Sony Ericsson Z710i battery

SaferProducts.gov consumer incident report 20140128-E49C6-1384074. Severity: Incident, No Injury. Product: Sony Ericsson Z710i battery (Sony Ericsson Z710i battery). Incident: Dear Sony Mobile, This is the only e-mail address I could find on your website so I'm sending this to you. Please forward to your vigilance or product safety department. We have had an old but well kept SonyEricsson Z710i mobile phone as a spare in a closet. Now we needed to use it and charged it overnight. To my surprise, I found that the battery had popped out of the phone (back cover had come off) the next day. When I looked at the battery in more detail I realized the battery had swollen/expanded. Please see attached photographs for details and serial numbers etc. I believe the phone was purchased in the USA sometime between April 2007 and June 2008. The battery is the original in-box battery that came together with the phone. It has not been short circuited but has remained in place in the phone and the phone has been stored at room temperature and humidity and protected from dust etc. Please let me know if you want to investigate the battery in more detail? Best regards, [REDACTED]