Robert Bosch on Battery Management Systems

Automotive IQ sat down with Chrysanthos Tzivanopoulos, Lead Engineer for Hardware Development at Robert Bosch Battery Systems, and discussed the latest developments within the industry of battery management systems. Mr. Tzivanopoulos, in which projects are you currently involved?

My current project responsibilities involve the Budget, the product cost and function responsibility of our Battery Management System Hardware Platform as well as the coordination with other platform disciplines (SW, Sys., Mech.) at my company.

Currently, there are several architectural options for Battery Management Systems on the Market. What are the most important requirements that drive the BMS architecture?

The high system flexibility enabling the use of the same BMS in different product families (EV, PHEV, 48V-Systems), the low complexity, high sense accuracy, excellent robustness (operation High Voltage, Humidity, etc.), also the Functional Safety Requirements, the very good EMC Robustness and the highly competitive cost structure.

Looking at the BMS as a whole, what area is most innovation driven? And where is the most room for improvement?

Speaking about my competence area I can see following key success factors: Further simplifying communication bus between Battery Controller and Cell e.g. wireless or PLC or similar, Simplifying the applied circuitry by keeping the sense accuracy and the new cell diagnostic functions.

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Battery Management in automotive goes far beyond just managing the battery cells and keeping the pack healthy, what else must the ‘perfect’ BMS offer to foster the performance of Battery Tech?

Enabling a very good usage of the Cell Capacity and maximizing the power taken out of the cell without stress or degradation of it. Also high voltage and current sense accuracy in combination with sophisticated functional safety functions and finally, optimal cell conditioning to operate the cell in a matter to maximize the power taken out of the cell without to degradation.

Many OEMs (and potential customers) are concerned about warrantee issues when it comes to Battery Technology for EVs. From your perspective, what’s trickier to handle: mechanical design, thermal management, electrical configuration or the battery cells?

The safety, quality and robustness of the battery Pack is the most important requirement. Due to the harsh operating environment (permanent high voltage in combination with humidity, voltage/current spikes during inverter operation), extended lifetime (extended operating time due to charging), high crash requirements, extended requirements regarding reliability and robustness are applying compared to other automotive products. This makes the development in all disciplines very challenging. The transformation of the field load to design and validation requirements is a key success factor and for this a deep know how and field experience in very important.