Battery cover plate, battery and preparation method of battery

Abstract

The invention discloses a battery cover plate, a battery and a preparation method of the battery, the battery cover plate comprises a cover plate main body part, an explosion-proof part, a roll core connecting part and a sealing part; an explosion-proof part is arranged at the top of the cover plate main body part in a surrounding manner; a concave roll core connecting part is arranged on the inner side of the explosion-proof part; the roll core connecting part is used for being connected with a negative tab at the bottom of a roll core of the battery; the sealing part is arranged in the center of the top of the roll core connecting part; the outer side edge of the periphery of the cover plate main body part is used for being hermetically connected with a bottom opening of a battery shell of the battery; according to the battery cover plate, the battery and the preparation method of the battery disclosed by the invention, the battery cover plate can be safely and reliably connected with the negative electrode lug of the roll core, the reliability of electric connection of the negative electrode side of the battery is ensured, the production quality of the battery is ensured, the yield of the battery is improved, and the battery cover plate has great practical significance.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cover, a battery, and a method for preparing a battery. Background Art

[0002] Lithium-ion batteries have the advantages of high specific energy, many cycles and long storage time. They are not only widely used in portable electronic devices (such as mobile phones, digital cameras and laptops), but also widely used in large and medium-sized electric equipment such as electric vehicles, electric bicycles and electric tools. Therefore, the performance requirements for lithium-ion batteries are getting higher and higher.

[0003] At present, single cells, especially large cylindrical full-ear lithium-ion batteries (large cylindrical batteries, i.e. large-sized cylindrical batteries, such as 4680, 4695 and other large cylindrical batteries), have a complex structure and are difficult to assemble, especially the electrical connection on the negative electrode side. The current conventional physical connection method on the negative electrode side cannot guarantee the connection reliability on the negative electrode side, and the reliability is insufficient, so the reliability of the electrical connection on the negative electrode side of the battery cannot be guaranteed, and the production quality of the battery cannot be guaranteed, which affects the yield rate of the battery.

[0004] Therefore, there is an urgent need to develop a technology that can solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a battery cover, a battery, and a method for preparing a battery in view of the technical defects in the prior art.

[0006] To this end, the present invention provides a battery cover, which includes: a cover body, an explosion-proof portion, a winding core connecting portion, and a sealing portion;

[0007] The bottom of the main body of the cover plate is surrounded by an explosion-proof portion protruding downward;

[0008] A concave winding core connecting portion is provided on the inner side of the explosion-proof portion;

[0009] A winding core connection portion, used to connect to the negative electrode ear at the bottom of the winding core of the battery;

[0010] A sealing portion is provided at the bottom center of the winding core connection portion;

[0011] The outer edges of the main body of the cover plate are used to be sealed and connected with the bottom opening of the battery shell of the battery;

[0012] A circle of cover plate main body flanges protruding outwards is arranged around the outer edges of the cover plate main body;

[0013] The cover plate body flange is used to be sealed and connected with the bottom opening of the battery housing of the battery;

[0014] A circle of concave cover plate main body sinking platform is arranged around the inner side of the cover plate main body flange;

[0015] The explosion-proof part includes: an explosion-proof boss and an explosion-proof notch;

[0016] An explosion-proof boss is disposed protruding downwardly on the inner side of the bottom of the cover plate main body sinking platform on the cover plate main body;

[0017] The explosion-proof boss is provided with a concave explosion-proof notch.

[0018] In addition, the present invention also provides a battery, comprising the battery cover as described above.

[0019] In addition, the present invention also provides a method for preparing the battery as described above, comprising the following steps:

[0020] Step S1, preparing positive electrode sheets and negative electrode sheets;

[0021] Step S2, winding the positive electrode sheet, the negative electrode sheet and the separator, pre-folding the tabs during the winding process, and then flattening the tabs using a tab flattening device to obtain a cylindrical battery winding core after flattening;

[0022] Step S3, performing a laser penetration welding operation between the busbar and the positive electrode ear at the top of the winding core;

[0023] Step S4, for the winding core that has been welded to the busbar, encapsulating the positive electrode ear of the winding core with rubber;

[0024] Step S5, performing a laser penetration welding operation between the battery cover and the negative electrode ear at the bottom of the winding core;

[0025] Step S6, loading the welded core into the battery housing, and then welding the rivet serving as the positive electrode column to the busbar;

[0026] Step S7, performing a laser sealing welding operation between the battery cover plate and the bottom opening of the battery housing;

[0027] Step S8, injecting electrolyte into the battery shell through the center hole of the battery cover, and then performing battery formation. After the formation is completed, inserting the sealing plug, welding the sealing pin in the center groove of the battery cover, and finally preparing the battery.

[0028] It can be seen from the technical solution provided by the present invention above that, compared with the prior art, the present invention provides a battery cover, a battery, and a method for preparing a battery, which are scientifically designed and can safely and reliably connect the battery cover to the negative electrode ear of the winding core, thereby ensuring the reliability of the electrical connection on the negative electrode side of the battery, which is beneficial to ensuring the production quality of the battery and improving the yield rate of the battery, and has great practical significance.

[0029] The present invention eliminates the traditional negative electrode busbar and designs the physical connection method of the negative electrode side as follows: the battery cover plate and the negative electrode ear of the winding core are laser penetrated and welded, that is, the battery cover plate directly penetrates the negative electrode ear of the winding core for laser welding, which can ensure the reliability of the electrical connection on the negative electrode side of the battery, is beneficial to reduce the battery material cost, and improve the battery assembly efficiency and yield rate.

[0030] By applying the present invention, it is helpful to solve the problems of low welding process capability and insufficient welding reliability in the existing battery negative electrode side connection during assembly, effectively reduce the production cost, ensure battery safety, and help improve the market application prospects of battery manufacturers' products. The battery cover plate structure design and battery assembly solution provided by the present invention are highly reliable and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1a It is a schematic diagram of the three-dimensional structure of a battery cover provided by the present invention when placed upside down in Example 1;

[0032] Figure 1b It is a three-dimensional structural schematic diagram of a first embodiment of a battery cover provided by the present invention when placed horizontally and upright;

[0033] Figure 2a It is a schematic diagram of the three-dimensional structure of a second embodiment of a battery cover provided by the present invention when placed upside down;

[0034] Figure 2b It is a three-dimensional structural schematic diagram of a second embodiment of a battery cover provided by the present invention when placed horizontally and upright;

[0035] Figure 3a It is a schematic diagram of the three-dimensional structure of a battery cover provided by the present invention when placed upside down in Example 3;

[0036] Figure 3b It is a schematic diagram of the three-dimensional structure of a battery cover provided by the present invention when placed horizontally and upright;

[0037] Figure 4 Schematic diagram of the welding trajectory of the battery cover plate of Example 1 provided by the present invention when penetrating the welding core (specifically, the negative electrode ear of the core located below);

[0038] Figure 5 Schematic diagram of the welding trajectory of the battery cover plate of the third embodiment provided by the present invention when penetrating the welding coil core (specifically, the negative electrode ear of the coil core located below);

[0039] Figure 6 A battery provided by the present invention is a side cross-sectional view of the negative electrode after the battery housing, the winding core, the battery cover and other components are welded;

[0040] Figure 7 is a cross-sectional view of a battery provided by the present invention;

[0041] In the figure, 1-battery cover; 11-cover body; 111-cover body flange; 112-cover body sink;

[0042] 12-explosion-proof part; 121-explosion-proof boss; 122-explosion-proof notch;

[0043] 13-winding core connecting portion; 14-sealing portion;

[0044] 141 - center boss of the cover plate; 142 - center slot of the cover plate; 143 - center hole of the cover plate.

[0045] 2-sealing nail; 3-sealing rubber plug; 4-battery housing; 5-winding core;

[0046] 6-busbar; 7-rivet; 8-inner gasket; 9-insulating sealing ring. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0049] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] See also Figure 1a to Figure 1b , Figure 2a to Figure 2b , Figure 3a to Figure 3b , Figures 4 to 7 The present invention provides a battery cover, which is applied to a battery, and includes: a cover body 11, an explosion-proof portion 12, a winding core connecting portion 13, and a sealing portion 14;

[0052] The bottom of the cover body 11 is surrounded by an explosion-proof portion 12 protruding downward;

[0053] The inner side of the explosion-proof part 12 is provided with a concave winding core connecting part 13;

[0054] The winding core connecting portion 13 is used to connect with the negative electrode ear at the bottom of the winding core 5 of the battery;

[0055] A sealing portion 14 is provided at the bottom center of the winding core connecting portion 13;

[0056] The outer edges of the cover body 11 are used to be sealed and connected to the bottom opening of the battery housing 4 of the battery.

