Battery cell, battery module, battery pack and electric equipment

Abstract

The utility model 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] The present application relates to the field of battery technology, and in particular to a battery cell, a battery module, a battery pack and an electrical device. Background Art

[0002] In the related art, the battery cell includes a shell and a winding core arranged in the shell. The winding core includes a positive electrode sheet, a diaphragm and a negative electrode sheet that are stacked and wound in sequence. Usually, the positive and negative electrodes of the battery cell can be output on the same side, or they can be output from both ends of the battery cell respectively. In the structure in which the positive and negative electrodes are output on the same side, the shell of the battery cell is generally used as the output electrode of the negative electrode. At the same time, the installation position for installing the pole is insulated and isolated on the top cover sheet of the shell by a seal, and the pole is set in the installation position as the output electrode of the positive electrode. A positive electrode ear and a negative electrode ear are respectively provided at one end of the winding core close to the top cover sheet. The negative electrode ear is connected to the top cover sheet, and the positive electrode ear is connected to the pole, so that the positive and negative electrodes of the battery cell are respectively led out from the same end of the battery cell. In the structure where the positive and negative electrodes are output from both ends of the battery cell, the positive electrode ear and the negative electrode ear are respectively located at the two ends of the winding core, the positive electrode ear is connected to the positive electrode column, and the negative electrode ear is connected to the negative electrode column or the outer shell of the battery cell, thereby leading the positive and negative electrodes of the battery cell out from the two ends of the battery cell.

[0003] In the above solution, although the current collecting capacity of the battery cell basically meets the application requirements of the battery cell, there is still room for improvement in the current collecting capacity of the battery cell. Utility Model Content

[0004] The embodiments of the present application provide a battery cell, a battery module, a battery pack, and an electrical device, which can improve the current collecting capacity of the battery cell.

[0005] In the first aspect, an embodiment of the present application provides a battery cell, which includes a shell, a winding core, a first pole piece, a second pole piece, a third pole piece, a first output pole and a second output pole; the shell has a accommodating cavity; the winding core is arranged in the accommodating cavity, and the winding core includes a first pole piece, a second pole piece and a diaphragm arranged between the first pole piece and the second pole piece, the polarity of the first pole piece and the second pole piece are opposite, and along the axial direction of the winding core, the winding core body has a first end and a second end; the first pole piece is arranged at the first end and is connected to the first pole piece; the second pole piece is arranged at the first end and is connected to the second pole piece; the third pole piece is arranged at the second end, and the third pole piece is connected to the first pole piece or the second pole piece; the first output pole and the second output pole are arranged in the shell, the first output pole is electrically connected to the first pole piece, and the second output pole is electrically connected to the second pole piece.

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

[0007] In one embodiment, along the radial direction of the winding core, from the center of the winding core body to the outside, the second end is sequentially provided with a first central hollow lug area and a third tab area.

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

[0009] In one embodiment, along the radial direction of the winding core, from the center of the winding core body to the outside, the second end is sequentially provided with a third tab area and a first peripheral hollow tab area.

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

[0011] In one embodiment, the third pole tab is connected to the first pole piece, and the 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 pole tab before bending and the projection of the third pole tab before bending at least partially overlap; or, the third pole tab is connected to the second pole piece, and the 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 pole tab before bending and the projection of the third pole tab before bending at least partially overlap.

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

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

[0014] In one embodiment, multiple layers of third pole tabs are bent and stacked to form a third pole tab area, and multiple layers of fourth pole tabs are bent and stacked to form a fourth pole tab area. Along the radial direction of the core body, from the center of the core body to the outside, the second end is sequentially provided with a third central hollow tab area, a fourth pole tab area and a third pole tab area, and the fourth pole tab area and the third pole tab area respectively extend along the circumference of the core body into closed or open rings.

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

[0016] In one embodiment, multiple layers of third pole tabs are bent and stacked to form a third pole tab area, and multiple layers of fourth pole tabs are bent and stacked to form a fourth pole tab area. Along the radial direction of the core body, from the center of the core body to the outside, the second end is sequentially provided with the fourth pole tab area, the third pole tab area and the third peripheral hollow tab area, and the fourth pole tab area and the third pole tab area respectively extend along the circumference of the core body into closed or open rings.

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

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

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

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

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

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

[0023] In one embodiment, multiple layers of first pole ears are bent and stacked to form a first pole ear area, and multiple layers of second pole ears are bent and stacked to form a second pole ear area. Along the radial direction of the core body, from the center of the core body to the outside, the first end is sequentially provided with the first pole ear area, the second middle ring hollow ear area and the second pole ear area, and the first pole ear area and the second pole ear area respectively extend along the circumference of the core into closed or open rings.

[0024] In one embodiment, multiple layers of first pole tabs are bent and stacked to form a first pole tab area, and multiple layers of second pole tabs are bent and stacked to form a second pole tab area. Along the radial direction of the winding core body, from the center of the winding core body to the outside, the first end is sequentially provided with a second central hollow tab area, a first pole tab area and a second pole tab area.

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

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

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

[0028] In one embodiment, the outer diameter of the winding core body is A, the outer diameter of the first tab region is G, and the following conditions are met: 35%A≤G≤50%A; and / or the inner diameter of the second tab region is F, and the following conditions are met: 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 tab is a positive electrode tab, and the second electrode tab is a negative electrode tab.

[0032] In one embodiment, the first output pole is a pole assembly, and the second output pole is a cover body, which is covered with the shell to close the accommodating cavity; the pole assembly is installed on the cover body and is electrically connected to the first pole ear; wherein the cover body is provided with a recessed portion, which is electrically connected to the second pole ear.

[0033] In one embodiment, the recessed portion is provided with a welding plate for welding connection, the welding plate is electrically connected to the second tab, and the thickness of the welding plate is smaller than the thickness of the region of the cover plate body where the recessed portion is not provided.

[0034] In one embodiment, the battery cell further includes a first current collecting member and a second current collecting member, the first current collecting member and the second current collecting member are located at the same end of the winding core, the first current collecting member is welded to the second pole lug and the welding plate, and the second current collecting member is electrically connected to the first pole lug and the pole assembly.

[0035] In one embodiment, the thickness of the welding plate is H1, the thickness of the first current collecting member is H2, H2=bH1, and the relationship 0.5≤b≤1.2 is satisfied.

[0036] In one embodiment, the thickness of the welding plate is H1, and the thickness of the region of the cover plate body where the recessed portion is not provided is H, H1=aH, satisfying: 0.5≤a≤0.7.

[0037] In one embodiment, the cover plate body has a bottom plate for defining a recessed bottom, and the welding plate is disposed on the bottom 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 tab. 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 connection portion and a second bent connection portion, the first bent connection portion is connected between the side plate and the bottom plate, and the second bent connection 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 curvature radius of the first bent connection portion is R1, and the curvature radius of the second bent connection portion is R2, wherein R1=mH, R2=nH, satisfying: 0.8≤m≤2, 0.1≤n≤1.

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

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

[0042] In one embodiment, the thickness of the region of the cover body where no recess is provided is H, the width of the recess is L1, and the depth of the recess is L2, wherein L1 = dH, L2 = eH, satisfying: 2.5≤d≤5, 1.5≤e≤3.5.

[0043] In one embodiment, the recessed portion protrudes toward the accommodating cavity.

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

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

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

[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 notch, the pole assembly is passed through the first hole, and the explosion-proof notch is provided outside the first hole; the second cover plate portion is connected between the outer periphery of the first cover plate portion and the shell; wherein, the recessed portion is provided in the second cover plate portion and is adjacent to the explosion-proof notch, and the recessed portion is connected to the second pole ear.

[0048] In one embodiment, the diameter of the circle where the outer contour of the shell is projected along its axial direction is D1, the diameter of the circle where the center line of the orthographic projection of the explosion-proof notch on the horizontal plane is D3, and the diameter of the circle where the center line of the orthographic projection of the recessed portion on the horizontal plane is D2, wherein D3 = a'D1, D2 = fD1, and the following conditions are satisfied: 0.4≤a'≤0.75, 0.5≤f≤0.8.

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

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

[0051] In one embodiment, the thickness of the area of ​​the second cover portion where the recess is not provided is H, the thickness of the area of ​​the first cover portion where the explosion-proof notch is not provided is H6, the notch depth of the explosion-proof notch is H32, (H6-H32)=qH, satisfying: 0.1≤q≤0.3.

[0052] In one embodiment, the cover body has a normal state. In the normal state, the first cover 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. The explosion-proof notch is provided on the first bottom wall.

[0053] In one embodiment, the thickness of the area of ​​the first cover portion where the first groove is not provided is H3, the groove 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 where the explosion-proof notch is not provided is H6, wherein H40=k'H3, H50=m'H3, H6=n'H3, and the following conditions are satisfied: 2≤k'≤5, 1≤m'≤2, 0.5≤n'≤1.

[0054] In one embodiment, the first inner sidewall is inclined relative to the first bottom wall, and an 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 accommodating cavity, and the cover body further has an abnormal state, wherein the first cover portion of the cover body in the abnormal state is flatter than the first cover portion of the cover body in the normal state.

[0056] In one embodiment, a second insulating member is further included, the first cover portion includes a first connecting plate and a second connecting plate connected to the outer periphery of the first connecting plate, and the explosion-proof notch is 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; wherein the 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, the first connecting plate is located between the first insulating portion and the second insulating portion, and the inner circumference of the first insulating portion is connected to the inner circumference of the second insulating portion after passing through the first hole; wherein, the second insulating portion is located on the side of the first connecting plate close to the accommodating cavity, the second connecting plate is sunken toward the accommodating cavity to form a sunken structure, and the outer circumference of the second insulating portion abuts the sunken structure.

[0058] In one embodiment, the explosion-proof notch is arranged around the first hole.

[0059] In one embodiment, when the air pressure in the accommodating chamber is a first air pressure, the pole assembly is disconnected from the winding core; when the air pressure in the accommodating chamber is a second air pressure, the cover body ruptures 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.

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

[0061] In one embodiment, the die-cutting 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-cut height of the die-cut tab is H0, which satisfies: 5 mm ≤ H0 ≤ 7.5 mm.

[0064] On the second aspect, an embodiment of the present application provides 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 part of the shell close to the third pole ear is an end plate; wherein the third current collector is located between the end plate and the third pole ear, and is electrically connected to the third pole ear, 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 facing away from the winding core is connected to the first cooling plate.

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

[0066] In one embodiment, the third current collecting member is connected to the end plate by welding.

[0067] In one embodiment, the welding area between the third current collecting member 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 opening toward the winding core, the second groove has a second bottom wall and a second inner side wall connected to the second bottom wall, and the heat conducting portion 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 an 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 portion and a second portion arranged 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 facing away from the winding core is W1, and the thickness of the second portion 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 surface of the end plate facing away from the winding core is W1, and the thickness of the heat conducting portion is W3, wherein W3:W1=(0.2-1.2):1.

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

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

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

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

[0076] In one embodiment, the cooling device further includes a cooling assembly, which includes a plurality of second cooling plates extending from the first cooling plate close to the battery cell. The plurality of second cooling plates are connected to the first cooling plate, and the second cooling plates are thermally conductively connected to the radial side wall of the battery cell.

[0077] In a third aspect, an embodiment of the present application provides a battery pack, which includes a box and the aforementioned battery module, wherein the battery module is installed in the box.

[0078] In a fourth aspect, an embodiment of the present application provides an electrical device, which includes the aforementioned battery cell, or the aforementioned battery module, or the aforementioned battery pack, and the battery cell, battery module, or battery pack provides power for the electrical device.

[0079] Beneficial effects of the embodiments of the present application:

[0080] In the embodiments of the present application, a first tab and a second tab are provided at one end of the winding core to collect current for the positive and negative electrodes, respectively, and a third tab is provided at the other end of the winding core to collect current for the positive or negative electrode. This increases the current collecting area of ​​the electrode connected to the third tab, thereby increasing the number of electron conduction paths and improving the current collecting capacity of the electrode. This improves the current collecting capacity of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0082] Figure 1 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0083] Figure 2 Schematic diagram of the structure of the winding core provided in an embodiment of the present application;

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

[0085] Figure 4 is a structural diagram of the second end provided in an embodiment of the present application;

[0086] Figure 5 is a structural diagram of another second end provided in an embodiment of the present application;

[0087] Figure 6 Schematic diagram of the projection relationship between the third tab and the first tab before bending provided in an embodiment of the present application;

[0088] Figure 7 Schematic diagram of the projection relationship between the third tab and the second tab before bending provided in an embodiment of the present application;

[0089] Figure 8 is a structural schematic diagram of another winding core provided in an embodiment of the present application;

[0090] Figure 9 is a structural diagram of yet another second end provided in an embodiment of the present application;

[0091] Figure 10 Schematic diagram of the projection relationship between the fourth electrode tab and the second electrode tab before bending provided in an embodiment of the present application;

[0092] Figure 11is a structural diagram of the first end provided in an embodiment of the present application;

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

[0094] Figure 13 This is a schematic structural diagram of the cover body and the pole assembly in an embodiment of the present application;

[0095] Figure 14 yes Figure 1 A' in the middle is an enlarged schematic diagram;

[0096] Figure 15 yes Figure 1 A magnified schematic diagram of point B in the middle;

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

[0098] Figure 17 yes Figure 1 A schematic structural diagram of an embodiment of a medium-sized battery cell under a first gas pressure;

[0099] Figure 18 yes Figure 1 A schematic structural diagram of another embodiment of a medium-sized battery cell under a first gas pressure;

[0100] Figure 19 yes Figure 1 A schematic structural diagram of an embodiment of a medium-sized battery cell under a second gas pressure;

[0101] Figure 20 This is a schematic structural diagram of the cover body and the pole assembly provided in an embodiment of the present application;

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

[0103] Figure 22 yes Figure 21 The enlarged schematic diagram of point D in the middle;

[0104] Figure 23 yes Figure 21 The enlarged schematic diagram of point E in the middle;

[0105] Figure 24 yes Figure 21 The enlarged schematic diagram of point C in the middle;

[0106] Figure 25 A schematic diagram of the structure of the tab provided in the embodiment of the present application;

[0107] Figure 26 is a three-dimensional schematic diagram of a battery module provided in an embodiment of the present application;

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

[0109] Figure 28 yes Figure 27 Cross-sectional view of EE;

[0110] Figure 29 yes Figure 28 Middle F is an enlarged schematic diagram;

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

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

[0113] Figure 32 yes Figure 31 It is an enlarged schematic diagram at H;

[0114] Figure 33 is a schematic structural diagram of a cooling assembly provided in an embodiment of the present application;

[0115] Figure 34 Schematic diagram of temperature test points of a battery cell provided in an embodiment of the present application;

[0116] Figure 35 is a schematic structural diagram of a battery pack provided in an embodiment of the present application;

[0117] Figure 36 It is a structural diagram of the electrical equipment provided in the embodiment of the present application.

