CN115275112A - Negative plate baking process, negative plate and lithium battery - Google Patents

Negative plate baking process, negative plate and lithium battery Download PDF

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Publication number
CN115275112A
CN115275112A CN202210912181.XA CN202210912181A CN115275112A CN 115275112 A CN115275112 A CN 115275112A CN 202210912181 A CN202210912181 A CN 202210912181A CN 115275112 A CN115275112 A CN 115275112A
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negative
negative electrode
baking process
oven
thickness
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Inventor
林陈能
陈金苹
王�华
杜双龙
苑丁丁
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Hubei Eve Power Co Ltd
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Hubei Eve Power Co Ltd
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Priority to CN202210912181.XA priority Critical patent/CN115275112A/en
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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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B13/00—Machines and apparatus for drying fabrics, fibres, yarns, or other materials in long lengths, with progressive movement
    • F26B13/10—Arrangements for feeding, heating or supporting materials; Controlling movement, tension or position of materials
    • F26B13/14—Rollers, drums, cylinders; Arrangement of drives, supports, bearings, cleaning
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • 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
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Textile Engineering (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention relates to the technical field of lithium battery preparation, and discloses a negative plate baking process, a negative plate and a lithium battery, wherein the negative plate baking process comprises the following steps: s1: providing a rolled negative electrode coil, and carrying out feeding operation on the negative electrode coil in a coating machine; s2: unreeling the negative electrode coil to enable the negative electrode belt to enter an oven; s3: adjusting the temperature and the tape-feeding speed of the oven, and baking the negative tape; s4: and carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain the negative electrode plate. Through the cathode plate baking process, all positions of the cathode plate are uniformly heated and stressed in the baking operation, so that the internal stress of the cathode plate is uniformly released and the thickness of the cathode plate is fully rebounded, the baked cathode plate has high thickness consistency, and the defect rate of dislocation of the tabs caused by uneven thickness is reduced.

Description

Negative plate baking process, negative plate and lithium battery
Technical Field
The invention relates to the technical field of lithium battery preparation, in particular to a negative plate baking process, a negative plate and a lithium battery.
Background
In the production process of the lithium ion battery, the pole piece manufacture belongs to a front-stage process and occupies an important position in the whole process. The quality of the pole piece is related to the assembly process of the middle section of the lithium battery, and the electrochemical performance of the back section and the lithium battery is also influenced.
A baking process (rolling → pole piece baking → die cutting) is added after the lithium ion battery negative pole piece is rolled, on one hand, the baking process enables the thickness rebound rate of the negative pole piece before winding after the negative pole piece is rolled to be maximum, so that the physical internal stress among negative pole material particles after rolling is completely released, the negative pole piece thickness rebound caused by the physical internal stress during charging of the battery is eliminated, the positive pole piece and the negative pole piece are ensured to be contacted more tightly, the lithium ion migration path is shortened, so that the cycle performance of the battery is improved, on the other hand, the porosity of the negative pole piece can be effectively improved by the sufficient rebound of the thickness after the negative pole piece is rolled, so that the electrolyte infiltration effect is improved, the problem of reaction heat caused by insufficient infiltration of electrolyte in the charging and discharging process is effectively solved, and the cycle performance of the battery is improved.
At present, a baking process in the industry is mainly performed by winding a negative plate into a negative plate coil, but when the required plate is longer and the number of layers of the coil core is more, the inner layer and the outer layer of the negative plate coil are easily heated unevenly in the baking process, so that the baking effect is directly different, the stress release and thickness rebound degree of the negative plate are different, and the consistency of the thickness and the internal stress of the plate is poor; in addition, the baking process of the pole rolls needs to be newly built with a high-temperature baking room, so that the production cost is increased.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides the negative plate baking process, which adopts a mode of baking a single-layer negative plate strip and improves the consistency of the thickness rebound and the internal stress release of the baked negative plate.
The invention also aims to provide the negative plate prepared by the negative plate baking process.
It is still another object of the present invention to provide a lithium battery comprising the above negative electrode sheet.