[0057] It should be noted that the cover plate main body 11 is used to achieve sealing by laser welding with the bottom opening of the battery housing 4;

[0058] The explosion-proof part 12 is used to discharge explosions and release pressure when the battery experiences thermal runaway;

[0059] The winding core connection portion 13 is used to connect to the negative electrode ear at the bottom of the winding core 5 by laser welding, so as to ensure the electrical connection effect;

[0060] The sealing portion 14 is used for battery liquid injection, formation exhaust and subsequent welding with the sealing pin 2.

[0061] In the present invention, a circle of cover plate main body flanges 111 protruding outwards is arranged around the outer edges of the cover plate main body 11;

[0062] The cover body flange 111 is used to be sealed and connected to the bottom opening of the battery housing 4 of the battery.

[0063] A circle of concave cover plate main body sink 112 is arranged around the inner side of the cover plate main body flange 111;

[0064] In a specific implementation, the flange 111 of the cover body and the bottom opening of the battery housing 4 of the battery are sealed by welding (ie, laser welding).

[0065] It should be noted that the cover plate main body flange 111 is located at the outermost area of ​​the battery cover plate and is used to seal the bottom opening of the battery housing 4 .

[0066] In specific implementation, the battery cover is formed by stamping.

[0067] It should be noted that the battery cover is manufactured by stamping, the base material thickness can be selected from 0.3mm to 0.8mm, and the base material can be selected from SPCC (i.e., generally cold-rolled carbon steel sheets and strips) or stainless steel;

[0068] In specific implementation, the cover body flange 111 is connected and sealed with the battery housing 4 by laser welding. Specifically, a ring spot laser can be selected, the laser welding power is 350w-850w, the welding trajectory is a straight line, and the effective welding penetration is 0.10mm-0.35mm.

[0069] In a specific implementation, the inner side surface of the cover plate body flange 111 (ie, the outer edge side surface of the cover plate body sink 112) is a vertical plane.

[0070] In a specific implementation, the outer side surfaces of the flange 111 of the cover body are flush with the outer side surfaces of the bottom opening of the battery housing 4 .

[0071] It should be noted that in order to improve the reliability of laser welding sealing, the outer edge side of the cover body sink 112 is as straight as possible, and the battery cover 1 is tightly matched with the bottom opening area of ​​the battery shell 4 after installation.

[0072] In specific implementation, an explosion-proof portion 12 is disposed around the inner side of the bottom of the cover body sink 112;

[0073] In the present invention, the explosion-proof portion 12 includes: an explosion-proof boss 121 and an explosion-proof notch 122;

[0074] The explosion-proof boss 121 is disposed on the inner side of the bottom of the cover plate main body sinking platform 112 on the cover plate main body 11 in a downwardly protruding manner;

[0075] The explosion-proof boss 121 is provided with a concave explosion-proof notch 122 (a groove protruding downward);

[0076] In specific implementation, Figure 1a , Figure 1b In the battery cover of the first embodiment shown, the explosion-proof boss 121 is circumferentially arranged on the bottom inner side of the cover body sink 112 on the cover body 11, and is spaced apart from the cover center boss 141 of the sealing portion 14 (through the concave winding core connecting portion 13);

[0077] Furthermore, for Figure 1a , Figure 1b In the battery cover of the first embodiment shown, the sealing portion 14, the winding core connecting portion 13 and the explosion-proof portion 12 are sequentially distributed from the inside to the outside along the radial direction of the cover body 11;

[0078] In specific implementation, Figure 2a , Figure 2b In the battery cover of the second embodiment shown, the explosion-proof boss 121 is circumferentially arranged on the bottom inner side of the cover body sink 112 on the cover body 11, and is connected to the cover center boss 141 of the sealing part 14 through three first connecting bosses 1210;

[0079] The three first connection bosses 1210 are used to separate the upwardly concave winding core connection portion 13 into three independent grooves.

