CN108963191B - Preparation method of pole piece - Google Patents
Preparation method of pole piece Download PDFInfo
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- CN108963191B CN108963191B CN201810805470.3A CN201810805470A CN108963191B CN 108963191 B CN108963191 B CN 108963191B CN 201810805470 A CN201810805470 A CN 201810805470A CN 108963191 B CN108963191 B CN 108963191B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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Abstract
The invention provides a preparation method of a pole piece. The method comprises the following steps: and coating the pole piece slurry on a current collector by using a coating machine to obtain a pole piece, wherein the temperature and the wind speed are reduced when the coating machine is shut down. According to the preparation method of the pole piece, the temperature and the wind speed are reduced when the coating machine is stopped, so that the prepared pole piece can not be curled and cracked due to over-drying. Meanwhile, due to the fact that over-drying cannot be conducted in the coating process, the quality of the pole piece is guaranteed, and the reduction of bonding force and cycle performance caused by stopping and over-drying is avoided. In the preparation method, the temperature and the wind speed are reduced when the coating machine is stopped, so that the energy waste of electromechanics, steam and the like in the coating process is reduced, and the production cost is saved.
Description
Technical Field
The invention belongs to the technical field of battery manufacturing, and relates to a preparation method of a pole piece.
Background
The pole piece rolls up easily to appear when carrying out the coating single face in current lithium cell negative pole piece, and the edge fracture phenomenon appears easily when going out the oven, and the adhesion worsens appears when serious, and the pliability of pole piece is relatively poor. Particularly, when the machine is stopped midway, the heat in the oven is increased, and the cracking phenomenon is obviously aggravated.
In the prior art, a method of adding 1-3% of NMP into negative electrode slurry is adopted to improve the coating cracking phenomenon, but the residue of NMP in a pole piece can influence the performance of the battery, and the content of NMP cannot be detected by a Karl Fischer moisture test method commonly used by the conventional lithium battery, so that the production controllability increases risks.
CN107919459A discloses a preparation method of a lithium ion battery negative plate, the lithium ion battery negative plate and a lithium ion battery, wherein the preparation method of the lithium ion battery negative plate comprises the following steps: uniformly mixing the negative electrode material with water to prepare negative electrode slurry; the negative electrode material comprises a negative electrode active material, a conductive agent, a binder and an additive, wherein the mass ratio of the negative electrode active material to the conductive agent to the binder to the additive is 85.5-95.5:1-3:1.5-3.5: 2-8; the additive is at least one of ethylene carbonate and propylene carbonate; and coating the prepared negative electrode slurry on a negative electrode current collector, and drying to obtain the lithium ion battery. According to the preparation method of the lithium ion battery negative pole piece, the additive is added in the slurry mixing process, so that the problems of pole piece cracking, edge curling and the like after coating and drying can be reduced to the greatest extent, the qualification rate of the pole piece is greatly improved, and the reduction of battery performance caused by the quality of the pole piece is reduced.
CN108075103A discloses a process for manufacturing a pollution-free lithium ion battery cathode plate, which comprises the steps of (1) fully mixing and stirring a binder, a thickening agent, deionized water and a conductive agent according to a process proportion, and preparing an original slurry; (2) adjusting the process viscosity to be 5000-6000 mpa.s, and coating the slurry on the aluminum foil; (3) and during coating, the coating is carried out by adopting a coating mode of low air volume and constant temperature of 50-60 ℃ until the negative plate is finished. The scheme adopts low air volume during coating, so that a surface water layer can be slowly volatilized during baking of moisture in the slurry; the slurry adopts high viscosity, so that the thickness of a water layer in the slurry can be reduced, the water evaporation rate is consistent at a constant temperature of 50-60 ℃, and the high-quality negative plate without rolling, cracking and NMP waste gas pollution is prepared.
CN107134561A discloses a battery pole piece and a method for preventing the battery pole piece from curling, wherein the battery pole piece includes a metal current collector, one surface of the metal current collector is provided with an active material layer, and the other surface is provided with a polymer material layer. According to the scheme, the high polymer material layer is arranged on the surface, which is not required to be provided with the active material layer, of the metal current collector, so that the stress caused by extension of the active material after rolling can be offset or partially offset, and the problem of pole piece rolling caused after single-side coating rolling of the pole piece can be solved.