The purpose of the invention is realized by the following technical scheme:
the negative plate baking process is characterized by comprising the following steps of:
s1: providing a rolled negative electrode coil, and carrying out feeding operation on the negative electrode coil in a coating machine;
s2: unreeling the negative electrode coil to enable the negative electrode belt to enter an oven;
s3: adjusting the temperature and the tape speed of the oven to carry out baking operation;
s3: adjusting the temperature and the tape-moving speed of the oven, and baking the negative tape;
s4: and carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain the negative electrode sheet.
Further, the oven is provided with a roller, the negative pole belt is in contact with the roller, and the roller is subjected to balance adjustment before the baking operation.
Furthermore, the negative pole belt comprises a coating area and a pole lug area positioned at one end of the coating area, and a pole lug pad high ring is arranged at the contact position of the roll and the pole lug area.
Furthermore, the thickness of the pole ear pad high ring is 5-10 μm smaller than the thickness of the single-side coating of the negative pole belt.
Further, the polar ear pad high ring is arranged at a position 0.5-2.0 mm away from the coating area.
Further, the tab heightening ring is obtained by winding a smooth soft adhesive tape on the roller.
Further, the temperature of the oven is 90-110 ℃.
Further, the length of the oven is 35-150 m, and the belt travelling speed is 5-25 m/min.
The invention also provides the negative plate which is prepared by the negative plate baking process and has good thickness consistency.
The invention finally provides a lithium battery adopting the negative plate, and the lithium battery has good cycle stability.
Compared with the prior art, the invention has at least the following advantages:
1. the baking process of the negative pole piece is different from the traditional mode of directly baking the negative pole roll, the negative pole roll is unreeled by adopting equipment, and the negative pole belt is conveyed into the baking oven to be baked.
2. The cathode plate baking process provided by the invention can be directly carried out by using the existing coating machine equipment, does not need to purchase new equipment or build a high-temperature baking room, has low cost and is suitable for industrial popularization and application.
Drawings
Fig. 1 is a flowchart of a baking process of the negative electrode plate in example 1 of the present invention.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
The tradition adopts and sends into whole negative pole extremely book the drying in the oven, just as in the foretell negative pole extremely book inlayer and outer negative pole piece because be heated inhomogeneously, lead to finally toasting the negative pole piece thickness uniformity after poor easily, the influence of the uneven problem of thickness especially to coiling formula lithium cell is great. The method is characterized in that the winding process is required to be carried out in the preparation of the winding type lithium battery, wherein when one layer is added, the thickness of a core package is increased by one unit (2 layers of diaphragms, one layer of positive electrode and one layer of negative electrode), the thickness of a positive plate and the thickness of the diaphragms are basically fixed, the negative plate is easy to release insufficiently because of internal stress, the thickness fluctuation of the negative plate wound in different time periods is large, the thickness of the core package added by one layer is different when winding is caused, the thickness consistency is poor, meanwhile, the position of a tab after die cutting of the plate is fixed, when the thickness is thicker, the tab can deviate against the winding direction, when the thickness is thinner, the tab can deviate along the winding direction, the tab dislocation is caused, and only when the thickness of the negative plate is stable, the consistency of the thickness of the winding core package can be improved, and the tab dislocation can be reduced.
Therefore, the thickness consistency of the negative plate is a key factor influencing the performance of the lithium battery, and in order to improve the thickness consistency of the negative plate, the invention provides the negative plate baking process, the traditional process of baking the whole negative plate coil is abandoned, the single-layer negative belt is uniformly baked after the negative plate coil is uncoiled, the maximum rebound value of the negative plate during coiling is ensured through high-temperature acceleration, the internal stress of the negative plate is uniformly released to fully rebound the negative plate, the thickness consistency of the negative plate is improved, and therefore, the thickness consistency of the coiling core cladding is improved, and the dislocation of the tabs is reduced.
Referring to fig. 1, the baking process of the negative electrode plate provided by the present invention includes the following steps:
s1: and providing a rolled negative electrode coil, and feeding the negative electrode coil on a coating machine.
