Electrochemical Cell Assembly Staggered Switching Voltage Control
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Solution Overview
Problem
Existing methods for connecting electrochemical cells in series or parallel circuits result in fluctuating output voltage, necessitating large and costly choke coils for smoothing, as all cells are simultaneously connected or disconnected, leading to inefficient energy management in battery modules, particularly in electric vehicles.
Innovation Solution
A method that involves defining cell-specific switching commands and clock shift signals to delay the connection and disconnection times of individual cells within a cell assembly, preventing simultaneous operation and allowing for decentralized control of energy output, thereby reducing voltage excursions and the need for large choke coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If all cells are simultaneously connected or disconnected using a common clock signal, then the control system is simple and synchronized, but the output voltage fluctuates significantly between maximum value and 0, requiring large and costly choke coils for smoothing
Solution Approach 1:
The patent segments the cell assembly into multiple independently controllable cell groups, each with its own clock signal generator. This allows each group to be controlled separately rather than simultaneously, reducing the overall voltage fluctuation while maintaining decentralized control architecture.
Solution Approach 2:
The patent uses periodic clock signals with different phases for different cell groups. By staggering the switching timing of individual cells using phase-shifted clock signals, the voltage fluctuations are distributed over time rather than occurring simultaneously, reducing the peak-to-peak voltage variation.
2Adaptability or versatility
If cells are connected and disconnected simultaneously, then the battery voltage can be varied between maximum and 0 for PWM control, but this results in large voltage excursions that require expensive smoothing components
Solution Approach 1:
The cell assembly is divided into multiple cell groups that can be independently controlled. Each group contributes to the total voltage in a staggered manner, allowing the overall battery voltage to be regulated while avoiding simultaneous switching of all cells, thus reducing voltage excursions.
Solution Approach 2:
The patent changes the timing parameter of cell switching by introducing phase shifts between different cell groups. This parameter modification allows the system to maintain voltage control capability while reducing the amplitude of voltage fluctuations through temporal distribution of switching events.
3Ease of operation
If a centralized control system is used to manage all cells, then coordination is simplified, but the system requires large choke coils and cannot efficiently manage individual cell states
Solution Approach 1:
The control system is segmented into decentralized cell group controllers, each managing its own cells independently. This segmentation enables localized energy management decisions based on individual cell states while maintaining coordinated operation through standardized communication interfaces.
Solution Approach 2:
Each cell group controller autonomously manages its own cells based on local state information, making self-service decisions about switching and energy management. This eliminates the need for centralized coordination overhead and allows each group to optimize its energy usage independently.
Data Source
AI summary
A method includes activating electrochemical cells of a cell assembly to output electrical energy in accordance with a superordinate clock signal in order to have an activation and/or switch-off time points of the respective cells on the basis of the superordinate clock signal not all occur at the same time. To reduce the complexity of smoothing the total battery voltage, the switching time points according to the disclosure are shifted on the basis of the superordinate clock signal for the first cell in accordance with a first switching specification by a cell-specific first clock shift signal.