Electric Traction Drive Battery Module Bypass Control
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Solution Overview
Problem
In electric traction drive systems, especially in hybrid and electric vehicles, the failure of a battery cell can lead to an unsafe state, causing unintended torque outputs and potential damage to the inverter, necessitating costly additional measures like mechanical freewheels to maintain vehicle dynamics, which are only required during faults and thus unnecessary.
Innovation Solution
A method and device that monitor battery modules in an electric traction drive system, allowing immediate bypassing of faulty modules within a battery module line, ensuring continuous operation with connected modules, maintaining torque stability until a fault diagnosis can be performed, and enabling operation with reduced performance if necessary, without additional hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical freewheels are added to maintain vehicle dynamics during battery faults, then vehicle safety and dynamics are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical freewheels with an electrical control solution. The bypass contactor electrically isolates faulty battery modules, allowing the remaining healthy modules to continue supplying power to the inverter and motor, thereby maintaining vehicle dynamics without mechanical components.
Solution Approach 2:
The patent extracts or removes faulty battery modules from the circuit using bypass contactors when failures are detected. This isolation technique allows the healthy modules to continue operating independently, maintaining system functionality without requiring additional mechanical protection devices.
2Reliability
If battery modules are monitored and bypassed upon failure detection, then reliability and continuous operation are improved, but device complexity increases due to monitoring and switching components
Solution Approach 1:
The patent implements preliminary monitoring of battery module parameters (voltage, temperature, current) to detect potential failures before they cause system-wide issues. The control unit continuously evaluates these parameters and prepares bypass contactors for immediate activation, enabling preventive maintenance and continuous operation.
Solution Approach 2:
The patent introduces bypass contactors as intermediary components between the battery modules and the inverter. These contactors act as electrical switches that can isolate faulty modules while allowing healthy modules to continue supplying power, serving as a mediator that maintains system operation during partial failures.
3Power
If all battery modules are connected in series to maximize output voltage, then power output is improved, but reliability decreases when a single module fails
Solution Approach 1:
The patent segments the battery system into multiple independent modules, each with its own bypass contactor. This segmentation allows individual modules to be isolated without affecting the operation of other modules, transforming a single-point-failure system into a modular redundant system that maintains power output even when some modules fail.
Data Source
AI summary
A method for operating an electric traction drive system includes monitoring each of battery modules during operation for satisfactory functioning to detect a technical fault. The method further includes bypassing at least one battery module if a technical fault of the at least one battery module is detected. The method further includes operating the traction drive system in a traction state where an electric motor is supplied and actuated by connected battery modules to the battery module line to enable a currently generated torque to remain unchanged. The electric motor and the battery are positioned to generate an adjustable output voltage of the battery. The battery is configured to supply the electric motor. The battery includes a battery module line and the battery modules. The battery modules are configured to be connected in series with the battery module line or bypassed in the battery module line.