Inductor-Based Stack Balancing for Energy Storage
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Solution Overview
Problem
Existing methods for balancing energy in a battery or capacitor stack are inefficient, often requiring expensive transformers and multiple power conversion steps, leading to significant energy loss and complexity.
Innovation Solution
A DC/DC switching regulator topology using a single inductor and four switches per cell, controlled by a shared or distributed controller, allows for efficient energy transfer between cells without the need for transformers, enabling direct power conversion and simple control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transformers are used in fly-back configuration to move energy from a single battery or capacitor back into the stack, then energy transfer is achieved, but device complexity and cost increase due to large or expensive transformers
Solution Approach 1:
The patent extracts the transformer component from the energy transfer system and replaces it with a direct inductor-based switching circuit. By removing the transformer, the system eliminates the associated complexity and cost while maintaining energy transfer capability through the inductor L and switching elements Q1-Q4.
Solution Approach 2:
The patent substitutes the electromagnetic transformation mechanism (transformer) with a direct electrical switching mechanism using inductors and transistors. This replacement uses electronic switching control instead of magnetic coupling, reducing device complexity while achieving the same energy transfer function.
2Device complexity
If a buck converter is used to move energy from one cell to adjacent cells, then energy transfer is achieved, but productivity decreases due to multiple power conversion steps required for cells several cells away
Solution Approach 1:
The patent creates a universal energy transfer circuit that can move energy from any single cell to any other cell or subset of cells in the stack through the common inductor L. This multi-functional approach eliminates the need for multiple sequential conversion steps, as the circuit can directly transfer energy between any cell pairs, improving productivity while maintaining simple circuitry.
3Ease of operation
If passive balancing methods using FET and resistor are used to dissipate energy from a particular cell, then energy balancing is achieved, but loss of energy increases due to dissipation within the resistor
Solution Approach 1:
The patent converts the previously harmful energy dissipation into a beneficial energy transfer process. Instead of dissipating excess cell energy as heat in a resistor, the switching circuit captures this energy via the inductor and redirects it to other cells that need charging. This transforms waste energy into useful energy, maintaining balancing functionality while eliminating energy loss.
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 eliminates the need for transformers, achieves high power processing efficiency, and allows for bi-directional energy transfer with minimal energy loss, while maintaining simplicity and cost-effectiveness.
Implementation Method 1
An electronic switching system may control the delivery of energy into and out of the inductor
Data Source
AI summary
An energy storage stack balancing circuit may balance a set of serially connected energy storage devices. An electronic switching system may control the delivery of energy into and out of the inductor. A controller may control the electronic switching system so as to cause energy to be transferred: from one of the energy storage devices into the inductor and then out of the inductor and into a different one, a subset, or all of the energy storage devices; or from a subset of the energy storage devices into the inductor and then out of the inductor and into one, a different subset, or all of the energy storage devices; or from all of the energy storage devices into the inductor and then out of the inductor and into one or a subset the energy storage devices.