Battery Pack Voltage Follower Circuit for Accurate Cell Measurement
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Solution Overview
Problem
Existing voltage measurement systems in series-connected battery cells face challenges due to voltage drops caused by high impedance in connecting lines, which impair accuracy and require multiple supply lines, increasing costs and installation space.
Innovation Solution
A device using voltage followers and amplifier circuits to generate low-impedance supply voltages for voltage measuring devices, with a bypass circuit to conserve energy when not in use, allowing precise voltage measurement across series-connected battery cells with minimal supply lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional voltage measurement systems are used with high impedance connecting lines, then the system structure is simple, but voltage drops occur that impair measurement accuracy
Solution Approach 1:
A voltage follower circuit is introduced as an intermediary component between the battery cells and the voltage measuring device. The voltage follower has high input impedance that does not load the battery cells, and low output impedance that provides stable voltage to the measuring device, thereby eliminating voltage drops and improving measurement accuracy without requiring complex wiring changes
Solution Approach 2:
The patent changes the impedance parameters of the connection system by using a voltage follower with high input impedance and low output impedance. This parameter transformation allows the system to maintain simple wiring while achieving accurate voltage measurements by matching impedance characteristics between different system components
2Measurement precision
If multiple supply lines are used to compensate for voltage drops, then measurement accuracy is maintained, but installation space and costs increase
Solution Approach 1:
The voltage follower acts as an intermediary that eliminates the need for multiple supply lines by providing a low-impedance voltage source directly at the measurement location, thereby maintaining measurement accuracy while reducing installation space and simplifying the overall system architecture
3Measurement precision
If voltage followers are used to provide low impedance supply voltage, then measurement accuracy is improved, but energy consumption increases when not measuring
Solution Approach 1:
The system dynamically switches the voltage follower between active and inactive states based on measurement requirements. During normal operation, the voltage follower remains inactive to conserve energy. When voltage measurement is required, the control unit activates the voltage follower, ensuring low impedance supply and accurate measurement only when needed, thereby optimizing energy consumption while maintaining measurement precision
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
Enables precise voltage measurement with reduced impedance and minimal supply lines, saving costs and installation space while maintaining high accuracy, even when the system is not actively measuring.
Implementation Method 1
a voltage follower for at least two adjacent packs, which is connected to the current path between the two adjacent packs and receives a potential of the one pack as input signal, and also a reference voltage, and provides a supply voltage for the voltage measuring device of the other pack at low impedance as output signal
Data Source
AI summary
A device for determining cell voltages across series-connected battery cells of a cell stack is provided. The battery cells are combined to form packs having a plurality of series-connected battery cells. Each pack has an associated voltage measuring device for determining the cell voltages of the individual battery cells of the respective corresponding pack. The device has a voltage follower for at least two adjacent packs, which is connected to the current path between the two adjacent packs and receives a potential of the one pack as input signal, and also a reference voltage, and provides a supply voltage for the voltage measuring device of the other pack at low impedance as output signal.