It should be noted that, current coating machine generally includes unwinding mechanism, direction/tension adjustment mechanism, coating mechanism, stoving mechanism, winding mechanism, and the coating and the drying of pole piece are realized to a plurality of mechanism combined action, adopt current coating machine to realize negative pole piece toasts technology in this application, toast with current negative pole utmost point book need purchase new equipment and build high temperature bakery and compare, have low cost, be favorable to the characteristics of popularization. In the process of baking the rolled negative electrode coil by adopting a coating machine, the unwinding mechanism and the winding mechanism are positioned at two ends of the drying mechanism, and the transmission of the negative electrode strip in the drying mechanism is realized under the driving action of the unwinding mechanism and the winding mechanism; the guide mechanism generally comprises a plurality of roller passing devices, and the roller passing devices are related to the belt traveling direction, the balance degree and the pole piece tension of the negative pole belt; the drying mechanism and the oven are required to have a heating function and a heating channel with a certain length.
In the step S1, the feeding operation includes transporting the rolled negative electrode coil to an unwinding mechanism, and then performing negative electrode tape threading.
S2: and unreeling the negative electrode coil to enable the negative electrode belt to enter an oven.
Further, the oven is provided with a roller, the negative strip is in contact with the roller, and the roller is subjected to balance adjustment before the baking operation.
It should be noted that, a plurality of rollers are arranged in a common oven, the negative electrode belt is stably conveyed under the guiding action of the rollers, and before the baking operation, the roller is subjected to balance adjustment, so that uneven tension of the negative electrode belt in different areas in the belt conveying process due to the inclination of the rollers is prevented, and deformation of the negative electrode belt due to the uneven tension is avoided, and the yield of the final negative electrode sheet is influenced.
The balance adjustment comprises the following steps: the parallelism adjustment is carried out by adjusting the levelness adjusting screw on the left side of the roller, and the air bubbles of the level meter are adjusted to be parallel to the central position. If the bubble is centered, no adjustment is needed; if the bubble is offset to the left, the adjustment screw adjusts the left side of the roller downward until the bubble is centered.
Furthermore, the negative pole belt comprises a coating area and a pole lug area positioned at one end of the coating area, and a pole lug pad high ring is arranged at the contact position of the roll and the pole lug area.
It should be noted that, before the negative electrode strip is subjected to the die cutting and slitting processes, the pole ear area is continuous and uninterrupted, and because the thickness of the coating area is larger than that of the pole ear area, the cylindrical roller is difficult to adjust the tension of the coating area and the tension of the pole ear area at the same time, the pole ear area is easy to turn over and wrinkle in the baking process, so that a pole ear pad high ring is arranged at the position of the roller, which is in contact with the pole ear area, so that the height difference between the coating area and the pole ear area in the process of taking the negative electrode strip away is reduced, and the pole ear area can be ensured to be flat and free of wrinkling.
Furthermore, the thickness of the high ring of the electrode ear pad is 5-10 μm smaller than the thickness of the single-side coating of the negative plate.
It should be noted that, the common negative plate is coated on both sides of the current collector, and the tab is disposed between the two coatings, so that in the roll-passing process, the height difference between the coating area and the tab area is actually the thickness of the negative plate single-side coating, the thickness of the tab high ring is set to be 5-10 μm smaller than the thickness of the negative plate single-side coating, so as to ensure that the tab is fully stretched in the roll-passing process to prevent wrinkling, and meanwhile, the thickness difference is reserved for tension release, so as to prevent the tab from breaking due to too large tension in the roll-passing process.
Further, the polar ear pad high ring is arranged at a position 0.5-2.0 mm away from the coating area.
The arrangement can enable the tab heightening ring to be close to the coating area as much as possible, ensure that the root of the tab area is fully stretched, and prevent the coating from falling off due to the fact that the tab heightening ring is scraped and rubbed against the coating area due to corrosion.
Further, the tab heightening ring is obtained by winding a smooth soft adhesive tape on the roller.
It should be noted that smooth soft adhesive tape is adopted to wrap around the roller to prepare the tab heightening pad, the thickness of the tab heightening ring can be flexibly adjusted according to the negative plates with different thicknesses, and meanwhile, the smooth soft adhesive tape is adopted to reduce the friction between the tab heightening ring and the tab area and prevent the deformation of the tab area caused by the excessive hardness and the excessive roughness of the material of the tab heightening ring.
