Dual-Battery EV Power Architecture for Range and Fast Swapping
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Solution Overview
Problem
Electric vehicles face challenges in increasing energy density and reducing charging time of batteries, requiring high-power output and fast charging capabilities to enhance driving range and convenience.
Innovation Solution
The electric vehicle power system incorporates a high-energy-density main battery pack and a high-power fixed battery, with a dual DC-DC converter system allowing the fixed battery to assist during high-load conditions and be charged by the main battery pack, enabling quick battery replacement at swap stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the battery energy density is increased to extend driving range, then the driving range is extended, but the charging time increases and fast charging capability deteriorates
Solution Approach 1:
The power system is segmented into two independent battery packs: a main battery pack for energy storage and a fixed battery for power delivery. This segmentation allows each battery to be optimized for its specific function, resolving the contradiction between driving range and charging time.
Solution Approach 2:
The fixed battery acts as an intermediary between the main battery pack and the motor. It receives power from the main battery pack and delivers high-power output during acceleration, enabling fast charging capability without compromising driving range.
2Power
If the battery power output is increased to improve acceleration performance, then the acceleration performance is improved, but the energy density decreases and driving range is reduced
Solution Approach 1:
The battery system is divided into two functional segments: the main battery pack dedicated to energy storage for driving range, and the fixed battery dedicated to power delivery for acceleration performance. This segmentation resolves the contradiction between power and driving range.
Solution Approach 2:
Each battery pack is optimized with different local qualities: the main battery pack is designed for high energy density to maximize driving range, while the fixed battery is designed for high power density to maximize acceleration performance.
3Device complexity
If a single battery pack is used to simplify the system, then the device complexity is reduced, but the ability to provide both high energy density and fast charging capability deteriorates
Solution Approach 1:
The system is segmented into two battery packs with distinct functions, which initially increases structural complexity but enables the system to achieve both high energy density and fast charging capability simultaneously, resolving the contradiction between simplicity and versatility.
Solution Approach 2:
The dual battery pack system provides multi-functionality: the main battery pack handles energy storage for extended driving range, while the fixed battery handles power delivery for fast charging and high-performance acceleration, making the system adaptable to multiple operational requirements.
Data Source
AI summary
An electric vehicle power system, comprises: an electric motor, configured to provide power to an electric vehicle; a main converter coupled with the electric motor, and being a DC-to-AC converter or a DC-to-DC converter; a main battery pack electrically connected to the main converter through a first DC-DC converter; and a fixed battery electrically connected to the main converter through a second DC-DC converter.