Purpose-built batteries

Purpose-built batteries. Gel batteries with either tubular plates or thick, flat plates ( 5 mm) are recommended when a long cycle-life is required. Both designs have a high level of resistance to positive-plate degradation, and can tolerate high levels of positive-grid corrosion. 

Many manufacturers around the world offer tubular-plate gel batteries for heavy-duty RAPS operations. As the name suggests, the batteries have tubes that contain the plate material. This design is employed only for the positive plates, as these are 

The grids of both flat-plate and tubular batteries should not contain antimony or any other additive that may decrease the hydrogen overpotential of the negative electrode. Indeed, it is recommended that ultra-pure lead be used to manufacture both the grids and the active material in order to avoid the possibility of excessive self-discharge at either the positive or the negative plates. 

The batteries should be able to dehver at least 1600 discharge cycles to 80% DoD (5-h rate at 25°C failure when capacity 75% of nominal). Also, the self-discharge of the batteries should not exceed 3% of the rated C capacity per month (at 25°Q. 

If batteries are to be operated at elevated temperatures for extended periods, the relative density of the electrolyte should be decreased appropriately (generally to between 1.260 and 1.240). For low-temperature applications, batteries should have a large volume of electrolyte of high relative density to minimize the likelihood of freezing, and compressible separators and/or spacers that can absorb expansion should freezing and related expansion occur. The gel battery is considered to be the most appropriate VRLA technology for this task, as it can be constructed with an excess of acid. It also uses microporous separators, which should reduce the likelihood of short-circuits if the electrolyte were to freeze and expand. 

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There have been a small number of reports published recently that describe the development of purpose-built batteries for RAPS systems. A VRLA battery for use in PV power systems has been described by Shiomi et al. [27]. The negative plates contain a high level of carbon, but the particle size and concentration of the additive are not described. The recommended level of carbon is simply given as ten times normal levels . The type of VRLA battery used in the experiments is also unclear. Batteries with and without the additional carbon were operated under simulated PV duty for extended periods. Increasing the carbon by ten-fold was found to extend the cycle-life of the batteries from 400 to 1000 cycles. This improvement was attributed to the formation of a conductive network of carbon around the peripheries of lead sulfate crystals. The subsequent increase in conductivity was claimed to improve the rechargeability of the negative plates and, thereby, to suppress the accumulation of lead sulfate. 

Most major producers of mercury—zine eells and batteries use a vented construction, which renders their products leakproof and free from bulging under all normal working conditions. Sell-venting oeeurs automatically if, for example, excessive gas is produeed within the cell under sustained short-eireuit eonditions. This type of cell is manufactured in a wide variety of structures to provide batteries of varying size, voltage and capacity. A wide range of purpose-built batteries can also be obtained. For maximum reliability intereell coimection is by spot welded strips of niekel-plated steel. Outer containers are made from materials ranging from cardboard to metal. 

A starter or contactor with manual push-button or thermostatic operation to start and stop the fan normally controls simple systems. More complex systems that incorporate components that need control or monitoring are normally operated from purpose-built central control panels. The most common functions provided are fan motor stop, start and speed control, damper control, filter-condition indication and heater battery control. For optimum control, the system should be automatically controlled from thermostats or other sensors and a timeswitch. 

Lower-cost batteries. For applications that do not require both a long cycle-life and a high level of reliability under extreme conditions, less expensive, standard fiat-plate, gel batteries can prove cost-effective. These batteries typically provide 800 cycles to 75% DoD, which is half that of the purpose-built designs. This reduction in cycle-life is primarily related to the use of less robust positive plates (typically 3-mm thick) and less attention to detail in the general construction of the... 

Edison Batteries for New Ford Cars Automobile Man Discusses Possibilities of New Storage Systems with Its Inventor, The New York Times (January 11, 1914). According to the article, Henry Ford also said, Mr. Edison and I have been working for some years on an electric automobile which would be cheap and practicable. Cars have been built for experimental purposes, and we are satisfied now that the way is clear to success. ... 

Detector tubes are operated in conjunction with a hand pump or battery operated pump that draws ambient air into the tubes (see Figure 10-4). To sample the air, both ends of the tube are broken off in the special slots built into the pump body for that purpose, and the tube is inserted in the pump in the proper direction. An arrow on the tube indicates... 

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