Gao Zhengxian, Jia Xiaoqing, Wang Jin, Zhou Zhijun, Wang Jianyong, Wei Dongshan, Tu Xuecou, Kang Lin, Chen Jian, Chen Dengzhi, Wu Peiheng
Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing 210023, China.
Kexin Communication Technologies Co., Ltd., Shenzhen 518116, China.
Sensors (Basel). 2025 Jun 23;25(13):3917. doi: 10.3390/s25133917.
Precision thickness control in new energy electrode coatings is a critical determinant of battery performance characteristics. This study presents a non-destructive inspection methodology employing terahertz time-domain spectroscopy (THz-TDS) to achieve high-precision coating thickness measurement in lithium iron phosphate (LFP) battery manufacturing. Industrial THz-TDS systems mostly adopt fixed threshold filtering or Fourier filtering, making it disssssfficult to balance noise suppression and signal fidelity. The developed approach integrates three key technological advancements. Firstly, the refractive index of the material is determined through multi-peak amplitude analysis, achieving an error rate control within 1%. Secondly, a hybrid signal processing algorithm is applied, combining an optimized Savitzky-Golay filter for high-frequency noise suppression with an enhanced sinc function wavelet threshold technique for signal fidelity improvement. Thirdly, the time-of-flight method enables real-time online measurement of coating thickness under atmospheric conditions. Experimental validation demonstrates effective thickness measurement across a 35-425 μm range, achieving a 17.62% range extension and a 2.13% improvement in accuracy compared to conventional non-filtered methods. The integrated system offers a robust quality control solution for next-generation battery production lines.
新能源电极涂层中的精确厚度控制是电池性能特征的关键决定因素。本研究提出了一种采用太赫兹时域光谱（THz-TDS）的无损检测方法，以在磷酸铁锂（LFP）电池制造中实现高精度涂层厚度测量。工业太赫兹时域光谱系统大多采用固定阈值滤波或傅里叶滤波，难以平衡噪声抑制和信号保真度。所开发的方法集成了三项关键技术进步。首先，通过多峰幅度分析确定材料的折射率，将误差率控制在1%以内。其次，应用了一种混合信号处理算法，将用于抑制高频噪声的优化Savitzky-Golay滤波器与用于提高信号保真度的增强型sinc函数小波阈值技术相结合。第三，飞行时间方法能够在大气条件下实时在线测量涂层厚度。实验验证表明，在35 - 425μm范围内能够有效测量厚度，与传统未滤波方法相比，测量范围扩展了17.62%，精度提高了2.13%。该集成系统为下一代电池生产线提供了强大的质量控制解决方案。