[0080] In specific implementation, Figure 3a , Figure 3b The battery cover of the third embodiment shown, the explosion-proof boss 121, includes a circular boss main body part 1211;

[0081] The boss body part 1211 is circumferentially arranged on the inner side of the bottom of the cover body sinking platform 112 on the cover body part 11;

[0082] The inner side of the boss main body part 1211 is connected to the outer sides of the central boss 141 of the cover plate of the sealing part 14 through three second connecting bosses 1212;

[0083] The three second connection bosses 1212 are used to separate the upwardly concave winding core connection portion 13 into three independent grooves.

[0084] In a specific implementation, the explosion-proof notch 122 is in the shape of an arc.

[0085] In a specific implementation, the material thickness at the explosion-proof notch 122 is less than the material thickness of the cover plate main body 11;

[0086] In specific implementation, the explosion-proof notch 122 is formed by stamping;

[0087] It should be noted that the explosion-proof notch 122 is generally stamped, and the shape of the explosion-proof notch 122 can be round or irregular (such as crescent-shaped, L-shaped or arc-shaped), etc. When the battery has thermal runaway, the explosion-proof notch 122 in the explosion-proof portion 12 of the battery cover opens, quickly releasing the pressure inside the battery, thereby effectively improving the safety of the battery.

[0088] It should be noted that the shape of the explosion-proof notch 122 of the battery cover is preferably a ring shape with a notch (ie, an opening) (ie, not a complete ring shape, but actually an arc shape).

[0089] In a specific implementation, the shape of the winding core connection portion 13 (i.e., the shape of the groove) can be, but is not limited to, a "cross shape" (e.g. Figure 1a , Figure 1b shown), "three-petal type" (e.g. Figure 2a , Figure 2b shown) and “ring” (e.g. Figure 3a , Figure 3b shown) etc.

[0090] In a specific implementation, the winding core connection portion 13 is connected to the negative electrode ear at the bottom of the winding core 5 by laser welding.

[0091] Furthermore, the welding trajectory A of the laser welding is in the shape of a straight line (eg Figure 4 As shown), the shape of the spiral (as Figure 5 as shown) or in the shape of a sine curve.

[0092] It should be noted that the laser welding between the core connection portion 13 and the negative electrode ear at the bottom of the core 5 can be performed by a single-mode continuous laser, the laser welding power is 300w-850w, the welding trajectory can be in the form of a straight line, a spiral line, a sine curve, etc., the effective welding strength is greater than 40N, and the effective penetration depth is greater than 0.10mm;

[0093] In a specific implementation, the winding core connection portion 13 is connected to the negative electrode ear at the bottom of the winding core 5 by laser penetration welding.

[0094] It should be noted that the welding trajectory of the laser penetration welding between the winding core connection portion 13 and the negative electrode ear of the winding core 5 is generally: a radially distributed welding trajectory, or a radially distributed welding trajectory and a circumferentially distributed welding trajectory.

[0095] It should be noted that the size range of the winding core connection portion 13 should be consistent with the existing electrode group weldable area formed by cutting and stacking the electrode lugs, and generally φ15mm-φ40mm can be selected (that is, the size range of the winding core connection portion 13, that is, the distribution range, is the size range area between 15mm and 40mm from the center point of the cover plate center hole 143);

[0096] In the present invention, in a specific implementation, the upper concave depth of the winding core connecting portion 13 is greater than or equal to the upper concave depth of the cover plate main body sinking platform 112 of the cover plate main body 11;

[0097] In the present invention, Figure 1a to Figure 1b , Figure 2a to Figure 2b , Figure 3a to Figure 3b , Figure 6 As shown, a sealing portion 14 is provided at the bottom center of the winding core connecting portion 13;

[0098] The sealing part 14 is used for liquid injection, exhaust and sealing of the battery cell;

[0099] In a specific implementation, the sealing portion 14 includes a central boss 141 of the cover plate distributed around;

[0100] The cover plate center boss 141 is disposed at the bottom of the winding core connecting portion 13 in a downwardly protruding manner;

[0101] A concave cover plate center slot 142 is provided at the bottom center of the cover plate center boss 141;

[0102] A cover plate center hole 143 is vertically penetrated at the center position of the cover plate center slot 142;

[0103] Furthermore, the central groove 142 of the cover plate is welded and sealed to a sealing pin 2 .

