This paper focus on the prevention and risk management of DC arcs in batteries. Indeed some commercial Liion batteries include Positive Temperature Coefficient (PTC) and Current Interrupt Device (CID) to manage safety concerns. PTC is used to prevent too high currents inside the cell. CID is used to manage cell over-charge by opening the cell circuitry by internal pressure increase. Analysis will be used to improve the Li-ion batteries safety in high voltage applications. The experimental test bench is composed of a 48 V DC battery pack and a variable resistor which can deliver a continuous current up to 1000 A. Two configurations are considered to initiate the arc. In the first configuration, the CID opens dynamically by contact release. The second configuration consists in igniting an arc between the electrodes with a copper wire in a confined space. Arc voltage and current are measured. Arc image is recorded using a high speed video camera which allows an analysis of the physical phenomena. Arcing analysis leads to solution proposal to reduce arcing risk.

International audienceWith the Gibbs free energy method, we determine the molar fraction in a plasma at and out of thermal equilibrium consisting of air and aluminum for several percentages in the temperature range of 500–6000 K. We take three temperatures into account (Trot = Th; Tvib; Tex = Te). We indicate the formulae and the numerical method used to perform the calculation taking three condensed phases AlN, Al, Al2O3 into account. We show that the air percentage plays a major role to create these phases. We clarify the role plays on the vaporization temperatures and on the sublimation temperatureby the non-thermal equilibrium of the plasma. This kind of plasma is found in arc roots, near a wall, in plasmas with a high value of electrical field,… The influence of the pressures until 30 9 105 Pa. is shown on molar fraction of the chemical species, on the vaporization temperatures and on the sublimation temperature. The vaporization temperatures are given versus the thermal non equilibrium versus various mixtures (air, aluminum) and versus the pressures (10^5 Pa–30 10^5 Pa)

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