阅读说明：本技术 锂电池的多卷芯并联装配方法 (Multi-winding-core parallel assembly method of lithium battery ) 是由 高冲 程辉 吴德 于 2020-12-17 设计创作，主要内容包括：本发明公开锂电池的多卷芯并联装配方法,包括以下步骤：步骤S1：多个单卷芯焊接在连接片；后将多个单卷芯依次合芯,并通过绝缘带包裹焊接区域；其中,每个所述连接片包括与单卷芯相等个数的极耳连接部、至少一个导电连接部,导电连接部连接在极耳连接部的顶部并延伸至极耳连接部的一侧或两侧,将多个单卷芯并排布置,将多个单卷芯的极耳与极耳连接部焊接；步骤S2：将合芯后的卷芯组与盖板组件连接。本发明的有益效果：可以根据需要选择任意数量的卷芯进行连接,使用灵活；降低了锂电池制造的短路率、结构更加紧凑,从而能有效提升整个锂电池的能量密度。(The invention discloses a multi-winding-core parallel assembly method of a lithium battery, which comprises the following steps of: step S1: a plurality of single winding cores are welded on the connecting sheet; then, sequentially combining the single winding cores, and wrapping the welding area by an insulating tape; each connecting piece comprises tab connecting parts and at least one conductive connecting part, the number of the tab connecting parts is equal to that of the single winding cores, the conductive connecting parts are connected to the tops of the tab connecting parts and extend to one side or two sides of the tab connecting parts, the single winding cores are arranged side by side, and tabs of the single winding cores are welded with the tab connecting parts; step S2: and connecting the combined winding core group with the cover plate component. The invention has the beneficial effects that: any number of winding cores can be selected to be connected according to the requirement, and the use is flexible; the short circuit rate of lithium battery manufacture is reduced, the structure is more compact, and therefore the energy density of the whole lithium battery can be effectively improved.)

1. The multi-winding core parallel assembly method of the lithium battery is characterized by comprising the following steps of:

step S1: a plurality of single winding cores are welded on the connecting sheet; then, sequentially combining the single winding cores, and wrapping the welding area by an insulating tape;

each connecting piece comprises tab connecting parts and at least one conductive connecting part, the number of the tab connecting parts is equal to that of the single winding cores, the conductive connecting parts are connected to the tops of the tab connecting parts and extend to one side or two sides of the tab connecting parts, the single winding cores are arranged side by side, and tabs of the single winding cores are welded with the tab connecting parts;

step S2: connecting the combined winding core group with the cover plate assembly;

wherein, the cover plate component comprises a conducting strip, and the conducting connecting part is welded with the conducting strip.

2. The method of claim 1, wherein in the step S1, the tabs of the two single winding cores are welded to the tab connection portion and combined to form a dual winding core, and then the tabs of the third single winding core are welded to the tab welding portion and combined to the dual winding core, and if the number of the single winding cores is greater than three, the welding and combining of the tabs of the third single winding core are performed sequentially.

3. The method of assembling multiple jelly rolls of a lithium battery according to claim 1, wherein in the step S1, if the number of the single jelly rolls is an even number, two single jelly rolls are welded and combined with the connecting sheet to form a double jelly roll, and then a plurality of groups of the double jelly rolls are connected side by side to form an even number of jelly roll groups.

4. The method of assembling multiple coils of lithium battery in parallel as claimed in claim 2 or 3, wherein the double coil core is formed by arranging two single coil cores in a mirror image, overlapping the tabs of the two single coil cores on two connecting sheets, and placing the protective sheet on the tabs, and welding to form a weld; after core combination, the two single-roll cores are bonded together by adhesive tape and are bonded by adhesive tape in the welding area.

5. The method of claim 1, wherein the connecting plate is an integrally formed plate structure, the tab connecting portion and the conductive connecting portion are T-shaped or single-sided T-shaped structures, the conductive connecting portion is disposed at two ends of a top of the T-shaped or single-sided T-shaped structure, and the tab connecting portion is disposed at a bottom of the T-shaped or single-sided T-shaped structure.

6. The method of assembling a lithium battery in parallel with multiple lithium battery cores as claimed in claim 5, wherein a first groove is formed between adjacent ones of the tab connection parts, and a second groove is formed between the conductive connection parts.

