Battery sealing force measurement method

Abstract

The application discloses a battery sealing force calculation method, which has the advantages of easy obtaining one-sealing, two-sealing and three-sealing pressure, shorter time consumption and simple operation. The battery sealing force calculation method comprises the following steps: performing one-sealing preliminary necking, so that the edge compression angle of the open end of the battery is in the range of 10-30°, the compression amount of the first structure part and the second structure part is all less than or equal to 10%, and one-sealing pressure F1 is obtained after confirmation; performing two-sealing further necking, so that the edge compression angle of the open end of the battery is in the range of 40-60°, the compression amount of the first structure part and the second structure part is in the range of 20-30%, and two-sealing pressure F2 is obtained after confirmation; completing three-sealing edge buckling necking, so that the edge buckling angle of the open end of the battery is in the range of 12-22°, the compression amount of the first structure part and the second structure part is in the range of 30-60%, and three-sealing pressure F3 is obtained after confirmation; and one-sealing, two-sealing and three-sealing pressure of the battery are F1, F2 and F3 respectively.

Description

Technical Field

[0001] This invention relates to the field of battery manufacturing, and more particularly to a method for calculating battery sealing force. Background Technology

[0002] The manufacturing process of lithium-ion cylindrical batteries involves mechanical sealing, which involves tightly fitting the cap and steel casing together, compressing the casing opening and sealing ring to seal the cell and protect against thermal runaway. The mechanical sealing process includes first, second, and third sealing. However, during these processes, it's impossible to monitor the internal structural deformation in real time, making it difficult to determine if the sealing pressure and battery structural deformation meet requirements, thus hindering pressure adjustment. Excessive compression of the sealing ring can cause deformation of the cap's metal components, affecting thermal runaway protection and potentially causing insulation failure. Conversely, insufficient compression can lead to leakage. After sealing the battery using these methods, multiple tests are required to verify compliance. If non-compliance is found, the first, second, and third sealing pressures need to be reviewed to identify issues affecting sealing quality. However, this process is time-consuming, complex, and lacks standards, making it difficult to efficiently identify factors affecting sealing quality.

[0003] Therefore, there is an urgent need for a battery sealing force calculation method that is easy to obtain the pressure of the first, second, and third seals, and is quick and easy to operate, in order to overcome the above-mentioned shortcomings. Summary of the Invention

[0004] The purpose of this invention is to provide a method for calculating battery sealing force that is easy to obtain the pressure of the first, second, and third seals, takes less time, and is simple to operate.

[0005] To achieve the above objectives, this invention discloses a method for calculating battery sealing force, used to calculate the forces acting during the battery sealing process, including first sealing pressure, second sealing pressure, and third sealing pressure. The battery includes a casing, a cap, and a sealing ring. The cap is installed at the opening of the casing, and the sealing ring is disposed between the cap and the casing. The casing forms a neck extending circumferentially outward near its opening. The sealing ring includes a first structural portion disposed between the edge of the cap and the neck, and a second structural portion adjacent to the opening end of the casing. The battery sealing force calculation method includes the following steps:

[0006] Step 1: Perform a preliminary shrinkage to ensure that the pressing angle of the opening end of the battery is within the range of 10-30°, and that the compression amount of both the first structural part and the second structural part is ≤10%. After confirmation, the sealing pressure F1 is obtained.

[0007] Step 2: Perform a second seal to further reduce the opening, so that the pressing angle of the battery opening end is within the range of 40-60°, and the compression amount of the first structural part and the second structural part is within the range of 20%-30%. After confirmation, the second seal pressure F2 is obtained.

[0008] Step 3: Complete the three-seal edge reduction, so that the edge angle of the battery opening is within the range of 12-22°, and the compression of the first structural part and the second structural part is within 30%-60%. After confirmation, the three-seal pressure F3 is obtained.

[0009] Step 4: Obtain the first, second, and third seal pressures of the battery as F1, F2, and F3, respectively.

[0010] Preferably, after initial sealing and shrinking, the pressing angle of the opening end of the battery is in the range of 20-30°, and the compression amount of the first structural part and the second structural part is ≤5%.

[0011] Preferably, after a second sealing process to further reduce the opening, the pressing angle of the open end of the battery is within the range of 50-60°.

[0012] Preferably, after completing the three-seal shrinkage, the compression of the first structural part and the second structural part is within the range of 35%-50%.

[0013] Preferably, after sealing, the battery is half-cut, the pressing angle of the open end of the battery is calculated, and the compression amount of the first structural part and the second structural part is calculated.

[0014] Preferably, after the second sealing, the battery is cut in half, the pressing angle of the open end of the battery is calculated, and the compression amount of the first structural part and the second structural part is calculated.

