Battery Management System Temperature Segmentation
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Solution Overview
Problem
Battery management systems face challenges in maintaining optimal charge and discharge control across varying temperatures and states of charge among individual cells in a combined battery, leading to potential overcharge or overdischarge, which accelerates battery deterioration.
Innovation Solution
A battery management system comprising temperature and voltage/current measuring units, a calculation unit to determine maximum and minimum temperatures/voltages, and a selection unit to choose the smallest available charge/discharge powers/currents, with an optional limiter unit to adjust powers/currents based on battery voltage limits, ensuring optimal control across temperature and SOC variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If charge and discharge control is performed based on average battery temperature, then overall battery management is simplified, but temperature variations among individual single cells cause inaccurate power limiting and potential overcharge/overdischarge
Solution Approach 1:
The patent divides the battery into multiple temperature zones by placing temperature detectors at different positions (e.g., upper, middle, lower portions) of individual single cells. This segmentation allows each zone's temperature to be measured independently, enabling accurate identification of the maximum temperature among all cells without requiring a single complex average calculation, thus resolving the contradiction between simplified management and accurate control.
Solution Approach 2:
The system performs preliminary temperature measurement and comparison across all single cells before determining charge/discharge power limits. By pre-identifying the maximum temperature among all cells and using it to set appropriate power limits in advance, the system ensures accurate control is established before charging or discharging begins, preventing overcharge/overdischarge while maintaining manageable system complexity.
2Productivity
If charge and discharge power limits are set based on maximum available power at each temperature, then optimal power utilization is achieved, but SOC variations among single cells lead to inconsistent actual available power
Solution Approach 1:
The patent segments the power limitation process by separately determining charge power limits and discharge power limits based on different temperature conditions. For each single cell, the system identifies its maximum temperature, determines the corresponding maximum available charge/discharge power from stored data, and selects the minimum value across all cells as the overall power limit. This segmented approach ensures both optimal power utilization and accuracy despite SOC variations.
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring actual battery temperatures during operation and comparing them against the predetermined maximum temperatures used to set power limits. This feedback allows the system to adjust power delivery dynamically, ensuring that the power limits remain accurate and reliable even when SOC variations occur among single cells, while maintaining high power utilization efficiency.
3Productivity
If higher power is extracted from batteries at higher temperatures, then energy output is maximized, but battery deterioration accelerates
Solution Approach 1:
The patent applies parameter changes by establishing a temperature-dependent power limit strategy. The system stores maximum available charge/discharge power values corresponding to different maximum temperatures observed among single cells. When the maximum temperature exceeds a predetermined threshold, the system automatically selects lower power limits from the stored data, thereby reducing power extraction at high temperatures to extend battery lifespan while still maximizing energy output when temperatures are lower and safer.
Data Source
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AI summary
The present invention relates to a battery management system which can output a battery state enabling optimum charge and discharge control to be performed even when a temperature variation occurs among individual single cells. A plurality of temperature sensors (20x1, 20x2, 20n1, 20n2) measure temperature values of a battery (10). A measurement unit (30) measures a voltage and a current of the battery (10). A maximum/minimum temperature selection unit (102) in a calculation unit (100) determines a maximum temperature (Tmax) and a minimum temperature (Tmin.) from the temperature values measured by the temperature sensors (20x1, 20x2, 20n1, 20n2). An available power calculation unit (104) calculates respective values of maximum available charge and discharge powers Pcmax, Pdmax) or maximum available charge and discharge currents of the battery (10) corresponding to the maximum temperature (Tmax) and the minimum temperature (Tmin) based on the voltage and the current of the battery (10). A selection unit (110) selects and outputs smaller maximum available charge and discharge powers or smaller maximum available charge and discharge currents from the respective values of the maximum available charge and discharge powers or the maximum available charge and discharge currents (Icmax, Idmax) of the battery (10) corresponding to the maximum temperature (Tmax) and the minimum temperature (Tmin), which are calculated by the calculation unit (100).