Broad Outlook
In the last 25 years, the search for new environmentally-friendly alternative sources of energy, as opposed to other traditional sources, has given rise to two stars which are no longer promises but which have defined the technological path for the XXI century: fuel cells and lithium batteries and cells. This analysis will focus on lithium batteries and cells. The following generalizations should be made to continue with our analysis:
- Any reference in this article to “batteries” or “cells” will always be understood as “batteries and cells”, but considering that the literature usually refers to “batteries” when there are two or more cells electrically interconnected.
- “Batteries” will be considered to be “lithium” batteries, including all forms of lithium:
o Metallic lithium, used in primary non-rechargeable lithium batteries. They are typically used in watches, calculators, etc.
o Lithium-ion, used in secondary rechargeable lithium batteries. They are used, for instance, in cell phones, portable computers, etc. This type of batteries includes lithium polymer batteries.
During the short existence of lithium batteries, their uses have constantly extended, mainly in portable electronic equipment, given that they provide more energy and have a longer duration, as compared to other types of cells. The increasing demand of these sources of energy required increasingly smaller and more powerful cells. Thus, they could be used for cell phones, digital photographic cameras, portable computers, toys, wheelchairs, medical devices, military devices, etc.
Automobiles could not be an exception. In the latest years, automotive companies have started a fierce race to develop units driven by lithium batteries and hybrid units, propellable both by such batteries and by fuel.
In Argentina, for instance, at the beginning of this year, an agreement was announced between the Australian mining company Orocobre and Toyota Tsusho (1), in which the automotive company Toyota holds a 21.8% interest and which has business links with Sanyo and Panasonic, for the extraction of lithium carbonate in Salar de Olaroz, Province of Jujuy.
To have an idea of the importance of this agreement, the final investment for the project submitted by Orocobre to the Argentine Secretary of Mining amounts to USD 100 million, and contemplates the creation of 160-200 jobs and an annual production of 15,000 tons of lithium carbonate. Currently, the annual production of lithium carbonate in Argentine is of about 10,000 annual tons, which are obtained through the exploitation in Salar del Hombre Muerto, in the Province of Catamarca, by the company Minera del Altiplano (a subsidiary of the American company FMC Corporation). (9)
Specialists estimate that the carbon lithium production of China, one of the three countries which has 97% of the world production (the other two countries are Chile and Argentina), could reach 60,000 tons this year (2). It is, then, understood the great strategic interest on the Salar de Olaroz field.
It is not by chance that the great powers currently dispute this precious metal, now called “white gold” by many authors, through the leading technological companies.
For instance, in the Asian continent: Japan is interested in maintaining its leading position in the production of portable computers, digital cameras, mobile phones and, now, automobiles.
Instead, China prepares to carry out a different lithium revolution: they intend to take the technological lead in the manufacture of vehicles in a post-combustion engine era (the last international economic crisis originated in the United States helped the extinction of the big and heavy combustion engine-driven American cars in favor of medium-sized cars). Thus, they would not have to acquire the expertise developed during the XX century with this type of propeller and they could leverage the large lithium carbonate fields they have (3)(4).
Lithium-based energy sources are becoming prevailing in the world. Consumption is having a wonderful increase year after year in a market that expands more than 20% per year (5). This, in turn, increases transportation.
A “gold” not so noble
Without consumption, there is no transportation. And if there is lithium battery transportation, then, there are specific risks.
In 1998, the UN Committee of Experts on Dangerous Goods (the Committee) started to take into account the progress of lithium technology regarding its application to batteries, and introduced in the Orange Book the concept of “Equivalent Lithium Content” as a measure of batteries' capacity (11). This concept was used to define criteria to exempt certain batteries from transport regulations due to their low capacity. Subsequently, the latest edition of the Orange Book replaced the "Equivalent Lithium Content" with the Watts-hour number, which is easier to calculate and interpret (12).
