CN113358824A - Online moisture detection method in vacuum drying process of battery - Google Patents
Online moisture detection method in vacuum drying process of battery Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 75
- 230000008569 process Effects 0.000 title claims abstract description 57
- 238000001291 vacuum drying Methods 0.000 title claims abstract description 45
- 238000001514 detection method Methods 0.000 title claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 45
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 10
- 239000007789 gas Substances 0.000 claims description 9
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- 238000001035 drying Methods 0.000 abstract description 15
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 239000003990 capacitor Substances 0.000 abstract description 2
- 238000001704 evaporation Methods 0.000 description 6
- 230000008020 evaporation Effects 0.000 description 6
- 238000005086 pumping Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 4
- 238000009835 boiling Methods 0.000 description 3
- 238000007689 inspection Methods 0.000 description 3
- 238000006073 displacement reaction Methods 0.000 description 2
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- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
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- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B9/00—Machines or apparatus for drying solid materials or objects at rest or with only local agitation; Domestic airing cupboards
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Abstract
The invention relates to the field of drying of batteries and super capacitors, in particular to an online moisture detection method in a vacuum drying process of a battery, which comprises the following steps: and (4) replacing the working medium, preheating, maintaining pressure and calculating the online moisture value x of the battery. The invention has the advantages that: the method can monitor the moisture value in the battery on line and in real time, and the baking consistency of the battery is good; after the battery is baked, the battery is not required to be manually damaged, the moisture of the battery is not required to be detected in an off-line mode through a Karl Fischer moisture tester, the battery directly flows to the next procedure, the production efficiency can be greatly improved, the production cost can be greatly reduced, and the labor cost and the equipment purchasing cost can be saved.
Description
Technical Field
The invention relates to the field of drying of batteries and super capacitors, in particular to an online moisture detection method in a vacuum drying process of batteries.
Background
The battery baking and drying are indispensable key processes of the current power battery, and the baking and drying degree and consistency directly influence the performance and quality of the battery. However, in the prior art, the battery is baked by adopting a time control method, and the drying of the battery is completed by defining the vacuum drying time of the oven on the premise of determining the function of the oven. For example, chinese patent application No. CN201810580168.2 discloses a method for rapidly drying a power battery cell, which includes the following steps: step one, spraying a black ink layer on the surface of a battery shell, and/or performing frosting treatment on the surface of the battery shell, wherein the roughness Ra is 0.8-1.6 mu m; step two, placing the bare cell into the treated cell shell, and assembling the cell according to a conventional assembly process; step three, placing the battery in a vacuum drying furnace, and heating for 0.2-2 hours to 80-110 ℃; step four, after the temperature rise is finished, vacuumizing the vacuum drying furnace to enable the vacuum degree to be less than or equal to 500Pa, keeping the temperature to be 80-110 ℃, and baking for 4-10 hours; and step five, taking out the battery to test the water content after baking is finished.
This vacuum drying mode has significant drawbacks, mainly manifested by: the initial moisture of batteries of different batches in different seasons is different, even the initial moisture is greatly different, the batteries are easy to dry when the initial moisture is small, the drying time of the batteries with more initial moisture is longer, and according to the same drying time, some drying time is too long, or some drying time is insufficient. In the process of automatic vacuum drying of battery batches, it is impossible to carry out sampling inspection on each box of battery cores, and even if the sampling inspection is carried out, the box of battery cores cannot be represented to be dried in place. In order to ensure that the battery cells can be dried in place, the vacuum drying time of the battery cells can be prolonged as much as possible, so that the drying capacity is influenced and energy is greatly wasted; secondly, the battery is damaged when the battery core is periodically checked, and a special moisture measuring instrument is used for measuring moisture, so that a certain time is needed, and the normal production rhythm is possibly influenced. This type of inspection is therefore costly to inspect. There is an urgent need to find a new method and means for substitution.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the existing vacuum drying process of the battery has the technical problems that the drying degree of the battery cannot be accurately detected in real time, the battery cannot be sufficiently dried, the production cost is high, and the production efficiency is low.
The invention solves the technical problems through the following technical means: an online moisture detection method in a vacuum drying process of a battery comprises the following steps:
s1 working medium replacement
Putting the battery into an oven, closing a sealing door, vacuumizing to P, and then filling replacement gas until the pressure is normal;
s2 preheating
Starting a heating function of the oven, setting the temperature T of the vacuum drying process, and heating and preheating the battery in the oven for a time T;
s3 pressure maintaining
Calculating the vacuum degree change rate in the oven during pressure maintaining; detecting vacuum degree pressure maintaining time tHealth-care product(ii) a And calculating the online moisture value x of the baked battery.