[0118] Description of reference numerals:

[0119] 001-winding core; 011-first pole lug; 111-first pole lug area; 012-second pole lug; 121-second pole lug area; 013-third pole lug; 131-third pole lug area; 014-fourth pole lug; 141-fourth pole lug area; 015-winding core body; 151-first pole piece; 152-second pole piece; 153-diaphragm; 1541-first central hollow lug area; 1542-second central hollow lug area; 1543-third central hollow lug area; 1544-first peripheral hollow lug area; 1545- Second peripheral hollow area; 1546 - third peripheral hollow area; 1547 - first middle ring hollow area; 1548 - second middle ring hollow area; 016 - middle hole; 003 - battery cell; 031 - housing; 311 - receiving chamber; 108 - cover plate body; 004 - battery pack; 041 - battery box; 005 - electrical equipment; 107 - pole assembly; 108 - cover plate body; 109 - recessed portion; 110 - first current collector; 111a - second current collector; 112 - bottom plate; 113 - side plate; 11 6-welding plate; 117a-first insulating member; 117-first bent connecting portion; 118-second bent connecting portion; 102-first cover portion; 103-first hole; 104-explosion-proof notch; 105-second cover portion; 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 member; 114b-first insulating portion; 115b-second insulating portion; 06 0-battery module; 061-cooling device; 062-first cooling plate; 066-third current collecting member; 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 wall; 076-current collecting part; 077-connecting part; 078-cooling assembly; 079-second cooling plate; 120-connecting head; 121a-third cooling plate. DETAILED DESCRIPTION

[0120] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts 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 understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the specified features. In the description of this application, "plurality" means two or more, unless otherwise specifically specified.

[0122] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0123] The terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

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

[0125] See also Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the structure of the battery cell 003 provided in an embodiment of the present application. Figure 2 Schematic diagram of the structure of the winding core 001 provided in the embodiment of the present application. The embodiment of the present application provides a battery cell 003. The battery cell includes a shell 031, a winding core 001, a first pole tab 011, a second pole tab 012, a third pole tab 013, a first output pole and a second output pole. The shell 031 has a receiving cavity 311. The winding core 001 is arranged in the receiving cavity 311. The winding core 001 includes a first pole piece 151, a second pole piece 152 and a diaphragm 153 provided between the first pole piece 151 and the second pole piece 152, as shown in FIG. Figure 3 As shown, Figure 3 yes Figure 2 Enlarged view of point A in the middle; Figure 3 for Figure 2 The enlarged partial cross-sectional view of the part shown at A in the figure shows a cross section of a first pole piece 151, a cross section of a second pole piece 152, and a cross section of the diaphragm 153. The polarity of the first pole piece 151 and the second pole piece 152 are opposite. Along the axial direction of the winding core 001, the winding core body 015 has a first end and a second end. The first pole tab 011 is arranged at the first end and is connected to the first pole piece 151. The second pole tab 012 is arranged at the first end and is connected to the second pole piece 152. The third pole tab 013 is arranged at the second end, and the third pole tab 013 is connected to the first pole piece 151 or the second pole piece 152. The first output pole and the second output pole are arranged in the shell, the first output pole is electrically connected to the first pole tab, and the second output pole is electrically connected to the second pole tab.

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

[0127] It can be understood that the first pole piece 151 , the diaphragm 153 and the second pole piece 152 are stacked and wound in sequence to form the winding core 001 .

[0128] The first electrode piece 151 and the second electrode piece 152 include a coated area coated with an active material and an uncoated area uncoated with the active material. The first electrode tab 011, the second electrode tab 012, and the third electrode tab 013 can be integrally provided as at least a portion of the uncoated area. In other embodiments, the first electrode tab 011 can be separately welded to the first electrode piece 151, the second electrode tab 012 can be separately welded to the second electrode piece 152, and the third electrode tab 013 can be separately welded to either the first electrode piece 151 or the second electrode piece 152.

[0129] In addition, one of the first electrode piece 151 and the second electrode piece 152 is a positive electrode piece, and the other is a negative electrode piece. The polarity of the first electrode tab 011 is opposite to that of the second electrode tab 012, and the polarity of the third electrode tab 013 is the same as that of one of the first electrode tab 011 and the second electrode tab 012, but opposite to that of the other. For example, the first electrode piece 151 is a positive electrode piece, and the second electrode piece 152 is a negative electrode piece. Accordingly, the first electrode tab 011 is a positive electrode piece, and the second electrode tab 012 is a negative electrode piece. The third electrode tab 013 is connected to the first electrode piece 151 and is a positive electrode piece.

[0130] In the embodiment of the present application, a first electrode tab 011 and a second electrode tab 012 are provided at one end of the winding core 001 to collect current for the positive and negative electrodes, respectively. A third electrode tab 013 is provided at the other end of the winding core 001 to collect current for the positive or negative electrode. This increases the current collecting area of ​​the electrode connected to the third electrode tab 013, thereby increasing the number of electron conduction paths and improving the current collecting capacity of the electrode. This improves the current collecting capacity of the battery cell 003.

[0131] In addition, by providing the third pole tab 013 to increase the pole tab area of ​​the pole piece connected to the third pole tab 013 , its current carrying capacity can also be improved, thereby improving the current carrying capacity of the battery cell 003 .

[0132] See also Figure 4 or Figure 5 , Figure 4 is a structural diagram of the second end provided in an embodiment of the present application, Figure 5 In one embodiment, multiple layers of third tabs 013 are bent and stacked to form a third tab region 131 . The third tab region 131 extends along the circumference of the winding core body 015 in a closed or open ring shape.

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

[0134] The third tab area 131 may extend along the circumference of the winding core body 015 into a closed ring shape, such as Figure 4 As shown; the third tab area 131 can also extend along the circumference of the core body 015 into an open ring, that is, the third tab 013 extends along the circumference of the core body 015 into an arc segment. The arc segment can be one segment or multiple segments, and the multiple arc segments are arranged at intervals along the circumference of the core body 015, as shown. Figure 5 shown.

[0135] In this embodiment, by extending the third pole tab 013 along the circumferential direction of the winding core body 015, on the one hand, the connection length between the third pole tab 013 and the pole piece can be increased, thereby improving the connection strength between the third pole tab 013 and the pole piece, and further improving the structural reliability of the winding core 001; on the other hand, the area of ​​the third pole tab 013 can be increased, thereby improving the flow area of ​​the winding core 001, and further improving the current collecting capacity of the battery cell 003.

[0136] Among them, when the third pole ear area 131 extends into a closed ring along the circumference of the core body 015, the area of ​​the third pole ear 013 can be further increased, thereby increasing the current collecting area of ​​the pole piece connected to the third pole ear 013, so that the electron conduction path is increased, and the current collecting capacity of the pole piece can be improved.

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

[0138] See also Figure 4 In one embodiment, along the radial direction of the winding core 001 , from the center of the winding core body 015 outward, a first central hollow lug area 1541 and a third tab area 131 are sequentially provided at the second end.

[0139] The empty lug area is an area at the end of the winding core 001 where no lug is provided. Specifically, it is an area at the end of the winding core 001 that is not blocked by the lug after the lug is bent and stacked.

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

[0141] As can be understood, after the electrode sheet is wound into the core 001, the third electrode tab 013 is parallel to the axis of the core 001, occupying a large height dimension, which has a negative impact on the energy density of the battery cell. For this reason, the third electrode tab 013 is typically bent toward the center of the core 001 to reduce the height space occupied by the third electrode tab 013 in the battery cell. Directly bending the third electrode tab 013 would cause it to block the central hole 016 of the core 001.

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

[0143] In addition, the first central hollow area 1541 can also provide expansion space for the third electrode tab 013 that expands due to heat, so as to avoid the third electrode tab 013 from being staggered and subjected to greater stress after thermal expansion, thereby improving the reliability of the battery cell 003.

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

[0145] It can be understood that the inner diameter size C of the third pole ear area 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, through the above-mentioned limitation, on the one hand, it is possible to avoid the inner diameter C of the third pole tab area 131 being too small, which causes the third pole tab 013 to block the middle hole 016 of the winding core 001, thereby ensuring the smoothness of the electrolyte flowing into or out of the middle hole 016, and thus ensuring the wetting efficiency of the battery cell 003; on the other hand, it is possible to avoid the inner diameter C of the third pole tab area 131 being too large to affect the radial size of the third pole tab 013, thereby not only ensuring the current collecting area of ​​the third pole tab 013 to improve the current collecting capacity of the winding core 001, but also ensuring the welding area of ​​the third pole tab 013, and thus improving the welding stability between the third pole tab 013 and the collecting plate.

[0153] In addition, by limiting the minimum value of the inner diameter C of the third tab region 131 , the first central hollow tab region 1541 can have sufficient space to accommodate the third tab 013 that expands due to heat, thereby preventing the third tabs 013 from intertwining with each other and generating metal debris after thermal expansion.

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

[0155] It can be understood that, in combination with the above embodiments, optionally, along the radial direction of the core 001, from the center of the core body 015 to the outside, the second end is sequentially provided with a first central hollow ear area 1541, a third tab area 131 and a first peripheral hollow ear area 1544.

[0156] In this embodiment, by providing the first peripheral hollow ear area 1544, the third electrode ear 013 can be prevented from exceeding the outer periphery of the core body 015 after being flattened, thereby controlling the radial size of the core 001 to facilitate the core 001 to be put into the shell.

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

[0158] It can be understood that the outer diameter size D of the third tab area 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 includes 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, through the above-mentioned arrangement, on the one hand, the outer periphery of the third pole lug area 131 and the outer periphery of the core 001 can be arranged along the radial interval of the core 001, so that the bent third pole lug 013 can be located in the interval without exceeding the outer periphery of the core 001, thereby controlling the outer diameter of the core 001, which is conducive to the smooth insertion of the core 001 into the shell; on the other hand, it can avoid the outer periphery of the third pole lug area 131 and the outer periphery of the core 001 being too large to affect the area of ​​the third pole lug 013, so that the current collecting capacity and internal resistance of the third pole lug 013 can meet the requirements.

[0166] See also Figure 6 or Figure 7 , Figure 6 Schematic diagram of the projection relationship between the third tab 013 and the first tab 011 before bending provided in an embodiment of the present application. Figure 7Schematic diagram of the projection relationship between the third pole tab 013 and the second pole tab 012 before bending provided by an embodiment of the present application. In one embodiment, the third pole tab 013 is connected to the first pole piece 151. The plane perpendicular to the axis of the winding core body 015 is used as the projection plane, and the axial direction of the winding core body 015 is used as the projection direction. In the projection plane, the projection of the first pole tab 011 before bending and the projection of the third pole tab 013 before bending at least partially overlap, as shown in FIG. Figure 6 Alternatively, the third pole tab 013 is connected to the second pole piece 152, and the plane perpendicular to the axis of the winding core body 015 is used as the projection plane, and the axial direction of the winding core body 015 is used as the projection direction. In the projection plane, the projection of the second pole tab 012 before bending and the projection of the third pole tab 013 before bending at least partially overlap, as shown in FIG. Figure 7 shown.

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

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

[0169] In this embodiment, the above arrangement enables the third electrode tab 013 to have opposite locations along the axial direction of the winding core 001 as the first electrode tab 011 or the second electrode tab 012 connected to the same electrode sheet. This allows the third electrode tab 013 to collect current and then directly move along the axial direction of the winding core 001 to transfer current to the first electrode tab 011 or the second electrode tab 012 connected to the same electrode sheet, thereby shortening the current collection path of the winding core 001. This improves the current collection capacity of the battery cell 003.

[0170] See also Figure 8 , Figure 8 This is a schematic diagram of the structure of another winding core 001 provided in an embodiment of the present application. In one embodiment, winding core 001 further includes a fourth electrode tab 014. Fourth electrode tab 014 is disposed at the second end of winding core body 015. One of third electrode tab 013 and fourth electrode tab 014 is connected to first electrode piece 151, and the other is connected to second electrode piece 152.

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

[0172] Furthermore, 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, and the second electrode tab 012 is a negative electrode.

[0173] In this embodiment, by providing a first electrode tab 011 and a second electrode tab 012 at one end of the winding core 001 to collect current for the positive and negative electrodes, respectively, and providing a third electrode tab 013 and a fourth electrode tab 014 at the other end of the winding core 001 to collect current for the positive and negative electrodes, respectively, the current collecting area of ​​the two electrode sheets of the winding core 001 can be increased, thereby increasing the number of electron conduction paths and improving the current collecting capacity of the first electrode sheet 151 and the second electrode sheet 152. In this way, the current collecting capacity of the battery cell 003 can be further improved.

[0174] See also Figure 9 , Figure 9 This is a schematic diagram of the structure of another second end provided by an embodiment of the present 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 the fourth tab region 141, the first mid-ring hollow tab region 1547, and the third tab region 131. The fourth tab region 141 and the third tab region 131 each extend along the circumference of the core body 015 in a closed or open annular shape.

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

[0176] The third electrode tab 013 and the fourth electrode tab 014 can be insulated and isolated spatially by the first middle ring hollow tab area 1547 , or an insulating member can be provided between the third electrode tab 013 and the fourth electrode tab 014 to achieve insulation and isolation.

