Google Answers Logo
View Question
 
Q: Li-ion Battery Topology ( Answered 3 out of 5 stars,   2 Comments )
Question  
Subject: Li-ion Battery Topology
Category: Miscellaneous
Asked by: microi-ga
List Price: $2.00
Posted: 28 Dec 2005 13:27 PST
Expires: 27 Jan 2006 13:27 PST
Question ID: 610623
What is the 3rd terminal on a typical Li-ion battery used for? I am
planning to create a battery pack and therefore need to build a CV
charger.

Clarification of Question by microi-ga on 28 Dec 2005 13:30 PST
The battery pack I plan to build will be constructed of two cell phone
batteries. These batteries typically have three terminals: one (+);
one (-); and a third unmarked.  The unmarked terminal is the subject
of this question.
Answer  
Subject: Re: Li-ion Battery Topology
Answered By: hedgie-ga on 29 Dec 2005 01:16 PST
Rated:3 out of 5 stars
 
Please do note: 
"
Warning
If you are not completely sure what you are doing, don't apply what is
described below. In any case www.electronics-lab.com does not have any
responsibility in any way to the consequences that this guide may
have. Read it at your own risk. Please don't continue reading if you
don't agree with the above.
.....


4. The thermistor (usually PTC) that measure the battery temperature
inside the pack. It's terminals are connected to the charger so it can
sense the temperature of the pack and control the charge current until
the battery it's full charged."
http://www.electronics-lab.com/articles/Li_Ion_reconstruct/



Of interest?
http://www.faqs.org/faqs/pc-hardware-faq/laptops/compaq-aero/section-67.html


bonus link
http://www.discovercircuits.com/B/batt-chrg.htm

comment: Good guess kottekoe. Just  add few  'links' to your knowledge
- and you got it made :-)

Request for Answer Clarification by microi-ga on 29 Dec 2005 14:06 PST
Is a schematic of a charger which has a temperature sensing terminal available?

Clarification of Answer by hedgie-ga on 29 Dec 2005 23:51 PST
Unless there is one in the bonus link, I do not know of any.

Clarification of Answer by hedgie-ga on 30 Dec 2005 00:01 PST
Try search terms: charger battery thermistor

which leads to 
://www.google.com/search?hs=pTE&hl=en&lr=lang_en&safe=off&client=opera&rls=en&q=charger+battery+thermistor&btnG=Search

e.g

http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1037,C1078,C1088,P8990&action=featur

Clarification of Answer by hedgie-ga on 05 Jan 2006 13:50 PST
I am wondering what it would take to earn 4 stars from  microi-ga.

 I see this is your first question here, microi-ga,

so,  I welcome you to GA and want to give you few more links to look at:

http://answers.google.com/answers/pricing.html

http://answers.google.com/answers/faq.html

guide
http://www.christopherwu.net/google_answers/answer_guide.html




cheers

Hedgie

Request for Answer Clarification by microi-ga on 06 Jan 2006 08:34 PST
Hedgie,

On reconsideration, your response is a 4 star response.  How do I
modify the rating?

Mack

Clarification of Answer by hedgie-ga on 06 Jan 2006 17:07 PST
You can not. 
That's OK. Let's both do better next time.
Hedgie
microi-ga rated this answer:3 out of 5 stars
Good answer, fairly throough with pointers to additional related material.

Comments  
Subject: Re: Li-ion Battery Topology
From: kottekoe-ga on 28 Dec 2005 21:45 PST
 
Two guesses:

1) Two power wires, plus a third terminal for a temperature sensor.
Lithium batteries can be very dangerous, so I think some of them have
a built in sensor to turn off the charger if they overheat.

2) A center tap? Some electronic systems require a ground reference
and both a positive and negative supply relative to that ground.
Perhaps the third wire is the ground connection. If so, it would
likely be colored green.


My guess is on answer #1, but it is only a guess.
Subject: Re: Li-ion Battery Topology
From: magnesium-ga on 07 Jan 2006 17:37 PST
 
Looks like a 5-star answer to me. Excellent work, Hedgie-ga.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at answers-support@google.com with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  


Google Home - Answers FAQ - Terms of Service - Privacy Policy