Lead-acid battery for hybrid cars

The lead-acid battery used in hybrid cars plays a different role compared to the traditional lead-acid batteries found in conventional gasoline-powered vehicles. Hybrid cars combine an internal combustion engine (ICE) with one or more electric motors, and they typically rely on two types of batteries:

High-voltage battery (typically Nickel-Metal Hydride (NiMH) or Lithium-ion (Li-ion)) for powering the electric motor and storing energy from regenerative braking.
12V lead-acid battery, similar to the one found in conventional cars, which powers the vehicle's standard electrical components, such as lights, infotainment systems, and other accessories.

Advantages of Lead-Acid Batteries in Hybrid Vehicles:

Cost-Effective: Lead-acid batteries are relatively inexpensive compared to more advanced lithium-ion batteries, which is why they are often used for the 12V auxiliary system in hybrid cars.

Proven Technology: Lead-acid batteries have been used in vehicles for over a century and are well understood. Their technology is mature and reliable, which is essential for non-traction applications in hybrid cars.

Widespread Availability: Lead-acid batteries are readily available and can be easily replaced, making them an attractive option for hybrid vehicles.

Maintenance-Free Options: Modern 12V lead-acid batteries, such as AGM (Absorbent Glass Mat) or VRLA (Valve-Regulated Lead-Acid) batteries, are maintenance-free and do not require regular electrolyte checks or top-ups, providing a hassle-free experience.

How Lead-Acid Batteries Are Integrated into Hybrid Systems？

Powering Traditional Vehicle Systems:

The 12V lead-acid battery is connected to a DC-DC converter that regulates voltage between the high-voltage battery (typically 100V-300V) and the 12V system. This ensures the 12V battery gets charged without compromising the performance of the high-voltage battery.

Regenerative Braking:

During braking, the vehicle’s electric motor functions as a generator, converting kinetic energy into electrical energy, which is then stored in the high-voltage battery. The 12V lead-acid battery is indirectly affected, as the DC-DC converter ensures that the car's electronics continue to function.

Engine Start-Stop Systems:

Some hybrid cars have start-stop systems, which automatically turn off the engine when the car is idling and restart it when the accelerator is pressed. The 12V battery is used to start the engine in such systems, and the lead-acid battery needs to be robust enough to handle frequent starts and stops.