How to detect the thickness of lithium ion battery separator?

How to detect the thickness of lithium ion battery separator? 1. A single X-ray ensures the accuracy of the online diaphragm thickness detection. The principle of online diaphragm thickness detection is to convert the attenuation of the ray through the diaphragm into the thickness of the diaphragm. This means that the accuracy and stability of the detection must be ensured during the detection process. The accuracy and stability of detection are ensured by the sensor constant temperature control technology and internal standard sample technology. Among them, the internal standard technology can be calibrated automatically and regularly to ensure the stability of the sensor, thereby eliminating the influence of dust in the air, especially when measuring ceramic coatings, ceramic powder will fall off. During the inspection process, due to the very low thickness of the ceramic coating, the accuracy of the measurement has been questioned by those in the industry. A single X-ray is used to detect the thickness of the ceramic coating. The base film is 20μ, the ceramic coating amount is 2μ and 4μ data for X-ray analysis: No-load data I0u003d54272, 20μm base film measurement data Ibu003d53383, 20μm+2μm (coating) measurement data Ir u003d51590 The measured data of 20μm+4μm (coating) is 49829. The corresponding base film calculated by the formula is 20.017μ, the sensitivity K value is 1212, the value of the ceramic coating amount is 2.008, and its K value is 58.8; the value corresponding to the ceramic coating amount of 4μ is 4.051, the K value The same is 58.8. This illustrates a problem well. The attenuation of the ceramic coating is much greater than that of the original film. The sensitivity difference between the two is about 20 times, so the data measured by X-ray after coating mainly reflects the thickness of the ceramic coating, and the attenuation of the base film is negligible compared to the ceramic. Tested with other types of diaphragms, corresponding to the original film of 20μ, the thickness changes are all within 3μ. Through calculation and actual measurement, corresponding to the change of the original film thickness of 3μ, the display error of X-ray thickness measurement is plus or minus 0.08μ. That is to say, X-ray is used to detect the ceramic-coated diaphragm. When the base film changes at 3μ, the error of the ceramic coating detection is only within plus or minus 0.08μ, and this error is completely negligible. 2. On-line control technology of diaphragm thickness. There are two important on-line control technologies for diaphragm thickness, one is MD (longitudinal) control and CD (transverse) control; the other is diaphragm online machine vision inspection technology. 1) MD control and CD control The so-called MD control and CD control refer to the closed-loop control of the thickness in the MD direction by controlling the speed of the feeding screw or the traction speed; and the data measurement through the scanning frame, and finally the closed-loop control of the data in the CD direction. . The key technology is the CD banner alignment technology, that is, the inspection data of the scanning frame must be accurately aligned with the position of the full-width die. In addition, the shrinkage factor of the film must be considered. Only the alignment can be controlled. Great. 2) Diaphragm online machine vision detection technology. Some people may think that the missing coating and black spots on the diaphragm can be detected through the camera, but the image processing board can not only detect, but also perform intelligent analysis. It is understood that the key to the diaphragm is the identification of pinholes. The pinhole recognition technology is introduced for diaphragm detection, which is a technology that distinguishes pinholes and bright spots through multiple imaging exposures. In addition to pinhole recognition, it also has other intelligent classification functions, that is, intelligent classification algorithms. Through intelligent classification, comprehensive defect analysis data can be provided to help the company improve equipment and processes, and improve product quality. As one of the four main materials, the diaphragm, although its composition is relatively simple, but there are still more items tested. With the development of technology, ceramic diaphragms have been widely used, such as glued diaphragms and functional coated diaphragms. New types of separators such as, non-woven separators have also been gradually applied to lithium-ion batteries. It is believed that in the near future, more high-safety and high-mechanical separators will gradually enter the lithium-ion battery industry. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete.