In most cases, there will be a minimum of two main relays that connect the battery cell stack to the pack’s main positive and negative output terminals, those supplying high current to the electrical drive motor.
The battery pack will also have a main voltage sensor, for monitoring the voltage of the entire stack and a series of temperature sensors, such as thermistors, located at key measurement points inside the pack. Collection of data from the pack sensors and activation of the pack relays are accomplished by the pack’s battery management system (BMS).
The massive electrification efforts happening in the automotive industry are driving the need to reduce the complexity of BMS by adding electronics in the junction box, while enhancing system safety. A pack monitor can locally measure the voltages before and after the relays, the current through the battery pack.
As lithium-ion cells are inherently unsafe if they are not operated in the specified range, the BMS monitors quantities such as the cell terminal voltage, battery pack current, and temperatures and eventually disconnects the battery system from the vehicle to prevent dangerous failures such as deep-discharging or overcharging.
The main target of the battery pack design is to reduce the costs of the individual components and increase the energy density on a system level without affecting the safety and lifetime. 10.1. Introduction
Three battery packs were integrated as one string to deliver energy at different levels using a small induction motor used as load. Results of test were the veri cation of energy delivered, instrument adjustment and software control operation. Lastly, the majority of the packaging space was at the rear of the bus, due to the low- oor design.