JF,
Let me ask what kind of lithium battery are you talking about? It's been a
few years since I really worked on the things, but here are some comments.
Lithium batteries can have either a solid or a liquid cathode.
Some liquid cathode types cannot be shorted, as in a solder wave, since
they can support high enough current to heat the battery and break its
seal.
The solid cathode batteries can take wave solder, since they can only
supply a large current for a relatively short time before becoming
polarized, with attendant increase in internal resistance. So they don't
heat up or even lose much of their energy. As long as they don't
immediately go into an application, the batteries can recover from
polarization and work OK. Consumer-type lithium batteries have solid
cathodes, polycarbonmonofluoride or manganese dioxide as in the standard
flashlight battery. Electrolytes are organic liquids, with low
conductivity, since anything aqueous would react with the lithium, vigor
ously. The seal is a polymeric material, a grommet, which can be broken
with comparative ease, although some kind of damage would like be evident
if it were being broken with any frequency.
Your battery manufacturer has, doubtless, done tests of solderability.
Perhpas my comments can help you in your discussions with him. Lou Hart
-----Original Message-----
From: Bissonnette, Jean-Francois [SMTP:[log in to unmask]]
Sent: Thursday, May 24, 2001 4:06 PM
To: [log in to unmask]
Subject: [TN] Soldering batteries on boards
Hello Technetters,
Is there any knowledgeable person that can tell me the do's and the don't
of
soldering
a lithium battery on a PCB? Is there any manipulation that could shorten
the life
of the battery (other than the obvious leads short....)
We assemble a PCB with such a battery on it and it seems that some of them
die
after 50% to 75% of their expected life span. The board are coated with
silicone coating
after assembly, and their does not seem to be any leaking according to the
tests perform
before shipping.
Thank for any input
JF
WABTEC CORPORATION CONFIDENTIALITY NOTE
The content contained in this e-mail transmission is legally privileged and
confidential information intended only for the use of the individual or
entity named herein. If the reader of this transmission is not the intended
recipient, you are hereby notified that any dissemination, distribution, or
copying of this transmission is strictly prohibited.
<< File: ATT00004.htm >>
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
