CN114914515A

CN114914515A - Lithium battery and preparation method thereof

Info

Publication number: CN114914515A
Application number: CN202210364737.6A
Authority: CN
Inventors: 王义源; 田秀君; 董丽; 薄晋科; 曹仕良; 孙喜龙
Original assignee: Dalian CBAK Power Battery Co Ltd
Current assignee: Dalian CBAK Power Battery Co Ltd
Priority date: 2022-04-07
Filing date: 2022-04-07
Publication date: 2022-08-16

Abstract

The invention provides a lithium battery and a preparation method thereof, wherein the lithium battery comprises the following components: the shell is provided with an accommodating cavity, the winding core is arranged in the accommodating cavity, the anode of the winding core is positioned at the opening, the anode current collecting disc comprises a first disc body and a first bulge, the first disc body is connected with the anode of the winding core, the first bulge axially extends along the first disc body, the insulating ring is sleeved on the first disc body, the cover body component comprises a rivet, a cover plate, an insulating component and a sealing nail, the rivet is provided with a first through hole, the first bulge is attached to the inner wall surface of the first through hole, the cover plate is connected with the insulating ring and the rivet through the insulating component, the sealing nail is arranged in the first through hole, the positive electrode of the winding core is directly welded with the positive current collecting disc, the positive current collecting disc is directly welded with the rivet and the sealing nail through the first bulge, the structure has the advantages of simpler preparation process, strong overcurrent capacity and small internal resistance of the battery, and can meet the requirement of high-rate quick charge and discharge performance of the lithium battery.

Description

Lithium battery and preparation method thereof

Technical Field

The invention relates to the technical field of batteries, in particular to a lithium battery and a preparation method thereof.

Background

At present, the structure of a lithium battery mainly comprises a single-pole lug structure, a multi-pole lug structure and a full-pole lug structure, wherein the single-pole lug structure and the multi-pole lug structure mainly weld pole lugs from the edges or the middle of a positive pole piece and a negative pole piece and are welded with a shell and a cap through the pole lugs.

The full-tab structure is characterized in that when the positive and negative current collectors are coated, a piece of empty foil area is reserved at the edge of the full-tab structure, after the full-tab structure is wound, the empty foil area is rubbed and leveled, the current collecting disc is welded at the rubbing and leveling position, and the full-tab structure is welded with the shell and the cover cap through the current collecting disc. Therefore, compared with a single-pole lug and a multi-pole lug structure, the existing full-pole lug structure has more excellent multiplying power charge-discharge performance.

However, the existing lithium battery with a full-tab structure still has the following defects: the positive and negative electrodes of the structure are arranged on the opposite sides of the lithium battery, and the structure of the battery module is complex; and the battery can not meet the performance requirements of high-rate quick charge and quick discharge due to the size of the connecting sheet on the positive current collecting disc and the size of resistance welding of the negative current collecting disc.

Disclosure of Invention

The invention provides a lithium battery and a preparation method thereof, which are used for solving the problem that the lithium battery in the prior art cannot meet the requirement of high-rate quick-charging and quick-discharging performance.

In a first aspect, the present invention provides a lithium battery comprising: the device comprises a shell, a winding core, a positive current collecting disc, an insulating ring and a cover body assembly;

the shell is provided with an accommodating cavity, the accommodating cavity is provided with an opening, the winding core is arranged in the accommodating cavity, and the anode of the winding core is positioned at the opening;

the positive collector plate comprises a first plate body and a first bulge, the first plate body is connected with the positive electrode of the winding core, and the first bulge axially extends along the first plate body; the insulating ring is sleeved on the first tray body;

the cover body assembly comprises a rivet, a cover plate, an insulation assembly and a sealing nail, the rivet is provided with a first through hole, and the first bulge is attached to the inner wall surface of the first through hole; the cover plate covers the opening, and the cover plate is connected with the rivet through the insulating assembly; the sealing nail is embedded in the first through hole and attached to the first protrusion.

According to the lithium battery provided by the invention, the sealing nail is provided with a first chamfer at the intersection of the sealing nail, the first bulge and the rivet, and/or the rivet is provided with a second chamfer at the intersection of the sealing nail, the first bulge and the rivet.

According to the lithium battery provided by the invention, the positive electrode current collecting disc further comprises a first groove, the first groove is formed by extruding and sinking from the end face of the first disc body to the positive electrode of the winding core, and the positive electrode current collecting disc is connected with the positive electrode of the winding core through the first groove in a welding mode.

