A force measurement system for lithium-ion battery forming tab-clamp and its electromagnetic shielding design

Abstract

Consistency of the holding force upon the battery pole-piece is one of the most critical factors to impact the quality of lithium-ion battery formation. To ensure the consistency of holding force on the same batch of electrode tab-clamps, a set of clamping force measurement system is developed to improve quality control. This paper proposes a method to measure the quasi-static force with PVDF piezoelectric sensor, which convert force into electric charge signal. Since the electric charge easily runs off and its acquisition and conversation tend to be interrupted by the external electromagnetic interferences, the electromagnetic shielding designs, such as PCB shielding design in sealed metal shell that filled with helium, and anti-interference design through coating PVDF sensor with kapton tape and copper tape, have been optimized to solve the difficulty of measuring transient charge and realize the measurement of quasi static force on the tab-clamps. The impactful results after experiments also indicate excellent application for the similar system about electric charge measurement in the future.