Establishing the measuring method of the change in electrode thickness, etc. during the charging and the discharging cycle of the lithium-ion batteries

October 3, 2013

Furukawa Electric developed an on site quantitatively measuring method of the changes in black lead and in silicon based electrode thickness associated with the charging and discharging cycle mode of the lithium-ion battery. By applying this method the electrode thickness change and the deformation of the current collector can be accurately captured.

This achievement will be announced in The 54th Battery Symposium in Japan held at Osaka International Convention Center (5-3-51 Nakanoshima Kita-ku Osaka) on October 7(Mon.) to 9(Wed.), 2013.

Background of the development

Due to the high energy density of the lithium-ion batteries, the demand for thinning of the current collector copper foil is growing. This is due to the possibility of further high energy density per volume by thinning the copper foil. Upon the thinning of copper foil, the quantitatively measuring method of the electrode thickness to measure the expansion and the shrinkage of the electrode during charging and discharging is required, because of the importance of the mechanical property to withstand the stress caused by the expansion and the shrinkage of the active materials in charging and discharging.

The company established the measuring method of the negative electrode thickness during multiple cycles of charging and discharging. The method measures the expansion and the shrinkage of the electrode, which contains active materials, as height information. Using the silicon-based electrode having a large volume change (conventional foil used), in the early stage of the charging and the discharging cycles, the on site measuring of the electrode, for expansion and abnormal thickness change caused by the foil deformation, was performed. When electrode was checked at dismantling; we confirmed that the electrode condition had no discrepancy with the measurement result.

By using this method, the relation between electrode thickness change, the deformation of the electric collector and the copper foil strength can be quantitatively measured. In order to provide the best collector for a variety of active material for the current generation to the next generation, the company will enhance the battery evaluation technology as a leading company in the current collector (copper foil) provider for the lithium-ion battery.