CN111486664A - Baking curve construction method and baking method of lithium ion battery pole piece - Google Patents
Baking curve construction method and baking method of lithium ion battery pole piece Download PDFInfo
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- CN111486664A CN111486664A CN202010327167.4A CN202010327167A CN111486664A CN 111486664 A CN111486664 A CN 111486664A CN 202010327167 A CN202010327167 A CN 202010327167A CN 111486664 A CN111486664 A CN 111486664A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/22—Controlling the drying process in dependence on liquid content of solid materials or objects
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
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Abstract
The invention belongs to the technical field of processing and manufacturing of lithium ion batteries, particularly relates to a baking curve construction method based on lithium ion battery pole pieces made of different materials, and further discloses a baking method of the lithium ion battery pole pieces. According to the baking curve construction method and the baking method of the lithium ion battery pole piece, firstly, baking pressure change rate curves of different material systems are obtained through one-time experiment and data analysis, the water removal rate in the baking process is represented through the pressure change rate, the appropriate pressure change rate is selected as the baking finish condition, the vacuum baking time is correspondingly and automatically adjusted, the baking condition of the pole piece of a new material system can be rapidly determined, the method can be used for one-time effective baking of the pole piece under different initial water containing conditions, and the baking efficiency is effectively improved.
Description
Technical Field
The invention belongs to the technical field of processing and manufacturing of lithium ion batteries, particularly relates to a baking curve construction method based on lithium ion battery pole pieces made of different materials, and further discloses a baking method of the lithium ion battery pole pieces.
Background
In the processing and manufacturing process of the lithium ion battery, because moisture can cause adverse effects on the performances of the battery such as gas production, capacity, internal resistance, circulation and the like, moisture in the pole piece needs to be removed through a baking process so as to ensure that the moisture content in the battery is lower than a certain standard, and further ensure the service performance of the battery.
In the prior art, a dewatering method for a lithium ion battery pole piece generally comprises the steps of placing the lithium ion battery pole piece in a vacuum oven for baking, baking and dewatering the pole piece by setting certain temperature, vacuum degree and time, and testing the moisture of the pole piece after baking is finished to judge whether the pole piece is qualified. The baking process of the conventional battery pole piece in the prior art comprises the following steps: 1. putting a certain number of pole pieces into a vacuum oven, vacuumizing and filling nitrogen; 2. preheating: heating by using the set temperature and time; 3. and (3) vacuum drying: performing nitrogen pressure maintaining, vacuum drying and breathing type circulation for a set time; 4. cooling: after the water removal is finished, cooling the temperature to a set temperature by using cooling nitrogen in a circulating manner; 5. taking out the baked pole piece, and carrying out moisture test; 6. if the moisture test result is qualified, transferring to the next procedure; and if the moisture test fails, repeating the baking and testing processes.
Although the conventional vacuum baking process can solve the problem of water removal of most lithium ion battery pole pieces, the initial moisture content of the pole pieces in the same system and different batches is different before baking, and the conventional baking mode is difficult to ensure that the moisture of the pole pieces with high initial moisture content is qualified after baking. Usually, the moisture content test is required after the baking is finished, and the baking is required to be carried out again if the judgment is unqualified, so that the production efficiency is seriously influenced.
More importantly, when the battery pole piece of a new material system is replaced for baking, the optimal baking time of the new system is difficult to directly select, and only multiple repeated tests can be carried out by setting different baking conditions, so that the better baking condition can be determined by multiple test results; moreover, when the baking condition is used for practical application, the problem that the batch of the pole pieces with high initial moisture content is unqualified to be baked again still exists.
Therefore, the development of the baking method based on different materials of the lithium ion battery pole piece, which can quickly determine the optimal baking condition and meet the baking performance requirements of the battery pole piece with different initial moisture contents, has positive significance for the processing of the lithium ion battery.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to provide a baking curve construction method of a lithium ion battery pole piece, so as to obtain the optimal baking condition of the battery pole piece based on different materials and different initial moisture conditions;
the second technical problem to be solved by the invention is to provide a baking method of a lithium ion battery pole piece, which can ensure that the baking moisture of the pole piece is qualified at one time without repeated baking when the method is applied to baking pole pieces with different batches and different initial moisture contents; when the method is applied to the baking of a new material system, the baking conditions of the pole piece of the new material system can be quickly optimized and determined.
