CN107946626B - Pole piece unit and manufacturing method thereof, battery core and manufacturing method thereof, and battery - Google Patents

Abstract

The present invention relates to a pole piece unit and a manufacturing method thereof, a battery cell and a manufacturing method thereof, and a battery. The battery cell manufacturing method is to place a first pole piece between two layers of isolation membranes and fix it with the two layers of isolation membranes to form a pole piece group; cut the pole piece group into a plurality of pole piece units; cut a second pole piece with a polarity opposite to that of the first pole piece into a plurality of second pole piece monomers; and cross-stack the pole piece units and the second pole piece monomers. This method adopts a method of fixing first and then cutting, which is not only convenient for cutting, and the cut surfaces of the two layers of isolation membranes are flat, but also only needs to align the first pole piece and the isolation membrane once during the entire pole piece unit manufacturing process, without the need to align each cut first pole piece and isolation membrane again, which reduces the manufacturing process and further improves the production efficiency.

Description

Pole unit and manufacturing method thereof, battery cell and manufacturing method thereof, battery

Technical Field

The invention relates to a pole piece unit and a manufacturing method thereof, a battery core and a manufacturing method thereof, and a battery.

Background Art

Lithium-ion batteries are widely used due to their high energy density, good environmental performance, high reliability and good processability. Existing lithium-ion battery cells are generally laminated and wound. The structure of laminated cells generally includes positive and negative electrodes stacked at intervals, and the positive and negative electrodes are separated by a separator folded in a Z shape. In the actual production process, the cells with this arrangement not only have low production efficiency and poor precision control, but also the electrodes are easily misaligned, causing short circuits, resulting in poor safety performance of the battery using the cells.

In response to the above problems, a Chinese patent application with the publication number CN 106159347 A and the name of the composite laminated battery cell and its laminated unit and laminated method discloses a composite laminated battery cell, that is, the pole piece and the isolation membrane are cut into suitable sizes and then combined into a laminated unit, and the battery cell is manufactured by stacking the laminated units. In actual use, the battery cell of this structure is composited with the isolation membrane, and even if the pole piece is misaligned, it will not cause a short circuit, thereby improving the safety of the battery cell. However, in the actual manufacturing process of the battery cell of this structure, because the isolation membrane and the pole piece are cut first and then composited, firstly, the unfixed isolation membrane and pole piece are not easy to cut, and it is easy to be misaligned during cutting. Secondly, the isolation membrane and the pole piece after cutting need to be re-positioned before they can be composited. Not only is the process cumbersome, but also the accuracy between the two after re-positioning cannot be guaranteed.

Summary of the invention

The object of the present invention is to provide a pole piece unit with high production efficiency and high alignment accuracy; the object of the present invention is also to provide a pole piece unit manufacturing method with high production efficiency and high alignment accuracy; the object of the present invention is to provide a battery cell with high production efficiency and high alignment accuracy; the object of the present invention is also to provide a battery cell manufacturing method with high production efficiency and high alignment accuracy; the object of the present invention is also to provide a battery using the above-mentioned battery cell.

To achieve the above-mentioned purpose, the technical solution of a pole piece unit of the present invention is: a pole piece unit, including an upper isolation membrane, a lower isolation membrane and a pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes, and the cut surface of the upper and lower isolation membranes is cut at one time after the two are fixed to the pole piece monomer.

To achieve the above-mentioned purpose, the technical solution 1 of a method for manufacturing a pole piece unit of the present invention is: a method for manufacturing a pole piece unit, wherein a pole piece is arranged between two layers of isolation membranes and the two layers of isolation membranes and the pole piece are fixed to form a pole piece group, and the pole piece group is cut to obtain a pole piece unit. The method of fixing first and then cutting is adopted, which is not only convenient for cutting, but also makes the cut surface of the two layers of isolation membranes smooth. In addition, in the whole process of manufacturing the pole piece unit, it is only necessary to align the first pole piece and the isolation membrane once, and it is not necessary to align each first pole piece and isolation membrane after cutting again, which reduces the manufacturing process and further improves the production efficiency.

