Used VRLA Batteries

There are many ways that ULAB can be collected. By far the most efficient is through the battery retailer, distributor, or leasing agent [7]. Either a discount is given against the purchase price of a new battery, provided that the customer returns 

THIS BATTERY SHOULD BE RETURNED TO THE RETAILER OR MANUFACTURER AND MUST BE RECYCLED 

Prior to leaving the manufacturing plant, all lead-add batteries should be labelled (Fig. 16.3) in accordance with prevailing national and international [8] regulations and with the international recycling symbol ISO 7000 1135, better known as the Moebius loop. Furthermore, there should be instructions for the recycling of the battery or a point of contact clearly displayed when it is at the end of its useful life. Each label should state, lead-acid battery , Pb or the words LEAD , RETURN and RECYCLE . If possible, the label should also have a bar code which contains information about the place of manufacture, the date of production, the battery type, and its components. 

Collection systems must be open to all sources of lead-acid batteries. For example, garages and repair shops may remove batteries from wrecked vehicles. It is important to establish a network of all businesses that might recover a battery so that there are clear instructions for delivery to the approved nearest recycler of secondary lead. 

Technical guidelines for the environmentally sound management of lead-acid battery wastes [9] were adopted by the technical working group of the Basel Convention in May 2002, and were approved by the Conference of the Parties (COP) in December 2002. Section 3.2 of the guidelines deals with collecting ULAB and advocates that  

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Tests were also performed using VRLA batteries with gelled electrolyte [9]. The additives gave benefits similar to those obtained with AGM batteries. It was concluded that the porosity additives could have a positive effect on battery capacity. Future work with these additives will continue and involve full-scale batteries. 

It is notable that, of the 17 BESSs listed in Table 10.1, the majority employed flooded batteries. Only four are known to have used VRLA batteries, namely, the SDG E, Johnson Controls, GNB-Vernon, and Metlakatla systems. The performance of the SDG E (gel) and Johnson Controls (gel) batteries appears to be not well documented in the literature. The systems date from 1992 and 1989, respectively, and the SDG E system was taken out of service about two years later. The BESS systems at Vernon and Metlakatla had AGM-type batteries. Both are still in service and seem to be performing well. These batteries date from 1996 and 1997, respectively. 

Section 3.3 of the Basel Convention Guidelines covers the safe transportation of ULAB [9]. The same recommended practices apply to used VRLA batteries. Used VRLA batteries must be considered as hazardous waste when making arrangements to either return them to the manufacturer or to transport them to the recycler. The main risk is that associated with battery electrolyte that may leak from a battery in transit. 

The trans-boundary shipment of used VRLA batteries must comply with all relevant terms and commitments made by the Conference of Parties, especially as lead-acid batteries are classified as a hazardous waste. 

Implicit under the terms set out in provision (iii), used VRLA batteries must only be shipped to a secondary lead plant known to recycle ULAB in an environmentally... 

The number of VRLA batteries used in stationary applications is increasing rapidly. They account for more than 5.2% of the total US standby power production and more than 60% of Japanese and European production. Fig. 5.15 shows a VRLA battery design for telecommunications standby power. Over the past decade, VRLA batteries have been scaled to sizes up to 3000 Ah for industrial applications. Although the original... 

Different types of lead-acid batteries have been developed as energy sources for many power applications, like traction and backup or standby power systems. The flooded lead-acid batteries have an excess or flooded electrolyte and they were the largest used at the beginning of the last century for many applications. Valve-regulated lead-acid (VRLA) batteries were developed as an alternative to the flooded lead-acid batteries, in order to maintain levels of distilled water and prevent drying of cells, which means safe operation for battery packs in electric... 

When VRLA batteries are container-formed, filling of the cells with H2SO4 solution is a delicate process, especially when using gelled electrolyte. Since the plate group is under compression, the efficacy of the filling process depends on the following parameters. 

The majority of VRLA batteries produced today are used in standby applications to provide a reliable source of power in the event of failure of the mains supply. Discharges are infrequent and the batteries are maintained by float charging at a preset voltage. For example, European practice is to use parallel strings (usually 48 V) across a 54.5 V supply (2.27 V per cell). Adequately designed new cells, after conditioning and free of impurities, have a float current of < 1 mA per Ah at 20°C. 

The AGM materials used in VRLA batteries must sustain the required plate-group pressure, must hold the electrolyte in place, and must allow sufficient (but not excessive) transport of oxygen from the positive plate to the negative. Some of the properties of typical all-glass AGM separators are shown above in Table 6.2 [7]. The following important features are noted ... 

Surface area. This can be determined using BET adsorption [11]. The significance of this parameter is that the performance of a VRLA battery is partly dependent on the surface area of the mat between the plates. For example, surface area has an influence on acid stratification. 

The function of the separator in the VRLA battery has been reviewed in Chapter 6, where the need for the separator to satisfy a complex set of requirements simultaneously has been described. The development of an elfective separator clearly represents a challenge for the materials scientist. This chapter outlines the materials that have been used to date and introduces others which are emerging as candidates during the search for improved performance. 

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