Equalization requirements for series VRLA batteries
- Resource Type
- Conference
- Authors
- Krein, P.T.; West, S.; Papenfuss, C.
- Source
- Sixteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.01TH8533) Battery applications and advances Applications and Advances, 2001. The Sixteenth Annual Battery Conference on. :125-130 2001
- Subject
- Components, Circuits, Devices and Systems
Power, Energy and Industry Applications
Voltage
Circuits
Equalizers
Battery powered vehicles
Uninterruptible power systems
Vehicle driving
Diffusion processes
Acceleration
Life testing
Hydrogen
- Language
- ISSN
- 1089-8182
State-of-charge (SOC) balance is a necessary task in any high-rate series battery system. This equalization task is evaluated here through cycling and hybrid vehicle platform tests of valve-regulated lead-acid (VRLA) batteries. It is shown that when voltage matching is used as the basis for SOC equalization, voltage differences must be kept small. An upper limit of 15 mV/cell was found from the tests, although a limit of 10 mV/cell is more realistic for a practical system. A diffusion model is developed for voltage-based equalization processes. A switched-capacitor equalization approach introduced previously is shown to be a low-cost way to meet the accuracy requirements while allowing the charge diffusion process to be accelerated. The tests show that switched-capacitor equalization supports lifetime extension in series strings.