阅读说明：本技术 一种电芯热复合制成工艺 (Cell thermal compounding manufacturing process ) 是由 宾兴 刘成 彭强 唐延第 徐骏 谭振涛 于 2021-11-11 设计创作，主要内容包括：本发明公开了一种电芯热复合制成工艺,包括如下工艺步骤：极片制成：带状结构的极片带经极耳成型、极片裁切后形成单片状的极片；极片制袋：单片状的第一极片或第二极片经两侧的隔膜分别热复合粘合在正反两侧壁,正反侧隔膜延伸至第一极片或第二极片的外侧后相互粘合形成连续极片袋,并经裁切制成单极片袋；电芯制成：单极片与单极片袋相互交错叠合形成电芯。本发明解决了隔膜起皱问题,保证了正负极片之间位置精度,采用大于极片尺寸的隔膜将传统叠片的单隔膜对位工序简化掉,有效地提高了叠片效率,且减少了短路易燃情况,提高了电池安全系数。(The invention discloses a process for manufacturing a battery cell by thermal compounding, which comprises the following process steps: the pole piece is made: forming a pole piece strip with a strip-shaped structure through a pole lug, and cutting the pole piece to form a single-sheet pole piece; pole piece bag making: the single-sheet first pole piece or the single-sheet second pole piece is respectively bonded on the front side wall and the back side wall in a thermal compounding way through diaphragms on the two sides, the diaphragms on the front side and the back side extend to the outer side of the first pole piece or the second pole piece and are bonded with each other to form a continuous pole piece bag, and the continuous pole piece bag is cut into the single-sheet bag; preparing a battery core: the single pole piece and the single pole piece bag are mutually staggered and overlapped to form the battery core. The invention solves the diaphragm wrinkling problem, ensures the position precision between the positive and negative pole pieces, simplifies the single diaphragm contraposition process of the traditional lamination by adopting the diaphragm larger than the size of the pole pieces, effectively improves the lamination efficiency, reduces the short circuit and flammability condition and improves the safety coefficient of the battery.)

1. A cell thermal compounding manufacturing process is characterized by comprising the following process steps:

s1, manufacturing a first pole piece: forming a first pole piece belt of a belt-shaped structure through a pole lug, and cutting the pole piece to form a single-piece first pole piece;

s2, preparing a second pole piece: forming a second pole piece belt of a belt-shaped structure with the polarity opposite to that of the first pole piece in the step S1 through a pole lug, and cutting the pole piece to form a second pole piece in a single sheet shape;

s3, pole piece bag making: in the process of linear transmission of the first or second single-sheet pole piece in the step S1 or S2, the front and back sides of the first or second pole piece are synchronously covered with strip-shaped diaphragms, the diaphragms on the two sides are respectively bonded with the front and back side walls of the first or second pole piece in a thermal compounding manner, the diaphragms on the front and back sides extend to the outer side of the first or second pole piece and are bonded with each other to form a continuous pole piece bag wrapping the first or second pole piece, and the continuous pole piece bag is cut into single pole piece bags;

s4, preparing a battery cell: when the first pole piece is used for making the bag in the step S3, the second pole piece in the step S2 and the single pole piece bag in the step S3 are overlapped in a staggered mode to form a battery cell; when the second pole piece is used for making the pouch in step S3, the first pole piece in step S1 and the single pole piece pouch in step S3 are overlapped in an interlaced manner to form a battery cell.

2. The process for thermally compounding and manufacturing the battery cell according to claim 1, wherein: the first pole piece in the step S1 is a positive pole piece, and the process in the step S1 sequentially comprises the steps of unwinding and deviation rectifying of the positive pole piece, tension caching, process deviation rectifying, die forming of a pole lug, CCD detection of the size of the pole lug, die cutting of the pole lug into a piece, CCD detection of the pole piece, anode piece blanking and anode piece caching.

3. The process for thermally compounding and manufacturing the battery cell according to claim 1, wherein: the second pole piece in the step S2 is a negative pole piece, and the process in the step S2 sequentially comprises the steps of unwinding and deviation rectifying of the negative pole piece, tension caching, process deviation rectifying, laser forming of the pole lug, CCD detection of the size of the pole lug, laser cutting of the pole piece, dust removal of the pole piece and CCD detection of the size of the pole piece.

4. The process for thermally compounding and manufacturing the battery cell according to claim 1, wherein: the pole piece bag making in the step S3 is a negative pole piece, and the process in the step S3 sequentially comprises the steps of pole piece and diaphragm compounding, pole piece and diaphragm protection film entering, pole piece preheating, pole piece hot pressing, pole piece short circuit testing, diaphragm size detection by a CCD (charge coupled device), diaphragm cutting by a die, cathode pole piece bag blanking and cathode pole piece bag caching.

5. The process for thermally compounding and manufacturing the battery cell according to claim 4, wherein: in the step S3, two sides of the monolithic negative electrode sheet (A1) which is linearly and horizontally conveyed forwards are respectively provided with a diaphragm material roll (1), and diaphragms (2) on the diaphragm material rolls (1) are respectively pulled out along the conveying direction of the monolithic negative electrode sheet (A1) and pass through hot pressing rollers (5) symmetrically arranged at two sides of the monolithic negative electrode sheet (A1).

6. The process for thermally compounding and manufacturing the battery cell according to claim 5, wherein: the two sides of the monolithic negative electrode sheet (A1) are respectively provided with a protective film material roll (3), a tensioning roll (7) and a material receiving roll (8), a protective film (4) pulled out by the protective film material roll (3) covers the surface of the diaphragm (2) when penetrating through the hot pressing roll (5), and the hot pressing roll (5) hot presses the protective film (4) to thermally compound the diaphragm (2) and the monolithic negative electrode sheet (A1); the protective film (4) passes through the hot pressing roller (5), is tensioned by the tensioning roller (7), is wound on the material receiving roller (8), and is wound and recovered by the material receiving roller (8).