Furthermore, the smooth soft adhesive tape can be made of Teflon adhesive tape.
The Teflon adhesive tape has the advantages of high strength, high temperature resistance, smooth surface, good adhesion resistance, electric insulation performance and the like, and the Teflon adhesive tape is a good choice for forming the high ring of the polar ear pad by winding the Teflon adhesive tape around a roller.
Further, the air outlet direction of the air nozzle of the drying oven is adjusted to enable the air outlet direction to face the coating area.
It should be noted that, in order to improve the heating uniformity inside the oven, the existing coating machine oven is generally provided with a blowing mechanism, and in the technical scheme of the invention, the air outlet direction of the air nozzle is adjusted, that is, the angle of the air nozzle is adjusted to incline 30-60 degrees towards the coating area, so that the phenomenon that the air nozzle directly blows to the tab area to cause tab folding and wrinkling is avoided.
S3: and adjusting the temperature of the oven and the speed of the belt, and baking the negative belt.
Further, the temperature of the oven is 90-110 ℃.
It should be noted that the temperature of the oven needs to be adjusted within the range of 90-110 ℃, so that the phenomenon that the pole piece cannot rebound fully due to expansion caused by heat and contraction caused by cold and completely release internal stress is prevented, and meanwhile, the decomposition failure of coating auxiliary materials (CMC and SBR) with overhigh temperature is avoided, and the adhesive force of the coating is reduced.
Further, the length of the oven is 35-150 m, and the belt travelling speed is 5-25 m/min.
It should be noted that the tape transport speed is adjusted according to the length of the oven, so that the time for the negative tape to pass through the oven is properly controlled within 1-5 min, i.e. the baking time is controlled within 1-5 min.
S4: and carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain the negative electrode sheet.
It should be noted that, in order to facilitate the transportation of the negative electrode tape, the baked negative electrode tape is wound by the winding mechanism and then subjected to a blanking operation, wherein the blanking operation is performed by die cutting and slitting, by using a specific tool and a specific device, the continuous negative electrode tape is cut into single negative electrode pieces with negative electrode tabs.
Example 1
S1: providing a rolled negative electrode roll, and carrying out feeding operation on the negative electrode roll in a coating machine, wherein the thickness of a negative electrode sheet is 110 mu m, and the thickness of a single-side coating is 50 mu m;
s2: unreeling the negative electrode coil, enabling a negative electrode belt to enter an oven, wherein the oven is provided with a roller, a contact position of the roller and an electrode lug area is provided with an electrode lug cushion high ring, the electrode lug cushion high ring is obtained by winding a Teflon adhesive tape around the roller, the height of the electrode lug cushion high ring is 40 mu m and is 1mm away from a coating area, the balance degree of the roller is adjusted before unreeling operation, the air outlet direction of an air nozzle of the oven is adjusted, and an air port is prevented from directly blowing the electrode lug area;
s3: the length of the oven is 40m, the temperature of the oven is adjusted to be 100 ℃, the speed of the belt is controlled to be 10m/min, and the negative pole belt is baked.
S4: and (4) carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain a plurality of single negative electrode plates.
Example 2
S1: providing a rolled negative electrode roll, and carrying out loading operation on the negative electrode roll in a coating machine, wherein the thickness of a negative electrode sheet is 110 mu m, and the thickness of a single-side coating is 50 mu m;
s2: unreeling the negative electrode coil, enabling a negative electrode belt to enter an oven, wherein the oven is provided with a roller, a contact position of the roller and an electrode lug area is provided with an electrode lug cushion high ring, the electrode lug cushion high ring is obtained by winding a Teflon adhesive tape around the roller, the height of the electrode lug cushion high ring is 45 mu m and is 0.5mm away from a coating area, the balance degree of the roller is adjusted before unreeling, the air outlet direction of an air nozzle of the oven is adjusted, and the air port is prevented from directly blowing the electrode lug area;
s3: the length of the oven is 40m, the temperature of the oven is adjusted to be 110 ℃, the speed of the belt is controlled to be 20m/min, and the negative pole belt is baked.
