In EVs, which device is commonly used to deliver rapid bursts of power for acceleration as a secondary energy storage?

In EVs, which device is commonly used to deliver rapid bursts of power for acceleration as a secondary energy storage?

• A. Ultracapacitors
• B. Lithium-ion batteries
• C. Lead-acid batteries
• D. Nickel-metal hydride batteries

Answer: (A)

Delivering a quick, high-power burst for acceleration requires a device with very high power density and ultra-fast response, plus the ability to endure many rapid charge–discharge cycles. Ultracapacitors fit that role perfectly, acting as a secondary energy storage to provide that bursts of energy during acceleration and to absorb energy quickly during regenerative braking. They can deliver large amounts of current in a short time without stressing the main battery, which helps keep the primary pack from degrading under peak power demands. In contrast, lithium-ion batteries store most of the energy for range but have lower instantaneous power capability and slower response, so they aren’t as effective for peak power needs. Lead-acid and nickel-metal hydride batteries offer far lower power density and heavier weight, making them impractical for rapid acceleration bursts.

Delivering a quick, high-power burst for acceleration requires a device with very high power density and ultra-fast response, plus the ability to endure many rapid charge–discharge cycles. Ultracapacitors fit that role perfectly, acting as a secondary energy storage to provide that bursts of energy during acceleration and to absorb energy quickly during regenerative braking. They can deliver large amounts of current in a short time without stressing the main battery, which helps keep the primary pack from degrading under peak power demands. In contrast, lithium-ion batteries store most of the energy for range but have lower instantaneous power capability and slower response, so they aren’t as effective for peak power needs. Lead-acid and nickel-metal hydride batteries offer far lower power density and heavier weight, making them impractical for rapid acceleration bursts.