In practical application, the online moisture detection method in the vacuum drying process of the battery is integrated into a set of simple and practical detection method by utilizing the characteristic of water evaporation in the vacuum drying process of the battery and combining parameters such as the temperature, the vacuum degree and the time of the battery (battery core) in an oven and the rate of water evaporation, and the online moisture judgment of the battery in the vacuum drying process is realized. The vacuum drying of the battery is selected to be carried out in a vacuum environment because the boiling point of water is reduced in the vacuum environment, the water is easy to evaporate, and the battery is prevented from being oxidized during drying. The method can monitor the moisture value in the battery on line and in real time, and the baking consistency of the battery is good; after the battery is baked, the battery is not required to be manually damaged, the moisture of the battery is not required to be detected in an off-line mode through a Karl Fischer moisture tester, the battery directly flows to the next procedure, the production efficiency can be greatly improved, the production cost can be greatly reduced, and the labor cost and the equipment purchasing cost can be saved.
Preferably, step s3 specifically includes:
after the preheating of the battery is finished, carrying out one-stage pressure maintaining, wherein the pressure maintaining process comprises the following steps: vacuumizing to initial vacuum degree PInitialThe water in the battery is heated and vaporized in the oven, the vacuum degree of the oven cavity is gradually reduced, and the vacuum degree is reduced to the circulating vacuum degree PCirculation ofThen vacuumized to PInitialThen at PInitial-PCirculation ofThe battery is subjected to cyclic vacuumizing and pressure maintaining, and water in the battery is taken away along with continuous vacuumizing, so that the batteryThe internal water content gradually decreases when the vacuum degree is from PInitialDown to PCirculation ofVacuum degree pressure maintaining time tHealth-care productGreater than a pressure-maintaining critical time tA segment ofCalculating that the on-line water content value x of the battery is less than the critical water content value x of one section of pressure maintainingA segment of；
In one-stage pressure maintaining, if the online moisture value x of the battery is less than the qualified moisture value xQualifiedIf not, entering the latter stage of pressure maintaining, and the initial vacuum degree P of the latter stage of pressure maintainingInitialThe value is less than the initial vacuum degree P of the previous sectionInitialNumerical value, cyclic vacuum degree P at last stage of pressure maintainingCirculation ofThe value of the circulating vacuum degree P is smaller than that of the previous sectionCirculation ofThe pressure maintaining process is repeated in the subsequent pressure maintaining process, the flow of the pressure maintaining process in each section is the same, and only the parameters are different, until the online moisture value x of the battery is calculated to be smaller than the qualified moisture value xQualifiedAnd stopping under the condition of pressure maintaining.
Preferably, the pressure maintaining process is carried out in four stages, namely first-stage pressure maintaining, second-stage pressure maintaining, third-stage pressure maintaining and fourth-stage pressure maintaining.
According to the invention, the moisture is gradually pumped away in the whole vacuumizing process by a step-type pumping method, the required vacuum degree is higher and higher along with the decrease of the moisture in the battery, and the step-type pressure maintaining is formed by multi-stage pressure maintaining, wherein the vacuum degree value is gradually reduced in the pressure maintaining process step by step and is gradual, so that the moisture value after the battery is dried meets the qualified requirement.
Optimized, in one-stage pressure holding, PInitial10000-Circulation of30000-A segment ofIs 1000PPM, tA segment ofIs 600S.
Optimized, two-stage pressure holding, PInitial1000-Circulation of3000 plus 5000Pa, critical moisture value x of two-stage pressure maintainingTwo segment800PPM, two-stage pressure maintaining critical time tTwo segmentIs 300S.
Optimized, three-stage pressure maintenance, PInitialIs 100pa, PCirculation of500-800Pa, three-stage pressure-maintaining critical water content value xThree sections600PPM, three-stage pressure maintaining critical time tThree sectionsIs 600S.
Optimized, four-stage pressure maintenance, PInitialIs 10-50pa, PCirculation of100pa, critical moisture value x of four-stage pressure maintainingFour sections500PPM, four-stage pressure maintaining critical time tFour sectionsIs 360S.
Optimally, in step s1, P is 45-55 pa.
