Large cylindrical lithium battery adopting laser scribing technology

Abstract

The invention belongs to the technical field of large cylindrical lithium batteries, particularly relates to a large cylindrical lithium battery adopting a laser scribing technology, and provides the following scheme that the large cylindrical lithium battery comprises a diaphragm, a positive plate, a negative plate, a laser scribing line and a roll core, the laser scribing line can be applied to the positive plate and the negative plate, and can be carved on a single-side plate; the lines can be scribed on both sides; the scribing angle E is selected from 0 degree to 90 degrees, the selection range of the scribing angle E is directly related to the material area width D of the pole piece, the wider the material area width D is, the larger the scribing angle E is in order to pursue the liquid injection speed, the narrower the material area width D is, and the smaller the scribing angle E is in order to pursue the infiltration effect. And the electrolyte injection time can be greatly shortened, meanwhile, the investment of electrolyte injection equipment is reduced, and the electrolyte infiltrates the battery well and has excellent cycle and rate charge-discharge performance.

Description

Technical Field

[0001] The invention relates to the technical field of large cylindrical lithium batteries, and in particular to a large cylindrical lithium battery using laser scribing technology. Background Art

[0002] With Tesla launching the 4680 large cylindrical battery, large cylindrical batteries are currently popular in the market.

[0003] As the battery diameter gradually increases, the wetting effect of the electrolyte gradually decreases, resulting in a long battery filling time and increased equipment costs. At the same time, poor electrolyte wetting effect will significantly affect the battery's cycle performance. Therefore, the present invention proposes a large cylindrical lithium battery using laser scribing technology to solve the above problems. Summary of the invention

[0004] Based on the background technology, as the battery diameter gradually increases, the wetting effect of the electrolyte gradually decreases, resulting in a long battery filling time and increased equipment costs. At the same time, the poor electrolyte wetting effect will significantly affect the battery's cycle performance and other technical problems. The present invention proposes a large cylindrical lithium battery using laser scribing technology.

[0005] The invention proposes a large cylindrical lithium battery using laser scribing technology, comprising a diaphragm, a positive electrode sheet, a negative electrode sheet, laser scribing and a winding core. The laser scribing can be applied to the positive electrode sheet or the negative electrode sheet, and can be scribed on a single side of the electrode sheet or on both sides.

[0006] The line angle E is selected between 0° and 90°. Its selection range is directly related to the material area width D of the electrode. The wider the material area width D, the larger the line angle E is to pursue the injection speed, and the narrower the material area width D is to pursue the wetting effect, the smaller the line angle E is. The range of D and E can be selected according to the following relationship:

[0007] D≤30mm,5° <E≤20°;

[0008] 30mm <D≤60mm,20°<E≤30°;

[0009] 60mm <D≤120mm,30°<E≤55°;

[0010] 120mm <D≤160mm,55°<E≤70°;

[0011] D>160mm,70° <E≤85°;

[0012] The smaller the line spacing L is, the shorter the injection time is. However, the smaller L is, the more lines there are, which affects the production efficiency of the line spacing process. The material area width D will also affect the size and production efficiency of the line spacing L. Its value can be selected as follows:

[0013] D≤60mm,10mm <L≤20mm;

[0014] 60mm <D≤120mm,20mm<L≤30mm;

[0015] 120mm <D≤160mm,30mm<L≤40mm;

[0016] D>160mm,40mm <L;

[0017] The width of the scribe line W, if its value is too small, it will lead to a long injection time, and if its value is too large, it will easily cause the battery performance to deteriorate. The width is suitable to be 200-300μm;

[0018] The smaller the score depth H is, the longer the injection time is. The larger the score depth H is, the shorter the injection time is. However, it is easy to penetrate the foil, resulting in performance degradation. The optional value is 1 / 3T≤H≤2 / 3T.

[0019] By means of the above mechanism: grooves are carved on the negative electrode sheet by laser, so that the electrolyte has an infiltration route, which can greatly shorten the injection time and reduce the investment in injection equipment. Batteries with good electrolyte infiltration have excellent cycle and rate charge and discharge performance.

[0020] Preferably, the specific manufacturing process of the positive electrode sheet is:

[0021] Positive electrode slurry: mix lithium iron phosphate or ternary materials and other materials to form a slurry;

[0022] Positive electrode coating: The slurry is coated on the positive electrode foil. After the slurry is dried, the positive electrode material is formed. There is positive electrode material on both sides of the foil, and finally a positive electrode sheet is formed;

[0023] Positive electrode rolling: rolling the positive electrode sheet to the thickness required by the process;

[0024] Positive electrode slitting: Slice the positive electrode sheet into the width required by the process.

