A novel technology which can recycle spent batteries to double their cycle-life is being developed in Germany.
The breakthrough — applying a multilayer coating to the battery’s electrodes— is set to improve the functional properties and the cycle life of lead-acid batteries by 50%.
Professor Hans Warlimont is working with his R&D partner OTA Oberflächentechnik Anlagenbau in Berlin to bring the process to market.
The new technology creates battery grids in multiple thin layers of pure binary Pb-Sn alloys at two levels of Sn-content to increase corrosion resistance and to reduce grid growth and shedding of the active mass.
Scrap and even the active material of spent batteries can be used as raw material for the galvanic production of composite battery grids.
Various kinds of scrap and active material have been studied to prove that the deposits satisfy the impurity limits of battery grade material.
The system has been tested by battery companies, including Moll and China’s Shandong Sacred Sun Power Sources Industry, using conventional and composite grids in different combinations for the positive and negative battery plates.
Tests included comparing the cycling behaviour of electroformed multilayer composite grids against gravity cast, bulk and structured grids.
Warlimont said: “Despite some early failures these test grids exceeded average life of 190 cycles of the conventional cast grids by about 50%.”
He added: “The composite battery grids and the galvanic process for their production have been developed to a mature technology.
“The multi-layered composite grids impart superior grid properties compared to present day grids.
“In particular, the use of a Cu layer to decrease the resistivity improves the electrical properties and the performance parameters significantly.”