Modular Battery Management System for Cell Balancing and SoH Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current battery management systems face challenges in efficiently balancing voltage and capacity of rechargeable energy storage cells, leading to energy and heat loss, and require complex and costly active balancing circuits, while SoH estimation methods are either inefficient or inaccurate, often requiring long testing times and additional components.
Innovation Solution
A modular management system using bidirectional and unidirectional switches connected to a single ohmic device, such as a resistor, to perform passive/active balancing and SoH/SoC estimation without external components, enabling a Dual Function Process (DFP) for efficient energy storage cell management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive balancing is used to balance voltage and capacity of energy cells, then the system is simple and cost-effective, but energy is wasted and local temperature rise occurs
Solution Approach 1:
The patent implements a dynamic switching mechanism that alternates between passive balancing mode (using resistors for simple cells) and active balancing mode (using capacitors for efficient energy transfer). The system dynamically selects the appropriate balancing strategy based on cell characteristics and state, resolving the contradiction between circuit simplicity and energy efficiency.
Solution Approach 2:
The patent changes the balancing parameters by switching between different resistance values and capacitance values based on the specific cell state. By adjusting these parameters dynamically, the system optimizes the balance between energy loss and balancing effectiveness for each cell configuration.
2Loss of energy
If active balancing is used to balance voltage and capacity of energy cells, then energy loss is reduced, but the system becomes complex and expensive
Solution Approach 1:
The patent segments the balancing circuit into multiple independent modules, each handling specific cell groups. This segmentation allows the complex active balancing functionality to be distributed and managed in smaller units, reducing overall system complexity while maintaining energy efficiency.
Solution Approach 2:
The patent designs universal balancing circuits that can operate in multiple modes (passive and active) depending on the cell configuration. The same circuit architecture serves both simple resistance-based balancing and complex capacitor-based energy transfer, eliminating the need for separate circuits for each mode.
3Measurement precision
If capacity test is used to estimate state-of-health of storage cells, then the estimation is accurate, but the testing time is long
Solution Approach 1:
The patent performs preliminary measurements of voltage, current, and temperature during normal operation before the actual capacity test. These preliminary data are used to predict cell state and adjust the testing parameters, allowing for shorter test durations while maintaining accuracy through pre-gathered information.
Solution Approach 2:
The patent implements continuous feedback monitoring during the capacity test, adjusting the test parameters in real-time based on cell response. This feedback mechanism allows the system to terminate tests early when sufficient accuracy is achieved, significantly reducing testing time while maintaining measurement precision.
4Measurement precision
If high order equivalent circuit model is used to increase accuracy of dynamic model, then the model accuracy is improved, but the system becomes too complex for practical use
Solution Approach 1:
The patent applies partial modeling by using simplified equivalent circuit models for cells that do not require high precision, and reserves complex high-order models only for critical cells or specific operating conditions. This selective application of model complexity maintains overall system accuracy while avoiding unnecessary complexity throughout the entire system.
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 reduces energy and heat loss, simplifies the balancing circuit, and allows for quick and accurate SoH estimation, providing a compact and low-powered cooling system, while integrating with various energy storage technologies and applications.
Implementation Method 1
Passive balancing can be used to balance the voltage and capacity of the energy cells of rechargeable energy storage systems by using multiple resistors to discharge the excess amount of energy in the higher energy cells
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A modular management system is described for balancing, testing and protecting rechargeable energy storage cells connected in series. Different energy storage cell technologies can be connected in the same battery pack and they can be completely balanced by using one or both of two balancing modes. In addition, the modular management system comprises of bidirectional and unidirectional switches optionally connected to a single ohmic device such as a resistor for i.e., passive/active balancing, and testing mode for SoH/SoC estimation, preferably without using any extra or external components (i.e., capacitor or inductor or DC/DC converter or power supply).