Lead-acid secondary batteries seals

Secondary batteries, sealed lead-acid, lithium-sulphur dioxide, lithium-thionyl chloride. 

Primary batteries, zinc-alkaline manganese dioxide, mercury-zinc, carbon-zinc Leclanch, magnesium types, lithium types, silver oxide-zinc, zinc chloride Leclanchd, zinc-air secondary batteries, sealed lead—acid, sealed nickel-cadmium. 

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. 

Hydrogen evolution can also be prevented, and thus the unwanted secondary reactions hydrogen evolution and grid corrosion that disturb the internal oxygen cycle in lead-acid batteries, as shown in Fig. 1.25, are not present in nickel/cadmium batteries, which therefore can be hermetically sealed so that neither vapor or gas escapes from the battery. This is the reason for the market success of these batteries in the field of portable applications. 

In battery systems based on aqueous electrolyte, water decomposition, which occurs above a cell voltage of 1.23 V, is such an unavoidable secondary reaction. But under certain conditions the resulting water loss can be avoided, and the system is used as a sealed one, as achieved with sealed nickel/cadmium, nickel/hydrogen, and nickel/metal hydride batteries. In lead-acid batteries corrosion is an additional unwanted secondary reaction with the consequence that lead-acid batteries cannot be made virtually sealed, but must have a valve, and a certain water loss cannot be prevented. 

The worldwide secondary battery market is now approximately 20 bilhon annually. A world perspective of the use of secondary hatteries by application is presented in Table 22.1. The lead-acid battery is by far the most popular, with the SLI battery accounting for a major share of the market. This share is declining gradually, due to increasing apphcations for other types of batteries. The market share of the alkaline battery systems is about 25%. A major growth area has been the non-automotive consumer applications for small secondary batteries. Lithium ion batteries have emerged in the last decade to capture a 50% share of the market for small sealed consumer hatteries, as indicated in Table 22.1. The typical characteristics and applications of secondary batteries are summarized in Table 22.2. 

Yuasa Battery Co. Ltd, 6-6 Josai-cho, Takatsukishi, Osaka-fii 569 also International Division, 12-112 Chome, Higashi-Shinbashi Minako-ku, Tokyo 105 Primary batteries, carbon-zinc Leclanchd, silver oxide-zinc secondary batteries, nickel-iron, nickel-cadmium, silver-zinc, silver-cadmium, sealed lead-acid. Sodium-sulphur, lithium-manganese dioxide. 

Secondary batteries, nickel-cadmium, sealed lead-acid, sodium-sulphur. 

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