Valve-regulated batteries

Fig. 5.15 Valve-regulated battery for standby power in telecommunications, (By courtesy of AT T Laboratories Power Systems,)...

THE VALVE-REGULATED BATTERY — A PARADIGM SHIFT IN LEAD-ACID TECHNOLOGY... 

Lead-acid batteries were first used in stationary, stand-by applications more than 130 years ago [1]. For a long period of time, only flooded lead-acid batteries were used. Nowadays, UPS and telecommunications applications use valve-regulated batteries. Large, utility-scale applications such as load levelling continue to use flooded batteries, but it seems that, increasingly, valve-regulated batteries are chosen even for these applications. 

In summary, it seems that there is a rapidly increasing market for large batteries in a variety of utility applications. So far, this has mainly been a market for flooded batteries, but it is likely that the valve-regulated battery can replace the flooded battery in utility applications in the same way that it has replaced them in UPS and telecommunications applications. 

This indicates the strong influence of overcharging on heat generation in sealed or valve-regulated batteries caused by the internal oxygen cycle. 

Lead/tin 0.2 2% Sn Valve regulated batteries, conducting elements... 

Perform float charge for batteries stored out of operation (or every 2 months a normal charge for vented batteries, and an equalizing charge every 6 months for valve-regulated batteries). 

At present, for stationary batteries, a safety distance of 0.5 m is specified according to DIN VDE 0510 Part 2. Inside this area ignition of charging gasses is possible. This applies for both vented and valve-regulated batteries. 

A frequent argument is that vented batteries require special battery rooms, but valve-regulated batteries do not. Valve-regulated batteries can be accommodated as one likes but in this sense it is not correct. DIN VDE 0510 does not require separate battery rooms. This is a requirement of the owner/user who wants to have specific protection of the supply system, e.g. in case of fire or unauthorized access. This is to ensure system functionality even in cases of crisis (see DIN VDE 0108 Safety Power Supply Systems for Public Premises , Regulations for Electrotechnical Installations in Buildings.)... 

For valve-regulated batteries new methods of measurements and monitoring are necessary. Quite a number of automatic monitoring systems have been developed in the past their reliability must be proved in the future. 

Figure 7.26 Steel rack in double decker design for vented or valve regulated batteries.

Figure 7.27 shows a way to minimize the necessary floor space that is necessary with valve-regulated batteries. In the shown rack 64 bloc batteries are arranged in eight rows one above the other, installed in horizontal position. That makes service very simple because the terminals and connectors are in front of the rack and voltage readings can easily be taken. 

Valve-regulated batteries have been use at Deutsche Telekom since the end of the 1980s. First these batteries were put into low scope purposes for testing. Their use was forced strongly with the extension of telecommunications in the new countries (area of the former GDR), so that today approximately 1700 locations (mainly cell capacities of 200 Ah up to 1500 Ah) with valve-regulated batteries are realized. Since these product series permit the use of batteries in applications in which the use of vented batteries is completely impossible, valve-regulated batteries of small capacity (bloc batteries up to 65 Ah) are used today in most facilities. Main focuses of use are converters for the transition from copper wires to glass fiber. 

Increasingly battery cabinets and battery fans hnd application in compact power supply installations. On installation, the fulhllment of the requirements of the ventilation is an essential admission criterion. Besides good accessibility of the batteries, a necessary electrolyte-resistive surface has great importance. On principle, for safety reasons acid-collecting tubes are also demanded under the installed valve-regulated batteries as for vented battery types. 

The introduction of valve-regulated batteries was accompanied by numerous problems. Many courses in the manufacturing process had to be changed and adapted for the particular case of the production of valve-regulated batteries. 

The attention to and adjustment of the correct product-specific charge voltage are of great importance with valve-regulated batteries. Furthermore, the... 

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