Secondary Battery Internal Temperature Estimation Using Equivalent Circuit
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Solution Overview
Problem
Existing methods for estimating the internal temperature of secondary batteries are inaccurate when the battery type changes or degrades, as they do not account for variations in temperature characteristics due to different types or states of degradation.
Innovation Solution
A secondary battery internal temperature estimation device and method that use an equivalent circuit model with solution resistance, reaction resistance, and electric double layer capacity, determining coefficients based on these elements and dischargeable capacity, and applying them to a relational equation to estimate internal temperature, regardless of battery type or degradation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature estimation techniques are used, then the estimation is simple and quick, but the accuracy deteriorates when battery type changes or degradation occurs
Solution Approach 1:
The patent changes the parameters used for temperature estimation from simple conventional parameters to equivalent circuit element values (solution resistance, reaction resistance, electric double layer capacity) that inherently reflect battery type and degradation state. By using these changed parameters in the relational equation, the system achieves accurate temperature estimation across different battery types and degradation levels without increasing system complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the estimation system uses calculated equivalent circuit element values to determine coefficients for the relational equation. This feedback loop ensures that the temperature estimation automatically adapts to different battery types and degradation states, maintaining high accuracy without requiring manual intervention or complex system reconfiguration.
2Adaptability or versatility
If a fixed relational equation is used for temperature estimation, then the system is simple to operate, but it cannot adapt to different battery types or degradation states
Solution Approach 1:
The patent makes the relational equation dynamic by automatically determining its coefficients based on calculated equivalent circuit element values. This dynamic adaptation allows the system to handle different battery types and degradation states without requiring manual reconfiguration or complex user input, maintaining ease of operation while achieving high adaptability.
Solution Approach 2:
The estimation system performs self-service by automatically determining the appropriate coefficients for the relational equation based on the calculated equivalent circuit parameters. This self-determination mechanism enables the system to adapt to different battery types and degradation states without external intervention, combining adaptability with operational simplicity.
Data Source
AI summary
A secondary battery internal temperature estimation device that estimates a secondary battery's internal temperature regardless of the secondary battery's type or state of degradation, the device including: a control unit that estimates the secondary battery's internal temperature on the basis of a relational equation showing a relationship between an external temperature and the secondary battery's internal temperature. A control unit calculates element values of an equivalent circuit of the secondary battery, determines a coefficient of the relational equation on the basis of the element values of the equivalent circuit calculated by the control unit, and applies the coefficient obtained by the control unit to the relational equation. The control unit estimates the secondary battery's internal temperature on the basis of the relational equation to which the coefficient has been applied by the control unit.