Fly Capacitor Battery Balancing Circuit for Voltage Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In a battery pack with serially coupled battery units, voltage imbalances lead to shortened unit lifetimes and decreased capacity, necessitating a method to balance voltages for safe and stable operation.
Innovation Solution
A battery balancing method using a fly capacitor, where switching circuits charge or discharge the capacitor from one battery unit to another based on voltage values, ensuring equalization of voltages between units within a switching cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional battery balancing methods are used, then voltage balancing can be achieved, but the balancing efficiency is low and time-consuming
Solution Approach 1:
The patent implements periodic switching action by alternately connecting the fly capacitor to different battery units through switching circuits. The capacitor charges from one battery unit and discharges to another in periodic cycles, enabling efficient voltage balancing through repeated charge transfer operations rather than continuous direct connection methods.
Solution Approach 2:
The fly capacitor serves as an intermediary energy storage element between battery units. Instead of directly connecting battery units for balancing, the capacitor mediates the energy transfer by charging from higher voltage units and discharging to lower voltage units, enabling indirect but efficient voltage equalization across the battery pack.
2Reliability
If voltage balancing is not performed, then the circuit structure remains simple, but battery unit lifetime shortens and capacity decreases
Solution Approach 1:
The patent divides the battery pack into multiple independently controllable units, each with its own switching circuit connected to the fly capacitor. This segmentation allows individual voltage control and balancing for each battery unit, enabling precise voltage equalization while maintaining overall system reliability and extending battery lifetime.
3Loss of energy
If direct voltage equalization between battery units is implemented, then voltage balancing is achieved, but energy loss increases
Solution Approach 1:
The patent changes the operating parameters by using the fly capacitor to store and transfer energy in discrete charge/discharge cycles. The capacitor voltage builds up during charging from higher voltage battery units and releases energy during discharging to lower voltage units, optimizing the energy transfer parameters to minimize losses while maintaining high balancing efficiency.
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 achieves efficient voltage balancing between battery units, with an efficiency of above 95%, preventing voltage differences and ensuring equal voltages across units, thereby extending battery life and maintaining pack stability.
Implementation Method 1
charging the fly capacitor from the first battery unit or discharging the fly capacitor to the first battery unit
Data Source
AI summary
A battery balancing method and circuit for balancing the voltages between battery units with a fly capacitor. In a first time period of a switching cycle, the first battery unit is used to charge the fly capacitor or the first battery unit is used to discharge the fly capacitor, depending on which of the first battery unit and the fly capacitor having a larger voltage value; and in a second time period of the switching cycle, the second battery unit is used to charge the fly capacitor or the second battery unit is used to discharge the fly capacitor, depending on which of the second battery unit and the fly capacitor having a larger voltage value.