Hybrid Electric Vehicle Battery Self-Heating via Internal Discharge
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Solution Overview
Problem
Current hybrid electric vehicles face challenges in low temperatures, where battery performance is reduced, leading to shortened battery life, safety concerns, and limited discharge capability, as lithium ions deposit at the negative electrode during charging, causing capacity loss and potential internal short circuits.
Innovation Solution
A power system for hybrid electric vehicles that includes a battery heater connected to the battery group, managed by a battery management device, which controls heating using internal battery discharge to maintain optimal temperature without external power, ensuring efficient heating and extended vehicle usage in cold conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If external power sources or thermal insulation materials are used to heat the battery, then the battery can be warmed in low temperature conditions, but the device complexity increases and the methods are not suitable for vehicles that are not fixed in position
Solution Approach 1:
The battery heating system uses the battery's own discharge capability to generate heat through internal resistance, eliminating the need for external power sources or complex thermal insulation structures. The battery group serves itself by converting electrical energy to thermal energy during controlled discharge cycles, thereby warming itself without requiring additional heating devices or insulation materials.
Solution Approach 2:
The patent extracts the heating function from external systems and integrates it into the battery's inherent electrical characteristics. By utilizing the battery's own discharge current and internal resistance, the system eliminates external heating devices, thermal insulation sleeves, and associated control mechanisms, achieving a simplified self-heating solution.
2Quantity of substance
If the battery is charged at low temperature, then the battery capacity can be restored, but lithium ions deposit at the negative electrode causing capacity loss and safety problems
Solution Approach 1:
Before charging the battery at low temperatures, the system performs preliminary heating by controlling the battery to discharge at a first power level, warming the battery to an appropriate temperature range. This preliminary thermal preparation prevents lithium ion deposition during subsequent charging operations, ensuring both capacity restoration and safety.
Solution Approach 2:
The battery management device continuously monitors battery temperature and adjusts discharge power accordingly. When temperature reaches the target range, the system automatically transitions from heating mode to charging mode, preventing overheating and ensuring optimal charging conditions are met before charge current is applied.
3Temperature
If the battery heater uses high power heating, then the battery can be heated quickly, but the battery's discharge capability is consumed reducing available power for vehicle operation
Solution Approach 1:
The battery heating process uses periodic discharge cycles rather than continuous high-power operation. The battery management device controls the battery to discharge at a first power level for heating, then pauses to allow temperature stabilization, creating a rhythmic heating pattern that minimizes energy consumption while achieving effective warming.
Solution Approach 2:
The system applies partial heating power rather than maximum power, using just enough discharge current to raise battery temperature to the acceptable range for charging. The heating power is carefully controlled to avoid excessive energy consumption, balancing thermal requirements with available power reserves for vehicle operation.
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
This solution allows for safe and efficient battery heating, maintaining performance and extending battery life by using the battery's internal discharge to generate heat, thus overcoming the limitations of existing technologies in low-temperature environments.
Implementation Method 1
a battery heater, connected with the battery group and 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 a hybrid electric vehicle, a hybrid vehicle comprising the same and a method for heating a battery group (101) of the hybrid electric vehicle are provided. The power system comprises a battery group (101), a battery heater (102) connected with the battery group (101), and a battery management device (103) configured to control the battery heater (102) to heat the battery group (101) with a first power or a second power when the hybrid electric vehicle is in an electric vehicle mode or a hybrid electric vehicle mode if the temperature of the battery group (101) is lower than a first heating threshold and a residual electric quantity of the battery group (101) is larger than a parking electric quantity threshold. The power system further comprises an electric distribution box (104), an engine (702), a motor (105), a motor controller (106) connected with the motor (105) and the electric distribution box (104) respectively, and an isolation inductor (L2).