Inter-module Voltage Balance Circuit for Series Storage Modules
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Solution Overview
Problem
Existing power storage systems with series-connected storage cells face significant challenges in compensating for voltage variations between modules during prolonged charging, particularly in modularized systems where maintenance is module-by-module, and existing solutions are not cost-effective or easily adjustable.
Innovation Solution
An inter-module voltage balance correcting circuit using a resistance voltage dividing circuit and complementary transistors to equalize voltage between modules, with additional features like bypass discharge resistive elements and overdischarge protection circuits, allowing for adjustable compensation of voltage variations between modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a balance correcting circuit compensates for voltage variation between cells, then voltage distribution is improved, but the circuit complexity and cost increase significantly
Solution Approach 1:
The patent segments the voltage balance correction function by introducing intermediate connection points between series-connected storage modules. Each module group is independently managed with its own balance correcting circuit, allowing localized voltage correction without requiring a complex system-wide circuit. This segmentation reduces overall circuit complexity while maintaining effective voltage distribution control.
Solution Approach 2:
The patent introduces intermediate connection points as intermediary elements between storage modules. These intermediaries enable voltage measurement and correction at module boundaries, simplifying the circuit architecture by avoiding the need for direct cell-level monitoring across all series-connected cells. The intermediary points serve as accessible nodes for voltage balance correction.
2Ease of repair
If storage cells are modularized into modules for easier maintenance, then ease of repair is improved, but voltage variation between modules becomes more significant
Solution Approach 1:
The patent applies segmentation by creating modular storage units with intermediate connection points between them. Each module can be independently maintained while the intermediate connection points enable voltage monitoring and correction at module boundaries. This maintains the maintenance advantage of modularization while addressing the voltage balance issue through localized correction circuits at each intermediate point.
Solution Approach 2:
The patent uses balance correcting circuits connected to intermediate points to maintain equipotential conditions between adjacent modules. By actively correcting voltage differences at the intermediate connection points, the system ensures that all modules operate at balanced voltage levels, preventing the accumulation of voltage variations that would otherwise occur in modularized systems.
3Power
If the number of series-connected modules is increased to achieve higher voltage, then power output is improved, but voltage variation between modules increases
Solution Approach 1:
The patent segments the high-voltage system into multiple modular units with intermediate connection points between them. This segmentation allows the system to achieve high voltage output through series connection of modules while providing distributed voltage correction capability at each intermediate point, preventing voltage variation from accumulating across the entire high-voltage string.
Solution Approach 2:
The patent implements feedback control through balance correcting circuits that continuously monitor voltage at intermediate connection points and actively correct voltage imbalances. This feedback mechanism ensures that even as the number of series-connected modules increases to achieve higher voltage, the system maintains voltage balance across all modules through real-time correction.
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 solution effectively compensates for voltage variations between modules in power storage systems, ensuring stable operation during prolonged charging durations at a low cost and with ease of adjustment, suitable for systems like instantaneous voltage drop compensation apparatuses for railroads.
Implementation Method 1
a resistance voltage dividing circuit that equally divides a series voltage across a first storage module and a second storage module connected in series
Implementation Method 2
a pair of transistors that are turned ON/OFF in a complementary manner based on a voltage that appears between an intermediate connecting point between the first and second storage modules and a voltage dividing point of the resistance voltage dividing circuit
Data Source
AI summary
Provided is an inter-module voltage balance correcting circuit of a power storage system including a plurality of storage modules connected in series, each of the storage modules including a plurality of storage cells connected in series. The inter-module voltage balance correcting circuit includes a resistance voltage dividing circuit (R1-R2) that equally divides a series voltage across a first storage module and a second storage module connected in series; and a pair of transistors that are turned ON/OFF complementarily based on a voltage (Vp1-Vp2) appearing between an intermediate connecting point (p2) between the storage modules M1, M2 in series and a voltage dividing point p1 of the resistance voltage dividing circuit, and a bypass discharge resistive element is selectively connected to modules by turning ON/OFF the complementary transistors.