A method for measuring the thinning area of ​​the pole piece based on a lithium battery coating surface density meter

Abstract

The present invention discloses a method for measuring the thinning area of ​​a pole piece based on a lithium battery coating surface density meter. The method adopts the volume density combined with the surface density values ​​of the non-thinned area and the thinned area collected in real time to calculate the thinning amount of the thinned area relative to the non-thinned area. The coating surface density meter is used to monitor the surface density in real time during the pole piece coating process. The real-time calculation based on the collected surface density data can realize the real-time detection of the thinning amount of the pole piece thinning area.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery detection, in particular to a method for measuring a pole piece thinning area based on a lithium battery coating surface density meter. Background Art

[0002] Lithium battery pole pieces are made of foil and a coating applied to the foil. The coating area of ​​the pole piece is thinner at the edges, dividing the coated area into a non-skimmed area and skimmed areas on either side of the non-skimmed area. To verify whether the size of the skimmed area meets the production requirements of lithium batteries, the skimmed area is inspected. Currently, the skimmed area of ​​lithium batteries is inspected using a micrometer to measure the thickness and width of the skimmed area. This inspection can only be performed on the outermost pole piece after the pole piece coating is completed, and cannot achieve real-time coating inspection of the skimmed area. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for measuring the thinning area of ​​the electrode based on a lithium battery coating surface density meter, which uses the difference in surface density to measure the thinning amount and width value of the electrode thinning area, and the coating surface density meter monitors the surface density in real time during the electrode coating process, thereby realizing real-time detection of the electrode thinning area.

[0004] The technical solution of the present invention is:

[0005] A method for measuring the thinning area of ​​a pole piece based on a lithium battery coating surface density meter specifically includes the following steps:

[0006] (1) Calculate the bulk density of the electrode coating area: Cut a test piece in the electrode coating area, weigh the test piece to obtain its weight m, cross-sectional area S and thickness T, and then calculate the bulk density x of the electrode coating area according to formula (1);

[0007]

[0008] In formula (1), σ 箔材 is the surface density of the foil, T 箔材 is the thickness of the foil, which is a known quantity;

[0009] (2) The coating surface density meter scans the electrode from left to right. When it reaches the left edge of the coating area, the measured surface density σ at the left edge of the coating area is recorded. L Then the coating surface density meter scans the electrode from right to left. When it reaches the right edge of the coating area, the measured surface density σ at the right edge of the coating area is recorded. R ,;

[0010] (3) Calculate the thinning amount of the thinning areas on the left and right sides of the electrode coating area. See formula (2) and formula (3) for details:

[0011] HL =(σ T -σ L )÷x (2);

[0012] H R =(σ T -σ R )÷x (3);

[0013] In formulas (2) and (3), H L is the thinning thickness value of the left thinning area, H R is the thinning thickness value of the thinning area on the right; σ T is the target coating density, is the coating density value set by the coater, and is a known quantity.

[0014] In the step (2), when the left edge of the coating area is reached, the travel distance L1 is recorded, and then the coating surface density meter continues to scan to the right. When the coating surface density measured by the coating surface density meter is equal to the coating surface density target value σ for the first time, T When the coating area reaches the right edge of the coating zone, the travel distance L3 is recorded. Then the coating area density meter continues to scan to the left. When the coating area density measured by the coating area density meter is equal to the coating area density target value σ for the first time, the coating area density meter is scanned to the left. T When the travel distance L4 is recorded, the width of the thinned area on the left and right sides of the electrode coating area is calculated. See formula (4) and formula (5) for details:

[0015] L L =L2-L1 (4);

[0016] L R =L4-L3 (5);

[0017] In formulas (4) and (5), L L is the width of the left thinning area, L R is the width of the thinning area on the right.

[0018] The coating surface density meter is connected to the controller, which receives the surface density data and stroke data collected by the coating surface density meter, and calculates the thinning amount and thinning width of the thinning areas on the left and right sides of the electrode coating area in combination with the volume density x.

[0019] The test piece is taken from the non-thinned area of ​​the electrode coating area.

[0020] The test piece is a circular hole electrode piece punched in the coating area using a knife die or a punch, and the cross-sectional area S of the test piece is the cutting area of ​​the knife die or the punch.

[0021] When the coating surface density meter scans the electrode from left to right or from right to left, when the surface density measured by the coating surface density meter is not less than the surface density of the foil σ for the first time 箔材 Add the set surface density difference σ 差 When the surface density meter reaches the left or right edge of the coating area, the surface density difference σ is set. 差 is a set value. The surface density of the electrode foil area is at least lower than the surface density of the electrode coating area by the set density difference σ 差 .

