Economics, lead-acid batteries

The proper selection of the lead alloy depends on the intended use and the economics of the lead—acid battery appHcation. The metallurgical and electrochemical aspects of the lead are discussed in the Hterature in a comprehensive manner (81,85—87) as are trends of lead alloy use for manufacture of battery grids (88). 

Without any doubt the microporous polyethylene pocket will meet all requirements of modern starter batteries for the foreseeable future. Whether and to what extent other constructions, such as valve-regulated lead-acid batteries, other battery systems, or even supercapacitors, will find acceptance, depends — besides the technical aspects — on the emphasis which is placed on the ecological or economical factors. 

At the present time, a large number of spent batteries are disposed of directly into the urban waste stream without proper controls. In addition to the most common systems such as zinc-carbon, alkaline manganese and nickel-cadmium, these now include, at an increasing rate, nickel-metal hydride and lithium cells. Such disposal is of serious concern because of the possible effects of battery components on the environment. Consequently, most countries are now evolving policies for collection and recycling. The majority of lead-acid batteries are recycled, but the number of recycling plants in operation worldwide for other battery systems is still very small due to the unfavourable economic balance of such operations (see Table A3.1). Some of the procedures for the disposal and recycling of battery materials are now briefly described. 

In the economics-insensitive niche market of the luxury automobile, the development of a high-output SOFC alternative to the lead-acid battery and engine-driven alternator is well advanced at BMI/Delphi Corp (Williams, 2002). BMW is a partner in the project, which uses a Global Thermoelectric planar SOFC stack. The gain would be air-conditioner operation independent of the vehicle engine. 

New lithium-based and the more conventional Ni-Zn batteries may eventually replace lead-acid batteries as new technology and advanced manufacturing techniques reduce their costs. Metal-air batteries, both rechargeable (zinc) and nonrechargeable fuel-cell types (aluminum), may ultimately be successful as an economical primary source for short-trip transportation. The demand for increasing electronic equipment will require increased auxiliary power, which may be fulfilled by improved lithium-based and Ni-Zn systems. 

A common reason for the premature failure of batteries in RAPS systems has been the use of poor quality, or inappropriately designed, batteries. Battery choice is usually determined by economic constraints. Unfortunately, the cheaper the battery, the poorer is the performance. It should also be recognized that some system suppliers lack a fundamental understanding of the lead-acid battery. 

One hurdle to be cleared in recycling significant numbers of used Ni-Cd batteries is to assure that the batteries are amassed in convenient locations for shipping to a reclamation facility. In every country studied, this collection objective has been the hardest to accomplish. Many other recyclables are collected for their value as commodities. These materials, whether old newspapers, scrap metals or lead acid batteries, have positive economic value and are sought out by entrepreneurs seeking profit. In contrast, spent Ni-Cd batteries are useful as a source of raw materials when processed, but the combined cost of collection, transportation and processing far exceeds their raw material value. 

Although the hydrometallurgical process is more complicated than the thermal process, its principal virtue resides in the essential recovery of all of the materials in spent lead-acid batteries, including the plastic materials, and in the minimal generation of waste streams. As actufd data become available on the operational characteristics and the economics of full scale plants, it will be possible to make a meaningful assessment of this process and its merits relative to other processes for the recycling of lead-acid batteries. 

The lead—acid battery could be adequately evaluated only if compared to the other types of secondary power sources. A theoretical assessment can be made by comparing the electrical, energetic, power and economic parameters of the different sources of electricity, but the relative share of each battery chemistry in practical applications is the most objective evaluation criterion. Table 1.1 summarises the basic energy and power characteristics of six types of secondary power sources which are currently used most widely. Data from the studies of Wentzl [78] and Kohler [79] have been used. It can be seen that the lead—acid battery has inferior specific energy and power characteristics as compared to the other types of batteries. 

ENGITEC has had experience dealing with battery scrap for more than thirty years. In that time, several systems have been developed which efficiently and economically reclaim virtually every component of a spent battery. The activity of ENGITEC has been increasingly motivated by the requirements of the industry to meet the strictest environmental protection regulations. The chronologieal summary of ENGITEC s development of lead-acid battery reclamation systems is as follows ... 

To date, lithium-ion battery is the gold standard for miniaturized power supply. However, it has potential safety issues, and it is neither carbon-neutral nor renewable. Almost all other miniaturized power supplies including hydrogen fuel cells, nuclear batteries, Ni-Cd batteries, and lead-acid batteries suffer from either safety or environmental issues. MFC is a potential substitute of miniaturized power supply, for its carbon-neutral, renewable, and environmentally friendly characteristics. By applying microfabrication and microfluidic techniques, the advantages of economical mass production and large surface-area-to-volume ratio will enable MFC, a potential candidate in the miniaturized power supply. 

Secondary lead is primarily sourced from scrap lead-acid batteries but also processed scrap metallics such as sheet and pipe. Secondary operations are characterised by relatively small plants in comparison with primary smelters, and are sized to handle scrap availability within a local area. This is determined by the economics of scrap battery collection and transport to the secondary operation, and it follows that the largest secondary plants are located in the high vehicle density areas of the USA. 

The most advanced system of this complex is the sodium/sulfur battery. Cost estimates on high-temperature batteries show that after the development phase has been completed and prototypes tested, these systems may operate well inside economical margins, assuming that mass production starts. In case these vehicles and their batteries are only produced in small numbers, the same problem will be at hand, as already discussed with the lead-acid battery. A deficiency of mass production makes vehicles and batteries artificially expensive. 

A disadvantage for tubular plates is the fact that a minimum tube diameter between 6 and 8 mm is required for economic production, but the tube diameter corresponds with the plate thickness, and lead-acid batteries with such thick plates are inferior for high-rate discharge. 

Electrically-powered (lead-acid) battery driven vehicles have been used for many years in a range of applications. They have found widespread and growing employment in support services at airports and in industry, as tractors and forklift trucks, and for recreational use, for instance as golf trollies. In these off-road applications they are preferred to petrol or diesel-powered vehicles because they are cleaner, quieter and more economical. 

The ease with which materials can be identified and separated varies with the source of supply. Most automobile (lead-acid) batteries are made with PP casings. Since the metal in the batteries is reclaimed (97% reeovery in 1999), the casings represent a centralized and relatively homogeneous source of one polymer. In 1990 it was reported that almost 150 million pounds of PP were recovered annually in the United States, representing as much as 95% of all discarded batteries. About 40% of the recovered PP went into the next generation of batteries, with the balance going into other automotive products and miscellaneous consumer products [50]. Automobile tires, however, contain several different polymers in addition to the metal bead and fabric reinforcement. The reuse of tires by separating all the components is economically unsound. 

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