Battery Pack Cell Balancing via Voltage Measurement
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Solution Overview
Problem
In battery packs, capacity deviations among cells due to manufacturing variations lead to over-charging and over-discharging, reducing the pack's capacity and shortening its lifespan, as cells in series or parallel connections experience uneven charge-discharge voltages.
Innovation Solution
A battery pack with a computer that measures open circuit voltages of individual cells and performs cell balancing by comparing these voltages to a standard, using a microcomputer to control charge and discharge devices to prevent over-charge and over-discharge, and balancing resistances to equalize cell voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a plurality of battery cells are connected in series or parallel to provide power, then the power output is improved, but capacity deviation among cells leads to over-charge and over-discharge
Solution Approach 1:
The patent applies local quality by implementing individual voltage measurement and balancing control for each battery cell. The computer measures the voltage of each cell separately and performs balancing operations on specific cells that deviate from the standard voltage, rather than treating all cells uniformly. This localized approach ensures that each cell maintains its voltage within acceptable ranges, preventing over-charge and over-discharge while maintaining high power output from the series/parallel configuration.
2Duration of action of stationary object
If cell balancing is performed by comparing voltages to standard value, then the battery pack lifespan is extended, but additional control circuitry and measurement systems are required
Solution Approach 1:
The patent implements self-service by enabling the battery pack to automatically monitor and balance its own cells through an integrated computer system. The computer continuously measures cell voltages, compares them against standard values, and autonomously performs balancing operations on cells that deviate from the standard voltage. This self-monitoring and self-balancing capability extends battery lifespan without requiring external intervention or complex manual control systems.
3Reliability
If voltage measurement and balancing control are implemented for each cell, then over-charge and over-discharge are prevented, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing a multi-functional computer system that integrates voltage measurement, comparison, and balancing control operations into a single device. The computer performs multiple functions: measuring cell voltages, comparing them to standard values, determining which cells require balancing, and controlling the balancing operations. This consolidated approach ensures reliable cell voltage stability without requiring separate dedicated circuits for each function, thereby reducing overall system complexity.
Data Source
AI summary
A battery pack and a method of controlling the same is disclosed. The battery pack determines a cell deviation after the battery pack is fully charged or over-discharged, and thus the battery pack can reduce the cell deviation by performing cell balancing.