Advanced Calcium-Thionyl Chloride High-Power Battery
Abstract
In this phase we have demonstrated that Ca/SrX2 + 7 or 20% SO2-TC cells (A7 and A20 types) can deliver at RT up to 5.5Ah at low rates and 4.4Ah at 0.9 A. These cells have 10 to 80% more capacity than have commercial Li-TC and Li-SO2 wound c-size cells. The improved A7 and A20 types cells lost almost no capacity after 4-5 weeks of storage at 70 deg C. The A20 type cell generates less heat at 20 deg C under OCV conditions than equivalent Li/TC cells, having the same electrode area, i.e. it has a longer shelf life. The addition of P40 additive to SrX2 + TC + SO2 solutions decrease further the corrosion rate of calcium. The lowest corrosion rate found for solutions containing 20% SO2 + 0.3% P40. Formolation of the SrX2-TC electrolyte with 20% SO2 and 0.3% P40 (A20S type cell) found to have the following advantages: it increases shelf life, it increases load voltage and Faradaic efficiency. A preliminary specification of A20S type Ca-TC cell is enclosed. The improved shelf-life of calcium in BaX2/TC solutions as compared to CaX2/TC solutions results mainly for the difference in the solubility or reactivity of the CaO film in those two solutions. In CaX2/TC solutions the oxide dissolves leaving the calcium with a CaCl2 layer which does not provide the metal with good protection. In BaX2/TC solutions, on the native CaO layer a BaCl2+AlCl3 or Al2O3 layer is formed. This BaCl3+AlCl3+Al2O3 layer does not form when the oxide is missing from the surface. Therefore cleaned calcium in BaX2/TC solution corrodes at the same rate as does calcium in CaX2/TC solutions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 15, 1990
- Accession Number
- ADA229168
Entities
People
- Emanuel Peled