The market breakthrough of electric vehicles is mainly delayed by the still too high costs of the battery system. The novel distributed battery cell monitoring and management concept presented in this paper allows a significant reduction of the final battery pack costs. Further, due to economies of scale, it provides reduced development costs and much lower time-to-market. The proposed concept provides a contactless cost-efficient data transmission interface with capacitive coupling, thus making the development of a battery monitoring circuit for each battery module type needless. The costs are mainly reduced thanks to the high volume manufacturing approach of novel smart battery cells integrating all the sensors of the monitoring electronics together with passive cell balancing and cell heating function. This paper describes the possibilities offered by the proposed concept and shows implementation examples of such a contactless distributed battery cell monitoring

The market breakthrough of electric vehicles is mainly delayed by the still too high costs of the battery system. The smart battery cell monitoring presented in this article enables further cost reduction. It consists of battery cells integrating the monitoring electronics together with a data transfer interface for communicating in a bidirectional way with the battery management system. The data transfer interface presented in this paper is based on a differential contactless data transmission bus using galvanically isolated capacitive coupled links to each single smart battery cell. Since neither galvanic contacts nor connectors are needed, the proposed concept provides simultaneously a very high level of reliability and robustness, and a highly cost-efficient manufacturing process, thus allowing a significant reduction of the final battery pack costs. This paper describes a possible implementation of such a differential contactless data transmission for monitoring and managing battery cells in electric vehicles. State-of-the-Art in Battery SystemsDespite the great efforts that have been made during the last years to promote electric mobility, the electrical vehicle still has not had its final breakthrough. An important reason for the lack of broad acceptance is the cost of electric vehicles (EV) that is still too high. Especially the battery system is and will remain a major cost factor in the near future. This article describes a novel approach to the battery system, which is aimed to significantly reduce the component costs, the development time and the manufacturing costs of the battery system, while increasing its flexibility and reliability.

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

The various application scenarios of a battery system lead to versatile, often conflicting requirements for hardware, software and mechanical design. The intended use of a lithium-ion battery system in mobile and stationary applications determines a lot of restrictions such as design space and ambient conditions. Additional hardware and software requirements are dictated by engineering constraints like the safe operating area for a specific battery cell. This paper presents a flexible and extensible battery management system (BMS) for lithium-ion battery packages, which aims at addressing these issues. The flexible approach in the software architecture is therefore mandatory. The structure of the embedded hardware platform is introduced, and its modular setup is presented. An easy-to-use, yet powerful framework for building the software and its documentation is shown. With a view to being useful to a large community of developers and users, the hardware design and the software will be open-source and freely available. As a result, the presented BMS serves as an easy-to-use platform for academia research and as a development platform for industrial users