I don't think this is where peak battery tech ends up. At current capacities, batteries are becoming genuinely dangerous, and faster charging only amplifies the risk. Charging high-capacity cells outside a temperature-controlled charger is risky, and even reputable chargers shouldn't be left unattended — many workplaces ban it outright (it only takes one fire to make that policy). Phone batteries are the worst of it: highest power density, fastest charging, odd geometry, and tight space constraints. Manufacturers shrink the phone by offloading temperature monitoring and heat dissipation onto the phone's own electronics and housing — so replaceable, externally rechargeable batteries are tricky to design. IMO, swappable batteries were a feature because batteries used to suck. In less volume-constrained devices like cameras, swappable batteries still work — but you're trading single-charge runtime for that convenience.
This last point is actually a real killer, an easily swappable battery in a phone probably sacrifices >10% "maximum" capacity in lost space. e.g a phone with a glued battery can have 5000mAh but the same phone with a more durable battery connector can only be 4500mAh.
The main thing that makes all this hard to do is the form factor.
Give these phone batteries a standard geometry and interface and pretty much all these problems immediately go away. 3 prongs on the battery (ground, positive, data). A standard protocol so the battery can communicate things like SOC or acceptable charge rate with the charger. And viola, you are off to the races.
Yes, this will mean manufacturers will have a hard limit on how thin they can make their phones and a constraint on what designs they can employ.
Ultimately the main benefit obtained from not allowing battery replacement, is an increase in sales of newer models.
While your reasoning has _some_ merit, it reads as an apologia for the status quo .. rather than an example of why we should prevent easy battery replacement.
> e.g a phone with a glued battery can have 5000mAh but the same phone with a more durable battery connector can only be 4500mAh.
alternatively, i can trade more bulk for more battery. if its got a connector, why cant i put a bigger batter in the slot that sticks out?
Slop
We don't need fast charging. Phones will be left on wireless charging surfaces, which will eventually be ubiquitous. Everyone hates usb-c plug in. Just leave it on a surface, pick it whenever you want.
We don't need to fast charge anything, phones or EVs. Slow charging preserves battery life and smart charging will charge whenever it is cheapest.
It's the exact same as with EVs.
We COULD have an EV with a 200kWh battery that can go 1000km++ on a charge in -30C weather. But nobody really needs that beyond a few outliers.
What we NEED is ubiquitous and easy charging.
Going for a burger, it'll take 20 minutes for you to order, eat and walk out. On a 300kW charger in the parking lot you can in theory get up to 100kWh charged. Or less with a slower one. Even plugging in to a 50kW charger for 20 minutes is enough.
Same with shopping etc, giving "everyone" a 2kW charger in a parking lot is table stakes in 2026.
And with phones: just have the possilibity of charging everywhere. I have 13€ Ikea Qi2 ("Magsafe") compatible chargers[0] everywhere in the house. Anyone can just slap their phone on one and it'll charge a bit.
There's no reason why we can't have more of those in public - we did try when wireless charging first appeared, but it was a whole chicken and egg thing. Nobody had phones that supported it and finding the exact 1x1cm spot where the phone charges was a pain. Qi2 with the alignment magnets takes that problem away completely.
[0] https://www.ikea.com/us/en/p/vaestmaerke-wireless-charging-s...