EV Battery Self-Heating via Intermittent Discharge
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Solution Overview
Problem
Electric vehicles face challenges in low temperatures due to reduced battery performance, safety risks, and limited discharge capability, as lithium-ion batteries deposit ions at low temperatures, leading to shortened lifespan and potential safety hazards.
Innovation Solution
A power system for electric vehicles that includes a battery heater connected to the battery group, a battery management device to control intermittent heating based on temperature and residual charge, and an isolation inductor to match capacitance, allowing the battery to heat itself through large current discharge without external power, optimizing heating efficiency and extending battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external power is used to heat the battery, then heating effectiveness is improved, but device complexity and cost increase
Solution Approach 1:
The battery heater utilizes the battery group's own residual electric quantity to generate heating current, enabling the system to heat itself without requiring external power sources. The battery management device controls the heater to discharge the battery group, and the internal resistance of the battery converts electrical energy into thermal energy for self-heating.
Solution Approach 2:
The patent extracts and utilizes the residual electric quantity already present in the battery group for heating purposes, rather than adding external heating systems. The battery management device directs the battery group's own energy to the heater, which then converts this electrical energy into heat through the battery's internal resistance.
2Productivity
If large current is used to heat the battery, then heating efficiency is improved, but battery damage and safety risks increase
Solution Approach 1:
The battery management device controls the battery heater to operate intermittently rather than continuously. The system activates the heater when the battery temperature is below the first threshold and residual electric quantity is above the electric quantity threshold, then pauses when thresholds are met, creating a periodic heating pattern that prevents overheating and excessive current damage.
Solution Approach 2:
The battery management device continuously monitors the battery group's temperature and residual electric quantity, using this feedback to control the battery heater's operation. When temperature reaches the first threshold or electric quantity drops to the threshold, the device automatically adjusts or stops heating, ensuring safe operation.
3Quantity of substance
If the battery is charged at low temperature, then battery capacity is improved, but ion deposition and safety hazards occur
Solution Approach 1:
The system performs preliminary heating of the battery group before charging operations when the temperature is below the first threshold. By activating the battery heater using the battery's own residual energy, the system raises the battery temperature to an acceptable range prior to charging, preventing ion deposition and safety hazards that would occur with cold-temperature charging.
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
The system effectively heats the battery group at low temperatures, ensuring safe and smooth operation, reducing the negative impacts of large current on the battery and prolonging its lifespan while maintaining performance and safety.
Implementation Method 1
configured to charge and discharge the battery group to heat the battery group
Implementation Method 2
an isolation inductor, connected between the battery group and the electric distribution box, in which an inductance of the isolation inductor matches with a capacitance of the pre-charging capacitor
Data Source
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AI summary
A power system of an electric vehicle, an electric vehicle comprising the same and a method for heating a battery group (101) of the electric vehicle are provided. The power system of the electric vehicle comprises a battery group (101), a battery heater (102) connected with the battery group (101), and a battery management device (103) connected with the battery group (101) and the battery heater (102) respectively. The battery management device (103) is configured to control the battery heater (102) to heat the battery group (101 ) intermittently when the temperature of the battery group (101) is lower than a first temperature threshold and a residual electric quantity of the battery group (101) is larger than an electric quantity threshold. The power system further comprises an electric distribution box (104), a motor (105), a motor controller (106) connected with the motor (105) and the electric distribution box (104) respectively, and an isolation inductor (L2).