Controllable Energy Store Cell Transfer for Reliability
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Solution Overview
Problem
Conventional energy storage systems in electric vehicles and wind turbines face reliability issues due to the series connection of battery cells, where a single cell failure can lead to system failure, and existing solutions for charge equalization are not sufficient to ensure high reliability and efficient energy transfer.
Innovation Solution
A method for reloading energy between energy storage cells in a controllable energy storage device with parallel energy supply branches, using controllable coupling units to switch energy storage cells into or isolate them from the energy supply branches, allowing for balanced charge distribution and simultaneous charging or use as an energy source, without additional hardware or space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If battery cells are connected in series to achieve high overall voltage, then voltage requirement is met, but system reliability deteriorates because a single cell failure causes complete system failure
Solution Approach 1:
The battery system is divided into multiple independent parallel strands, each consisting of series-connected battery modules. This segmentation allows individual strands to be isolated in case of failure, preventing single-point failures from causing complete system shutdown while maintaining voltage requirements through series connections within each strand.
Solution Approach 2:
The system incorporates coupling units with switching elements that can preemptively isolate specific battery cells or modules before failures propagate. This protective mechanism cushions the system against reliability deterioration by containing potential failure points within individual strands or modules.
2Power
If additional battery cells are connected in parallel to increase maximum current, then current capacity is improved, but device complexity increases
Solution Approach 1:
The parallel connection architecture is organized into distinct strands with clear modular structures. Each strand contains series-connected modules that can be independently controlled, making the complexity manageable through systematic segmentation rather than random parallel connections.
Solution Approach 2:
The coupling units serve multiple functions: they control current flow paths, isolate failed cells, enable charge equalization between modules, and support both series and parallel connection configurations. This multi-functionality reduces the need for additional dedicated components, thereby limiting complexity growth.
3Reliability
If charge equalization is implemented between battery cells, then reliability is improved, but device complexity and hardware requirements increase
Solution Approach 1:
The system uses its own operational phases (charging and free-wheeling phases) to perform charge equalization internally. During the free-wheeling phase, energy is naturally redistributed from cells with higher charge to those with lower charge through the existing circuit topology, eliminating the need for separate equalization hardware.
Solution Approach 2:
The charge equalization function is merged with the existing power conversion and control operations. The same coupling units and switching elements used for primary power management also facilitate charge redistribution, combining multiple functions into a unified system architecture.
4Productivity
If coupling units control energy storage cells to be switched into or isolated from energy supply branches, then energy transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The coupling units are designed as multi-functional components that simultaneously perform switching, isolation, and charge equalization operations. This universal design consolidates control functions that would otherwise require separate dedicated components, improving energy transfer efficiency without proportionally increasing overall system complexity.
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 method ensures reliable energy transfer and balanced charge distribution across energy storage modules, preventing system failures and enabling efficient energy use in electric machines, while avoiding undesirable torques during the charging process.
Implementation Method 1
electrical energy is stored in the stator windings of the electrical machine during a charging phase
Implementation Method 2
the inductance of the stator windings drives the current further and in this way charges the energy storage cells
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a method for transferring energy between at least two power cells (5) in a controllable energy store (2) used for controlling and supplying electric power to an n-phase electric machine (1). The energy store (2) has n power supply branches (3-1, 3-2, 3-3), each of which includes at least two serially connected energy storage modules (4). Each energy storage module comprises at least one electric power cell (5) having an associated controllable coupling unit (6) and is connected to one respective phase (U, V, W) of the electric machine (1). In a charging phase, all coupling units (6-11) of the energy storage modules (4-11) to be used as a source of energy are controlled in such a way that the associated power cells (5-11) are connected to the respective power supply branch (3-1). All coupling units (6-31 to 6-3m) located in a power supply branch (3-3) of power cells (5-3m) to be charged are controlled in such a way that the associated power cells (5-31 to 5-3m) are bridged. In a freewheeling phase following the charging phase, all coupling units (6-3m) associated with power cells (5-3m) to be charged are controlled in such a way that the associated power cells (5-3m) are connected to the respective power supply branch (3-3).