7. The method of claim 6, wherein the cover plate assembly further comprises a base plate, an insulating plate, a first pole, a second pole, and a boss, wherein the first pole and the second pole are respectively connected to the top surface of the base plate, the insulating plate is connected to the bottom surface of the base plate, the conductive plates are connected to the insulating plate, the first pole is connected to one of the conductive plates through the boss, and the second pole is connected to the other conductive plate through the boss.

8. The method of claim 7, wherein the insulating plate has a flange on a side of a bottom surface thereof, the flange has a notch, the conductive plate is connected to the notch, and the base plate, the conductive plate and the boss are made of metal.

9. The method as claimed in claim 7, wherein the substrate and the insulating plate have holes for passing the bosses, one end of the boss after passing the holes is fixedly connected with the first pole and the second pole, the other end of the boss is fixedly connected with the conductive sheet, the polarities of the first pole and the second pole are different, and the insulating members are arranged between the first pole, the second pole and the substrate.

10. The multi-core parallel assembly method of a lithium battery as claimed in claim 1, further comprising the step S3: covering the conductive connecting part welded in the step S2 and the welding and printing surface of the conductive sheet with an adhesive tape; the welded conductive connecting part and the conductive sheet are folded together, so that the conductive connecting part is tightly attached to the outer surface of the single winding core; and sticking an adhesive tape on the outer surface of the conducting strip.

Technical Field

The invention relates to the technical field of lithium batteries, in particular to a multi-winding-core parallel assembly method of a lithium battery.

Background

The assembly of rolling up the core of present power lithium cell adopts two book core butterfly welding process more, like the application number: 201721484494.0, background art in a butterfly welding clamp for assembling lithium battery electric core: the tabs a1 of the two winding cores a are prewelded by an ultrasonic welding machine respectively; after the two winding cores a are paired, welding a tab a1, a gasket a2 and a soft connecting sheet a3 together by using an ultrasonic welding machine; welding the gasket a2 and the cover plate a4 together by using a laser welding machine; the two cores are combined and then taped with tape a5, a process also known as butterfly welding.

However, this process requires that the spacing between the jelly rolls be greater than the width of the cover sheet, which results in an excessively long tab for the jelly roll. After the double-winding core is combined, the tabs of the winding core are folded, so that the tabs are in contact with the pole piece inside the winding core and the external aluminum shell, and the risk of short circuit of the lithium battery is greatly increased; and the overlong pole lug also increases the using amount of foil, and the material cost of manufacture is improved.

In traditional two core butterfly welding process that roll up, connection piece and apron are accomplished through laser welding, but the welding point is located the central part of two roll core intervals, and the opening part towards rolling up the core promptly, this will lead to among the welding process, and metal dust very easily gets into the inside of rolling up the core to greatly increased the risk of rolling up the core short circuit.

In traditional two core butterfly welding process that roll up, after two core that roll up closed the core, the clearance between apron and the core that rolls up is great, and the inner space of unable make full use of aluminum hull to lithium cell energy density's promotion has been restricted.

Aiming at the parallel assembly of multiple winding cores, the traditional winding core assembly mode cannot be compatible with the assembly of any multiple winding core, so that the wide application of the lithium battery technology is limited.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: how to solve the problem that the existing assembly method of the winding core cannot be compatible with the assembly of any winding cores.

The invention solves the technical problems through the following technical means:

the multi-winding-core parallel assembly method of the lithium battery comprises the following steps:

step S1: a plurality of single winding cores are welded on the connecting sheet; then, sequentially combining the single winding cores, and wrapping the welding area by an insulating tape;

each connecting piece comprises tab connecting parts and at least one conductive connecting part, the number of the tab connecting parts is equal to that of the single winding cores, the conductive connecting parts are connected to the tops of the tab connecting parts and extend to one side or two sides of the tab connecting parts, the single winding cores are arranged side by side, and tabs of the single winding cores are welded with the tab connecting parts;

step S2: connecting the combined winding core group with the cover plate assembly;

wherein, the cover plate component comprises a conducting strip, and the conducting connecting part is welded with the conducting strip.

