32)=qH, satisfying: 0.1≤q≤0.

3.

48. The battery cell according to any one of claims 43-47, characterized in that, The cover plate body is in a normal state. In the normal state, the first cover plate part is also provided with a first groove. The first groove has a first bottom wall and a first inner side wall connected to the first bottom wall. The explosion-proof groove is provided on the first bottom wall.

49. The battery cell according to claim 48, characterized in that, The thickness of the area of ​​the first cover plate without the first groove is H3, the width of the first groove is H40, the depth of the first groove is H50, and the thickness of the area of ​​the first bottom wall without the explosion-proof marking is H6, where H40 = k'H3, H50 = m'H3, and H6 = n'H3, satisfying: 2≤k'≤5, 1≤m'≤2, and 0.5≤n'≤1.

50. The battery cell according to claim 48, characterized in that, The first inner sidewall is inclined relative to the first bottom wall, and the angle between the first inner sidewall and the first bottom wall is α, where 55°≤α≤135°.

51. The battery cell according to claim 48, characterized in that, The first groove protrudes toward the receiving cavity, and the cover plate body also has an abnormal state, wherein the first cover plate portion of the cover plate body in the abnormal state is flatter than the first cover plate portion of the cover plate body in the normal state.

52. The battery cell according to any one of claims 43-47, characterized in that, It also includes a second insulating component. The first cover plate includes a first connecting plate and a second connecting plate connected to the outer periphery of the first connecting plate. The explosion-proof groove is provided on the second connecting plate. The second insulating element is disposed between the pole assembly and the first connecting plate, and abuts against the second connecting plate; The first hole is located on the first connecting plate.

53. The battery cell according to claim 52, characterized in that, The second insulating member includes a first insulating part and a second insulating part, the first connecting plate is located between the first insulating part and the second insulating part, and the inner peripheral side of the first insulating part passes through the first hole and is connected to the inner peripheral side of the second insulating part; The second insulating portion is located on the side of the first connecting plate near the receiving cavity. The second connecting plate is recessed towards the receiving cavity to form a recessed structure, and the outer peripheral side of the second insulating portion abuts against the recessed structure.

54. The battery cell according to any one of claims 43-47, characterized in that, The explosion-proof grooves are arranged around the first hole.

55. The battery cell according to any one of claims 43-47, characterized in that, When the air pressure in the receiving cavity is the first air pressure, the pole assembly is disconnected from the winding core; When the air pressure inside the accommodating cavity is the second air pressure, the cover plate body cracks at the explosion-proof notch. Wherein, the first air pressure is P1, the second air pressure is P2, 1.2Mpa≤P1≤1.8Mpa, P2>1.8Mpa.

56. The battery cell according to claim 1, characterized in that, The first electrode tab, the second electrode tab, and the third electrode tab are die-cut electrode tabs.

57. The battery cell according to claim 56, characterized in that, The die-cut width of the die-cut tab is W0, which satisfies 2mm≤W0≤6mm.

58. The battery cell according to claim 56, characterized in that, The die-cutting angle of the die-cut tab is α0, which satisfies 55°≤α0≤85°.

59. The battery cell according to claim 56, characterized in that, The die-cut height of the die-cut tab is H0, which satisfies: 5mm≤H0≤7.5mm.

60. A battery module, characterized in that, include: Cooling device, including a first cooling plate; And, in any one of claims 1-59, there are multiple battery cells, each of the battery cells further includes a third current collector, and the portion of the housing near the third tab is an end plate; The third current collector is located between the end plate and the third electrode tab and is electrically connected to the third electrode tab. The third current collector includes a heat-conducting part, which is connected to the end plate. The side of the end plate opposite to the winding core is connected to the first cooling plate.

61. The battery module according to claim 60, characterized in that, The heat-conducting part includes a first heat-conducting surface facing the end plate, the first heat-conducting surface being connected to the end plate, the end plate including a second heat-conducting surface facing the first cooling plate, the second heat-conducting surface being connected to the first cooling plate, the area of ​​the first heat-conducting surface being S1, the area of ​​the second heat-conducting surface being S2, wherein S1:S2 = (0.05~0.25):

1.

62. The battery module according to claim 61, characterized in that, The third current collector is welded to the end plate.

63. The battery module according to claim 62, characterized in that, The welding area between the third current collector and the end plate is S3, where S3:S2 = (0.01~0.05):

1.

64. The battery module according to claim 60 or 61, characterized in that, The end plate has a second groove with an opening facing the winding core. The second groove has a second bottom wall and a second inner side wall connected to the second bottom wall. The heat-conducting part is disposed in the second groove and connected to the second bottom wall.

65. The battery module according to claim 64, characterized in that, The second inner sidewall is inclined relative to the second bottom wall, and the angle between the second inner sidewall and the second bottom wall is γ, wherein 105°≤γ≤135°.

66. The battery module according to claim 64, characterized in that, The end plate has a first portion and a second portion disposed around the first portion, and the second groove is formed on the first portion; The vertical distance between the second bottom wall and the side of the end plate opposite to the core is W1, and the thickness of the second part is W2, wherein W1:W2 = (0.3~0.6):

1.

67. The battery module according to claim 64, characterized in that, The vertical distance between the second bottom wall of the second groove and the side of the end plate opposite to the core is W1, and the thickness of the heat-conducting part is W3, wherein W3:W1 = (0.2~1.2):

1.

68. The battery module according to claim 60 or 61, characterized in that, The core has tabs of the same polarity at both ends. The cell also includes a first current collector connected to the tabs away from the first cooling plate, and a third current collector connected to the tabs close to the first cooling plate.

69. The battery module according to claim 60 or 61, characterized in that, The first current collector further includes a current collecting part and a connecting part. The current collecting part is connected to the winding core, and the connecting part is connected between the current collecting part and the heat-conducting part. The connecting part is inclined relative to the heat-conducting part.

70. The battery module according to claim 69, characterized in that, The included angle between the connecting part and the heat-conducting part is β, where 105°≤β≤135°.

71. The battery module according to claim 60 or 61, characterized in that, The side of the end plate facing the first cooling plate is a plane.

72. The battery module according to claim 60 or 61, characterized in that, The cooling device further includes a cooling assembly comprising a plurality of second cooling plates extending from the first cooling plate near the side of the battery cell, the plurality of second cooling plates communicating with the first cooling plate, and the second cooling plates being thermally connected to the radial sidewall of the battery cell.

73. A battery pack, characterized in that, It includes a housing and a battery module as described in any one of claims 60-72, wherein the battery module is installed in the housing.

74. An electrical appliance, characterized in that, The device includes a battery cell as described in any one of claims 1-59, a battery module as described in any one of claims 60-72, or a battery pack as described in claim 73, wherein the battery cell, battery module, or battery pack supplies power to the electrical device.

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