YouTube - MiniDisc Repair - Sony MZ-E95 - Modern Replacements for Sony's First Li-ion Polymer-powered Portable Player

Disclaimer: Working with Li-po battery packs can be dangerous - compressing or bending them can break the internal layers resulting in fire risk. Currently, I do not recommend these batteries since the fit is too tight.

Sony's MZ-E95 was the world's first portable MiniDisc player with a Li-ion polymer battery that allowed for flat, compact shapes. The body is very much like the gumstick-using MZ-E75.

It came with a nice drop-in charging dock and a cool LED strip on the top lid that showed charging status.

As you can imagine, these original batteries are long dead, but there are some replacements listed on AliExpress.

A friend sent me three MZ-E95s and three sets of batteries to see if they could be replaced like they claimed.

Spoiler alert: they work, but not without some minor squeezing and modifications. 

As always, be super careful working with Lithium batteries! It wasn't too long ago that Samsung's Galaxy Note 7 phones were infamous for catching fire due to a battery terminal defect, resulting in a global recall.

After tucking some excess wire away, I was able to fit them in properly (but tightly). Please check out the YouTube video for the details!

I added some extra foam padding to keep the packs away from the switches.