Energy Storage Assembly with Individual Cell Converters
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Solution Overview
Problem
High-performance energy storage systems, such as those in electric vehicles, face premature failure due to variations in cell properties caused by production tolerances and environmental factors, leading to uneven charging and discharging characteristics and premature cell degradation.
Innovation Solution
An energy storage arrangement where cells are connected to a power output and control unit via floating, controlled converters, allowing for individual operation based on each cell's performance characteristics, enabling the use of cells with different properties and facilitating their replacement without disconnecting the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cells with different electrical properties are used to meet power and capacity requirements, then the energy storage arrangement can achieve required performance, but individual cells are subject to greater stress and are destroyed prematurely
Solution Approach 1:
The patent divides the series connection of cells into multiple parallel strings, where each string contains a subset of cells. This segmentation allows cells with different electrical properties to be grouped within the same string, enabling them to operate together without causing premature failure of the entire accumulator. The parallel string structure ensures that the weakest cell in each string determines the base current, while stronger cells can contribute additional current through their own converters.
Solution Approach 2:
The patent implements individual controlled converters for each cell or cell group, allowing each cell to operate with its own optimized current characteristics. This local quality approach enables cells with different electrical properties to be treated individually, with each cell's converter adjusting its output to match the cell's specific capabilities, thereby preventing stress on weaker cells while maximizing the contribution of stronger cells.
2Reliability
If conventional accumulators use cells with uniform properties, then cell lifespan is extended, but replacement of defective cells is difficult and the system cannot accommodate cells with different electrical properties
Solution Approach 1:
The patent creates a universal system architecture where each cell is equipped with its own controlled converter, making each cell independently replaceable without affecting the overall system operation. The parallel string structure with individual converters allows cells of different types and properties to be mixed within strings, providing versatility in cell selection and replacement while maintaining system reliability through the modular design.
3Productivity
If individual cell monitoring and control is implemented, then cell performance can be optimized, but the device complexity increases
Solution Approach 1:
The patent combines the controlled converter and control unit into an integrated module that can be assigned to each cell or group of cells. This merging approach reduces the overall system complexity by consolidating functions that would otherwise be separate components. The integrated module design allows for standardized production and easier installation while maintaining individual cell control capabilities.
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 solution allows for the flexible combination of cells with different technologies, extends the life of energy storage systems, and enables early detection of cell defects, preventing thermal runaway and optimizing charging and discharging processes for efficient energy use.
Implementation Method 1
at least some of the cells connected in series are connected to the power output and the control unit via floating, controlled converter and control units connected in parallel in such a way that by means of targeted current draws through the converter and control units of each of the cells are operated during the charging, discharging and recharging processes
Data Source
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AI summary
The invention relates to an energy storage assembly, comprising a plurality of cells connected in series, wherein the series connection of cells is connected to a power output of the energy storage assembly and a control unit, wherein at least a part of the cells (Z1, Z2,...Zn) connected in series is connected to the power output (5, 6) and the control unit (BMS-C) by way of potential-free controlled converter and control units (IRl,IR2,...IRn) connected in parallel, such that during the charging, discharging and recharging processes each of the cells (Z1, Z2,...Zn) is operated according to the individual performance characteristics of said cell (Z1, Z2,...Zn) by means of selective current drains by the converter and control units (IRl,- IR2-,...IRn) and a total current flowing at the power output of the energy storage assembly (5, 6) is formed by a base current flowing through the series connection of the cells (Z1, 7.2,...Zn) and by additional currents, which are drained from the individual cells (Z1, Z2,...Zn) depending on the capacity of the cells. The invention allows for the interconnection of different cell types to form an energy storage assembly and for uniform charging or discharging thereof, thus facilitating optimal use of the energy stored and extending the total usage period.