[0015] Preferably, after completing the three-seal process, the battery is cut in half, the angle of the snap edge at the open end of the battery is calculated, and the compression of the first structural part and the second structural part is calculated.

[0016] Preferably, after the battery is cut in half, the state of the cut surface is observed and various data are calculated using an electron microscope.

[0017] Preferably, the cap includes a top cap and a bottom cap, the edge of the bottom cap wraps around a portion of the edge of the top cap, and after the three-sealed edge is closed, the parallelism between the exposed portion of the edge of the top cap and the bottom of the bottom cap is also measured.

[0018] Preferably, the initial narrowing, the second narrowing, and the third sealing are achieved by applying pressure to the open end of the shell.

[0019] Compared with existing technologies, the battery sealing force calculation method of this invention, by limiting the parameters after the first, second, and third seals, ensures tight contact between the sealing ring and the inner wall of the casing, guaranteeing the airtightness of the sealing ring and ensuring that the deformation of the cap meets the regulations. Under this premise, the obtained first-seal pressure F1, second-seal pressure F2, and third-seal pressure F3 are based on the compliance of the sealing ring and the cap. Therefore, when using the first-seal pressure F1, second-seal pressure F2, and third-seal pressure F3 to produce batteries, it is guaranteed that the products leaving the factory meet production requirements. Moreover, the entire process is guided by a standard. With the standard followed, it is easy to obtain the first, second, and third seal pressures, saving the time required for the entire process and making the operation simpler. Attached Figure Description

[0020] Figure 1 This is a flowchart of the battery sealing force calculation method of the present invention for calculating the forces acting during the battery sealing process.

[0021] Figure 2 This is a normal distribution diagram of the bonding gap data of three batteries, 18650, 21700, and 32140, after applying the battery sealing force calculation method of this invention and applying other existing methods for sealing.

[0022] Figure 3 This is a normal distribution diagram of the parallelism of the caps after three batteries (18650, 21700, and 32140) were sealed using the battery sealing force calculation method of this invention and other existing methods. Detailed Implementation

[0023] To illustrate the technical content and structural features of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0024] like Figure 1 As shown, this invention discloses a method for calculating battery sealing force, used to calculate the forces acting during the battery sealing process, including first sealing pressure, second sealing pressure, and third sealing pressure.

[0025] The battery 10 includes a housing 11, a cap 12, and a sealing ring 13. The cap 12 is installed at the opening of the housing 11, and the sealing ring 13 is disposed between the cap 12 and the housing 11. The housing 11 forms a neck 14 extending outward in a circumferential direction near its opening. The sealing ring 13 includes a first structural portion 15 disposed between the edge of the cap 12 and the neck 14, and the sealing ring 13 also includes a second structural portion 16 adjacent to the opening end of the housing 11.

[0026] The battery sealing force calculation method of the present invention includes the following steps:

[0027] Step 1: Perform a preliminary sealing process, ensuring the pressing angle of the open end of the battery 10 is within the range of 10-30°, and that the compression amount of both the first structural part 15 and the second structural part 16 is ≤10%. The purpose is to ensure that the sealing ring 13 deforms during the sealing operation before the second sealing, thus tightly adhering to the inner wall of the housing 11 and guaranteeing that the sealing gap meets the specifications. After confirmation, the sealing pressure F1 is obtained.

[0028] Step 2: Perform a second sealing process to further reduce the opening, ensuring the pressing angle of the open end of battery 10 is within the range of 40-60°, and the compression of the first structural part 15 and the second structural part 16 is within the range of 20%-30%. The purpose is to ensure that the sealing ring 13, before the third sealing, deforms with the second sealing and fits tightly against the inner wall of the housing 11, guaranteeing that the second sealing gap meets the specifications. After confirmation, the second sealing pressure F2 is obtained.

[0029] Step 3: Complete the triple-seal edge reduction, ensuring the edge angle of the open end of battery 10 is between 12-22°, and the compression of the first structural part 15 and the second structural part 16 is between 30%-60%. This ensures optimal resilience of the sealing ring 13 and compliance with airtightness and metallic deformation requirements of the cap 12. Compression of the sealing ring 13 <30% may result in incomplete sealing leading to air or liquid leakage, while compression >60% may lead to plastic deformation of the sealing ring 13 causing airtightness failure, and deformation of the cap 12 leading to thermal runaway failure. After confirmation, the triple-seal pressure F3 is obtained.

[0030] Step 4: Obtain the first, second, and third sealing pressures of this battery 10 as F1, F2, and F3, respectively.

