Battery Pack Switching Circuit for Rapid Protection
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Solution Overview
Problem
Existing battery packs with protection circuits face challenges in rapidly switching off to protect against errors such as overcharge, overdischarge, or overcurrent due to longer switching times caused by external noise, which can lead to instability and potential damage.
Innovation Solution
A battery pack design incorporating a first switch with a capacitor for stabilization and a second switch in parallel, both controlled by distinct control signals, allowing for quicker turn-off of the first switch when the second switch is activated, utilizing a battery protection unit with current and voltage sensors to manage the switching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stability of the switches is improved to strongly protect against external noise, then the switching time of the switches increases
Solution Approach 1:
The protection circuit is segmented into two switches: a first switch for normal stable operation and a second switch for rapid emergency response. This segmentation allows each switch to be optimized for its specific function, resolving the contradiction between stability and speed.
Solution Approach 2:
The capacitor is pre-charged during normal operation, so when an emergency occurs, the second switch can immediately discharge it to rapidly turn off the first switch. This preliminary preparation enables fast response without compromising normal stability.
2Loss of time
If the switching time is reduced to protect against sudden errors, then the stability against external noise decreases
Solution Approach 1:
By dividing the protection function into two separate switches with different characteristics, the system can achieve both fast switching (second switch) and noise immunity (first switch with capacitor stabilization) simultaneously.
Solution Approach 2:
The capacitor acts as an intermediary energy storage element that enables the second switch to provide rapid response. The capacitor's pre-stored energy allows immediate action without directly compromising the stability of the first switch against external noise.
3Device complexity
If a single switch is used for protection, then the device complexity is low, but the switching speed is insufficient for sudden errors
Solution Approach 1:
The protection function is divided between two switches with specialized roles: the first switch handles normal operation with stability, while the second switch provides rapid emergency response. This functional segmentation achieves high speed without excessive complexity.
Solution Approach 2:
The system dynamically switches between two protection modes: normal mode using the first switch for stable operation, and emergency mode using the second switch for rapid response. This dynamic approach optimizes performance for different operating conditions.
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
This design achieves high stability and rapid switching times, effectively protecting the battery from errors by quickly turning off the first switch when abnormal conditions are detected, thereby preventing damage and ensuring stable operation.
Implementation Method 1
a capacitor electrically connected between the first electrode and the control electrode of the first transistor, and configured to stabilize a switching state of the first switch
Implementation Method 2
a second switch electrically connected in parallel to the capacitor, and configured to be switched in response to a second control signal
Data Source
AI summary
A battery pack includes a battery comprising at least one battery cell, a first switch electrically connected between the battery and an external terminal of the battery pack, and configured to be switched in response to a first control signal, a capacitor configured to stabilize a switching state of the first switch, a second switch electrically connected in parallel to the capacitor, and configured to be switched in response to a second control signal, and a battery protection unit configured to output the first and second signals.