Battery Management System and its Applications

10 Charge Control

10.1 Introduction

The huge demand placed on a rechargeable battery creates a need for efficient battery chargers. An objective of a battery charger is to put the energy into the battery by forcing current through. The charging process should not damage or affect the battery’s capabilities. A battery charger should be efficient in order to minimize any loss of energy during the charging, should be reliable to help the battery charge when needed, and should have a high-power density to avoid a longer charging time [1]. In addition, a charger should be of low cost and portable with a lower volume and weight. Designers and manufacturers are trying hard to make a universal charger that can serve all of these items; however, it is hard to achieve a compact design with all the necessary features. The charger operation depends on the components used, switching strategies, and its controller design. Chargers also depend on the size and type of the battery being charged. The control design includes the charging algorithms. These define the charging steps by combining current, voltage, and pulse charging methods with termination conditions at various levels.

A simple battery charger is either a current source or a voltage source that can charge the battery with more tolerance to over-charging. Over-charging is when the battery continues to receive current even after being fully charged – in most battery chemistries, over-charging damages the battery components. Simple ...