Relay Operation State Maintaining Device for EV Battery Safety
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Solution Overview
Problem
In electric vehicle battery systems, abnormalities in the control device can lead to unintended relay openings, posing safety hazards due to the loss of electrical connection between the battery pack and the vehicle body, especially during high-speed travel.
Innovation Solution
A relay operation state maintaining device that includes a memory to store relay control signals, a first relay driving signal generator, and a second relay driving signal generator, operated by a separate power supply, which generates and outputs signals to maintain the relay state even during controller failures, using logic operations and a timer to ensure stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a controller is used to control relay operations in a battery pack system, then the relay operation can be automated and controlled, but the system becomes vulnerable to controller failures that can cause unintended relay openings and safety hazards
Solution Approach 1:
A dedicated relay operation state maintaining device is introduced as an intermediary component between the controller and the relay. This device includes a memory that stores the last known good relay control signal and circuitry that can output this stored signal when the controller fails, thereby maintaining relay operation state and preventing unintended relay openings during controller abnormalities
Solution Approach 2:
The memory component is pre-loaded with the relay control signal before any failure occurs. This beforehand preparation ensures that when a controller failure happens, the stored signal is immediately available to maintain relay operation without interruption, cushioning against the potential harm of controller failure
2Device complexity
If the relay control system relies solely on the controller, then the device complexity is reduced, but the system loses the ability to maintain relay operation state during controller failures
Solution Approach 1:
The control system is segmented into two independent functional parts: the primary controller that handles normal relay control operations, and a secondary maintaining device with memory that handles failure recovery. This segmentation allows the system to gain reliability through redundancy while keeping each component relatively simple in structure
3Reliability
If a separate power supply is used for the memory and signal generators, then the relay control system becomes independent of controller power failures, but the device complexity and power supply requirements increase
Solution Approach 1:
A separate power supply is introduced as a dedicated intermediary power source specifically for the memory and signal generating components. This independent power supply ensures that these critical components remain operational even when the main controller loses power, providing power supply independence and enhancing overall system reliability during power failure scenarios
Data Source
AI summary
In a relay operation state maintaining device configured to maintain an operation state of a relay when an abnormality occurs in a controller configured to control an operation of the relay, the relay operation state maintaining device includes: a memory configured to store a relay control signal output for an operation of the relay by the controller at a time the abnormality occurs and to generate and output a memory output signal based on a stored signal; a first relay driving signal generator configured to generate and output a first relay driving signal based on the relay control signal and a signal corresponding to the abnormality occurrence; and a second relay driving signal generator configured to generate and output a second relay driving signal based on the first relay driving signal and the memory output signal.