Battery SOH Estimation Using OCV-SOC Capacity Variation
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Solution Overview
Problem
Existing methods for estimating the state of health (SOH) of lithium-ion power batteries in electric vehicles are inaccurate due to variations in temperature and usage conditions, leading to incorrect estimation of state of charge (SOC) and driving range, which affects user experience.
Innovation Solution
A method using the Open Circuit Voltage (OCV)-State of Charge (SOC) curve to identify specific SOC points and calculate capacity variation, converting it into a percentage of nominal capacity to determine SOH, without relying on cycle number correlations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple pieces of information are collected to accurately reflect battery state, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The detection device is designed to perform multiple functions: it detects battery terminal voltage, acquires battery temperature, calculates state of charge, and determines state of health. By integrating these multiple detection capabilities into a single unified device, the patent achieves comprehensive battery state monitoring without proportionally increasing device complexity.
Solution Approach 2:
The detection device acts as an intermediary between the battery and the control unit. It collects multiple parameters (voltage, temperature), processes them through calculation modules (state of charge calculation, state of health determination), and provides processed information to the control unit, thereby simplifying the overall system architecture while maintaining high measurement precision.
2Quantity of substance
If battery is charged to higher state of charge to increase energy storage, then energy capacity is improved, but battery reliability deteriorates due to aging and safety risks
Solution Approach 1:
The patent implements a feedback mechanism where the detection device continuously monitors battery parameters (voltage, temperature) and calculates state of charge and state of health. This information is fed back to the control unit, which adjusts charging strategies in real-time. When the battery approaches high state of charge or shows signs of degradation, the system automatically adjusts charging parameters to prevent safety issues and reduce aging, thus maintaining reliability while maximizing energy storage.
Solution Approach 2:
The charging strategy is made dynamic rather than static. The control unit adjusts charging current and voltage based on real-time battery conditions (temperature, state of charge, state of health). This dynamic adjustment allows the battery to operate at high energy capacity when conditions permit, while automatically reducing stress on the battery when approaching safety limits or when aging is detected, thereby resolving the contradiction between energy storage and reliability.
Data Source
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AI summary
The embodiments of the disclosure relate to a method and device for acquiring a state of health of a battery, and a storage medium. when a vehicle is powered on, determining whether a capacity variation calculation condition is satisfied; when determining that the capacity variation calculation condition is satisfied, calculating a capacity variation; when the vehicle is powered on, determining whether a capacity calculation condition is satisfied; when determining that the capacity calculation condition is satisfied, calculating a capacity; and calculating the state of health of the battery according to the capacity variation and the capacity. According to the method, the device and the storage medium of the embodiments of the disclosure, it is not necessary to measure a corresponding relation between a cycle number during a life cycle of the battery and the SOH, thus saving test resources and time; an aging degree of the actual capacity of the battery is more truly reflected, an estimation accuracy of a state of charge and a driving range is improved, and a good driving experience is provided for users.