Inverter AC Heating for EV Battery Packs
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Solution Overview
Problem
Batteries face significant discharge capacity degradation and inability to charge in low temperature environments, requiring inefficient and time-consuming heating methods.
Innovation Solution
A battery heating system comprising a main positive switch, main negative switch, inverter, motor, and battery management unit, where the inverter includes phase bridge arms with switch units and a motor controller to generate alternating current for internal resistance heating, ensuring uniform and high-efficiency heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If indirect heating through thermal cycle container is used, then battery heating is achieved, but heating time is long and heating efficiency is low
Solution Approach 1:
The patent replaces the mechanical thermal cycle container heating system with an electrical heating system. The inverter generates alternating current that passes through the battery pack, utilizing Joule heating to directly heat the battery. This substitution of mechanical/thermal system with electrical system achieves rapid and efficient heating, resolving the contradiction between heating efficiency and heating time.
Solution Approach 2:
The battery pack itself serves as the heating element by utilizing its internal resistance. The alternating current generated by the inverter passes through the battery pack, and the battery's internal resistance converts electrical energy into thermal energy directly within the battery. This self-service approach eliminates the need for external heating devices and achieves rapid heating.
2Adaptability or versatility
If special thermal cycle container and heat-conducting material are added, then battery heating function is achieved, but device complexity increases
Solution Approach 1:
The inverter, which is already a necessary component for motor control in electric vehicles, is made to serve dual functions: motor control and battery heating. By controlling the switch units in the inverter's bridge arms, the system can generate alternating current for both motor operation and battery heating. This multi-functionality approach adds heating capability without increasing device complexity.
Solution Approach 2:
The battery pack uses its own internal resistance as the heating element, eliminating the need for external heating devices, thermal cycle containers, or heat-conducting materials. The existing battery structure serves the dual purpose of energy storage and heat generation, achieving heating function without additional structural modifications.
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 efficiently heats the battery pack by alternating current passing through its internal resistance, improving heating speed and uniformity without structural modifications, enabling normal operation in low temperatures.
Implementation Method 1
The system efficiently heats the battery pack by alternating current passing through its internal resistance
Data Source
AI summary
The present disclosure provides a battery heating system and a control method thereof. The battery heating system includes a main positive switch, a main negative switch, an inverter, a motor, and a battery management unit. The inverter includes a first phase bridge arm, a second phase bridge arm and a third phase bridge arm connected in parallel. A motor controller in the inverter is configured to output a drive signal to a target upper-bridge-arm switch unit and a target lower-bridge-arm switch unit, so as to control the target upper-bridge-arm switch unit and the target lower-bridge-arm switch unit to be periodically turned on and off. The battery management unit is configured to collect state parameters of the battery pack. When the state parameters of the battery pack meet preset heating conditions, a control signal is sent to the motor controller to control the motor controller to output the drive signal.