[0104] Furthermore, a sealing rubber plug 3 is inserted into the central hole 143 of the cover plate;

[0105] Furthermore, there is an interference fit between the sealing rubber plug 3 and the central hole 143 of the cover plate.

[0106] It should be noted that the central groove 142 of the cover plate is used to accommodate the placement and welding of the sealing pin 2; the central hole 143 of the cover plate is used to inject liquid (inject electrolyte) into the winding core (i.e., the battery cell electrode group) placed inside the battery shell, and to place the sealing plug 3.

[0107] Furthermore, the central slot 142 of the cover plate is connected to the sealing pin 2 by laser welding;

[0108] The welding track of laser welding is in the shape of a straight line or a circle.

[0109] It should be noted that, in specific implementation, for the battery assembled with the battery cover of the present invention, after the injection and exhaust operations are completed, the sealing plug 3 is inserted into the center hole 143 of the cover, and then the center groove 142 of the cover is connected with the sealing pin 2 by laser welding to achieve sealing. Specifically, a single-mode continuous laser can be selected, and the laser welding power is 300w-600w. The welding trajectory of the laser welding can be straight, circular, etc.

[0110] It should be noted that the shape and size of the sealing pin 2 correspond to the shape and size of the central slot 142 of the cover plate into which the central hole 143 of the cover plate has been inserted into the sealing rubber plug 3. The overall cross-sectional shape of the sealing pin 2 is circular.

[0111] Further, the bottom surface of the cover plate center slot 142 is a horizontal plane;

[0112] The angle between the side walls and the top surface of the central slot 142 of the cover plate is greater than or equal to 90°.

[0113] It should be noted that in order to ensure the welding effect of the sealing pin 2, it is generally necessary to perform dry ice cleaning or laser cleaning on the center groove 142 of the cover plate corresponding to the sealing pin 2. To ensure the cleaning effect, the angle between the side and the top surface of the center groove 142 of the cover plate is generally not less than 90 degrees.

[0114] It should be noted that, for the present invention, the battery cover mainly includes a cover body, an explosion-proof part, a core connection part and a sealing part. The cover body is laser welded with the battery shell to seal the bottom opening of the battery shell; an explosion-proof notch is provided in the explosion-proof part, and the material thickness at the notch is less than the thickness of the cover body, which plays a role of explosion-proof pressure relief under extreme circumstances; the core connection part is used to be welded to the negative electrode ear of the core to maintain electrical connection; the sealing part is used to achieve the sealing of the battery after the battery cell is filled with liquid and the formation exhaust operation.

[0115] Based on the battery cover provided by the present invention, see Figure 6 , Figure 7 As shown, the present invention also provides a battery, which includes the battery cover mentioned above.

[0116] In the present invention, in a specific implementation, the battery comprises a hollow, cylindrical battery housing 4;

[0117] A winding core (i.e., a battery cell electrode group) 5 is arranged in the battery housing 4;

[0118] The top of the battery housing 4 is sealed with a positive electrode cover plate (which is a positive electrode column assembly) serving as a positive electrode output terminal;

[0119] The positive electrode ear at the top of the winding core (i.e., the battery cell electrode group) 5 is connected to a busbar 6 (specifically, welded);

[0120] The busbar 6 is connected to the positive electrode cover plate (which is a positive electrode column assembly);

[0121] The bottom of the battery housing 4 is sealed with a battery cover plate 1 as described above, which serves as a negative electrode output terminal;

[0122] The top of the battery cover 1 is connected to the negative electrode ear at the bottom of the winding core (i.e., the battery cell electrode group) 5;

[0123] The edges of the battery cover plate 1 are sealed and connected to the inner side walls around the bottom opening of the battery housing 4 (specifically, they are welded and fixed).

[0124] In specific implementation, the positive electrode ear at the top of the winding core (i.e., the battery cell electrode group) 5 is welded and fixed to the bottom surface of the busbar 6;

[0125] The top surface of the busbar 6 is welded and fixed to the bottom of the positive electrode cover plate.

[0126] In a specific implementation, the negative electrode ear at the bottom of the winding core (i.e., the battery cell electrode group) 5 and the positive electrode ear at the top of the winding core (i.e., the battery cell electrode group) 5 are both full electrode ears.

