How Data Center Operators Choose the Right Battery
lead-acid battery
Nowadays, lead-acid batteries are still very popular because they have a proven record in reliability. For large-scale applications, they are the most economical choice, with excellent performance and efficiency, low internal impedance, high tolerance to improper handling, and high procurement costs.
The electrolyte used in lead-acid batteries includes water and sulfuric acid, as well as an electrode plate composed of sponge lead (negative electrode) and lead oxide (positive electrode). The important type of lead-acid battery is valve regulated lead-acid battery (VRLA), also known as "sealed" or "maintenance free" battery.
Valve regulated lead-acid batteries (VRLA) are sealed, but have a valve that can discharge the accumulated gas inside into the atmosphere. Usually, do not directly maintain and do not add water, as the hydrogen released during the charging process will recombine with oxygen internally to form water. There are two important types of valve regulated lead-acid batteries (VRLA) on the market, with the difference being the electrolyte mixture: the electrolyte of the glass microfiber separator (AGM) battery is kept in a highly porous microfiber glass separator; The electrolyte gel of the gel battery is composed of a mixture of sulfuric acid and silicon dioxide.
UPS power supplies typically use AGM type sealed valve regulated lead-acid batteries (VRLA) because they have lower internal resistance, higher specific power and efficiency, lower self discharge rate, and lower procurement costs. The charging speed of glass microfiber separator (AGM) batteries is faster and can supply large current for a short period of time.
The plate of a rich liquid lead-acid battery is immersed in an acidic electrolyte. Due to the lack of sealing, hydrogen gas generated during operation will be directly discharged into the environment, and its ventilation system must be more powerful than sealed valve regulated lead-acid batteries (VRLA). In most cases, the battery pack is housed in a dedicated room. Rich liquid lead-acid batteries must be operated upright and manually filled with water.
Compared with sealed valve regulated lead-acid batteries (VRLA), they have longer service life and higher reliability. The lead-acid battery room must be maintained at a reasonable and constant temperature (20-25 ° C) to prevent shortened service life and even damage.
Lithium ion batteries
In lithium-ion batteries, the "cathode" is usually a metal oxide, while the anode is usually porous carbon graphite. Both are immersed in a liquid electrolyte made of lithium salts and organic solvents.
UPS power supplies typically use AGM type sealed valve regulated lead-acid batteries (VRLA) because they have lower internal resistance, higher specific power and efficiency, lower self discharge rate, and lower procurement costs. The charging speed of glass microfiber separator (AGM) batteries is faster and can supply large current for a short period of time.
The plate of a rich liquid lead-acid battery is immersed in an acidic electrolyte. Due to the lack of sealing, hydrogen gas generated during operation will be directly discharged into the environment, and its ventilation system must be more powerful than sealed valve regulated lead-acid batteries (VRLA). In most cases, the battery pack is housed in a dedicated room. Rich liquid lead-acid batteries must be operated upright and manually filled with water.
Compared with sealed valve regulated lead-acid batteries (VRLA), they have longer service life and higher reliability. The lead-acid battery room must be maintained at a reasonable and constant temperature (20-25 ° C) to prevent shortened service life and even damage.
Lithium ion batteries
In lithium-ion batteries, the "cathode" is usually a metal oxide, while the anode is usually porous carbon graphite. Both are immersed in a liquid electrolyte made of lithium salts and organic solvents.
Nickel cadmium battery
The electrodes of nickel cadmium batteries include nickel hydroxide (positive electrode plate) and cadmium hydroxide (negative electrode plate). Nickel cadmium batteries have a long working life (up to 20 years) and can withstand extreme temperatures (-20 ° C to 40 ° C). They also have a high cycle life and good resistance to deep discharge. Other benefits are related to low internal resistance, which provides high power density and fast charging capability. Nickel cadmium batteries can provide longer storage time and high protection to prevent improper handling.
However, the cost of nickel cadmium batteries is much higher than that of traditional sealed valve regulated lead-acid batteries (VRLA). In addition, due to the toxicity of nickel and cadmium, the cost of battery treatment/recycling process is high. Nickel cadmium batteries also need to be maintained by adding water, especially in high cycle applications or at high charging rates in certain charging methods.