[0177] In this embodiment, by extending the third pole tab 013 and the fourth pole tab 014 along the circumferential direction of the winding core body 015, on the one hand, the connection length between the third pole tab 013 and the fourth pole tab 014 and the pole piece can be increased, thereby improving the connection strength between the third pole tab 013 and the fourth pole tab 014 and the pole piece, thereby improving the structural reliability of the winding core 001; on the other hand, the area of ​​the third pole tab 013 and the fourth pole tab 014 can be increased respectively, thereby improving the flow area of ​​the winding core 001, thereby improving the flow capacity of the battery cell 003.

[0178] In addition, by providing the first mid-ring hollow ear area 1547, a gap can be created between the third pole ear 013 and the fourth pole ear 014 to provide expansion space for the third pole ear 013 and the fourth pole ear 014 that expand due to heat, thereby avoiding excessive pressure between the third pole ear 013 and the fourth pole ear 014 due to thermal expansion, thereby ensuring the reliability of insulation between the third pole ear 013 and the fourth pole ear 014.

[0179] See also 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, the second end is sequentially provided with a third central hollow tab region 1543, a fourth tab region 141, and a third tab region 131. The fourth tab region 141 and the third tab region 131 each extend along the circumference of the core body 015 in a closed or open annular shape.

[0180] In this embodiment, by setting the third central hollow ear area 1543, the fourth pole ear 014 can be prevented from blocking the middle hole of the winding core 001, thereby improving the smoothness of the electrolyte flowing out of or into the middle hole of the winding core 001, thereby ensuring the wetting efficiency of the battery cell 003.

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

[0182] It can be understood that the inner diameter size J of the third pole ear area 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 24 mm, J includes but is not limited to 0.72 mm, 0.86 mm, 1.08 mm, 1.65 mm, 2.13 mm, 2.95 mm, 3.11 mm, 3.71 mm, 4.23 mm, 5.25 mm, 5.78 mm, and 5.82 mm;

[0185] When A is 30 mm, J includes but is not limited to 0.9 mm, 1.06 mm, 2.78 mm, 3.13 mm, 3.85 mm, 4.19 mm, 5.21 mm, 6.23 mm, 6.25 mm, 6.38 mm, 6.59 mm, and 6.6 mm;

[0186] When A is 35 mm, J includes but is not limited to 1.05 mm, 2.06 mm, 3.78 mm, 4.13 mm, 4.85 mm, 5.19 mm, 5.21 mm, 6.23 mm, 7.25 mm, 7.38 mm, 7.59 mm, and 7.7 mm;

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

[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, through the above-mentioned limitation, on the one hand, it is possible to avoid the inner diameter J of the fourth pole tab area 141 being too small, which causes the fourth pole tab 014 to block the middle hole 016 of the winding core 001, thereby ensuring the smoothness of the electrolyte flowing into or out of the middle hole 016, and thus ensuring the wetting efficiency of the battery cell 003; on the other hand, it is possible to avoid the inner diameter J of the fourth pole tab area 141 being too large to affect the radial size of the fourth pole tab 014, thereby not only ensuring the current collecting area of ​​the fourth pole tab 014 to improve the current collecting capacity of the winding core 001, but also ensuring the welding area of ​​the fourth pole tab 014, and thus improving the welding stability between the fourth pole tab 014 and the collecting 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 crossing the third central hollow region 1543 after bending and generating metal debris.

[0191] See also 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, the second end is sequentially provided with the fourth tab region 141, the third tab region 131, and the third peripheral hollow tab region 1546. The fourth tab region 141 and the third tab region 131 each extend along the circumference of the core body 015 in a closed or open annular shape.

[0192] It can be understood that, in combination with the above-mentioned embodiments, optionally, along the radial direction of the core 001, from the center of the core body 015 to the outside, the second end is sequentially provided with a third central hollow ear area 1543, a fourth pole ear area 141, a first middle ring hollow ear area 1547, a third pole ear area 131 and a third peripheral hollow ear area 1546.

[0193] In this embodiment, by providing the third peripheral hollow ear area 1546, after the third electrode ear 013 is flattened, the third electrode ear 013 can be prevented from exceeding the outer periphery of the core body 015, thereby controlling the radial size of the core 001 to facilitate the core 001 to be put into the shell.

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

[0195] It can be understood that the outer diameter size D of the third tab area 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 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 23.5mm;

[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, and 44.59mm.

[0200] In this embodiment, through the above-mentioned arrangement, on the one hand, the outer periphery of the third pole lug area 131 and the outer periphery of the core 001 can be arranged along the radial interval of the core 001, so that the bent third pole lug 013 can be located in the interval without exceeding the outer periphery of the core 001, thereby controlling the outer diameter of the core 001, which is conducive to the smooth insertion of the core 001 into the shell; on the other hand, it can avoid the outer periphery of the third pole lug area 131 and the outer periphery of the core 001 being too large to affect the area of ​​the third pole lug 013, so that the current collecting capacity and internal resistance of the third pole lug 013 can meet the requirements.

[0201] See also Figure 9 In one embodiment, the outer diameter of the winding core body 015 is A, the outer diameter of the fourth tab region 141 is I, and the following conditions are satisfied: 25%A≤I≤35%A; and / or the inner diameter of the third tab region 131 is C, and the following conditions are satisfied: 40%A≤C≤75%A.

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

[0203] Among them, the outer diameter size I of the fourth pole ear area 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 24 mm, I includes but is not limited to 6 mm, 6.06 mm, 6.2 mm, 6.5 mm, 6.95 mm, 7.11 mm, 7.21 mm, 7.3 mm, 7.5 mm, 7.8 mm, 8.02 mm, and 8.4 mm;

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

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

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

[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 tab 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 size I of the fourth pole lug area 141, it is possible to avoid the outer diameter size of the fourth pole lug area 141 being too large and affecting the arrangement of the third pole lug area 131; by limiting the inner diameter size C of the third pole lug area 131, it is possible to avoid the inner diameter size being too small and affecting the arrangement of the fourth pole lug 014; and by limiting the outer diameter size I of the fourth pole lug area 141 and the inner diameter size C of the third pole lug area 131, it is possible to ensure that there is a sufficient spacing between the fourth pole lug 014 and the third pole lug 013, so that the fourth pole lug 014 and the third pole lug are insulated and isolated by the spacing, or an insulating member is provided in the spacing.

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

[0219] See also Figure 5 In one embodiment, the third electrode tab 013 is connected to the first electrode piece 151 .

[0220] Taking the plane perpendicular to the axis of the core body 015 as the projection plane and the axial direction of the core body 015 as the projection direction, in the projection plane, the projection of the first electrode tab 011 before bending partially overlaps with the projection of the third electrode tab 013 before bending.

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

[0222] In this embodiment, the above arrangement allows the third tab 013 and the first tab 011 to have opposing portions along the axial direction of the winding core 001. This allows the third tab 013 to collect current and then directly move along the axial direction of the winding core 001 to transfer current to the first tab 011, thereby shortening the current collection path of the winding core 001. This improves the current collection capacity of the battery cell 003.

[0223] See also Figure 10 , Figure 10 15. FIG. 15 shows the projection relationship between the fourth electrode tab 014 and the second electrode tab 012 before bending according to an embodiment of the present application. In one embodiment, the fourth electrode tab 014 is connected to the second electrode piece 152.

[0224] Taking the plane perpendicular to the axis of the core body 015 as the projection plane and the axial direction 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 fourth electrode tab 014 before bending at least partially overlap.

[0225] It can be understood that the projection of the root of the second electrode tab 012 partially overlaps with the projection of the root of the fourth electrode tab 014 .

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

[0227] In this embodiment, the above arrangement allows the fourth tab 014 and the second tab 012 to have opposing portions along the axial direction of the winding core 001. This allows the fourth tab 014 to collect current and then 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 of the winding core 001. This improves the current collection capacity of the battery cell 003.

[0228] See also Figure 11 , Figure 11 This is a schematic diagram of the structure of the first end provided by an embodiment of the present 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 the first tab region 111, the second mid-ring hollow tab region 1548, and the second tab region 121. The first tab region 111 and the second tab region 121 each extend along the circumference of the core 001 in a closed or open annular shape.

[0229] The first tab region 111 and the second tab region 121 may extend along the circumference of the winding core body 015 to form a closed ring. Figure 11 As shown, the first tab region 111 and the second tab region 121 may also extend in an open ring shape along the circumference of the core body 015. That is, the first tab region 111 and the second tab region 121 may extend in an arc segment along the circumference of the core body 015. The arc segment may be one segment or multiple segments, and the multiple arc segments are spaced apart along the circumference of the core body 015.

[0230] In this embodiment, by extending the first pole lug area 111 and the second pole lug area 121 along the circumferential direction of the winding core body 015, not only the connection length between the first pole lug 011 and the first pole piece 151 and the connection length between the second pole lug 012 and the second pole piece 152 can be increased to improve the positional stability of the first pole lug 011 and the second pole lug 012; the area of ​​the first pole lug 011 and the second pole lug 012 can also be increased, thereby improving the current collecting capacity of the first pole lug 011 and the second pole lug 012, and further improving the current collecting capacity of the battery cell 003.

[0231] See also 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 winding core 015, from the center of the winding core 015 outward, the first end is sequentially provided with a second central hollow tab region 1542, the first tab region 111, and the second tab region 121.

[0232] In this embodiment, by providing the second central hollow ear area 1542, the first pole 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 further ensuring the wetting efficiency of the battery cell 003.

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

[0234] It can be understood that the inner diameter size M of the third pole ear area 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 24 mm, M includes but is not limited to 0.72 mm, 0.86 mm, 1.08 mm, 1.65 mm, 2.13 mm, 2.95 mm, 3.11 mm, 3.71 mm, 4.23 mm, 5.25 mm, 5.78 mm, and 5.82 mm;

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

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

[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, through the above-mentioned limitation, on the one hand, it is possible to avoid the inner diameter M of the first pole lug area 111 being too small, which causes the first pole lug 011 to block the middle hole 016 of the winding core 001, thereby ensuring the smoothness of the electrolyte flowing into or out of the middle hole 016, and thus ensuring the infiltration efficiency of the winding core 001; on the other hand, it is possible to avoid the inner diameter M of the first pole lug area 111 being too large to affect the radial size of the first pole lug 011, thereby not only ensuring the current collecting area of ​​the first pole lug 011 to improve the current collecting capacity of the winding core 001, but also ensuring the welding area of ​​the first pole lug 011, and thus improving the welding stability between the first pole lug 011 and the collecting plate.

[0242] In addition, by limiting the minimum value of the inner diameter M of the first tab area 111, the second central hollow tab area 1542 can have sufficient space to accommodate the first tab 011 that expands due to heat, thereby preventing the first tab 011 from interlacing in the second central hollow tab area 1542 after thermal expansion and generating metal debris.

[0243] See also 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 winding core 015, from the center of the winding core 015 outward, the first end is sequentially provided with the first tab region 111, the second tab region 121, and the second peripheral hollow tab region 1545.

[0244] In combination with the above-mentioned embodiment, optionally, along the radial direction of the core 001, from the center of the core body 015 to the outside, the second end is sequentially provided with a second central hollow ear area 1542, a first pole ear area 111, a second middle ring hollow ear area 1548, a second pole ear area 121 and a second peripheral hollow ear area 1545.

[0245] In this embodiment, by providing the second peripheral hollow ear area 1545, the second electrode ear 012 can be prevented from exceeding the outer periphery of the core body 015 after the second electrode ear 012 is flattened, thereby controlling the radial size of the core 001 to facilitate the core 001 to be put into the shell.

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

[0247] It can be understood that the outer diameter size E of the second tab area 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, and 44.59mm.

[0252] In this embodiment, through the above-mentioned arrangement, on the one hand, the outer periphery of the second pole lug area 121 and the outer periphery of the core 001 can be arranged at a radial interval along the core 001, so that the bent second pole lug 012 can be located in the interval without exceeding the outer periphery of the core 001, thereby controlling the outer diameter of the core 001, which is conducive to the smooth insertion of the core 001 into the shell; on the other hand, it can avoid the outer periphery of the second pole lug area 121 and the outer periphery of the core 001 being too large to affect the area of ​​the second pole lug 012, so that the current collecting capacity and internal resistance of the second pole lug 012 can meet the requirements.

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

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

[0255] Among them, the outer diameter size G of the first pole ear area 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 size F of the second tab area 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 size G of the first pole lug area 111, it is possible to avoid the outer diameter size of the first pole lug area 111 being too large and affecting the arrangement of the second pole lug area 121; by limiting the inner diameter size F of the second pole lug area 121, it is possible to avoid the inner diameter size being too small and affecting the arrangement of the first pole lug 011; and by limiting the outer diameter size G of the first pole lug area 111 and the inner diameter size F of the second pole lug area 121, it is possible to ensure that there is a sufficient spacing between the first pole lug 011 and the second pole lug 012, so that the first pole lug 011 and the second pole lug are insulated and isolated by the spacing, or an insulating member is provided in the spacing.

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

[0271] Optionally, the third electrode tab 013 is connected to the first electrode piece 151, and the inner diameter C of the third electrode tab region 131 is no greater than the outer diameter G of the first electrode tab region 111. Thus, after collecting current, the third electrode tab 013 can directly move along the axial direction of the winding core 001 to transfer current to the first electrode tab 011, thereby shortening the current collection path and enhancing the current collection effect.

[0272] Similarly, the fourth electrode tab 014 is connected to the second electrode piece 152, and the inner diameter F of the second electrode tab region 121 is no greater than the outer diameter I of the fourth electrode tab region 141. As a result, after collecting current, the fourth electrode tab 014 can directly move along the axial direction of the winding core 001 to transfer current to the second electrode tab 012, thereby shortening the current collection path and enhancing the current collection effect.

[0273] In one embodiment, FG ≥ 4 mm.

[0274] Illustratively, 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 4 mm, 4.1 mm, 4.3 mm, 4.4 mm, 4.5 mm, 4.6 mm, 4.8 mm, and 5 mm.

[0275] In this embodiment, through the above-mentioned limitation, there can be at least a 4 mm gap between the inner diameter F of the second pole tab area 121 and the outer diameter G of the first pole tab area 111, so that the first pole tab 011 and the second pole tab can be insulated and isolated through this gap, or the gap can have enough space to set the insulating part, so as to improve the convenience of configuring the insulating part.