CN106960976A discloses a thin secondary battery and a method for manufacturing the same, wherein the thin secondary battery comprises at least one positive electrode plate and at least one negative electrode plate, the positive electrode plate and the negative electrode plate are sequentially arranged at intervals, each electrode plate comprises a metal current collector, characterized in that one side of the metal current collector in the outermost electrode plate facing other electrode plates is provided with an active material layer, and the other side is provided with a polymer material layer; when the number of the pole pieces is more than or equal to 3, the two surfaces of the metal current collector of the middle pole piece are both provided with active material layers. According to the scheme, only one side of the outermost pole piece of the thin secondary battery needs to be provided with the hot melt adhesive active material layer, the side, which does not need to be provided with the active material layer, of the metal current collector is provided with the polymer material layer, so that the stress caused by extension of the active material after rolling can be offset or partially offset, the problem of pole piece rolling caused after single-side coating rolling of the pole piece can be solved, and the pole piece can be thermally compounded with an aluminum-plastic composite packaging film of an outer package to form an integrated electrode.
Although the method can improve the problems of edge curling and cracking of the pole piece to a certain extent, the production cost is increased by adding additives or functional layers, or the coating efficiency is influenced by reducing the coating air volume in the whole process, which causes some difficulties in production practice.
Therefore, the development of a method which can solve the problems of pole piece curling and cracking in the pole piece coating process and is suitable for industrial mass production is of great significance to the field.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a preparation method of a pole piece. The preparation method of the pole piece can improve the phenomena of curling and cracking in the pole piece coating process, does not influence the performance of the battery, and is suitable for industrialized large-scale production.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a preparation method of a pole piece, which comprises the following steps:
and coating the pole piece slurry on a current collector by using a coating machine to obtain a pole piece, wherein the temperature and the wind speed are reduced when the coating machine is shut down.
In the pole piece coating process, coating machine roll changing, inspection and other reasons make coating machine halt inevitable, but pole piece curling and cracking phenomena caused by excessive drying when coating machine halt are ignored all the time. According to the preparation method of the pole piece, provided by the invention, the temperature and the wind speed are reduced when the coating machine is temporarily stopped, so that the pole piece cannot be curled and cracked due to over-drying in an oven of the coating machine. Meanwhile, due to the fact that over-drying cannot be carried out in the coating process, the quality of the pole piece is guaranteed, and the reduction of the adhesive force and the cycle performance caused by over-drying is avoided. In the preparation method, the temperature and the wind speed are reduced when the coating is stopped, and the energy waste of electromechanics, steam and the like in the coating process is also reduced.
In the present invention, the lowering of the temperature means that the temperature of most regions in the coater is lowered so that the coating temperature is lowered as a whole, but does not mean that the temperature of all regions in the coater is lowered.
The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.
In a preferred embodiment of the present invention, the temperature of the coating is 70 to 140 ℃, preferably 70 to 120 ℃ without stopping the coating machine, for example, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 130 ℃ or 140 ℃, but the coating is not limited to the recited values, and other values not recited in the range of the values are also applicable.
In a preferred embodiment of the present invention, the frequency of the fan is 20 to 40Hz, for example, 20Hz, 21Hz, 22Hz, 23Hz, 24Hz, 25Hz, 26Hz, 27Hz, 28Hz, 29Hz, 30Hz, 31Hz, 32Hz, 33Hz, 34Hz, 35Hz, 36Hz, 37Hz, 38Hz, 39Hz or 40Hz, but the present invention is not limited to the values listed, and other values not listed in the range of values are also applicable.
In a preferred embodiment of the present invention, the temperature of the coating at the time of shutdown is 60 to 100 ℃, for example, 50 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃, but the coating is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the temperature of the coating at shutdown is 20 ℃ or higher, for example 20 ℃, 25 ℃, or 30 ℃ or the like, lower than that at shutdown.
In a preferred embodiment of the present invention, the frequency of the fan for coating at the time of shutdown is 6 to 15Hz, for example, 6Hz, 7Hz, 8Hz, 9Hz, 10Hz, 11Hz, 12Hz, 13Hz, 14Hz, or 15Hz, but the present invention is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
As a preferred technical scheme of the invention, the coating machine comprises a plurality of drying ovens, and the temperature and the air speed of each drying oven are independently adjusted. The coating temperature and the air speed in the invention are adjusted by the oven.
