Pre-Charge Resistor

When the battery pack contactors are closed onto a motor and inverter there will be an inrush of current into the inverter capacitor. This very high current is at a minimum likely to age the contactors, it could permanently damage the contactors. Therefore, when we closed the contactors on the battery pack we do this … Read more

How to select EV Fuses

fuse breaking energy

The fuse selection procedure is very similar to contactor selection and complementary parameters help to select EV fuses. Fuse datasheets include breaking current-time characteristics. Some of the fuse manufacturers also provide thermal and mechanical characteristics. Thermal and Mechanical Specifications Fuses are simple busbars with melting elements inside. Therefore, the initial step is always to define … Read more

How to select EV Contactors

contactor current rating vs time

Contactor selection is an iterative process that includes consideration of system specifications as well as failure scenarios. Most of the contactor manufacturers share necessary information in datasheets. Thus, a wise approach would be making a comparison table to cover basic specifications like thermal and mechanical initially. System Specifications After pre-selection based on datasheet values, we … Read more

Contactors: The Basics

contactor schematic

Contactors are electromechanical switches. They control the connection of battery Cells to the external electrical circuit. A contactor has an electromagnetic circuit. It simply works like a solenoid to push moving contact [1]. Therefore, contactors have two different electrical circuits inside: one is for actuation and the other one is to carry currents during the … Read more

Fuses: The Basics

fuse schematic

The basics of fuses are protection devices that protect electrical circuits against undesired high currents. We can use passive fuses and pyro fuses in battery design. Passive Fuse Passive fuses break the circuit only as a result of high currents for a certain time. They have a weak internal structure as a melting element. During … Read more

Electrical System of Battery

The electrical design of the battery pack is associated with fundamental electrical elements. These elements are Busbars, Contactors, Fuses, pre-charge resistors, current sensors, HV (High Voltage) and LV (Low Voltage) Connectors, and wiring harnesses. Busbars are electrically conductive materials that maintain current flow from the cells to the external electrical loads. Aluminum and copper are … Read more