Hello and welcome to Apple Support Communities Ipod2424,
Thank you for contacting us. You have come to the right place and we are happy to assist you. We understand you're inquiring about your iPod battery. We can understand why you’d reach out for a solution. You have the iPod classic 160GB and has a built-in rechargeable lithium ion battery. Apple made the iPod classic 120GB & 160GB between 2007-2009, but was never referred to as generation, just iPod Classic. You may be able to get it serviced with a new battery at an Apple Authorized Service Provider, but the iPod Classic is considered obsolete.
Obtaining service for your Apple product after an expired warranty
Thank you for contacting Apple Support Communities.
Best regards.