Technical Solution 2 of a method for manufacturing a pole piece unit of the present invention is a further improvement on Technical Solution 1: the pole piece and the isolation membrane are fixed by composite.

Technical solution 3 of a method for manufacturing a pole piece unit of the present invention is a further improvement on technical solution 1: the pole piece is cut into a plurality of pole piece monomers and then placed between two isolation films, and the pole piece group is cut from the intervals between adjacent pole piece monomers. In this way, the area of the isolation film after cutting is slightly larger than the area of the pole piece monomer, which can better achieve external insulation of the pole piece monomer.

Technical solution 4 of a method for manufacturing a pole piece unit of the present invention is a further improvement on technical solution 3: the intervals between adjacent pole piece monomers are equal, and the pole piece group is cut from the center line of the intervals between adjacent pole piece monomers, so that the multiple pole piece units obtained by cutting have the same shape and are arranged neatly.

Technical solution 5 of a method for manufacturing a pole piece unit of the present invention is a further improvement on the basis of any one of technical solutions 1-4: more than two pole piece units are obtained by one cutting, thereby further improving production efficiency.

Technical solution 6 of a method for manufacturing a pole piece unit of the present invention is a further improvement on technical solution 5: the number of pole piece units obtained after one cutting is the same as the number of pole piece monomers.

To achieve the above-mentioned purpose, the technical solution of a battery cell of the present invention is: it includes a pole piece unit and a second pole piece monomer cross-stacked with the pole piece unit, the pole piece unit includes an upper isolation membrane, a lower isolation membrane and a first pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes, the cut surface of the upper and lower isolation membranes is cut at one time after the two are fixed to the first pole piece monomer, and the first pole piece monomer and the second pole piece monomer have opposite polarities.

To achieve the above-mentioned purpose, the technical solution 1 of a battery cell manufacturing method of the present invention is: a battery cell manufacturing method, placing a first pole piece between two layers of isolation membranes and fixing it with the two layers of isolation membranes to form a pole piece group; cutting the pole piece group into a plurality of pole piece units; cutting a second pole piece with a polarity opposite to that of the first pole piece into a plurality of second pole piece monomers; cross-stacking the pole piece units and the second pole piece monomers. The method of fixing first and then cutting is not only convenient for cutting, but also only requires one alignment of the first pole piece and the isolation membrane during the entire pole piece unit manufacturing process, without the need to align each cut first pole piece monomer and the isolation membrane again, which reduces the manufacturing process and further improves the production efficiency.

Technical solution 2 of a battery cell manufacturing method of the present invention is a further improvement on technical solution 1: the first pole piece and the isolation membrane are fixed by composite.

Technical solution 3 of a method for manufacturing a battery cell of the present invention is a further improvement on technical solution 1: the first pole piece is cut into a plurality of first pole piece monomers and then placed between two isolation films at intervals, and the pole piece group is cut from the intervals between adjacent first pole piece monomers. In this way, the area of the isolation film after cutting is slightly larger than the area of the first pole piece monomer, which can better achieve insulation between the first pole piece monomer and the second pole piece monomer.

Technical solution 4 of a battery cell manufacturing method of the present invention is a further improvement on technical solution 3: the intervals between adjacent first pole piece monomers are equal, and the pole piece group is cut from the center line of the intervals between adjacent first pole piece monomers, so that the multiple pole piece units obtained by cutting have the same shape and are arranged neatly.

Technical solution 5 of a battery cell manufacturing method of the present invention is a further improvement on the basis of any one of technical solutions 1-4: more than two pole piece units are obtained by one cutting, thereby further improving production efficiency.

Technical solution 6 of a battery cell manufacturing method of the present invention is a further improvement on technical solution 5: the number of pole piece units obtained after one cutting is the same as the number of the first pole piece monomers.

Technical solution 7 of a battery cell manufacturing method of the present invention is a further improvement on the basis of any one of technical solutions 1-4: the area of the second pole piece monomer is greater than the area of the first pole piece monomer, which can improve the energy density of the battery cell.

Technical solution 8 of a battery cell manufacturing method of the present invention is a further improvement on the basis of any one of technical solutions 1-4: the positive and negative electrode ears of the battery cell can be arranged on one side of the battery cell or on both sides of the battery cell respectively.

