Current and heat balancing constant voltage charging

Abstract

A constant voltage may be used during battery charging to reduce or avoid the formation of a dendrite, such as a stepped constant voltage. For each charging period, each level of the stepped constant voltage may be calculated to ensure a corresponding current level within each period remains below a safe current limit. A voltage transition between any two periods may occur in response to expiration of a predetermined time, or in response to a determination that the current level has fallen below a lower current limit. A current level during each period may be maintained such that the battery heat is maintained below a reference heat level, which may increase battery cycle life (e.g., battery capacity or maximum recharging cycles). The battery heat may be measured directly or indirectly, or may be estimated based on other measured or controlled values.