[0025] Preferably, the manufacturing process of the negative electrode sheet is:

[0026] Mixing graphite and other materials to form a slurry;

[0027] Negative electrode coating: The slurry is coated on the negative electrode foil, and the slurry is dried to form the negative electrode material; the negative electrode material is present on both sides of the foil, and finally the negative electrode sheet is formed;

[0028] Negative electrode rolling: rolling the negative electrode sheet to the thickness required by the process;

[0029] Negative electrode cutting: Cut the negative electrode sheet into D electrode sheets with a width of ;

[0030] Negative electrode sheet engraving: Use laser to engrave the negative electrode material on the negative electrode sheet to form laser engraving lines.

[0031] Preferably, the manufacturing process of the winding core is:

[0032] The separator, the positive electrode sheet and the negative electrode sheet are wound to form a winding core, and the laser engraved lines serve as liquid guide holes after winding;

[0033] Core flattening: flatten the positive and negative foils of the core;

[0034] Collector plate welding and positive electrode encapsulation: Weld the positive and negative collector plates to the positive and negative electrodes of the winding core respectively, and wrap the positive electrode with high-temperature tape for one week;

[0035] Place the roll core into the casing.

[0036] Preferably, the shell is a steel shell, and the processing steps of the steel shell are:

[0037] Ultrasonic spot bottom welding: ultrasonically weld the negative electrode collector plate of the core to the steel shell; then groove the steel shell.

[0038] Liquid injection: The electrolyte flows along the laser engraving line and the direction indicated by the oblique arrow. Because it is a vertical injection, the electrolyte is affected by gravity and infiltrates into the battery cell along the direction indicated by the vertical arrow, which greatly reduces the injection time.

[0039] Cap welding: Laser welding the core positive electrode collector and the cap; then close the cap and seal it to make the battery;

[0040] Finally, the battery is cleaned, oiled, heat-shrunk and printed.

[0041] The beneficial effects of the present invention are:

[0042] The present invention uses laser to carve grooves on the negative electrode sheet so that the electrolyte has an infiltration route, which can greatly shorten the injection time and reduce the investment in injection equipment. The battery with good electrolyte infiltration has excellent cycle and rate charge and discharge performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the structure of a large cylindrical lithium battery using laser scribing technology proposed by the present invention;

[0044] Figure 2This is a schematic top view of the structure of a large cylindrical lithium battery using laser scribing technology proposed by the present invention;

[0045] Figure 3 This is a schematic cross-sectional view of the structure of a large cylindrical lithium battery using laser scribing technology proposed by the present invention;

[0046] Figure 4 This is a rotational and enlarged schematic diagram of the laser scribing of a large cylindrical lithium battery using laser scribing technology proposed in the present invention.

[0047] In the figure: 1. diaphragm; 2. positive electrode sheet; 21. positive electrode material; 22. positive electrode foil; 3. negative electrode sheet; 31. negative electrode material; 32. negative electrode foil; 4. laser engraving; 5. winding core. DETAILED DESCRIPTION

[0048] The present invention will be further explained below in conjunction with specific embodiments.

[0049] Example 1

[0050] refer to Figure 1-4 In this embodiment, a large cylindrical lithium battery using laser scribing 4 technology is proposed, including a diaphragm 1, a positive electrode sheet 2, a negative electrode sheet 3, laser scribing 4 and a winding core 5. The laser scribing 4 can be applied to the positive electrode sheet or the negative electrode sheet, and can be scribed on a single side of the electrode sheet or on both sides.

[0051] The line angle E is selected between 0° and 90°. Its selection range is directly related to the material area width D of the electrode. The wider the material area width D, the larger the line angle E is to pursue the injection speed, and the narrower the material area width D is to pursue the wetting effect, the smaller the line angle E is. The range of D and E can be selected according to the following relationship:

[0052] D≤30mm,5° <E≤20°;

[0053] 30mm <D≤60mm,20°<E≤30°;

[0054] 60mm <D≤120mm,30°<E≤55°;

[0055] 120mm <D≤160mm,55°<E≤70°;

[0056] D>160mm,70° <E≤85°;

[0057] The smaller the line spacing L is, the shorter the injection time is. However, the smaller L is, the more lines there are, which affects the production efficiency of the line spacing process. The material area width D will also affect the size and production efficiency of the line spacing L. Its value can be selected as follows:

[0058] D≤60mm,10mm <L≤20mm;

[0059] 60mm <D≤120mm,20mm<L≤30mm;

[0060] 120mm <D≤160mm,30mm<L≤40mm;

[0061] D>160mm,40mm <L;

[0062] The width of the scribe line W, if its value is too small, it will lead to a long injection time, and if its value is too large, it will easily cause the battery performance to deteriorate. The width is suitable to be 200-300μm;

[0063] The smaller the score depth H is, the longer the injection time is. The larger the score depth H is, the shorter the injection time is. However, it is easy to penetrate the foil, resulting in performance degradation. The optional value is 1 / 3T≤H≤2 / 3T.