In order to solve the technical problem, the baking curve construction method of the lithium ion battery pole piece comprises the following steps:
(1) taking a battery pole piece sample of a selected material, and measuring the initial moisture content of the battery pole piece sample, wherein the initial moisture content is marked as A0; taking the battery pole pieces which are in the same batch and under the same storage condition as the sample, and loading the battery pole pieces into vacuum baking equipment according to the preset baking quantity; then vacuumizing the high-vacuum oven, filling nitrogen, and heating and preheating to a set baking temperature;
(2) after the battery pole piece is preheated to the set baking temperature, preserving heat and vacuumizing to the set initial pressure, dewatering the battery pole piece, detecting the pressure of a system to rise to the set cut-off pressure, vacuumizing again to the initial pressure, repeating the pressure control process until the moisture content of the battery pole piece is predicted to meet the preset standard value, and recording the time of the system pressure value rising from the initial pressure to the cut-off pressure value every time, wherein the time is recorded as T1, T2 and T3 … … Tn in sequence;
(3) after the vacuum drying is finished, vacuumizing again to the initial pressure value, cooling under the protection of nitrogen, taking out the battery pole piece, testing the cut-off moisture content of the pole piece and recording as A1, and performing data analysis and baking curve construction;
(4) taking vacuum drying section data, wherein when vacuum drying starts, the drying pressure is an initial pressure value, the moisture corresponding to the battery pole piece is an initial moisture value A0, the drying pressure is a cut-off pressure value, the moisture corresponding to the battery pole piece is a cut-off moisture value A1, in the interval range, according to the standard that the moisture content of the battery pole piece is uniformly reduced once in each period that the system pressure is increased from the initial pressure value to the cut-off pressure value, the difference value (A0-A1)/n of the moisture content of the battery pole piece in each period is estimated, and the moisture content value of the battery pole piece is calculated when the system pressure value reaches the set cut-off pressure value in each period and is respectively marked as a1, a2 and A3 … …;
(5) constructing and obtaining a required baking curve by taking the recorded vacuum drying time as an abscissa and respectively taking the corresponding pressure value and the corresponding estimated moisture content value as an ordinate; and reading a pressure change cycle time value Tn corresponding to the situation that the moisture content value of the battery pole piece in the baking curve reaches a set baking standard value, and selecting the pressure change cycle time value T which is more than or equal to Tn in the baking process as a process cut-off condition of the actual vacuum baking process.
Specifically, in the step (2), the initial pressure value P1 is controlled to be 0-100Pa, the cut-off pressure value P2 is controlled to be 50-400Pa, and P2 is greater than P1.
Specifically, the baking temperature of the present invention is controlled to any temperature that does not cause material degradation, and it is preferable to control the baking temperature to 90 to 150 ℃.
Specifically, the step (2) further comprises the step of controlling the vacuum baking equipment to automatically record the temperature and the vacuum degree in the baking oven cavity every minute in the baking process.
Specifically, in the step (3), the temperature is reduced to below 45 ℃.
Specifically, the lithium ion battery pole piece comprises a positive pole piece and a negative pole piece of the lithium ion battery which take materials such as lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobaltate, lithium manganate, lithium titanate, graphite, silicon carbon and the like as main materials.
The invention also discloses application of the baking curve construction method of the lithium ion battery pole piece in a baking process of the lithium ion battery pole piece.
The invention also discloses a baking process of the lithium ion battery pole piece, which comprises the following steps:
(a) constructing a baking curve of the battery pole piece made of the selected material according to the method, and reading a pressure change cycle time value T which is more than or equal to Tn in the baking process as a process cut-off condition of the actual vacuum baking process;
(b) placing battery pole pieces made of the same material in the vacuum baking equipment, vacuumizing and filling nitrogen, and heating and preheating to a set baking temperature;
(c) after the battery pole piece is preheated to the set baking temperature, preserving heat and vacuumizing to the set initial pressure, dewatering the battery pole piece, detecting the system pressure to rise to the set cut-off pressure, vacuumizing again to the initial pressure, repeating the pressure control process, recording the time T of the system pressure value rising from the initial pressure to the cut-off pressure value each time, and when the T is larger than or equal to Tn, finishing the vacuum drying process and cooling under the protection of nitrogen, thus obtaining the battery pole piece.