According to the lithium battery provided by the invention, under the condition that the first grooves are multiple, the multiple first grooves are sequentially arranged along the circumferential direction of the first tray body.

According to the lithium battery provided by the invention, the positive electrode current collecting plate further comprises a second through hole, and the second through hole is formed between every two adjacent first grooves.

According to the lithium battery provided by the invention, the insulation assembly comprises a first insulation piece and a second insulation piece, the first insulation piece is clamped between the cover plate and the insulation ring, and the second insulation piece is clamped between the rivet and the cover plate.

According to the lithium battery provided by the invention, the lithium battery further comprises a negative current collecting disc, the negative current collecting disc comprises a second disc body and a second groove, the second groove is formed by extruding and sinking from the end face of the second disc body to the negative electrode of the winding core, and the negative current collecting disc is connected with the negative electrode of the winding core through the second groove.

According to the lithium battery provided by the invention, the shell is provided with a first end and a second end which are opposite, the first end of the shell is connected to the second tray body, and the second end of the shell is connected to the cover plate.

In a second aspect, the present invention also provides a method for preparing a lithium battery as described in any of the above, including:

laser welding the positive electrode of the winding core and the positive electrode current collecting disc;

laser welding the negative electrode of the winding core and the negative electrode current collecting disc;

assembling an insulating ring and the positive current collecting disc;

putting the winding core into a shell, and performing a rolling groove process;

assembling a cover assembly to the positive side of the winding core;

laser welding the contact part of the top of the shell and the cover body assembly;

and performing laser welding on the contact position of the bottom surface of the shell and the anode current collecting disc.

According to the preparation method of the lithium battery provided by the invention, the assembling of the cover body assembly to the positive electrode side of the winding core specifically comprises the following steps:

assembling a cover plate on the positive side of the winding core;

and assembling a rivet and the first bulge of the positive current collecting plate so that the first bulge penetrates through the first through hole of the rivet and is in contact with the inner wall surface of the first through hole.

The lithium battery and the preparation method thereof provided by the invention are characterized in that a first bulge is arranged on a positive current collecting disc in the lithium battery, the positive current collecting disc is in contact with a sealing nail and a rivet through the first bulge, so that the conduction of the positive current is realized, in addition, the rivet and the sealing nail are respectively attached to the two sides of the first bulge, the contact area of the positive current collecting disc with the rivet and the sealing nail is increased, and the overcurrent capacity is enhanced.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

Fig. 1 is an exploded structural view of a lithium battery provided in an embodiment of the present invention;

fig. 2 is a schematic front view of a lithium battery provided in an embodiment of the present invention;

FIG. 3 is a schematic sectional view A-A of FIG. 2;

FIG. 4 is an enlarged partial schematic view of FIG. 3 at A;

FIG. 5 is a schematic view of a portion of the enlarged structure at B in FIG. 3;

FIG. 6 is an enlarged partial schematic view of FIG. 3 at C;

FIG. 7 is a schematic structural diagram of a seal nail provided in accordance with an embodiment of the present invention;

FIG. 8 is a schematic structural view of a rivet provided in accordance with an embodiment of the present invention;

fig. 9 is a schematic top view of a positive current collecting plate according to an embodiment of the present invention;

FIG. 10 is a schematic sectional view A-A of FIG. 9;

fig. 11 is a schematic top view of an anode current collecting plate according to an embodiment of the present invention;

FIG. 12 is a schematic sectional view A-A of FIG. 11;

reference numerals:

1: a housing; 2: a winding core; 3: a positive current collector; 31: a first tray body; 32: a first protrusion; 33: a first groove; 34: a second through hole; 4: a cover assembly; 41: riveting; 411: a first through hole; 412: a second corner cut; 42: a cover plate; 43: an insulating assembly; 431: a first insulating member; 432: a second insulating member; 44: sealing the nail; 441: a first corner cut; 5: a negative current collecting plate; 51: a second tray body; 52: a second groove; 6: an insulating ring.

Detailed Description

In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "provided with", "connected" and the like are to be construed broadly, such as "connected", may be a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through the communication between two elements. The specific meaning of the above terms in the present invention can be understood as appropriate by those of ordinary skill in the art.

