Battery State Diagnosis Using Voltage-Range Capacity Ratios
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Solution Overview
Problem
Conventional lithium secondary batteries using lithium nickel-based oxides as positive electrodes do not meet the energy density requirements for applications like electric vehicles, and lithium-excess manganese-based oxides, while increasing capacity, suffer from gas generation and structural changes leading to deteriorated lifespan.
Innovation Solution
A battery management apparatus and method that calculates capacity ratios for each voltage range, compares them to reference ratios, and determines the state of the battery, including evaluating additional capacity due to positive electrode degradation, allowing for precise diagnosis and adjustment of usage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-excess manganese-based oxides are used as positive electrodes to increase capacity, then energy density is improved, but gas generation and structural changes occur leading to deteriorated lifespan
Solution Approach 1:
The battery management apparatus performs preliminary diagnosis by calculating capacity ratios for different voltage ranges before significant degradation occurs. By comparing the capacity ratio in the fourth voltage range (3.7V-4.2V) with reference values, the system detects early signs of positive electrode degradation and adjusts usage conditions proactively to prevent accelerated deterioration and extend battery lifespan.
2Measurement precision
If conventional battery management methods are used, then operation is simple, but precise diagnosis of battery state and degradation cannot be achieved
Solution Approach 1:
The battery management apparatus segments the battery voltage range into multiple ranges (first: 2.8V-3.2V, second: 3.2V-3.6V, third: 3.6V-4.0V, fourth: 4.0V-4.35V) and calculates capacity ratios for each segment. This segmentation enables precise diagnosis of battery state and positive electrode degradation by comparing the capacity ratio in the fourth voltage range with reference values, achieving high measurement precision through systematic division of the voltage range.
Data Source
AI summary
A battery management apparatus according to one embodiment of the present disclosure includes a storage unit configured to store battery information including a voltage and current, and a control unit configured to calculate a capacity ratio of a battery for each of a plurality of voltage ranges based on the battery information, to compare the calculated capacity ratio for each of the plurality of voltage ranges with a preset reference capacity ratio, and to determine a state of the battery based on a comparison result.