Specifically, the initial pressure value P1 is controlled to be 0-100Pa, the cut-off pressure value P2 is controlled to be 50-400Pa, and the baking temperature is controlled to be 90-150 ℃.
Specifically, the baking process of the lithium ion battery pole piece further comprises the step of testing the moisture content of the battery pole piece after baking is finished.
According to the method for constructing the baking curve of the lithium ion battery pole piece, the baking pressure change rate curves of different material systems are obtained through one-time experiment and data analysis, the water removal rate in the baking process is represented through the pressure change rate, the proper pressure change rate is selected as the baking finish condition, the vacuum baking time is correspondingly and automatically adjusted, the baking condition of the pole piece of a new material system can be rapidly determined, the method can be used for one-time effective baking of the pole piece under different initial water containing conditions, and the baking efficiency is effectively improved. According to the scheme, the baking is finished when the set baking cut-off condition is reached, the baking time reaching the cut-off condition is different due to different initial water contents, and the baking time is automatically adjusted through the cut-off condition. Compared with the prior art, the operation mode that the drying of the pole piece is qualified is ensured by setting the baking time which is long enough as the baking finish condition, so that the baking time and the energy consumption are effectively saved.
The baking method of the lithium ion battery pole piece determines the optimized baking finish condition based on the baking curve, applies the optimized baking stop condition to the baking of the pole pieces with the same material system and different initial moisture contents, and can ensure that the moisture contents of the pole pieces with different initial moisture contents are controlled within a target range without baking again when the pressure change rate levels are consistent under the same condition (same material system and same baking quantity), so that the baking efficiency is improved.
The baking method of the lithium ion battery pole piece can be realized in a nitrogen pressure maintaining-vacuum drying breathing type circulating drying mode on the basis of ensuring the vacuum time, and the baking effect and the pole piece performance are more effectively ensured.
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In order that the present disclosure may be more readily and clearly understood, the following detailed description of the present disclosure is provided in connection with specific embodiments thereof and the accompanying drawings, in which,
fig. 1 is a baking curve of the lithium ion battery pole piece constructed in example 1.
Fig. 2 is a baking curve of the lithium ion battery pole piece constructed in example 2.
Detailed Description
Example 1
The embodiment is directed at baking a lithium ion battery pole piece made of a graphite negative electrode material.
Sampling a negative pole piece to be baked, wherein the size of the sample has no influence, and testing the initial moisture content of the pole piece before baking by using a Karl Fischer moisture tester, wherein the initial moisture content is recorded as A0-838 ppm; and taking the pole pieces stored in the same batch and under the same storage condition as the sampling pole pieces, and loading the pole pieces into a high-vacuum oven according to the preset baking quantity of 27000 for later use. In this embodiment, the setting conditions for baking the pole pieces with different initial water contents are completely the same, and the conditions of temperature, pressure and quantity are kept completely consistent when the initial curve is constructed, so that the pole pieces can be used as the cut-off conditions for the subsequent baking process, and the curve construction stage has no special requirements for the initial water content and only needs to be tested to be used as the calculation conditions.
Vacuumizing a drying cavity of the oven to less than or equal to 200Pa, filling nitrogen, and preheating for 3 hours at the preheating temperature of 130 ℃ under the protection of the nitrogen, so that all the pole pieces in the drying cavity reach the drying temperature of 130 ℃.
Further vacuumizing the drying cavity under the condition of heat preservation at 130 ℃ until the initial pressure value is 50Pa, dewatering the pole piece at the moment, gradually increasing the pressure in the drying cavity to 200Pa, and recording the time of increasing the pressure from 50Pa to 200Pa in the process, namely a pressure change period which is recorded as T1; then immediately vacuumizing until the system pressure value is reduced to 50Pa, then gradually increasing the system pressure in the drying cavity to 200Pa along with drying and dewatering of the pole piece, and recording the time of the pressure change period as T2; repeating the pressure control variation process until the moisture content value of the battery pole piece is estimated to be lower than a standard value (the moisture content is less than or equal to 250 ppm); after the pole piece passes through the 6 pressure change cycles, the moisture content of the pole piece is predicted to reach the baking standard value, the time of each pressure change cycle is recorded, and the time is T1-5 min, T2-7 min, T3-11 min, T4-30 min, T5-85 min, and T6-128 min, so that the drying process is ended.
