Battery Explosion-Proof Circuit with Current Limiting Resistor
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Solution Overview
Problem
Current battery protection circuits may fail to accurately limit load current, leading to overheating and damage of electronic switches, and can cause secondary hazards by storing electric charge without release, while also being unsafe during charging due to simple design and potential back discharge issues.
Innovation Solution
A discharging protection circuit with a current limiting module that includes a comparing unit and a controlled switch with MOS transistors and resistors, which disconnects the switch when excessive current is detected, directing it through a current limiting resistor to safely release battery charge, and additional modules for overcurrent and temperature protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current limiting circuit with electronic switch is used to prevent battery explosion, then battery safety is improved, but the circuit may fail to accurately limit current causing overheating and damage of the electronic switch
Solution Approach 1:
The patent introduces a current limiting resistor as an intermediary component between the battery and the electronic switch. This resistor limits the maximum current that can flow through the circuit, preventing the electronic switch from being exposed to excessive current that would cause overheating and damage. The intermediary component thus protects the main protective device while maintaining the safety function.
Solution Approach 2:
The current limiting resistor is pre-installed in the circuit to provide beforehand cushioning against excessive current. By having this protective component in place before any failure occurs, the circuit is pre-prepared to handle abnormal current conditions, preventing the electronic switch from being damaged by sudden current surges during battery failures or before troubleshooting.
2Reliability
If the current limiting circuit cuts off the battery in failure state to prevent explosion, then battery explosion risk is reduced, but the stored electric quantity cannot be released causing secondary hazards
Solution Approach 1:
The patent applies different protective strategies to different parts of the circuit based on local conditions. The current limiting resistor provides continuous current limitation for safe charge release, while the electronic switch provides selective cutoff for explosion prevention. This localized quality approach allows the circuit to simultaneously achieve both explosion prevention and safe energy dissipation by having different components perform different functions in different operational states.
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 solution effectively limits load current, prevents overheating, and ensures safe battery discharge, while avoiding secondary hazards by releasing battery charge through a current limiting resistor and providing additional protection against overcurrent and temperature.
Implementation Method 1
a first comparing unit for detecting whether the current flowing through the load exceeds a first discharging threshold value of the battery
Implementation Method 2
a current limiting unit including a controlled switch and a current limiting power resistor connected in parallel to both ends of the controlled switch
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An explosion-proof circuit, a charging circuit and a charging/discharging protection circuit of a battery are disclosed. In the explosion-proof circuit and charging circuit of the battery, when a load is short-circuited, the voltage at the output end of a power electronic switch (QI) is close to the voltage of the negative electrode of the battery, and the voltage of the battery is divided by a control resistor (R9) and a feedback resistor (R15), so that a feedback control switch (Q3) is switched on, thus enabling the power electronic switch (QI) to be in a cut-off state; the load current is cut off to protect the power electronic switch (QI) from damage; and meanwhile, the electric quantity of the battery is released in a relatively small safe current by a current limiting resistor (R7), the control resistor (R9) and the feedback resistor (R15), thereby avoiding the problem that the battery generates secondary hazards due to the fact that the electric quantity of the battery is stored in the battery and cannot be released. Since it is not necessary to give an accurate reference voltage, it is guaranteed that the circuit can reliably limit the load current, and it will not cause all the power consumption to be loaded on the electronic switch, which would result in overheating and damaging of the electronic switch.