Nickel-lead system, application

Because the nickel—iron cell system has a low cell voltage and high cost compared to those of the lead—acid battery, lead—acid became the dominant automotive and industrial battery system except for heavy-duty applications. Renewed interest in the nickel—iron and nickel—cadmium systems, for electric vehicles started in the mid-1980s using other cell geometries. 

Nickel battery systems compete directly with the lead acid battery in many commercial energy storage applications and with Li-Ion in portable electronic applications. 

Today the most important electrochemical storage systems for stationary applications are the lead-acid and the nickel/cadmium systems. Both of them have advantages and disadvantages which carefully have to be considered for best selection. 

Largely for reasons of cost, low maintenance requirements and proven technology, lead-acid batteries continue to dominate the traction battery market. The closest competitors, in specialist applications, are various nickel-based systems. For stationary batteries, used as a standby power source, the market is more closely divided between lead-acid and nickel-cadmium batteries. At the same time, new applieations have opened up in recent years for lead-acid batteries in electric-powered support vehicles (in recreational and industrial uses) and a potentially large new market in electric cars beckons (see Chapter 18, for a discussion of this and other new... 

For many everyday battery applications, the choice is still between the lead-acid and the nickel-cadmium systems, rather than the more recently developed systems. Each of these two main types of sealed battery has its own advantages and the choice between nickel-cadmium and lead-acid batteries depends very much on the particular application and on the performance characteristics required. 

In acidic electrolytes only lead, because it forms passive layers on the active surfaces, has proven sufficiently chemically stable to produce durable storage batteries. In contrast, in alkaline medium there are several substances basically suitable as electrode materials nickel hydroxide, silver oxide, and manganese dioxide as positive active materials may be combined with zinc, cadmium, iron, or metal hydrides. In each case potassium hydroxide is the electrolyte, at a concentration — depending on battery systems and application — in the range of 1.15 - 1,45 gem"3. Several elec-... 

In electronic applications, where it is common to deposit copper and/or copper alloy and tin in sequence, with a nickel diffusion barrier layer, 0.5 fim thick, between the layers present, no failure occurs. Without the nickel layers between bronze/-copper/tin layers themselves, for instance, intermetaUic brittle layer(s) and Kirkendall voids are formed, leading eventually to separation of the coated system and substrate. 

Chemical precipitation is applicable to most heavy metals likely to be found in contaminated gronndwater. Examples of metals that have been removed to a concentration of less than 1 ppm inclnde cadminm, chrominm, nickel, zinc, manganese, copper, tin, iron, arsenic, lead, and mercnry. Chemical precipitation is widely nsed to meet National Pollution Discharge Elimination System (NPDES) reqnirements for the treatment of heavy-metal-containing wastewaters. In many cases, metals precipitation may also be nsed as a pretreatment step prior to discharge of the wastewater to a pnblicly owned treatment works (POTW). 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

Stationary battery (cell) — Rechargeable -> batteries designed to be located at a fixed place. Stationary batteries are used mainly for uninterruptible power supplies (UPS) and standby applications. These cells are usually designed for high reliability and very long -> cycle life under shallow depth of discharge (DOD) conditions. The common chemical systems utilized for the production of stationary batteries are the -> lead-acid and -> nickel-cadmium batteries. Less common, and more futuristic is the - sodium-sulfur battery designed for KW and... 

Apart from its historical interest, this brief survey over the centuries from 1800 to 2000 helps underscore the fact that key developments in battery research and technology have always come in response to specific sector demands that have in turn followed signal scientific advances. Nowadays, the three main rechargeable systems are the lead-, nickel-, and lithium-based batteries. While the first two, with their roots in the last century, are undergoing continual refinement to improve their performance in today s applications, the last is the result of the most recent research into new materials and the one that offers greater expectations. 

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