7. The process for thermally compounding and manufacturing the battery cell according to claim 6, wherein: the diaphragm (2) and the single-sheet negative electrode sheet (A1) are subjected to surface thermal compounding between the hot pressing rollers (5) and penetrate between the two symmetrically arranged bonding rollers (6), and the bonding rollers (6) are used for thermally compounding and bonding the diaphragm (2) on two sides extending to the outer edge part of the single-sheet negative electrode sheet (A1) into a whole to form a continuous electrode sheet bag.

8. The process of claim 7, wherein the cell is manufactured by thermal compounding, and the process comprises the following steps: the continuous pole piece bags are conveyed to the cutting mechanism (9) forwards, and the cutting mechanism (9) cuts the continuous pole piece bags at the position of the middle line of the gap between two adjacent single-sheet negative pole pieces (A1) one by one to form a cathode pole piece bag (A2).

9. The process of claim 8, wherein the cell is manufactured by thermal compounding, and the process comprises the following steps: the positive plate and the cathode plate bag are overlapped in the step S4, and the process in the step S4 sequentially comprises CCD alignment lamination, full-overlapping mechanical arm blanking, jig transfer transmission, battery encapsulation, OMM size detection, short circuit/thickness/weight detection and good product/NG battery blanking.

10. The process of claim 9, wherein the cell is manufactured by thermal compounding, and the process comprises the following steps: in the step S4, the positive plate (B) and the negative plate bag (a 2) are aligned by the CCD (10), and then are stacked in a staggered manner to form a cell, wherein the upper layer and the lower layer of the cell are the negative plate bags (a 2).

Technical Field

The invention relates to the field of lithium ion batteries, in particular to a thermal compounding and manufacturing process of a battery core in the field of lithium ion power batteries.

Background

With the development of new energy greatly promoted by the state, the demand of various industries on lithium ion power batteries is increasing day by day, and a battery cell in a composition structure of the lithium ion power battery is a core component of the lithium ion power battery, and the battery cell is generally formed by mutually overlapping positive and negative pole pieces in a staggered manner. The battery core composition structure comprises a plurality of positive and negative pole pieces which are staggered and overlapped up and down, and the positive and negative pole pieces are isolated and insulated by a diaphragm.

The existing battery core manufacturing process comprises two modes of strip lamination and single lamination according to different diaphragm inserting processes, namely continuous diaphragms and single diaphragm lamination are adopted during lamination. The belt-shaped lamination process is more widely applied in domestic markets due to higher productivity, and the single lamination process is less applied due to the fact that the productivity cannot meet the actual production requirement. For the strip lamination process, positive and negative pole pieces are alternately placed on a lamination platform during lamination, a strip diaphragm is circularly pulled back and forth above the lamination platform, the positive pole piece or the negative pole piece is covered on the surface of the positive pole piece or the negative pole piece after being laminated, and then the diaphragm is cut; this kind of lamination mode, belt form diaphragm tensioning and by the round trip pulling in the lamination process, there is stress inside, and the diaphragm surface can appear wrinkling the circumstances such as after deciding, influences electric core quality. For the single-sheet lamination process, the diaphragm is firstly cut into a single-sheet structure before lamination, the single-sheet diaphragm is laminated on the surface of the positive plate or the negative plate after the positive plate and the negative plate are laminated, the lamination process needs to take the diaphragm for multiple times to laminate the diaphragm, so that the lamination efficiency is low, the diaphragm needs to be aligned before lamination for ensuring the position precision of the lamination at each time, and the position precision of the lamination is difficult to effectively ensure.

The lithium battery devices with more advanced technology at home are mainly mastered by foreign device suppliers, and compared with the ribbon stacking process and the single-sheet stacking process, the lithium battery devices with more advanced technology at present are the lamination devices of the korean LG company, the device adopts a manufacturing process to synchronously and linearly drive the negative plate and the positive plate forwards to form two linear conveying paths which are parallel and spaced up and down, simultaneously, two coiled strip-shaped diaphragms are correspondingly arranged below the negative pole piece conveying path and between the positive pole conveying path and the negative pole conveying path, and the strip diaphragm is horizontally pulled out, and passes through the hot-pressing rollers arranged at intervals up and down together with the positive and negative pole pieces for hot compounding, cutting the strip diaphragm along the gap between two adjacent pole pieces in the horizontal direction to form a unit body which is sequentially provided with the diaphragm, a negative pole piece, the diaphragm and a positive pole piece from top to bottom, and then sequentially laminating the unit body after the unit body is aligned by a CCD (charge coupled device) to form a battery cell; according to the manufacturing process, the middle unit body is added, the diaphragm is bonded on the surfaces of the positive and negative pole pieces in a thermal compounding mode before being cut, the problem of internal stress existing in direct lamination of the strip diaphragm is solved to a certain extent, and meanwhile, the CCD aligning part improves the aligning precision when the unit bodies are laminated. However, in the unit body manufacturing process, the unit body is manufactured in a blind stacking mode, that is, the positive and negative electrode plates are synchronously and linearly conveyed and stacked, the alignment between the vertically arranged positive and negative electrode plates is lacked, and the accuracy of the positive and negative electrode plates in the unit body cannot be ensured. In addition, the side parts of the positive and negative pole pieces of the laminated battery core manufactured by the manufacturing process are all in an open structure, and the electrolyte is filled around the outside of the laminated battery core, so that the outer edges of the positive pole piece and the negative pole piece in the open structure are in contact with the electrolyte around the outside, and the short circuit and flammability potential safety hazard exists in the actual use process. Aiming at the domestic lithium battery industry and the technical current situation, a brand-new battery core manufacturing process and a manufacturing production line thereof are designed.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a pole piece bag which is manufactured by sealing and coating an upper layer and a lower layer of diaphragms on a single pole piece, and a battery core is formed by aligning and laminating the pole piece and the pole piece bag, thereby solving the diaphragm wrinkling problem, ensuring the position precision between the positive pole piece and the negative pole piece, simplifying the single diaphragm aligning procedure of the traditional lamination by adopting the diaphragms with the size larger than that of the pole piece in the bag manufacturing process, effectively improving the lamination efficiency, and reducing the short circuit and flammability condition and improving the battery core thermal compounding manufacturing process by utilizing the diaphragm bag to block the direct contact of the pole piece in the diaphragm fully-coated single pole piece after the electrolyte is filled.