After the vacuum drying is finished, vacuumizing to control the pressure value to be 50Pa, filling nitrogen, and cooling to below 45 ℃ in a nitrogen protection descending system; and after the temperature reduction is finished, taking out the battery pole piece, testing the moisture content A1 of the pole piece to be 200ppm, and carrying out subsequent data analysis and curve construction according to the moisture content of the pole piece which is below a target value.
Estimating a moisture value: according to the vacuum drying section data, when the vacuum drying is started, namely the system pressure is 50Pa, the corresponding pole piece moisture is initial moisture A0 before baking which is 838ppm, the moisture content is calculated according to the uniform and degressive calculation of the moisture content in a pressure change period of increasing the pressure from 50Pa to 200Pa, and the moisture content change value in each pressure change interval in the whole drying interval is (838-
And calculating 106.33, when the system pressure value reaches 200Pa in each pressure change interval, estimating the moisture values of the corresponding battery pole pieces as a 1-731.7 ppm, a 2-625.3 ppm, a 3-519 ppm, A4-412.6 ppm and a 5-306.3 ppm respectively, and calculating the moisture value of the corresponding pole piece as the moisture of the pole piece after baking A1-200 ppm when the vacuum drying is finished.
The vacuum drying time in the whole drying process is taken as an abscissa, the corresponding pressure value and the corresponding estimated moisture value are taken as ordinates respectively to carry out baking curve plotting, and the baking curve of the material system pole piece is drawn and obtained as shown in figure 1.
According to the baking curve, because the moisture content of the pole piece is qualified when the moisture content of the pole piece is less than or equal to 250ppm according to the pole piece baking standard, in the baking curve of the embodiment, the time T6 of the pressure change period corresponding to the first point 200ppm at which the moisture content of the pole piece reaches the standard is 128min, and therefore, the time T of the pressure change period is selected as the cut-off condition of the subsequent vacuum baking process when the time T of the pressure change period is more than or equal to 128 min.
And putting the battery pole pieces with the same quantity and different moisture contents and the same material system into the high-vacuum oven for vacuum drying.
Vacuumizing a drying cavity of the oven to less than or equal to 200Pa, filling nitrogen, and preheating for 3 hours at the preheating temperature of 130 ℃ under the protection of the nitrogen, so that all the pole pieces in the drying cavity reach the drying temperature of 130 ℃.
Further vacuumizing the drying cavity under the condition of heat preservation at 130 ℃ until the initial pressure value is 50Pa, dewatering the pole piece at the moment, gradually increasing the pressure in the drying cavity to 200Pa, and recording the time of increasing the pressure from 50Pa to 200Pa in the process, namely a pressure change period which is recorded as T1; then immediately vacuumizing until the system pressure value is reduced to 50Pa, then gradually increasing the system pressure in the drying cavity to 200Pa along with drying and dewatering of the pole piece, and recording the time of the pressure change period as T2; repeating the pressure control change process until the detected pressure change period T is more than or equal to 128min, stopping vacuum drying, introducing nitrogen, and cooling to below 45 ℃ under the protection of nitrogen; after the temperature reduction is finished, the pole pieces are taken out to test the moisture content of each pole piece, the moisture content of all the pole pieces baked in the embodiment is less than or equal to 250ppm, and the baking is qualified.
Therefore, the baking method of the lithium ion battery pole piece can meet the baking requirements of battery pole pieces made of different materials, can realize one-time baking of pole pieces with different initial moisture contents to reach the standard, and can completely meet the baking process requirements of the battery pole pieces.
Example 2
The embodiment is directed at baking the lithium ion battery pole piece made of the nickel-cobalt-manganese ternary material.
Sampling a positive pole piece to be baked, and testing the initial moisture content of the pole piece before baking by using a Karl Fischer moisture tester, wherein the initial moisture content is recorded as A0-440 ppm; and taking the pole pieces stored in the same batch and under the same storage condition as the sampling pole pieces, and loading the pole pieces into a high-vacuum oven according to the preset baking quantity of 27000 for later use.
Vacuumizing a drying cavity of the oven to less than or equal to 200Pa, filling nitrogen, and preheating for 5 hours at the preheating temperature of 130 ℃ under the protection of the nitrogen, so that all the pole pieces in the drying cavity reach the drying temperature of 130 ℃.
