The Nickel Metal Hydride Battery Used Today In All Mass Produced Hybrids Is Higher Technology Than The Lithium Cobalt Ion Battery

Implications: The automotive press is confused or just technologically illiterate. It should not be relied upon for analysis or technology. It is OK for reporting the results of test drives and repeating what public relations flacks tell it.

Analysis: The technological basis of the lithium ion battery has been known for at least 50 years; I believe that it was Sony that first introduced this type of battery into mass production for use in personal electronics in the early 1990s. These were, as I recall, secondary (one time use) batteries, which although much more expensive than carbon-zinc dry cells lasted much longer to compensate. The rechargeable versions came much later after the introduction of laptop computers made lithium secondary batteries too expensive for that use.

It was, however, only in the late 1980s that the nickel metal hydride battery (NiMH) was invented and perfected at Energy Conversion Devices, Inc. when rechargeable nickel cadmium batteries went out of favor due to the toxic nature of cadmium, not due to inferior characteristics of the batteries.

However along with the nickel metal hydride battery came a vast increase in the utilization of metal hydrides as solid storage media for hydrogen, and of nickel metal hydride alloys as catalysts for use in fuel cells. Today a large array of metal hydride uses are contemplated or under way. In fact this field alone represents much of what is being researched today in rare earth chemistry and metallurgy. 

As for lithium battery research it has been known for more than a century that, if a lithium based battery could be built, then it would have the best potential for energy storage density by weight of any battery, because lithium is the lightest metal. The problem was and is the handling of lithium. As a metal it cannot be exposed to air, because if the tiniest amount of moisture is present-and it always is-the lithium will react immediately with the oxygen in the moisture generating enough heat to ignite the hydrogen also produced in the reaction with the oxygen present in the air.

The focus of current lithium battery technology is to effectively eliminate any metallic lithium from being formed in the system or, if it is, then to prevent it absolutely from contact with moisture and air. This is not a trivial problem to solve, and research has led to the lithium ion type of battery, which when constructed with cobalt can be made into a relatively safe high energy density storage device with more energy storage and longer utilization potential than the NiMH battery.

But, so far, in practice, the lithium ion battery has not been able to match the safety record of the nickel metal hydride battery, nor for that matter of the lead acid battery.

Even if it turns out that the problems are in the construction of the batteries it may also turn out that it is not economical to manufacture such a large device with the concomitant safety and reliability.

Lithium will not be the basis of a hydrogen storage medium nor will it be part of a fuel cell.

Certainly then it is NiMH which represents the higher and newer technology.

Oh, by the way, Toyota does its battery research in-house because it wants to maintain the competitive advantages of secrecy and proprietary knowledge and mostly because the Japanese don't like to lose face by letting the public see failures. GM on the other hand certainly doesn't seem to care what the public thinks about its current rejection of the costs of in-house development, since most people think it's a huge mistake.