Hardware and software framework for an open battery management system in safety-critical applications

Lithium ion batteries are a common choice for many use cases, ranging from medical devices to automotive and airborne applications. Despite their widespread application, lithium ion batteries still remain an expensive, yet sensitive component within these systems. In order to maintain the operability of the battery system over its designated service life an appropriate battery management system (BMS) is required. The development of such a BMS is a challenging task, as various technological, environmental and application-specific aspects have to be considered. Especially safe and reliable operation of the battery system is an important and critical issue in this context. Besides these safety critical aspects, the BMS also includes extensive non safety related components and functions. Therefore, in order to fulfill safety-critical requirements, it is mandatory to keep the respective hardware and software components isolated. Redundancy, partitioning and the implementation of diagnostic functions at several software layers and different hardware partitions are the mechanisms for ensuring the integrity of the system. For performance and economical reasons, these techniques have to be tailored to the application. Based on a real-time operation system, a flexible and extensible strategy for a software framework with minimal code size, lean interfaces and few dependencies is introduced. The use of a dedicated BMS-Engine with a partitioned database enables the implementation of a stringent safety concept, which is discussed and demonstrated to be feasible.