S4: and (4) carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain a plurality of single negative electrode plates.
Example 3
S1: providing a rolled negative electrode roll, and carrying out loading operation on the negative electrode roll in a coating machine, wherein the thickness of a negative electrode sheet is 110 mu m, and the thickness of a single-side coating is 50 mu m;
s2: unreeling the negative pole coil, enabling the negative pole belt to enter an oven, wherein the oven is provided with a roller, a pole lug cushion high ring is arranged at the contact position of the roller and a pole lug area, the pole lug cushion high ring is obtained by winding a Teflon adhesive tape around the roller, the height of the pole lug cushion high ring is 48 mu m and is 2mm away from a coating area, the balance degree of the roller is adjusted before unreeling, the air outlet direction of an air nozzle of the oven is adjusted, and an air port is prevented from directly blowing the pole lug area;
s3: the length of the oven is 40m, the temperature of the oven is adjusted to 90 ℃, the speed of the belt is controlled to be 8m/min, and the negative pole belt is baked.
S4: and (4) carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain a plurality of single negative electrode plates.
Comparative example 1
And (3) providing rolled negative electrode rolls with the same winding number as that of the negative electrode roll in example 1, wherein the thickness of the negative electrode sheet is 110 microns, the thickness of the coating on one side is 50 microns, transporting the negative electrode rolls to a high-temperature baking room for baking, wherein the baking temperature is 100 ℃, the baking time is 4min, and performing die cutting and slitting operation after baking to obtain a plurality of single negative electrode sheets.
Comparative example 2
Comparative example 2 is different from example 1 in that the roll passing in step S2 is not provided with an ear pad high ring.
Comparative example 3
Comparative example 3 is different from example 1 in that the height of the upper ring of the auricle pad in the step S2 is 50 μm.
Comparative example 4
Comparative example 4 is different from example 1 in that the oven temperature in the step S3 is 80 ℃ and the traveling speed is 50m/min.
200 single negative plates were randomly selected from examples 1 to 3 and comparative examples 1 to 4, respectively, and subjected to tab appearance inspection and thickness measurement, and the specific results are shown in table 1.
And detecting the appearance of the lug: and observing whether the tab of the negative plate has the phenomena of wrinkling, folding, breakage and deformation by naked eyes, and if the tab of the negative plate has the phenomena, determining that the tab is poor.
And (3) thickness measurement: and (3) performing coating area thickness test on the negative plates by using a thickness detection device, and calculating the average thickness value and standard deviation of 200 negative plates.
Table 1 thickness of negative electrode sheet and number of defective tabs (n = 200) of examples and comparative examples
Figure BDA0003773579300000071
Figure BDA0003773579300000081
The rebound rate of the negative electrode sheet = (the thickness of the negative electrode sheet after baking-the thickness of the non-baked negative electrode sheet-the thickness of the current collector)/the thickness of the non-baked negative electrode sheet, and the thickness of the current collector in the embodiment is 10 μm.
As can be seen from the data in table 1, after the cathode plate baking process of the present invention, the cathode plate rebound rate of examples 1 to 3 can reach more than 14%, and the thickness uniformity of the cathode plate can be controlled within ± 2.5 μm, and meanwhile, the amount of defective tabs can be maintained within a certain range by adjusting the structure of the roller during the baking process.
The comparative example 1 is a traditional negative electrode coil baking process, and data show that the average thickness of the negative electrode sheet of the comparative example 1 is obviously reduced compared with that of the example 1, the thickness rebound rate is 8.9%, and the standard deviation of the thickness is +/-8.8 microns, obviously, after the baking process provided by the invention is adopted, the thickness consistency of the negative electrode sheet is obviously improved, the single-layer negative electrode belt is baked by the invention, the heating is more sufficient and uniform, and the thickness rebound rate of the negative electrode sheet finally prepared by the invention is improved under the same baking condition; furthermore, as can be seen from the defective number of the tabs, the defective number of the tabs is not obviously improved compared with the conventional baking process after the process adjustment such as the adjustment of the roller-passing balance degree, the arrangement of the high ring of the tab cushion, the change of the wind direction of the air nozzle and the like.
