Battery Charge Power Derating for Regenerative Descent Control
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Solution Overview
Problem
Regenerative braking in electric vehicles can lead to battery overcharging during prolonged driving from high altitude to low altitude, necessitating a disconnect between the battery and vehicle system, which results in loss of power.
Innovation Solution
A method for derating battery charging power by calculating a prediction value of charging current increase based on altitude and descent speed data, and adjusting the charging power accordingly using a battery management system and protection devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is used during prolonged driving from high altitude to low altitude, then battery charging efficiency is improved, but battery overcharging occurs
Solution Approach 1:
The battery management system performs preliminary assessment of altitude change and descent speed before regenerative braking occurs. By calculating the prediction value of charging current increase based on altitude data and descent speed data in advance, the system proactively determines whether to derate charging power, preventing overcharging before it occurs.
Solution Approach 2:
The system continuously monitors altitude data from positioning systems or altitude sensors and descent speed data, calculates the prediction value of charging current increase, and adjusts charging power accordingly. This closed-loop feedback mechanism ensures charging efficiency is maximized while preventing battery overcharging during altitude descent.
2Reliability
If connection between battery and vehicle system is severed to prevent overcharging, then battery overcharging is prevented, but power supply to vehicle is lost
Solution Approach 1:
Instead of severing the connection between battery and vehicle system, the invention changes the charging power parameter by derating it according to the prediction value of charging current increase. This allows the battery to remain connected and continue supplying power to the vehicle while adjusting charging power to safe levels, avoiding both overcharging and power loss.
3Reliability
If charging power is derated based on altitude and descent speed data, then battery overcharging is prevented, but system complexity increases
Solution Approach 1:
The battery management system performs multiple functions using the same data acquisition and calculation infrastructure. The system obtains altitude data and descent speed data for both vehicle control and battery charging management, calculating prediction values that serve both safety and charging optimization purposes, thereby reducing overall system complexity.
Data Source
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AI summary
A method for derating a charge power of a battery (212), includes: obtaining altitude data (232) of a vehicle; obtaining descent speed data (234) of the vehicle; calculating, based on the altitude data (232) and the descent speed data (234), a prediction value of an increase in a charging current of the battery (212) equipped in the vehicle due to regenerative braking; and derating the charging power of the battery (212) based on the calculated prediction value.