[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 ≥ 4 mm.

[0277] Illustratively, 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 4 mm, 4.1 mm, 4.3 mm, 4.4 mm, 4.5 mm, 4.6 mm, 4.8 mm, and 5 mm.

[0278] In this embodiment, through the above-mentioned limitation, the second pole tab 012 can have a sufficient area, which not only enables the current collecting capacity of the second pole tab 012 to meet the current collecting requirements of the winding core 001, but also enables the second pole tab 012 to have a suitable welding area, thereby improving the operability of the welding connection between the second pole tab 012 and the collecting plate.

[0279] The technical solutions and technical effects of the present application are described in detail below through specific embodiments. The following embodiments are only some embodiments of the present application and do not specifically limit the present application.

[0280] This example aims to investigate the effect of applying the winding core to a battery on battery performance.

[0281] The test contents of the embodiment are described as follows:

[0282] 1. Test related instructions

[0283] The following test method is a DCR test, that is, a Direct Current Resistance test.

[0284] The equipment used for the test is a power battery tester, and its model may be: CTE-8008-5V200A.

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

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

[0287] First, take 1C=32.4A as the nominal capacity, 1 / 3C, i.e. 10.8Ah as the standard charge and discharge capacity, and the average value of the actual capacitance measured after 3 cycles of charge and discharge as the calibration capacity C0, where:

[0288] C0=(∑In*Tn+∑I'n*T'n) / 6,

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

[0290] In is the nth charging current;

[0291] Tn is the nth charging time;

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

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

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

[0295] Next, when the state of charge of the cell is 50% SOC, discharge it at a constant current of 2C0 for 30 seconds, record the voltage change difference δU discharge and the discharge current value I discharge before and after discharge, and according to the formula: DCR discharge = δU discharge / I discharge, the battery charging DCR at the state of charge of the cell of 50% SOC is obtained;

[0296] At the same time, when the state of charge of the battery cell is 50% SOC, it is charged at a constant current of 2C0 for 30s, and the voltage change difference before and after charging δUcharging and the charging current value Icharging are recorded; and according to the formula: DCRcharging = δUcharging / Icharging, the battery discharge DCR when the state of charge of the battery cell is 50% SOC is obtained.

[0297] 2. Test Results

[0298] The test results are all based on a battery cell with a core outer diameter A of 45.1mm, a core middle hole diameter of 5mm, a core height of 88.3±0.3mm, and an axial dimension of 4-5mm before the tab is bent.

[0299] 2.1 Setting up a control group

[0300] The control group is a battery cell with only positive and negative tabs on the first end in the related art. The test data is as follows:

[0301]

[0302] Table 1. Parameters and test 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 winding core. The area of ​​the positive tab is 1002.4 mm2, and the area of ​​the negative tab is 1067.6 mm2. When the state of charge of the battery cell is 50% SOC, the battery charging DCR is 3.72 mΩ and the battery discharging DCR is 3.69 mΩ.

[0305] (2) In control group 2, the positive tab is set at the same end of the winding core. When the positive tab area is 235 mm2 and the negative tab area 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 battery cell is 50%.

[0306] 2.2 Based on the control group, the single variable method was used to change the parameter setting examples of the winding core. The parameter change tables and test results of each example are shown in Tables 2 to 4.

[0307] 2.21 Under the premise that the rest of the structure is the same, a third pole tab is added at the second end of the winding core, and the third pole tab is the positive pole tab.

[0308] According to the formulas: 3% A ≤ C ≤ 30% A and 65% A ≤ D ≤ 80% A, the inner and outer diameter ranges for the third tab region formed by the bent and stacked positive tabs are: 1.353mm ≤ C ≤ 13.53mm for the inner diameter C of the positive tab, and 29.315mm ≤ D ≤ 36.08mm for the outer diameter D of the positive tab. The area of ​​the negative tab remains unchanged, and the total areas of the positive tabs are 1002.4mm² and 999.9mm², respectively. Correspondingly, C is set to 3mm and 13.5mm, and D is set to 31.4mm and 34mm, respectively.

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

[0310]

[0311] Table 2. Parameters and test results of the bottom-mounted positive electrode

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

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

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

[0315] (2) The total area of ​​the negative tabs of Example 2 is equal to that of the negative tabs of Control 1, both being 1067.6 mm2. The total area of ​​the positive tabs of Example 2 is 999.9 mm2, which is lower than the total area of ​​the positive tabs of Control 1 (1002.4 mm2). However, the battery charge DCR of Example 2 is 3.51 mΩ, which is lower than the battery charge DCR of Control 1 (3.72 mΩ). Furthermore, the battery discharge DCR of Example 2 is 3.64 mΩ, which is lower than the battery discharge DCR of Control 1 (3.68 mΩ).

[0316] Therefore, under the premise that the total area of ​​the negative tabs is equal, the positive tabs are respectively arranged at both ends of the winding core. Compared with the case where the positive tabs are only arranged at one end of the winding core, even if the total area of ​​the positive tabs of the former is slightly lower than that of the latter, the battery charging DCR can still be reduced and the battery discharging DCR can be reduced, thereby improving the overcurrent capacity.

[0317] (3) According to the comparison between Example 1 or Example 2 and Control Group 2, it can be seen that, under the premise that the areas of the positive and negative tabs arranged at the first end of the winding core are equal, the positive tab is arranged at the second end of the winding core to increase the total area of ​​the positive tab, which can reduce the battery charging DCR and help reduce the battery discharging DCR, thereby improving the current capacity;

[0318] (4) According to the comparison between 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 charge DCR and the battery discharge DCR, thereby improving the overcurrent capacity.

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

[0320]

[0321] Table 3. Parameters and test results of the bottom-mounted positive electrode

[0322] It can be seen from Table 3 that, under the premise that the areas of the positive and negative tabs at the first end remain 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 is increased, which can reduce the battery charging DCR and help reduce the battery discharging DCR, thereby improving the overcurrent capacity.

[0324] 2.23 Based on the above embodiment, a fourth electrode tab is added at 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 successively.

[0325] According to the formulas: 40% A ≤ C ≤ 75% A and 85% A ≤ D < 100% A, the inner and outer diameter ranges of the third tab region formed by the stacked positive tabs are: positive tab inner diameter C: 18.4mm ≤ C ≤ 33.825mm, positive tab outer diameter D: 38.353mm ≤ D < 45.1mm. The values ​​for C are 33mm, 28mm, 25mm, and 22.5mm, and the values ​​for D are 45mm, 42mm, 40mm, and 38.5mm, respectively.

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

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

[0328]

[0329]

[0330] Table 4. Parameters and test results of the bottom-mounted negative electrode

[0331] According to Table 4, the following conclusions can be drawn:

[0332] By comparing Example 6, Example 7, Example 8 and Example 9, it can be seen 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 tabs at the second end are equal, when the area of ​​the negative tab at the second end increases 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 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; accordingly, the battery charge DCR decreases 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 is increased, thereby reducing the battery discharge DCR and helping to reduce the battery charge DCR, thereby improving the overcurrent capability.

[0334] In related technologies, to achieve output on the same side of the cell, the cell cover serves as one output pole, and the pole extends through the cover and serves as the other output pole (with an insulating member provided between the pole and the cover). The pole is electrically connected to a pole piece of one polarity, and the cover is electrically connected to a pole piece of the other polarity. When the air pressure inside the cell changes, the cell cover is easily deformed by the force and separated from the pole piece. This can result in the cell not being able to output normally when in normal operating conditions.

[0335] In view of this, the embodiment of the present application also provides a battery cell; Figures 12 to 16 Describe the battery cells in detail.

[0336] In one embodiment, the first output pole is a pole assembly 107. The second output pole is a cover body 108. The cover body 108 is assembled with the housing 031 to enclose the receiving cavity. The pole assembly 107 is mounted on the cover body 108 and electrically connected to the first pole tab 011. The cover body 108 is provided with a recessed portion 109, which is electrically connected to the second pole tab 012.

[0337] Among them, the recessed portion 109 is electrically connected to the second pole piece 152, so that the cover body 108 is connected to the winding core 001, so that the cover body 108 serves as an output pole of one polarity; and the pole assembly 107 is electrically connected to the first pole piece 151, so that the pole group serves as an output pole of another polarity.

[0338] In this embodiment, the recessed portion 109 is provided on the cover body 108 to increase the surface area of ​​the cover body 108. When the cover body 108 is subjected to pressure, the recessed portion 109 can absorb and disperse some of the pressure, thereby improving the impact resistance of the cover body 108. This improves the deformation resistance of the cover body 108, preventing deformation of the cover body 108 under stress, thereby preventing separation of the cover body 108 from the second electrode sheet 152, and enabling normal output of the battery cell 003.

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

[0340] It should be noted that when the pressure inside the battery cell 003 is too high to prevent the battery cell 003 shell from rupturing, the explosion-proof valve configured on the battery cell 003 opens or the explosion-proof notch breaks, so that the excessive pressure of the gas inside the battery cell 003 can be released through the explosion-proof valve or the broken explosion-proof notch.

[0341] In addition, 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 body 108 serves as the negative output terminal and the pole assembly 107 serves as the positive output terminal.

[0342] In one embodiment, see Figure 1 and Figure 13 The recessed portion 109 is provided with a welding plate 116 for welding connection. The welding plate 116 is electrically connected to the second tab 012. More specifically, considering the difficulty of welding, the thickness of the welding plate 116 is less than the thickness of the region of the cover plate body 108 where the recessed portion 109 is not provided. This configuration reduces the thickness of the welding plate 116, allowing welding energy to more easily penetrate the welding plate 116 during the welding process, thereby reducing the difficulty of welding.

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

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

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

[0346] Also, see Figure 15The winding core 001 further includes a second current collector 111a, which is disposed between the first electrode piece 151 and the electrode assembly 107. The second current collector 111a is electrically connected to the first electrode piece 151 and the electrode assembly 107. Furthermore, to ensure connection strength, the second current collector 111a is welded to the first electrode piece 151, and the second current collector 111a is welded to the electrode 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 electrodes of the battery cell 003 are located on the same side of the winding core 001, facilitating current collection from one side of the battery cell 003. This reduces the length of the wiring between one electrode and other electrical components, compared to a structure with positive and negative electrodes output from both sides, thereby reducing line resistance. This improves the current collection capacity of the battery cell 003.

[0348] In some embodiments, see Figure 14 The thickness of welding plate 116 is H1, and the thickness of first current collecting member 110 is H2. H2 = bH1, satisfying the following: 0.5 ≤ b ≤ 1.2. Specifically, if welding plate 116 is too thick, welding becomes more difficult. If welding plate 116 is too thin, cover plate body 108 will be insufficiently strong and easily deformed under stress. A thin first current collecting member 110 is too thin, resulting in insufficient strength and prone to breakage during use. A thicker first current collecting member 110 increases resistance and the space occupied by first current collecting member 110. Welding plate 116 is welded to first current collecting member 110. It should be noted that when b is less than 0.5, the thickness of first current collecting member 110 and welding plate 116 is too small, resulting in reduced strength and prone to breakage during use. When b is greater than 1.2, the thickness of first current collecting member 110 and welding plate 116 is too thick, increasing resistance, occupying more space, and making welding more difficult. More specifically, in this embodiment, the thickness of the welding plate 116 is 0.2-0.7 mm.

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

[0350] It should be noted that the formation method of the recessed portion 109 is not limited. In this embodiment, the recessed portion 109 includes a groove. Specifically, the cover body 108 is placed on a stamping machine, and a groove is punched out on the cover body 108 by stamping. During the stamping process, due to the effect of 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 body 108. It should be noted that the groove includes a bottom plate 112 and a side plate 113, and the welding plate 116 can be either the bottom plate 112 or the side plate 113, and can be selected according to actual conditions. Taking into account the difficulty of welding and the stability of the structure, the welding plate 116 is preferably the bottom plate 112.

[0351] In some embodiments, see Figure 14 , the thickness of the welding plate 116 is H1, the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is H, 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 body 108 is easily broken at the recessed portion 109. When a is greater than 0.7, the thickness of the welding plate 116 is relatively thick, and the difficulty of welding increases. In this embodiment, the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is 0.4~1mm. According to the above relationship, it can be inferred that the thickness of the welding plate 116 is 0.2~0.7mm.

[0352] Illustratively, the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided may 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, or 1 mm.

[0353] Illustratively, 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 region of the cover body 108 where the recessed portion 109 is not provided is 0.4 mm, the thickness of the welding plate 116 may be 0.2 mm, 0.208 mm, 0.216 mm, 0.22 mm, 0.224 mm, 0.232 mm, 0.24 mm, 0.248 mm, 0.256 mm, 0.26 mm, 0.264 mm, 0.272 mm, or 0.28 mm. When the thickness of the region of the cover body 108 where the recessed portion 109 is not provided 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, and 0.42 mm. When the thickness of the region of the cover body 108 where the recessed portion 109 is not provided 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, and 0.7 mm.

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

[0355] It can be understood that compared with setting the welding plate 116 on the peripheral side wall of the recess, setting the welding plate 116 on the bottom plate 112 can make the welding plate 116 more flat, thereby improving the ease of welding the welding plate 116 to components such as the pole ear or the collecting plate, and further improving the reliability of welding the welding plate 116 to the corresponding components.

[0356] In some embodiments, see Figure 15 The recessed portion 109 also includes a side plate 113 connected to the bottom plate 112 to form a recess together with the bottom plate 112. The bottom plate 112 is electrically connected to the second pole piece 152. The bottom 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 bottom plate 112, that is, the entire bottom plate 112 is welded to the first current collecting member 110, and the welding portion can be a partial area in the bottom plate 112, that is, part of the bottom plate 112 is welded to the first current collecting member 110.