Further vacuumizing the drying cavity under the condition of heat preservation at 130 ℃ until the initial pressure value is 50Pa, dewatering the pole piece at the moment, gradually increasing the pressure in the drying cavity to 200Pa, and recording the time of increasing the pressure from 50Pa to 200Pa in the process, namely a pressure change period which is recorded as T1; then immediately vacuumizing until the system pressure value is reduced to 50Pa, then gradually increasing the system pressure in the drying cavity to 200Pa along with drying and dewatering of the pole piece, and recording the time of the pressure change period as T2; repeating the pressure control variation process until the moisture content value of the battery pole piece is estimated to be lower than a standard value (the moisture content is less than or equal to 150 ppm); after the pole piece passes through the 8 pressure change cycles, the moisture content of the pole piece is predicted to reach the baking standard value, the time of each pressure change cycle is recorded, wherein the time is T1-4 min, T2-5 min, T3-7 min, T4-10 min, T5-13 min, T6-30 min, T7-35 min, and T8-48 min, and the drying process is ended.
After the vacuum drying is finished, vacuumizing to control the pressure value to be 50Pa, filling nitrogen, and cooling to below 45 ℃ in a nitrogen protection descending system; and after the temperature reduction is finished, taking out the battery pole piece, testing the moisture content A1 of the pole piece to be 55ppm, and carrying out subsequent data analysis and curve construction according to the moisture content of the pole piece which is below a target value.
Estimating a moisture value: according to the vacuum drying section data, when the vacuum drying is started, namely the system pressure is 50Pa, the moisture of the corresponding pole piece is initial moisture A0 which is 440ppm before baking, the moisture content is uniformly decreased once in a pressure change period of increasing the pressure from 50Pa to 200Pa, the moisture content change value in each pressure change interval is (440-55)/8 which is 48.1 in the whole drying interval, and therefore, in each pressure change interval, when the system pressure value reaches 200Pa, the moisture values of the corresponding battery pole piece are respectively estimated to be a1 which is 391.9ppm, a2 which is 343.8ppm, A3 which is 295.6ppm, a4 which is 247.5ppm, a5 which is 199.4ppm, a6 which is 151.2ppm, a7 which is 103.1ppm, and when the vacuum drying is finished, the moisture of the corresponding pole piece is baked pole piece A1 which is 55.0 ppm.
The vacuum drying time in the whole drying process is taken as an abscissa, the corresponding pressure value and the corresponding estimated moisture value are taken as ordinates respectively to carry out baking curve plotting, and the baking curve of the material system pole piece is drawn and obtained as shown in figure 2.
According to the baking curve, because the moisture content of the pole piece is qualified when the moisture content of the pole piece is less than or equal to 130ppm according to the pole piece baking standard, in the baking curve of the embodiment, the time T7 of the pressure change period corresponding to the first point 103.1ppm that the moisture content of the pole piece reaches the standard is 35min, and therefore, the time T of the pressure change period is selected as the cut-off condition of the subsequent vacuum baking process when the time T of the pressure change period is greater than or equal to 35 min.
And putting the battery pole pieces with the same quantity and different moisture contents and the same material system into the high-vacuum oven for vacuum drying.
Vacuumizing a drying cavity of the oven to less than or equal to 200Pa, filling nitrogen, and preheating for 5 hours at the preheating temperature of 130 ℃ under the protection of the nitrogen, so that all the pole pieces in the drying cavity reach the drying temperature of 130 ℃.
Further vacuumizing the drying cavity under the condition of heat preservation at 130 ℃ until the initial pressure value is 50Pa, dewatering the pole piece at the moment, gradually increasing the pressure in the drying cavity to 200Pa, and recording the time of increasing the pressure from 50Pa to 200Pa in the process, namely a pressure change period which is recorded as T1; then immediately vacuumizing until the system pressure value is reduced to 50Pa, then gradually increasing the system pressure in the drying cavity to 200Pa along with drying and dewatering of the pole piece, and recording the time of the pressure change period as T2; repeating the pressure control change process until the detected pressure change period T is more than or equal to 35min, stopping vacuum drying, introducing nitrogen, and cooling to below 45 ℃ under the protection of nitrogen; after the temperature reduction is finished, the pole pieces are taken out to test the moisture content of each pole piece, the moisture content of all the pole pieces baked in the embodiment is less than or equal to 130ppm, and the baking is qualified.
