Slit extrusion coating pump speed calculation method, coating method, negative plate and lithium ion battery

Abstract

The invention belongs to the field of battery preparation, and particularly relates to a slit extrusion coating pump speed calculation method, a coating method, a negative plate and a lithium ion battery. The slit extrusion coating pump speed calculation method is obtained by correcting the compensation value of the theoretical pump speed; r '= e + R, R' is the actual pump speed, e is the compensation value, and R is the theoretical pump speed. The lithium battery slit extrusion coating pump speed calculation method can accurately assist professional technicians in accurately setting the coating pump speed, and can effectively reduce the trial coating frequency of production debugging personnel and reduce the difference between the actual pump speed and the trial coating frequency in combination with offline actual measurement detection.

Description

Technical Field

[0001] The invention belongs to the field of battery preparation, and in particular relates to a slit extrusion coating pump speed calculation method, a coating method, a negative electrode sheet and a lithium ion battery. Background Art

[0002] At present, the coating process of lithium-ion battery pole pieces is a process based on the study of the physical properties of fluid slurry. One or more layers of slurry are evenly coated on the current collector. The current collector is usually a flexible film or metal foil. The coated coating is then dried in an oven to form a coating with uniform surface density and uniform thickness.

[0003] The main coating method at present is slit extrusion coating, which is a set screw pump speed. Through a stable and uniform quantitative method, the stator and rotor in the screw pump rotate and the slurry is pumped into the inner cavity of the extrusion die. The slurry is then sprayed out from the slit gap of the die to make it evenly coated on the current collector. Therefore, the precise setting of the pump speed is a key link in the consistency of the electrode.

[0004] At present, the pump speed setting of the lithium battery coating process is carried out by technicians based on their own experience. The fuzzy setting of the pump speed is not accurate enough and has large errors. It cannot accurately reflect the pump speed corresponding to the designed surface density. The production debugging times are large, the debugging efficiency is low, and the amount of scrapped pole pieces is large. In addition, each time the surface density or size is changed and the solid content of the incoming material fluctuates greatly, re-testing is required, which increases the labor intensity of production personnel, increases the output of scrapped products, and reduces the production yield. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for calculating the pump speed of a slit extrusion coating, a coating method, a negative electrode sheet and a lithium ion battery.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for calculating the pump speed of slot extrusion coating is provided, wherein the theoretical pump speed is corrected by a compensation value; R'=e+R, wherein R' is the actual pump speed, e is the compensation value, and R is the theoretical pump speed.

[0008] The theoretical pump speed R = [(V*B*L*N) / G*ρ*A] / 100; wherein B is the designed single-sided surface density, V is the slurry coating speed provided by the coating equipment; L is the theoretical coating width, N is the theoretical number of coating strips, G is the single-turn throughput of the screw pump, ρ is the actual slurry density, and A is the actual slurry solid content.

[0009] The compensation value e=BR / bR; wherein B is the designed single-surface surface density, b is the actual output single-surface surface density, and R is the theoretical pump speed.

[0010] The present invention also includes a slurry coating method, based on the lithium battery slit extrusion coating pump speed calculation method, including the following steps: setting a first parameter of a coater and obtaining a slurry parameter; setting a coating target as a second parameter, obtaining a theoretical pump speed R based on the first parameter, the slurry parameter and the second parameter, correcting the theoretical pump speed R by a compensation value e through the actual output electrode surface density to obtain an actual pump speed R', and coating on the current collector according to the actual pump speed R'.

[0011] The first parameters include the slurry coating speed V provided by the coating equipment and the single-turn throughput G of the screw pump.

[0012] The slurry parameters include ρ for the actual slurry density and A for the actual slurry solid content.

[0013] The second parameters include the designed single-sided surface density B, the coating width L, and the number of coating strips N.

[0014] The correction method is the actual pump speed R'=e+R, where the compensation value e=BR / bR, B is the designed electrode single surface density, b is the actual output electrode surface density, and R is the theoretical pump speed.

[0015] The present invention also includes a negative electrode sheet, which is prepared by coating the slurry onto a current collector using the coating method.

[0016] The present invention also includes a lithium ion battery, comprising the negative electrode sheet.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention discloses a method for calculating the pump speed of lithium battery slit extrusion coating, which can accurately assist professional and technical personnel in accurately setting the coating pump speed. Combined with offline actual measurement and detection, it can effectively reduce the number of trial coatings by production and debugging personnel and narrow the gap with the actual pump speed. Moreover, each time the surface density or size is switched or the solid content of the incoming material fluctuates greatly, no large fluctuation will occur, thereby reducing the scrapping of pole pieces generated during the debugging process, reducing the labor intensity of production personnel, and improving the yield rate of the coating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Output pole piece surface density result plot for pump speed. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and the best embodiments.

[0021] A method for calculating the pump speed of slot extrusion coating is provided, wherein the theoretical pump speed is corrected by a compensation value; R'=e+R, wherein R' is the actual pump speed, e is the compensation value, and R is the theoretical pump speed.

[0022] The theoretical pump speed is [(V*B*L*N) / G*ρ*A] / 100; wherein B is the designed single-sided surface density, V is the slurry coating speed provided by the coating equipment, L is the theoretical coating width, N is the theoretical number of coating strips, G is the single-turn throughput of the screw pump, ρ is the actual slurry density, and A is the actual slurry solid content.