According to the invention, the plurality of winding cores are welded and combined in sequence through the connecting sheets, so that the assembly of the plurality of winding cores is realized, any number of winding cores can be selected to be connected according to the requirement, and the use is flexible; and the conductive connecting part of the connecting sheet is contacted with the conductive sheet of the cover plate assembly, and the welding points are all positioned at the outer side of the core after the core is combined by the winding core, so that the purpose of reducing the welding short circuit rate is realized.

Preferably, in step S1, the tabs of the two single-winding cores are welded to the tab connection portions, and the two single-winding cores are combined to form a double-winding core, and then the tabs of the third single-winding core are welded to the tab welding portions, and the double-winding core is combined with the tab welding portions, if the number of the single-winding cores is greater than three, the welding and core combining manner of the third single-winding core is performed in sequence.

Preferably, in step S1, if the number of the single winding cores is even, two single winding cores and the connecting sheet are welded and combined to form a double winding core, and then the multiple groups of double winding cores are connected side by side to form an even number of winding core groups.

Preferably, the specific process of forming the double-winding core is to arrange the two single-winding cores in a mirror image manner, lap the tabs of the two single-winding cores on the two connecting sheets, place the protective sheets on the tabs, and weld to form a welding mark; after core combination, the two single-roll cores are bonded together by adhesive tape and are bonded by adhesive tape in the welding area.

Preferably, the connecting sheet is of an integrally formed sheet structure, the tab connecting portion and the conductive connecting portion are of a T-shaped or single-side T-shaped structure, the conductive connecting portion is arranged at two ends of the top of the T-shaped or single-side T-shaped structure, and the tab connecting portion is arranged at the bottom of the T-shaped or single-side T-shaped structure.

Preferably, a first groove is formed between the adjacent tab connecting parts, and a second groove is formed between the conductive connecting parts.

Through set up first recess, second recess, keep modes such as unilateral T type weld part on the connection piece, realized further reducing connection piece quality, promote lithium cell energy density's purpose.

Preferably, the cover plate assembly further comprises a base plate, an insulating plate, a first pole, a second pole and a boss, the first pole and the second pole are respectively connected to the top surface of the base plate, the insulating plate is connected to the bottom surface of the base plate, the conducting strips are connected to the insulating plate, the first pole is connected to one of the conducting strips through the boss, and the second pole is connected to the other conducting strip through the boss.

Preferably, the side edge of the bottom surface of the insulating plate is provided with a flange, the flange is provided with a notch, the conducting strip is connected at the notch, and the base plate, the conducting strip and the boss are all made of metal materials.

Preferably, the base plate with the hole that supplies the boss to pass has on the insulation board, the boss links firmly first utmost point post and second utmost point post through the one end behind the hole, and the other end links firmly the conducting strip, and the polarity of first utmost point post and second utmost point post is different, separates between first utmost point post, second utmost point post and the base plate and has the insulating part.

Preferably, the method further comprises step S3: covering the conductive connecting part welded in the step S2 and the welding and printing surface of the conductive sheet with an adhesive tape; the welded conductive connecting part and the conductive sheet are folded together, so that the conductive connecting part is tightly attached to the outer surface of the single winding core; and sticking an adhesive tape on the outer surface of the conducting strip.

The invention uses the adhesive tape to cover the welding area for many times, thereby preventing welding dust from entering the inside of the winding core and avoiding short circuit.

The invention has the advantages that:

(1) according to the invention, the plurality of winding cores are welded and combined in sequence through the connecting sheets, so that the assembly of the plurality of winding cores is realized, any number of winding cores can be selected to be connected according to the requirement, and the use is flexible; compared with the traditional butterfly welding assembly mode, the method has the advantages that the shorter tabs can be adopted, the risks of tab folding and short circuit of the battery cell due to overlong tabs can be avoided, the material cost can be effectively reduced, and the energy density of the lithium battery can be improved; compared with the traditional butterfly welding assembly mode, the final welding seal is positioned on the outer side of the core after the core is combined with the winding core, so that the risk that welding dust enters the inside of the winding core can be effectively avoided, and the short circuit rate of lithium battery manufacturing is reduced; compared with the traditional assembly mode, the invention can effectively reduce the gap between the winding core and the cover plate, so that the structure of the parallel winding core is more compact, and the energy density of the whole lithium battery can be effectively improved;

(2) the connecting piece is provided with the first groove and the second groove, the single-side T-shaped welding part is reserved, and the like, so that the aims of further reducing the quality of the connecting piece and improving the energy density of the lithium battery are fulfilled;

(3) adopt the sticky tape cladding to live welding area, play and prevent that the welding dust from getting into roll up the core inside, avoid the effect of short circuit.

