Battery State Estimation Using Cell Voltage Balance Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems struggle to accurately estimate the state-of-charge (SOC) and state-of-health (SOH) of batteries, particularly due to voltage imbalances among cells, which can lead to overcharging, over-discharging, and reduced battery capacity.
Innovation Solution
A device and method that calculate the state-of-balance (SOB) by voltage of battery cells, allowing for accurate estimation of both SOC and SOH. This involves setting voltage difference allowable limits, calculating voltage drop rates, and deriving quantile degrees to apply a balance correction factor to the battery's health assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OCV-based SOC estimation is used, then the estimation process is simple, but it cannot accurately reflect the unbalanced voltage state of battery cells
Solution Approach 1:
The patent segments the battery system into individual cells and introduces a state-of-balance (SOB) metric that evaluates each cell's voltage deviation from the average. This segmentation allows the system to capture the unbalanced voltage state of individual cells while maintaining an overall SOC estimation framework, thereby improving measurement precision without excessive complexity.
Solution Approach 2:
The patent adds a new dimension to SOC estimation by introducing the SOB parameter that operates alongside traditional OCV-based methods. Instead of relying solely on average voltage, the system now considers the distribution of voltages across cells, adding a dimensional aspect that captures voltage balance information and improves estimation accuracy.
2Reliability
If voltage balance monitoring is implemented, then battery safety is improved, but the system complexity increases
Solution Approach 1:
The patent implements preliminary monitoring of voltage balance by continuously calculating the SOB parameter during battery operation. By detecting voltage deviations early through the SOB metric, the system can take preventive actions before dangerous imbalances occur, thereby improving reliability without requiring complex real-time intervention systems.
Solution Approach 2:
The patent introduces a feedback mechanism where the SOB parameter is continuously calculated and used to adjust the SOC estimation. This feedback loop allows the system to automatically respond to voltage imbalance conditions, improving battery safety through adaptive control rather than complex hard-wired protection circuits.
Data Source
AI summary
A device and method of estimating state-of-health of a battery is provided. A device of estimating a state-of-health (SOH) of a battery includes: a memory configured to load a program for calculating a state-of-balance (SOB) value by voltage of a plurality of cells constituting the battery and estimating a state-of-health balance value which is a state-of-health value of the battery to which the state-of-balance value by voltage is applied; and a processor configured to execute instructions included in the program loaded by the memory. A device and method of estimating state-of-charge of a battery is provided. A device of estimating state-of-charge (SOC) of a battery includes: a memory configured to load a program for correcting a voltage-to-remaining capacity correlation, in which a battery voltage is matched for each remaining capacity, based on a state-of-balance value by voltage of the battery; and a processor configured to execute instructions included in the program loaded in the memory.