How much do you know about hybrid vehicle battery systems?

Study Notes

The Electrical Distribution System (EDS) provides electrical conduction and has several features, including isolation, current and voltage measurement, pre-charge function, fusing, manual disconnect, and insulation monitoring.
The low-voltage wiring powers battery control functions and communication between the battery and vehicle.
Isolation testing is necessary to ensure the high-voltage system is completely isolated from the vehicle.
State-of-charge management is crucial to prevent overheating and maximize battery service life.
The HV battery pack controller monitors state-of-charge, and the normal operating range is within 52-68%.
Scan data test procedures can be used to check battery state-of-charge and internal resistance.
Defective high-voltage battery components can be replaced instead of the entire battery to reduce repair time and cost.
Battery modules can be replaced, and internal resistance should be matched as closely as possible.
Connecting batteries in series requires close voltage matching, and a diagnostic trouble code may occur if there is a voltage difference.
Factors affecting battery life and degradation include energy storage decline, liquid-cooled vs. air-cooled batteries, and vehicle use.
Hot temperatures lead to faster decline in battery health
DC fast-chargers speed up degradation, especially in hot climates
Passive and active cell balancing are necessary for long battery life
Passive balancing dissipates energy from most charged cell as heat
Active balancing transfers energy from most charged cell to least charged cells
Battery management system (BMS) monitors battery during normal operation
BMS calculates SOC and determines charging rate
Dealerships may have special chargers for HEV battery packs
Best charger for HEV battery is the vehicle itself
Follow manufacturer's specified procedures when starting a disabled hybrid vehicle.