Overall core conclusion: The specialized pipe for High Efficiency Liquid Coolant Flow Battery Tubes is a high-quality insulation material, but the electrolyte circulating inside the pipeline has conductivity. Therefore, the pipe only serves as an isolation and protection function, and the high-voltage insulation guarantee of the entire system cannot rely solely on the pipeline body.
1、 Insulation characteristics of commonly used pipe materials
High end fluoroplastic material is a high-quality pipe material for flow batteries, with excellent insulation performance and strong medium stability. It can adapt to fluctuations in temperature and environmental humidity, and its insulation performance will hardly deteriorate during long-term use. At the same time, it is resistant to electrolyte corrosion and is commonly used in core pipelines of large energy storage power plants.
Conventional engineering plastic materials are the mainstream choice for pipes in the industry, naturally possessing good insulation properties and outstanding cost-effectiveness, which can meet the basic isolation needs of mainstream flow battery systems such as vanadium and iron chromium. Only under long-term high temperature and continuous immersion in acidic electrolyte conditions, the insulation performance will experience slight degradation, and sufficient safety margin should be reserved when selecting engineering.
The metal pipeline lined with fluoroplastic has a conductive outer layer of metal, and its overall insulation performance relies entirely on the support of the internal lining layer. The reliability of insulation depends entirely on the integrity of the lining layer. Once the lining layer is damaged, it will directly cause grounding and leakage problems. Ordinary exposed metal pipelines are strictly prohibited from being used in electrolyte circulation circuits, as they can directly cause faults such as leakage and electrochemical corrosion.
2、 Core characteristics of insulation under actual working conditions
The insulation logic of flow battery pipelines is completely different from that of ordinary insulated pipelines. The working medium inside the pipeline itself can conduct electricity, and the pipeline wall only serves as a physical isolation barrier, not the main insulation structure of the system.
On the premise that the pipe is intact, without cracking, leakage, or detachment, the pipe wall can effectively isolate the internal charged electrolyte, isolate the external metal bracket from the ground, and avoid the risk of leakage. The weak insulation points of the pipeline system are mostly concentrated in the flange, connection joint, and sealing accessory positions. After long-term operation, it is easy to accumulate salt and produce condensation and creepage phenomena. The vast majority of insulation failure problems occur at the joint parts rather than the pipe body.
3、 System insulation acceptance criteria
The insulation acceptance of the flow battery system requires testing the ground insulation performance under the true operating state where the pipeline is completely filled with electrolyte. The insulation effect tested under the empty tube state is not referential, the values are biased, and cannot reflect the insulation capacity of the actual working conditions. The industry compliance standard is that the insulation status of the entire system meets the standard and there is no leakage hazard. The insulation safety requirements for large capacity high-voltage systems will be more stringent.
4、 The main reason for the decrease in insulation performance of pipelines
Long term high temperature operation can cause aging of pipes, and continuous infiltration of electrolyte can cause swelling of pipes, gradually reducing their insulation performance; The accumulation of electrolyte salt spray on the outer surface of the pipeline and the condensation caused by humid environment can cause surface creepage and damage the overall insulation; Mechanical collisions and stress deformations caused by transportation, installation, and operational vibrations can result in subtle cracks that are not visible to the naked eye, leading to implicit insulation failure; Choosing ordinary pipes that are not resistant to electrolytes will quickly become brittle and completely lose their insulation ability after long-term immersion.
5、 Summary
Compliant non-metallic dedicated pipelines for flow batteries, with stable and reliable insulation performance. The key to insulation safety in the system is not the strength of the insulation of the pipe itself, but the ability of the pipe to resist corrosion and leakage, as well as the sealing reliability of the pipeline joints and sealing parts, which are affected by the characteristics of the internal conductive electrolyte medium. This prevents the leakage of conductive electrolyte from causing grounding leakage faults at the root.
