US Patent 10446879 Battery condition determination

An energy conversion arrangement configured to convert chemical energy into electrical energy. The energy conversion arrangement comprises plural cell groups (30, 32, 34, 36), each cell group being configured to convert chemical energy into electrical energy. The energy conversion arrangement also comprises at least one measurement arrangement (38,40,42,44,46) configured to make measurements at each of the plural cell groups (30, 32, 34, 36). Each energy conversion arrangement is configured to determine a condition of at least one of: each of the plural cell groups; and the energy conversion arrangement. The condition is determined in dependence on the measurements made at each cell group and a model of each cell group.