Sendyne awarded second patent for active cell balancing technology for large battery arrays
5 October 2012
Sendyne, a developer of semiconductor components and advanced circuits for the management of battery systems used for grid storage and EVs, was awarded a new patent for its active balancing technology. Patent number 8,269,455 was issued by the US Patent Office for a Charge Balancing System with high efficiency and the ability to provide continuous and bi-directional charge transfers among cells in a large battery array.
Currently most battery packs employ what is called “passive balancing” to equalize cell charge. Passive balancing works by dissipating the energy of cells with greater charge to harmonize 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 says, this method slows down the charging process. During battery operation “stronger” cells end up underutilized— their effective energy capacity left untapped. Finally, this method cannot correct imbalances that occur during a normal battery cycle nor account for power output differences among cells.
Sendyne’s active cell balancing method does not have these limitations. Balancing can be performed at any point in time, with or without the presence of a charger, with very small power losses. Utilizing 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 utilized, regardless of variations in capacity from one cell to the next. This reduces the need for pack overdesign.
Proper cell balancing not only increases available capacity for each discharge cycle, but also extends the lifetime of a large-scale battery pack. Effective balancing technology thus has a direct impact on the cost of battery storage.—John Milios, Sendyne’s CEO
This is the second patent issued to Sendyne for its novel charge management technologies. This patent strengthens Sendyne’s IP portfolio, which includes 5 issued patents and numerous patent applications for technologies and semiconductor circuits aimed at reducing the cost and increasing the performance of energy storage systems.
In February, Sendyne and the University of Toronto entered into a research agreement to develop systems and electronics with the goal of accelerating the adoption of large scale battery storage for Electric Vehicles (EV) and utility-scale battery packs. (Earlier post.)
That research project is intended significantly to improve the cost and performance of such systems.
Sendyne is providing its patented technology as well as access to intellectual property, development tools and scientific expertise. The University of Toronto has developed significant technology on power supplies and power management systems which will be utilized for this project.
Leading the project team is Professor Aleksandar Prodic, from the Electrical and Computer Engineering (ECE) Department of the University of Toronto and the founder of the Laboratory for Power Management and Integrated SMPS, where the development will take place. Dr. Prodic, a recipient of several IEEE awards and distinctions, is an expert in power system design.
Patent Nº 8,269,455: Charge Balancing System
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