[0127] In a specific implementation, the battery cover plate 1 and the negative electrode ear at the bottom of the winding core (ie, the battery cell electrode group) 5 are connected by laser welding, and specifically, laser penetration welding can be adopted.

[0128] In specific implementation, the positive electrode cover plate (which is a positive electrode column assembly) includes: a rivet 7 and an insulating sealing ring 9;

[0129] The circumferential outer wall of the rivet 7 is covered with an insulating sealing ring 9;

[0130] An insulating sealing ring 9 is located between the top opening of the battery housing 4 and the rivet 7;

[0131] Furthermore, a circular inner gasket 8 (which is an insulating gasket) is sleeved on the outer side of the lower part of the insulating sealing ring 9;

[0132] Furthermore, the inner gasket 8 is located between the insulating sealing ring 9 and the busbar 6 .

[0133] Further, the rivet 7 is formed by cold heading or machining;

[0134] The insulating sealing ring 8 is integrally injection-molded, and its material can be selected from PPS, PBT, PFA, etc.

[0135] It should be noted that the battery housing 4 and the positive electrode cover are separated and insulated from each other (for example, separated from each other by an insulating sealing ring 8 ).

[0136] It should also be noted that, in the present invention, after the rivet 7 and the battery housing 4 are riveted together, the outer sides of the insulating seal ring 8 abut against the inner wall of the top opening of the battery housing 4 to play an insulating role.

[0137] It should be noted that the rivet 7 is used to be riveted to the center of the top panel of the battery housing 4. The insulating seal ring 8 is fixed by the rivet 7 and the battery housing 4.

[0138] It should be noted that the battery mainly includes components such as a battery cover, a winding core, a busbar and a battery case. The busbar and the positive pole ear of the winding core are welded to maintain electrical connection; the rivet 7 serving as the positive electrode column is welded to the busbar to maintain electrical connection; the battery cover 1 is welded to the negative pole ear of the winding core to maintain electrical connection.

[0139] For the present invention, in order to prepare the above-mentioned battery, the present invention also provides a method for preparing the battery, comprising the following steps:

[0140] Step S1, using laser cutting equipment (existing equipment) to prepare positive and negative electrode sheets with tabs cut;

[0141] It should be noted that the full-pole ear technology is proposed in contrast to the traditional single-pole ear or multi-pole ear. The current full-pole ear technology for lithium-ion batteries mainly includes two types, namely, flattened pole ear forming and cut and stacked pole ear forming. The cut and stacked pole ear forming technology is widely used because of its low self-discharge rate and less metal foreign matter. In order to ensure the flattening effect of the cut pole ear, the pole ears on the edges of the positive and negative electrode sheets need to be cut with laser die-cutting equipment. The pole ears after cutting are cut pole ears.

[0142] It should be noted that the preparation technology of the positive and negative electrode sheets with cut tabs is the existing well-known preparation technology of full-tab batteries, which will not be described in detail here.

[0143] It should be noted that the method for preparing the positive electrode sheet and the negative electrode sheet in step S1 is a conventional method.

[0144] Step S2, winding the positive electrode sheet, the negative electrode sheet and the separator, pre-folding the tabs during the winding process, and then flattening the tabs using a tab flattening device (the tab flattening operation is an existing conventional tab processing operation, and is performed using an existing tab flattening device), and a cylindrical battery winding core is obtained after flattening;

[0145] In step S2, the separator is located between the positive electrode sheet and the negative electrode sheet to separate the two and avoid short circuit.

[0146] Step S3, performing a laser penetration welding operation between the busbar 6 and the positive electrode ear at the top of the winding core 5;

[0147] Step S4, for the winding core 5 that has been welded to the busbar 6, encapsulating the positive electrode ear of the winding core 5 with glue;

[0148] Step S5, performing a laser penetration welding operation between the battery cover plate 1 and the negative electrode ear at the bottom of the winding core 5;

[0149] Step S6, loading the welded winding core 5 into the battery housing 4, and then welding the rivet 7 serving as the positive electrode column to the busbar 6;

[0150] Step S7, performing a laser sealing welding operation between the battery cover plate 1 and the bottom opening of the battery housing 4;

[0151] Step S8, injecting electrolyte into the battery housing 4 through the central hole 143 in the battery cover 1, and then performing the battery formation operation. After the formation is completed, inserting the sealing plug 3, and welding the sealing pin 2 in the central groove 142 of the battery cover 1, finally preparing a battery (specifically a single cylindrical lithium-ion battery).

