Keeping this short, LiFePO4 batteries are insanely durable, long lasting, and don’t require most of the minerals that make normal lithium ion batteries difficult. Their only downside is a slightly lower energy density. With that in mind, especially for the upcoming framework 16 and with the ethos of sustainability, why not offer a battery that will last a decade, removing one of the biggest factors that cause people to get rid of tech?
This is exactly it. Framework laptops are already not competitive in terms of battery. They need as much energy density and efficiency as they can get.
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I think there is a better reason and that’s the thermal range which LifePo4 lithium iron phosphate batteries are restricted to. From what I’ve read, LiFePO4 offers a wide optimal temperature range. They can operate well at temperatures between -4°F (-20°C) and 140°F (60°C)…A workload intensive processor or even a laptop sitting in the sun on full brightness and no airflow can surely pass 60c. Unfortunately, their sensitivity to these “extreme” temps will result in extreme loss of performance during the exposure and on the long term, permanent damage is often seen after even just one occurrence. The article I read states:
“Lower Efficiency at Extreme Temperatures: If used in extreme temperatures (below freezing or high heat), the performance of your LFP may begin to degrade. However, this is true for all batteries. They’ll be slower to charge and may have trouble providing their full power when subjected to extreme weather. It’s best to practice battery storage safety to avoid battery hazards for energy storage systems. That means keeping your batteries in a sheltered, dry, cool place like a garage or shed.“
The risk of permanent damage from 140+ heat I think is the most important factor to consider. LiPo batteries are also prone to explode at very high temps too obviously, none of the options are perfect but they seem more resilient at least to the temperature ranges commonly seen in laptop use. Unfortunately LFP just isn’t suitable for a laptop type of application which I suspect is why other manufacturers have not really offered them much either.
Article can be found here:
I’m not an expert, just a guy doing some research and putting my best opinion forward
The battery life problem may make sense in the 13, but I’d think the 16 would be perfect for that.
Even if they didn’t sell them themselves, opening up the battery and charge controllers to programming would be super cool.
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I believe the embedded controller is already open. Communication with the battery and settings for how charging is done is probably handled there.
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Now that my Framework 13 is here, maybe I’ll take a poke at it when I get a chance.
You might want to take a look at how to manually flash the EC with an external programmer, in case things go wrong.
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Official reply from Framework would be the best explanation, but I’d guess that they do not use LiFePO4 batteries because those batteries need different charge circuitry and charge profile. If you try to use the same charger design as with regular Li-ion batteries, the LiFePO4 cells will be damaged and possibly catch fire.
Another reason is that the LiFePO4 batteries have slightly smaller capacity per litre and per kg. However, the currently existing battery doesn’t seem to be as high capacity as would be physically possible so I don’t think that maximum the battery capacity is the reason to avoid LiFePO4 batteries in Framework computers.
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The two main factors (charge current and voltages) are all things controlled in software, so it wouldn’t actually be that hard to use the same physical hardware and just change the software out.
wouldn’t this imply that one needs to do it with the battery out, to be safe, and remember NEVER to change the battery before changing those settings? sounds dangerous 
Not really, it wouldn’t be difficult to have some communication with the EC which would request the appropriate parameters (after all, they’re already doing voltage conversion inside the laptop with constant current functionality, what’s the difference what specific number it is as long as it’s in spec?) Also, all laptop batteries I’m aware of have onboard BMS units which would prevent overcharging/discharging, though ideally those are never used. They work buy just cutting power if something goes wrong, which does work but is obviously not ideal, hence why usually the laptop itself (the EC in the case of a framework) regulates charging on its own in normal service.
Again, putting LiFePO4 in a laptop isn’t something I’ve seen done before and it certainly has its drawbacks (capacity being #1,) but it is likely the most sustainable battery chemistry currently available (within the constraints of a laptop.)
The existing batteries already work similar to that. It’s why Framework needs to update the embedded controller firmware in order to support the new, bigger battery.
The charger (ISL9241) is on the mainboard, and both it and the battery communicate with the EC using I2C/SMBus. The battery presumably contains an EEPROM to identify it, but I don’t know the precise mechanism.
More than that. LFP batteries have worse performance in cold compared to NMC batteries. The most downside other than lower energy density is higher self-discharge rates and flat discharge curve, which makes cell balancing and estimating battery % difficult.
Almost all electronics use lithium-cobalt-oxide (LCO) chemistry, which means that it is very easy and cheap to find manufacturers who will make LCO batteries of any capacity and shape that Framework requests, and charge controllers are easy to find for any configuration. LFP batteries are usually only found in specific form factors which are much larger and thicker than the standard laptop battery, so ordering an LFP battery in a custom form factor would cost a lot.
There would be a noticeable difference in the weight and volume of the battery if Framework used LFP, and one of Framework’s goals is to have thin and stylish laptops which are able to compete with brands like Apple and Thinkpad. LFP has cell energy densities between 100 and 160 Wh/kg, whereas LCO is between 150 and 240 Wh/kg. There are some new LFP variants (LMFP, M3P, etc) batteries coming onto the market with cell energy densities over 200 Wh/kg, but Framework probably doesn’t have access to those.
I love what MNT Reform did, using a battery made of LFP 18650 cells, which the user can easily replace, but that would require a very thick case, which contradicts Framework’s design goals.
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