EV Battery Impedance Modeling for Aging-Aware Power Limits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems struggle to accurately capture all relevant operations, such as aging, due to time-intensive model development and limitations in traditional electrochemical impedance spectroscopy methods, leading to potential battery degradation and thermal runaway risks.
Innovation Solution
A battery impedance model that associates battery impedance values with frequency-dependent polarization impedance values to characterize diffusion states, enabling precise control and monitoring of battery packs by using a battery management module to define power limits based on low frequency impedance behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrochemical impedance spectroscopy methods are used to monitor battery operations, then measurement capability is provided, but time-intensive model development and inaccurate capture of aging processes occur
Solution Approach 1:
The patent transforms the battery impedance model from static to dynamic by introducing frequency-dependent polarization impedance values that change with diffusion states. This allows the model to adapt to varying battery conditions (charging, discharging, aging) without requiring redevelopment, thereby improving measurement precision while avoiding time loss.
Solution Approach 2:
The patent implements a dynamic battery impedance model that continuously updates polarization impedance values based on real-time diffusion states. This dynamic approach enables accurate tracking of battery aging processes without requiring time-intensive remodelling, as the system automatically adjusts to changing operational conditions.
2Manufacturing precision
If frequency-dependent polarization impedance values are used to represent diffusion states, then battery control precision is improved, but system complexity increases
Solution Approach 1:
The patent introduces polarization impedance values as an intermediary parameter that bridges the relationship between diffusion states and battery power limits. This intermediary simplifies the control process by providing a direct measurable parameter that reflects diffusion states, improving control precision without proportionally increasing system complexity.
Solution Approach 2:
The battery impedance model serves multiple functions simultaneously: it characterizes diffusion states, determines power limits, monitors aging processes, and controls charge/discharge operations. This multi-functionality achieves high control precision while avoiding the need for separate complex systems for each function.
3Reliability
If battery impedance model is used to define power limits, then battery safety is improved, but computational requirements increase
Solution Approach 1:
The patent pre-establishes the relationship between polarization impedance values and diffusion states in the battery impedance model. This preliminary modeling allows the system to quickly determine power limits during operation without performing complex real-time calculations, thereby improving battery safety while minimizing computational energy consumption.
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
Accurately controls battery power and energy delivery, tracks aging, and prevents degradation by modeling diffusion processes, thereby enhancing safety and efficiency.
Implementation Method 1
The battery impedance model associates battery impedance values with frequency-dependent polarization impedance values representing diffusion states of the battery cells
Data Source
AI summary
An electrified vehicle (EV) includes a battery pack, one or more sensors, and a vehicle controller. The battery pack includes a plurality of battery cells and is operable to provide at least a portion of propulsion power. The vehicle controller is configured to charge and discharge the battery pack according to power limits defined by output of a battery impedance model. The battery impedance model associates battery impedance values with frequency-dependent polarization impedance values representing diffusion states of the battery cells, and receives measured parameters from the one or more sensors indicative of the frequency-dependent polarization impedance values of the battery pack.