The technical scheme adopted by the invention is as follows: a process for manufacturing a battery cell by thermal compounding comprises the following process steps:

s1, manufacturing a first pole piece: forming a first pole piece belt of a belt-shaped structure through a pole lug, and cutting the pole piece to form a single-piece first pole piece;

s2, preparing a second pole piece: forming a second pole piece belt of a belt-shaped structure with the polarity opposite to that of the first pole piece in the step S1 through a pole lug, and cutting the pole piece to form a second pole piece in a single sheet shape;

s3, pole piece bag making: in the process of linear transmission of the first or second single-sheet pole piece in the step S1 or S2, the front and back sides of the first or second pole piece are synchronously covered with strip-shaped diaphragms, the diaphragms on the two sides are respectively bonded with the front and back side walls of the first or second pole piece in a thermal compounding manner, the diaphragms on the front and back sides extend to the outer side of the first or second pole piece and are bonded with each other to form a continuous pole piece bag wrapping the first or second pole piece, and the continuous pole piece bag is cut into single pole piece bags;

s4, preparing a battery cell: when the first pole piece is used for making the bag in the step S3, the second pole piece in the step S2 and the single pole piece bag in the step S3 are overlapped in a staggered mode to form a battery cell; when the second pole piece is used for making the pouch in step S3, the first pole piece in step S1 and the single pole piece pouch in step S3 are overlapped in an interlaced manner to form a battery cell.

Preferably, the first pole piece in the step S1 is a positive pole piece, and the process in the step S1 sequentially includes unwinding and deviation rectifying of the positive pole piece, tension buffering, process deviation rectifying, die forming of a tab, CCD detection of tab size, die cutting of a die into pieces, CCD detection of the tab, anode piece blanking and anode piece buffering.

Preferably, the second pole piece in the step S2 is a negative pole piece, and the process in the step S2 sequentially includes negative pole piece unwinding correction, tension buffer storage, process correction, laser forming of a tab, CCD detection of tab size, laser cutting of a piece, pole piece dust removal, and CCD detection of pole piece size.

Preferably, the pole piece bag making in the step S3 is a negative pole piece, and the process in the step S3 sequentially includes pole piece and diaphragm compounding, pole piece and diaphragm protection film entering, pole piece preheating, pole piece hot pressing, pole piece short circuit testing, CCD diaphragm size detection, die diaphragm cutting, cathode pole piece bag blanking and cathode pole piece bag caching.

Preferably, in step S3, two sides of the monolithic negative electrode sheet linearly and horizontally conveyed forward are respectively provided with a separator roll, and the separator on the separator roll is respectively pulled out along the conveying direction of the monolithic negative electrode sheet and passes through the hot press rolls symmetrically arranged on two sides of the monolithic negative electrode sheet.

Preferably, the two sides of the monolithic negative electrode plate are respectively provided with a protective film material roll, a tensioning roll and a material receiving roll, and a protective film pulled out by the protective film material roll covers the surface of the diaphragm when passing through the hot-pressing roll, so that the diaphragm is protected when the hot-pressing roll hot-presses the composite diaphragm on the monolithic negative electrode plate; the protective film passes through the hot pressing roller, is tensioned by the tensioning roller, is wound on the material receiving roller, and is wound and recovered by the material receiving roller.

Preferably, the diaphragm and the single-sheet negative electrode sheet pass through two symmetrically arranged bonding rollers after surface thermal compounding is completed between the hot pressing rollers, and the bonding rollers thermally compound and bond the diaphragms extending to the outer edge part of the single-sheet negative electrode sheet into a whole to form a continuous electrode sheet bag.

Preferably, the continuous electrode piece bags are conveyed forwards to the cutting mechanism, and the cutting mechanism is used for sequentially cutting the diaphragm at the position of the central line between the two adjacent monolithic negative electrode pieces to form the cathode electrode piece bag.

Preferably, the positive plate and the cathode plate bag are overlapped in the step S4, and the process in the step S4 sequentially comprises CCD alignment lamination, full-overlapping manipulator blanking, jig transfer transmission, battery encapsulation, OMM size detection, short circuit/thickness/weight detection and good product/NG battery blanking.

Preferably, in step S4, the positive electrode plates and the negative electrode plate bags are aligned by the CCD, and then are stacked in a staggered manner to form the battery cell, wherein the two outer layers of the battery cell are the negative electrode plate bags, respectively.

