This study has been launched in the context of the intended substitution of cadmium containing batteries in the EU.
Approximately 2/3 of the world consumption of cadmium (ranging between 16.000- 18.000 tons during the last 30 years) is used for the production of NiCd (Nickel Cadmium) batteries. Of this about 3/4 are used in smaller-sized, sealed, consumer type NiCd cells for camcorders, household appliances, power tools, emergency lightning, etc. The remaining 1/4 is used for the production of large industrial cells mainly used in stationary and vehicular power backup systems.
With the advent of the rapidly increasing mobile phone and laptop computer markets the consumer size battery industry is undergoing substantial changes. The new battery chemistries, Nickel-Metal Hydride (NiMH) and Lithium ion (Li-ion) were introduced 1991 and 1993, respectively. The increased demand for cells, up from 1 billion 1990 to 2.5 billion year 2000, has mainly been covered by cells from the new battery
chemistries. Future mobile internet applications will further support this increase of rechargeable battery production.
In spite of the large demand for batteries, increased production facilities have lead to overproduction of certain cell sizes and rapidly reduced cell prices. If only the most standardised cells, which are also produced in large quantities are considered, then the price per Wh (Watt hour) for NiCd, NiMH and Li-ion cells have become rather similar within the last year. This phenomenon has its origin in a major restructuring of the global battery industry producing these types of consumer size cells.
In Japan, rechargeable batteries have come to be considered as strategic components among its large industrial groups Matsushita, Sanyo, Sony and Toshiba, which produce a large portion of the world’s portable equipment such as camcorder, cordless- and mobile phones, laptop computers, etc. This policy, with the backing of R&D programs for developing new batteries supported by the Japanese Ministry of
Trade and Industry (MITI) has led to a total Japanese domination in the production of rechargeable consumer size NiCd, NiMH and Li-ion cells.
Competition among the Japanese cell producers has continued to reduce the price of all these batteries but is most dramatic for the new battery types, NiMH and Li-ion.
If counted by cell numbers NiCd is still the dominant type of battery, world-wide but as the price of the new batteries comes down, an increased substitution by other types is likely.
The focus of the initial NiMH and Li-ion development was high capacity batteries for mobile phones and lap-top computers. Within this market the use of NiCd is today marginal.
On a volume basis both NiMH and Li-ion have approximately twice the capacity of NiCd. Furthermore, Li-ion being lighter than NiMH, has a weight advantage of about 30% over NiMH.
The focus on high capacity, however, makes these cells unsuitable for the use in power tool applications where NiCd still is the dominating technology.
Development of high power performance of both NiMH and Li-ion cells is, however, already made. NiMH was first. Already in 1997 the American battery producer Moltech(previous Energizer), together with Japanese power tool manufacturer Makita started to market cordless power tools with NiMH cells. Another high power application is batteries for HEV (hybrid electric vehicles) At the end of 1997 Toyota launched the HEV 'Prius' using relative small consumer size NiMH D- cells for acceleration and regenerative breaking. Sanyo and Toshiba have started to market NiMH high power batteries, too.
Japanese forecasts estimate that the NiCd and NiMH power tool cell production will be of comparable sizes by 2006. The cordless power tool market is however also increasing and a more general decline in the NiCd production is not foreseen until after 2006.
The overall cell reaction of NiMH is more simple than that of the NiCd battery type. The electrical storage capacity of the MH-electrode significantly exceeds that of the Cd- electrode whereas the Ni-electrode is essentially the same in both systems.
This will make possible performance improvements of NiMH cells beyond those of NiCd a within the group of high power batteries. Makita has today NiMH solutions for all of their cordless power tool products.
Power tools batteries represent the most demanding applications of rechargeable cells. The present general battery development is exhibiting rapid progress, too. Not only have NiMH cells started to be marketed in other typical NiCd applications such as emergency lightning, UPS systems, toys, home appliances and electrical vehicles, but other competing battery types such as Li-ion and Li-polymer have also been utilised to make prototype cells presenting even further improved performances.
With this perspective the proposed ban on the sales of NiCd or products containing NiCd cells from 2008, would seem to offer a very wide margin for the transition to alternatives. For many products this would already have been done by then.
An earlier date for the large volume products currently using NiCd cells, as described in this study would probably be more effective. Only in a few exceptional cases, such as for example emergency power systems for hospital and avionics applications, which legally may demand a verification process for new products to be used, a longer time period will be needed.