Drawings

FIG. 1 is a top view of a dual core coil after welding in accordance with one embodiment of the present invention;

FIG. 2 is a front view of a dual core spool after welding according to one embodiment of the present invention;

FIG. 3 is a back view of a dual-core weld in accordance with one embodiment of the present invention;

FIG. 4 is a three-dimensional view of a dual-core weld in accordance with one embodiment of the present invention;

FIG. 5 is a three-dimensional view of a dual-core assembly according to a first embodiment of the present invention;

FIG. 6 is a partial schematic view of a dual-core assembly according to an embodiment of the present invention;

FIG. 7 is a three-dimensional view of a double-core embodiment of the present invention after being glued;

FIG. 8 is a top view of a cover plate assembly according to one embodiment of the present invention;

FIG. 9 is a rear elevational view of a cover plate assembly in accordance with one embodiment of the present invention;

FIG. 10 is a three-dimensional view of a cover plate assembly according to an embodiment of the present invention;

FIG. 11 is a cross-sectional view of the cover plate assembly of FIG. 8 taken at A-A;

FIG. 12 is a schematic view of a dual roll core assembled to a cover assembly in accordance with one embodiment of the present invention;

FIG. 13 is a top view of FIG. 12 after welding;

FIG. 14 is an enlarged view of a portion of the tape applied in FIG. 13;

FIG. 15 is an enlarged partial view of the folding carried out on the basis of FIG. 14;

FIG. 16 is an enlarged partial view of the folded portion of FIG. 15;

FIG. 17 is a schematic structural view of a connecting piece in the second embodiment of the present invention;

FIG. 18 is a three-dimensional view of a double-core weld of a second embodiment of the present invention;

FIG. 19 is a schematic structural view of a connecting piece in the third embodiment of the present invention;

FIG. 20 is a three-dimensional view of a double-core coil after welding in accordance with a third embodiment of the present invention;

FIG. 21 is a schematic structural view of a connecting piece in the fourth embodiment of the present invention;

FIG. 22 is a three-dimensional view of a dual-core weld of a fourth embodiment of the present invention;

FIG. 23 is a top view of a fourth embodiment of the present invention after welding with three jelly rolls;

FIG. 24 is a front view of a four-core embodiment of the present invention after welding;

FIG. 25 is a three dimensional view of a three core weld of a fourth embodiment of the present invention;

FIG. 26 is a back view of a four-core embodiment of the present invention after welding;

FIG. 27 is a three-dimensional view of a three-core post-lamination adhesive according to a fourth embodiment of the present invention;

FIG. 28 is a three-dimensional view of a fifth core of an embodiment of the present invention after welding;

FIG. 29 is a three-dimensional view of a six-coil core of the present invention after welding;

FIG. 30 is a three-dimensional view of a four-core laminated post-lamination adhesive in a sixth embodiment of the present invention.

Reference numerals: 100. a single roll core; 101. a roll core body; 102. a first tab; 103. a second tab; 104. primary welding and printing;

200. connecting sheets; 201. a conductive connection portion; 202. a tab connecting part; 203. a first groove; 204. a second groove;

300. a protective sheet;

400. an adhesive tape;

500. a cover plate assembly; 501. a first pole column; 502. a second pole; 503. a substrate; 504. an insulating plate; 505. a conductive sheet; 506. a boss; 507. final welding and printing;

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. 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 first embodiment is as follows:

as shown in fig. 1, fig. 2, fig. 3 and fig. 4, the method for assembling multiple winding cores of a lithium battery in parallel, the embodiment discloses a parallel method of double winding cores; the method comprises the following steps:

step S1: the single winding core 100 comprises a winding core body 101, and a first tab 102 and a second tab 103 which are arranged on the winding core body 101; the connecting sheet 200 is a T-shaped structure, the T-shaped structure is an integrated sheet structure, two ends of a first of the T-shaped structure are conductive connecting portions 201, and a first of the T-shaped structure is provided with two tab connecting portions 202, in fig. 3, a dashed line frame is used for illustration, and actually the two tab connecting portions 202 are connected together;

