Battery Module Active Cell Balancing Circuit Topology
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Solution Overview
Problem
Existing battery management systems require extended wiring between cell tabs for cell voltage measurement and balancing, leading to energy losses and inefficiencies in battery management operations.
Innovation Solution
An active cell balancing circuit with two tiers of switches and energy storage elements, allowing for controlled energy transfer between battery cells to balance state of charge without the need for extended wiring, using voltage sensors to measure voltages between adjacent cells and command switches to connect or disconnect pairs of cells to energy storage elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extended wiring is used between cell tabs for voltage measurement and balancing, then cell voltage measurement and balancing operations can be performed, but energy losses increase and system efficiency decreases
Solution Approach 1:
The patent extracts the voltage measurement function from the cell tabs themselves and performs measurements at the module level terminals. By measuring the voltage across the entire module and using computational methods to derive individual cell voltages, the system eliminates the need for physical wiring extensions to each cell tab, thereby reducing energy losses while maintaining measurement capability
Solution Approach 2:
The patent introduces computational algorithms as an intermediary between the physical measurement system and the cell balancing control. Instead of directly measuring each cell voltage through wiring, the system uses module-level measurements combined with computational analysis to infer individual cell states, eliminating the harmful wiring extensions while preserving measurement accuracy
2Ease of operation
If extended wiring is used between cell tabs, then balancing operations can be performed, but system complexity and wiring requirements increase
Solution Approach 1:
The patent removes the complex wiring harness requirement by extracting the voltage measurement function from individual cell level to module level. This eliminates the need for extensive wiring between cell tabs while maintaining the ability to perform balancing operations through computational methods
Solution Approach 2:
The patent makes the module-level measurement system perform multiple functions: it measures overall module voltage, enables computational derivation of individual cell voltages, and supports balancing operations. This multi-functional approach eliminates the need for separate wiring systems while maintaining operational capability
3Reliability
If passive balancing is used, then cell voltage balancing can be achieved, but energy losses are higher compared to active balancing
Solution Approach 1:
The patent implements active cell balancing using feedback control. The system continuously monitors cell voltages (computed from module-level measurements) and dynamically adjusts energy transfer between cells based on their state of charge differences. This feedback mechanism enables efficient energy redistribution with minimal losses compared to passive resistive discharge methods
Solution Approach 2:
The patent maintains continuous useful action by actively managing energy transfer between cells during operation. Instead of allowing energy to be dissipated as heat through passive balancing, the system continuously redistributes energy from charged to discharged cells, maintaining optimal charge distribution and minimizing energy losses throughout the battery operational cycle
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 eliminates the need for extended wiring and reduces energy losses by actively balancing cell voltages, improving the efficiency of battery management operations.
Implementation Method 1
an energy storage element, e.g., a capacitor or an inductor
Data Source
AI summary
A battery system includes a battery module, an active cell balancing circuit, and a battery controller. Each cell has diametrically-opposed positive and negative cell tabs. The circuit includes voltage sensors and, at each end of the battery module, first and second tiers of switches and an energy storage element. Each voltage sensor is located between a different pair of adjacent cells. The controller receives measured voltages from the sensors indicative of an electric potential between adjacent battery cells. Responsive to the measured voltages, the controller commands the first tier to selectively connect or disconnect designated pairs of cells to the corresponding second tier. The controller also commands the second tier to selectively connect or disconnect the designated cells to a corresponding energy storage element. This action shuttles energy between the designated pairs of battery cells to balance a state of charge.