Technician Handbook 601 Hybrid Systems for Collision Repair HV Battery The Hybrid Vehicle (HV) battery powers the vehicle’s high-voltage systems. There are two kinds of HV batteries: • Nickel Metal Hydride (NiMH) batteries, which are used on most hybrid vehicles • Lithium-ion (Li-ion) batteries, which are used on plug-in hybrids Both types of batteries share similar components: Battery Cells The battery’s power is stored in the battery cells. The cells contain electrolyte that can cause burns, but their multi-cell construction minimizes potential leakage if the battery is damaged. Battery cells are not serviceable and cannot be replaced individually.
Service Plug The service plug manually opens the HV battery circuit so no current can flow. The service plug should always be removed before servicing the hybrid system. System Main Relays System Main Relays (SMRs) connect and disconnect the high-voltage circuit between the battery and inverter. The SMRs are controlled by the HV ECU. Battery Smart Unit The Battery Smart Unit monitors battery operation and transmits information about battery voltage, current and temperature to the HV ECU. Cooling Fan The cooling fan circulates air to cool the HV battery. Collision Repair & Refinish Training 14