[0152] Compared with the prior art, the present invention provides a battery cover, a battery, and a method for preparing a battery. The battery cover is scientifically designed and can safely and reliably connect the battery cover to the negative electrode ear of the winding core, thereby ensuring the reliability of the electrical connection on the negative electrode side of the battery, which is beneficial to ensuring the production quality of the battery and improving the yield rate of the battery, and has great practical significance.

[0153] The present invention eliminates the traditional negative electrode busbar and designs the physical connection method of the negative electrode side as follows: the battery cover plate and the negative electrode ear of the winding core are laser penetrated and welded, that is, the battery cover plate directly penetrates the negative electrode ear of the winding core for laser welding, which can ensure the reliability of the electrical connection on the negative electrode side of the battery, is beneficial to reduce the battery material cost, and improve the battery assembly efficiency and yield rate.

[0154] By applying the present invention, it is helpful to solve the problems of low welding process capability and insufficient welding reliability in the existing battery negative electrode side connection during assembly, effectively reduce the production cost, ensure battery safety, and help improve the market application prospects of battery manufacturers' products. The battery cover plate structure design and battery assembly solution provided by the present invention are highly reliable and easy to industrialize.

[0155] By applying the present invention, due to the special design of the structure of the battery cover, the traditional negative busbar of the single battery is eliminated, the assembly process of the single cylindrical battery is reduced, and cost reduction and efficiency improvement are achieved.

[0156] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A battery cover, It is characterized in that include: A cover plate main body (11), an explosion-proof portion (12), a winding core connection portion (13), and a sealing portion (14); The bottom of the cover plate main body (11) is surrounded by an explosion-proof portion (12) protruding downward; A concave winding core connecting portion (13) is provided on the inner side of the explosion-proof portion (12); A winding core connecting portion (13), used for connecting to the negative electrode ear at the bottom of the winding core (5) of the battery; A sealing portion (14) is provided at the bottom center of the winding core connecting portion (13); The outer edges of the cover plate main body (11) are used to be sealed and connected to the bottom opening of the battery housing (4) of the battery; A circle of cover plate main body flanges (111) protruding outwards are arranged around the outer edges of the cover plate main body (11); The cover plate body flange (111) is used for sealingly connecting with the bottom opening of the battery housing (4) of the battery; A circle of concave cover plate main body sinking platform (112) is arranged around the inner side of the cover plate main body flange (111); The explosion-proof part (12) comprises an explosion-proof boss (121) and an explosion-proof notch (122); An explosion-proof boss (121) is disposed protruding downward on the inner side of the bottom of the cover plate main body sink (112) on the cover plate main body (11); A concave explosion-proof notch (122) is provided on the explosion-proof boss (121).

2. The battery cover as claimed in claim 1, It is characterized in that The cover plate body flange (111) and the bottom opening of the battery housing (4) of the battery are sealed and connected by laser welding; and / or, The winding core connection portion (13) is connected to the negative electrode ear at the bottom of the winding core (5) by laser welding; and / or, An explosion-proof portion (12) is disposed around the inner side of the bottom of the cover plate main body sinking platform (112); and / or, The inner side surface of the flange (111) of the cover plate body is a vertical plane; and / or, The outer side surfaces of the flange (111) of the cover body are flush with the outer side surfaces of the bottom opening of the battery housing (4); and / or, The concave depth of the winding core connection portion (13) is greater than or equal to the concave depth of the cover plate main body sinking platform (112) of the cover plate main body portion (11); and / or, The material thickness at the explosion-proof notch (122) is smaller than the material thickness of the cover plate main body (11); and / or, The explosion-proof notch (122) is in the shape of a circular ring with an opening.

3. The battery cover as claimed in claim 1, It is characterized in that The explosion-proof boss (121) is circumferentially arranged on the inner side of the bottom of the cover plate main body sink (112) on the cover plate main body (11), and is spaced apart from the cover plate central boss (141) of the sealing part (14); The sealing portion (14), the winding core connection portion (13) and the explosion-proof portion (12) are sequentially distributed from the inside to the outside along the radial direction of the cover plate main body (11).