Preferably, the number of ovens is 8-15, such as 8, 9, 10, 11, 12, 13, 14 or 15.
Preferably, the ovens are arranged in sequence from upstream to downstream of the coater. That is, in the present invention, the ovens in the coater are arranged one after another from the upstream to the downstream of the coater.
In the invention, the current collector coated with the pole piece slurry is dried from the upstream of the coating machine, passes through the midstream and leaves the coating machine from the downstream to finish coating, thus obtaining the pole piece.
Preferably, the oven temperature upstream of the coater is higher than the oven temperature upstream and downstream without stopping the coating. That is, the temperature of the oven near the upstream of the coater and the oven near the downstream of the coater is lower when the coating does not stop, while the temperature of the oven at the midstream of the coater is higher when the coating does not stop, and the temperature of the oven at the midstream is the coating temperature.
Preferably, the air speed of the oven at the midstream of the coater is higher than the air speeds of the oven at the upstream and downstream without stopping the coating. Namely, the air speed of the oven close to the upstream of the coating machine and the air speed of the oven close to the downstream of the coating machine are lower when the coating machine is not stopped, while the air speed of the oven at the midstream of the coating machine is higher when the coating machine is not stopped, and the air speed of the oven at the midstream is the coating air speed.
Preferably, the coating is stopped, and the temperature of the oven downstream of the coater is lowered.
Preferably, the air speed of each oven is the same when the coating is stopped.
Preferably, the air speed of all ovens of the coater is reduced when the coating is stopped.
Preferably, the temperature and the wind speed of the coating are automatically controlled by a program set for the coater.
As a preferable technical scheme of the invention, the duration of the shutdown is less than or equal to 4min, such as 4min, 3.5min, 3min, 2.5min, 2min, 1.5min or 1min, and the like, namely the shutdown with the duration less than or equal to 4min has little influence on the pole piece in coating, and can better ensure that the pole piece does not crack or curl. The roll change, the inspection, the exception handling and the like can be completely finished within 4min of shutdown.
As a preferable technical scheme of the invention, the pole piece slurry is a water-based negative pole piece slurry.
Preferably, the preparation method of the pole piece slurry comprises the following steps: and mixing the electrode active substance, the conductive agent, the binder and the solvent to obtain the pole piece slurry.
Preferably, the electrode active material includes graphite.
Preferably, the conductive agent includes any one of acetylene black, conductive carbon black, or carbon nanotubes, or a combination of at least two thereof.
Preferably, the binder comprises any one of or a combination of at least two of hydroxymethyl cellulose (CMC), Styrene Butadiene Rubber (SBR), or polyvinylidene fluoride (PVDF).
Preferably, the solvent comprises water.
Preferably, the mixing is stirred mixing.
As a preferable technical scheme of the invention, the current collector is a copper foil.
Preferably, the thickness of the current collector is 6-15 μm.
As a further preferable technical scheme of the preparation method, the method comprises the following steps:
coating the water-based negative pole piece slurry on a copper foil with the thickness of 6-15 mu m by using a coating machine, wherein the temperature of the coating without shutdown is 70-120 ℃, the frequency of a fan is 20-40Hz, the temperature is reduced to 60-100 ℃ when the coating is shutdown, the frequency of the fan is reduced to 6-15Hz, the shutdown duration is less than or equal to 4min, and obtaining a pole piece after the coating is finished;
the coating machine comprises 8-15 drying ovens, the temperature and the air speed of each drying oven are independently adjusted, the drying ovens are sequentially arranged from the upstream to the downstream of the coating machine, the temperature of the upstream drying oven is higher than that of the upstream drying oven and that of the downstream drying oven when the coating machine is not stopped, and the air speed of the upstream drying oven is higher than that of the upstream drying oven and that of the downstream drying oven; when the coating machine is stopped, the temperature of the baking oven in the midstream of the coating machine is reduced, the wind speeds of all the baking ovens of the coating machine are reduced, and the wind speeds of all the baking ovens are the same; the temperature and the wind speed of the coating are automatically controlled by a program set for the coating machine;
the preparation method of the aqueous negative pole piece slurry comprises the following steps: and stirring and mixing the electrode active substance, the conductive agent, the binder and water to obtain the aqueous negative electrode plate slurry.
