Battery Pack Switch Control for Recoverable Overcurrent Shutdown
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Solution Overview
Problem
Existing high-voltage battery packs for environmentally-friendly vehicles face issues with system operation due to temporary overcurrent or short-circuit situations, where hardware protection circuits fail to properly manage switch states, leading to potential damage and operational disruptions.
Innovation Solution
A switch control device comprising an overcurrent detection circuit, counter circuit, latch circuit, and off circuit that outputs signals to control the switch, allowing for temporary overload or short-circuit recovery and permanent shutdown in continuous overload or short-circuit situations, using comparators, voltage dividers, capacitors, and transistors to manage switch states effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hardware protection circuit is used to monitor current and turn off the switch during overcurrent or short-circuit, then the switch can be protected from damage, but the switch cannot return to normal operation after temporary overload or short circuit is resolved
Solution Approach 1:
The protection system transitions from a static hardware circuit to a dynamic controller-based system that can adapt its response based on the nature and duration of the overcurrent condition. The controller monitors overcurrent detection signals over time and dynamically decides whether to temporarily or permanently latch the switch off state, enabling the system to recover from temporary faults while maintaining protection.
Solution Approach 2:
The system implements feedback by continuously monitoring the overcurrent detection signal and using this information to control the switch state. The controller receives feedback about the current condition and adjusts the switch control accordingly, allowing the system to return to normal operation when the overcurrent condition is resolved rather than maintaining a permanent off state.
2Reliability
If the switch is turned off during overcurrent or short-circuit to protect the battery pack, then damage is prevented, but the battery pack cannot return to normal operation even after the fault is resolved
Solution Approach 1:
The system dynamically adjusts the switch control based on the duration and persistence of the overcurrent condition. For temporary faults, the system allows recovery and returns to normal operation. For persistent faults, the system maintains the protective off state. This dynamic response optimizes both protection and operational availability.
Solution Approach 2:
The controller continuously monitors the overcurrent detection signal and uses this feedback to determine whether to maintain or release the switch off state. When the overcurrent condition is resolved (no detection signal for a predetermined period), the controller feedbacks a command to restore normal operation, thereby maintaining productivity while ensuring protection.
3Adaptability or versatility
If a controller-based protection system is implemented to monitor and control the switch, then the system can distinguish between temporary and continuous overcurrent conditions, but the device complexity increases compared to hardware-only protection circuits
Solution Approach 1:
The controller serves multiple functions: it monitors overcurrent conditions, determines the nature of the fault (temporary vs. continuous), controls the switch state, and manages the recovery process. By consolidating these functions into a single controller rather than requiring separate hardware circuits for each function, the system achieves high adaptability without proportionally increasing complexity.
Solution Approach 2:
The patent replaces complex hardware protection circuits with a controller-based electronic system. The controller uses software/logic to implement the protection methodology, substituting mechanical or hardwired protection logic with flexible electronic control. This substitution reduces physical complexity while maintaining or enhancing protection capabilities.
Data Source
AI summary
A switch control device including: an overcurrent detection circuit configured to output an overcurrent detection signal if an overcurrent is detected in a current path in which a switch is disposed; a counter circuit configured to output a latch control signal whose voltage is varied in response to a number of outputs of the overcurrent detection signal; a latch circuit configured to continuously output a latch signal if the voltage of the latch control signal is higher than a predetermined voltage; and an off circuit configured to output an off signal controlling the switch to be turned off if the overcurrent detection signal is outputted from the overcurrent detection circuit or the latch signal is outputted from the latch circuit.