The invention has the beneficial effects that:

the invention designs a pole piece bag which is manufactured by sealing and coating a single pole piece by an upper layer of diaphragm and a lower layer of diaphragm, and forms a battery cell by aligning and superposing the pole piece and the pole piece bag, thereby solving the problem of diaphragm wrinkling, ensuring the position precision between the positive pole piece and the negative pole piece, simplifying the single diaphragm aligning procedure of the traditional lamination by adopting the diaphragm larger than the size of the pole piece in the bag manufacturing process, effectively improving the lamination efficiency, reducing the short circuit and flammability condition and improving the battery cell thermal compounding manufacturing process with safety coefficient by using the diaphragm bag to block the pole piece in the structure of the diaphragm fully coated single pole piece after the electrolyte is filled.

The invention belongs to a single-sheet stacking process, which integrally comprises a single-sheet manufacturing process, a pole-piece bag-making process and a battery core manufacturing process, wherein the single-sheet manufacturing process is used for cutting a pole piece of a strip-shaped pole piece bag into a single positive plate and a single negative plate after pole pieces are cut, the pole piece bag-making process is used for carrying out surface thermal compounding and edge thermal compounding on the pole piece with one attribute by using a double-layer diaphragm to form a single-attribute pole piece bag fully coated by the diaphragm, and the single-attribute pole piece bag and the single-sheet with the other attribute are aligned by a CCD (charge coupled device) and then are stacked to manufacture a battery core.

The invention replaces the open type unit body structure of the diaphragm, the negative plate, the diaphragm and the positive plate from top to bottom in sequence by creatively introducing the pole piece bag manufacturing process, thereby realizing the lamination of the single diaphragm; the problem that the quality of a battery core is influenced by wrinkling of the surface of the laminated diaphragm caused by the stress problem in the traditional strip diaphragm laminating process is solved; meanwhile, compared with the traditional single diaphragm and single positive and negative pole piece process, the number of times of lamination of a single battery cell of the lamination section is reduced by more than one time, and the lamination efficiency is effectively improved. Meanwhile, compared with the problem that the positive plate and the negative plate are blindly stacked in the unit structure manufacturing process, the position accuracy of the positive plate and the negative plate in the unit cannot be accurately ensured, the pole piece bag structure only has a pole piece with one polarity, and the pole pieces with two polarities are not needed to be aligned in the pole piece bag manufacturing process, so that the position accuracy of the pole pieces is effectively ensured; meanwhile, the upper and lower layers of diaphragms extending outwards to the outer edge part of the pole piece are subjected to hot-pressing adhesion at the outer edge part to form a sealed bag body, and in the subsequent manufacturing of the battery cell, compared with the traditional technology for sealing the pole piece with one attribute, the pole piece bag disclosed by the invention has the advantages that the pole piece with one attribute is isolated, only one attribute pole piece of the battery cell is directly contacted with the electrolyte, so that the short circuit spontaneous combustion problem caused by two-stage conduction in the use process of the battery cell can be effectively reduced, and the safety performance of the battery cell is improved. In addition, in the pole piece bag making process, the upper and lower two layers of diaphragms need to be bonded from the outer edge to the outer side of the pole piece, so that the size of the diaphragm is larger than that of the pole piece in the diaphragm, the requirement on the diaphragm position accuracy is relatively low, an independent procedure is not needed for accurate diaphragm alignment, the traditional battery core making process is effectively simplified, and the battery core making efficiency is improved.

Specifically, the method comprises the following steps: compared with the manufacture of the battery cell of the Korean LG company, the pole piece bag with the structure replaces the unit bodies of the LG company which are the diaphragm, the negative pole piece, the diaphragm and the positive pole piece from top to bottom, and in the process of manufacturing the pole piece bag, the alignment of the positive pole piece and the negative pole piece is not needed because only the pole piece bag with one attribute is involved; meanwhile, in the bag making process, the size of the diaphragm is larger than that of the pole piece, so that the diaphragm can extend to the outer edge of the pole piece in the horizontal plane and the upper diaphragm and the lower diaphragm are adhered to each other at the outer edge part, the requirement on the diaphragm alignment precision is lower, and a special diaphragm alignment procedure is not needed; therefore, in the integral manufacturing process of the battery cell, the CCD is aligned only when the pole piece and the pole piece bag are overlapped, and the lamination precision is effectively ensured.

Meanwhile, the pole piece bags are manufactured into a three-layer structure at one time, and compared with the traditional battery core manufacturing process, the battery core manufacturing method has the working procedures of diaphragm stacking, negative pole piece stacking, diaphragm stacking, positive pole piece stacking and four-time lamination; the invention can be completed by only two lamination processes of laminating the positive plate bag and laminating the positive plate, the efficiency of the lamination manufacturing section is doubled, and the accumulated position error of multiple laminations can be reduced.

In addition, the pole piece belt manufacturing process is originally created, full coating of the diaphragm of the counter pole piece layer is achieved, compared with a traditional pole piece side part open type battery core, the battery core with one polarity in the battery core is completely coated by the diaphragm, after electrolyte is filled, the pole piece with only one polarity is directly communicated with electrolyte outside the battery core, the structure plays a role in protecting and blocking the pole pieces in the pole piece belt, short circuit and spontaneous combustion conditions caused by conduction of the pole pieces with different polarities in the battery core can be effectively avoided in the use process of the battery, and the safety coefficient of the use of the battery is improved.