[0357] Among them, the thickness of the welding plate 116 is H1, the thickness of the side plate 113 is H4, cH4=H1, and satisfies: 0.3≤c≤0.6. It should be noted that when c is less than 0.3, the thickness of the side plate 113 is thin and is prone to breakage during use. When c is greater than 0.6, the thickness of the side plate 113 increases and the space occupied increases. When the thickness of the welding plate 116 is 0.2mm, the thickness of the side plate 113 is 0.67mm, 0.571mm, 0.5mm, 0.44mm, 0.4mm, 0.364mm, and 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, and 0.84mm. When the thickness of the welding plate 116 is 0.7 mm, the thickness of the side plate 113 may be 2.34 mm, 2 mm, 1.75 mm, 1.56 mm, 1.4 mm, 1.273 mm, or 1.167 mm.

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

[0359] Among them, see Figure 14 and Figure 15, the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is H, and the curvature radius of the first bent connection portion 117 is R1, wherein R1=mH, satisfying: 0.8≤m≤2. It should be noted that when m is less than 0.8, the curvature radius of the first bent portion is small, and the effect of dispersing the force cannot be achieved. When m is greater than 2, the curvature radius of the first bent connection portion 117 is large, resulting in an increase in the overall size of the cover body 108 and an increase in the occupied space. Specifically, the curvature radius of the first bent connection 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, 2H. When the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is 0.4 mm, the curvature radius of the first bent connection portion 117 is 0.32 mm, 0.328 mm, 0.336 mm, 0.34 mm, 0.352 mm, 0.36 mm, 0.368 mm, 0.376 mm, 0.38 mm, 0.384 mm, 0.4 mm, 0.48 mm, 0.56 mm, 0.6 mm, 0.64 mm, 0.72 mm, and 0.8 mm. When the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is 0.6 mm, the curvature radius of the first bent connection portion 117 is 0.48 mm, 0.492 mm, 0.504 mm, 0.51 mm, 0.528 mm, 0.54 mm, 0.552 mm, 0.564 mm, 0.57 mm, 0.576 mm, 0.588 mm, 0.6 mm, 0.66 mm, 0.72 mm, 0.84 mm, 0.9 mm, 0.96 mm, 1.08 mm, and 1.2 mm. When the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is 1 mm, the curvature radius of the first bent connection portion 117 is 0.8 mm, 0.82 mm, 0.84 mm, 0.85 mm, 0.88 mm, 0.9 mm, 0.92 mm, 0.94 mm, 0.95 mm, 0.96 mm, 1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.8 mm, and 2 mm.

[0360] See also Figure 14 and Figure 15The radius of curvature of the second bent connection portion 118 is R2, where R2 = nH, satisfying the following: 0.1 ≤ n ≤ 1. Specifically, the radius of curvature of the second bent connection 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 region of the cover body 108 where the recessed portion 109 is not provided is 0.4mm, the radius of curvature of the second bent connection 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 region of the cover body 108 without the recessed portion 109 is 0.6 mm, the curvature radius of the second bent connection portion 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 region of the cover body 108 without the recessed portion 109 is 1 mm, the curvature radius of the second bent connection portion 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 region of the cover body 108 where the recessed portion 109 is not provided is 0.4 mm, the radius of curvature of the first bent connection portion 117 is 0.32 mm, and the radius of curvature of the second bent connection portion 118 is 0.16 mm, p is 0.5, which meets the requirements of the above formula.

[0362] In some embodiments, the recessed portion 109 includes a first bent portion 117, which connects between the side panel 113 and the bottom panel 112. The thickness of the first bent portion 117 gradually decreases along the direction from the side panel 113 to the bottom panel 112. This configuration makes the connection between the side panel 113 and the cover body 108 in the area where the recessed portion 109 is not provided smoother.

[0363] In some embodiments, see Figure 14, the thickness of the area of ​​the cover body 108 where the recess 109 is not provided 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 (that is, the size excluding the bend). When d is less than 2.5, the overall width of the recess 109 is small, the width of the welding plate 116 is correspondingly reduced, the welding area between the welding plate 116 and the first current collecting part 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, 5H. When the thickness of the region of the cover body 108 where the recessed portion 109 is not provided is 0.4 mm, the width of the recessed portion 109 may 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 region of the cover body 108 where the recessed portion 109 is not provided is 0.6 mm, the width of the recessed portion 109 may 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 body 108 where the recess 109 is not provided is 1 mm, the width of the recess 109 can be 2.5 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, or 5 mm.

[0364] Also, see Figure 14, the depth of the recessed portion 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 recessed portion 109 is too shallow and the deformation resistance is weak. When the air pressure inside the battery cell 003 increases, the cover body 108 is easily separated from the first current collecting member 110. When e is greater than 3.5, the depth of the recessed portion 109 is too deep, resulting in an increase in the overall size of the battery cell 003 and an increase in the occupied space. Specifically, the depth of the recessed portion 109 can be 1.5H, 1.8H, 2H, 2.2H, 2.5H, 2.8H, 3H, 3.1H, 3.2H, 3.5H. When the thickness of the area of ​​the cover body 108 where the recessed portion 109 is not provided is 0.4 mm, the depth of the recessed portion 109 may 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 body 108 where the recessed portion 109 is not provided is 0.6 mm, the depth of the recessed portion 109 may 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 body 108 where the recess 109 is not provided is 1 mm, the depth of the recess 109 may be 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.1 mm, 3.2 mm, or 3.5 mm.

[0365] In one embodiment, see Figure 13 In order to facilitate welding of the welding plate 116 and the first current collecting member 110 , the recessed portion 109 protrudes toward the accommodating cavity 311 , while also shortening the distance between the cover body 108 and the winding core 001 , further preventing the second pole piece 152 from separating from the cover body 108 .

[0366] Furthermore, by protruding the recessed portion 109 toward the accommodating cavity 311, the pressure-bearing area of ​​the cover body 108 is increased. Thus, when the cover body 108 is subjected to pressure, the recessed portion 109 can partially absorb the pressure exerted on the cover body 108. This improves the deformation resistance of the cover body 108 and prevents deformation of the cover body 108 under stress.

[0367] In some embodiments, see Figure 13 and Figure 16The diameter of the circle encompassing the outer contour of the orthographic projection of the housing 031 on the horizontal plane is D1, and the diameter of the circle encompassing the centerline of the orthographic projection of the recess 109 on the horizontal plane is D2, where D2 = fD1, satisfying the following: 0.5 ≤ f ≤ 0.8. It should be noted that when f is less than 0.5, the recess 109 is positioned closer to the terminal assembly 107 (i.e., the overall position is biased inward), resulting in a corresponding reduction in the volume of the second current collector 111a and a decrease in the current collecting capacity of the battery cell 003. When f is greater than 0.8, the recess 109 is positioned closer to the sidewall of the housing 031 (i.e., the overall position is biased outward). Due to the welded connection between the recess 109 and the first current collector 110, the volume of the first current collector 110 is correspondingly smaller, and the current collecting capacity of the battery cell 003 is also reduced. Specifically, in this embodiment, the diameter of the circle encompassing the outer contour of the orthographic projection of the housing 031 on the horizontal plane is 24 to 60 mm. The diameter of the circle on which the centerline of the orthographic projection of the recessed portion 109 lies on the horizontal plane is 0.5D1, 0.55D1, 0.6D1, 0.65D1, 0.7D1, 0.75D1, or 0.8D1. When D1 is 24 mm, D2 can be 12 mm, 13.2 mm, 14.4 mm, 15.6 mm, 16.8 mm, 18 mm, or 19.2 mm. When D1 is 40 mm, D2 can be 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, 30 mm, or 32 mm. When D1 is 60 mm, D2 can be 30 mm, 33 mm, 36 mm, 39 mm, 42 mm, 45 mm, or 48 mm.

[0368] It should be noted that the cross-sectional shape of the recessed portion 109 is not limited, as long as it can protrude toward the accommodating cavity 311 . For example, the cross-sectional shape of the recessed portion 109 can be U-shaped, V-shaped, or W-shaped.

[0369] In one embodiment, see Figure 15 To prevent short circuits within the battery cell 003, a first insulating member 117a is further 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 from the second current collector 111a, preventing contact between the two. Furthermore, the first insulating member 117a is disposed below the cover body 108 to provide support therefor.

[0370] In the related art, the battery cell includes a cover plate assembly, a shell and a winding core arranged in the shell, and the cover plate assembly includes a cover plate body and a pole assembly. The cover plate body covers and seals the shell. The pole assembly is passed through the cover plate body. The battery cell generates heat during operation, causing the temperature of the battery cell to rise. As the temperature of the battery cell continues to rise, and accompanied by the chemical reaction of charging and discharging of the battery cell, the electrolyte inside the battery cell will produce gas. When there is too much gas inside the battery cell and it cannot be discharged smoothly, the pressure inside the battery cell will increase. When excessive pressure presses against the cover plate body, it will cause the cover plate body to deform and the connection strength between related components to decrease; as the pressure inside the battery cell continues to increase, it will also cause the connection between the cover plate body and the shell to rupture or even explode. At this time, if the power is not cut off inside the battery cell, the battery cell is prone to explosion, resulting in aggravated thermal runaway.

[0371] In view of this, the embodiment of the present application further provides a battery cell 003, such as Figures 17-24 The battery cell 003 provided in this application has a simple structure. When the internal pressure of the battery cell 003 is too high, the cover 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 understood that under normal operating conditions, as the charge and discharge cycles of cell 003 reverse, gas will be generated within 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, before cell 003 triggers thermal runaway, the temperature inside cell 003 continues to rise, and a large amount of gas will continue to be generated. During this period, the pressure within cell 003 increases. If the internal pressure of cell 003 exceeds the maximum normal operating pressure and is not relieved in a timely manner, cell 003 may explode or experience thermal runaway.

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

[0374] It should be noted that the first cover portion 102 and the second cover portion 105 are integrally formed, and the second cover portion 105 of this embodiment can be welded to the shell 031. The cover body 108 has a disc-shaped structure. In some embodiments, the material of the cover body 108 can be steel, such as SPCC material, stainless steel materials SUS410, SUS306, SUS316, SUS430, SUS444 and the like. When SPCC material is used, nickel can be plated on both sides of the cover body 108, and the thickness of the coating is 0.3μm to 8μm. The coating thickness on both sides of the cover body 108 can be the same or different. In other embodiments, the material of the cover body 108 can be 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 a circular ring, and the second current collector 111a is a round ring. The second current collector 111a is disposed within the ring of the first current collector 110, and the first and second current collectors 110, 111a do not contact each other. It should be noted that the centers of the first and second current collectors 110, 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 the present invention, a recessed portion 109 is provided on the second cover portion 105. This recessed portion 109 strengthens the deformation resistance of the second cover portion 105, thereby ensuring the connection strength between the second cover portion 105 and the housing 031. This effectively solves the problem in the related art that the increased internal pressure of the battery cell 003 pushes against the cover assembly, causing deformation of the cover assembly, reducing the connection strength between the cover assembly and the housing 031, and even causing the connection between the cover assembly and the housing 031 to explode.

[0377] At the same time, an explosion-proof notch 104 is provided on the first cover portion 102. When the air pressure in the battery cell 003 increases, the cover body 108 breaks at the explosion-proof notch 104, and the gas inside the battery cell 003 is discharged to achieve the purpose of pressure relief, thereby avoiding the second cover portion 105 and the shell 031 from exploding, and further effectively avoiding the battery cell 003 from becoming violent or experiencing thermal runaway.

[0378] It should be noted that in the above embodiment, the explosion-proof notch 104 is integrally formed on the first cover portion 102 of the cover body 108. In other embodiments, the battery cell 003 further includes an explosion-proof disc provided separately from the first cover portion 102, and the explosion-proof notch 104 may also be provided on the disc. The specific structure and location of the disc can be referenced to conventional arrangements in the art and will not be further described here. The selection can be made based on actual circumstances or needs.

[0379] In some embodiments, see 1 and Figure 21 The diameter of the circle containing the outer contour of the shell 031 along its axial projection 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 set on the first cover 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 deviate toward the first hole 103. A first insulating member 117a is provided between the cover body 108 and the pole 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. The first insulating member 117a will protect the explosion-proof notch 104, preventing it from breaking. When a' is greater than 0.75, explosion-proof notch 104 deviates toward recess 109, which provides some protection for explosion-proof notch 104. Greater pressure is required to break explosion-proof notch 104, making thermal runaway more likely in battery cell 003. In some embodiments, the diameter of the circle encompassing the centerline of the orthographic projection of explosion-proof notch 104 on a horizontal plane can be 0.4D1, 0.45D1, 0.5D1, 0.55D1, 0.6D1, 0.65D1, 0.7D1, 0.75D1, or other unspecified values.

[0380] In addition, 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 to 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 unspecified 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 unspecified values.

[0381] Please continue reading Figure 17 and Figure 21, the diameter of the circle where the center line of the orthographic projection of the recessed portion 109 on the horizontal plane lies is D2, D2=fD1, where: 0.5≤f≤0.8 is satisfied. It should be noted that when f is less than 0.5, the recessed portion 109 is offset in the direction close to the explosion-proof notch 104, that is, the distance between the recessed portion 109 and the explosion-proof notch 104 is shortened, and the recessed portion 109 will play a certain protective role for the explosion-proof notch 104. When the air pressure in the battery cell 003 is too high, the explosion-proof notch 104 requires a greater force to break, resulting in an increased risk of explosion or thermal runaway of the battery cell 003. When f is greater than 0.8, the recessed portion 109 is offset in the direction away from the explosion-proof notch 104, the longitudinal dimension of the second cover portion 105 increases, the longitudinal dimension of the cover body 108 increases, and the occupied space increases. In some embodiments, the diameter of the circle where the center line of the orthographic projection of the recess 109 on the horizontal plane lies 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 unspecified values.

[0382] For example, when D1 is 24 mm, D2 may be 12 mm, 13.2 mm, 13.92 mm, 14.4 mm, 14.88 mm, 13.92 mm, 14.4 mm, 14.88 mm, 15.6 mm, 16.32 mm, 16.8 mm, 18 mm, 18.48 mm, 19.2 mm, or other unspecified values. When D1 is 40 mm, D2 may be 20 mm, 22 mm, 23.2 mm, 24 mm, 24.8 mm, 26 mm, 27.2 mm, 28 mm, 30 mm, 30.8 mm, 32 mm, or other unspecified 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, see Figure 1 The thickness of the cover body 108 is H, where D2-D3=2c'H, satisfying: c'>3. It should be noted that while the diameters of the circle containing the center line of the orthographic projection of the cover body 108, the recessed portion 109 on the horizontal plane, and the diameter of the circle containing the center line of the orthographic projection of the explosion-proof notch 104 on the horizontal plane meet their respective proportional relationships, they also need to satisfy D2-D3=2c'H. This configuration can rationally arrange the positions of the explosion-proof notch 104 and the recessed portion 109, improving the space utilization of the battery cell 003.

