Battery Status Estimation via Parallel Impedance Measurement
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Solution Overview
Problem
Energy storage systems, such as MESDCS and RBS, face challenges in efficiently managing the status of individual energy storages, particularly in determining the state of health and power capability, which affects overall system performance and longevity due to the cascaded structure causing additional harmonic stress on battery cells.
Innovation Solution
The system employs a control mechanism with voltage and current sensors to selectively connect energy storages in series, parallel, or bypass states, allowing for impedance measurement by connecting two energy storages in parallel to determine the status parameter, such as impedance, using time-dependent voltage-current characteristics, and potentially leveraging machine learning algorithms for rapid parameter estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual battery cells are monitored for status parameters, then the state of health and power capability can be determined, but additional measurement hardware and system complexity are required
Solution Approach 1:
The patent makes the energy storage elements serve dual functions: both as power sources and as measurement devices. By utilizing the inherent voltage and current characteristics during normal operation and parallel connection events, the system extracts status parameters without dedicated measurement hardware for each cell, thus achieving multi-functionality that resolves the contradiction between measurement precision and device complexity
Solution Approach 2:
The system uses the battery cells themselves to provide measurement information. When cells are connected in parallel, the natural current flow and voltage differences between cells provide the data needed for status parameter estimation, eliminating the need for external measurement devices and reducing system complexity while maintaining measurement accuracy
2Measurement precision
If parallel connection of energy storages is used for status parameter determination, then impedance can be measured, but additional current meters and switching control are required
Solution Approach 1:
The switching arrangement, originally designed for power management and balancing operations, is repurposed to also perform measurement functions. The same switches that control power flow are used to configure parallel connections for impedance measurement, eliminating the need for separate measurement circuitry and reducing overall device complexity while maintaining measurement precision
Solution Approach 2:
The patent merges the power management function and measurement function into a single integrated system. The switching arrangement simultaneously handles both operational control and parameter measurement, combining what could be separate systems into one unified structure, thereby reducing complexity while achieving accurate impedance measurement
3Stability of the object's composition
If conventional battery packs with hardwired connections are used, then structural stability is maintained, but individual cell replacement and impedance measurement are difficult
Solution Approach 1:
The patent segments the battery system into modular energy storage elements with standardized interfaces. This segmentation allows individual cells or modules to be independently replaced while maintaining the overall structural stability of the battery pack. The modular design with switching arrangements enables easy reconfiguration and replacement without affecting the hardwired connections of other cells, thus resolving the contradiction between structural stability and ease of repair
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 enables precise estimation of energy storage status parameters with minimal additional hardware, allowing for optimized operation by prioritizing healthier cells and reducing overall system stress, thereby extending the lifespan of the energy storage system.
Implementation Method 1
determining the status parameter, in particular the impedance, based on a time-dependent voltage-current-characteristic
Data Source
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AI summary
Disclosed herein are energy storage systems comprising cascaded energy storages, at least some of which being formed by battery cells or battery packs, and a switching arrangement allowing for establishing selected connection states of said energy storages. Control systems and methods allowing for determining a status parameter of individual energy storages in said energy storage systems are likewise disclosed. In one embodiment, the status parameter is determined based on a current flow into or out of a given energy storage when the given energy storage is connected in parallel with another energy storage. In another embodiment, the status parameter is determined using electrochemical impedance spectroscopy, wherein part of the energy storage system and part of an electrical consumer are used for generating an AC current injected into a given energy storage.