Safety problems with batteries

The shipment, use, and disposal of rechargeable lithium batteries are regulated, as for the primary lithium batteries, by international organizations, government agencies, and quasigovernment institutions because of the concern for potential safety problems with lithium batteries, particularly if they are physically or electrically abused. ... 

To avoid the problems associated with lithium metal, lithium insertion materials (e.g., graphitic carbons) are being investigated as negative electrodes. With respect to lithium metal, the use of negative insertion materials improves the cycle life and safety of the battery but lowers the cell voltage, the theoretical specific capacity, and the charge transfer rate [104]. 

At this stage of development, it is doubtful whether a flywheel incorporated in an electrical highway vehicle can replace lead acid batteries due to problems with vibration and safety, but the performance of a lead acid battery deteriorates in hot wet conditions, requires frequent maintenance and has a life expectancy of only about 4 years. The aim of US Flywheel Systems, however, is to drive a car with a flywheel system. It is reckoned that some 16 units would be required to fulfil this objective and adequate protection would have to be supplied, since, in the event of a wheel disintegrating, it would dissipate its energy into hot fluff and high speed dust. A very sophisticated computer control system is used to filament wind each wheel with a high fiber content of 86% w/w [89]. 

The assembly of these cells into a battery must take account of electrical engineering considerations, thermal control problems, questions of accessibility and maintenance and safety factors. With as many as 500-1000 cells involved it is evident that a series/parallel network will be required the design of this network poses particular problems for Na/S cells because of two characteristics they possess ... 

Li metal originally suffers from the dendrite growth problem that causes shorter life and safety problem. This point is not discussed in this article as so many reports and reviews can be found elsewhere. Li electrode in Li-S battery has inherent problem. As stated in redox-shuttle mechanism of polysulfides in Fig. 1, reduction of polysulfides at the Li electrode surface is a problem. If polysulfides are deposited as Li2S, capacity is lost and Li electrode efficiency becomes worse. It is very important to prevent Li2S deposition on the Li electrode to maintain cycles. Solid electrolyte is a one solution however, brittle solid electrolyte caimot tolerate the volume change of Li electrode. Practical way to improve is thought to be a use of electrolyte additives. LiNOs is well known to depress the redox-shuttle phenomena [19]. The effect of this additive was concluded in the paper as a formation of protective layer on Li surface. LiNOs possibly oxidized the polysulfides and at the same time, formed the film by decomposition of itself. As a result, polysulfides were prevented from contacting with Li electrode. 

Discharging multicell series-connected batteries to too low an end voltage, however, may result in safety problems. It is possible, in this situation, for the poorest cell to be driven into voltage reversal. With some batteries this could result in venting or rupture. 

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