In addition, the negative plate is preferably used as the manufactured pole piece in the pole piece bag aiming at the condition that the size of the current negative plate is larger than that of the current positive plate, and the reason is that when the upper and lower layers of diaphragms are hot rolled from the upper and lower sides of the edge of the pole piece to the middle of the pole piece along the outline of the pole piece in the bag manufacturing process, the diaphragms are punctured by external reaction force generated by rolling the corners of the pole piece, so that the pole piece is exposed outside. The battery core internal state of finally making in the coincide process about pole piece and pole piece bag still passes through the diaphragm separation between the positive and negative pole pieces, and because the negative pole piece size is greater than the positive plate, the negative pole piece outer edge can extend to the positive plate outside, is like this at the edge of negative pole piece by the diaphragm cladding, has the interval with the positive plate side after the lamination, and the corner position of negative pole piece can not contact with the positive plate, avoids the short circuit condition because of positive and negative pole piece contact leads to.

Drawings

FIG. 1 is a schematic diagram of the process steps of the present invention.

FIG. 2 is a schematic process flow diagram of FIG. 1.

Fig. 3 is a schematic flow chart of a bag making process in example 1 of the present invention.

Fig. 4 is a schematic flow chart of a bag making process in example 2 of the present invention.

Fig. 5 is a schematic diagram illustrating lamination of a pole piece and a pole piece pocket in a battery cell manufactured according to the present invention.

Fig. 6 is a second schematic diagram illustrating the lamination of a pole piece and a pole piece bag in a battery cell manufactured by the invention.

Fig. 7 is a cross-sectional view of a cell formed according to the present invention.

Fig. 8 is a schematic diagram of a pole piece pocket of a battery cell manufactured according to the present invention.

Fig. 9 is a schematic diagram illustrating lamination of a pole piece and a pole piece pocket in another cell manufactured according to the present invention.

Fig. 10 is a second schematic diagram illustrating lamination of a pole piece and a pole piece pocket in another cell manufactured according to the present invention.

Fig. 11 is a cross-sectional view of another cell formed according to the present invention.

Fig. 12 is a schematic diagram of a pole piece pouch of another cell made according to the present invention.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

example 1: as shown in fig. 1 to 3, the technical solution adopted in embodiment 1 of the present invention is as follows: a process for manufacturing a battery cell by thermal compounding comprises the following process steps:

s1, manufacturing a first pole piece: forming a first pole piece belt of a belt-shaped structure through a pole lug, and cutting the pole piece to form a single-piece first pole piece;

s2, preparing a second pole piece: forming a second pole piece belt of a belt-shaped structure with the polarity opposite to that of the first pole piece in the step S1 through a pole lug, and cutting the pole piece to form a second pole piece in a single sheet shape;

s3, pole piece bag making: in the process of linear transmission of the first or second single-sheet pole piece in the step S1 or S2, the front and back sides of the first or second pole piece are synchronously covered with strip-shaped diaphragms, the diaphragms on the two sides are respectively bonded with the front and back side walls of the first or second pole piece in a thermal compounding manner, the diaphragms on the front and back sides extend to the outer side of the first or second pole piece and are bonded with each other to form a continuous pole piece bag wrapping the first or second pole piece, and the continuous pole piece bag is cut into single pole piece bags;

s4, preparing a battery cell: when the first pole piece is used for making the bag in the step S3, the second pole piece in the step S2 and the single pole piece bag in the step S3 are overlapped in a staggered mode to form a battery cell; when the second pole piece is used for making the pouch in step S3, the first pole piece in step S1 and the single pole piece pouch in step S3 are overlapped in an interlaced manner to form a battery cell.

The first pole piece in the step S1 is a positive pole piece, and the process in the step S1 sequentially includes positive pole piece unwinding correction, tension caching, process correction, die forming of a tab, CCD detection of tab size, die cutting of a die into pieces, CCD detection of a pole piece, anode piece blanking and anode piece caching.

The second pole piece in the step S2 is a negative pole piece, and the process in the step S2 sequentially includes negative pole piece unwinding correction, tension buffer, process correction, laser forming of a pole tab, CCD detection of the size of the pole tab, laser cutting of the pole tab into pieces, pole piece dust removal, and CCD detection of the size of the pole piece.

The pole piece bag making in the step S3 is a negative pole piece, and the process in the step S3 sequentially comprises the steps of pole piece and diaphragm compounding, pole piece and diaphragm protection film entering, pole piece preheating, pole piece hot pressing, pole piece short circuit testing, diaphragm size detection by a CCD (charge coupled device), diaphragm cutting by a die, cathode pole piece bag blanking and cathode pole piece bag caching.

In step S3, separator material rolls 1 are respectively disposed on both sides of the monolithic negative electrode sheet a1 that is conveyed forward in a straight line and horizontally, and separators 2 on the separator material rolls 1 are respectively pulled out in the conveying direction of the monolithic negative electrode sheet a1 and pass through hot press rolls 5 symmetrically disposed on both sides of the monolithic negative electrode sheet a 1.

The two sides of the single-sheet negative electrode sheet A1 are respectively provided with a protective film coil 3, a tensioning roller 7 and a material receiving roller 8, and a protective film 4 pulled out by the protective film coil 3 covers the surface of the diaphragm 2 when passing through the hot-pressing roller 5, so that the diaphragm 2 is protected when the hot-pressing roller 5 hot-presses the composite diaphragm 2 on the single-sheet negative electrode sheet A1; the protective film 4 penetrates through the hot pressing roller 5, is tensioned by the tensioning roller 7, is wound on the material receiving roller 8, and is wound and recovered by the material receiving roller 8.

The diaphragm 2 and the single-sheet negative electrode sheet A1 pass through two symmetrically arranged bonding rollers 6 after surface thermal compounding is completed between the hot pressing rollers 5, and the bonding rollers 6 thermally compound and bond the diaphragm 2 at two sides extending to the outer edge part of the single-sheet negative electrode sheet A1 into a whole to form a continuous electrode sheet bag.

