CN111413370A - Method for detecting moisture content of battery pole piece - Google Patents
Method for detecting moisture content of battery pole piece Download PDFInfo
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- CN111413370A CN111413370A CN202010202601.6A CN202010202601A CN111413370A CN 111413370 A CN111413370 A CN 111413370A CN 202010202601 A CN202010202601 A CN 202010202601A CN 111413370 A CN111413370 A CN 111413370A
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- pole piece
- moisture content
- resistivity
- relation curve
- detection method
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- 238000000034 method Methods 0.000 title claims abstract description 18
- 238000001514 detection method Methods 0.000 claims abstract description 20
- 238000012360 testing method Methods 0.000 claims abstract description 16
- 239000000463 material Substances 0.000 claims abstract description 11
- 230000007613 environmental effect Effects 0.000 claims abstract description 5
- 239000000523 sample Substances 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 229910002804 graphite Inorganic materials 0.000 claims description 6
- 239000010439 graphite Substances 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims description 4
- 239000007924 injection Substances 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 4
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 4
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 4
- 229910001416 lithium ion Inorganic materials 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 229910021383 artificial graphite Inorganic materials 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 229910021382 natural graphite Inorganic materials 0.000 description 2
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/048—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance for determining moisture content of the material
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
Abstract
The invention discloses a method for detecting the moisture content of a battery pole piece, which comprises the following steps: (1) establishing a relation curve of the resistivity and the moisture content of the pole piece aiming at each battery pole piece material; (2) testing the resistivity of the pole piece to be tested; (3) and (3) obtaining the moisture content of the pole piece to be detected according to the resistivity measured in the step (2) and the relation curve of the resistivity and the moisture content of the pole piece corresponding to the pole piece material in the step (1). The method disclosed by the invention can realize accurate detection of the moisture content of the pole piece, has a small error rate, and has the advantages of environmental friendliness, low cost and simplicity in operation.
Description
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a method for detecting the moisture content of a battery pole piece.
Background
In the production process of the lithium ion battery, the production environment and the water content of the pole piece need to be strictly controlled, if the water content does not meet the requirement, the water can generate side reaction with electrolyte and the like, so that the defects of bulging, low capacity and the like are caused, and the performance of the battery is seriously influenced. Therefore, accurate detection of the moisture content in the pole piece is crucial. At present, a Karl-Fischer moisture tester is often adopted for detection, but the following defects exist: 1. the Karl Fischer reagent is a solution mainly composed of iodine, sulfur dioxide, pyridine and methanol, wherein the sulfur dioxide and the pyridine have extremely high volatility and great harm to human bodies and the environment; 2. the Karl-Fischer reagent is a consumable product and has high cost; 3. the method is complex to operate and needs professional personnel to operate.
Therefore, an environment-friendly method for detecting the moisture content of the pole piece, which is low in cost and simple to operate, is urgently needed in the field.
Disclosure of Invention
In order to make up for the defects of the prior art, the invention provides a method for detecting the moisture content of a battery pole piece.
The technical problem of the invention is solved by the following technical scheme:
a method for detecting the moisture content of a battery pole piece comprises the following steps:
(1) establishing a relation curve of the resistivity and the moisture content of the pole piece aiming at each battery pole piece material;
(2) testing the resistivity of the pole piece to be tested;
(3) and (3) obtaining the moisture content of the pole piece to be detected according to the resistivity measured in the step (2) and the relation curve of the resistivity and the moisture content of the pole piece corresponding to the pole piece material in the step (1).
Preferably, in the step (1), the number of pole pieces required for establishing the relation curve of the resistivity and the moisture content of the pole pieces is 30-100.
Preferably, the resistivity of the pole piece in the steps (1) and (2) is measured by using a two-probe pole piece integral resistivity measurement method in a constant environment, wherein the constant environment is as follows: the environmental temperature is 25 plus or minus 5 ℃, and the dew point is less than or equal to minus 45 ℃.
