Perfect example:

http://www.gizchina.com/2013/09/18/exclusive-hands-video-sta...

http://www.gizchina.com/2013/09/24/jiayu-g5-teardown/

Almost identical in dimensions and appearance to an iPhone 5, yet has expandable storage and a 50% more capacity removable battery. If some small Chinese company can make such a phone, so could Apple, but they deliberately chose not to.

How many g5 batteries exploded on their owners with third party batteries, most of which are crappy?

It's easy to make anything if you have lax enough standards.

How many Samsung devices exploded on their owners with first-party batteries? This is a ridiculous argument -- what aspect of a "non crappy" battery will result in a replaceable version being more bulky?

Obviously the part where non-replaceable batteries are also more expensive designs created to balance maximizing energy while minimizing heat dissipation for a specific model, and studied by the company's own expert teams to specifically fit in the phone they're added in.

Random third party from lowest price manufacturers are usually not.

In fact, as you've shown, even first-party batteries can be dangerous if rushed -- like in the Samsung case you noted.

I don't think it's FUD. I didn't do extensive research, but I quickly googled phones with replaceable batteries and found these two from LG:

LG V20 - 5.7” display, 3200mAh battery, 174g LG V10 - 5.7” display, 3000mAh battery, 192g

And here's a phone from the same manufacturer with a soldered in battery:

LG V30 - 6” display, 3300mAh battery, 159g

That's a bigger display, a bigger battery and an overall lighter weight.

It's easy for me to believe that manufacturers are soldering in batteries to deliver thinner, lighter phones since that's what they claim, and that's what they seem to deliver. But I'm happy to look at your numbers.

FYI, the display is bigger, but the phone is actually smaller due to the "bezelless" design of the LG V30.

The difference in weight is mostly due to the reduced body size, so less materials used.

A thinner phone also generally weighs less due to less material.

The combination of soldered battery (so thinner phone) and "bezelless" design could explain a large part of the difference in weight due to less materials used.

[LG V20 specs] https://www.gsmarena.com/lg_v20-8238.php

[LG V30 specs] https://www.gsmarena.com/lg_v30-8712.php

Yes there is a reason. It is called safety. There is a big difference in making a battery in phone safe to handle and separate stand-alone battery safe to handle. This includes things like puncture resistance, heat dissipation, vibration and shock test. This results in thicker/heavier housings for the replaceable batteries.

"Safe to handle" here does not mean "looks good to me," but tested against mandatory standards.

Battery acid isn't safe to handle, so it's shipped in a container. Same for a battery, if it were unsafe external to the device then there could just be a shipping caddy - remove the battery from caddy, place old battery in caddy and take for recycling. That would probably be safer than the current situation.