These batteries have the capacity to generate a great amount of heat and they may even generate a fire if they are damaged, wrongly packaged or poorly manufactured. According to the U.S. Department of Transportation (DOT), approximately 1 out of 10 million of all the primary and secondary lithium batteries have defects which may cause accidents (6). The probability of an accident seems insignificant, microscopic, but the risk will still be important due to the great volume transported and, mainly, due to the catastrophic consequences that a flight loading a single defective battery capable of causing an air accident may have. If it is considered that only during 2008 3300 million cells and batteries have been transported through all transportation means throughout the world (13), the amount of cells and batteries with high probabilities of causing accidents because they are defective is more than interesting. No one would get on a plane if he/she knew that there is a cell o lithium battery in the plane which will be the cause of the plane crash.
Studies performed by the U.S. Federal Aviation Administration (FAA) revealed that those materials have a negative impact on transport safety due to the following factors (7) (8):
- Their self-ignition temperature could be easily reached if another load in the same decks sets on fire. After that temperature is exceeded, they react more violently than a regular cell or battery.
- A fire of lithium batteries, primary batteries, in particular, is harder to fight with the extinguishment methods used in aircraft cargo decks.
- In the case of primary batteries, the content of metallic lithium may be released melted during the battery overheating, and it may reach and affect the structures of the cargo compartments of the aircraft.
- In the case of secondary or lithium-ion batteries, their overheating causes the release of the flammable liquid mix which contains the electrolytes, due to the increase in the pressure within the device. This entails two consequences:
- The liquid released will be easily scorched by the flames during a fire.
- The sudden release of flammable liquid is associated to a pressure pulse generated within the battery during the overheating. If the relief device does not work properly, the pressure pulse pushing the liquid outside may be strong enough so as to cause the battery's explosion. These explosions may also affect the structure of the deck.
So far, the references made to the risks with lithium batteries have only considered a hypothetical fire in a deck with this cargo and, though they do not generate the fire, they may be extremely dangerous. However, we have not taken into account that they may also generate overheating without being induced by any fire or external source.
The most common “natural” cause of that overheating are short circuits in the batteries (6). Once they occur, when temperature increases, they trigger several internal exothermic reactions which favor a higher increase in temperature and, therefore, in pressure. Everything ends with the release of the content and the possibility of an explosion and fire.
But why a lithium cell may have a short circuit?
The reason may be the contamination of the device during the manufacturing process or due to the cell or battery design problems, which may include physical damages due to hits or perforations, not only manufacturing problems or errors.
These are cases of internal short circuits, but there may also be external short circuits, for instance, because an electrode or a terminal comes into contact with an external metallic object. In these cases, there is also overheating.
Taking into account both internal and external short circuits, the DOT calculated that these were the cause of 72-73 % of the incidents involving lithium cells or batteries between 1991 and 2008 (6).
Certainly, abuses by users may also generate overheating, for instance, during loading and unloading processes or due to the involuntary activation of equipment containing the cells or batteries.
The Last Straw
Most of the incidents accounted had minor consequences, and the personnel involved reacted promptly.
A famous accident which involved lithium cells was the fire of UPS aircraft upon arriving to the airport of Philadelphia, United States, on February 7, 2006. There were no casualties, but action from the airport emergency staff and the support personnel of the airline and of the concerned facilities was necessary. The aircraft was totally destroyed.
The exact cause of the accident could not be identified by the US National Transportation Safety Board (NTSB), given that the evidence necessary to explain it was completely destroyed during the accident. Investigators did not find any evidence of an explosion or a fire with high temperatures sufficient to melt steel components. They did not determine either that the cause was the electrical system, as there were no rests of the electrical system in the most damaged place, and the irregularities in the flight control system were detected by the crew a few minutes after detecting the smell of burning (10).
However, it could be determined that th ere were several electronic devices in the load, which devices contained secondary lithium cells, and that these devices were in the load positions where the fire first originated.
Although investigators could not determine with certainty if the accident was caused by those lithium cells in the equipment, their presence in the scene was additional to all the other incidents caused by lithium cells and registered worldwide. Furthermore, considering the increasing world trend regarding accidents with lithium cells (which increase went hand in hand with that in their manufacturing and use), the UPS aircraft accident was the last straw.