Preferably, the moisture content of the pole piece in the step (1) is detected by a Karl Fischer moisture tester.
Preferably, the resistivity of the pole piece in the steps (1) and (2) is detected by taking the pole piece baked before liquid injection as a detection object.
Preferably, the battery pole piece is a negative pole piece made of graphite, and the relation curve of resistivity and moisture content of the baked pole piece satisfies the following conditions: the resistivity x is more than or equal to 10 omega cm, and the moisture content y is-10.47 x + 508.5.
Preferably, the resistivity of the pole piece in the steps (1) and (2) is that the pole piece just coated is a detection object.
Preferably, the battery pole piece is a negative pole piece, the material of the negative pole piece is graphite, and a relation curve of the resistivity and the moisture content of the pole piece just coated meets the following requirements: the resistivity x is less than 10 omega cm, and the moisture content y is-227.9 x + 3314.2.
Compared with the prior art, the invention has the advantages that: the method provided by the invention can realize accurate detection of the moisture content of the pole piece, has a small error rate, and has the advantages of environmental friendliness, low cost and simplicity in operation.
Drawings
FIG. 1 is a graph of resistivity versus moisture content for a pole piece in example 1 of the present invention;
FIG. 2 is a graph of resistivity versus moisture content for the pole piece of example 2 of the present invention.
Detailed Description
The invention will be further described with reference to the accompanying drawings and preferred embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention, as the embodiments and features of the embodiments may be combined with each other in the present application without conflict.
The invention provides a method for detecting the moisture content of a battery pole piece, which comprises the following steps:
(1) establishing a relation curve of the resistivity and the moisture content of the pole piece aiming at each battery pole piece material;
(2) testing the resistivity of the pole piece to be tested;
(3) and (3) obtaining the moisture content of the pole piece to be detected according to the resistivity measured in the step (2) and the relation curve of the resistivity and the moisture content of the pole piece corresponding to the pole piece material in the step (1).
In a preferred embodiment, in the step (1), the number of pole pieces required for establishing the relation curve of the resistivity and the moisture content of the pole piece is 30-100.
In a preferred embodiment, the resistivity of the pole pieces in the steps (1) and (2) is measured by using a two-probe pole piece overall resistivity measurement method in a constant environment, wherein the constant environment is as follows: the environmental temperature is 25 plus or minus 5 ℃, and the dew point is less than or equal to minus 45 ℃.
In a preferred embodiment, the moisture content of the pole piece in the step (1) is detected by a Karl Fischer moisture meter.
In a preferred embodiment, the resistivity of the pole piece in the steps (1) and (2) is detected by using the pole piece baked before injection. In a preferred embodiment, the battery pole piece is a negative pole piece, the material of the negative pole piece is graphite (such as artificial graphite and/or natural graphite), and the relation curve of the resistivity and the moisture content of the baked pole piece satisfies the following conditions: the resistivity x is more than or equal to 10 omega cm, and the moisture content y is-10.47 x + 508.5.
In a preferred embodiment, the resistivity of the electrode sheet in the steps (1) and (2) is that the electrode sheet just coated is a detection object.
In a preferred embodiment, the battery pole piece is a negative pole piece, the material of the negative pole piece is graphite (such as artificial graphite and/or natural graphite), and the relation curve of the resistivity and the moisture content of the pole piece just coated satisfies the following conditions: the resistivity x is less than 10 omega cm, and the moisture content y is-227.9 x + 3314.2.
The battery can be, for example, a lithium ion battery, and when the relation curve between the resistivity and the moisture content of the pole piece is established in the step (1), the pole piece of the same batch can be adopted, samples (30-100) are randomly extracted from the pole piece to be measured, the resistivity and the moisture content of the pole piece of the sample are measured, and then the relation curve between the resistivity and the moisture content of the pole piece is established according to the data of the resistivity and the moisture content. The present invention will be further explained by taking the artificial graphite as an example of the negative electrode sheet of the lithium ion battery.
