Zener Diode Constant Voltage Circuit for Battery Module Charge Control
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Solution Overview
Problem
Existing charge control systems for secondary battery modules struggle to accurately detect full charge levels due to voltage pulsations in unit cells, leading to incomplete charging and potential overcharge.
Innovation Solution
A charge control device with a constant voltage circuit using a Zener diode and resistor in series, connected to each unit cell, generates a pulse signal based on potential differences to determine full charge state, and a programmable controller adjusts charging power accordingly, effectively managing voltage pulsations and preventing overcharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage sampling is performed at specific timing to detect unit cell voltages, then the charge control can be executed, but the detected voltage becomes unstable due to voltage pulsation, leading to inaccurate full charge detection
Solution Approach 1:
The patent introduces a constant voltage circuit as an intermediary component between the unit cell and the detection system. This circuit converts the pulsating voltage into a stable signal that accurately reflects the full charge state, thereby resolving the contradiction between voltage detection and reliable full charge determination.
Solution Approach 2:
The patent applies preliminary action by detecting the full charge state through the constant voltage circuit before the voltage pulsation causes inaccurate readings. The system proactively determines charge status based on stable voltage thresholds rather than waiting for pulsating voltage measurements, ensuring reliable detection.
2Object-affected harmful factors
If the charge operation stops based on detected voltage to prevent overcharge, then overcharge prevention is achieved, but the battery may stop before full charge due to unstable voltage readings
Solution Approach 1:
The constant voltage circuit serves as a mediator that provides accurate full charge detection signals without being affected by voltage pulsation. This allows the charge control system to stop charging at the true full charge point, preventing both overcharge and premature termination, thus resolving the contradiction between safety and efficiency.
Solution Approach 2:
The patent implements feedback control where the charge operation is continuously monitored through the stable output of the constant voltage circuit. The system adjusts charging based on accurate real-time feedback about the full charge state, ensuring optimal balance between preventing overcharge and maximizing charging efficiency.
3Device complexity
If a simple voltage detection method is used, then the device complexity is low, but accurate full charge detection cannot be achieved due to voltage pulsation
Solution Approach 1:
The patent introduces a constant voltage circuit as an intermediary component between the unit cell and the detection system. This circuit converts the pulsating voltage into a stable signal that accurately reflects the full charge state, thereby resolving the contradiction between voltage detection and reliable full charge determination.
Solution Approach 2:
The patent changes the voltage parameter from pulsating to stable by introducing the constant voltage circuit. This transformation allows for precise full charge detection without requiring complex detection algorithms or multiple sampling points, maintaining simplicity while improving 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
Ensures accurate detection of full charge state in secondary battery modules, preventing overcharge and ensuring efficient charging to the maximum capacity while maintaining a compact and cost-effective battery charger design.
Implementation Method 1
a constant voltage circuit connected to both ends of each unit cell or each cell group and made up with a Zener diode and a resistor connected in series
Data Source
AI summary
A battery charger 2 equipped with an AC/DC converter charges a secondary battery module 1 constituted with a plurality of unit cells 10. The unit cells 10 are each connected in parallel with a constant voltage circuit 33 constituted with a Zener diode 332 and a resistor 331 connected in series, and the unit cell 10 achieving a state of full charge is detected based upon the difference between the potentials at the two sides of the resistor 331. As a battery controller 32 lowers the charging power used by the battery charger 2 in response to the full charge state being achieved, it is ensured that the secondary battery module 1 is charged thoroughly while preventing individual unit cells 10 from becoming overcharged.