Compared with the prior art, the invention has the following beneficial effects:
according to the preparation method of the pole piece, the temperature and the wind speed are reduced when the coating machine is stopped, so that the prepared pole piece can not be curled and cracked due to over-drying. Meanwhile, due to the fact that over-drying cannot be carried out in the coating process, the quality of the pole piece is guaranteed, and the reduction of the adhesive force and the cycle performance caused by over-drying is avoided. In the preparation method, the temperature and the wind speed are reduced when the coating machine is stopped, so that the energy waste of electromechanics, steam and the like in the coating process is reduced, and the production cost is saved.
Detailed Description
In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.
The following are typical but non-limiting examples of the invention:
example 1
In this embodiment, the pole piece is prepared according to the following method:
(1) mixing an electrode active material (graphite), a conductive agent (acetylene black) and a binder (SBR and CMC) with deionized water according to the mass fractions of 93% of graphite, 1% of conductive agent, 3% of SBR and 3% of CMC, and uniformly mixing the mixture by a stirrer to obtain a water-system negative pole piece slurry, wherein the viscosity of the water-system negative pole piece slurry is about 5000 CP.
(2) And (2) coating the water-based negative pole piece slurry prepared in the step (1) on copper foil with the thickness of 10 microns by using a coating machine, wherein the coating speed is 20m/min, the temperature is 70-100 ℃ when the coating is not stopped, the frequency of a fan is 20-30Hz, the temperature is reduced to 70-80 ℃ when the coating is stopped, the frequency of the fan is reduced to 10Hz, the temperature (namely the coating temperature) of most areas of the coating machine is 20 ℃ lower than that when the coating is not stopped, the stop duration is less than or equal to 4min, and the pole piece is obtained after the coating is finished.
The coating machine comprises 12 drying ovens, the temperature and the air speed of each drying oven are independently adjusted, the temperature and the air speed of coating are adjusted by the drying ovens, the drying ovens are sequentially arranged from the upstream to the downstream of the coating machine, the drying ovens are sequentially numbered from the upstream to the downstream as 1#, 2#, 3#, 4# to 12#, when the coating machine is not stopped, the temperature of the drying ovens at the midstream of the coating machine is higher than the temperature of the drying ovens at the upstream and the downstream, and the air speed of the drying ovens at the midstream of the coating machine is higher than the air speeds of the drying ovens at the upstream and the; when the coating machine is stopped, the temperature of each drying oven except the upstream drying ovens is the same, the wind speed of each drying oven is the same, the temperature of the drying oven at the midstream of the coating machine is reduced when the coating machine is stopped, the wind speed of all drying ovens of the coating machine is reduced, the temperature and the wind speed of the coating machine are automatically controlled through a program set for the coating machine, and the wind speed and the temperature of each drying oven can be automatically reduced through the program.
In this example, the temperature and the wind speed of each oven of the coater during coating without shutdown are shown in table 1, and the temperature and the wind speed of each oven during coating shutdown are shown in table 2.
TABLE 1
| Oven number | Temperature/. degree.C | Fan frequency/Hz |
| 1# | 70 | 20 |
| 2# | 80 | 20 |
| 3# | 90 | 25 |
| 4# | 100 | 25 |
| 5# | 100 | 30 |
| 6# | 100 | 30 |
| 7# | 100 | 30 |
| 8# | 100 | 30 |
| 9# | 100 | 25 |
| 10# | 90 | 25 |
| 11# | 85 | 25 |
| 12# | 80 | 25 |
TABLE 2
In this embodiment, the obtained pole piece does not crack or curl.
The downtime test was performed at the coating shutdown temperature and wind speed of this example, and the results are shown in table 3.
TABLE 3
| Down time | 1min | 2min | 3min | 4min | 5min |
| Cracking condition | Is free of | Is free of | Is free of | Light and slight | Is provided with |
As can be seen from Table 3, when the duration of the shutdown is less than or equal to 4min, the influence on the pole piece is very small.
Example 2
In this embodiment, the pole piece is prepared according to the following method:
(1) mixing an electrode active material (graphite), a conductive agent (acetylene black) and a binder (SBR and CMC) with deionized water according to the mass fractions of 97% of graphite, 0.7% of conductive agent, 1.8% of SBR and 1.5% of CMC, and uniformly mixing the mixture by a stirrer to obtain a water-system negative pole piece slurry, wherein the viscosity of the water-system negative pole piece slurry is about 5000 CP.
