Cell-Level Battery Protection Circuit for Parallel Cell Imbalance
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Solution Overview
Problem
Existing techniques for protecting rechargeable batteries with multiple cells connected in parallel do not adequately prevent overcharging and overdischarging, particularly when cells have different capacities or voltage differences, leading to potential damage and inefficiencies.
Innovation Solution
A battery protection circuit and method that includes overcharging and overdischarging detection, charging and discharge current limiting, and control devices for each cell, using transistors and integrated circuits to manage currents and prevent excessive charging or discharging, while allowing controlled current flow based on cell potential differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple cells are connected in parallel to increase battery capacity, then the battery can store more energy, but cells with different capacities or voltage differences can cause inrush currents and overcharging/overdischarging issues
Solution Approach 1:
The patent divides the battery system into individual cell protection units, with each cell having its own detection and control circuitry. This segmentation allows independent monitoring and control of each cell's charging and discharging processes, preventing harmful current flow between cells with different states while maintaining overall battery functionality.
Solution Approach 2:
The patent introduces protection circuits as intermediary components between cells with different capacities or voltage levels. These circuits detect potential harmful conditions and control current flow, acting as mediators that prevent direct harmful interactions between mismatched cells while allowing them to operate together in parallel.
2Adaptability or versatility
If cells with different capacities are connected in parallel, then battery assembly flexibility increases, but voltage differences cause inrush currents during charging
Solution Approach 1:
The protection circuit performs preliminary detection of cell voltage and current states before harmful inrush currents can develop. By detecting potential overcharging conditions in advance and controlling current flow proactively, the system prevents inrush currents from occurring while maintaining the ability to connect cells with different capacities.
3Measurement precision
If individual cell protection circuits are implemented, then cell-level protection accuracy improves, but circuit complexity increases
Solution Approach 1:
The patent designs protection circuits that perform multiple functions: detecting overcharging, controlling charging current, preventing inrush currents, and managing discharge protection. By making each protection circuit multi-functional, the system achieves high detection accuracy and comprehensive protection without proportionally increasing overall system complexity.
Data Source
AI summary
A battery protection circuit that protects a rechargeable battery including cells connected in parallel includes an overcharging detection part provided for each of the cells and configured to prevent the corresponding cell from being charged in response to detecting overcharging of the corresponding cell, an overdischarge detection part provided for each of the cells and configured to prevent the corresponding cell from being discharged in response to detecting overdischarge of the corresponding cell, a charging current limiting part provided for each of the cells and configured to prevent a charging current from exceeding a predetermined charging current value during a period for which the charging current flows through the corresponding cell, and a discharge current limiting part provided for each of the cells and configured to prevent a discharge current from exceeding a predetermined discharge current value during a period for which the discharge current flows through the corresponding cell.