EV Battery Preheating With Multi-Stage Cold Weather Charge Control
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Solution Overview
Problem
Electric vehicle batteries experience poor performance in cold weather due to inadequate preheating strategies, leading to inefficient energy use and low state of charge when the vehicle is started after charging, as battery heaters typically turn off post-charging and rely on the vehicle's own energy to maintain temperature.
Innovation Solution
A multi-level battery heating strategy that estimates the vehicle start time based on charging duration, parking time, and driving distance to optimize battery preheating, utilizing both AC/DC charge power and battery heater power to maintain target temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the battery heater is turned off after achieving target temperature or after charge session completion, then energy consumption is reduced, but the battery temperature drops before vehicle use
Solution Approach 1:
The system performs preliminary heating action by estimating the vehicle start time based on charging duration, parking time, and driving distance patterns. The battery heater is activated before the vehicle is actually needed, ensuring the battery reaches optimal temperature before use, thereby avoiding the need for continuous heating and reducing overall energy consumption.
2Use of energy by stationary object
If the battery heater utilizes charger energy during charge session, then heating efficiency is improved, but the charger high voltage system disconnects after charging completing
Solution Approach 1:
The system takes preliminary action by completing the battery heating process during the charge session while the charger is connected and high voltage system is active. By estimating the vehicle start time and calculating required heating duration, the system ensures heating is completed before the charger disconnects, maximizing utilization of external power source for heating.
Solution Approach 2:
The system uses the charger's high voltage power to serve the heating function during charging, making the charging process multi-functional. The battery heater draws power from the charging system to heat the battery, effectively using the stationary power source for both charging and heating purposes before disconnection occurs.
3Reliability
If the battery heater uses EV's own state of charge to heat battery, then heating capability is maintained, but state of charge becomes low when vehicle is driven
Solution Approach 1:
The system performs preliminary heating during the charge session before the vehicle is driven. By calculating the estimated vehicle start time and required heating duration, the system completes battery heating while external power is available, preventing the need to deplete state of charge for heating purposes and ensuring adequate SOC remains for driving.
4Productivity
If multi-level heating strategy is implemented with temperature thresholds, then heating optimization is improved, but control system complexity increases
Solution Approach 1:
The system implements multi-level heating control by changing the heating power parameter based on temperature thresholds. Three distinct heating levels are defined: Level 1 for temperatures below -5°C, Level 2 for temperatures between -5°C and 5°C, and Level 3 for temperatures between 5°C and 10°C. This parameter-based control approach optimizes heating efficiency while maintaining relatively simple control logic through predefined temperature breakpoints.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances battery performance in cold weather by maintaining optimal temperatures before use, optimizing energy usage, and preventing low state of charge upon vehicle start.
Implementation Method 1
battery heaters configured to heat up (raise the temperature of) the battery
Data Source
AI summary
Systems and methods for preheating a battery heater of an electric vehicle (EV) are provided. The method may comprise determining an estimated vehicle start time for the EV, determining whether an ambient temperature of a battery is less than −5° C., when the ambient temperature of the battery is less than −5° C., performing a level 1 heating function, when the ambient temperature of the battery is not less than −5° C., determining whether the ambient temperature of the battery is between −5° C. and 5° C., when the ambient temperature of the battery is between −5° C. and 5° C., performing a level 2 heating function, when the ambient temperature of the battery is above −5° C. and not between −5° C. and 5° C., then, determining whether the ambient temperature of the battery is between 5° C. and 10° C., and when the ambient temperature of the battery is between 5° C. and 10° C., performing a level 3 heating function.