The continuous pole piece bags are conveyed forwards to the cutting mechanism 9, the cutting mechanism 9 sequentially cuts the diaphragm 2 at the middle line position of the gap between two adjacent single-sheet negative pole pieces A1 to form a cathode pole piece bag A2.

The positive plate and the cathode plate bag are overlapped in the step S4, and the process in the step S4 sequentially comprises CCD alignment lamination, full-overlapping mechanical arm blanking, jig transfer transmission, battery encapsulation, OMM size detection, short circuit/thickness/weight detection and good product/NG battery blanking.

In step S4, the positive plate B and the negative plate bag a2 are aligned by the CCD10, and then are stacked in a staggered manner to form a battery cell, wherein the two outer layers of the battery cell are the negative plate bags a 2.

Furthermore, the invention designs a pole piece bag which is manufactured by sealing and coating a single pole piece by an upper layer of diaphragm and a lower layer of diaphragm, and forms a battery core by aligning and superposing the pole piece and the pole piece bag, thereby solving the problem of diaphragm wrinkling, ensuring the position precision between the positive pole piece and the negative pole piece, simplifying the single diaphragm aligning procedure of the traditional lamination by adopting the diaphragm with the size larger than the size of the pole piece in the bag manufacturing process, effectively improving the lamination efficiency, and the structure of the diaphragm fully coating the single pole piece utilizes the diaphragm bag to block the pole piece in the diaphragm from directly contacting with the electrolyte after the electrolyte is filled, reducing the short circuit and flammability conditions, and improving the battery safety coefficient and the battery core thermal compounding manufacturing process.

The invention belongs to a single-sheet stacking process, which integrally comprises a single-sheet manufacturing process, a pole-piece bag-making process and a battery core manufacturing process, wherein the single-sheet manufacturing process is used for cutting a pole piece of a strip-shaped pole piece bag into a single positive plate and a single negative plate after pole pieces are cut, the pole piece bag-making process is used for carrying out surface thermal compounding and edge thermal compounding on the pole piece with one attribute by using a double-layer diaphragm to form a single-attribute pole piece bag fully coated by the diaphragm, and the single-attribute pole piece bag and the single-sheet with the other attribute are aligned by a CCD (charge coupled device) and then are stacked to manufacture a battery core.

The invention replaces the open type unit body structure of the diaphragm, the negative plate, the diaphragm and the positive plate from top to bottom in sequence by creatively introducing the pole piece bag manufacturing process, thereby realizing the lamination of the single diaphragm; the problem that the quality of a battery core is influenced by wrinkling of the surface of the laminated diaphragm caused by the stress problem in the traditional strip diaphragm laminating process is solved; meanwhile, compared with the traditional single diaphragm and single positive and negative pole piece process, the number of times of lamination of a single battery cell of the lamination section is reduced by more than one time, and the lamination efficiency is effectively improved. Meanwhile, compared with the problem that the positive plate and the negative plate are blindly stacked in the unit structure manufacturing process, the position accuracy of the positive plate and the negative plate in the unit cannot be accurately ensured, the pole piece bag structure only has a pole piece with one polarity, and the pole pieces with two polarities are not needed to be aligned in the pole piece bag manufacturing process, so that the position accuracy of the pole pieces is effectively ensured; meanwhile, the upper and lower layers of diaphragms extending outwards to the outer edge part of the pole piece are subjected to hot-pressing adhesion at the outer edge part to form a sealed bag body, and in the subsequent manufacturing of the battery cell, compared with the traditional technology for sealing the pole piece with one attribute, the pole piece bag disclosed by the invention has the advantages that the pole piece with one attribute is isolated, only one attribute pole piece of the battery cell is directly contacted with the electrolyte, so that the short circuit spontaneous combustion problem caused by two-stage conduction in the use process of the battery cell can be effectively reduced, and the safety performance of the battery cell is improved. In addition, in the pole piece bag making process, the upper and lower two layers of diaphragms need to be bonded from the outer edge to the outer side of the pole piece, so that the size of the diaphragm is larger than that of the pole piece in the diaphragm, the requirement on the diaphragm position accuracy is relatively low, an independent procedure is not needed for accurate diaphragm alignment, the traditional battery core making process is effectively simplified, and the battery core making efficiency is improved.

Specifically, the method comprises the following steps: compared with the manufacture of the battery cell of the Korean LG company, the pole piece bag with the structure replaces the unit bodies of the LG company which are the diaphragm, the negative pole piece, the diaphragm and the positive pole piece from top to bottom, and in the process of manufacturing the pole piece bag, the alignment of the positive pole piece and the negative pole piece is not needed because only the pole piece bag with one attribute is involved; meanwhile, in the bag making process, the size of the diaphragm is larger than that of the pole piece, so that the diaphragm can extend to the outer edge of the pole piece in the horizontal plane and the upper diaphragm and the lower diaphragm are adhered to each other at the outer edge part, the requirement on the diaphragm alignment precision is lower, and a special diaphragm alignment procedure is not needed; therefore, in the integral manufacturing process of the battery cell, the CCD is aligned only when the pole piece and the pole piece bag are overlapped, and the lamination precision is effectively ensured.

Meanwhile, the pole piece bags are manufactured into a three-layer structure at one time, and compared with the traditional battery core manufacturing process, the battery core manufacturing method has the working procedures of diaphragm stacking, negative pole piece stacking, diaphragm stacking, positive pole piece stacking and four-time lamination; the invention can be completed by only two lamination processes of laminating the positive plate bag and laminating the positive plate, the efficiency of the lamination manufacturing section is doubled, and the accumulated position error of multiple laminations can be reduced.

