li-ion protection and proper charging?

[megfourfun]

I have many questions so please forgive me if this becomes long winded.

1) To start, I would like to ask about charging lithium ion and how it is done today.

http://www.batteryuniversity.com/partone-12.htm

explains the concept behind charging Li-ion but doesnt go into much detail about where the protection is done. The article mentions terminating the charge when <3% of the rated current is reached. What circuitry is used to assure this happens and where do companys put the circuitry (in the charger or in the battery?). Does this circuitry actually cut off all current to the battery at this point? Does the charger stop the charging or does the battery's built in circuitry?

2) I've also noticed other protection mentioned, including: overcurrent, short circuit, and over temperature. I'm assuming that overcurrent is met by just using a current limiting circuit, short circuit is broken by possibly a fuse or something and over temperature is some thermal cutoff device. So, the question I have is, is there a way to determine what current your battery requires via circuitry and then supply that amount? My question comes from

http://us.kensington.com/html/6368.html,

in which this device has the ability to charge multiple devices. My guess is that a micro would be required for this type of gadget to determine voltage output, how much current to source and all that. How is the battery voltage determined?

Thank you

 

[espowbattery]

1. If you do not use your laptop for extended periods of time (a week or more), remove the battery pack from the laptop.

2. Do not expose the battery to high heat or freezing temperatures. Do not leave your battery in your car in the summer. Hot batteries discharge very quickly, and cold ones can't create as much power.

3. Make sure to plug your laptop charger adapter into a UPS and not directly into a power outlet or surge protector.

4. If you have a nickel-metal hydride battery, completely drain and recharge the battery once a month to maximize its capacity to hold a charge.

5. Fully charge new battery packs before use. New pack needs to be fully charged and discharged (cycled) a few times before it can condition to full capacity.

6. For laptops that work as Desktop Replacement, the battery should be re-installed every 3-4 weeks and allowed to fully discharge.

7. Leaving a battery in a laptop while using an electrical outlet for long periods of time will keep the battery in a constant state of charging up and that will reduce the life cycle of the battery.

http://www.hp-laptop-batteries.net/