Optimally, in step s1, the leakage rate of the oven is not more than 3 Pa.L/s, and the replacement gas is nitrogen or dry gas with the dew point of less than or equal to-40 ℃.
Optimally, in the step s2, the temperature T of the vacuum drying process ranges from 80 ℃ to 100 ℃, and the preheating time T ranges from 60min to 180 min.
The invention has the advantages that:
in practical application, the online moisture detection method in the vacuum drying process of the battery is integrated into a set of simple and practical detection method by utilizing the characteristic of water evaporation in the vacuum drying process of the battery and combining parameters such as the temperature, the vacuum degree and the time of the battery (battery core) in an oven and the rate of water evaporation, and the online moisture judgment of the battery in the vacuum drying process is realized. The vacuum drying of the battery is selected to be carried out in a vacuum environment because the boiling point of water is reduced in the vacuum environment, the water is easy to evaporate, and the battery is prevented from being oxidized during drying. In practical application, the dry moisture value of the battery can hardly meet the requirement only by once pressure maintaining. According to the invention, the moisture is gradually pumped away in the whole vacuumizing process by a step-type pumping method, the required vacuum degree is higher and higher along with the decrease of the moisture in the battery, and the step-type pressure maintaining is formed by multi-stage pressure maintaining, wherein the vacuum degree value is gradually reduced in the pressure maintaining process step by step and is gradual, so that the moisture value after the battery is dried meets the qualified requirement. The method can monitor the moisture value in the battery on line and in real time, and the baking consistency of the battery is good; after the battery is baked, the battery is not required to be manually damaged, the moisture of the battery is not required to be detected in an off-line mode through a Karl Fischer moisture tester, the battery directly flows to the next procedure, the production efficiency can be greatly improved, the production cost can be greatly reduced, and the labor cost and the equipment purchasing cost can be saved.
Drawings
FIG. 1 is a schematic diagram of an online moisture detection method in a vacuum drying process of a battery according to an embodiment of the present invention;
FIG. 2 is a flow chart of an online moisture detection method in a vacuum drying process of a battery according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows:
referring to fig. 1 and 2, an online moisture detection method in a vacuum drying process of a battery comprises the following steps:
s1 working medium replacement
The battery is placed in an oven, a sealing door is closed, the leakage rate of the oven is not more than 3 Pa.L/s, the oven is vacuumized to P, P is 45-55Pa, the vacuumizing equipment is the prior art and is commercially available, and the detection of the vacuum degree can be realized by arranging a detection device, such as a vacuum gauge and the like. Then filling displacement gas until the pressure is normal (101325pa), wherein the displacement gas is nitrogen or dry gas with the dew point less than or equal to minus 40 ℃; the nitrogen does not contain moisture, so the nitrogen is used as a working medium.
s2 preheating
Starting a heating function of the oven, setting the temperature T of the vacuum drying process, and heating and preheating the battery in the oven for a time T;
the temperature T of the vacuum drying process is in the range of 80-100 ℃. The preheating time t ranges from 60min to 180 min. The parameters such as the temperature T of the vacuum drying process, the preheating time T and the like can be set according to the battery material system and the model.
s3 pressure maintaining
In the pressure maintainingCalculating the vacuum degree change rate in the oven through a first digital module; detecting the vacuum degree pressure maintaining time t by the second digital moduleHealth-care product(ii) a Utilizing a third digital module to maintain the pressure according to the vacuum degree change rate and the vacuum degreeHealth-care productAnd calculating the online moisture value x of the baked battery.
Specifically, in each section of pressure maintaining, a corresponding relationship exists between a specific pressure maintaining range and pressure maintaining time and an online moisture value of the battery, in the specific pressure maintaining range, when the pressure maintaining time is greater than a specific value, the online moisture value of the battery is correspondingly smaller than the corresponding value, and specific details are found in each section of pressure maintaining data, namely, whether the online moisture value of the battery meets the condition of entering the next section of pressure maintaining or meets the moisture value requirement can be obtained by monitoring the pressure maintaining time.
In this embodiment, a controller is provided, and the first digital module, the second digital module, and the third digital module are integrated in the controller to implement corresponding functions such as detection, calculation, and the like.
The vacuum gauge or other devices capable of detecting the vacuum degree are connected to the controller, so that the detected vacuum degree data are transmitted to the controller; the pressure maintaining time can be detected through a second digital module in the controller, the vacuum degree change rate is calculated through data such as the detected vacuum degree, the detected time and the like, and then the online moisture value x of the baked battery is calculated through the vacuum degree change rate and the detected time data.
