Real-time Battery Cell Simulation via Reference and Deviation Models
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Solution Overview
Problem
Existing methods for simulating battery cells in Hardware-in-the-Loop (HIL) testing struggle with real-time capability when dealing with a large number of individual cells, leading to increased computing time and memory usage, which hinders the ability to test control units effectively.
Innovation Solution
A method utilizing an overall model on a computing unit connected to a control unit system via a cell voltage emulator, where the terminal voltages of individual cells are calculated using a reference model and a difference model, reducing computing effort and optimizing memory usage by simplifying the simulation of cell assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual cell models are used for each cell in a large cell assembly, then the simulation accuracy and individual cell parameter adjustability are improved, but the computing time and memory usage increase significantly, losing real-time capability
Solution Approach 1:
The patent segments the simulation model into two parts: a reference model that captures typical cell assembly behavior, and individual cell deviation models that capture specific cell variations. This segmentation allows the system to maintain real-time capability while preserving individual cell characteristics needed for BMS testing.
Solution Approach 2:
The patent merges the reference model with individual cell deviation models to create an overall model. The reference model provides the baseline behavior for the entire cell assembly, while individual deviations are superimposed to account for parameter spreads and different charge states, achieving both accuracy and efficiency.
2Adaptability or versatility
If individual cell models are used for each cell in a large cell assembly, then the individual cell parameter adjustability and charge state differentiation are improved, but the device complexity and handling difficulty increase
Solution Approach 1:
The model is segmented into a reference component and individual deviation components. This allows the system to maintain individual cell parameter adjustability through the deviation models while keeping the overall structure manageable through the unified reference model framework.
Solution Approach 2:
The reference model serves as a universal baseline that applies to all cells in the assembly, while individual deviation models provide specific adjustments. This multi-functional approach allows the same modeling framework to handle both typical behavior and individual variations efficiently.
3Adaptability or versatility
If the number of individual cells in the simulation is increased, then the representation of parameter spreads and different charge states is improved, but the real-time capability is lost due to increased computing requirements
Solution Approach 1:
By segmenting the simulation into a reference model handling common behavior and individual deviation models handling specific variations, the system can represent parameter spreads and different charge states across many cells without proportionally increasing computing complexity, thus maintaining real-time capability.
Solution Approach 2:
The patent changes the modeling approach from simulating each cell's complete behavior to simulating deviations from a reference state. This parameter transformation allows efficient handling of multiple cells with different parameters and charge states while maintaining real-time performance.
Data Source
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AI summary
The method involves providing several individual cells that are interconnected with each other, a battery for simulation purpose described by an overall model based on an arithmetic unit, and a first model which models a reference cell (EMK) and with which the terminal voltage of the reference cell is calculated. A second model with which the deviation of terminal voltage of each other cell and the terminal voltage of the reference cell is calculated based on the reference terminal voltage and derived values of terminal voltages of each cell, is provided.