Hybrid Cell Balancing Circuit With Shared Switches and Capacitors
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Solution Overview
Problem
Existing battery balancing systems face inefficiencies due to high component count, complex control algorithms, and quiescent power loss, especially in hierarchical and modular structures, which affect the reliability and efficiency of serially connected batteries.
Innovation Solution
A hybrid-hierarchical balancing system that uses a single set of primary switches for both series and parallel balancing, employing local capacitors and a global capacitor to achieve voltage balancing without continuous current flow, thereby reducing component count and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hierarchical balancing structure with multiple separate converters is used, then balancing convergence speed is improved, but component count and system complexity increase
Solution Approach 1:
The patent combines series and parallel balancing functions into a single integrated converter per module, eliminating the need for separate converters. Each module contains one converter that can perform both series energy transfer and parallel energy buffering, reducing component count while maintaining fast convergence through the hybrid approach
Solution Approach 2:
The converter in each module is designed with multi-functionality to perform both series balancing (energy transfer between adjacent cells) and parallel balancing (energy buffering via capacitor). This universal design allows a single component to execute multiple balancing operations, reducing the total number of converters needed in the system
2Speed
If hierarchical balancing structure with multiple separate converters is used, then balancing convergence speed is improved, but system cost increases
Solution Approach 1:
By merging series and parallel balancing functions into a single converter per module, the patent reduces the total component count, which directly lowers manufacturing costs while preserving the fast convergence benefits of hierarchical structures
3Reliability
If continuous current flow is maintained in balancing system, then voltage balancing is achieved, but quiescent power loss increases
Solution Approach 1:
The patent employs periodic switching of transistors to control current flow in the balancing circuit. The switches operate in discrete on/off cycles, allowing energy transfer only when needed for voltage equalization. This periodic action eliminates continuous current flow and associated quiescent power losses while maintaining effective voltage balancing through controlled energy redistribution
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
The system achieves efficient voltage balancing with minimal quiescent power loss and reduced component count, enabling faster convergence and improved reliability in balancing serially connected batteries.
Implementation Method 1
a capacitor and inductor at said primary-side section of the module, that are configured to form a series resonant-type circuit
Data Source
Figure 1(a)
Figure 1(b)
Figure 1(c)
AI summary
The invention relates to hierarchical-hybrid system for balancing a series of cells, said cells are divided into m modules, each module having k cells, which comprises: (A) one or two central cells in each module and additional neighboring cells, each neighboring cell being adjacent to one of said central cells; (B) two local capacitors within a local section of each module, each of said local capacitors being periodically, repeatedly, and alternately connected (a) in parallel to one of said neighboring cells, or (b) in parallel to a respective central cell; (C) one global capacitor at a global section of each module which is common to all said modules, said global capacitor receiving respective charging signals either directly or through an isolation element, separately or simultaneously from several central cells of different of said modules, thereby to charge said global capacitor to a voltage level which is identical or proportional to the average voltage level of said central cells of all said different modules;(D) a plurality of controlled switches for carrying out said alternate connections of said local capacitors, and for forming said charging signals that are provided to said global capacitor; and (E) a controller for controlling the opening and closure of said controlled switches; wherein some of said controlled switches that are used to alternately connect said local capacitors to the respective cells at each module are also commonly used at said module to simultaneously produce said charging signals for charging the global capacitor; and wherein a connecting circuitry which comprises one or more reactive components and at least a portion of said controlled switches is used to connect said local section of each module to said global section.