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The lithium battery and the method for manufacturing the same according to the present invention will be described with reference to fig. 1 to 12.

In a first aspect, a lithium battery provided in an embodiment of the present invention includes: the device comprises a shell 1, a winding core 2, a positive current collecting disc 3, an insulating ring 6 and a cover body assembly 4.

The casing 1 is equipped with and holds the chamber, holds the chamber and has uncovered, rolls up core 2 and locates and hold the intracavity, and the positive pole that rolls up core 2 is located uncovered department.

The positive collector plate 3 comprises a first plate body 31 and a first bulge 32, the first plate body 31 is connected with the positive electrode of the winding core 2, the first bulge 32 extends along the axial direction of the first plate body 31, and the insulating ring 6 is sleeved on the first plate body 31. The cover assembly 4 includes a rivet 41, a cover plate 42, an insulating assembly 43 and a sealing nail 44, the rivet 41 has a first through hole 411, and the first protrusion 32 is attached to an inner wall surface of the first through hole 411.

The cover plate 42 covers the opening, and the cover plate 42 is connected with the rivet 41 through the insulating assembly 43.

The sealing nail 44 is embedded in the first through hole 411 and attached to the first protrusion 32.

Specifically, as shown in fig. 1, the lithium battery is assembled by a case 1, a winding core 2, a positive electrode current collecting plate 3, an insulating ring 6, and a cover assembly 4. However, the material of the case 1 is other metal material such as nickel-plated carbon steel or stainless steel, and as shown in fig. 2, the case 1 in this embodiment is cylindrical, but the shape of the case 1 is not limited to this, and may be rectangular parallelepiped, cube, or other shape, and may be provided according to the shape of the winding core 2.

Roll up core 2 and form by positive plate, negative pole piece and diaphragm coiling for positive plate, diaphragm parcel negative pole piece of negative pole piece parcel form the anodal and the negative pole of rolling up core 2, when rolling up core 2 and placing in holding of casing 1 the chamber, roll up the anodal uncovered department that is located casing 1 of core 2, roll up the negative pole of core 2 and be located casing 1's bottom.

The positive current collecting disc 3 has two end faces, the back face of the positive current collecting disc 3 is in contact with the positive exposed foil of the winding core 2, the front face of the positive current collecting disc is provided with a first bulge 32, as shown in fig. 10, the first bulge 32 extends along the axial direction of the positive current collecting disc 3, the first bulge 32 has the function of directly conducting positive current to the rivet 41 and the seal nail 44, a connecting sheet structure in the prior art is eliminated, the internal resistance of the battery is reduced, and the overcurrent strength is increased.

In order to maximize the contact area between the rivet 41 and the first protrusion 32, the larger the contact area, the stronger the current passing capability, and the size of the first through hole 411 in the middle of the rivet 41 is matched with the size of the first protrusion 32, so that the fit between the two is suitable.

In view of simplifying the structure of the lithium battery module, the positive electrode and the negative electrode of the lithium battery can be arranged on the same side, that is, the negative electrode of the winding core 2 positioned at the bottom of the shell 1 is connected with the cover plate 42 through the shell 1, so that the cover plate 42 serves as the negative electrode end.

In order to prevent the positive electrode terminal composed of the positive current collecting plate 3, the rivet 41 and the seal nail 44 from communicating with the negative electrode terminal, as shown in fig. 3, an insulating member 43 may be provided around the cap plate 42, and the cap plate 42 may be insulated from the rivet 41 by the insulating member 43. Meanwhile, as shown in fig. 1, a circle of insulating ring 6 is arranged on the outer edge of the first disc body 31 of the positive current collecting disc 3, and the positive current collecting disc 3, the positive electrode of the winding core and the shell 2 are insulated through the insulating ring 6.

The material of the positive current collecting plate 3, the rivet 41 and the sealing nail 44 are all metal materials, which may be the same or different, preferably the same material, and may be aluminum alloy or other metals, the material of the insulating assembly 43 is polypropylene, polyimide or other plastic products, and the material of the casing 1 and the cover plate 42 is nickel-plated carbon steel or other metal materials such as stainless steel.

In the present embodiment, the specific composition of the winding core 2 is as follows:

the positive plate is composed of a positive active substance, a conductive agent and a binder, wherein the active substance is one or more of lithium iron phosphate, lithium manganate, lithium nickel cobalt manganese oxide and lithium cobaltate, and in the embodiment, the binder is polyvinylidene fluoride, styrene butadiene rubber latex and polynitrile series adhesive.