(2) And (2) coating the water-based negative pole piece slurry prepared in the step (1) on copper foil with the thickness of 6 microns by using a coating machine, wherein the coating speed is 20m/min, the temperature is 90-110 ℃ when the coating is not stopped, the frequency of a fan is 30-40Hz, the temperature is reduced to 50 ℃ when the coating is stopped, the frequency of the fan is reduced to 6Hz, the temperature (namely the coating temperature) of most regions of the coating machine is 60 ℃ lower than that when the coating is not stopped, the stop duration is less than or equal to 4min, and the pole piece is obtained after the coating is finished.
The coating machine comprises 8 drying ovens, the temperature and the wind speed of each drying oven are independently adjusted, the temperature and the wind speed of coating are adjusted by the drying ovens, the drying ovens are sequentially arranged from the upstream to the downstream of the coating machine, the drying ovens are sequentially numbered from the upstream to the downstream as 1#, 2#, 3#, 4# to 8#, when the coating machine is not stopped, the temperature of the drying ovens at the midstream of the coating machine is higher than the temperature of the drying ovens at the upstream and the downstream, and the wind speed of the drying ovens at the midstream of the coating machine is higher than the wind speeds of the drying ovens at the upstream and the; when the coating machine is stopped, the temperature of each drying oven is the same, the wind speed of each drying oven is the same, the temperature and the wind speed of the coating machine are automatically controlled through a program set by the coating machine, and the wind speed and the temperature of each drying oven can be automatically reduced through the program.
In this embodiment, the obtained pole piece does not crack or curl.
In this example, the temperature and the wind speed of each oven of the coater during coating without shutdown are shown in table 4, and the temperature and the wind speed of each oven during coating shutdown are shown in table 5.
TABLE 4
TABLE 5
| Oven number | Temperature/. degree.C | Fan frequency/Hz |
| 1# | 50 | 6 |
| 2# | 50 | 6 |
| 3# | 50 | 6 |
| 4# | 50 | 6 |
| 5# | 50 | 6 |
| 6# | 50 | 6 |
| 7# | 50 | 6 |
| 8# | 50 | 6 |
Example 3
In this embodiment, the pole piece is prepared according to the following method:
(1) mixing an electrode active material (graphite) and a binder (SBR and CMC) with deionized water according to the mass fractions of 95% of graphite, 2.5% of SBR and 2.5% of CMC, and uniformly mixing the mixture by a stirrer to obtain a water-system negative pole piece slurry, wherein the viscosity of the water-system negative pole piece slurry is about 1500 CP.
(2) And (2) coating the water-based negative pole piece slurry prepared in the step (1) on a copper foil with the thickness of 15 microns by using a coating machine, wherein the coating speed is 20m/min, the temperature when the coating is not stopped is 120-140 ℃, the frequency of a fan is 25-35Hz, the temperature when the coating is stopped is reduced to 100 ℃, the frequency of the fan is reduced to 15Hz, the temperature (namely the coating temperature) of most regions of the coating machine when the coating machine is stopped is 40 ℃ lower than that when the coating machine is not stopped, the stop duration is less than or equal to 4min, and obtaining the pole piece after the coating is finished.
The coating machine comprises 15 drying ovens, the temperature and the air speed of each drying oven are independently adjusted, the temperature and the air speed of coating are adjusted by the drying ovens, the drying ovens are sequentially arranged from the upstream to the downstream of the coating machine, the drying ovens are sequentially numbered from the upstream to the downstream to be 1#, 2#, 3#, 4# and 15#, when the coating machine is not stopped, the temperature of the drying ovens at the midstream of the coating machine is higher than the temperature of the drying ovens at the upstream and the downstream, and the air speed of the drying ovens at the midstream of the coating machine is higher than the air speeds of the drying ovens at the upstream and; when the coating machine is stopped, the temperature of each drying oven is the same, the wind speed of each drying oven is the same, the temperature and the wind speed of the coating machine are automatically controlled through a program set by the coating machine, and the wind speed and the temperature of each drying oven can be automatically reduced through the program.
In this embodiment, the obtained pole piece does not crack or curl.
In this example, the temperature and the wind speed of each oven of the coater during coating without shutdown are shown in table 6, and the temperature and the wind speed of each oven during coating shutdown are shown in table 7.
