Frequently Asked Questions
How is the Vanadium Redox Flow Battery system configured?
The basic components include a cell stack (layered liquid redox cells), an electrolyte, tanks to store the electrolyte, and pumps and piping for circulating the electrolyte. The system also consists of a power conversion system and a battery management system (BMS) for connection and control with the grid.
What are the advantages over LiB (Lithium-ion Batteries)?
The advantages of Vanadium Redox Flow Battery compared to LiB include:
1) They do not catch fire.
2) They have a long cycle life.
3) They are capable of long-duration operation.
How does the system respond to extreme environmental temperatures (high and low)?
In low-temperature environments, the pump speed is increased to maintain the electrolyte temperature. For even lower temperatures, heaters are used. In high-temperature environments, cooling is performed using heat exchangers.
What is the (design) lifespan of the battery system?
The lifespan is over 20 years. During this period, there is no need for cell stack replacement or electrolyte replenishment. However, regular maintenance through annual inspections is necessary. Without maintenance, there may be risks of capacity degradation or failure.
What is the response speed of the Vanadium Redox Flow Battery system?
The standard response speed is 0.1 seconds. However, the battery reactions occur much faster than this. The limiting factor is the response speed of the power conversion system (PCS). Frequency control has been demonstrated with both grid-side batteries and NEDO projects in North America.
Should we use the PCS provided by Sumitomo Electric? What specifications should it meet?
It is not necessary for the PCS to be provided by Sumitomo Electric. It should meet specifications such as overcurrent protection during initial charging (charging from 0V), communication protocol (Modbus TCP), and compatibility with the specified DC voltage range.
Can we use a PCS designed for solar power?
No, a PCS designed for solar power is not suitable as its application differs. Solar power systems operate in a unidirectional manner (using generated electricity), while batteries require bidirectional flow (charging and discharging), resulting in different specifications.
What communication environment and software are required for remote operation?
The communication environment uses Ethernet, and the protocol is Modbus TCP. For simple operations, free software can be sufficient, but complex operating modes will require additional software development.
Is a secondary containment system necessary?
The tank container has a double-tank structure (polyethylene and stainless steel). If the internal polyethylene is damaged, the stainless steel (SUS) tank can still store the liquid, preventing any leakage outside the facility. The system has a protective sequence that detects leaks when the internal polyethylene is damaged and will trigger an alarm and shut down the facility. The necessity of a secondary containment system is determined by the customer.