Example 1
The method comprises the following steps of taking a baked roll core before liquid injection as a detection object, and testing the moisture content of a negative plate, wherein the method comprises the following specific steps:
1. randomly drawing 40 test samples;
2. numbering the samples, and placing the samples into a sample bag for sealed storage;
3. respectively testing the resistivity and the moisture content of the pole piece of 30 samples, wherein the data correspond to one another, and are shown in the following table 1;
4. obtaining a relation curve of the resistivity and the moisture content of the pole piece according to the test data;
5. testing the resistivity of the remaining 10 pole pieces to be detected;
6. and obtaining the moisture content of the pole piece to be detected according to the resistivity of the pole piece and the relation curve of the resistivity of the pole piece and the moisture content.
Wherein, the resistivity in the steps 3 and 5 is measured by adopting a two-probe pole piece integral resistivity measuring method, and the moisture content in the step 3 is measured by using a Karl-Fischer moisture measuring instrument; the sampling environment and the testing environment were dry rooms with a temperature of 25 + -5 deg.C and a dew point of-45 deg.C (in this case about-50 deg.C).
Table 1:
the relation curve of the resistivity of the pole piece and the moisture content can be obtained through the data as follows: y is-10.47 x +508.5, x is not less than 10
The data of the remaining 10 sample negative electrode sheets in the above step 5 are shown in the following table 2:
table 2:
note: the "measured value of moisture content" in the above table was measured by a Karl Fischer moisture meter.
As can be seen from Table 2: the difference between the calculated value of the moisture content and the measured value of the moisture content is small, and the error rate is less than 5%, so that the moisture content of the pole piece can be accurately detected by the pole piece moisture content detection method in the embodiment, namely, a conversion characterization mode of the moisture content through the resistivity of the pole piece is feasible.
Example 2
Taking the cathode roll which is just coated as a detection object, and testing the moisture content of the cathode sheet, wherein the method comprises the following specific steps:
1. randomly drawing 40 test samples;
2. numbering the samples, and placing the samples into a sample bag for sealed storage;
3. respectively testing the resistivity and the moisture content of the pole piece of 30 samples, wherein the data correspond to one another, and are shown in the following table 3;
4. obtaining a relation curve of the resistivity and the moisture content of the pole piece according to the test data;
5. testing the resistivity of the remaining 10 pole pieces to be detected;
6. and obtaining the moisture content of the pole piece to be detected according to the resistivity of the pole piece and the relation curve of the resistivity of the pole piece and the moisture content.
Wherein, the resistivity in the steps 3 and 5 is measured by adopting a two-probe pole piece integral resistivity measuring method, and the moisture content in the step 3 is measured by using a Karl-Fischer moisture measuring instrument; the sampling environment and the testing environment were dry rooms with a temperature of 25 + -5 deg.C and a dew point of-45 deg.C (in this case about-50 deg.C).
Table 3:
the relation curve of the resistivity of the pole piece and the moisture content can be obtained through the data: y is-227.9 x +3314.2 and x is less than 10
The data for the remaining 10 sample negative electrode tabs in step 5 above are shown in table 4 below:
table 4:
note: the "measured value of moisture content" in the above table was measured by a Karl Fischer moisture meter.
As can be seen from Table 4: the difference between the calculated value of the moisture content and the measured value of the moisture content is small, and the error rate is less than 5%, so that the moisture content of the pole piece can be accurately detected by the pole piece moisture content detection method in the embodiment, namely, a conversion characterization mode of the moisture content through the resistivity of the pole piece is feasible.
The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several equivalent substitutions or obvious modifications can be made without departing from the spirit of the invention, and all the properties or uses are considered to be within the scope of the invention.
Claims (8)
1. A method for detecting the moisture content of a battery pole piece is characterized by comprising the following steps:
(1) establishing a relation curve of the resistivity and the moisture content of the pole piece aiming at each battery pole piece material;
(2) testing the resistivity of the pole piece to be tested;
(3) and (3) obtaining the moisture content of the pole piece to be detected according to the resistivity measured in the step (2) and the relation curve of the resistivity and the moisture content of the pole piece corresponding to the pole piece material in the step (1).