[0022] The controller is connected to a display screen, and the controller sends the calculated thinning amount and thinning width of the thinning areas on the left and right sides of the pole piece to the display screen for display.

[0023] The weight m, cross-sectional area S and thickness T of the test piece, and the surface density σ of the foil 箔材 , foil thickness T 箔材 are all entered into the controller, and the controller calculates the volume density x.

[0024] The controller converts the surface density σ collected by the coating surface density meter into L and σ R Sent to the display screen for display, surface density σ L is the surface density value of the thinning area on the left, σ R It is the surface density value of the thinning area on the right.

[0025] Advantages of the present invention:

[0026] (1) The non-thinned area and the thinned area of ​​the electrode are both coating areas. Since the coating material is the same, that is, the volume density of the coating area is consistent, the thinning amount of the thinned area relative to the non-thinned area can be calculated by combining the volume density with the surface density values ​​of the non-thinned area and the thinned area collected in real time. Therefore, the present invention uses a coating surface density meter to monitor the surface density in real time during the electrode coating process, and the real-time detection of the thinning amount of the electrode thinned area can be achieved by performing real-time calculation based on the collected surface density data.

[0027] (2) The present invention determines the edge positions on both sides of the thinning area and the edge positions on both sides of the thinning area based on the difference in surface density of different areas of the electrode, thereby determining the width values ​​of the left and right thinning areas. A coating surface density meter is used to monitor the surface density in real time during the electrode coating process. After analyzing and determining the position based on the collected surface density data, the stroke difference calculation is performed to achieve real-time detection of the width value of the thinning area of ​​the electrode;

[0028] (3) The present invention is provided with a controller, which is connected to a display screen. The controller can directly send the calculated thinning amount and width value of the thinning zone to the display screen for intuitive display, so that the inspection personnel can observe the inspection results of the thinning zone in real time during the electrode coating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the division of the electrode foil area, non-thinning area and thinning area.

[0030] Reference numerals: 1 - foil area, 2 - non-thinned area, 3 - left thinned area, 4 - right thinned area. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] A method for measuring the thinning area of ​​a pole piece based on a lithium battery coating surface density meter specifically includes the following steps:

[0033] (1) Calculate the bulk density of the electrode coating area: Use a die cutter or a puncher to punch a circular hole electrode in the non-thinned area 2 of the electrode coating area as a test piece. The cross-sectional area S of the test piece is the cutting area of ​​the die cutter or the puncher. Weigh the test piece to obtain the weight m, use a micrometer to measure the thickness T of the test piece, and then calculate the weight m, cross-sectional area S and thickness T of the test piece, as well as the surface density σ of the foil. 箔材 , foil thickness T 箔材 All are entered into the controller, and the controller calculates the volume density x of the electrode coating area according to formula (1);

[0034]

[0035] In formula (1), the foil surface density σ 箔材 , foil thickness T 箔材 All are known quantities;

[0036] (2) The coating surface density meter scans the electrode from left to right. When it reaches the left edge of the coating area, the measured surface density σ at the left edge of the coating area is recorded. L , and record the travel distance L1 at this time, then the coating surface density meter continues to scan to the right, when the coating surface density measured by the coating surface density meter is equal to the coating surface density target value σ for the first time T When the coating surface density meter scans the electrode from left to right, the surface density measured by the coating surface density meter is not less than the surface density of the foil σ for the first time. 箔材 Add the set surface density difference σ 差 When the surface density meter reaches the left edge of the coating area, the surface density difference σ is set. 差is a set value, the surface density of the electrode foil area 1 is at least lower than the surface density of the electrode coating area by the set density difference σ 差 ;

[0037] (3) The coating surface density meter scans the electrode from right to left. When it reaches the right edge of the coating area, the measured surface density σ at the right edge of the coating area is recorded. R , and record the travel distance L3 at this time, then the coating surface density meter continues to scan to the left, when the coating surface density measured by the coating surface density meter is equal to the coating surface density target value σ for the first time T When the coating surface density meter scans the electrode from right to left, the surface density measured by the coating surface density meter is not less than the surface density of the foil σ for the first time. 箔材 Add the set surface density difference σ 差 When , it is determined that the cloth surface density meter has reached the right edge of the coating area;

[0038] (4) The controller receives the surface density data and stroke data collected by the coating surface density meter, and combines the volume density x to calculate the thinning amount and thinning width of the thinning areas on the left and right sides of the electrode coating area according to formulas (2)-(5);

[0039] H L =(σ T -σ L )÷x (2);