The controller controls the work of the vacuum pumping equipment according to the detection, calculation and calculation results, and can be controlled by adopting a PLC.
Step s3 specifically includes:
after the preheating of the battery is finished, carrying out one-stage pressure maintaining, wherein the pressure maintaining process comprises the following steps: vacuumizing to initial vacuum degree PInitialThe water in the battery is heated and vaporized in the oven, the vacuum degree of the oven cavity is gradually reduced, and the vacuum degree is reduced to the circulating vacuum degree PCirculation ofThen vacuumized to PInitialThen at PInitial-PCirculation ofThe water in the battery is gradually reduced along with the continuous vacuumizing to take away the water in the batteryThe vacuum degree is changed from P along with the pressure maintainingInitialDown to PCirculation ofVacuum degree pressure maintaining time tHealth-care productWill become larger when the vacuum degree is from PInitialDown to PCirculation ofVacuum degree pressure maintaining time tHealth-care productGreater than a pressure-maintaining critical time tA segment ofVacuum degree pressure maintaining time tHealth-care productNamely the air release time of the battery, the third digital module calculates that the online water content value x of the battery is less than the critical water content value x of one section of pressure maintainingA segment ofIn one stage of pressure maintaining, PInitial20000pa, PCirculation ofIs 30000pa, xA segment ofIs 1000PPM, tA segment ofIs 600S.
In one-stage pressure maintaining, if the online moisture value x of the battery is less than the qualified moisture value xQualifiedIf not, entering the latter stage of pressure maintaining, and the initial vacuum degree P of the latter stage of pressure maintainingInitialThe value is less than the initial vacuum degree P of the previous sectionInitialNumerical value, cyclic vacuum degree P at last stage of pressure maintainingCirculation ofThe value of the circulating vacuum degree P is smaller than that of the previous sectionCirculation ofThe pressure maintaining process is repeated in the subsequent pressure maintaining process, the flow of the pressure maintaining process in each section is the same, and only the parameters are different, until the online moisture value x of the battery is calculated to be smaller than the qualified moisture value xQualifiedAnd stopping under the condition of pressure maintaining.
Specifically, in this embodiment, the pressure maintaining process is performed in four stages, which are a first stage pressure maintaining stage, a second stage pressure maintaining stage, a third stage pressure maintaining stage, and a fourth stage pressure maintaining stage.
In two-stage pressure maintaining, PInitialIs 2000pa, PCirculation of3000pa, critical moisture value x of two-stage pressure maintainingTwo segment800PPM, two-stage pressure maintaining critical time tTwo segmentIs 300S, and specifically comprises the following steps:
vacuumizing to an initial vacuum degree of 2000pa, heating and vaporizing the water of the battery in the oven, gradually reducing the vacuum degree of the cavity of the oven, vacuumizing to 2000pa when the vacuum degree is reduced to a circulating vacuum degree of 3000pa, then circularly vacuumizing and maintaining pressure between 2000pa and 3000pa, taking away the water of the battery along with continuous vacuumizing, gradually reducing the water in the battery, and reducing the vacuum degree from 2000pa to 3000pa when the vacuum degree is maintained for a vacuum degree pressure maintaining time tHealth-care productIs more than a holding critical time of 300S,and the third digital module calculates that the online water content value x of the battery is smaller than the critical water content value 800PPM of one section of pressure maintaining, and enters the next section of pressure maintaining.
In three-stage pressure maintaining, PInitialIs 100pa, PCirculation of500pa, critical moisture value x of three-stage pressure maintainingThree sections600PPM, three-stage pressure maintaining critical time tThree sectionsIs 600S.
Specifically, the vacuum degree is pumped to 100pa of initial vacuum degree, the moisture of the battery is heated and vaporized in the oven, the vacuum degree of the cavity of the oven is gradually reduced, when the vacuum degree is reduced to 500pa of circulating vacuum degree, the vacuum degree is pumped to 100pa, then the vacuum degree is circularly pumped and the pressure is maintained between 100pa and 500pa, the moisture of the battery is taken away along with continuous vacuum pumping, the moisture in the battery is gradually reduced, and when the vacuum degree is reduced to 500pa from 100pa, the pressure maintaining time t of the vacuum degree is keptHealth-care productAnd when the pressure maintaining critical time is more than 600S, the third digital module calculates that the online water content value x of the battery is less than the pressure maintaining critical water content value 600PPM, and the next pressure maintaining is carried out.
