Battery Voltage Balancing Circuit With Thermal Bleeder Control
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Solution Overview
Problem
Conventional battery packs lack effective voltage balancing during charging, leading to uneven cell charging and potential overheating of bleeder resistors, which can damage other components.
Innovation Solution
A voltage balance circuit comprising a battery module, a voltage dividing module with bleeder resistors, a detection module using thermistors and micro-controllers, and a control module with MOSFET switches, which dynamically adjusts the bleeder resistor's operation based on temperature readings to maintain optimal charging and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bleeder resistors are used to balance voltage in each battery cell, then voltage balancing is achieved, but the bleeder resistors generate heat that can damage other components
Solution Approach 1:
The patent applies dynamics by making the bleeder resistor circuit switchable rather than fixed. MOSFETs are used to dynamically connect or disconnect the bleeder resistors based on real-time temperature monitoring. When temperature exceeds a threshold, the MOSFET disconnects the bleeder resistor to prevent overheating; when temperature is within safe range, the bleeder resistor is reconnected to perform voltage balancing. This dynamic adjustment resolves the contradiction between maintaining voltage balancing functionality and preventing heat-induced damage.
2Productivity
If continuous voltage balancing is performed using bleeder resistors, then all batteries can be fully charged, but the bleeder resistors continuously generate heat
Solution Approach 1:
The patent implements periodic action by interrupting the continuous operation of bleeder resistors. Instead of continuous discharge, the system periodically connects and disconnects the bleeder resistors based on temperature conditions. The MOSFET-controlled switching creates periodic on/off cycles: when temperature is safe, the bleeder resistor operates to balance voltage; when temperature rises, it is disconnected to allow cooling. This periodic operation maintains charging productivity while reducing continuous energy loss to heat.
3Object-affected harmful factors
If temperature monitoring and control systems are added to manage bleeder resistor operation, then heat damage is prevented, but device complexity increases
Solution Approach 1:
The patent applies feedback by implementing a temperature monitoring system that continuously measures the temperature of bleeder resistors and uses this information to control the MOSFET switching. The microcontroller reads temperature data from sensors (such as thermistors or RTDs) connected to the bleeder resistor housing, compares it against predefined thresholds, and automatically adjusts the MOSFET gate voltage to connect or disconnect the bleeder resistor accordingly. This closed-loop feedback mechanism prevents heat damage while maintaining relatively simple circuit architecture through automated control.
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 circuit ensures continuous voltage balancing of batteries and controls bleeder resistor temperature, preventing damage and ensuring all batteries are fully charged while maintaining efficient energy use.
Implementation Method 1
The detection module includes a plurality of thermistors, a plurality of fixation resistances and a plurality of micro-controllers. Each thermistor is arranged beside one bleeder resistor. Each thermistor is connected with one fixation resistance in series
Implementation Method 2
When an electric current flows into the bleeder resistor, an electric energy is converted into a heat energy to be consumed, so a temperature of the bleeder resistor will continue rising
Data Source
AI summary
A voltage balance circuit includes a battery module connected to an external power source, a voltage dividing module, a detection module and a control module. The battery module includes a plurality of batteries connected in series. The voltage dividing module includes a plurality of bleeder resistors. Each bleeder resistor is connected with one battery in parallel. The detection module includes a plurality of thermistors, fixation resistances and micro-controllers. Each thermistor is arranged beside one bleeder resistor. Each thermistor is connected with one fixation resistance in series. Each micro-controller is connected with one thermistor and the one fixation resistance. The control module includes a plurality of switches and an analog front end component. Each switch is connected with the one bleeder resistor in series. Each switch is connected to the analog front end component, and the analog front end component is connected to the one micro-controller.