In addition, the pole piece belt manufacturing process is originally created, full coating of the diaphragm of the counter pole piece layer is achieved, compared with a traditional pole piece side part open type battery core, the battery core with one polarity in the battery core is completely coated by the diaphragm, after electrolyte is filled, the pole piece with only one polarity is directly communicated with electrolyte outside the battery core, the structure plays a role in protecting and blocking the pole pieces in the pole piece belt, short circuit and spontaneous combustion conditions caused by conduction of the pole pieces with different polarities in the battery core can be effectively avoided in the use process of the battery, and the safety coefficient of the use of the battery is improved.

In addition, the negative plate is preferably used as the manufactured pole piece in the pole piece bag aiming at the condition that the size of the current negative plate is larger than that of the current positive plate, and the reason is that when the upper and lower layers of diaphragms are hot rolled from the upper and lower sides of the edge of the pole piece to the middle of the pole piece along the outline of the pole piece in the bag manufacturing process, the diaphragms are punctured by external reaction force generated by rolling the corners of the pole piece, so that the pole piece is exposed outside. The battery core internal state of finally making in the coincide process about pole piece and pole piece bag still passes through the diaphragm separation between the positive and negative pole pieces, and because the negative pole piece size is greater than the positive plate, the negative pole piece outer edge can extend to the positive plate outside, is like this at the edge of negative pole piece by the diaphragm cladding, has the interval with the positive plate side after the lamination, and the corner position of negative pole piece can not contact with the positive plate, avoids the short circuit condition because of positive and negative pole piece contact leads to.

The invention replaces the open type unit body structure of the diaphragm, the negative plate, the diaphragm and the positive plate from top to bottom in sequence by creatively introducing the pole piece bag manufacturing process, thereby realizing the lamination of the single diaphragm; the problem that the quality of a battery core is influenced by wrinkling of the surface of the laminated diaphragm caused by the stress problem in the traditional strip diaphragm laminating process is solved; meanwhile, compared with the traditional single diaphragm and single positive and negative pole piece process, the number of times of lamination of a single battery cell of the lamination section is reduced by more than one time, and the lamination efficiency is effectively improved. Meanwhile, compared with the problem that the positive plate and the negative plate are blindly stacked in the unit structure manufacturing process, the position accuracy of the positive plate and the negative plate in the unit cannot be accurately ensured, the pole piece bag structure only has a pole piece with one polarity, and the pole pieces with two polarities are not needed to be aligned in the pole piece bag manufacturing process, so that the position accuracy of the pole pieces is effectively ensured; meanwhile, the upper and lower layers of diaphragms extending outwards to the outer edge part of the pole piece are subjected to hot-pressing adhesion at the outer edge part to form a sealed bag body, and in the subsequent manufacturing of the battery cell, compared with the traditional technology for sealing the pole piece with one attribute, the pole piece bag disclosed by the invention has the advantages that the pole piece with one attribute is isolated, only one attribute pole piece of the battery cell is directly contacted with the electrolyte, so that the short circuit spontaneous combustion problem caused by two-stage conduction in the use process of the battery cell can be effectively reduced, and the safety performance of the battery cell is improved. In addition, in the pole piece bag making process, the upper and lower two layers of diaphragms need to be bonded from the outer edge to the outer side of the pole piece, so that the size of the diaphragm is larger than that of the pole piece in the diaphragm, the requirement on the diaphragm position accuracy is relatively low, an independent procedure is not needed for accurate diaphragm alignment, the traditional battery core making process is effectively simplified, and the battery core making efficiency is improved.

Specifically, the method comprises the following steps: compared with the manufacture of the battery cell of the Korean LG company, the pole piece bag with the structure replaces the unit bodies of the LG company which are the diaphragm, the negative pole piece, the diaphragm and the positive pole piece from top to bottom, and in the process of manufacturing the pole piece bag, the alignment of the positive pole piece and the negative pole piece is not needed because only the pole piece bag with one attribute is involved; meanwhile, in the bag making process, the size of the diaphragm is larger than that of the pole piece, so that the diaphragm can extend to the outer edge of the pole piece in the horizontal plane and the upper diaphragm and the lower diaphragm are adhered to each other at the outer edge part, the requirement on the diaphragm alignment precision is lower, and a special diaphragm alignment procedure is not needed; therefore, in the integral manufacturing process of the battery cell, the CCD is aligned only when the pole piece and the pole piece bag are overlapped, and the lamination precision is effectively ensured.

Meanwhile, the pole piece bags are manufactured into a three-layer structure at one time, and compared with the traditional battery core manufacturing process, the battery core manufacturing method has the working procedures of diaphragm stacking, negative pole piece stacking, diaphragm stacking, positive pole piece stacking and four-time lamination; the invention can be completed by only two lamination processes of laminating the positive plate bag and laminating the positive plate, the efficiency of the lamination manufacturing section is doubled, and the accumulated position error of multiple laminations can be reduced.

In addition, the pole piece belt manufacturing process is originally created, full coating of the diaphragm of the counter pole piece layer is achieved, compared with a traditional pole piece side part open type battery core, the battery core with one polarity in the battery core is completely coated by the diaphragm, after electrolyte is filled, the pole piece with only one polarity is directly communicated with electrolyte outside the battery core, the structure plays a role in protecting and blocking the pole pieces in the pole piece belt, short circuit and spontaneous combustion conditions caused by conduction of the pole pieces with different polarities in the battery core can be effectively avoided in the use process of the battery, and the safety coefficient of the use of the battery is improved.