The negative plate is composed of a negative active material, a conductive agent and a binder. The negative active substance is one or more of artificial graphite, natural graphite, mesocarbon microbeads, silica, silicon carbide or lithium titanate, and the binder is one or more of carboxymethyl cellulose, styrene-butadiene rubber latex, polyvinylidene fluoride and polynaphthalene series binders.

The diaphragm is a polypropylene single-layer film, a polyethylene single-layer film, or a polypropylene-polyethylene-polypropylene three-layer composite microporous diaphragm, or a composite diaphragm composed of the diaphragm and ceramics, or a ceramic gluing diaphragm composed of the diaphragm, ceramics and PVDF.

In the lithium battery provided by the embodiment of the invention, the first bulge 32 is arranged on the positive current collecting disc 3, the positive current collecting disc 3 is in contact with the sealing nail 44 and the rivet 41 through the first bulge 32, so that the conduction of the positive current is realized, in addition, the rivet 41 and the sealing nail 44 are respectively attached to the two sides of the first bulge 32, the contact area between the positive current collecting disc 3 and the rivet 41 as well as the contact area between the rivet 41 as well as the sealing nail 44 are increased, and the overcurrent capacity is enhanced.

In an alternative embodiment, the seal pin 44 has a first chamfer 441 at the intersection of the seal pin 44, the first protrusion 32 and the rivet 41, and/or the rivet 41 has a second chamfer 412 at the intersection of the seal pin 44, the first protrusion 32 and the rivet 41.

Specifically, in order to achieve current conduction among the seal nail 44, the first protrusion 32 and the rivet 41 and ensure the sealing performance of the device, as shown in fig. 7, a first chamfer 441 may be provided on the outer circumference of the seal nail 44, i.e., a fillet weld is formed, and laser welding is performed on the fillet weld to weld the three together; as shown in fig. 8, a second chamfer 412 may be provided at the inner ring of the rivet 41, and similarly, a fillet weld may be formed, and laser welding may be performed at the weld to weld the three together.

In the two arrangement modes, welding connection can be achieved through any one of the two arrangement modes, of course, a first chamfer 441 can be arranged on the outer circumference of the sealing nail 44, a second chamfer 412 is correspondingly arranged on the inner circumference of the rivet 41, and the first chamfer 441 and the second chamfer 412 are oppositely arranged to form a V-shaped groove for V-shaped welding. Three welding connection modes can all fall into the protection scope of the embodiment of the invention.

The size of the first chamfer 441 may be the same as or different from that of the second chamfer 412, and the specific size is not limited, and laser welding may be implemented.

In an alternative embodiment, the positive current collecting disk 3 further includes a first groove 33, the first groove 33 is formed by pressing and recessing from the end surface of the first disk body 31 toward the positive electrode of the winding core 2, and the positive current collecting disk 3 is welded and connected with the positive electrode of the winding core 2 through the first groove 33.

Specifically, the positive current collecting disc 3 has two end surfaces, wherein the end surface opposite to the first protrusion 32 is a back surface, and the back surface needs to be in contact with the positive exposed foil of the winding core 2, and in view of facilitating pressing of the positive current collecting disc 3 into the positive exposed foil, as shown in fig. 9, a first groove 33 may be formed by pressing the positive current collecting disc 3 towards the back surface, the first groove 33 is pressed into the positive exposed foil, and laser welding is performed on the positive exposed foil at the first groove 33, so as to ensure the firmness of connection, thereby ensuring conduction of current.

In an alternative embodiment, in the case where the first groove 33 is plural, the plural first grooves 33 are arranged in order in the circumferential direction of the first disc body 31.

Specifically, in order to further improve the current collecting effect of the positive current, a plurality of first grooves 33 may be provided on the disc body of the positive current collecting disc 3, as shown in fig. 9, 4 first grooves 33 are provided, and in order to ensure the uniformity of the current, 4 first grooves 33 are provided around the first protrusion 32. Of course, other numbers of first grooves 33 are also possible, and this is merely an example.

The shape and the size of the first groove 33 are set according to actual conditions, and the shape and the size are not specifically limited, so that the positive exposed foil can be conveniently pressed on the basis of ensuring the diversion.