4. The battery cover as claimed in claim 1, It is characterized in that The explosion-proof boss (121) is circumferentially arranged on the inner bottom side of the cover plate main body sink (112) on the cover plate main body (11), and is connected to the cover plate central boss (141) of the sealing part (14) and the cover plate central boss (141) of the sealing part (14) through three first connecting bosses (1210); The three first connection bosses (1210) are used to separate the upwardly concave winding core connection portion (13) into three independent grooves.

5. The battery cover as claimed in claim 1, It is characterized in that The explosion-proof boss (121) comprises a circular boss main body part (1211); The boss body part (1211) is disposed circumferentially on the inner side of the bottom of the cover plate body sink (112) on the cover plate body part (11); The inner side of the boss main body part (1211) is connected to the outer sides of the central boss (141) of the cover plate of the sealing part (14) through three second connecting bosses (1212); The three second connection bosses (1212) are used to separate the upwardly concave winding core connection portion (13) into three independent grooves.

6. The battery cover as claimed in claim 1, It is characterized in that The sealing portion (14) includes a central boss (141) of the cover plate distributed around the central boss; The cover plate central boss (141) is arranged at the bottom of the winding core connecting portion (13) in a downwardly protruding manner; A concave cover plate center slot (142) is provided at the bottom center of the cover plate center boss (141); A cover plate center hole (143) is vertically penetrated at the center position of the cover plate center slot (142); The central groove (142) of the cover plate is welded and sealed to a sealing pin (2); A sealing rubber plug (3) is inserted into the central hole (143) of the cover plate.

7. The battery cover as claimed in claim 6, It is characterized in that The sealing rubber plug (3) and the central hole (143) of the cover plate are in interference fit; and / or, The bottom surface of the central slot (142) of the cover plate is a horizontal surface; The included angle between the surrounding side walls and the top surface of the central slot (142) of the cover plate is greater than or equal to 90°.

8. A battery, It is characterized in that Comprising the battery cover according to any one of claims 1 to 7.

9. The battery according to claim 8, It is characterized in that The battery comprises a hollow, cylindrical battery housing (4); A winding core (5) is arranged inside the battery housing (4); A positive electrode cover plate serving as a positive electrode output terminal is sealed and arranged on the top of the battery housing (4); The positive electrode ear at the top of the winding core (5) is connected to a busbar (6); A busbar (6) connected to the positive electrode cover plate; The bottom of the battery housing (4) is sealed with a battery cover as described in any one of claims 1 to 7 as a negative electrode output terminal; The top of the battery cover (1) is connected to the negative electrode ear at the bottom of the winding core (5); The edges of the battery cover plate (1) are sealed and connected to the inner side walls around the bottom opening of the battery housing (4); The positive electrode cover comprises: a rivet (7) and an insulating sealing ring (9); The circumferential outer wall of the rivet (7) is covered with an insulating sealing ring (9); An insulating sealing ring (9) is located between the top opening of the battery housing (4) and the rivet (7); The lower outer side of the insulating sealing ring (9) is sleeved with a circular inner gasket (8).

10. A method for preparing a battery as claimed in claim 8 or 9, It is characterized in that The following steps are involved: Step S1, preparing positive electrode sheets and negative electrode sheets; Step S2, winding the positive electrode sheet, the negative electrode sheet and the separator, pre-folding the tabs during the winding process, and then flattening the tabs using a tab flattening device to obtain a cylindrical battery winding core after flattening; Step S3, performing a laser penetration welding operation between the busbar (6) and the positive electrode ear at the top of the winding core (5); Step S4, for the winding core (5) after welding with the busbar (6), the positive electrode ear of the winding core (5) is coated with rubber; Step S5, performing a laser penetration welding operation between the battery cover plate (1) and the negative electrode ear at the bottom of the winding core (5); Step S6, loading the welded winding core (5) into the battery housing (4), and then welding the rivet (7) serving as the positive electrode column to the busbar (6); Step S7, performing a laser sealing welding operation between the battery cover plate (1) and the bottom opening of the battery housing (4); Step S8, injecting electrolyte into the battery housing (4) through the central hole (143) in the battery cover (1), and then performing a battery formation operation. After the formation is completed, inserting the sealing rubber plug (3), and welding the sealing pin (2) in the central groove (142) of the battery cover (1), finally preparing a battery.

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