In four-stage pressure maintaining, PInitialIs 50pa, PCirculation of100pa, critical moisture value x of four-stage pressure maintainingFour sections500PPM, four-stage pressure maintaining critical time tFour sections360S, the acceptable moisture value x in this exampleQualifiedIs 500 PPM.
Specifically, vacuumizing to an initial vacuum degree of 50pa, heating and vaporizing the moisture of the battery in the oven, gradually reducing the vacuum degree of the cavity of the oven, vacuumizing to 50pa when the vacuum degree is reduced to a circulating vacuum degree of 100pa, then circularly vacuumizing and maintaining the pressure between 50pa and 100pa, taking away the moisture of the battery along with continuous vacuumizing, gradually reducing the moisture in the battery, and reducing the vacuum degree from 50pa to 100pa when the vacuum degree is reduced to the vacuum degree pressure maintaining time t of 100paHealth-care productAnd when the pressure is greater than the critical time 360S for one section of pressure maintaining, the third digital module calculates that the online water content value x of the battery is less than the critical water content value 500PPM for one section of pressure maintaining, and after four sections of pressure maintaining, the water content value requirement meets the quality requirement, the vacuum drying of the battery is finished, and the operation is automatically finished.
Example two:
the difference between this embodiment and the first embodiment is:
in the first-stage pressure maintaining: pInitial10000pa, PCirculation of50000 pa;
and (3) in two-stage pressure maintaining: pInitialIs 1000pa, PCirculation of5000 pa;
and (3) three-stage pressure maintaining: pCirculation ofIs 800 pa;
and in the four-stage pressure maintaining: pInitialIs 10 pa.
Example three:
the difference between this embodiment and the first embodiment is:
in the first-stage pressure maintaining: pInitialIs 15000pa, PCirculation of40000 pa;
and (3) in two-stage pressure maintaining: pInitialIs 1500pa, PCirculation of4000 pa;
and (3) three-stage pressure maintaining: pCirculation ofIs 650 pa;
and in the four-stage pressure maintaining: pInitialIs 30 pa.
It should be noted that:
the specific pressure maintaining process in the invention is not limited to four-stage pressure maintaining, as long as after the pressure maintaining, the online moisture value x of the battery is calculated to be less than the qualified moisture value xQualifiedAnd stopping the pressure maintaining. For example, after a period of pressure maintaining, the online water content value x of the battery is calculated to be less than the qualified water content value xQualifiedAnd the pressure can be maintained and the valve can be closed. If the online water content x of the battery does not meet the requirement after the four-stage pressure maintaining, continuing the next stage pressure maintaining until the online water content x of the battery is calculated to be less than the qualified water content xQualifiedAnd stopping under the condition of pressure maintaining.
In practical application, the online moisture detection method in the vacuum drying process of the battery is integrated into a set of simple and practical detection method by utilizing the characteristic of water evaporation in the vacuum drying process of the battery and combining parameters such as the temperature, the vacuum degree and the time of the battery (battery core) in an oven and the rate of water evaporation, and the online moisture judgment of the battery in the vacuum drying process is realized. The vacuum drying of the battery is selected to be carried out in a vacuum environment because the boiling point of water is reduced in the vacuum environment, the water is easy to evaporate, and the battery is prevented from being oxidized during drying. According to the invention, the moisture is gradually pumped away in the whole vacuumizing process by a step-type pumping method, the required vacuum degree is higher and higher along with the decrease of the moisture in the battery, and the step-type pressure maintaining is formed by multi-stage pressure maintaining, wherein the vacuum degree value is gradually reduced in the pressure maintaining process step by step and is gradual, so that the moisture value after the battery is dried meets the qualified requirement. The method can monitor the moisture value in the battery on line and in real time, and the baking consistency of the battery is good; after the battery is baked, the battery is not required to be manually damaged, the moisture of the battery is not required to be detected in an off-line mode through a Karl Fischer moisture tester, the battery directly flows to the next procedure, the production efficiency can be greatly improved, the production cost can be greatly reduced, and the labor cost and the equipment purchasing cost can be saved.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. An online moisture detection method in a vacuum drying process of a battery is characterized in that: the method comprises the following steps:
s1 working medium replacement
Putting the battery into an oven, closing a sealing door, vacuumizing to P, and then filling replacement gas until the pressure is normal;
s2 preheating
Starting a heating function of the oven, setting the temperature T of the vacuum drying process, and heating and preheating the battery in the oven for a time T;
s3 pressure maintaining
Calculating the vacuum degree change rate in the oven during pressure maintaining; detecting vacuum degree pressure maintaining time tHealth-care product(ii) a And calculating the online moisture value x of the baked battery.