In an alternative embodiment, the positive collector disc 3 further comprises second through-holes 34, the second through-holes 34 being provided between two adjacent first recesses 33.

Specifically, as shown in fig. 9, a second through hole 34 is provided between every two adjacent first grooves 33, and in the embodiment of the present invention, the second through hole 34 is a weep hole, and functions to facilitate the electrolyte to flow out of the weep hole.

The second through holes 34 may be as shown in fig. 9, each group of weep holes includes three small through holes, the three small through holes are radially arranged along the first disc body 31, and the inner diameters of the three small through holes increase in sequence from inside to outside, and the weep holes may be further configured as a long strip-shaped through hole, which may be regular in size or irregular in size, so that the number and size of the second through holes 34 are not specifically limited, and the electrolyte can flow out from these positions.

In an alternative embodiment, the insulating assembly 43 comprises a first insulating member 431 and a second insulating member 432, the first insulating member 431 is sandwiched between the cover plate 42 and the insulating ring 6, and the second insulating member 432 is sandwiched between the rivet 41 and the cover plate 42.

Specifically, in order to isolate the cover plate 42 from the rivet 41, as shown in fig. 3, an insulating assembly 43 is disposed on an inner circumference of the cover plate 42, and the insulating assembly 43 includes a first insulating member 431 and a second insulating member 432, as shown in fig. 5, the first insulating member 431 is disposed between the cover plate 42 and the insulating ring 6, and further isolates the positive current collecting plate 3 from the cover plate 42, and the structure may be a gasket structure; as shown in fig. 4, the second insulating member 432 is disposed between the rivet 41 and the cover plate 42 to insulate the rivet 41 from the cover plate 42, and the structure of the second insulating member 432 may be a regular shape, for example, an L shape as shown in fig. 4, or an irregular shape, and the specific shape is not limited, and the insulating effect may be achieved.

In an alternative embodiment, the lithium battery further includes an anode current collecting tray 5, the anode current collecting tray 5 includes a second tray body 51 and a second groove 52, the second groove 52 is formed by pressing and recessing from an end surface of the second tray body 51 toward the anode of the winding core 2, and the anode current collecting tray 5 is connected to the anode of the winding core 2 through the second groove 52.

Specifically, as shown in fig. 6, an anode current collecting plate 5 is further disposed between the anode of the lithium battery and the bottom of the case 1, as shown in fig. 10, the anode current collecting plate 5 has two end faces, the upper end face of which needs to contact with the anode exposed foil of the winding core 2, and in view of facilitating the pressing of the anode current collecting plate 5 into the anode exposed foil, as shown in fig. 11, a second groove 52 may be formed by pressing the anode current collecting plate 5 toward the anode of the winding core 2, the second groove 52 is pressed into the anode exposed foil, and the second groove 52 is laser-welded with the anode exposed foil, so as to ensure the connection firmness, thereby ensuring the conduction of the current.

As shown in fig. 12, the lower end surface of the anode current collecting plate 5 contacts the case 1, and in order to facilitate welding of the two, a downward protrusion may be disposed at a central position of the second plate body 51 to contact the anode current collecting plate 5 with the case 1, and the protrusion is disposed to support the anode current collecting plate 5 to prevent the center of the anode end from being suspended, and the winding core 2 presses and deforms the anode current collecting plate 5 to affect the contact of the periphery thereof with the case 1, thereby affecting the laser welding of the periphery of the case 1 and the anode current collecting plate 5.

In an alternative embodiment, the housing 1 has opposite first and second ends, the first end of the housing 1 being attached to the second disc 51 and the second end of the housing 1 being attached to the cover plate 42.

Specifically, in order to realize that the positive pole and the negative pole of lithium cell are arranged with the same side, make things convenient for the design and the preparation of battery module, can regard apron 42 as the negative pole end, lie in the book core 2 negative pole of casing 1 bottom promptly and pass through casing 1 and be connected with apron 42, its concrete implementation does, casing 1 has relative first end and second end, wherein first end is the bottom of casing 1, the second end is the top of casing, as shown in fig. 5, the top of casing 1 is buckled and is extended to and is connected with apron 42 to carry out laser welding at the junction.

In view of facilitating the welding of the case 1 and the cap plate 42, as shown in fig. 5, a groove may be provided on the cap plate 42, and both are laser welded at the groove.

