Battery State of Health Assessment via Relaxation Voltage Gradient
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Solution Overview
Problem
Existing methods for determining the state of health (SOH) of batteries in transportation devices are inaccurate and unreliable due to varying influencing factors, making it difficult to assess battery aging and extend service life effectively.
Innovation Solution
A method involving a charging process with a constant charge current to a predefined target voltage, followed by voltage measurements during a relaxation phase, where the difference or gradient between these measurements is used to ascertain the battery's state of health, ensuring comparable starting conditions and accurate SOH assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calculation models are used to determine SOH based on temperature and charge state, then the determination process is simple, but the accuracy and reliability of SOH assessment deteriorates
Solution Approach 1:
The patent extracts the battery from its normal operating state and places it in a controlled test state with constant current charging to a predefined voltage, followed by a relaxation phase. This isolation of the battery in a standardized test condition removes the influence of varying operating parameters and enables accurate SOH determination through voltage change measurement during relaxation, without requiring complex sensor systems.
Solution Approach 2:
The patent changes the operating parameters by applying a constant current charge to a predefined target voltage and then allowing a relaxation phase where current is reduced. This parameter change transforms the battery into a standardized test state, enabling accurate SOH assessment through voltage change measurement during relaxation, thereby resolving the contradiction between simplicity and accuracy.
2Reliability
If conventional SOH models are used that consider charge state and temperature, then the calculation process remains simple, but the reliability of SOH determination in certain operating states deteriorates
Solution Approach 1:
The patent performs preliminary actions by charging the battery to a predefined target voltage and then allowing a relaxation phase before measuring voltage changes. This preliminary standardization of the test state ensures that SOH determination is performed under consistent conditions, improving reliability across different operating states without requiring complex calculation models.
Solution Approach 2:
The patent creates a standardized test copy of the battery's operational state by applying constant current charging to a predefined voltage and then measuring voltage changes during relaxation. This standardized test state serves as a reliable reference that can be used consistently across different operating conditions, improving SOH determination reliability without increasing calculation model complexity.
3Measurement precision
If multiple charging processes are performed at different charge rates as described in US 2016/214500, then voltage increase profiles can be determined, but the time required for SOH estimation increases
Solution Approach 1:
The patent extracts only the essential measurement phase from the charging process by charging to a predefined target voltage and then measuring voltage changes during a relaxation phase. This eliminates the need for multiple charging processes at different rates, achieving accurate SOH estimation in a single charging cycle and significantly reducing the time required.
Solution Approach 2:
The patent skips the time-consuming multiple charging processes by directly charging to a predefined target voltage and immediately performing voltage measurements during relaxation. This rushing through to the essential measurement phase achieves accurate SOH estimation without the time loss associated with multiple charging cycles at different rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides a precise and reliable determination of the battery's state of health, allowing for early recognition of aging and extending the battery's service life by ensuring consistent and accurate assessments.
Implementation Method 1
a first voltage value of the battery is ascertained at a first predefined point in time after the predefined target voltage has been reached in a relaxation phase of the battery
Data Source
AI summary
A method and to a device for ascertaining a state of health of a battery for a transportation device. The method includes: charging the battery until a predefined target voltage is reached in a first charging phase of the battery, ascertaining a first voltage value of the battery at a first predefined point in time after the predefined target voltage has been reached in a relaxation phase of the battery, ascertaining a second voltage value of the battery at a second predefined point in time, deviating from the first predefined point in time, in the relaxation phase of the battery, ascertaining a piece of information about the state of health of the battery based on a change of the second voltage value with respect to the first voltage value, and using the piece of information in the transportation device and/or in an external server.