Battery Internal Temperature Estimation Using Admittance and Surface Heat
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Solution Overview
Problem
Existing methods for estimating the internal temperature of batteries in new energy vehicles lack precision due to not considering the real-time charging and discharging states and measure the average temperature instead of the actual internal temperature, leading to inaccurate estimations.
Innovation Solution
A battery temperature estimation method that fits a first function relationship to corresponding admittances at different test temperatures and uses a temperature distribution model to determine a second function relationship between internal and surface temperatures, allowing for precise internal temperature estimation using real-time admittances and surface temperature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional impedance-based methods are used to estimate battery internal temperature, then the measurement process is simple, but the estimation precision is low because the effect of real-time charging and discharging states is not considered
Solution Approach 1:
The patent applies preliminary action by pre-establishing a temperature distribution model offline that incorporates the effects of charging and discharging states. During online operation, the system only needs to measure admittance and apply the pre-computed model, avoiding real-time complex calculations while maintaining high precision internal temperature estimation
Solution Approach 2:
The patent uses admittance as an intermediary parameter to bridge the relationship between battery state and temperature. By measuring admittance and using it as input to the temperature distribution model, the system indirectly obtains accurate internal temperature without directly measuring it, resolving the contradiction between simplicity and precision
2Measurement precision
If average temperature measurement is used, then the measurement process is simple, but the internal temperature accuracy is insufficient because it represents the entire battery rather than the actual internal temperature
Solution Approach 1:
The patent replaces direct physical temperature measurement (mechanical/thermal sensing) with electrical admittance measurement combined with a computational model. By substituting the physical measurement approach with an electrical measurement and mathematical modeling approach, the system achieves accurate internal temperature estimation without the complexity of internal sensors
Solution Approach 2:
The patent changes the measurement parameter from direct temperature sensing to admittance measurement. By measuring electrical admittance and transforming it through the temperature distribution model, the system obtains accurate internal temperature information while avoiding the difficulties of direct internal temperature measurement
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 significantly improves the precision of internal temperature estimation by considering the battery's shape, size, and real-time charging and discharging states, providing a more accurate representation of the internal temperature compared to traditional methods.
Implementation Method 1
the internal temperature of the power battery of the new energy vehicle is estimated by obtaining a relationship between feature quantities of electrochemical impedance spectroscopy and an ambient temperature
Implementation Method 2
the obtained internal temperature is actually the average temperature of the entire battery rather than the actual temperature inside the battery
Data Source
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AI summary
Provided are a battery temperature estimation method and apparatus, an electronic device, and a storage medium, which relate to the field of battery technologies. The method includes: fitting, when a battery is in an offline state, a first function relationship according to corresponding admittances of the battery at different test temperatures; and obtaining a temperature distribution model of the battery according to the shape and the size of the battery, and determining a second function relationship corresponding to internal temperatures and a surface temperature by combining with the first function relationship, the second function relationship being used for estimating the internal temperature of the battery by using the surface temperature and the admittances of the battery.