Li-ion batteries contain a protection circuit that shields the battery against abuse.This important safeguard has the disadvantage of turning the battery off if over-discharged,and storing a discharged battery for any length of time can do this.The self-discharge during storage gradually lowers the voltage of a battery that is already discharged;the protection circuit will eventually cut off between 2.20 and 2.90V/cell.
One of the biggest problems in developing hybrid cars is the pesky lithium battery.The technical problems associated with the Li-Ion battery have plagued manufacturers almost forever – whether it’s vendors selling notebooks or car companies attempting to green the planet.Fuel cells held out a lot of promise but the hype surrounding these cunning devices has clouded the fact that they’re not really that viable for many applications.Even mighty chip firm Intel has got all hot and bothered about Li-Ion batteries and fuel cells from time to time.
Now Hitachi – motto Inspire the Next – has come up with an idea which may turn the Li-Ion battery into a real cool cat.According to Nikkei,Hitachi has created a Li-Ion battery with an output per kilogram of 4,500 watts.That’s 70 percent more than the batteries it’s currently churning out,and 50 percent more than a battery it will mass manufacture next year.When can we expect to see this new and improved Li-Ion? Sometime after 2010,Hitachi promises.The other good thing is that the battery will last 10 years,so will keep pace with the anticipated life of a hybrid car.
Some battery chargers and analyzers,including those made by Cadex,feature a wake-up feature or “boost” to reactivate and charge batteries that have fallen asleep.Without this feature,a charger would render these batteries as unserviceable and the packs would be discarded.The boost feature applies a small charge current to first activate the protection circuit and then commence with a normal charge.Do not boot lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer.Copper shunts may have formed inside the cells that can lead to a partial or total electrical short.
When recharging,such a cell might become unstable,causing excessive heat or showing other anomalies.The “boost” function by Cadex halts the charge if the voltage does not rise normally.A study done by Cadex to examine failed batteries reveals that three out of ten batteries are removed from service due to over-discharge.Furthermore,90 percent of returned batteries have no fault or can easily be serviced.Lack of test devices at the customer service level is in part to blame for the high exchange rate.Refurbishing batteries saves money and protects the environment.