TABLE 6
TABLE 7
Example 4
Referring to example 1, the difference of the method for preparing the pole piece in the embodiment is that in the step (2), when the coating is not stopped, the temperature of each oven in the coating machine is the same and is 100 ℃; the wind speed of each drying oven in the coating machine is the same, and the frequency of the fan is 30 Hz.
The pole piece obtained by the embodiment does not crack or curl when the shutdown duration is less than or equal to 4min, but if the pole piece is set to be the same before and after the pole piece is normally coated and does not shut down, the floating adhesion force of SBR (styrene butadiene rubber) is reduced; 2. the surface layer of the pole piece is dried too fast in the initial drying of the pole piece, and the moisture of the inner layer is not easy to dry out, so that the surface layer and the internal difference of the pole piece greatly influence the performance of the product.
Comparative example 1
This comparative example method for manufacturing a pole piece refers to example 1 except that in step (2), the coating does not reduce the temperature and wind speed at the time of shutdown, but maintains the same temperature and wind speed as those at the time of shutdown.
As a result, the pole piece prepared in this comparative example cracked within 30 seconds of shutdown.
Comparative example 2
This comparative example method for manufacturing a pole piece refers to example 1 except that in step (2), the coating is not reduced in temperature at the time of shutdown, and the wind speed is reduced only in the manner of example 1, and the same temperature is maintained at the time of shutdown as that at the time of shutdown.
As a result, the pole piece prepared in this comparative example cracked within 50 seconds of shutdown.
Comparative example 3
The method for manufacturing a pole piece of this comparative example refers to example 1 except that in step (2), the coating does not reduce the wind speed at the time of shutdown, only reduces the temperature in the manner of example 1, and maintains the same wind speed at the time of shutdown as that at the time of shutdown.
As a result, the pole piece prepared in the comparative example cracks within 1min of shutdown.
By combining the above embodiments and comparative examples, the method for preparing the pole piece provided by the invention can reduce the temperature and the wind speed when the coating machine is stopped, so that the prepared pole piece can not be curled and cracked due to over-drying. Meanwhile, due to the fact that over-drying cannot be carried out in the coating process, the quality of the pole piece is guaranteed, and the reduction of the adhesive force and the cycle performance caused by over-drying is avoided. In the preparation method, the temperature and the wind speed are reduced when the coating machine is stopped, so that the energy waste of electromechanics, steam and the like in the coating process is reduced, and the production cost is saved. The comparative example did not adopt the scheme of the present invention, and thus the excellent effects of the present invention could not be obtained.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.
Claims (24)
1. A preparation method of a pole piece is characterized by comprising the following steps:
coating the pole piece slurry on a current collector by using a coating machine to obtain a pole piece, wherein the temperature and the wind speed are reduced when the coating machine is shut down;
the temperature of the coating during shutdown is lower than that of the coating during shutdown by more than 20 ℃, the duration of the shutdown is less than or equal to 4min, and the frequency of a fan during the coating during the shutdown is 6-15 Hz; the air speed of the oven at the midstream of the coating machine is higher than the air speeds of the oven at the upstream and downstream when the coating is not stopped.
2. The production method according to claim 1, wherein the temperature of the coating is 70 to 140 ℃ without stopping the machine.
3. The production method according to claim 2, wherein the temperature of the coating is 70 to 120 ℃ without stopping the machine.
4. The method of claim 1, wherein the frequency of the fan is 20-40Hz without shutdown of the coating.
5. The method of claim 1, wherein the temperature of the coating at shutdown is 50-100 ℃.
6. The production method according to claim 1, wherein the coater contains a plurality of ovens, and each oven independently adjusts the temperature and the air speed.
7. The method for preparing according to claim 6, wherein the number of the ovens is 8-15.
8. The production method according to claim 6, wherein the ovens are arranged in sequence from upstream to downstream of the coater.
9. The production method according to claim 6, wherein the oven temperature at the midstream of the coater is higher than the oven temperatures at the upstream and downstream without stopping the coating.
10. The production method according to claim 6, wherein the temperature of an oven at the midstream of the coater is lowered at the time of shutdown of the coating machine.
11. The method of claim 6, wherein the air speed is the same for each oven when the coating is stopped.
12. The method of claim 6, wherein the wind speed of all ovens of the coater is reduced during shutdown of the coating machine.