The roller of the comparative example 2 is not provided with the lug high ring, the defective number of the lugs is obviously increased, which shows that the lug high ring can reduce the height difference between a coating area and a lug area in the process of taking the negative pole away from the belt, and can ensure that the lug area is smooth and has no crumpling phenomenon, so that the defective number of the lugs is obviously reduced; meanwhile, the data of the comparative example 3 show that when the thickness of the high ring of the pole lug pad is equal to the thickness of the single-side coating of the negative pole piece and the thickness difference is not reserved, the tension is too large when the pole lug area passes through a roller, so that the pole lug is broken, and the final bad number of the pole lug is increased.
The oven of comparative example 4 sets a lower baking temperature and a higher tape running speed, which results in a poor thickness rebound rate of the finally prepared negative electrode sheet, and shows that in the baking process of the negative electrode sheet, the parameters of the oven need to be adjusted according to the negative electrode sheet so as to sufficiently bake the negative electrode sheet and achieve the best thickness rebound rate.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The negative plate baking process is characterized by comprising the following steps of:
s1: providing a rolled negative electrode coil, and carrying out feeding operation on the negative electrode coil in a coating machine;
s2: unreeling the negative electrode coil to enable the negative electrode belt to enter an oven;
s3: adjusting the temperature and the tape-moving speed of the oven, and baking the negative tape;
s4: and carrying out blanking, die cutting and slitting operations on the baked negative electrode strip to obtain the negative electrode plate.
2. The negative plate baking process of claim 1, wherein the oven is provided with a roller, the negative strip is in contact with the roller, and the roller is subjected to balance adjustment before the baking operation.
3. The negative plate baking process according to claim 2, wherein the negative plate comprises a coating area and a tab area located at one end of the coating area, and a tab high ring is arranged on the roller at a position where the roller contacts the tab area.
4. The negative plate baking process according to claim 3, wherein the thickness of the high ring of the tab pad is 5-10 μm smaller than the thickness of the single-side coating of the negative strip.
5. The negative plate baking process of claim 3, wherein the high tab ring is disposed at a distance of 0.5-2.0 mm from the coating region.
6. The negative plate baking process of claim 3, wherein the high ring of the polar ear pads is obtained by winding smooth soft adhesive tapes around the roller.
7. The negative plate baking process according to claim 1, wherein the oven temperature is 90-110 ℃.
8. The negative plate baking process according to claim 1, wherein the oven length is 35-150 m, and the tape transport speed is 5-25 m/min.
9. A negative electrode plate, characterized by being prepared by the negative electrode plate baking process according to any one of claims 1 to 8.
10. A lithium battery comprising the negative electrode sheet of claim 9.
CN202210912181.XA 2022-07-29 2022-07-29 Negative plate baking process, negative plate and lithium battery Pending CN115275112A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101877397A (en) * 2009-06-24 2010-11-03 宁波维科电池有限公司 Continuous rolling process for lithium-ion battery electrode and device thereof
CN206163605U (en) * 2016-11-07 2017-05-10 宁德时代新能源科技股份有限公司 Pole piece drying device that colds pressing
CN206619646U (en) * 2017-03-08 2017-11-07 东莞塔菲尔新能源科技有限公司 A kind of pole piece drying forming machine
CN211247949U (en) * 2019-08-30 2020-08-14 蜂巢能源科技有限公司 Pole piece rolling device of lithium battery

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101877397A (en) * 2009-06-24 2010-11-03 宁波维科电池有限公司 Continuous rolling process for lithium-ion battery electrode and device thereof
CN206163605U (en) * 2016-11-07 2017-05-10 宁德时代新能源科技股份有限公司 Pole piece drying device that colds pressing
CN206619646U (en) * 2017-03-08 2017-11-07 东莞塔菲尔新能源科技有限公司 A kind of pole piece drying forming machine
CN211247949U (en) * 2019-08-30 2020-08-14 蜂巢能源科技有限公司 Pole piece rolling device of lithium battery

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