For once it's not a Sony battery being recalled, but it is a huge number. 46 million BL-5C batteries made by
Matsushita are being recalled by Nokia because of possible overheating. Replacements will, of course, be free. The batteries were manufactured between
December 2005 and November 2006.
Nokia has identified that in very rare cases the affected batteries
could potentially experience over heating initiated by a short circuit
while charging, causing the battery to dislodge. Nokia is working
closely with relevant local authorities to investigate this situation.
Consumers with a BL-5C battery subject to this advisory should note
that all of the approximately 100 incidents have occurred while
charging the battery. According to Nokia's knowledge this issue does
not affect any other use of the mobile device. Concerned consumers may
want to monitor a mobile device while charging that contains a BL-5C
battery subject to this product advisory.
I'm not sure what they mean by "dislodge" but that's what their website says. You can determine
if your battery needs to be replaced
by entering a battery code at the above linked Nokia site. Note that it may be hard to reach that site as there's a huge load on it right now.