Inductor-Based Active Balancing for Series Battery Modules
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Solution Overview
Problem
Conventional passive voltage balancing systems in battery modules dissipate electrical energy using resistors, leading to significant energy loss and reduced operational life due to manufacturing and environmental variations in battery cell voltages.
Innovation Solution
An inductor-based active balancing system using an LC resonance circuit and multiple switches to transfer energy between power supplies connected in series, reversing current flow through the inductor to achieve efficient voltage balancing without energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional passive voltage balancing systems use resistors to dissipate electrical energy from battery cells with excessive output voltage, then voltage balancing is achieved, but significant energy is lost and operational life is shortened
Solution Approach 1:
Instead of dissipating excess energy through resistors, the patent inverts the approach by using an inductor to store excess energy from high-voltage battery cells and transferring it to low-voltage cells. The inductor-based active balancing system converts the harmful energy dissipation into useful energy transfer, thereby achieving voltage balancing while preserving and even utilizing the excess energy.
Solution Approach 2:
The patent transforms the harmful effect of excess energy (which would normally be wasted as heat through resistors) into a beneficial resource by storing it in the inductor and redistributing it to undercharged battery cells. This converts the energy loss problem into an energy optimization solution, improving overall system efficiency.
2Reliability
If resistors are used to dissipate electrical energy for voltage balancing, then voltage variations are compensated, but operational life of the battery is reduced
Solution Approach 1:
The patent inverts the conventional approach by not dissipating energy but rather storing and redistributing it. The inductor-based system reverses the energy flow direction, transferring energy from high-voltage to low-voltage cells, thereby achieving voltage compensation without the harmful thermal effects that reduce battery operational life.
Solution Approach 2:
By converting the energy dissipation process into energy storage and transfer, the system eliminates the thermal stress and energy waste that would otherwise shorten battery life. The inductor acts as an energy buffer that protects battery cells from the harmful effects of resistor-based dissipation.
3Loss of energy
If inductor-based active balancing is used to transfer energy between power supplies, then energy efficiency is improved, but system complexity increases due to LC resonance circuit and switches
Solution Approach 1:
The patent employs dynamic switching control of the LC resonance circuit to manage energy transfer between battery cells. The switches are controlled in a dynamic sequence to activate specific inductors and capacitors based on the real-time voltage states of different cells, enabling efficient energy redistribution while managing circuit complexity through controlled activation.
Solution Approach 2:
The LC resonance circuit acts as an intermediary mechanism between battery cells, facilitating energy transfer without direct cell-to-cell connection. The inductor and capacitor serve as mediating energy storage elements that enable controlled energy exchange, reducing the need for complex direct control circuits between each battery cell pair.
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 achieves higher efficiency, up to 85% or more, with reduced component costs and increased flexibility for various charging/discharging algorithms, extending battery life by minimizing energy dissipation.
Implementation Method 1
The inductor is configured to store energy to be transferred between two or more of the power supplies
Implementation Method 2
The additional switch is configured to selectively create a resonance between the inductor and the capacitor in order to reverse a direction of a current flow through the inductor
Data Source
AI summary
A system includes multiple power supplies connected in series and an active balancing circuit. The active balancing circuit includes an LC resonance circuit and multiple switches configured to selectively couple different ones of the power supplies to the LC resonance circuit. The LC resonance circuit includes an inductor, a capacitor, and an additional switch. The inductor is configured to store energy to be transferred between two or more of the power supplies. The additional switch is configured to selectively create a resonance between the inductor and the capacitor in order to reverse a direction of a current flow through the inductor. The active balancing circuit can transfer energy between individual power supplies or groups of power supplies.