the two single winding cores 100 are respectively arranged in a mirror image mode, and the polar ears on the same side are the same in polarity. The first tab 102 and the second tab 103 are respectively placed on the connecting sheet 200, the protective sheet 300 is respectively placed on the first tab 102 and the second tab 103, and finally the connecting sheet 200, the first tab 102, the second tab 103 and the protective sheet 300 are welded, as shown in fig. 4, and the primary welding mark 104 is obtained. Can utilize sticky tape 400 cladding to live whole welding area, play and prevent that the welding dust from getting into roll up the core inside, avoid the effect of short circuit. Ultrasonic welding can be adopted, but the embodiment does not limit the specific welding mode;

as shown in fig. 5 and 6, the two single-roll cores 100 are combined, and as shown in fig. 7, the two single-roll cores 100 are fixed by an adhesive tape 400.

Step S2: connecting the core after core combination with the cover plate assembly 500;

as shown in fig. 8, 9, 10, and 11, the cover plate assembly 500 includes a first pole column 501, a second pole column 502, a base plate 503, an insulating plate 504, a conductive sheet 505, and a boss 506;

as shown in fig. 8 and 9, the first pole column 501 and the second pole column 502 are respectively connected to the top surface of the substrate 503, the first pole column 501 and the second pole column 502 have different polarities, an insulating member is interposed between the first pole column 501, the second pole column 502, and the substrate 503, the insulating plate 504 is connected to the bottom surface of the substrate 503, and the conductive sheet 505 is connected to the insulating plate 504.

As shown in fig. 10, the insulating plate 504 has a flange on the bottom side, the flange has a notch, the conductive sheet 505 is connected at the notch, two ends of the conductive sheet 505 are used for connecting with the conductive connecting part 201, and some weight-reducing slots may be provided in the middle for reducing weight; the substrate 503, the conductive sheet 505 and the boss 506 are all made of metal.

As shown in fig. 11, the base plate 503 and the insulating plate 504 have holes for passing through the bosses 506, and after the bosses 506 pass through the holes, one end of the bosses is fixedly connected with the first pole column 501 and the second pole column 502, and the other end of the bosses is fixedly connected with the conductive sheet 505.

As shown in fig. 12 and 13, the double-rolled core after the core combination in step S1 is assembled on the cover plate assembly 500, the connecting sheet 200 is firstly contacted with the conductive sheet 505, and then the two are respectively welded together to obtain a final welding mark 507, which can be a laser welding method, but the invention is not limited to a specific welding method;

step S3: covering the surface of the conductive connection part 201 and the solder mark 507 of the conductive sheet 505 which are welded in the step S2 with an adhesive tape 400 as shown in fig. 14; the conductive connection part 201 welded as shown in fig. 15 is folded by 90 degrees together with the conductive sheet 505, so that the conductive connection part 201 is closely attached to the outer surface of the single-core 100; the adhesive tape 400 is attached to the outer surface of the conductive sheet 505, so that dust is prevented from being diffused into the winding core;

as shown in fig. 16, on the basis of fig. 15, an adhesive tape 400 is attached to the outer surface of the conductive sheet 505 to prevent the conductive sheet 505 from contacting the aluminum case, thereby avoiding the risk of short circuit of the battery.

At this point, the process of assembling the double winding cores in parallel in the first embodiment is completed.

Example two:

as shown in fig. 17, the present embodiment is different from the first embodiment in that: the connecting sheet 200 is different in structure;

a first groove 203 is formed between the adjacent tab connection parts 202, the first groove 203 separates the tab connection parts 202, and a second groove 204 is formed between the conductive connection parts 201. The connecting piece 200 is provided with the first groove 203 and the second groove 204, so that the aims of further reducing the quality of the connecting piece 200 and improving the energy density of the lithium battery are fulfilled.

As shown in fig. 18, the two tab connection portions 202 are welded to the first tab 102 and the second tab 103 of the two single cores 100, respectively.

Example three:

as shown in fig. 19, the present embodiment is different from the second embodiment in that: leaving only one side conductive connection 201;

leaving only one side of the conductive connection 201 may further reduce the mass of the tab 200. It should be noted that, in this case, the cover plate assembly 500 also needs to be changed accordingly: the conductive sheet 505 also has only one bonding position left, and the position corresponds to the conductive connection portion 201 of the connection sheet 200.

