Floating Common Bus Voltage Equalization for Energy Storage
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Solution Overview
Problem
Existing energy storage apparatuses with voltage equalizing functions face safety concerns due to grounded common buses, which can lead to electric shock and leakage risks, and suffer from poor energy efficiency in voltage equalization processes.
Innovation Solution
An energy storage apparatus with a common bus that is electrically floating, utilizing switching transformers for bidirectional energy transfer between energy storage devices, allowing for safe and efficient voltage equalization across multiple modules and cells without connecting to both electrodes, thereby reducing the risk of electric shock and improving energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the common bus is grounded to provide a reference potential, then the voltage equalization function can be implemented, but the risk of electric shock and electric leakage increases
Solution Approach 1:
The patent introduces an isolation transformer as an intermediary component between the grounded reference potential and the common bus. The transformer's primary winding connects to the grounded reference, while the secondary winding provides electrical isolation to the common bus. This mediator allows magnetic coupling for voltage reference while preventing direct electrical connection, thus eliminating the shock hazard while maintaining the equalization function.
Solution Approach 2:
The patent replaces the direct electrical connection (conductive path) with a magnetic field-based energy transfer mechanism through the isolation transformer. Instead of using wires to connect the grounded reference to the common bus, the system uses electromagnetic induction via the transformer windings to establish the voltage reference relationship without physical electrical contact.
2Reliability
If the resistance discharge type balancer circuit is used to equalize voltages, then the voltage equalization function is achieved, but energy efficiency is poor and large amounts of heat are generated
Solution Approach 1:
The patent uses the common bus as an intermediary energy transfer medium. Instead of directly discharging high-voltage cells through resistors, the system transfers energy from high-voltage cells to the common bus, and then from the common bus to low-voltage cells. This two-stage transfer through the common bus intermediary reduces energy loss compared to direct resistance discharge.
Solution Approach 2:
The patent recovers energy that would otherwise be wasted. In the voltage equalization process, energy from high-voltage cells is transferred to the common bus and then recovered by low-voltage cells that need charging. This recovers what would have been lost heat in resistance discharge circuits, converting waste energy into useful energy for balancing.
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
The solution effectively equalizes voltages across energy storage devices, enhances safety by minimizing electric shock and leakage risks, and optimizes energy usage by allowing bidirectional energy transfer with reduced component count and adjustable energy transfer cycles.
Implementation Method 1
the energy transfer circuit includes one or more switching transformers each having a first winding connected to the energy storage device and a second winding connected to the common bus
Data Source
AI summary
A power storage device 20 comprises: a plurality of power storage elements C1-C6 that are connected in series; energy transfer circuits 40 provided respectively to the plurality of power storage elements C1-C6; a common bus 50 to which the energy transfer circuits 40 of the plurality of power storage elements C1-C6 are commonly connected; and a control device 70. Each energy transfer circuit 40 includes one or a plurality of switching transformers Tr, each switching transformer having a first winding 41A that is connected to the power storage elements C1-C6 and a secondary winding 41B that is connected to the common bus 50. The control device 70 uses the switching transformers Tr of the energy transfer circuits 40 to transfer energy between the power storage elements via the common bus 50, thereby equalizing the voltages of the power storage elements C1-C6. The common bus 50 is in an electrically floating state.