[0023] As a form of embodiment, the actual slurry density in this application is ρ1.39 g / cm 3 , actual slurry solid content A55%; pole piece design single surface density B 10.25±0.15mg / cm 2 , coating width L 156mm, number of coating strips N 2; coating speed V 10m / min, screw pump single-turn throughput G 32ml.

[0024] R=[(V*B*L*N) / G*ρ*A] / 100=13.1 (rpm)

[0025] The compensation value e=BR / bR; where B is the designed single-sided surface density, b is the actual output single-sided surface density, R is the theoretical pump speed, and b is 10 mg / cm 2 ;

[0026] Calculate the compensation value e=BR / bR=0.33;

[0027] The actual pump speed value R'=e+R=13.43;

[0028] A method for coating slurry based on a slit extrusion coating pump speed calculation method comprises the following steps: setting a first parameter of a coating machine and obtaining a slurry parameter; setting a coating target as a second parameter, obtaining a theoretical pump speed R based on the first parameter, the slurry parameter and the second parameter, correcting the theoretical pump speed R by a compensation value e according to the actual output electrode surface density to obtain an actual pump speed R', and coating on a current collector according to the actual pump speed R'.

[0029] The first parameter includes the slurry coating speed V provided by the coating equipment and the single-turn throughput G of the screw pump. The slurry parameters include ρ for the actual slurry density and A for the actual slurry solid content. The second parameter includes the designed single-sided surface density B, the coating width L, and the number of coating strips N. The correction method is the actual pump speed R'=e+R, where the compensation value e=BR / bR, B is the designed electrode single-sidedness, b is the actual output electrode surface density, and R is the theoretical pump speed.

[0030] The actual slurry density in this application is ρ1.39 g / cm3 , actual slurry solid content A 55%; pole piece design single surface density B 10.25±0.15mg / cm 2 , coating width L 156mm, number of coating strips N 2; coating speed V 15m / min, screw pump single-turn throughput G 32ml.

[0031] R=(V*B*L*N) / G*ρ*A=13.1 (rpm)

[0032] Compensation value e = BR / bR; where B is the designed single-sided surface density, b is the actual output single-sided surface density, R is the theoretical pump speed, and b is 10 mg / cm 2 ;

[0033] Calculate the compensation value e=BR / bR=0.33;

[0034] Adjust the coating pump speed to output the actual pump speed value R'=13.43, and verify that the surface density of the electrode produced at this pump speed is consistent with the actual measured value of the offline line. For details, see the attached Figure 1 , the results show that its overall fluctuations are in line with expectations.

[0035] The present invention also includes a negative electrode sheet, which is prepared by coating the slurry onto a current collector using the coating method. The present invention also includes a lithium ion battery, which includes the negative electrode sheet.

[0036] The present invention forms a more accurate pump speed calculation method by theoretically deriving product information such as incoming material density, solid content, coating width and equipment operating parameters, and further accurately obtains the pump speed by compensating and correcting the measured data and the debugging pump speed. The present invention does not need to add a constant coefficient to participate in the pump speed calculation through data fitting, which reduces the understanding threshold of actual operators and can directly guide production debugging. Its simplicity and accuracy are in sharp contrast with other methods.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating the pump speed of slot extrusion coating, characterized in that: The theoretical pump speed is corrected by the compensation value to obtain: R'=e+R, where R' is the actual pump speed, e is the compensation value, and R is the theoretical pump speed.

2. The method for calculating the pump speed of lithium battery slot extrusion coating according to claim 1, characterized in that: The theoretical pump speed R = [(V*B*L*N) / G*ρ*A] / 100; wherein B is the designed single-sided surface density, V is the slurry coating speed provided by the coating equipment; L is the theoretical coating width, N is the theoretical number of coating strips, G is the single-turn throughput of the screw pump, ρ is the actual slurry density, and A is the actual slurry solid content.

3. The method for calculating the pump speed of lithium battery slot extrusion coating according to claim 1, characterized in that: The compensation value e=BR / bR; wherein B is the designed single-surface surface density, b is the actual output single-surface surface density, and R is the theoretical pump speed.

4. A slurry coating method, characterized in that: A method for calculating the pump speed of lithium battery slot extrusion coating based on any one of claims 1 to 3; The method comprises the following steps: setting a first parameter of a coating machine and obtaining a slurry parameter; setting a coating target as a second parameter, obtaining a theoretical pump speed R based on the first parameter, the slurry parameter and the second parameter, correcting the theoretical pump speed by a compensation value e according to the actual output electrode surface density to obtain an actual pump speed R', and coating on the current collector according to the actual pump speed R'.

5. The coating method according to claim 4, characterized in that The first parameters include the slurry coating speed V provided by the coating equipment and the single-turn throughput G of the screw pump.

6. The coating method according to claim 4, characterized in that: The slurry parameters include ρ for the actual slurry density and A for the actual slurry solid content.

7. The coating method according to claim 4, characterized in that: The second parameters include the designed single-sided surface density B, the coating width L, and the number of coating strips N.

8. The coating method according to claim 4, characterized in that: The correction method is the actual pump speed R'=e+R, where the compensation value e=BR / bR, B is the designed electrode single surface density, b is the actual output electrode surface density, and R is the theoretical pump speed.

9. A negative electrode sheet, characterized in that: The slurry is coated on a current collector using the coating method described in any one of claims 4 to 8 to obtain the coating.

10. A lithium ion battery, characterized in that: Including the negative electrode sheet as claimed in claim 9.

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