As shown in fig. 20, two tab connection portions 202 are respectively welded to the first tab 102 and the second tab 103 of the two single-winding cores 100, and the conductive connection portions 201 of the two connection pieces 200 are respectively disposed on two sides of the winding core after core combination.

Example four:

as shown in fig. 21, the present embodiment is different from the first embodiment in that: assembling three single winding cores 100 in parallel;

in the connecting sheet 200 of the present embodiment, a first groove 203 is formed between adjacent tab connecting portions 202, the first groove 203 separates the tab connecting portions 202, and a second groove 204 is formed between the conductive connecting portions 201; in this embodiment, there are three tab connection portions 202, and two conductive connection portions 201;

as shown in fig. 22, firstly, according to step S1 in the first embodiment, the welding of the double winding cores is implemented, the tabs of two single winding cores 100 are welded to two adjacent tab connection portions 202, as shown in fig. 23 to 27, then one single winding core 100 is welded to the remaining tab connection portion 202, the welding manner is the same as that in the first embodiment, and finally, the three single winding cores 100 are fixed by the adhesive tape 400.

By analogy, if the number of the single winding cores 100 is more than three, the tab connecting part 202 is added to the matched connecting sheet 200; and sequentially according to the welding core combination mode of the third single-core 100.

Example five:

as shown in fig. 28, the present embodiment is different from the fourth embodiment in that: the connecting sheet 200 retains a conductive connecting portion 201 on one side;

and the conductive connection portions 201 of the two connection pads 200 may be oriented in the same direction or in opposite directions (as shown in fig. 28, the conductive connection portions 201 of the two connection pads 200 are oriented in opposite directions). It should be noted that, in this case, the conductive sheet 505 of the cover plate assembly 500 also needs to be changed accordingly, and only one side of the conductive sheet 505 is kept at the soldering portion corresponding to the soldering portion of the conductive connection portion 201.

Example six:

the difference between this embodiment and the first embodiment is: four single winding cores 100 are assembled in parallel;

the dual roll core configuration shown in fig. 29: firstly, welding the lugs of two single-winding cores 100 on the lug connecting parts 202 in the manner of step S1 in the first embodiment, wherein the connecting piece 200 in the third embodiment is the connecting piece 200 (or is symmetrical to the third embodiment), and the lug connecting parts 202 of the two connecting pieces 200 are in the same orientation; repeating the above process to obtain the double-winding core structure mirrored with fig. 29, wherein the difference between the double-winding core structure shown in fig. 29 and the mirrored double-winding core structure is as follows: the directions of the welding parts of the connecting sheets 200 are different;

as shown in fig. 30, two mirror image dual-core structures are butted and bonded together using tape 400; and then connected to the cover plate assembly 500.

It should be noted that, in the above embodiments, only different parts are described, and the rest of the embodiments are in the same manner as in the first embodiment, or some adaptive adjustments are made, which are not described again.

And the preferred embodiment that is applicable to two book cores, three book cores, four book core parallel assembly has been given in above-mentioned embodiment, can know from this, through arbitrary combination, this application can be compatible arbitrary many book cores's parallel assembly, has promoted technology adaptability greatly.

According to the invention, the plurality of single winding cores 100 are sequentially welded and combined through the connecting sheet 200, so that the assembly of the plurality of winding cores is realized, any number of winding cores can be selected to be connected according to the requirement, and the use is flexible; and the conductive connecting part 201 of the connecting sheet 200 is contacted with the conductive sheet 505 of the cover plate assembly 500, and the welding points are positioned at the outer side of the core after the core is combined by the winding core, so that the purpose of reducing the welding short circuit rate is realized.

The application can adopt shorter tabs, not only can avoid the risks of tab folding and cell short circuit caused by overlong tabs be avoided, but also the material cost can be effectively reduced, and the energy density of the lithium battery can be improved; the final welding prints are located on the outer side of the core-wound core after the core is combined, so that the risk that welding dust enters the core-wound core can be effectively avoided, and the short circuit rate of lithium battery manufacturing is reduced; the gap between the roll core and the cover plate can be effectively reduced, the structure of the roll core connected in parallel is more compact, and therefore the energy density of the whole lithium battery can be effectively improved.

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.