Li-Ion Battery Electrochemical Models for Fast Terminal Voltage Estimation
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Solution Overview
Problem
Existing battery management systems face challenges in accurately and efficiently estimating the terminal voltage and state of lithium-ion batteries due to the high computational complexity of physics-based electrochemical models, which limits their practical application in real-time battery management and optimization.
Innovation Solution
The development of reduced-order, physics-based electrochemical models, such as the revised single-particle model (RSPM) and fast-calculating pseudo-two-dimensional model (FCP2D), that represent lithium-ion concentration and electrolyte potential distributions using polynomial functions, coupled with side-reaction mechanisms, to enhance simulation efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physics-based electrochemical models (P2D model) are used to estimate battery terminal voltage and state, then measurement precision and reliability are improved, but device complexity and computational requirements increase significantly
Solution Approach 1:
The patent transforms the complex partial differential equations of the P2D model into polynomial equations by parameterizing the lithium-ion concentration and electrolyte potential distributions. This changes the mathematical parameters from continuous spatial functions to discrete polynomial coefficients, reducing computational complexity while maintaining accuracy
Solution Approach 2:
The patent creates simplified polynomial function copies of the original electrochemical model equations. These polynomial approximations replicate the behavior of the full P2D model but can be evaluated much faster, enabling real-time battery management system applications
2Measurement precision
If rigorous physical models are used to capture reaction kinetics, then measurement precision is improved, but productivity and real-time performance deteriorate
Solution Approach 1:
The patent changes the computational parameters from solving differential equations at each time step to evaluating polynomial expressions with pre-determined coefficients. This parameter transformation enables rapid calculation while preserving the physical accuracy of reaction kinetics
Solution Approach 2:
The patent performs preliminary calculations to determine the polynomial coefficients offline or during model setup. By pre-computing these parameters, the model eliminates the need for iterative numerical solutions during real-time operation, significantly improving calculation speed
Data Source
AI summary
An electrical device can comprise: a battery including one or more electrochemical cells; a temperature sensor positioned in at least one of the electrochemical cells; a current sensor for measuring a current flowing from the battery; and a battery management system including a controller in electrical communication with the temperature sensor and the current sensor. The controller is configured to execute a program to: (i) calculate a terminal voltage of the battery using an electrochemical model that receives as inputs a temperature reading from the temperature sensor and the current flowing from the battery and outputs the terminal voltage of the battery, wherein the electrochemical model calculates the terminal voltage of the battery using a lithium-ion concentration distribution as a first polynomial function and an electrolyte potential distribution as a second polynomial function, and (ii) determine a state of the battery based on the terminal voltage.