[0384] Exemplarily, the thickness of the cover body 108 is 0.4-1 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 unspecified values.

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

[0386] Among them, see Figure 21 and Figure 23 Recessed portion 109 is electrically connected to second electrode tab 012, allowing cover body 108 to function as one output electrode. Electrode assembly 107 is electrically connected to second electrode piece 152, allowing the electrode assembly to function as the other output electrode, thereby achieving same-side output. Furthermore, recessed portion 109 disperses the pressure applied to cover body 108, improving its ability to resist deformation. When the pressure inside battery cell 003 increases, recessed portion 109 prevents cover body 108 from experiencing increased force, thereby increasing the battery cell's service life.

[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 as a side of the second cover portion 105 protruding away from the accommodating cavity 311.

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

[0389] It should be noted that the connection method between the recessed portion 109 and the second pole tab 012 is not limited, and the connection method between the pole assembly 107 and the second pole piece 302 is not limited. For example, in one embodiment, in order to control the number of components, the recessed portion 109 is directly connected to the second pole tab 012, and the pole assembly 107 is directly connected to the first pole tab 011. In another embodiment, please refer to Figure 1In order to ensure the 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 arranged between the second pole tab 012 and the second cover portion 105, and the first current collector 110 electrically connects the second pole tab 012 and the recessed portion 109; at the same time, the second current collector 111a is arranged between the first pole tab 011 and the pole assembly 107, and the second current collector 111a electrically connects the first pole tab 011 and the pole assembly 107 at the same time.

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

[0391] In one embodiment, see Figure 21 and Figure 22The thickness of the second cover portion 105 in the area without the recess 109 is H, the thickness of the first cover portion 102 in the area without the explosion-proof notch 104 is H6, and the notch depth of the explosion-proof notch 104 is H32, wherein (H6-H32)=pH1, satisfying: 0.14≤p≤0.6. H6-H32 refers to the thickness of the first cover portion 102 at the explosion-proof notch 104. For ease of description, the thickness of the first cover portion 102 at the explosion-proof notch 104 is H60 (i.e., H60=H6-H32), i.e., H60=pH32. It should be noted that when p is less than 0.14, the thickness of the first cover portion 102 at the explosion-proof notch 104 is small, and the structural strength of the first cover portion 102 at the explosion-proof notch 104 is weak. During normal use of the battery cell, the first cover portion 102 at the explosion-proof notch 104 may break, affecting the normal use of the battery cell 003. When p is greater than 0.6, the structural strength of the first cover portion 102 at the explosion-proof notch 104 is weak, causing the welding plate 116 to disconnect from the first current collector 110 first, causing the battery cell 003 to break without being powered off, 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 notch 104 should not be too shallow, otherwise when the internal air pressure of the battery cell 003 increases, the explosion-proof notch 104 will not be able to break, and the welding plate 116 will first be disconnected from the first current collector 110, causing the battery cell to explode or even thermal runaway; the depth of the explosion-proof notch 104 should not be too deep, otherwise the first cover portion 102 may break during normal use.

[0392] In another embodiment, the thickness of the area of ​​the second cover plate portion 105 where the recessed portion 109 is not provided is H, the thickness of the area of ​​the first cover plate portion 102 where the explosion-proof notch 104 is not provided is H6, the notch depth of the explosion-proof notch 104 is H32, (H6-H32)=qH, and the following is satisfied: 0.1≤q≤0.3. Among them, 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 where the explosion-proof notch 104 is provided is the same as the thickness of the area of ​​the second cover plate portion 105 where the recessed portion 109 is not provided, i.e., H6=H. From this, it can be concluded that H60=qH6. Specifically, when q is less than 0.1, the thickness of the first cover portion 102 at the explosion-proof notch 104 is small, and the structural strength of the first cover portion 102 at the explosion-proof notch 104 is weak. During normal use of the battery cell, the first cover portion 102 at the explosion-proof notch 104 will break, affecting the normal use of the battery cell 003. When q is greater than 0.3, the thickness of the first cover portion 102 at the explosion-proof notch 104 is relatively thick. When the air pressure in the battery cell 003 reaches the second air pressure, the first cover portion 102 at the explosion-proof notch 104 cannot break, 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 unspecified values. Specifically, when the value of 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 the battery cell 003 provided by the present invention is first powered off and then depressurized when thermal runaway occurs, thereby improving the safety performance of the battery cell 003. Specifically, the cover body 108 has a normal state. In the normal state, the first cover portion 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. The explosion-proof notch 104 is provided on the first bottom wall 109b. The first groove 108b is provided above the explosion-proof notch 104. When the internal air pressure of the battery cell 003 increases, the air pressure acts on the cover assembly, holding the cover assembly to move away from the winding core 001. Under the action of the first air pressure, the first groove 108b is flattened (that is, the first inner side wall 110b of the first groove 108b is flush with the upper end face of the first cover portion 102). Figure 17 or Figure 18As shown), at this time, the first cover portion 102 has not yet broken, but the pole assembly 107 is separated from the winding core 001, thereby achieving power off.

[0394] In some embodiments, see Figure 21 and Figure 22 The thickness of the area of ​​the first cover portion 102 where the first groove 108b is not provided is H3 (i.e., H3=H6=H), and the 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 unspecified values. Specifically, when H3 is 1 mm, H4 can be 2 mm, 2.1 mm, 2.4 mm, 2.5 mm, 2.8 mm, 3 mm, 3.5 mm, 3.7 mm, 3.8 mm, 4.2 mm, 4.5 mm, 5 mm, or other unspecified values.

[0395] The depth of the first groove 108b is H50, where H50 = m'H3, satisfying the following: 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 in the battery cell 003 reaches the first pressure, the explosion-proof notch 104 may break first, resulting in the battery cell 003 not being able to properly shut off. When m' is greater than 2, the depth of the first groove 108b is too deep. When the air pressure in the battery cell 003 reaches the first pressure, the terminal assembly 107 and the winding core 001 have not yet broken, resulting in the battery cell 003 not being able to shut off, increasing the risk factor. Exemplarily, 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 1 mm, H50 can be 1 mm, 1.1 mm, 1.18 mm, 1.2 mm, 1.22 mm, 1.25 mm, 1.3 mm, 1.44 mm, 1.5 mm, 1.62 mm, 1.72 mm, 1.8 mm, 1.85 mm, 1.9 mm, 1.92 mm, 1.96 mm, 2 mm or other unlisted values.

[0396] In addition, the thickness of the area of ​​the first bottom wall 109b where the explosion-proof notch 104 is not provided is H6, where H6 = n'H3, satisfying the following relationship: 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 relatively small, the structural strength of the first cover portion 102 is relatively 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 relatively thick, and the space occupied by the cover assembly increases. At the same time, since the explosion-proof notch 104 is provided on the first bottom wall 109b, when the thickness of the first bottom wall 109b increases, the force required to break the explosion-proof notch 104 increases, thereby 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 unspecified 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 unspecified values.

[0397] In one embodiment, to facilitate disconnection between the pole assembly 107 and the winding core 001, the first inner sidewall 110b is inclined relative to the first bottom wall 109b, and the 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 will surround the explosion-proof notch 104, providing a certain degree of protection for the explosion-proof notch, preventing the explosion-proof notch 104 from breaking under the second air pressure. At the same time, the winding core 001 and the pole assembly 107 require greater force to disconnect, increasing the risk factor. When α is greater than 135°, the first inner sidewall 110b and the first bottom wall are directly close to a straight line, and the distance between the pole assembly 107 and the winding core 001 increases, resulting in an increase in the overall space occupied by the battery cell 003. In this embodiment, α can be 55°, 60°, 62°, 75°, 78°, 80°, 84°, 90°, 92°, 99°, 032°, 110b°, 115°, 120°, 125°, 130°, 132°, 135° or other unlisted values.

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

[0399] See also Figure 13In this embodiment, the pole assembly 107 serves as one output pole, and the cover body 108 serves as another output pole. The cover body 108 and the pole assembly 107 are located on the same side. To prevent short circuits, the battery cell 003 also includes a second insulating member 113b. The second insulating member 113b is disposed between the pole assembly 107 and the first connecting plate 111b. The second insulating member 113b serves as an isolation member, preventing contact between the pole assembly 107 and the cover body 108, which could cause a short circuit. Furthermore, the first cover 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. The explosion-proof notch 104 is disposed on the second connecting plate 112b, and the second insulating member 113b abuts against the second connecting plate 112b. This configuration allows the second connecting plate 112b to limit and secure the second insulating member 113b, preventing the second insulating member 113b from slipping and causing a short circuit within the battery cell 003. The first hole 103 is disposed on the first connecting plate 111 b.

[0400] In one embodiment, the second insulating member 113b includes a first insulating portion 114b and a second insulating portion 115b. The 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 circumference of the first insulating portion 114b passes through the first hole 103 and connects to the inner circumference of the second insulating portion 115b. This configuration is intended to provide the second insulating member 113b with a certain degree of protection for the first connecting plate 111b. When the pressure inside the battery cell 003 increases, the first connecting plate 111b will not break first, resulting in the breaking position being located 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 closest to the accommodating cavity 311. The second connecting plate 112b is arranged to be sunken toward the accommodating cavity 311 to form a sunken structure, and the outer circumference of the second insulating portion 115b abuts the sunken structure.

[0401] In some embodiments, the explosion-proof notch 104 is arranged around the first hole 103. This arrangement allows the pole assembly 107 and the winding core 001 to be completely disconnected, so that the battery cell 003 is in a power-off state, thereby reducing the probability of thermal runaway.

[0402] In one embodiment, in order to improve the safety performance of the battery cell 003, when the pressure inside the battery cell 003 changes, the battery cell 003 needs to be powered off first and then depressurized. Figure 17 or Figure 18When the pressure within chamber 311 reaches a first pressure, pole assembly 107 is disconnected from winding core 001. At this first pressure, cover plate body 108 does not break, and pole assembly 107 is disconnected from winding core 001 first. At this point, battery cell 003 is de-energized. After power is removed, battery cell 003 ceases operation, and its temperature does not continue to rise. This controls the pressure within battery cell 003 and improves its safety.

[0403] Exemplarily, the first air pressure is P1, 1.2 MPa≤P1≤1.8 MPa. More specifically, P1 is 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 unspecified values.

[0404] It should be noted that there are various ways to disconnect the pole assembly 107 from the winding core 001 , and in actual application, various ways may occur.

[0405] Form 1: Please refer to Figure 17 A second current collector 111a is provided between the pole assembly 107 and the winding 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 pole tab. When the pressure inside the battery cell 003 exceeds 1.2MPa, the gas inside the battery cell 003 pushes the pole assembly 107 to move away from the winding core 001. As the pressure increases, the pole assembly 107 is disconnected from the second current collector 111a, and the power is cut off inside the battery cell 003.

[0406] Form 2: Please refer to Figure 18 A second current collector 111a is provided between the pole assembly 107 and the winding 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 pole tab. When the pressure inside the battery cell 003 exceeds 1.2 MPa, the gas inside the battery cell 003 pushes the pole assembly 107 to move away from the winding core 001. As the pressure increases, the second current collector 111a is disconnected from the second pole tab, and the power is cut off inside the battery cell 003.

[0407] See also Figure 19At the end of thermal runaway in cell 003, the pressure inside cell 003 rises to a certain level, requiring the explosion-proof valve to open and release the burning material inside cell 003 to prevent cell 003 from exploding. In this embodiment, when the pressure inside cell 003 exceeds 1.8 MPa, cover body 108 ruptures at explosion-proof notch 104, allowing the gas inside cell 003 to escape. Specifically, cover body 108 ruptures at explosion-proof notch 104 when the pressure inside accommodating cavity 311 reaches a second pressure, P2, where P2 > 1.8 MPa. More specifically, P2 is 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] See also Figure 25 In one embodiment, the first electrode tab 011, the second electrode tab 012, and the third electrode tab 013 are die-cut electrodes. Die-cut electrodes refer to cutting electrodes of a desired shape from a non-coated area of ​​a current collector using a mold and a cutting tool, such as a laser cutter.

[0409] In this embodiment, by adopting die-cutting the tabs, the tab molding method 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] See also Figure 25 In one embodiment, the die-cutting width of the die-cut tab is W0, which satisfies 2mm≤W0≤6mm.

[0411] Exemplarily, 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 pole piece to the pole piece tip is within 35% of the pole piece length, the die-cutting width W is 2-4 mm. If the distance from the pole piece to the pole piece tip is greater than 35% of the pole piece length, the die-cutting width W is 4-6 mm. Furthermore, the die-cutting width W gradually increases as the distance from the pole piece tip increases. This reduces the obstruction of the tab flattening at the connection between the tab and the coating area, thereby improving the ease of tab flattening and the efficiency of flattening.

[0413] In this embodiment, through the above-mentioned limitation, on the one hand, it is possible to avoid the pole being easily broken due to the die-cutting width being too small, thereby ensuring the reliability of the connection between the pole tab and the coating area; on the other hand, it is possible to avoid the large resistance to flattening the pole tab due to the large die-cutting width.

[0414] See also 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 track and the length direction of the pole piece.

[0416] Exemplarily, 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, through the above definition, the bending of the tabs can be guided when flattening the tabs, so that adjacent tabs are partially stacked, thereby reducing interference between adjacent tabs and improving the stacking flatness of the tabs after flattening.

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

[0419] Illustratively, 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, through the above-mentioned limitation, on the one hand, it is possible to avoid the tab being cut to too small a size, which is not conducive to forming a sufficient welding surface with the collecting plate after the tab is bent; on the other hand, it is possible to avoid the tab being cut to too large a size, which occupies more space inside the battery cell.

