Integral Geometry Science Co., Ltd. and Kobe University have succeeded for the first time in the world in developing a system for measuring the spatial distribution of a magnetic field and diagnosing the current density distribution in real time and non-destructively through the analysis of the "inverse problem" related to the magnetic field.It is expected that the safety of storage batteries will be dramatically improved.

 Even if the storage battery is shipped as a good product, a fire accident may occur, and it is necessary to clarify the cause and take preventive measures.The current density inside the storage battery at the time of shipment is spatially non-uniform, and the degree of the current density gradually increases due to the charging and discharging of the storage battery, and there is a risk of short circuit and ignition in the end.Therefore, there has been a demand for a technique for non-destructively and accurately measuring the current density distribution of a storage battery before shipment.

 With the technology developed this time, the current density distribution inside the storage battery is measured by measuring the spatial distribution of the magnetic field generated around when the current flows.Until now, it was possible to mathematically derive the spatial distribution of the magnetic field from the current density distribution (forward problem), but it was extremely difficult to derive the current density distribution from the spatial distribution of the magnetic field (inverse problem). I wasn't.

 It is considered that the distance between the positive and negative electrodes is infinitely small compared to the electrode size of the battery, and the three-dimensional current flowing in the storage battery is confined between the thin parallel plates.This time, we incorporated this into the basic equation of the static magnetic field of the storage battery and succeeded in solving this inverse problem analytically for the first time in the world.Furthermore, we have developed a system "FOCUS" that measures the magnetic field space distribution with a newly developed device, analyzes the inverse problem, and visualizes the current density distribution in a non-destructive manner.

 This technology can detect uneven current density even with a good storage battery.In the future, it is expected that electric vehicles will become widespread and the production of storage batteries will increase, and if XNUMX% inspection is established in the storage battery manufacturing process, it is expected to make a great contribution to improving the safety of storage batteries.

reference: [New Energy and Industrial Technology Development Organization] Developed the world's first diagnostic imaging system for current density distribution inside storage batteries

Kobe University

To an outstanding research university that shines with advanced research and fusion research

Kobe University, which is located in a port city open to the world, has 4 faculties and 10 faculties under the 15 university arts series of "humanities / human sciences", "social sciences", "natural sciences", and "life / medical sciences". It is a comprehensive university with a graduate school, one research institute and many centers. Based on the philosophy of "harmony between science and reality," we have strengths in both the humanities and science fields […]

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