The use of a high-Tc (HTS) rf-superconducting quantum interference device (SQUID) for inspecting the liquid component of lithium-ion (Li-ion) batteries is proposed. It is possible that a small amount of metal can become mixed in with components of Li-ion batteries during the manufacturing process and contaminate them, with a resultant fire risk, Thus, the development of a highly sensitive inspection system is required. In this article we describe a test system, we developed using a single channel HTS rf-SQUID consisting of a cryostat, a polyethylene tube, and a permanent magnet. The SQUID needs to be installed as close to the battery liquid as possible to obtain more sensitive readings. Therefore, we designed a microscope-type SQUID cryostat in which the SQUID can approach the target as close as 1 mm. In the system, the liquid was not flowed through the polyethylene tube, but a small metallic sample stack on a fishing line was moved by a motor. A stainless steel cut wire with a nominal size of φ 50 μm was prepared. After magnetizing the sample, the stray magnetic field of the sample was measured by the SQUID. The peak-to-peak signal scaled inversely with the cube of the stand-off distance. It was found that a signal of the sample with φ 50 μm at a distance of 26 mm could be detected if the signal-to-noise ratio (SNR) > 3 was supposed as the threshold of the inspection. The dependence on the sample size was also investigated, using stainless steel samples with different sizes (φ 50–φ 160 μm). The peak-to-peak signal scaled with the cube of the diameter.

中文翻译：

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使用High-Tc rf SQUID开发用于锂离子电池液体组件的金属污染物检测系统

建议使用高 Tc (HTS) 射频超导量子干涉装置 (SQUID) 来检查锂离子 (Li-ion) 电池的液体成分。在制造过程中，少量金属可能会混入锂离子电池的组件中并污染它们，从而导致火灾风险，因此需要开发高度灵敏的检测系统。在本文中，我们描述了一个测试系统，我们使用由低温恒温器、聚乙烯管和永磁体组成的单通道 HTS rf-SQUID 开发。SQUID 需要安装在尽可能靠近电池液体的位置，以获得更灵敏的读数。因此，我们设计了一种显微镜式 SQUID 低温恒温器，其中 SQUID 可以接近目标 1 毫米。在系统中，液体没有流过聚乙烯管，而是由马达移动了钓鱼线上的小金属样品堆。准备了标称尺寸为φ50μm的不锈钢切割丝。样品磁化后，通过SQUID测量样品的杂散磁场。峰峰值信号与间隔距离的立方成反比。发现如果将信噪比（SNR）> 3作为检查阈值，则可以检测到距离为26 mm的φ 50 μm样品的信号。还使用不同尺寸（φ 50-φ 160 μm）的不锈钢样品研究了对样品尺寸的依赖性。峰峰值信号与直径的立方成比例。准备了标称尺寸为φ50μm的不锈钢切割丝。样品磁化后，通过SQUID测量样品的杂散磁场。峰峰值信号与间隔距离的立方成反比。发现如果将信噪比（SNR）> 3作为检查阈值，则可以检测到距离为26 mm的φ 50 μm样品的信号。还使用不同尺寸（φ 50-φ 160 μm）的不锈钢样品研究了对样品尺寸的依赖性。峰峰值信号与直径的立方成比例。准备了标称尺寸为φ50μm的不锈钢切割丝。样品磁化后，通过SQUID测量样品的杂散磁场。峰峰值信号与间隔距离的立方成反比。发现如果将信噪比（SNR）> 3作为检查阈值，则可以检测到距离为26 mm的φ 50 μm样品的信号。还使用不同尺寸（φ 50-φ 160 μm）的不锈钢样品研究了对样品尺寸的依赖性。峰峰值信号与直径的立方成比例。峰峰值信号与间隔距离的立方成反比。发现如果将信噪比（SNR）> 3作为检查阈值，则可以检测到距离为26 mm的φ 50 μm样品的信号。还使用不同尺寸（φ 50-φ 160 μm）的不锈钢样品研究了对样品尺寸的依赖性。峰峰值信号与直径的立方成比例。峰峰值信号与间隔距离的立方成反比。发现如果将信噪比（SNR）> 3作为检查阈值，则可以检测到距离为26 mm的φ 50 μm样品的信号。还使用不同尺寸（φ 50-φ 160 μm）的不锈钢样品研究了对样品尺寸的依赖性。峰峰值信号与直径的立方成比例。