[0421] Understandably, thermal management has always been a focus for new energy vehicles. As the energy density and power density of new energy vehicle batteries continue to increase, battery heat generation increases, making heat dissipation systems with fast cooling speeds and high heat transfer coefficients increasingly important. Related technologies use serpentine tubes around the sides of battery cells in battery modules for cooling. However, the axial thermal conductivity of a cell is much greater than its diametrical thermal conductivity, so using serpentine tubes to cool the sides of a cell is inefficient and prone to thermal runaway.

[0422] In view of this, the embodiment of the present application further provides a battery module, please refer to Figures 26 to 33The battery module provided by the embodiment of the present application has high cooling efficiency, high safety, and low probability of thermal runaway; the battery module will be described in detail below with reference to the relevant drawings.

[0423] See also Figure 26 、 Figure 27 and Figure 28 Battery module 060 includes a cooling device 061 and multiple battery cells 003. Cooling device 061 includes a first cooling plate 062. Each battery cell 003 includes a housing 031, a winding core 001, and a third current collector 066. The portion of housing 031 near the third electrode tab 013 is an end plate 067. End plate 067 and the rest of the housing can be integral or separate. The winding core 001 is located within housing 031. Third current collector 066 is located between end plate 067 and the third electrode tab 013 and is electrically connected to the third electrode tab 013. Third current collector 066 includes a heat conducting portion 666, which is connected to the side of end plate 067 facing the winding core 001. The side of end plate 067 facing away from the winding core 001 is connected to the first cooling plate 062.

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

[0425] It is understandable that the axial flow of the winding core 001 along the battery cell 003 will increase the axial heat generation of the battery cell 003, resulting in a high axial heat level in the battery cell 003. Therefore, a first cooling plate 062 is provided at the bottom of the battery cell 003 to cool and exchange heat along the axial direction of the battery cell 003, 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 collecting part 066 is connected to the shell 031, and a first cooling plate 062 is arranged under the multiple battery cells 003. The bottom of the battery cell 003 is cooled by the first cooling plate 062, and the top of the battery cell 003 can dissipate heat by contact with the air, so that the top and bottom of the battery cell 003 can simultaneously transfer heat energy for dissipation, thereby improving the axial heat dissipation capacity of the battery module 060, and further achieving better control of the temperature of the battery module 060, so that the battery module 060 can be suitable for fast charging and discharging occasions such as high-rate discharge.

[0427] For ease of description, the side of the end plate 067 close to the winding core 001 is a top surface 069 , and the side of the end plate 067 away from the winding core 001 is a 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, an insulating layer is provided on a side of the first cooling plate 062 facing the plurality of battery cells, and the insulating layer is capable of conducting heat.

[0429] The heat conducting portion 666 transfers the heat of the third current collecting member 066 to the end plate 067 , and the end plate 067 transfers the heat to the first cooling plate 062 . The first cooling plate 062 takes the heat away, thereby achieving heat dissipation.

[0430] In one embodiment, the heat conducting portion 666 includes two first side surfaces arranged opposite to each other, one of the first side surfaces is arranged toward the end plate 067, the first side surface arranged toward the end plate 067 is a first heat conducting surface 071, the first heat conducting surface 071 is connected to the end plate 067, and the first heat conducting surface 071 is used to transfer heat to the end plate 067. Furthermore, the end plate 067 includes two second side surfaces arranged opposite to each other, one of the second side surfaces is arranged toward the heat conducting portion 666, and the other second side surface is arranged toward the first cooling plate 062, the second side surface facing the first cooling plate 062 is a second heat conducting surface 072, and the second heat conducting surface 072 is connected to the first cooling plate 062. Specifically, the heat generated by the core 001 and the third current collecting member 066 is transferred to the heat conducting portion 666, the heat conducting portion 666 transfers the heat to the end plate 067 through the first heat conducting surface 071, and the end plate 067 transfers the 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 winding 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 electrode current collector and is located at the end of the winding 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 winding 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 winding core 001 near the first cooling plate 062. The arrangement of these four current collectors is not limited, as long as they can facilitate current transfer. 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 electrode tab 013, and the fourth current collector is connected to the fourth electrode tab 014.

[0432] Specifically, see 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, a third current collector 066 and a fourth current collector are provided at the end of the battery cell 003 near the first cooling plate 062. The area of ​​the third current collector 066 should be neither too large nor too small. If the area of ​​the third current collector 066 is too large, the area of ​​the fourth current collector will be too small, reducing the current collecting capacity and making the fourth current collector susceptible to ablation. If the area of ​​the third current collector 066 is too small, the current collecting capacity will also be reduced, and the third current collector 066 will also be susceptible to ablation.

[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 and the end plate 067 are in contact; in another embodiment, the third current collector 066 and the end plate 067 are welded. It should be noted that the thermal conductivity of the battery cell 003 in the axial direction is more than 200 times that in the radial direction. In this embodiment, by connecting the third current collector 066 and the end plate 067, the negative electrode of the battery cell 003 is directly connected to the housing 031. The end plate 067 of the battery cell 003 serves as a heat conducting component. A first cooling plate 062 is provided at the axial end of the plurality of battery cells 003 to achieve axial heat dissipation of the battery cells 003, thereby better controlling the temperature of the battery module 060 and enabling the battery module to perform fast charging or fast discharging operations such as high-rate discharge without thermal runaway.

[0434] In some embodiments, the weld 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 weld area between the third current collector 066 and the end plate 067 is small, and the adhesion between the third current collector 066 and the end plate 067 is not tight enough, resulting in reduced thermal conductivity of the battery cell 003. When S3 / S2 is greater than 0.05, the weld area between the third current collector 066 and the end plate 067 increases, making welding more difficult and easily affecting the second current collector during welding.

[0435] In some embodiments, see Figure 28 and Figure 29The end plate 067 is formed with a second groove 073, opening toward the winding core 001, and the heat conducting portion 666 is disposed within the second groove 073. During actual installation, the heat conducting portion 666 is first snapped into the second groove 073 and then welded to the bottom of the second groove 073. It should be noted that in this embodiment, the second groove 073 serves two purposes: first, it pre-fixes the heat conducting portion 666 to the second groove 073 to facilitate welding; and second, it serves to reduce the thickness of the end plate 067 of the housing 031, allowing heat to be transferred to the first cooling plate 062 as quickly as possible, achieving heat exchange.

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

[0437] It can be understood that the second groove 073 has a second bottom wall 074 and a second inner side wall 075, and the second inner side wall 075 is arranged 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 portion 666 is protruded in the second groove 073 and 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 portion 666 and a second end away from the heat conducting portion 666. In the direction from the first end to the second end, the second inner side wall 075 is inclined toward the direction close to the second bottom wall 074. The purpose of such a setting is to facilitate welding of the heat conducting portion 666 and the second bottom wall 074.

[0438] In some embodiments, the angle between the second inner sidewall 075 and the second bottom wall 074 is γ, where 105° ≤ γ ≤ 135°. When the angle between the second inner sidewall 075 and the end plate 067 is greater than 135°, the second groove 073 is too large, resulting in a reduced overall thickness of the end plate 067 of the housing 031 and insufficient strength of the end plate 067. When the angle between the second inner sidewall 075 and the end plate 067 is less than 0.01°, the inclination angle of the second inner sidewall 075 is insufficient, increasing welding difficulty. Specifically, the angle between the second inner side wall 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 angle between the second inner side wall 075 and the second bottom wall 074 is 120°. In this way, the strength of the housing 031 can be ensured while facilitating welding of the heat conducting portion 666 to the second bottom wall 074.

[0439] In some embodiments, taking the end of the battery cell 003 close to 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 electrode 013. Since the third current collector 066 is connected to the center area of ​​the winding core 001, correspondingly, in order to facilitate the welding of the third current collector 066 and the shell 031, the second groove 073 is correspondingly arranged in the center area of ​​the end plate 067. For details, please refer to Figure 31 and Figure 32 The end plate 067 has a first portion and a second portion surrounding the first portion, with a second groove 073 formed on the first portion. 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 portion 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 shell 031 is reduced, heat cannot be dissipated in time, and the third current collector 066 is easily ablated. When the thickness of the second bottom wall 074 of the second groove 073 is thinner, the end plate 067 of the shell 031 is partially thin, the force is uneven, and the strength is low, which makes it easy to damage, resulting in a shorter service life of the battery module 060.

[0440] In some embodiments, see Figure 32, 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 heat conducting part 666 is W3, wherein 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 collecting part 066 is connected to the shell 031, so the shell 031 serves as the output end of the battery cell 003. Therefore, when the thickness of the heat conducting part 666 is too large, a cold weld phenomenon is likely to occur during the welding process, resulting in leakage, and the resistance of the battery cell 003 increases accordingly, resulting in a large amount of energy loss during current transfer. When the thickness of the heat conducting part 666 is thin, when the temperature of the battery cell is too high, it is easy to burn, causing damage to the battery module 060 and a reduction in service life.

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

[0442] In one embodiment, see Figure 29 and Figure 31 The third current collector 066 further includes a current collector 076 and a connecting portion 077. The current collector 076 is connected to the core 001, and the connecting portion 077 is connected between the current collector 076 and the heat conducting portion 666. The connecting portion 077 is inclined relative to the heat conducting portion 666. In this embodiment, the current collector 076 is connected to the core 001, and the connecting portion 077 is connected between the current collector 076 and the heat conducting portion 666. The core 001 transfers heat to the current collector 076, which in turn transfers heat to the heat conducting portion 666 via the connecting portion 077. The heat conducting portion 666 then transfers the heat to the end plate 067 of the shell 031. The end plate 067 of the shell 031 then transfers the heat to the first cooling plate 062, completing the heat exchange. More specifically, the end of the connecting portion 077 connected to the collecting portion 076 is the third end, and the end of the connecting portion 077 connected to the heat conducting portion 666 is the fourth end. In the direction from the third end to the fourth end, the connecting portion 077 is tilted toward the direction close to the heat conducting portion 666. In this way, the connecting portion 077 can cooperate with the second inner wall 075 of the second groove 073, which is convenient for pre-fixing the third collecting portion 066 in the second groove 073.

[0443] In some embodiments, see Figure 32The angle β between the connecting portion 077 and the heat conducting portion 666 is 105°≤β≤135°. Specifically, the angle between the second inner side wall 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 the same. More specifically, as an optional embodiment, the angle between the second inner wall 075 and the second bottom wall 074 is 120°, and the angle between the connecting portion 077 and the heat conducting portion 666 is 120°. Such a setting can not only ensure the strength of the shell 031, but also the connecting portion 077 and the second inner wall 075 of the second groove 073 can fit more closely, which is beneficial to heat transfer and can facilitate welding of the heat conducting portion 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 flat. The purpose of setting it as a flat surface is to facilitate heat transfer and improve cooling efficiency.

[0445] In some embodiments, see Figure 33 The cooling device 061 further includes a cooling assembly 078, which includes a plurality of second cooling plates 079 extending from the first cooling plate 062 on the side near the battery cells 003. The plurality of second cooling plates 079 are connected to the first cooling plate 062 and are thermally connected to the radial sidewalls of the battery cells. In this embodiment, each second cooling plate 079 includes an opposing water inlet and a water outlet. During cooling, the cooling medium enters the second cooling plate 079 from the water inlet and flows out of the second cooling plate 079 from the water outlet. Furthermore, the cooling assembly 078 further includes a plurality of connectors 120. A connector 120 is provided between each two adjacent second cooling plates 079. One end of the connector 120 is connected to the water inlet of one of the second cooling plates 079, and the other end is connected to the water outlet of another second cooling plate 079. In this configuration, the plurality of second cooling plates 079 are sequentially connected via the plurality of connectors 120.

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

[0447] In addition, in this embodiment, see Figure 33In order to improve the cooling efficiency, the second cooling plate 079 is set 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 the heat dissipation capacity.

[0448] It should be noted that, in this embodiment, the cooling device 061 cools the multiple battery cells 003 in the axial direction through the first cooling plate 062, and cools the battery cells 003 in the radial direction through the multiple second cooling plates 079. The first cooling plate 062 and the second cooling plate 079 cooperate with each other to improve the cooling efficiency. With such an arrangement, the upper end of the battery module 060 (which can come into contact with the air and dissipate heat by itself), the lower end of the battery module 060 (dissipates heat through the first cooling plate 062), and the middle part of the battery module 060 (dissipates heat through the second cooling plate 079), the combination of multiple heat dissipation methods can better control the temperature of the battery module 060 and avoid thermal runaway.

[0449] Among them, 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, and then flows from the cooling component 078 to the third cooling plate 121a, 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 to complete the heat exchange.

[0450] See also Figure 35 , Figure 35 FIG2 is a schematic diagram of the structure of a battery pack 004 provided in an embodiment of the present application. The embodiment of the present application provides a battery pack 004, which includes a battery box 041 and the aforementioned battery cells 003. The battery box 041 has a receiving cavity. Multiple battery cells 003 are disposed in the receiving cavity.

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

[0452] See also Figure 36 , Figure 36 005 is a schematic diagram of the structure of an electric device 005 provided in an embodiment of the present application. The embodiment of the present application provides an electric device 005, which includes the aforementioned battery cell 003 or battery pack 004, and the battery pack 004 or the battery cell 003 supplies power to the electric device.

[0453] It is understood that the electrical equipment 005 includes, but is not limited to, electric toys, electric tools, battery-powered vehicles, cars, ships, spacecraft, and the like. Electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Spacecraft may include airplanes, rockets, space shuttles, and spacecraft. Cars may include gasoline-powered cars, gas-powered cars, and new energy vehicles.

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

[0455] The battery module 060 provided in the embodiment of the present application is described in detail below in combination with specific examples and data. It should be understood that the following examples are only used to explain the embodiments of the present application and are not used to limit the present application.

[0456] It should be noted that the following embodiments are all tested using cell 003 as an example, with the entire battery pack 004 operating and testing performed based on cell 003. The parameters of cell 003 include S1, S2, W1, W2, W3, and S3.

[0457] Test plan: such as Figure 34 As shown, the middle hole 016 in the middle area of ​​the battery cell 003 is used as the temperature test point T, and the temperature there is collected to determine the heat conduction and heat dissipation capabilities of the third current collecting member 066 .

[0458] Test method:

[0459] 1. Use CCCV charging mode to charge the battery pack 004 at a charging current of 0.5C. When the voltage of the battery pack 004 reaches 4.25V, use 4.25V constant voltage charging. When the charging current drops to 0.02C, stop charging the battery pack 004 and 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 battery cell 003 of the battery pack 004 reaches 80°C; then rest at 35°C for 30 minutes until the temperature of the temperature test point of the battery cell 003 reaches 35°C;

[0461] 3. Repeat step 2 until the SOC reaches 10% and detect the highest temperature of the battery pack.

[0462] A basic group 1, a control group 1 and a control group 2 were set up. The parameters of the basic group 1, the control group 1 and the control group 2 were exactly the same. Among them, the control group 1 was not provided with the first cooling plate 062, and the control group 2 was not provided with the second groove 073 on the end plate 067 of the shell 031. The specific test results are shown in Table 5.

[0463] Table 5 Test results of basic 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 / ℃ 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 of Table 5, it can be seen that the battery pack 004 of the basic group 1 is provided with a first cooling plate 062, and the temperature inside the battery pack 004 is lower than that of the control group 1. The end plate 067 of the shell 031 of the battery 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 in the present application has a high cooling efficiency and can be used in fast charging and discharging occasions such as high-rate discharge.

[0466] Taking basic group 1 as the parameter standard, changing S1 and S2, the specific test results are shown in Table 6.

[0467] Table 6 Test results of Examples 1-4 and Comparative Examples 1-2

[0468]

[0469] According to the verification results in Table 6, it can be seen that: the area of ​​the first heat-conducting surface 071 of Example 1 is smaller than the area of ​​the first heat-conducting surface 071 of Example 2, and the temperature of the battery pack 004 of Example 2 is lower than the temperature of the battery pack 004 of Example 1; the welding area of ​​Example 3 is smaller than the welding area of ​​Example 4, and the temperature of the battery pack 004 of Example 4 is lower than the temperature of the battery pack 004 of Example 3; the area of ​​the first heat-conducting surface 071 of Comparative Example 1 is smaller than the areas of the first heat-conducting surface 071 of Examples 1 and 2, and the temperature of the battery pack 004 of Comparative Example 1 is higher than the temperature of the battery pack 004 of Examples 1 and 2; the welding area of ​​Comparative Example 2 is smaller than the areas of the welding surfaces of Examples 3 and 4, and therefore the temperature of the battery pack 004 of Comparative Example 2 is higher than the temperature of the battery pack 004 of Examples 3 and 4.

[0470] Taking basic group 1 as the parameter standard, changing W1, W2 and W3, the specific test results are shown in Table 7.

[0471] Table 7 Test results of Examples 5-8 and Comparative Examples 3-4

[0472]

[0473] The verification results in Table 7 show that: in Comparative Example 3, the ratio of W1 to W2 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 of the battery pack 004 provided in Examples 5 and 6. In Comparative Example 4, the ratio of W3 to W1 is greater than 1.2. The thickness of the heat conducting portion 666 and the second bottom wall 074 of the second groove 073 is relatively thick, resulting in a cold weld during the welding process. Liquid leakage occurs during the actual test, and the battery pack 004 provided in Comparative Example 4 cannot be used normally.

[0474] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A battery cell, characterized in that: include: A housing having a receiving cavity; A winding core is disposed in the accommodating cavity, the winding core comprising a first pole piece, a second pole piece, and a diaphragm disposed between the first pole piece and the second pole piece, wherein the polarity of the first pole piece and the second pole piece are opposite, and along the axial direction of the winding core, the winding core body has a first end and a second end; a first pole lug, disposed at the first end and connected to the first pole piece; a second pole tab, disposed at the first end and connected to the second pole piece; a third electrode tab, disposed at the second end, the third electrode tab being connected to the first electrode piece or the second electrode piece; A first output pole and a second output pole are provided in the housing. The first output pole is electrically connected to the first electrode tab, and the second output pole is electrically connected to the second electrode tab.

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

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

4. The battery cell according to claim 3, characterized in that The inner diameter of the third tab region is C, and the outer diameter of the winding 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 winding core, from the center of the winding core body to the outside, the second end is sequentially provided with the third tab area and the first peripheral hollow tab area.

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 winding core body is A, satisfying the following: 65%A≤D≤80%A.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The third tab is connected to the first pole piece, and a projection plane perpendicular to the axis of the winding core body is used as a projection plane, and the axial direction of the winding core body is used as a projection direction. In the projection plane, the projection of the first tab before bending and the projection of the third tab before bending at least partially overlap; Alternatively, the third pole tab is connected to the second pole piece, with a plane perpendicular to the axis of the winding core body as the projection plane, and the axial direction of the winding core body as the projection direction. In the projection plane, the projection of the second pole tab before bending at least partially overlaps with the projection of the third pole tab before bending.

8. The battery cell according to claim 1, characterized in that The winding core further includes a fourth pole tab, which is arranged at the second end of the winding core body. One of the third pole tab and the fourth pole tab is connected to the first pole piece, and the other is connected to the second pole piece.

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

10. The battery cell according to claim 8, characterized in that: The multiple layers of the third pole tabs are bent and stacked to form a third pole tab area, and the multiple layers of the fourth pole tabs are bent and stacked to form a fourth pole tab area. Along the radial direction of the core body, from the center of the core body to the outside, the second end is sequentially provided with a third central hollow tab area, the fourth pole tab area and the third pole tab area, and the fourth pole tab area and the third pole tab area respectively extend along the circumference of the core body into closed or open rings.

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 winding core body is A, satisfying: 3%A≤J≤22%A.

12. The battery cell according to claim 8, characterized in that The multiple layers of the third pole tabs are bent and stacked to form a third pole tab area, and the multiple layers of the fourth pole tabs are bent and stacked to form a fourth pole tab area. Along the radial direction of the core body, from the center of the core body to the outside, the second end is sequentially provided with the fourth pole tab area, the third pole tab area and the third peripheral hollow tab area. The fourth pole tab area and the third pole tab area respectively extend along the circumference of the core body into closed or open rings.

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 winding core body is A, satisfying: 85%A≤D<100%A.

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

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

16. The battery cell according to claim 15, characterized in that A plane perpendicular to the axis of the winding core body is used as a projection plane, and the axial direction of the winding core body is used as a projection direction. In the projection plane, the projection of the first tab before bending partially overlaps with the projection of the third tab before bending.

17. The battery cell according to any one of claims 8 to 13, characterized in that: The fourth pole tab is connected to the second pole piece.

18. The battery cell according to claim 17, characterized in that: Taking a plane perpendicular to the axis of the winding core body as a projection plane and the axial direction of the winding core body as a projection direction, in the projection plane, the projection of the second tab before bending at least partially overlaps with the projection of the fourth tab before bending.

19. The battery cell according to claim 1, characterized in that: The multiple layers of the first pole ears are bent and stacked to form a first pole ear area, and the multiple layers of the second pole ears are bent and stacked to form a second pole ear area. Along the radial direction of the core body, from the center of the core body to the outside, the first end is sequentially provided with a first pole ear area, a second middle ring hollow ear area and a second pole ear area. The first pole ear area and the second pole ear area extend along the circumference of the core into closed or open rings respectively.

20. The battery cell according to claim 1, characterized in that The multiple layers of the first pole ears are bent and stacked to form a first pole ear area, and the multiple layers of the second pole ears are bent and stacked to form a second pole ear area. Along the radial direction of the core body, from the center of the core body to the outside, the first end is sequentially provided with a second central hollow ear area, the first pole ear area and the second pole ear area.

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 winding core body is A, satisfying: 3%A≤M≤22%A.

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

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

24. The battery cell according to any one of claims 19 to 23, characterized in that: The outer diameter of the winding core body is A, the outer diameter of the first tab area is G, and the following conditions are met: 35%A≤G≤50%A; and / or the inner diameter of the second tab area is F, and the following conditions are met: 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 to 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 tab is a positive electrode tab, and the second electrode tab is a negative electrode tab.

28. The battery cell according to claim 1, characterized in that The first output pole is a pole assembly, and the second output pole is a cover body, wherein the cover body is covered with the housing to close the accommodating cavity; the pole assembly is mounted on the cover body and electrically connected to the first pole lug; The cover body is provided with a recessed portion, and the recessed portion 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 tab, and the thickness of the welding plate is smaller than the thickness of the region 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 collecting member and a second current collecting member. The first current collecting member and the second current collecting member are located at the same end of the winding core. The first current collecting member is welded to the second electrode tab and the welding plate. The second current collecting member is electrically connected to the first electrode tab and the pole assembly.

31. The battery cell according to claim 30, characterized in that The thickness of the welding plate is H1, the thickness of the first current collecting member is H2, H2=bH1, and the relationship 0.5≤b≤1.2 is satisfied.

32. The battery cell according to claim 29, characterized in that The thickness of the welding plate is H1, and the thickness of the region of the cover plate body where the recessed portion 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 bottom plate for defining the bottom of the recess, and the welding plate is arranged on the bottom plate.

34. The battery cell according to claim 33, characterized in that The cover plate body further 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 tab. 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.

35. The battery cell according to claim 34, characterized in that The recessed portion includes a first bent connection portion and a second bent connection portion, wherein the first bent connection portion is connected between the side plate and the bottom plate, and the second bent connection portion is connected between the side plate and an area of ​​the cover plate body where the recessed portion is not provided; The thickness of the area of ​​the cover body where the recessed portion is not provided is H, the curvature radius of the first bending connection portion is R1, and the curvature radius of the second bending connection portion is R2, wherein R1=mH, R2=nH, satisfying: 0.8≤m≤2, 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 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 to 31, characterized in that: The thickness of the area of ​​the cover body where the recessed portion is not provided is H, the width of the recessed portion is L1, and the depth of the recessed portion is L2, wherein L1=dH, L2=eH, and the following conditions are satisfied: 2.5≤d≤5, 1.5≤e≤3.

5.

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

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

8.

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

42. The battery cell according to claim 30 or 31, characterized in that: The device further includes a first insulating member, which is disposed between the first current collecting member and the second current collecting member.

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

44. The battery cell according to claim 43, characterized in that The diameter of the circle where the outer contour of the shell is projected along its axial direction is D1, the diameter of the circle where the center line of the orthographic projection of the explosion-proof notch on the horizontal plane is D3, and the diameter of the circle where the center line of the orthographic projection of the recessed portion on the horizontal plane is D2, wherein D3 = a'D1, D2 = fD1, and the following conditions are satisfied: 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, wherein 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 portion is recessed toward the accommodating cavity.

47. The battery cell according to claim 46, characterized in that The thickness of the area of ​​the second cover plate where the recessed portion is not provided is H, the thickness of the area of ​​the first cover plate where the explosion-proof notch is not provided is H6, the notch depth of the explosion-proof notch is H32, (H6-H32)=qH, satisfying: 0.1≤q≤0.

3.

48. The battery cell according to any one of claims 43 to 47, characterized in that: The cover body has a normal state. In the normal state, the first cover 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. The explosion-proof notch 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 portion where the first groove is not provided is H3, the groove 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 where the explosion-proof notch is not provided is H6, wherein H40=k'H3, H50=m'H3, H6=n'H3, satisfying: 2≤k'≤5, 1≤m'≤2, 0.5≤n'≤1.

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

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

52. The battery cell according to any one of claims 43 to 47, characterized in that: It also includes a second insulating member, the first cover portion includes a first connecting plate and a second connecting plate connected to the outer periphery of the first connecting plate, and the explosion-proof notch is 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; Wherein, the first hole is provided on the first connecting plate.

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

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

55. The battery cell according to any one of claims 43 to 47, characterized in that: When the air pressure in the accommodating cavity is a first air pressure, the pole assembly is disconnected from the winding core; When the air pressure in the accommodating cavity reaches a second air pressure, the cover body ruptures at the explosion-proof notch; The first air pressure is P1, the second air pressure is P2, 1.2 MPa≤P1≤1.8 MPa, and P2>1.8 MPa.

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-cutting 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-cutting height of the die-cut tab is H0, which satisfies: 5mm≤H0≤7.5mm.

60. A battery module, characterized in that: include: A cooling device comprising a first cooling plate; And, the battery cell according to any one of claims 1 to 59, wherein there are a plurality of battery cells, each of the battery cells further comprises a third current collector, and a portion of the shell near the third electrode tab is an end plate; Among them, the third current collecting member is located between the end plate and the third pole lug and is electrically connected to the third pole lug. The third current collecting member includes a heat conducting portion, which is connected to the end plate. The side of the end plate facing away from the winding core is connected to the first cooling plate.

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

1.

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

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

1.

64. The battery module according to claim 60 or 61, characterized in that: The end plate is formed with a second groove opening toward 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 portion 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 side wall is inclined relative to the second bottom wall, and an angle γ is included between the second inner side wall and the second bottom wall, 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; A vertical distance between the second bottom wall and a side surface of the end plate facing away from the winding core is W1, and a thickness of the second portion is W2, wherein W1:W2=(0.3-0.6):

1.

67. The battery module according to claim 64, characterized in that A vertical distance between the second bottom wall of the second groove and a side surface of the end plate facing away from the winding core is W1, and a thickness of the heat conducting portion is W3, wherein W3:W1=(0.2-1.2):

1.

68. The battery module according to claim 60 or 61, characterized in that: Both ends of the winding core are provided with tabs of the same polarity. The battery core further includes a first current collector connected to the tab away from the first cooling plate, and the third current collector is connected to the tab close to the first cooling plate.

69. The battery module according to claim 68, characterized in that The first current collecting member further includes a current collecting portion and a connecting portion, wherein the current collecting portion is connected to the winding core, the connecting portion is connected between the current collecting portion and the heat conducting portion, and the connecting portion is inclined relative to the heat conducting portion.

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

71. The battery module according to claim 60 or 61, characterized in that: The side surface 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 also includes a cooling assembly, which includes a plurality of second cooling plates extending from the first cooling plate close to the battery core. The plurality of second cooling plates are connected to the first cooling plate, and the second cooling plates are thermally connected to the radial side wall of the battery core.

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

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

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