Adaptive Battery State Measurement via Electrochemical Model Switching
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Solution Overview
Problem
Existing battery state measurement methods lack accuracy in distinguishing between low and high rate operational modes, which affects the precise estimation of battery state of charge (SOC) and health (SOH), particularly when batteries operate under varying conditions such as different current rates, voltages, and temperatures.
Innovation Solution
A method and apparatus that determine the operational mode of a battery using current rate (C-rate) and voltage values, employing either an electrochemical model or a modified electrochemical model based on concentration overvoltage to measure battery state, with a controller utilizing Butler-Volmer's equations to calculate electrochemical reaction amounts and potential information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single electrochemical model is used for all operational modes, then the model structure remains simple, but measurement precision deteriorates under high rate modes due to concentration overvoltage effects
Solution Approach 1:
The patent applies dynamics by making the electrochemical model adaptive - it dynamically switches between a standard electrochemical model for low rate modes and a modified electrochemical model with concentration overvoltage terms for high rate modes. This dynamic adaptation allows the system to maintain measurement precision across varying operational conditions without permanently increasing model complexity.
Solution Approach 2:
The patent changes model parameters based on operational mode detection. When high rate mode is detected (C-rate ≥ threshold), the system activates the modified electrochemical model that includes concentration overvoltage parameters. This parameter change approach enables accurate measurement under different conditions while keeping the base model structure relatively simple.
2Measurement precision
If operational mode determination uses multiple parameters (C-rate, voltage, temperature), then measurement precision improves, but device complexity increases due to additional sensors and calculations
Solution Approach 1:
The controller serves multiple functions: it monitors battery operation, determines operational modes, selects appropriate electrochemical models, and calculates battery state. By making the controller multi-functional, the patent avoids adding separate dedicated hardware for mode determination, thus improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The system performs preliminary determination of operational mode using readily available battery parameters (current, voltage, temperature) before selecting the appropriate electrochemical model. This preliminary action allows the system to prepare the correct measurement approach in advance, improving accuracy without requiring complex real-time decision-making hardware.
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
Enhances the accuracy of battery state measurement by adapting to different operational modes, improving the estimation of SOC and minimizing degradation through precise determination of electrochemical reactions, especially in high rate modes where concentration overvoltage is significant.
Implementation Method 1
measuring the battery state using a Butler-Volmer's equation for determining an electrochemical reaction amount on an interface between an electrode and an electrolyte
Implementation Method 2
measuring the battery state using a modified electrochemical model based on concentration of the battery
Data Source
AI summary
Disclosed is a method and apparatus for measuring a battery state. The method includes determining an operational mode of a battery; measuring a battery state of the battery using an electrochemical model in response to the battery determined to be operating in a low rate mode, and measuring the battery state using a modified electrochemical model based on a characteristic of the battery, in response to the battery determined to be operating in a high rate mode.