Intelligent CIO Middle East Issue 56 | Page 52

FEATURE: LITHIUM BATTERY ERA Data centre According to a global survey conducted by Uptime, 10% of data centres use lithium batteries as backup power. For data centre operators, the optimal space utilisation and minimum operating costs (especially power costs of UPS cooling and battery maintenance and replacement costs) are what they are most concerned about. Lithium batteries can help them meet all these requirements. stability as well as a low rate and amount of heat yield 3. LFP batteries do not release oxygen in case of overcharge and over discharge Test conclusion: LFP batteries are more reliable than NCM batteries. Common test method: • Puncture the cell with a needle to check its stability in the case of an internal short circuit • Secure the fully charged battery ACCORDING TO A GLOBAL SURVEY CONDUCTED BY UPTIME, 10% OF DATA CENTRES USE LITHIUM BATTERIES AS BACKUP POWER. Telecom base station During the process of 5G evolution, the total power consumption of a site rockets. Traditional lead-acid batteries cannot support smooth capacity expansion to adapt to 5G evolution because of their large size and weight, short service life and inferior performance. Small, lightweight lithium batteries feature longer service life and better performance. They can enable sites to evolve smoothly to 5G and improve site values. Therefore, lithium batteries have become the first choice for 5G sites. Currently, more than 200 telecom operators use lithium batteries as their energy store. In data centres and telecom base stations, LFP and lithium nickel manganese cobalt oxide (NMC) cells are most commonly used. LFP is, at present, the safest cathode material of a lithium battery for it contains no heavy metal that is harmful to humans. Compared with NMC batteries, LFP batteries are more reliable, which better meets high reliability requirements of data centres and telecom base stations. Why are LFP batteries needed? 1. Stable Structure 2. LFP batteries feature high thermal • Use an 8mm diameter high-temperatureresistant steel needle to puncture through the geometrical centre of the cell in the direction vertical to the cell polarity plate at a speed of 25 mm/s, keep the needle in the cell and observe for one hour Test conclusion: • After an LFP battery is punctured with a needle (internal short circuit), the heat of reaction inside the cell is minimal. The highest surface temperature of the cell is only 80ºC, the cell does not catch fire or leak electrolytes and its shell is intact. • After an NCM battery is punctured with a needle (internal short circuit), the cell reacts violently internally and generates a large amount of heat and oxygen in a short time. The battery burns within one second, thermal runaway occurs within four seconds, the highest surface temperature reaches 458ºC, and the shell melts. Though its technology has been improved a lot, the lithium battery still has many problems in practical application. • When multiple battery cabinets are connected in parallel, current imbalance occurs due to inconsistent cell resistance and capacity and power distribution differences, especially for short-time discharge of a large current. As a result, overcurrent protection is triggered in each battery cabinet. • Partial failure is unavoidable in a lithium battery system. New and old battery cabinets may be connected in parallel. If resistance and capacity are inconsistent in this case, serious bias current can be caused and a battery cabinet can even be disconnected in case of overcurrent. • Inconsistency of cell resistance and capacity in a battery can cause cell charge overvoltage, so that the entire battery system cannot be fully charged. • If a battery module in a battery string is faulty, the entire battery string cannot work properly. • If fire occurs in a lithium battery cabinet after lithium batteries are deployed in a modular data centre, it is hard to control the fire inside the cabinet and prevent it from spreading to ICT equipment nearby. • Lithium batteries at base stations are prone to be stolen. In view of this, Huawei launched the new-generation data centre lithium battery solution SmartLi. Characterised with high reliability, efficiency and flexible expansion, SmartLi is aimed to help customers reduce investment, simplify O&M and build a stable and efficient data centre power supply system. 1. Reliable • Long Lifespan, cycle life can be up to 5,000 times. • Highly stable LFP cell, no fire when thermal runaway. • Intelligent voltage balance control, single module failure system can work normally. • Three-layer BMS system ensures the reliability of lithium batteries layer by layer. 2. Efficient • High power density, save 70% footprint compared with lead-acid battery. • Intelligent battery management system, save 80% of daily O&M costs. 3. Simple • Modular swappable design, easy maintenance. • Active current balance technology, new and old battery strings can be connected in parallel, simple capacity expansion. 52 INTELLIGENTCIO www.intelligentcio.com