EBike Battery Rebuild - 24v lifepo4 battery pack

This Instructable is not about teaching you how to rebuild your own electric bike battery, but about teaching you why not rebuild your battery.
Just finished a month-
I have a list of painful lessons to share, and all that adds up is a suggestion: do this if you can buy a new lithium battery pack for your electric bike.
There's a lot going on in your electric bike bag, welding batteries is a picky business and requires specialized equipment that is not good for other things and the end product is unlikely to be truly reliable, it is also unlikely that it will last for a long time, the possibility of a fire or explosion is real, and maybe you can learn more from other projects.
Are you still reading?
Okay, let's get into it.
The large and heavy brick that powers your electric bike is a set of battery packs that are connected in series with the controller, control the way each battery pack is charged and monitor the performance of the battery while charging and discharging
Each battery pack itself is made up of a single battery (which is what most people think is "battery", AA, AAA, what do you have ).
To rebuild such a package, the main steps are as follows: Be sure to take a lot of photos and movies for reference and record the appropriate voltage measurements throughout the process.
If you take on the project, you will face two big challenges.
First, the new battery must copy the old one on every detail.
The controller expects a specific voltage under certain conditions and is more or less sensitive to temperature.
It's also important that you handle a lot of electrical connections in a small space and a lot of power, so shorts are not possible. . .
It is surprising, however, that one may say that "shocking" may happen.
Exact count.
But this is the second one that is very difficult.
Heat is harmful to the battery, but the heat generated by the current is what you use to weld the battery to the metal strip, which will conduct electricity between the batteries.
Welding as strong as possible is important, but you have to inject as little heat into the battery as possible.
Too much heat, you will degrade or even pierce the battery, too little, in the end you will get a weak weld, and in the end, there is a loose connection inside your building, although the results are unpredictable, they are not helpful.
You're going on a thin line.
What's worse, there are many factors that affect the quality of welding: the cleanliness of the welding surface;
Thickness and shape of the electrode;
The position between them;
The degree of firmness of contact between them and the welded metal and between the metal and the battery below;
Length of time allowed for welds;
Metal quality near welding point;
There may be other factors.
Also, accurate calculation. . .
But how do I use these variables in hundreds of welds to achieve accuracy?
Consider a few tricky parts of a package that is under construction above.
Curved metal, lots of insulating tape, punctured batteries.
These are not the product of carelessness, which is the inevitable result of using amateur equipment (manual, portable welder, not computer)
Industrial control;
Replace bulky with scissors
Heavy laser cutting ).
But maybe you like to challenge, play the loser without the chance of hope.
Here are some suggestions if you have to, because you insist on going on: good luck, Brave creator, and better project than mine!