Cell-BMS validation with a hardware-in-the-loop simulation of lithium-ion battery cells for electric vehicles

• We propose a HIL simulation of Li-ion cells for the validation of cell-BMS.
• Battery behavior is emulated by the equivalent circuit model.
• The parameters of the model can be configured according to different conditions.
• The emulated outputs are bidirectional, power-amplified and can be serially connected.
• It can validate functions of voltage detection, cell balancing and fault diagnosis.

Battery management system (BMS) plays a critical role in the development of hybrid electric vehicles (HEVs), plug-in hybrid vehicles (PHEVs) and battery electric vehicles (BEVs). The cell-BMS is the lower-level part of the BMS, which generally takes care of the individual cells directly, with functions mainly including voltage detection and cell balancing. In this paper, a configurable battery cell emulating system is developed to implement the hardware-in-the-loop (HIL) validation of the cell-BMS. The battery cell dynamics is simulated with a parameter-configurable equivalent circuit model consisting of three resistors, two capacitors and a SOC-controlled voltage source. The HIL system emulates battery cell dynamics to validate the function of voltage monitoring. With the bi-directional and power-amplified outputs, the system can also evaluate the performance of both active and passive cell balancing module. Meanwhile the emulated cells can be connected in series, and can be adapted to simulate some faults, e.g., over-charge and over-discharge as well. Initial testing cases using a cell-BMS prototype for the LiMnO2 based battery cells show a good performance of the system. The system standardizes function validation of the cell-BMS before the design finalization and thereby accelerates the BMS development and reduces the development costs.