Question Phase change to extend battery life ?

[FreeBee101]

I don't know if this is done or not, but could phase change packets be used in laptops to generate electricity with use and recharge the battery on use like a hybrid electric car does? Does anyone do this now or would it be possible?

 

[Aeacus]

could phase change packets be used in laptops to generate electricity with use

I don't quite follow what you're asking.

Phase change material (PCM) is used as a part of thermal management system in car batteries. It does not generate nor store electricity. It instead can store heat or cold, to keep the battery at nominal operating temperature, especially when battery is discharged and recharged.

like a hybrid electric car does

HEV generates electricity solely due to gasoline engine it has. Whereby gasoline engine then rotates the shaft inside the electric motor to generate electricity and some of it is stored in a battery. For a HEV, it's driving range using solely electricity is very small. 20km or so (due to small battery). Without gasoline engine, HEV won't be drive-able (some HEVs use electricity stored in battery to reduce load on gasoline engine, rather than being alternative mode of power to turn the wheels).

 

[FreeBee101]

No, I mean could it be used to generate from heat.

The first question is can you safely just throw in a cheap 5 collar PCM packet into a laptop or a computer and use it to cool the computer better? Or does it not work that simply to get the heat into the packet. Would it help with a room that is too warm for example.

 

[Aeacus]

The first question is can you safely just throw in a cheap 5 collar PCM packet into a laptop or a computer and use it to cool the computer better?

PCM for laptop (chips) use is essentially a form of thermal pad.

Here's one such PCM pad for chips,
specs: https://www.thermal-grizzly.com/en/phasesheet-ptm/s-tg-ps-50-40

If used for chips cooling, it essentially acts as heat transfer median, from the chip to the cold plate. Since the pad itself is so thin, it doesn't have much heat storing capacity, hence why it is used to transfer heat forward.


In BEV battery systems, PCM is used as median to spread out the heat of individual cells.

Direct link if image doesn't load: https://ikrorwxhijqili5q.ldycdn.com/cloud/piBpmKmiRljSqkoopolil/PCM.png

On the left side, there are bare battery cells, which, without better cooling than ambient air, would cook themselves.

In the middle, battery cells are surrounded by PCM, which helps to spread the heat around. Better than ambient air cooling but still not the best for the cells in the middle of the pack.

On the right side, is CPLS, which is Coupled PCM-Liquid cooling thermal management System. It is a form of active cooling for battery cells, to keep individual cells (even those at the middle of the pack) at nominal operating temperature without overheating.

The PCM is used as the main heat dissipation material to keep the battery at the optimum operating temperature during discharging, and the liquid cooling acts as the role of recovering the latent heat of the PCM timely during charging.

What you are asking, is taking the heat inside the PCM and somehow, magically, turn it into electricity.

There is thermoelectric generator (TEG) out there, that uses thermoelectric material to turn heat into electricity. But at current date, those are used in power plants and some BEVs.
Further reading: https://en.wikipedia.org/wiki/Thermoelectric_generator

But with an efficiency of 5%-8%, bulky size and the cost of it, it isn't feasible to make one for consumer electronics.

Or does it not work that simply to get the heat into the packet. Would it help with a room that is too warm for example.

You can get the heat into PCM just fine. But the question is, how you can get the heat out from PCM, into TEG, to turn heat into electricity. Better question is to get a TEG that is small enough to fit inside the laptop, doesn't cost a fortune + then some, and is efficient enough in a reasonable time frame, to justify it's manufacturing cost.

What you are seeking, does not exist as of now (at least in the small size, high enough efficiency and low cost to make it worthwhile). Maybe in 50 years time or so, when science advances enough, there are cheap, small and efficient TEGs for consumer electronics.
But by that time, component efficiency could be that good, that there's little, if any, excess heat. Making usage of TEGs (and research into them) pointless.