Battery Cell Voltage Balancing Across Isolated AFE Stacks
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Solution Overview
Problem
In battery packs with multiple connected cells, voltage differences arise due to inconsistent power consumption of isolated power supplies, leading to unfavorable conditions for recycling and performance.
Innovation Solution
A voltage balancing system with a high-side and low-side analog front end, a microcontroller, and a communication isolating module, utilizing balancing modules and switch transistors to equalize voltages across sets of battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If two independent AFEs are used to manage multiple battery cells, then the battery pack can achieve high voltage and manage more cells, but the voltage difference between battery cell sets gradually increases due to inconsistent power consumption of isolated power supplies
Solution Approach 1:
The patent merges the power supply sources by connecting the positive ends of both isolated power supplies to a common positive busbar and negative ends to a common negative busbar, allowing the two AFEs to share a unified power reference. This eliminates the voltage drift caused by independent power supplies and maintains voltage consistency across all battery cells.
2Reliability
If isolated power supplies are used for communication isolation between AFEs and MCU, then communication safety is improved, but power consumption inconsistency causes voltage drift
Solution Approach 1:
The patent combines the power supply architecture by sharing the isolated power supply between the high-side AFE and low-side AFE, rather than using separate isolated power supplies for each. This unified approach ensures consistent power consumption and eliminates voltage drift while maintaining communication isolation safety through the isolating module.
3Measurement precision
If multiple independent AFEs are employed, then monitoring capability is enhanced, but system complexity increases due to multiple isolated power supplies
Solution Approach 1:
The patent reduces system complexity by merging the isolated power supply architecture - instead of requiring separate isolated power supplies for each AFE-MCU communication channel, a single isolated power supply serves both high-side and low-side AFEs. This simplifies the power distribution network while maintaining enhanced monitoring capabilities.
Data Source
AI summary
The invention provides a voltage balancing system for balancing controlling of voltage of battery cells including a first set of battery cells and a second set of battery cells connected in series. The system includes a high-side analog front end (AFE) connected to the first set of battery cells, a low-side analog front end (AFE) connected to the second set of battery cells, a microcontroller communicating with the high-side AFE and the low-side AFE, and a communication isolating module interconnecting between the high-side AFE and the microcontroller. The system further includes a balancing module arranged at a back end of the low-side AFE or the high-side AFE to equalize voltages output by the low-side AFE and the high-side AFE. Compared with the prior arts, the system employs a balancing module to balance the voltages of the two sets of battery cells, which can shorten the voltage difference therebetween.