[0064] By means of the above mechanism: grooves are carved on the negative electrode sheet 3 by laser, so that the electrolyte has an infiltration route, which can greatly shorten the injection time and reduce the investment in injection equipment. The battery with good electrolyte infiltration has excellent cycle and rate charge and discharge performance.

[0065] In this embodiment, the specific manufacturing process of the positive electrode sheet 2 is as follows:

[0066] Positive electrode slurry: mix lithium iron phosphate or ternary materials and other materials to form a slurry;

[0067] Positive electrode coating: the slurry is coated on the positive electrode foil 22, and the slurry is dried to form the positive electrode material 21, and the positive electrode material 21 is present on both sides of the foil, and finally the positive electrode sheet 2 is formed;

[0068] Positive electrode rolling: rolling the positive electrode sheet 2 to the thickness required by the process;

[0069] Positive electrode cutting: Cut the positive electrode sheet 2 into the width required by the process.

[0070] In this embodiment, the manufacturing process of the negative electrode sheet 3 is as follows:

[0071] Mixing graphite and other materials to form a slurry;

[0072] Negative electrode coating: the slurry is coated on the negative electrode foil 32, and the slurry is dried to form the negative electrode material 31; the negative electrode material 31 is present on both sides of the foil, and finally the negative electrode sheet 3 is formed;

[0073] Negative electrode rolling: rolling the negative electrode sheet 3 to the thickness required by the process;

[0074] Negative electrode cutting: cutting the negative electrode sheet 3 into a D electrode sheet with a width of ;

[0075] Negative electrode sheet 3 engraving: using laser, the negative electrode material 31 on the negative electrode sheet 3 is engraved to form laser engraved lines 4 .

[0076] In this embodiment, the manufacturing process of the winding core 5 is as follows:

[0077] The separator 1, the positive electrode sheet 2 and the negative electrode sheet 3 are wound to form a winding core 5. The laser engraved lines 4 function as liquid guide holes after winding.

[0078] Flattening the winding core 5: Flattening the positive and negative electrode foils 32 of the winding core 5;

[0079] Collector plate welding and positive electrode encapsulation: The positive and negative collector plates are welded to the positive and negative electrodes of the winding core 5 respectively, and the positive electrode is wrapped with high-temperature tape for one week;

[0080] The winding core 5 is placed into the housing.

[0081] In this embodiment, the outer shell is a steel shell, and the processing steps of the steel shell are:

[0082] Ultrasonic spot bottom welding: ultrasonically weld the negative electrode current collector of the winding core 5 to the steel shell; then groove the steel shell.

[0083] Liquid injection: The battery cell is injected with electrolyte, and the electrolyte flows along the laser engraved line 4 and in the direction indicated by the oblique arrow. Because the liquid is injected vertically, the electrolyte is affected by gravity and infiltrates into the battery cell in the direction indicated by the vertical arrow, which greatly reduces the injection time;

[0084] Cap welding: laser welding the positive electrode current collector of the winding core 5 to the cap; then closing the cap and sealing to obtain the battery;

[0085] Finally, the battery is cleaned, oiled, heat-shrunk and printed.

[0086] Example 2

[0087] Take the 40140 battery as an example for production;

[0088] 1. Lithium iron phosphate material is coated on the positive electrode foil 22, and the slurry is dried and then rolled and cut to obtain a pole piece; the coating width of the pole piece is 123.5 mm;

[0089] 2. The graphite material is coated on the negative electrode foil 32, and the slurry is dried and then rolled and cut to obtain a pole piece; the coating width of the pole piece is 126.5 mm, the total rolling thickness is 128 μm, and the thickness of the single-side material is 61 μm;

[0090] 3. Negative electrode sheet 3 scoring: Use laser to score the negative electrode sheet 3, score on both sides, with a depth of 30μm±10μm, a width of 250±50μm, a score spacing of 35±1mm, and a score angle of 60±2°;

[0091] 4. Winding: The separator 1, the positive electrode sheet 2, and the negative electrode sheet 3 are wound;

[0092] 5. Flattening the winding core 5: Flattening the positive and negative electrode foils 32 of the winding core 5;

[0093] 6. Current collector welding and positive electrode rubber coating: Weld the positive and negative current collectors to the positive and negative electrodes of the winding core 5 respectively, and wrap the positive electrode with high-temperature tape for one week;

[0094] 7. Enter the shell;

[0095] 8. Ultrasonic spot bottom welding: ultrasonically weld the negative electrode collector of the winding core 5 to the steel shell;

[0096] 9. Steel shell grooving;

[0097] 10. Liquid injection: Liquid injection process for the battery cell;

[0098] 11. Cap welding: Laser weld the positive electrode current collector of the winding core 5 with the cap;

[0099] 12. Close the cap and seal;

[0100] 13. Clean, oil and heat shrink the battery.

