Sendyne has been awarded a new patent for its active battery cell balancing technology. Patent number 8,269,455 was issued by the US Patent Office for a Charge Balancing System with the ability to provide continuous and bi-directional charge transfers among cells in a large battery array.
Most battery packs employ “passive balancing” to equalise cell charge, dissipating the energy of cells with greater charge to harmonise them with cells of lesser charge. The excess energy is dissipated as heat. This process works only during the charge cycle; no balancing occurs during discharge and idle. In addition to wasting energy, Sendyne points out that this method slows down the charging process. During battery operation ‘stronger’ cells end up underutilised – their effective energy capacity left untapped. Further, passive balancing cannot correct imbalances that occur during a normal battery cycle, nor account for power output differences among cells.
Sendyne’s active cell balancing method can be performed at any time, with or without the presence of a charger, with what it says are “very small” power losses. Using this method, ‘weak’ cells can be protected from overstressing, thus extending their life expectancy and subsequently the life expectancy for the whole pack. More of the total energy storage capacity of all cells is utilised, regardless of variations in capacity from cell to cell, reducing the need for pack ‘overdesign’.
This is the second patent issued to Sendyne for its charge management technologies. Sendyne’s IP portfolio includes five issued patents and patent applications for technologies and semiconductor circuits aimed at reducing the cost and increasing the performance of energy storage systems.