Therefore, the baking method of the lithium ion battery pole piece can meet the baking requirements of battery pole pieces made of different materials, can realize one-time baking of pole pieces with different initial moisture contents to reach the standard, and can completely meet the baking process requirements of the battery pole pieces.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (10)
1. A baking curve construction method of a lithium ion battery pole piece is characterized by comprising the following steps:
(1) taking a battery pole piece sample of a selected material, and measuring the initial moisture content of the battery pole piece sample, wherein the initial moisture content is marked as A0; taking the battery pole pieces which are in the same batch and under the same storage condition as the sample, and loading the battery pole pieces into vacuum baking equipment according to the preset baking quantity; then vacuumizing the high-vacuum oven, filling nitrogen, and heating and preheating to a set baking temperature;
(2) after the battery pole piece is preheated to the set baking temperature, preserving heat and vacuumizing to the set initial pressure, dewatering the battery pole piece, detecting the pressure of a system to rise to the set cut-off pressure, vacuumizing again to the initial pressure, repeating the pressure control process until the moisture content of the battery pole piece is predicted to meet the preset standard value, and recording the time of the system pressure value rising from the initial pressure to the cut-off pressure value every time, wherein the time is recorded as T1, T2 and T3 … … Tn in sequence;
(3) after the vacuum drying is finished, vacuumizing again to the initial pressure value, cooling under the protection of nitrogen, taking out the battery pole piece, testing the cut-off moisture content of the pole piece and recording as A1, and performing data analysis and baking curve construction;
(4) taking vacuum drying section data, wherein when vacuum drying starts, the drying pressure is an initial pressure value, the moisture corresponding to the battery pole piece is an initial moisture value A0, the drying pressure is a cut-off pressure value, the moisture corresponding to the battery pole piece is a cut-off moisture value A1, in the interval range, according to the standard that the moisture content of the battery pole piece is uniformly reduced once in each period that the system pressure is increased from the initial pressure value to the cut-off pressure value, the difference value (A0-A1)/n of the moisture content of the battery pole piece in each period is estimated, and the moisture content value of the battery pole piece is calculated when the system pressure value reaches the set cut-off pressure value in each period and is respectively marked as a1, a2 and A3 … …;
(5) constructing and obtaining a required baking curve by taking the recorded vacuum drying time as an abscissa and respectively taking the corresponding pressure value and the corresponding estimated moisture content value as an ordinate; and reading a pressure change cycle time value Tn corresponding to the situation that the moisture content value of the battery pole piece in the baking curve reaches a set baking standard value, and selecting the pressure change cycle time value T which is more than or equal to Tn in the baking process as a process cut-off condition of the actual vacuum baking process.
2. The method for constructing the baking curve of the lithium ion battery pole piece according to claim 1, wherein in the step (2), the initial pressure value P1 is controlled to be 0-100Pa, the cut-off pressure value P2 is controlled to be 50-400Pa, and P2 is greater than P1.
3. The method for constructing the baking curve of the lithium ion battery pole piece according to claim 1 or 2, wherein the baking temperature is controlled to be 90-150 ℃.
4. The method for constructing the baking curve of the lithium ion battery pole piece according to any one of claims 1 to 3, wherein the step (2) further comprises the step of controlling the vacuum baking equipment to automatically record the temperature and the vacuum degree in the cavity of the oven every minute in the baking process.
5. The method for constructing the baking curve of the lithium ion battery pole piece according to any one of claims 1 to 4, wherein in the step (3), the temperature is reduced to below 45 ℃.
6. The method for constructing the baking curve of the lithium ion battery pole piece according to any one of claims 1 to 5, wherein the lithium ion battery pole piece comprises a positive pole piece and a negative pole piece of a lithium ion battery which take lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobalt oxide, lithium manganese oxide, lithium titanate, graphite, silicon carbon and other materials as main materials.
7. The application of the method for constructing the baking curve of the lithium ion battery pole piece in any one of claims 1 to 6 in the baking process of the lithium ion battery pole piece.