In addition, the edge of the bottom of the shell 1 can be provided with a notch to enhance the explosion-proof capability of the lithium battery, and the notch can be a C-shaped notch, and the cross section of the notch can also be a V-shaped notch, a single V-shaped notch or other shapes.

In a second aspect, an embodiment of the present invention provides a method for preparing a lithium battery, including:

and step 1, performing laser welding on the anode of the winding core and the anode current collecting disc.

And 2, performing laser welding on the cathode of the winding core and the cathode current collecting disc.

And step 3, assembling the insulating ring and the positive current collecting disc.

And 4, putting the winding core into the shell, and performing a rolling groove process.

And 5, assembling the cover body assembly to the positive electrode side of the winding core.

And 6, performing laser welding on the contact part of the top of the shell and the cover body assembly.

And 7, performing laser welding on the contact position of the bottom surface of the shell and the negative current collecting disc.

Specifically, a positive electrode plate is manufactured: lithium iron phosphate, a conductive agent and a binder are mixed according to a certain proportion to prepare slurry, and the slurry is coated on the aluminum foil of the positive current collector in a stripe coating mode, and 4 strips are coated in total. And reserving 7.5mm empty foil areas on two sides of the aluminum foil, reserving 15mm empty foil areas on 3 middle strips of the aluminum foil, rolling after drying, and rolling and slitting to finish the anode sheet making.

Manufacturing a positive current collecting plate 3: the positive electrode current collecting plate 3 is a carbon-coated aluminum foil with the thickness of 15 mu m, the width is 652mm, and the coating surface density is 41.5mg/cm ² After rolling, the thickness is 195 μm, and the rolled sheet is cut into 8 pole pieces, each having a width of 81.5 mm.

Manufacturing a negative plate: mixing artificial graphite, a conductive agent and a binder according to a certain proportion to prepare slurry, coating the slurry on a copper foil of a negative current collector in a stripe coating mode, coating 4 strips of the slurry, reserving 4.5mm empty foil areas on two sides of the copper foil, reserving 9mm empty foil areas on 3 strips in the middle of the copper foil, drying, rolling and slitting to finish negative electrode sheet preparation.

Manufacturing an anode current collecting plate 5: the negative electrode current collecting plate 5 is a copper foil of 8 μm, width is 652mm, and coating surface density is 19.5mg/cm ² And the rolled thickness is 125 mu m, and the rolled thickness is cut into 8 pole pieces, and the width of each pole piece is 81.5 mm.

Preparing a diaphragm: a separator having a width of 80mm was fabricated using a polyethylene film having a 3 μm ceramic coating layer coated on one surface thereof and a total thickness of 12 μm.

Preparing a roll core 2: and winding the slit positive plate, the slit negative plate and the diaphragm into a winding core 2 to obtain the winding core 2 with the diameter of 41.2 mm. The anode and cathode empty foils are required to be arranged on two sides of the winding core 2, the ceramic surface of the diaphragm faces to the cathode, the diaphragm wraps the cathode material area, and the cathode material area wraps the anode material area.

Kneading and flattening: and flattening the winding core 2, flattening the positive electrode and the negative electrode by adopting ultrasonic, flattening by using a machine, flattening the positive electrode by 2mm, flattening the negative electrode by 1.5mm, and flattening to obtain the total height of 84 mm.

Welding the end face of the positive electrode: assembling the anode of the flat rolled core 2 and an anode current collecting disc 3, wherein the current collecting disc protrudes outwards to ensure the assembly concentricity, and meanwhile, the current collecting disc is tightly contacted with the pole piece, and then, performing laser welding on the groove of the current collecting disc.

Welding the end face of the negative electrode: assembling the cathode of the flat rolled core 2 and a cathode current collecting disc 5, wherein the current collecting disc protrudes outwards to ensure the assembly concentricity, and meanwhile, the current collecting disc is tightly contacted with the pole piece, and then, laser welding is carried out on the groove of the current collecting disc.

The insulating ring 6 is assembled with the positive current collecting plate 3.

Roll up 2 income shells of core, welding and slot rolling: the negative pole of the winding core 2 is downwards arranged in the shell 1, and laser welding is carried out from the groove on the bottom surface of the shell 1. The shell 1 is required to have no over-welding breakdown, after the shell is turned, the winding core 2 cannot fall from the shell 1, and after the shell is qualified, the rolling groove is performed. The lid assembly 4 is assembled to the positive electrode side of the winding core 2, the mouth of the case 1 is pressed down using equipment, the opening is sealed along the groove shape on the lid plate 42, and the contact portion between the case mouth and the groove is laser-welded.