Technical solution 9 of a battery cell manufacturing method of the present invention is a further improvement on technical solution 1: the first pole piece is adhered to the isolation membrane.

To achieve the above-mentioned purpose, the technical solution of a battery of the present invention is: a battery, including a battery cell, the battery cell including a pole piece unit and a second pole piece monomer cross-stacked with the pole piece unit, the pole piece unit including an upper isolation membrane, a lower isolation membrane and a first pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes as a whole, the cut surface of the upper and lower isolation membranes is cut at one time after the two are fixed to the first pole piece monomer, and the first pole piece monomer and the second pole piece monomer have opposite polarities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a position structure diagram of a pole piece assembly before composite in a specific embodiment 1 of a method for manufacturing a battery cell according to the present invention;

FIG2 is a structural diagram of a composite electrode assembly in a specific embodiment 1 of a method for manufacturing a battery cell according to the present invention;

FIG3 is a top view of a pole piece group being cut in a specific embodiment 1 of a method for manufacturing a battery cell according to the present invention;

FIG4 is a structural diagram of a cell manufacturing method according to a specific embodiment 1 of the present invention after the electrode assembly is cut;

5 is a structural diagram of a cross-stacked pole piece unit and a second pole piece unit in a specific embodiment 1 of a battery cell manufacturing method of the present invention;

FIG6 is a top view of a pole piece group being cut in a specific embodiment 7 of a method for manufacturing a battery cell according to the present invention;

In the figure: 1. first pole piece monomer; 2. second pole piece monomer; 3. isolation membrane; 4. pole piece unit; 5. cutter; 6. single piece cutter.

DETAILED DESCRIPTION

The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

A specific embodiment 1 of a battery cell manufacturing method of the present invention, as shown in Figures 1 to 5, includes a first electrode sheet, a second electrode sheet and an isolation membrane 3, wherein the first electrode sheet and the second electrode sheet have opposite polarities. In this embodiment, the first electrode sheet is a negative electrode sheet, including a negative electrode collector and a negative electrode active material, and the second electrode sheet is a positive electrode sheet, including a positive electrode collector and a positive electrode active material.

First, the first pole piece is cut into a plurality of first pole piece monomers 1, and then the plurality of first pole piece monomers 1 are placed between two consecutive isolation films 3 at equal intervals, and the two isolation films 3 are aligned with each other, and then the first pole piece and the two isolation films 3 are combined into one to form a pole piece group. In this embodiment, the first pole piece and the two isolation films 3 are adhered. Subsequently, the pole piece group is cut from the center of the interval between adjacent first pole piece monomers 1 with a cutter, and the pole piece group is cut into a plurality of pole piece units 4. In this embodiment, the positional relationship between the cutter and the pole piece group during cutting is shown in FIG. 3, and the cutter 5 is in a grid shape. The number of pole piece units obtained after one cutting by the cutter 5 is the same as the number of the first pole piece monomers.

The second pole piece is cut into a plurality of second pole piece monomers 2, the size of the second pole piece monomer 2 is slightly larger than the size of the first pole piece monomer 1, and then the pole piece unit 4 and the second pole piece monomer 2 are cross-stacked to form a stacking structure, and positive and negative pole ears are arranged on one side of the stacking structure or positive and negative pole ears are arranged on both sides of the stacking structure to form a battery cell.

The battery cell manufacturing method of the present invention combines the first pole piece and the two layers of isolation membrane 3 into one body and then cuts them into pole piece units 4, and then cross-stacks the cut pole piece units 4 and the cut second pole piece monomers 2. Compared with the existing stacked battery cells, not only the bending of the isolation membrane 3 and the centering process of the first and second pole pieces are omitted, thereby improving the production efficiency, but also the first pole piece and the isolation membrane 3 are combined into one body, even if the pole pieces are misaligned, short circuit will not occur, thereby improving the safety of the battery cell; in addition, the method of combining first and then cutting is adopted, which is not only convenient for cutting, but also only requires the first pole piece and the isolation membrane 3 to be aligned once during the entire pole piece unit 4 manufacturing process, without the need to align each cut first pole piece monomer 1 and the isolation membrane 3 again, thereby reducing the manufacturing process and further improving the production efficiency.