13. The manufacturing method according to claim 1, wherein the temperature and the wind speed of the coating are automatically controlled by a program set to a coater.
14. The preparation method according to claim 1, wherein the pole piece slurry is an aqueous negative pole piece slurry.
15. The preparation method of claim 1, wherein the preparation method of the pole piece slurry comprises the following steps: and mixing the electrode active substance, the conductive agent, the binder and the solvent to obtain the pole piece slurry.
16. The production method according to claim 15, wherein the electrode active material includes graphite.
17. The method according to claim 15, wherein the conductive agent comprises any one of acetylene black, conductive carbon black, or carbon nanotubes, or a combination of at least two thereof.
18. The method as claimed in claim 15, wherein the binder comprises any one or a combination of at least two of hydroxymethyl cellulose, styrene-butadiene rubber or polyvinylidene fluoride.
19. The method of claim 15, wherein the solvent comprises water.
20. The method of claim 15, wherein the mixing is stirring mixing.
21. The method of manufacturing according to claim 1, wherein the current collector comprises a copper foil and/or an aluminum foil.
22. The method of manufacturing of claim 21, wherein the current collector is a copper foil.
23. The manufacturing method according to claim 1, wherein the thickness of the current collector is 6 to 15 μm.
24. The method for preparing according to claim 1, characterized in that it comprises the following steps:
coating the water-based negative pole piece slurry on a copper foil with the thickness of 6-15 mu m by using a coating machine, wherein the temperature of the coating without shutdown is 70-120 ℃, the frequency of a fan is 20-40Hz, the temperature is reduced to 60-100 ℃ when the coating is shutdown, the frequency of the fan is reduced to 6-15Hz, the shutdown duration is less than or equal to 4min, and obtaining a pole piece after the coating is finished;
the coating machine comprises 8-15 drying ovens, the temperature and the air speed of each drying oven are independently adjusted, the drying ovens are sequentially arranged from the upstream to the downstream of the coating machine, the temperature of the upstream drying oven is higher than that of the upstream drying oven and that of the downstream drying oven when the coating machine is not stopped, and the air speed of the upstream drying oven is higher than that of the upstream drying oven and that of the downstream drying oven; when the coating machine is stopped, the temperature of the baking oven in the midstream of the coating machine is reduced, the wind speeds of all the baking ovens of the coating machine are reduced, the wind speeds of all the baking ovens are the same, and the temperature and the wind speed of the coating machine are automatically controlled through a program set for the coating machine;
the preparation method of the aqueous negative pole piece slurry comprises the following steps: and stirring and mixing the electrode active substance, the conductive agent, the binder and water to obtain the aqueous negative electrode plate slurry.
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| CN114289278A (en) * | 2021-11-19 | 2022-04-08 | 深圳市首通新能源科技有限公司 | Control method and device of battery core coating equipment |
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| CN101420026A (en) * | 2007-10-23 | 2009-04-29 | 比亚迪股份有限公司 | Manufacturing method for positive pole of lithium ionic cell |
| JP2015128876A (en) * | 2014-01-08 | 2015-07-16 | 株式会社リコー | Pre-treatment liquid coating dryer, printing system including the same, printing device |
| CN204656838U (en) * | 2015-05-20 | 2015-09-23 | 福建南平南孚电池有限公司 | A kind of drying channel of coating machine and adopt the coating machine of this drying tunnel |
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| CN103928686B (en) * | 2014-04-22 | 2017-05-03 | 深圳市振华新材料股份有限公司 | Self-scattering current collector, electrodes and lithium battery with current collector and application of current collector |
| CN207222279U (en) * | 2017-08-15 | 2018-04-13 | 东莞市创明电池技术有限公司 | Coating machine oven temperature-adjusting device and coating machine oven |
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| CN101420026A (en) * | 2007-10-23 | 2009-04-29 | 比亚迪股份有限公司 | Manufacturing method for positive pole of lithium ionic cell |
| JP2015128876A (en) * | 2014-01-08 | 2015-07-16 | 株式会社リコー | Pre-treatment liquid coating dryer, printing system including the same, printing device |
| CN204656838U (en) * | 2015-05-20 | 2015-09-23 | 福建南平南孚电池有限公司 | A kind of drying channel of coating machine and adopt the coating machine of this drying tunnel |
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