A Bi-level Equalizer for Battery Cell Charge Management


Project ID: D2016-41


Invention Description and Novelty:

This technology can provide a large increase in the capacity of older lithium ion batteries (LIB) that consist of cells connected in series or series/parallel. These LIBs require a battery management system (BMS) which measures and equalizes (EQU) the cell voltages to maximize performance and protect the cells from damage. Most applications use cheap resistive EQUs (REQs) that are inefficient and do little to increase battery capacity.  Switching EQUs (SEQs) are much more efficient and can maximize battery capacity, but they are very expensive. Our new hybrid EQU, called the bi-level EQU (BEQ), provides performance close to an SEQ, but at a modest cost that is comparable to an REQ.



Electric/Hybrid Vehicles (EVs), Military/Aerospace, and Energy Storage (ES) for Grid Connected Solar and Wind Energy


Value proposition:

Novel system provides advantages including:

1.       Primary asset of our new BMS is that it contains a cell voltage equalizer (EQU) that is much more effective in terms of performance and cost than anything in the present market.

2.       Compared to REQ, our BEQ increases lifetime battery capacity and range of an EV by 50% at a cost increase of only $33 per unit. For a 10 year battery, this effectively adds an additional five years to its life.

3.       Estimated cost in the range of an REQ, but provides about 98% efficiency (as opposed to 0% for an REQ) and a much higher battery capacity that is close to that of an SEQ. 

4.       Both BEQ and SEQ provide a capacity that is about 50% higher than the cheaper but widely used REQ, but the BEQ cost is only about 45 % of an SEQ.

5.       Preliminary lab prototype has been designed and tested, and test results confirm improved performance


IP Status: Provisional patent application # 62/287,575


Patent Information:
For Information, Contact:
Katherine Pollard
Licensing Associate
The University of Toledo
Thomas Stuart
Thomas Stuart
Electric/Hybrid Vehicles
Energy Storage