And (3) air tightness detection: helium is injected from the cap hole, and the battery sealing laser welding and shell bottom laser penetration welding positions are subjected to tightness detection by using helium detection equipment.

Battery liquid injection: the battery was first filled through the through-hole of the rivet 41 in an amount of 10 g.

Battery pre-formation: and (4) blocking the liquid injection hole by using a rubber plug, performing a pre-formation process on the battery, and discharging gas generated by the battery from the liquid injection hole.

And (4) secondary liquid injection: and (5) removing the rubber plug, carrying out secondary electrolyte injection on the battery, wherein the electrolyte injection amount is 40g, and filling helium gas from the electrolyte injection hole.

And (3) a sealing procedure: the inner hole formed by the first bulge 32 on the positive current collecting plate 3 is shaped and expanded by equipment, the sealing nail 44 is pressed in, and then the joint is welded by laser to seal.

And (3) sealing detection: and (4) using helium detection equipment to detect the tightness of the liquid injection hole.

Cleaning and drying the battery: firstly pouring UV glue into the grooves of the cap, curing the UV glue through an ultraviolet lamp, then inverting the battery, pouring UV glue into the grooves at the bottom of the steel shell, curing the UV glue through the ultraviolet lamp, and finally oiling, thermally shrinking and code spraying the battery to complete the manufacturing, so that the cylindrical lithium battery is obtained.

And finally, carrying out other procedures such as formation, capacity grading and the like on the lithium battery.

The lithium battery manufactured by adopting the structure and the process has the single capacity of 15Ah, the internal resistance of less than or equal to 1.5m omega, and the temperature rise of the 4C charging and discharging is less than 30 ℃.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A lithium battery, comprising: the device comprises a shell, a winding core, a positive current collecting disc, an insulating ring and a cover body assembly;

the cover body assembly comprises a rivet, a cover plate, an insulation assembly and a sealing nail, the rivet is provided with a first through hole, and the first bulge is attached to the inner wall surface of the first through hole; the cover plate covers the opening, and the cover plate is connected with the insulating ring and the rivet through the insulating assembly; the sealing nail is embedded in the first through hole and attached to the first protrusion.

2. The lithium battery of claim 1, wherein the sealing nail is provided with a first chamfer at the intersection of the sealing nail, the first protrusion and the rivet, and/or wherein the rivet is provided with a second chamfer at the intersection of the sealing nail, the first protrusion and the rivet.

3. The lithium battery of claim 1, wherein the positive current collector further comprises a first groove formed by pressing and recessing from an end surface of the first tray body toward the positive electrode of the winding core, and the positive current collector is welded to the positive electrode of the winding core through the first groove.

4. The lithium battery according to claim 3, wherein in a case where the first groove is plural, the plural first grooves are arranged in order in a circumferential direction of the first tray body.

5. The lithium battery of claim 4, wherein the positive current collecting plate further comprises a second through hole, and the second through hole is provided between two adjacent first grooves.

6. The lithium battery of claim 1, wherein the insulating assembly includes a first insulating member sandwiched between the cover plate and the insulating collar and a second insulating member sandwiched between the rivet and the cover plate.

7. The lithium battery of claim 1, further comprising an anode current collecting tray, wherein the anode current collecting tray comprises a second tray body and a second groove, the second groove is formed by pressing and sinking from an end face of the second tray body toward the anode of the winding core, and the anode current collecting tray is connected with the anode of the winding core through the second groove.

8. The lithium battery of claim 7, wherein the housing has opposite first and second ends, the first end of the housing being attached to the second tray and the second end of the housing being attached to the cover.

9. A method of manufacturing a lithium battery as claimed in any one of claims 1 to 8, characterized in that it comprises:

laser welding the positive electrode of the winding core and the positive electrode current collecting disc; laser welding the negative electrode of the winding core and the negative electrode current collecting disc;

assembling an insulating ring and the positive current collecting disc;

putting the winding core into a shell, and performing a rolling groove process;

assembling a cover assembly to the positive side of the winding core;

10. The method for manufacturing a lithium battery according to claim 9, wherein the assembling of the cover assembly to the positive electrode side of the winding core is specifically:

assembling a cover plate on the positive side of the winding core;