Battery Impedance Detection via Frequency Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In battery systems, especially those for hybrid/electric vehicles, accurately monitoring the State of Health (SoH) and State of Charge (SoC) of series-connected batteries is challenging due to limited bandwidth, requiring efficient communication and processing of significant data while maintaining reliable charge and discharge strategies for enhanced battery life and energy storage.
Innovation Solution
The method involves separating low-frequency and high-bandwidth impedance components of battery cells, communicating low-frequency components for all cells and a subset of high-bandwidth components based on available bandwidth, using current injection circuits and filtering to optimize data transmission, and employing cell balancing circuits for accurate impedance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If all impedance data components are communicated for accurate SoH and SoC determination, then measurement precision is improved, but communication bandwidth requirements increase
Solution Approach 1:
The patent segments impedance data into low-frequency components and high-bandwidth components, communicating low-frequency data for all cells and selectively communicating high-bandwidth data for subsets of cells based on available communication bandwidth. This segmentation allows accurate SoH determination (requiring low-frequency data) while managing communication constraints through selective transmission of high-bandwidth data.
Solution Approach 2:
The patent applies different communication strategies to different frequency components of impedance data. Low-frequency components are communicated for all battery cells to enable accurate SoH determination, while high-bandwidth components are communicated selectively for subsets of cells based on communication bandwidth availability. This local quality approach optimizes the balance between measurement precision and communication requirements.
2Measurement precision
If high-bandwidth impedance components are communicated for all cells, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides impedance data into frequency-based segments (low-frequency and high-bandwidth components) and implements selective communication of high-bandwidth data for subsets of cells. This segmentation reduces the overall data processing burden and communication system complexity while maintaining the precision needed for accurate impedance measurement and SoH determination.
3Reliability
If complete impedance data is processed for all cells, then reliability of battery monitoring is improved, but loss of time in data communication increases
Solution Approach 1:
The patent segments impedance data into low-frequency components (communicated for all cells) and high-bandwidth components (communicated selectively for subsets of cells). This segmentation enables reliable battery monitoring by ensuring low-frequency data is always communicated while reducing communication time through selective transmission of high-bandwidth data based on available bandwidth and monitoring priorities.
Solution Approach 2:
The patent implements periodic communication of high-bandwidth impedance data for subsets of battery cells based on available communication bandwidth. This periodic action allows the system to balance reliable monitoring (through regular low-frequency data communication) with reduced communication time (through selective high-bandwidth data transmission at appropriate intervals).
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
This approach effectively reduces data communication bandwidth, ensures reliable SoH and SoC determination, and enhances battery life and energy storage capacity by tailoring data communication to available bandwidth and selectively providing high-bandwidth data only when necessary.
Implementation Method 1
impedance characteristics are detected for a plurality of battery cells in a battery pack
Implementation Method 2
a filter circuit is coupled to the impedance-detection circuit to separate low-frequency components of data regarding the detected impedance characteristics from high-bandwidth components of the data regarding the detected impedance characteristics
Data Source
Figure 1
Figure 2
AI summary
Various aspects of the present disclosure are directed to monitoring battery cells. In accordance with various embodiments, an energy storage cell apparatus includes a current injection circuit that separately inject current into individual ones of a plurality of battery cells that store energy, and an impedance-detection circuit detects an impedance characteristic of each of the plurality of battery cells in response to the injected current. A filter circuit receives impedance data regarding the detected impedance characteristic and separates low-frequency components of the impedance data from high-frequency components of the impedance data. A memory circuit stores data corresponding to high-bandwidth data including both the low-frequency components and the high-frequency components, and an access circuit provides the low-frequency components for the plurality of battery cells to a battery pack controller. The access circuit further accesses and provides the stored high-bandwidth data for a subset of the individual battery cells to the battery pack controller based upon available bandwidth for communicating the high-bandwidth data.