[0031] Using the battery sealing force calculation method of this invention, by limiting the parameters after the first, second, and third seals, it ensures that the sealing ring 13 is in close contact with the inner wall of the housing 11, guaranteeing the airtightness of the sealing ring 13 and ensuring that the deformation of the cap 12 meets the requirements. Under this premise, the obtained first-seal pressure F1, second-seal pressure F2, and third-seal pressure F3 are based on the compliance of the sealing ring 13 and the cap 12. Therefore, when using the first-seal pressure F1, second-seal pressure F2, and third-seal pressure F3 to produce batteries, it is guaranteed that the products leaving the factory meet the production requirements. Moreover, the entire process is guided by a standard. With the standard followed, it is easy to obtain the first, second, and third seal pressures, saving the time required for the entire process and making the operation simpler.

[0032] Furthermore, after initial shrinkage, the pressing angle of the open end of the battery 10 is kept within the range of 20-30°, and the compression of the first structural part 15 and the second structural part 16 is kept ≤5%, ensuring that the sealing ring 13 is tightly attached to the inner wall of the housing 11 before the second sealing. After further shrinkage during the second sealing, the pressing angle of the open end of the battery 10 is kept within the range of 50-60°, ensuring that the sealing ring 13 is tightly attached to the inner wall of the housing 11 before the third sealing. After the third sealing is completed, the compression of the first structural part 15 and the second structural part 16 is kept within the range of 35%-50%, ensuring that the sealing ring 13 after the third sealing will not have a loose seal or fail to seal.

[0033] like Figure 1 As shown, during operation, a sealing pressure F1 is applied to the open end of the housing 11 to perform a preliminary sealing, a second sealing pressure F2 is applied to the open end of the housing 11 to perform a second sealing to further seal, and a third sealing pressure F3 is applied to the open end of the housing 11 to perform a third sealing.

[0034] To facilitate data calculation, after the first, second, and third sealing processes, the battery 10 is cut in half, and the cross-sectional state is observed using an electron microscope to calculate various data. It is worth noting that before the sealing operation, the battery 10 can be cut in half to measure the thickness of the first structural portion 15 and the second structural portion 16 before the sealing ring 13 is compressed, using these as baseline values. Additionally, the open end of the battery 10 is in a vertical position before being bent.

[0035] After sealing, the battery 10 is partially cut, and the pressing angle A1 of the opening end of the battery 10 is calculated. The compression amount A2 of the first structural part 15 and the compression amount A3 of the second structural part 16 are also calculated. The calculated values ​​must fall within the following ranges before the current sealing pressure F1 is recorded: 20°≤A1≤30°, A2≤5%, A3≤5%.

[0036] After the second sealing is performed, the battery 10 is cut in half, and the pressing angle B1 of the opening end of the battery 10 is calculated. The compression amount B2 of the first structural part 15 and the compression amount B3 of the second structural part 16 are also calculated. The calculated values ​​must fall within the following ranges to record the current second sealing pressure F2, namely 50°≤B1≤60°, 20%≤B2≤30%, and 20%≤B3≤30%.

[0037] After completing the triple sealing, the battery 10 is cut in half. The angle C1 of the snap edge at the open end of the battery 10 is calculated. The compression amount C2 of the first structural part 15 and the compression amount C3 of the second structural part 16 are calculated. The calculated values ​​must fall within the following ranges to record the current triple sealing pressure F3, namely 12°≤C1≤22°, 35%≤C2≤50%, and 35%≤C3≤50%.

[0038] The first sealing pressure F1, second sealing pressure F2, and third sealing pressure F3 obtained by the battery sealing force calculation method of the present invention, when applied to actual production, have been found to reduce the gap between the sealing ring 13 and the housing 11.

[0039] For details, please refer to the following: Figure 2 As shown, three battery models—18650, 21700, and 32140—were used for testing. It was found that batteries produced using other existing methods had relatively large gaps between the sealing ring and the inner wall of the casing, and the data was relatively scattered. In contrast, batteries produced using the method of this invention had relatively small gaps between the sealing ring 13 and the inner wall of the casing 11, and the data was relatively concentrated. Therefore, by using the battery sealing force calculation method of this invention to measure F1, F2, and F3, and then performing one-sealing, two-sealing, and three-sealing operations using F1, F2, and F3, the resulting batteries can effectively improve the gap between the sealing ring 13 and the inner wall of the casing 11 after sealing, and effectively improve product quality stability and airtightness. More importantly, the method of this invention eliminates the need for repeated reviews of the one-sealing, two-sealing, and three-sealing processes; even if reviews are necessary, the influencing factors are easily identified. The entire process is time-efficient and simpler to operate.

[0040] In addition, the state of the cap 12 after sealing also reflects the sealing quality, with the most direct impact being the parallelism of the cap 12. For example... Figure 1 As shown, the cap 12 includes a top cap 121 and a bottom cap 122. The edge of the bottom cap 122 wraps around the edge of the top cap 121. After completing the three-sealed edge reduction, the parallelism G between the exposed portion D of the edge of the top cap 121 and the bottom E of the bottom cap 122 is measured. Figure 3 As shown, three battery models—18650, 21700, and 32140—were used in this test. It was found that batteries produced using other methods had relatively large parallelism G values, and the data was scattered and inconsistent. However, the batteries produced using this invention effectively improved the parallelism G value, and the data was more concentrated. Therefore, after obtaining F1, F2, and F3 using the battery sealing force calculation method of this invention, the batteries obtained after one, two, and three seals using F1, F2, and F3 have minimal impact on the initial state of the cap 12, effectively improving product quality stability, reducing the problem of thermal runaway protection failure, and improving product quality and safety performance.

[0041] The above-disclosed examples are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are within the scope of the present invention.

Claims

1. A method for calculating battery sealing force, used to calculate the forces acting during the battery sealing process, including first sealing pressure, second sealing pressure, and third sealing pressure. The battery includes a casing, a cap, and a sealing ring. The cap is installed at the opening of the casing, and the sealing ring is disposed between the cap and the casing. The casing forms a neck extending outward in a circumferential direction near its opening. The sealing ring includes a first structural portion disposed between the edge of the cap and the neck, and a second structural portion adjacent to the opening end of the casing. The method is characterized in that... The battery sealing force calculation method includes the following steps: Perform a preliminary shrinkage to ensure that the pressing angle of the opening end of the battery is within the range of 20-30°, and that the compression amount of both the first structural part and the second structural part is ≤5%. After confirmation, the sealing pressure F1 is obtained. After sealing, the battery is half-cut, and the pressing angle A1 of the open end of the battery is calculated. The compression amount A2 of the first structural part and the compression amount A3 of the second structural part are also calculated. The calculated values ​​must fall within the following ranges to record the current sealing pressure F1: 20°≤A1≤30°, A2≤5%, A3≤5%. A second sealing process is performed to further reduce the opening, so that the pressing angle at the opening end of the battery is within the range of 50-60°, and the compression of the first structural part and the second structural part is within the range of 20%-30%. After confirmation, the second sealing pressure F2 is obtained. After the second sealing, the battery is cut in half. The pressing angle B1 of the open end of the battery is calculated, and the compression amount B2 of the first structural part and the compression amount B3 of the second structural part are calculated. The calculated values ​​must fall within the following ranges to record the current second sealing pressure F2, namely 50°≤B1≤60°, 20%≤B2≤30%, and 20%≤B3≤30%. Complete the three-seal edge reduction, so that the edge angle of the battery opening is within the range of 12-22°, and the compression of the first structural part and the second structural part is within 35%-50%. After confirmation, the three-seal pressure F3 is obtained. After completing the triple sealing, the battery is cut in half. The angle C1 of the snap edge at the open end of the battery is calculated, and the compression amount C2 of the first structural part and the compression amount C3 of the second structural part are calculated. The calculated values ​​must fall within the following ranges to record the current triple sealing pressure F3, namely 12°≤C1≤22°, 35%≤C2≤50%, and 35%≤C3≤50%. The pressures of the first, second, and third seals of this battery are F1, F2, and F3, respectively.

2. The battery sealing force calculation method according to claim 1, characterized in that, After sealing, the battery is half-cut, the pressing angle of the open end of the battery is calculated, and the compression amount of the first and second structural parts is calculated.

3. The battery sealing force calculation method according to claim 1, characterized in that, After the second sealing, the battery is half-cut, and the pressing angle of the open end of the battery is calculated. The compression amount of the first and second structural parts is also calculated.

4. The battery sealing force calculation method according to claim 1, characterized in that, After completing the three-seal process, the battery is cut in half, and the angle of the snap edge at the open end of the battery is calculated. The compression of the first structural part and the second structural part is also calculated.

5. The battery sealing force calculation method according to claim 1, characterized in that, After the battery is cut in half, the state of the cut surface is observed and various data are calculated using an electron microscope.

6. The battery sealing force calculation method according to claim 1, characterized in that, The cap includes a top cover and a bottom cover. The edge of the bottom cover wraps around part of the edge of the top cover. After the three-sealed edge is closed, the parallelism between the exposed part of the edge of the top cover and the bottom of the bottom cover is also measured.

7. The battery sealing force calculation method according to claim 1, characterized in that, The opening of the shell is sealed by applying pressure to the opening end, which involves a preliminary shrinkage, a further shrinkage, and a final edge sealing.

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