Battery Pack SOC Estimation Using Cell Voltage and Temperature
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Solution Overview
Problem
Traditional battery management systems are inadequate for high voltage battery packs, as they cannot accurately monitor and respond to the varying states of individual cells due to differences in internal resistance and capacity, leading to reduced safety and lifetime.
Innovation Solution
A battery management system comprising a temperature sampling circuit, voltage measurement circuits, and a microcontroller that calculates the present battery powers of multiple battery packs by obtaining temperature, open circuit voltage, and current parameters, enabling precise state-of-charge estimation and real-time protection mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple cells are connected in series to increase terminal voltage for high voltage battery packs, then the battery pack can meet the rated voltage required by the load, but the terminal voltage of individual cells may exceed or fall below threshold voltage due to differences in internal resistance and capacity
Solution Approach 1:
The patent divides the battery pack into multiple individual cell units, each with its own monitoring and management. The system separately tracks the state of charge, temperature, and voltage of each cell, enabling independent protection and management of each segment rather than treating the battery pack as a single unit.
Solution Approach 2:
The patent implements real-time feedback mechanisms by continuously monitoring cell voltage, current, and temperature parameters. The system uses this feedback to dynamically adjust charging/discharging rates and provide immediate protection when cells approach threshold values, enabling responsive control based on actual battery state.
2Device complexity
If traditional battery management systems monitor only single cell or use specific series/parallel connections, then the system structure is simple, but the system cannot perform accurate response based on instantaneous state of each cell in high voltage battery packs
Solution Approach 1:
The patent implements individual monitoring for each cell in the battery pack, with separate measurement circuits and control logic for each cell. This segmented approach allows precise tracking of each cell's state of charge, temperature, and voltage without requiring complex inter-cell connections.
Solution Approach 2:
Each cell is equipped with its own monitoring and protection mechanisms, allowing the battery management system to independently assess and protect each cell based on its specific state. The system performs self-diagnosis and automatic protection without requiring external intervention or complex centralized control.
Data Source
AI summary
A battery management system and a battery management method are provided. The battery management system includes a temperature sampling circuit, a plurality of voltage measurement circuits, a current sampling circuit, and a microcontroller. The temperature sampling circuit is configured to obtain a temperature parameter of a plurality of battery packs. The voltage measurement circuits are configured to obtain a plurality of open circuit voltage parameters of the battery packs. The current sampling circuit is configured to obtain a current parameter of the battery packs. The microcontroller obtains a plurality of initial state-of-charge parameters of the battery packs according to the open circuit voltage parameters and the temperature parameter and respectively calculates a plurality of present battery powers of the battery packs according to the initial state-of-charge parameters, the temperature parameter, and the current parameter.