Battery Cell Charge Balancing via Selective Switching
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Solution Overview
Problem
Battery cells connected in parallel face challenges in state of charge adjustment due to compensating currents and internal resistances, leading to energy losses, premature aging, and uneven loading, making it difficult to achieve uniform charge states.
Innovation Solution
A method using semiconductor switches to selectively activate and deactivate battery cells, allowing for dynamic adjustment of their states of charge, enabling active balancing and optimizing energy distribution by determining and monitoring charge states and applying a predetermined selection rule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If battery cells are connected in parallel with switching technology to enable charge adjustment, then charge adjustment becomes possible, but device complexity increases significantly
Solution Approach 1:
The patent extracts the switching technology from the parallel connection configuration itself and places it only in the series connection paths. Each battery cell group has switching elements in its series connection path, allowing independent control of charge flow to and from each group without requiring complex switching at the parallel connection points. This reduces overall device complexity while maintaining charge adjustment capability.
Solution Approach 2:
The battery system is segmented into multiple battery cell groups connected in series, where each group can be independently controlled via switching elements. This segmentation allows the system to achieve charge adjustment by controlling individual series groups rather than managing complex parallel switches, thereby reducing device complexity while maintaining adaptability.
2Stability of the object's composition
If compensating currents are allowed to flow between battery cells with different no-load voltages, then charge equilibrium is approached, but energy losses increase due to internal resistances
Solution Approach 1:
The patent implements preliminary action by using control units to detect voltage differences between battery cell groups before compensating currents flow. The control units then activate switching elements to pre-adjust the charge distribution, enabling controlled charge transfer that achieves equilibrium while minimizing energy losses from uncontrolled compensating currents.
Solution Approach 2:
The system employs feedback mechanisms where control units continuously monitor the voltages of individual battery cell groups and adjust the switching elements accordingly. This feedback control enables the system to achieve charge equilibrium by actively managing charge flow based on real-time voltage measurements, thereby reducing energy losses compared to passive compensating current flow.
3Adaptability or versatility
If battery cells with different states of charge are operated in parallel, then operational flexibility is maintained, but uneven loading occurs leading to premature aging
Solution Approach 1:
The patent implements dynamic control by enabling the battery system to operate with different connection configurations. Battery cell groups can be dynamically switched between series and parallel connections based on their state of charge and operational requirements. This dynamic reconfiguration allows the system to maintain operational flexibility while preventing uneven loading by adjusting which cells are active in which configuration, thereby extending battery life.
4Ease of operation
If series connection paths include switching elements for charge adjustment, then state of charge control is achieved, but device complexity increases
Solution Approach 1:
The switching elements in the series connection paths serve multiple functions: they enable charge adjustment between battery cell groups, allow dynamic reconfiguration of series-parallel connections, and provide control over which battery groups are actively engaged. This multi-functionality reduces the need for separate control mechanisms, thereby achieving ease of operation while minimizing the increase in device 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 approach allows for precise control of battery cell states, reducing energy losses, extending battery life, and ensuring optimal operational readiness by minimizing power imbalances and aging, while enabling efficient energy use and balancing across cells.
Implementation Method 1
activation of those battery cells that are adjusted by means of a respective semiconductor switch of the battery cells and deactivation of the remaining battery cells by means of the semiconductor switch of the respective remaining battery cells
Implementation Method 2
A battery cell is a device that has two electrodes that interact electrochemically with each other. The interaction can occur with supplemental assisting action of an electrolyte.
Implementation Method 3
If, in the case of individual battery cells, even slight differences in voltage exist in relation to their respective individual no-load voltage, then, at the instant of interconnection to create a parallel circuit, a corresponding compensating current flows.
Implementation Method 4
The compensating current is limited via the particular internal resistances of the battery cells in question as well as by way of contact resistances between connection terminal contacts of the battery cells and an electrical connection for producing the parallel connection of the battery cells.
Data Source
AI summary
A method for the adjustment of states of charge of battery cells that are operated electrically in parallel connection, with the following steps: determination of the states of charge of the battery cells; selection of those battery cells whose states of charge are to be adjusted in accordance with a predeterminable selection rule; activation of those battery cells that are adjusted by means of a respective semiconductor switch of the battery cells, and deactivation of the remaining battery cells by means of the semiconductor switches of the respective remaining battery cells; carrying out the adjustment of the states of charge and monitoring of the states of charge; and termination of the adjustment of the states of charge when a predetermined state of charge has been attained by the activated battery cells.