The first pole piece is cut into a plurality of first pole piece monomers 1 and then spaced between two layers of isolation membranes 3, and the pole piece group is cut from the intervals between adjacent first pole piece monomers 1, so that the area of the isolation membrane 3 after cutting is slightly larger than the area of the first pole piece monomer 1, so that the insulation between the first pole piece monomer 1 and the second pole piece monomer 2 can be better achieved.

The intervals between the first pole piece monomers 1 are equal, and the pole piece group is cut along the center line of the intervals between adjacent first pole piece monomers 1, so that the multiple pole piece units 4 obtained by cutting have the same shape and are arranged neatly.

The area of the second pole piece monomer 2 is greater than the area of the first pole piece monomer 1 , which can improve the energy density of the battery cell.

The difference between the specific embodiment 2 of the present invention and the specific embodiment 1 is that the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

The difference between the specific embodiment 3 of the present invention and the specific embodiment 1 is that the first pole piece can be placed as a whole between two layers of isolation films for compounding without being cut in advance, but the first pole piece and the isolation film can be cut simultaneously after compounding.

The difference between the specific embodiment 4 of the present invention and the specific embodiment 1 is that the area of the first pole piece monomer and the area of the second pole piece monomer are set to be consistent.

The difference between the specific embodiment 5 of the present invention and the specific embodiment 1 is that the first pole piece monomer and the isolation film may not be bonded together but may be fixed in other ways such as thermal bonding.

The difference between the specific embodiment 6 of the present invention and the specific embodiment 1 is that when the cutting mold is small, the number of pole piece units obtained by one cutting can be less than the number of the first pole piece monomers.

The difference between specific embodiment 7 of the present invention and specific embodiment 1 is that the cutter adopts a single-piece cutter 6, and the positional relationship between the single-piece cutter 6 and the pole piece group during the cutting process is shown in Figure 6. In this method, multiple first pole piece monomers are arranged in a row, and the single-piece cutter 6 cuts between two adjacent first pole piece monomers, and a pole piece unit is obtained after one cutting.

The specific embodiment of a method for manufacturing a pole piece unit of the present invention is the same as the method for manufacturing a pole piece unit in each embodiment of the above-mentioned method for manufacturing a battery cell, and will not be described in detail here.

A specific embodiment of a pole piece unit of the present invention includes an upper isolation membrane, a lower isolation membrane and a pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes. The cut surface of the upper and lower isolation membranes is cut once after the upper and lower isolation membranes are fixed to the pole piece monomer.

A specific embodiment of a battery cell of the present invention includes a pole piece unit and a second pole piece monomer cross-stacked with the pole piece unit, the pole piece unit includes an upper isolation membrane, a lower isolation membrane and a first pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes as a whole, the cut surface of the upper and lower isolation membranes is cut at one time after the two are fixed to the first pole piece monomer, and the first pole piece monomer and the second pole piece monomer have opposite polarities.

A specific embodiment of a battery of the present invention includes a battery cell, wherein the battery cell includes a pole piece unit and a second pole piece monomer cross-stacked with the pole piece unit, the pole piece unit includes an upper isolation membrane, a lower isolation membrane, and a first pole piece monomer located between the upper and lower isolation membranes and composited with the upper and lower isolation membranes as a whole, the cut surface of the upper and lower isolation membranes is cut at one time after the two are fixed to the first pole piece monomer, and the first pole piece monomer and the second pole piece monomer have opposite polarities.

Claims (18)

1. A pole piece unit characterized by: the pole piece unit comprises an upper isolating film, a lower isolating film, a pole piece unit and a pole piece unit, wherein the pole piece unit is positioned between the upper isolating film and the lower isolating film and is thermally compounded or bonded with the upper isolating film and the lower isolating film into a whole, and the cutting surfaces of the upper isolating film and the lower isolating film are formed by once cutting after the upper isolating film and the lower isolating film are fixed with the pole piece unit.

