Many of you will have read the 50cycles article on the choice of Phosphate technology for the eZee Li-ion battery on safety grounds, with it's references to the dangers of Cobalt batteries. The fact is that cobalt based batteries have been the mainstay for the last ten years and countless millions are in safe use around the world, and I have one nearing a decade old which is still in service. The subject has arisen because of some much publicised laptop battery fires, almost all due to batteries from one manufacturer, and caused by plain bad manufacturing. The fault was that metal particles were adrift in the electrolyte which pierced separator material, causing ignition.
Cobalt based batteries are indeed more likely to do this if badly manufactured, but I don't think that should have caused anyone to stop using them, they haven't killed anyone. Some years ago, cans of corned beef were produced with improper sealing, causing bacterial contamination which killed many people, but we didn't stop producing canned food, we just put the problem right. So why am I so concerned about this? It's because we've been cheated, batteries using lithiated metal phosphate cathodes have only 75% of the capacity of cobalt based ones. In other words, my typical 15 mile range on the Torq could have been 20 miles. That's why the eZee 10 A/h Li-ion batteries have so little gain over the 9A/h NiMh ones, they should have been over 13 A/h. That's a lot to lose just because a manufacturer in another industry messed up.
This is made worse because there's no realistic prospect of more range from current developments. I've seen, as I'm sure you have, excited reports of greatly increased range from Lithium Polymer and the like, but in fact these are rubbish. Lithium Polymer isn't going to bring any appreciable range gain since that's not what it's about. Like all current battery research, it's about faster charging, the search for more capacity through density being all but abandoned. Here's the reason why that is. Nickel Cadmium (NiCad) batteries are low density and low capacity in consequence, but are able to charge and discharge at almost instantaneous rates, subject to being kept cool enough. Nickel Metal Hydride (NiMh) are much higher density and capacity, but lose some of the NiCad ability for fast charge and discharge. Lithium Ion density and capacity is very high but the density impedes the flow of current, so charging is slow and in high drain conditions they're unable to deliver current fast enough, something our Torq batteries suffer from. We call that chemical exhaustion, so manufacturers obviously cannot go any further down the density/capacity street at present, it's a dead end.
Hence the change in direction, and Lithium Polymer is the first step, having returned to LOWER density to aid fast charging and discharge. So why is fast charging the new pursuit of battery manufacturers? It's that holy grail, the electric car. It's obvious that high capacity batteries and 300 mile ranges for cars aren't anywhere on the most distant horizon, so the answer has to be the ability to recharge at lightning speeds during journeys. Big strides have been made in this, Toshiba having already achieved one minute charging of experimental cells, with others close on their heels, and they've said the main application will be transport. It's all very sad news for electric bike users though, since fast charging isn't our current problem, it's very much range. In the future, many fast charge stations along routes will solve the problem, and in London there's already free battery charging provision in some car parks with facilities intended for all electric vehicles, not just the Riva cars that are in use at present. But it'll be many years before we get a network of roadside stations to go with a new generation of batteries.
Cobalt based batteries are indeed more likely to do this if badly manufactured, but I don't think that should have caused anyone to stop using them, they haven't killed anyone. Some years ago, cans of corned beef were produced with improper sealing, causing bacterial contamination which killed many people, but we didn't stop producing canned food, we just put the problem right. So why am I so concerned about this? It's because we've been cheated, batteries using lithiated metal phosphate cathodes have only 75% of the capacity of cobalt based ones. In other words, my typical 15 mile range on the Torq could have been 20 miles. That's why the eZee 10 A/h Li-ion batteries have so little gain over the 9A/h NiMh ones, they should have been over 13 A/h. That's a lot to lose just because a manufacturer in another industry messed up.
This is made worse because there's no realistic prospect of more range from current developments. I've seen, as I'm sure you have, excited reports of greatly increased range from Lithium Polymer and the like, but in fact these are rubbish. Lithium Polymer isn't going to bring any appreciable range gain since that's not what it's about. Like all current battery research, it's about faster charging, the search for more capacity through density being all but abandoned. Here's the reason why that is. Nickel Cadmium (NiCad) batteries are low density and low capacity in consequence, but are able to charge and discharge at almost instantaneous rates, subject to being kept cool enough. Nickel Metal Hydride (NiMh) are much higher density and capacity, but lose some of the NiCad ability for fast charge and discharge. Lithium Ion density and capacity is very high but the density impedes the flow of current, so charging is slow and in high drain conditions they're unable to deliver current fast enough, something our Torq batteries suffer from. We call that chemical exhaustion, so manufacturers obviously cannot go any further down the density/capacity street at present, it's a dead end.
Hence the change in direction, and Lithium Polymer is the first step, having returned to LOWER density to aid fast charging and discharge. So why is fast charging the new pursuit of battery manufacturers? It's that holy grail, the electric car. It's obvious that high capacity batteries and 300 mile ranges for cars aren't anywhere on the most distant horizon, so the answer has to be the ability to recharge at lightning speeds during journeys. Big strides have been made in this, Toshiba having already achieved one minute charging of experimental cells, with others close on their heels, and they've said the main application will be transport. It's all very sad news for electric bike users though, since fast charging isn't our current problem, it's very much range. In the future, many fast charge stations along routes will solve the problem, and in London there's already free battery charging provision in some car parks with facilities intended for all electric vehicles, not just the Riva cars that are in use at present. But it'll be many years before we get a network of roadside stations to go with a new generation of batteries.