8. A lithium ion battery pole piece baking process is characterized by comprising the following steps:
(a) constructing a baking curve of the battery pole piece made of the selected material according to the method of any one of claims 1 to 6, and reading a pressure change cycle time value T which is more than or equal to Tn in the baking process as a process cut-off condition of an actual vacuum baking process;
(b) placing battery pole pieces made of the same material in the vacuum baking equipment, vacuumizing and filling nitrogen, and heating and preheating to a set baking temperature;
(c) after the battery pole piece is preheated to the set baking temperature, preserving heat and vacuumizing to the set initial pressure, dewatering the battery pole piece, detecting the system pressure to rise to the set cut-off pressure, vacuumizing again to the initial pressure, repeating the pressure control process, recording the time T of the system pressure value rising from the initial pressure to the cut-off pressure value each time, and when the T is larger than or equal to Tn, finishing the vacuum drying process and cooling under the protection of nitrogen, thus obtaining the battery pole piece.
9. The lithium ion battery pole piece baking process of claim 8, wherein the initial pressure value P1 is controlled to be 0-100Pa, the cut-off pressure value P2 is controlled to be 50-400Pa, and the baking temperature is controlled to be 90-150 ℃.
10. The baking process of the lithium ion battery pole piece according to claim 8 or 9, further comprising the step of testing the moisture content of the battery pole piece after baking is finished.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010327167.4A CN111486664B (en) | 2020-04-23 | 2020-04-23 | Baking curve construction method and baking method of lithium ion battery pole piece |
Applications Claiming Priority (1)
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113358824A (en) * | 2021-06-02 | 2021-09-07 | 合肥国轩高科动力能源有限公司 | Online moisture detection method in vacuum drying process of battery |
| CN114659341A (en) * | 2022-03-02 | 2022-06-24 | 上海兰钧新能源科技有限公司 | Control method for baking lithium ion battery |
| CN117932975A (en) * | 2024-03-20 | 2024-04-26 | 宁德时代新能源科技股份有限公司 | Method and device for predicting dry state of electrode plate |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20120052650A (en) * | 2010-11-16 | 2012-05-24 | 삼성에스디아이 주식회사 | Apparatus and method for drying electrode plate |
| CN105115250A (en) * | 2015-07-27 | 2015-12-02 | 山东精工电子科技有限公司 | Rapid drying method for lithium ion battery cell |
| CN205264794U (en) * | 2015-11-30 | 2016-05-25 | 金川集团股份有限公司 | Dry turnover device of lithium ion power batteries pole piece |
| CN207317486U (en) * | 2017-09-13 | 2018-05-04 | 河北银隆新能源有限公司 | A kind of apparatus for baking of electrodes of lithium-ion batteries |
| CN207778955U (en) * | 2017-12-26 | 2018-08-28 | 宜昌三峡普诺丁生物制药有限公司 | A kind of swinging vacuum drying bipyramid equipment |
| CN208012313U (en) * | 2018-02-07 | 2018-10-26 | 来莎来酷（福建）服饰实业有限公司 | A kind of cloth drying device for producing underpants |
-
2020
- 2020-04-23 CN CN202010327167.4A patent/CN111486664B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20120052650A (en) * | 2010-11-16 | 2012-05-24 | 삼성에스디아이 주식회사 | Apparatus and method for drying electrode plate |
| CN105115250A (en) * | 2015-07-27 | 2015-12-02 | 山东精工电子科技有限公司 | Rapid drying method for lithium ion battery cell |
| CN205264794U (en) * | 2015-11-30 | 2016-05-25 | 金川集团股份有限公司 | Dry turnover device of lithium ion power batteries pole piece |
| CN207317486U (en) * | 2017-09-13 | 2018-05-04 | 河北银隆新能源有限公司 | A kind of apparatus for baking of electrodes of lithium-ion batteries |
| CN207778955U (en) * | 2017-12-26 | 2018-08-28 | 宜昌三峡普诺丁生物制药有限公司 | A kind of swinging vacuum drying bipyramid equipment |
| CN208012313U (en) * | 2018-02-07 | 2018-10-26 | 来莎来酷（福建）服饰实业有限公司 | A kind of cloth drying device for producing underpants |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113358824A (en) * | 2021-06-02 | 2021-09-07 | 合肥国轩高科动力能源有限公司 | Online moisture detection method in vacuum drying process of battery |
| CN114659341A (en) * | 2022-03-02 | 2022-06-24 | 上海兰钧新能源科技有限公司 | Control method for baking lithium ion battery |
| CN117932975A (en) * | 2024-03-20 | 2024-04-26 | 宁德时代新能源科技股份有限公司 | Method and device for predicting dry state of electrode plate |
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