2. The on-line moisture detection method in the vacuum drying process of the battery according to claim 1, characterized in that:
step s3 specifically includes:
after the preheating of the battery is finished, carrying out one-stage pressure maintaining, wherein the pressure maintaining process comprises the following steps: vacuumizing to initial vacuum degree PInitialThe water in the battery is heated and vaporized in the oven, the vacuum degree of the oven cavity is gradually reduced, and the vacuum degree is reduced to the circulating vacuum degree PCirculation ofThen vacuumized to PInitialThen at PInitial-PCirculation ofThe water in the battery is gradually reduced along with the continuous vacuumizing to take away the water in the battery, and when the vacuum degree is from PInitialDown to PCirculation ofVacuum degree pressure maintaining time tHealth-care productGreater than a pressure-maintaining critical time tA segment ofCalculating that the on-line water content value x of the battery is less than the critical water content value x of one section of pressure maintainingA segment of；
In one-stage pressure maintaining, if the online moisture value x of the battery is less than the qualified moisture value xQualifiedIf not, entering the latter stage of pressure maintaining, and the initial vacuum degree P of the latter stage of pressure maintainingInitialThe value is less than the initial vacuum degree P of the previous sectionInitialNumerical value, cyclic vacuum degree P at last stage of pressure maintainingCirculation ofThe value of the circulating vacuum degree P is smaller than that of the previous sectionCirculation ofThe pressure maintaining process is repeated in the subsequent pressure maintaining process, the flow of the pressure maintaining process in each section is the same, and only the parameters are different, until the online moisture value x of the battery is calculated to be smaller than the qualified moisture value xQualifiedAnd stopping under the condition of pressure maintaining.
3. The on-line moisture detection method in the vacuum drying process of the battery according to claim 2, characterized in that: the pressure maintaining process is carried out in four stages, namely first-stage pressure maintaining, second-stage pressure maintaining, third-stage pressure maintaining and fourth-stage pressure maintaining.
4. The on-line moisture detection method in the vacuum drying process of the battery according to claim 3, characterized in that: in one stage of pressure maintaining, PInitial10000-Circulation of30000-A segment ofIs 1000PPM, tA segment ofIs 600S.
5. The on-line moisture detection method in the vacuum drying process of the battery according to claim 3, characterized in that: in two-stage pressure maintaining, PInitial1000-Circulation of3000 plus 5000Pa, critical moisture value x of two-stage pressure maintainingTwo segment800PPM, two-stage pressure maintaining critical time tTwo segmentIs 300S.
6. The on-line moisture detection method in the vacuum drying process of the battery according to claim 3, characterized in that: in three-stage pressure maintaining, PInitialIs 100pa, PCirculation of500-800Pa, three-stage pressure-maintaining critical water content value xThree sections600PPM, three-stage pressure maintaining critical time tThree sectionsIs 600S.
7. The on-line moisture detection method in the vacuum drying process of the battery according to claim 3, characterized in that: in four-stage pressure maintaining, PInitialIs 10-50pa, PCirculation of100pa, critical moisture value x of four-stage pressure maintainingFour sections500PPM, four-stage pressure maintaining critical time tFour sectionsIs 360S.
8. The on-line moisture detection method in the vacuum drying process of the battery according to claim 1, characterized in that: in step s1, P is 45-55 pa.
9. The on-line moisture detection method in the vacuum drying process of the battery according to claim 1, characterized in that: in step s1, the leakage rate of the oven is not more than 3 Pa.L/s, and the replacement gas is nitrogen or dry gas with the dew point of less than or equal to-40 ℃.
10. The on-line moisture detection method in the vacuum drying process of the battery according to claim 1, characterized in that: in step s2, the temperature T of the vacuum drying process ranges from 80 ℃ to 100 ℃, and the preheating time T ranges from 60min to 180 min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202110614816.3A CN113358824A (en) | 2021-06-02 | 2021-06-02 | Online moisture detection method in vacuum drying process of battery |
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| CN202110614816.3A CN113358824A (en) | 2021-06-02 | 2021-06-02 | Online moisture detection method in vacuum drying process of battery |
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