As a result of the investigation, the NTSB recommended the U.S. Department of Transportation (DOT) to remove regulatory exemptions applicable to packaging, marking and labeling of loads of small secondary lithium batteries until completing an analysis of their failure and until the relevant actions to reduce the risks for transporting those materials have been determined. This means that: all lithium cells and batteries should then receive the same treatment for air transport purposes (except extremely small cells, with the approximate size of a button).
This is being implemented by the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA) through a new regulation, which will be effective soon (13). Several objections have been voiced against it, including that of the U.S. Portable Rechargeable Battery Association (PRBA), which includes the main cell manufacturers of the world (14). The main argument is the certainty of a significant negative impact for the American economy, as adjusting to the new regulation would imply an approximate cost of USD 1000 million, delays in the import of critical inputs for areas such as medicine, and the loss of jobs due to the relocation of the distribution centers, given the impossibility to import lithium batteries by plane.
As always, economic aspects are a barrier to any measure aiming at safety. The economic aspects may not be ignored at the time of implementing this type of measures.
However, how many resources is it necessary to invest in safety?
On one end we have the loss of jobs, logistic barriers (and, thus, difficulties to supply critical inputs) and loss of competitivity by several companies faced with the energy boom represented by lithium cells. On the other end, there is the possibility of an air catastrophe. In the middle: a defective lithium cell amongst thousand millions of ordinary lithium cells, which causes a short circuit and may generate a fire in the cargo deck of the aircraft.
The dividing line among those two ends is extremely thin.
1. Toyota participará de la extracción de litio en Jujuy [Toyota will participate in lithium extraction in Juluy], Oliver Galak. La Nación, Argentine, January 21, 2010.
2.Global and China Lithium Carbonate Industry Report, 2008-2010. http://www.researchinchina.com/
3. Cristina espera que el yuyo la saque del pantanal fiscal [China expects the weed to take it from the fiscal marsh], Jorge Oviedo. La Nación. Argentine. January 24, 2010.
4. Japan and China fight it out for right to mine lithium under Bond’s battlefield, Leo Lewis. The Times. England. June 15, 2009.
5. “El litio, el nuevo petróleo que promete revolucionar el mundo de los commodities” [Lithium, the new oil which promises to cause a revolution in the world of commodities], Martin Burbridge. http://www.elcronista.com/.
6. Enterprise Lithium Battery Action Plan. US DOT, PHMSA. www.safetravel.dot.gov/action_plan.pdf
7. Flammability Assessment of Bulk-Packed, Nonrechargeable Lithium Primary Batteries in Transport Category Aircraft, Harry Webster. Document DOT/FAA/AR-04/26 of the U.S. Department of Transportation (DOT)
8. Flammability Assessment of Bulk-Packed, Rechargeable Lithium-Ion Cells in Transport Category Aircraft. Harry Webster. Document FAA/AR-06/38 of the US Department of Transportation (DOT)
9. Los Proyectos Vienen Marchando [Projects come marching]. Emiliano Grasso, Tecnoil magazine, No. 318.
10. Aircraft Accident Report - Inflight Cargo Fire, United Parcel Service Company Flight 1307, McDonnell Douglas DC-8-71F, N748UP, Philadelphia, Pennsylvania. February 7, 2006. Document NTSB/AAR-07/07/ PB2007-910408 / Notation 7772C of the US National Transportation Safety Board (NTSB).
11. Recommendations on the Transport of Dangerous Goods, UN Model Regulations. 11th edition, Chapter 3.3, Special Provision 188.
12. Document ST/SG/AC.10/C.3/2005/13, submitted by the U.S. Portable Rechargeable Battery Association (PRBA) before the US Committee of Experts on the Transport of Dangerous Goods, in April 2005, to amend the 13th edition of the Orange Book.
13. Document Docket No. PHMSA–2009–0095 (HM–224F), issued by the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA) on January 11, 2010.
14. PRBA Urges PHMSA to Reject Lithium Battery Rulemaking And Adopt Internationally Recognized Transport Regulations. Portable Rechargeable Battery Association, March 16, 2010.
Translated by Camila Rufino, Accredited Translator
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