[0101] The following comparison uses the same type of battery to compare different engraving schemes:

[0102]

[0103]

[0104] From the above results, comparative example 1 has no engraved lines, a long injection time, and a short cycle life. In comparative example 8, although the injection time is the shortest, the engraved line spacing is small, the production efficiency is low, and the cycle life is not high.

[0105] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A large cylindrical lithium battery using laser scribing technology, comprising a diaphragm (1), a positive electrode sheet (2), a negative electrode sheet (3), laser scribing (4) and a winding core (5), characterized in that: The laser engraving (4) is applied to the positive electrode sheet and the negative electrode sheet, and can be engraved on one side of the electrode sheet or on both sides; The line angle E is selected between 0° and 90°. Its selection range is directly related to the material area width D of the pole piece. The wider the material area width D, the larger the line angle E, and the narrower the material area width D, the smaller the line angle E. The range of D and E can be selected according to the following relationship: D≤30mm,5° <E≤20°; 30mm <D≤60mm,20°<E≤30°; 60mm <D≤120mm,30°<E≤55°; 120mm <D≤160mm,55°<E≤70°; D>160mm,70° <E≤85°; The smaller the line spacing L is, the shorter the injection time is. However, the smaller L is, the more lines there are, which affects the production efficiency of the line spacing process. The material area width D will also affect the size and production efficiency of the line spacing L. Its value can be selected as follows: D≤60mm,10mm <L≤20mm; 60mm <D≤120mm,20mm<L≤30mm; 120mm <D≤160mm,30mm<L≤40mm; D>160mm,40mm <L; The width of the scribe line W is 200-300 μm; The depth of the engraving line H is selected to be 1 / 3T≤H≤2 / 3T.

2. A large cylindrical lithium battery using laser scribing technology according to claim 1, characterized in that: The specific manufacturing process of the positive electrode sheet (2) is as follows: Positive electrode slurry: mix lithium iron phosphate or ternary materials to form slurry; Positive electrode coating: coating the slurry on the positive electrode foil (22), and forming the positive electrode material (21) after the slurry is dried. The positive electrode material (21) is formed on both sides of the foil, and finally a positive electrode sheet (2) is formed; Positive electrode rolling: rolling the positive electrode sheet (2) to a thickness required by the process; Positive electrode slitting: Slice the positive electrode sheet (2) into the width required by the process.

3. A large cylindrical lithium battery using laser scribing technology according to claim 1, characterized in that: The manufacturing process of the negative electrode sheet (3) is as follows: Mixing graphite and other materials to form a slurry; Negative electrode coating: coating the slurry on the negative electrode foil (32), and forming the negative electrode material (31) after the slurry is dried; the negative electrode material (31) is formed on both sides of the foil, and finally forming the negative electrode sheet (3); Negative electrode rolling: rolling the negative electrode sheet (3) to a thickness required by the process; Negative electrode cutting: cutting the negative electrode sheet (3) into a D electrode sheet with a width of ; Negative electrode sheet (3) engraving: using a laser, engraving the negative electrode material (31) on the negative electrode sheet (3) to form laser engraved lines (4).

4. A large cylindrical lithium battery using laser scribing technology according to claim 1, characterized in that: The manufacturing process of the winding core (5) is as follows: The separator (1), the positive electrode sheet (2) and the negative electrode sheet (3) are wound to form a winding core (5), and laser marking lines (4) are formed after the winding; Flattening the winding core (5): Flattening the positive and negative electrode foils (32) of the winding core (5); Collector plate welding and positive electrode encapsulation: the positive and negative collector plates are welded to the positive and negative electrodes of the winding core (5) respectively, and the positive electrode is wrapped with high-temperature tape for one week; Place the core (5) into the casing.

5. A large cylindrical lithium battery using laser scribing technology according to claim 4, characterized in that: The shell is a steel shell, and the processing steps of the steel shell are: Ultrasonic spot bottom welding: ultrasonically weld the negative electrode current collector of the winding core (5) to the steel shell; then groove the steel shell. Liquid injection: The electrolyte flows along the laser engraved line (4) in the direction indicated by the oblique arrow. Because the electrolyte is injected vertically, the electrolyte is affected by gravity and infiltrates into the battery cell in the direction indicated by the vertical arrow, which greatly reduces the injection time. Cap welding: laser welding the positive electrode current collecting plate of the winding core (5) and the cap; then closing the cap and sealing the battery; Finally, the battery is cleaned, oiled, heat-shrunk and printed.

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