In addition, the negative plate is preferably used as the manufactured pole piece in the pole piece bag aiming at the condition that the size of the current negative plate is larger than that of the current positive plate, and the reason is that when the upper and lower layers of diaphragms are hot rolled from the upper and lower sides of the edge of the pole piece to the middle of the pole piece along the outline of the pole piece in the bag manufacturing process, the diaphragms are punctured by external reaction force generated by rolling the corners of the pole piece, so that the pole piece is exposed outside. The battery core internal state of finally making in the coincide process about pole piece and pole piece bag still passes through the diaphragm separation between the positive and negative pole pieces, and because the negative pole piece size is greater than the positive plate, the negative pole piece outer edge can extend to the positive plate outside, is like this at the edge of negative pole piece by the diaphragm cladding, has the interval with the positive plate side after the lamination, and the corner position of negative pole piece can not contact with the positive plate, avoids the short circuit condition because of positive and negative pole piece contact leads to.

Example 2: as shown in fig. 4, a schematic diagram of a bag making process flow in embodiment 2 of the present invention is shown, and the production line in this embodiment has the same components as the production line in embodiment 1, and the difference is that the production line in this embodiment exchanges the order of the edge thermal compounding bag making process and the bag making process, that is, after the surface thermal compounding process is completed, the diaphragms are cut along the middle of the space between two adjacent pole pieces, and after the cutting is completed, the diaphragms on the upper and lower sides of the outer edge of the pole piece are subjected to edge thermal compounding along the outer contour of the pole piece by the bonding roller 6 to form a bag. The process comprises the steps of embodiment 1, cutting continuous diaphragms after edge thermal compounding, and due to the fact that stress exists in the continuous diaphragms after tensioning, the situation that the upper and lower diaphragms are bonded and then separated after variable-pressure thermal compounding due to the internal stress of the continuous diaphragms possibly occurs after the edge thermal compounding. However, because the diaphragm is made of flexible materials, the edges of the cut upper and lower layers of diaphragms are in a suspended state, and the problem that the thermal compounding quality of the subsequent edges is affected due to the fact that the surfaces of the edges of the diaphragms are bent and the like in the conveying process of conveying the cut diaphragms to the bonding roller 6 also exists.

As shown in fig. 5 to 8, a schematic diagram of a cell structure manufactured by the process of the present invention includes a pole piece bag and a second pole piece b, wherein the pole piece bag includes a first pole piece a1 and a diaphragm a2, the diaphragm a2 includes two pieces, and the two diaphragms a2 respectively horizontally cover the upper and lower surfaces of the first pole piece a1 and are bonded to the surface of the first pole piece a1 by thermal recombination; the diaphragm a2 horizontally extends to the outer edge of the first pole piece a1, the outer edge parts a3 of the diaphragms a2 on the upper and lower sides are bent towards the middle part along the outer contour of the first pole piece a1 and are thermally compounded and bonded together to form a closed pole piece bag which covers the first pole piece a 1; and after the electrode piece bag and the second electrode piece b are aligned by the CCD, the electrode piece bag and the second electrode piece b are overlapped in a staggered mode to form the battery cell. The membrane a2 is bonded by hot-rolling on the surface of the first pole piece a1 by a hot-rolling roller. The outer edge parts a3 of the two diaphragms a2 are bent around the surface of the first pole piece a1 by a hot pressing roller and pressed to the middle part of the first pole piece a1 by the hot pressing roller and are integrally bonded with each other. The first pole piece a1 is a negative pole piece, the second pole piece b is a positive pole piece, and the side edge of the first pole piece a1 extends to the outer side of the side edge of the second pole piece b. After the second pole piece b is overlapped with the pole piece bag, the outer side edge of the second pole piece b forms a distance with the outer side edge of the pole piece bag, so that the short circuit caused by the contact of a puncture part formed by the side edge angle of the first pole piece a1 puncturing the diaphragm a2 and the second pole piece b when the outer edge part a3 is bonded by hot rolling is avoided. The second pole piece b and the pole piece bag are overlapped to form a battery core, an electrolyte layer c is filled outside the battery core, the electrolyte layer c is directly contacted with the second pole piece b, and the first pole piece a1 is insulated and isolated from the second pole piece b and the electrolyte layer c through a diaphragm a2 outside the pole piece bag.

As shown in fig. 9 to 12, which are schematic diagrams of another cell structure manufactured by the process of the present invention, the pole piece in the pole piece bag of the cell is replaced by the positive pole piece, and the structure of the pole piece bag is still the same as that of the cell in fig. 4, i.e., the pole piece bag sequentially comprises a diaphragm layer, a pole piece layer and a diaphragm layer from bottom to top, only the pole piece attribute of the pole piece layer is replaced by the positive pole piece, and correspondingly, the single pole piece in lamination is the negative pole piece. Because the sizes of the positive and negative pole pieces are different, the side corners of the pole piece bag are overlapped and then are attached to the surface of the negative pole piece when the pole piece bag and the pole piece bag are aligned and laminated by the CCD and are in direct contact with the negative pole piece, so that the positive pole piece and the negative pole piece can be in direct contact if a diaphragm at the corner position of the pole piece bag is punctured in the process of manufacturing the pole piece bag, and short circuit is caused. When the negative pole piece is adopted as the pole piece layer of the pole piece bag in the battery core in fig. 4, the edge corner of the pole piece bag after lamination is in a suspended state, that is, the edge corner is not in contact with the surface of the positive pole piece. This cell is slightly less secure in terms of the safety factor with which it is made, compared to the cell in fig. 5.

The embodiments of the present invention are merely illustrative of specific embodiments thereof, and are not intended to limit the scope thereof. Since the present invention can be modified by a person skilled in the art, the present invention is not limited to the embodiments described above.