Cell Balancing Circuit Using Isolation Power Supply
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Solution Overview
Problem
Capacity variations among battery cells in a pack lead to differences in charging and discharging voltages, resulting in overcharging or overdischarging, which reduces battery capacity and shortens lifespan due to inefficient passive cell balancing methods that consume power as heat.
Innovation Solution
A cell balancing circuit with an isolation power supply that receives the total voltage of series-connected battery cells, applying charging voltage to cells with lower voltages through independent switches controlled by a controller, allowing for equalization without heat consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If passive cell balancing is used to equalize battery cell voltages, then voltage differences between cells are minimized, but power is consumed as heat and battery capacity is not fully utilized
Solution Approach 1:
Instead of passively discharging high-voltage cells through resistors to equalize voltages, the invention inverts the approach by actively charging low-voltage cells using a DC-DC converter. This transfers energy from high-voltage cells to low-voltage cells, achieving voltage equalization without energy loss as heat.
Solution Approach 2:
The invention introduces a DC-DC converter as an intermediary device between battery cells. This converter acts as a mediator that receives energy from high-voltage cells and delivers it to low-voltage cells, enabling efficient energy transfer and voltage equalization without direct resistive discharge.
2Stability of the object's composition
If passive cell balancing discharges high-voltage cells through resistors, then voltage differences are reduced, but 100% battery capacity cannot be used
Solution Approach 1:
The invention inverts the conventional balancing approach by charging low-voltage cells instead of discharging high-voltage cells. This allows the battery system to utilize 100% of its capacity while still achieving voltage equalization through the DC-DC converter that transfers energy selectively to cells needing charge.
Solution Approach 2:
The battery system performs self-balancing by using its own internal energy reserves. High-voltage cells automatically supply energy through the DC-DC converter to low-voltage cells, enabling the system to maintain voltage equality and full capacity utilization without external intervention or energy loss.
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
Enables the use of 100% battery capacity by applying charging voltage only to cells needing it, reducing power consumption and extending battery life by minimizing heat loss during balancing.
Implementation Method 1
an isolation power supply for receiving the total voltage of a plurality of battery cells connected in series
Data Source
Figure 1~2
Figure 3
AI summary
A battery cell balancing system (100) is disclosed. In one embodiment, the system includes a plurality of battery cells (B1, B2, B3) arranged in series and a power supply (110) configured to receive the cumulative voltage of the battery cells (B1, B2, B3) and output a first charging voltage to one of the battery cells that has a voltage less than a reference voltage. According to one embodiment, it is possible to implement a cell balancing operation using the cumulative voltage of the battery cells.