IBM Thinkpad Battery Re-Celling Battery Rebuild Tutorial

[ReCreate]

Recently I've gotten a few old thinkpads and have lots of spare 3100 mAH cells lying about, thought i'd document the process of re-celling thinkpad batteries.

Re-Celling or Battery Rebuilding is the disassembly of laptop batteries for the purpose of replacing the individual cells with new ones, making it now work as good as it did when it was new, if not significantly better. (Li-Ion battery tech has gone up 30+% in power storage in the unchanged 18650 form factor over the past 5 years alone)


The method I use for disassembling the batteries is to get a pair of snips (My favourite type is the sidecutters) and bite on a corner of the battery pack's plastic enclosure. This will sacrifice the aesthetic appearance of the battery so you should do it on a corner that isn't exposed when the battery is installed. Then you use a flat screw driver to pry the top and bottom halves of the battery apart. For more stubborn batteries, knives, hacksaws and dremels will be used. Be careful about stabbing batteries, but don't worry to much, they don't explode, they only release toxic fumes. (from experience ) So do it outside if you need to use any of these more aggressive tools.

Tips and tricks:
1 You do not need to put all the original cells it had back in. Cells in parallel can be omitted, so long as the series-configuration remains the same. A 3S battery can run with 3 cells, 6 cells, 9 cells and so forth. Cells put in parallel become one big virtual cell.

2 The cells you put in SHOULD be identical cells. Identical type, age and wear. You can get away with using different batteries, but beware, the entire pack is limited by the power of the weakest link!

3 Good cells can be harvested from HP, Dell and modern Lenovo laptop batteries for cheaper than buying the cells outright. Each cell can cost as much as $7 new. Second hand batteries can get you better deals.

4 You can solder directly onto batteries safely. You need a nice soldering iron with a HEAVY TIP! Flat tips are ideal. Soldering iron does not have to be high power, it just needs a high thermal mass on the tip!

5 Positive terminals solder much quicker and easier than negative terminals. Put a bit of flux and scratch the surface of the negative terminal before soldering. Do not hold it on there longer than a few seconds!

I'll also put the images on IMGUR for future-proofing in case if the forum's image hosting goes down.

Wiring diagram for R30 R31 R32 thinkpads
http://i.imgur.com/g0i6ZUU.png

Wiring Diagram for A22M A21P A22 & Others
http://i.imgur.com/m0uBoo4.png

[Shredder11]

Maybe you could create a video showing your tutorial in action, and upload it to YouTube?

[ReCreate]

Maybe you could create a video showing your tutorial in action, and upload it to YouTube?

Good idea. I've run out of batteries to rework at the moment but if I get more I'll do that.

[evening_hunger]

Weren't there any considerations about soldering directly on the batteries as they could explode due to temperature?

[rkawakami]

Correct. Lithium ion batteries do not like excessive heat. Batteries that already have solder tabs welded to them may be a little bit safer, if you can clamp a heat sink between the end of the tab and the battery end. Applying an iron with high thermal mass directly to the terminals could result in an explosion,