2. A manufacturing method of a pole piece unit is characterized in that: and arranging pole pieces between the two layers of isolation films, fixing the two layers of isolation films and the pole pieces to form a pole piece group, and cutting the pole piece group to obtain pole piece units, wherein the cut-off surfaces of the two layers of isolation films of the pole piece units are formed by cutting at one time.

3. A method of manufacturing a pole piece unit according to claim 2, characterized in that: the pole piece and the isolating film are fixed by compounding.

4. A method of manufacturing a pole piece unit according to claim 2, characterized in that: and cutting the pole piece into a plurality of pole piece monomers, then placing the pole piece monomers between two isolating films at intervals, and cutting the pole piece group from the intervals between the adjacent pole piece monomers.

5. A method of manufacturing a pole piece unit according to claim 4, characterized in that: the intervals between the adjacent pole piece monomers are equal, and the pole piece group is cut from the center line of the interval between the adjacent pole piece monomers.

6. A method of manufacturing a pole piece unit according to any of the claims 2-5, characterized in that: more than two pole piece units are obtained through one-time cutting.

7. A method of manufacturing a pole piece unit according to claim 6, characterized in that: the number of pole piece units obtained after one-time cutting is the same as the number of pole piece units.

8. The utility model provides an electric core which characterized in that: the pole piece unit comprises an upper isolation film, a lower isolation film and a first pole piece unit which is positioned between the upper isolation film and the lower isolation film and is thermally compounded or bonded with the upper isolation film and the lower isolation film into a whole, wherein the cut-off surfaces of the upper isolation film and the lower isolation film are formed by once cutting after the upper isolation film and the lower isolation film are fixed with the first pole piece unit, and the polarities of the first pole piece unit and the second pole piece unit are opposite.

9. The manufacturing method of the battery cell is characterized by comprising the following steps of: placing the first pole piece between two layers of isolating films and fixing the first pole piece with the two layers of isolating films to form a pole piece group; cutting the pole piece group into a plurality of pole piece units; the cutting surfaces of the two layers of isolating films of the pole piece units are cut at one time; cutting a second pole piece with polarity opposite to that of the first pole piece into a plurality of second pole piece monomers; the pole piece units and the second pole piece units are stacked in a crossing manner.

10. The method of manufacturing a cell according to claim 9, wherein: the first pole piece and the isolating film are fixed through compounding.

11. The method of manufacturing a cell according to claim 9, wherein: and cutting the first pole piece into a plurality of first pole piece monomers, then placing the first pole piece monomers between two isolating films at intervals, and cutting the pole piece group from the interval between the adjacent first pole piece monomers.

12. The method of manufacturing a cell according to claim 11, wherein: the intervals between the adjacent first pole piece monomers are equal, and the pole piece group is cut from the center line of the interval between the adjacent first pole piece monomers.

13. The cell manufacturing method according to any one of claims 9 to 12, wherein: more than two pole piece units are obtained through one-time cutting.

14. The method of manufacturing a cell according to claim 13, wherein: the number of pole piece units obtained after one-time cutting is the same as that of the first pole piece units.

15. The cell manufacturing method according to any one of claims 9 to 12, wherein: the area of the second pole piece monomer is larger than that of the first pole piece monomer.

16. The cell manufacturing method according to any one of claims 9 to 12, wherein: the positive electrode lug and the negative electrode lug of the battery cell are arranged on one side of the battery cell or on two sides of the battery cell respectively.

17. The method of manufacturing a cell according to claim 9, wherein: the first pole piece is adhered with the isolating film.

18. A battery comprising a cell, characterized in that: the battery cell comprises a pole piece unit and a second pole piece unit which is stacked in a crossing way with the pole piece unit, wherein the pole piece unit comprises an upper isolating film, a lower isolating film and a first pole piece unit which is positioned between the upper isolating film and the lower isolating film and is thermally compounded or bonded with the upper isolating film and the lower isolating film into a whole, the cut-off surfaces of the upper isolating film and the lower isolating film are formed by once cutting after the upper isolating film and the lower isolating film are fixed with the first pole piece unit, and the polarities of the first pole piece unit and the second pole piece unit are opposite.