[0040] H R =(σ T -σ R )÷x (3);

[0041] L L =L2-L1 (4);

[0042] L R =L4-L3 (5);

[0043] In formulas (2)-(5), H L is the thinning thickness value (thinning amount) of the left thinning zone 3, H R is the thinning thickness value (thinning amount) of the thinning zone 4 on the right side; σ T is the target value of coating surface density, is the coating density value set by the coating machine, and is a known quantity; L L is the width of the left thinning area, L R is the width of the thinning area on the right;

[0044] (5) The controller is connected to a display screen, which calculates the thinning amount and thinning width of the thinning areas on the left and right sides of the electrode, and the surface density value σ of the thinning area on the left side collected by the coating surface density meter. L and the surface density value σ of the thinning area on the right RAll are sent to the display for display.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring the thinning area of ​​a pole piece based on a lithium battery coating surface density meter, characterized in that: The specific steps include: (1) Calculate the bulk density of the electrode coating area: Cut a test piece in the electrode coating area, weigh the test piece to obtain its weight m, cross-sectional area S and thickness T, and then calculate the bulk density x of the electrode coating area according to formula (1); In formula (1), σ 箔材 is the surface density of the foil, T 箔材 is the thickness of the foil, which is a known quantity; (2) The coating surface density meter scans the electrode from left to right. When it reaches the left edge of the coating area, the measured surface density σ at the left edge of the coating area is recorded. L Then the coating surface density meter scans the electrode from right to left. When it reaches the right edge of the coating area, the measured surface density σ at the right edge of the coating area is recorded. R ; (3) Calculate the thinning amount of the thinning areas on the left and right sides of the electrode coating area. See formula (2) and formula (3) for details: H L =(s T -s L )÷x (2); H R =(s T -s R )÷x (3); In formulas (2) and (3), H L is the thinning thickness value of the left thinning area, H R is the thinning thickness value of the thinning area on the right; σ T is the target coating density, is the coating density value set by the coater, and is a known quantity.

2. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 1, characterized in that: In the step (2), when the left edge of the coating area is reached, the travel distance L1 is recorded, and then the coating surface density meter continues to scan to the right. When the coating surface density measured by the coating surface density meter is equal to the coating surface density target value σ for the first time, T When the coating area reaches the right edge of the coating zone, the travel distance L3 is recorded. Then the coating area density meter continues to scan to the left. When the coating area density measured by the coating area density meter is equal to the coating area density target value σ for the first time, the coating area density meter is scanned to the left. T When the travel distance L4 is recorded, the width of the thinned area on the left and right sides of the electrode coating area is calculated. See formula (4) and formula (5) for details: L L =L2-L1 (4); <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> R <h2 style=";text-align:left;direction:ltr"> (L4-L3 (5)) In formulas (4) and (5), L L is the width of the left thinning area, L R is the width of the thinning area on the right.

3. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 2, characterized in that: The coating surface density meter is connected to the controller, which receives the surface density data and stroke data collected by the coating surface density meter, and calculates the thinning amount and thinning width of the thinning areas on the left and right sides of the electrode coating area in combination with the volume density x.

4. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 1, characterized in that: The test piece is taken from the non-thinned area of ​​the electrode coating area.

5. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 1, characterized in that: The test piece is a circular hole electrode piece punched in the coating area using a knife die or a punch, and the cross-sectional area S of the test piece is the cutting area of ​​the knife die or the punch.

6. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 1, characterized in that: When the coating surface density meter scans the electrode from left to right or from right to left, when the surface density measured by the coating surface density meter is not less than the surface density of the foil material σ for the first time 箔材 Add the set surface density difference σ 差 When the surface density meter reaches the left or right edge of the coating area, the surface density difference σ is set. 差 is a set value. The surface density of the electrode foil area is at least lower than the surface density of the electrode coating area by the set density difference σ 差 .

7. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 3, characterized in that: The controller is connected to a display screen, and the controller sends the calculated thinning amount and thinning width of the thinning areas on the left and right sides of the pole piece to the display screen for display.

8. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 3, characterized in that: The weight m, cross-sectional area S and thickness T of the test piece, and the surface density σ of the foil 箔材 , foil thickness T 箔材 are all entered into the controller, and the controller calculates the volume density x.

9. The method for measuring the thinned area of ​​a pole piece based on a lithium battery coating surface density meter according to claim 7, characterized in that: The controller converts the surface density σ collected by the coating surface density meter into L and σ R Sent to the display screen for display, the surface density σ L is the surface density value of the thinning area on the left, σ R It is the surface density value of the thinning area on the right.

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