2. The detection method according to claim 1, characterized in that: in the step (1), the number of pole pieces required for establishing a relation curve between the resistivity of the pole piece and the moisture content is 30-100.
3. The detection method according to claim 1, characterized in that: the resistivity of the pole pieces in the steps (1) and (2) is measured in a constant environment by adopting a two-probe pole piece integral resistivity measuring method, wherein the constant environment refers to that: the environmental temperature is 25 plus or minus 5 ℃, and the dew point is less than or equal to minus 45 ℃.
4. The detection method according to claim 1, characterized in that: and (2) detecting the moisture content of the pole piece in the step (1) by using a Karl Fischer moisture tester to obtain the moisture content.
5. The detection method according to any one of claims 1 to 4, characterized in that: the resistivity of the pole piece in the steps (1) and (2) is to take the pole piece baked before liquid injection as a detection object.
6. The detection method according to claim 5, characterized in that: the battery pole piece is a negative pole piece made of graphite, and the relation curve of resistivity and moisture content of the baked pole piece meets the following requirements: the resistivity x is more than or equal to 10 omega cm, and the moisture content y is-10.47 x + 508.5.
7. The detection method according to any one of claims 1 to 4, characterized in that: the resistivity of the pole piece in the steps (1) and (2) is that the pole piece just coated is a detection object.
8. The detection method according to claim 7, characterized in that: the battery pole piece is a negative pole piece made of graphite, and the relation curve of the resistivity and the moisture content of the pole piece just coated meets the following requirements: the resistivity x is less than 10 omega cm, and the moisture content y is-227.9 x + 3314.2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010202601.6A CN111413370A (en) | 2020-03-20 | 2020-03-20 | Method for detecting moisture content of battery pole piece |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202010202601.6A CN111413370A (en) | 2020-03-20 | 2020-03-20 | Method for detecting moisture content of battery pole piece |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020180448A1 (en) * | 2001-05-18 | 2002-12-05 | Tomonori Imamura | Method for measuring water content of fuel cell based on conductivity of electrolyte |
| EP1717575A1 (en) * | 2005-04-27 | 2006-11-02 | Nederlandse Organisatie voor Toegepast-Natuuurwetenschappelijk Onderzoek TNO | Method for internal testing of materials |
| CN102640341A (en) * | 2009-11-26 | 2012-08-15 | 丰田自动车株式会社 | Fuel cell system and control method of same |
| CN106546711A (en) * | 2017-01-17 | 2017-03-29 | 西安科技大学 | The relational model construction method of frozen soil resistivity and temperature and content of unfrozen water in frozen earth |
| CN208953527U (en) * | 2018-09-13 | 2019-06-07 | 漳州市台美技术研究所有限公司 | A kind of multi-functional moisture tester |
-
2020
- 2020-03-20 CN CN202010202601.6A patent/CN111413370A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020180448A1 (en) * | 2001-05-18 | 2002-12-05 | Tomonori Imamura | Method for measuring water content of fuel cell based on conductivity of electrolyte |
| EP1717575A1 (en) * | 2005-04-27 | 2006-11-02 | Nederlandse Organisatie voor Toegepast-Natuuurwetenschappelijk Onderzoek TNO | Method for internal testing of materials |
| CN102640341A (en) * | 2009-11-26 | 2012-08-15 | 丰田自动车株式会社 | Fuel cell system and control method of same |
| CN106546711A (en) * | 2017-01-17 | 2017-03-29 | 西安科技大学 | The relational model construction method of frozen soil resistivity and temperature and content of unfrozen water in frozen earth |
| CN208953527U (en) * | 2018-09-13 | 2019-06-07 | 漳州市台美技术研究所有限公司 | A kind of multi-functional moisture tester |
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