Battery Pack Overcharge Protection via Fuse Short Circuit
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Solution Overview
Problem
Conventional battery pack overcharge protection systems are not always effective, particularly in large battery packs, as they can fail due to high voltage issues, leading to simultaneous thermal runaway of all cells, which is catastrophic in safety-sensitive applications like electric vehicles.
Innovation Solution
An overcharge protection device (OPD) is introduced, which creates a short across the battery pack terminals when an overcharging event is detected, triggering a fuse to interrupt the charging current, providing an additional layer of protection independent of contactors and charging circuits. The OPD can be implemented using solid-state devices, crowbar circuits, or solenoid relay switches, without a microprocessor or secondary power source, and is designed to operate between the battery pack terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional overcharge protection systems (voltage sensing circuits, contactors, charging circuit monitoring) are used, then overcharge protection is provided, but system complexity increases and reliability decreases due to multiple potential failure points
Solution Approach 1:
The invention extracts the overcharge protection function from the complex system of voltage sensing circuits, contactors, and charging circuit monitoring, and implements it through a simple fuse-based mechanism. The fuse element directly responds to overcharge conditions through voltage breakdown, eliminating the need for complex electronic protection systems while improving reliability.
Solution Approach 2:
The invention uses a disposable fuse element that breaks under overcharge conditions to provide protection. This simple, low-cost component replaces complex, expensive electronic protection systems. The fuse is designed to fail safely by breaking the circuit when overcharge occurs, providing reliable protection without the complexity of reusable electronic systems.
2Reliability
If voltage sensing circuits and contactors are used for overcharge protection, then charging interruption is achieved, but the system remains vulnerable to simultaneous failure of multiple components
Solution Approach 1:
The invention implements beforehand cushioning by designing a fuse element with specific breakdown characteristics that activate before dangerous overcharge conditions can cause thermal runaway. The fuse provides a safety margin by breaking at a predetermined voltage threshold, cushioning against the harmful effects of overcharge before they can manifest as catastrophic failure.
Solution Approach 2:
The fuse element acts as an intermediary between the battery pack and the charging system. It provides a simple, reliable interface that automatically interrupts charging when overcharge conditions are detected, without requiring complex control systems or multiple moving parts that could fail simultaneously.
3Reliability
If multiple protection layers (charging circuit monitoring, contactor interruption) are implemented, then overcharge protection is enhanced, but the system becomes more complex and prone to coordinated failures
Solution Approach 1:
The invention extracts the essential protection function from the complex multi-layer system and implements it through a single fuse element. By taking out only the critical voltage interruption function and implementing it through a simple fuse, the system achieves reliable protection without the architectural complexity of multiple coordinated protection layers.
Solution Approach 2:
The fuse element provides self-service protection by automatically breaking the circuit when overcharge conditions occur. It requires no external control, monitoring, or coordination with other system components. The fuse simply responds to the voltage condition and interrupts charging when needed, providing autonomous, fail-safe protection.
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 OPD effectively prevents overcharging by ensuring the battery pack fuse blows, preventing thermal runaway and providing an additional layer of protection that is less susceptible to system failures, thereby enhancing safety in battery packs, especially in critical applications like electric vehicles.
Implementation Method 1
the OPD creates a short across the terminals of the battery pack causing a battery pack fuse designed to provide battery pack short circuit protection to blow
Data Source
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AI summary
An overcharge protection device (OPD) is provided that may be used alone, or in combination with conventional charging protection systems, to protect a battery pack from the occurrence of a potentially damaging overcharging event.The OPD is designed to be coupled to, and interposed between, the terminals of the battery pack. During normal system operation, the OPD has no effect on the operation of the charging system or the battery pack. During an overcharging event, if overcharging is not prevented by another conventional system, the OPD of the invention creates a short across the terminals of the battery pack causing a battery pack fuse designed to provide battery pack short circuit protection to blow, thereby interrupting the current path from the charger to the battery pack and preventing the battery pack from being overcharged.