Why Do Hybrid and Electric Vehicles Use Multiple Battery Packs?

Hybrid and electric vehicles (EVs) utilize multiple battery packs for a variety of reasons, primarily to maximize safety, convenience, and system reliability. Understanding the importance of these setups helps to explain why modern vehicles incorporate both a 12-Volt (12V) and a high-voltage battery for essential operations.

The Importance of 12V Batteries

Most vehicles, whether they are hybrids, electric cars, or even traditional internal combustion engine (ICE) vehicles, rely on 12V batteries for powering various standard components. These components include:

Headlights Entertainment systems Windshield wipers Door locks Seating and seat adjustment mechanisms Heating and cooling systems

These devices and systems are optimized for 12V power, and changing to a higher voltage (like 200V) would be extraordinarily inconvenient and costly. It would require significant rework of existing automotive electrical systems and components. Moreover, not all models of a vehicle might ever be equipped with a high-voltage system, making it impractical to switch to a higher voltage solution by default.

High-Voltage Batteries: Safety and Efficiency

The high-voltage battery, typically found in EVs and hybrids, powers the electric motors and other high-power systems within the vehicle. These batteries are built from multiple cells connected in parallel and series to achieve the necessary voltage and power output. For instance, the high-voltage battery in a Tesla Model S/X is composed of several battery packs to provide the required power for the vehicle's electric drive system and other high-power components.

A high-voltage battery, often ranging between 200V and 800V (as in the case of Tesla), is inherently more dangerous due to its higher voltage and larger capacity. This necessitates a robust safety system to ensure that only when all checks are in order, the high power source is enabled. The 12V battery serves as an auxiliary power source for system checks, ensuring safety and reliability.

Redundancy and Safety: The Split Battery System

A key feature in modern electric vehicles, particularly those with advanced features like self-driving capabilities, is the use of multiple battery packs for redundancy. For instance, Tesla uses a dual-battery pack setup to ensure that the vehicle can continue moving even if one battery pack fails. This is critical for safety considerations, especially in scenarios where the vehicle needs to be driven to a safe location in the event of a significant malfunction.

This split battery system allows the vehicle to maintain full functionality until it can be charged or stopped safely. Such an approach not only enhances safety but also ensures that the vehicle can operate even in the event of a critical system failure. This is a significant advantage in today's era of autonomous vehicles, where reliability and safety are paramount.

Conclusion

In summary, the use of multiple battery packs in hybrid and electric vehicles is a strategic decision that balances safety, convenience, and efficiency. The 12V battery safely manages essential vehicle operations, while the high-voltage battery powers the electric drive system and other high-power components. The dual-battery pack system ensures redundancy and enhances safety, making modern EVs and hybrids not only efficient but also robust and reliable.

By understanding these systems, manufacturers and consumers can better appreciate the complexity and importance of these technologies in the evolving automotive landscape.