What new battery technology are you keeping an eye on?

[DavidH]

I know there's a big drive to find better batteries that can be competitive price wise. What technologies are you all keeping your eyes on? Any that are looking very promising for solar installations? Thought this could be an interesting topic to delve into.

[Mike90250]

Watching them all.

[khanh dam]

https://www.bloomberg.com/news/features/2019-08-03/a-deluge-of-batteries-is-about-to-rewire-the-power-grid

there are some interesting youtube videos on using lithium batteries from Nissan leaf and other electric cars. if you have a local copart.com auction site, you can get the batteries cheaply if you put in the work to extract the from the car, which is no easy task given their weight and location. if you buy the entire battey off ebay they are around $3500

Battery Specs

Type Laminated lithium-ion battery

Voltage 403.2V , page 9

Nominal voltage 360V

Total capacity 24 kWh

Power output Over 90 kW

Energy density 140 Wh/kg

Power density 2.5 kW/kg

Dimensions 61.8 x 46.8 x 10.4 in. (1570.5 x 1188 x 264.9 mm)

648 lbs

Number of modules 48, each with four cells (total 192 cells)

Battery pack contents:

[Ampster]

Some people consider LFP new technology even though it has been around 20 years. That is the one I am keeping an eye on with regard to lower prices. It is also the safest.

I suspect the big increases in energy density will be made in the more volatile chemistries used in EVs (NCA etc.). I have two EVs and in 3 1/2 years the improvement in energy and power density has largely been subtle changes in the electrolyte. Unrelated to the topic of this thread, improvements in motor efficiency have also had an impact in motive applications.

Large grid scale storage is using the more volatile NCA chemistry but with an electrolyte the favors energy density over power density. With that scale efficient cooling and battery management strategies have reduced the risk. Tesla has sold over 50,000 Powerwalls which use passive cooling. Unfortunately that scale has not resulted in any price decreases. Some of that is probably because of the installation expense related to interfacing with each unique electrical infrastructure in the home.

[Ampster]

there are some interesting youtube videos on using lithium batteries from Nissan leaf and other electric cars. if you have a local copart.com auction site, you can get the batteries cheaply if you put in the work to extract the from the car, which is no easy task given their weight and location. if you buy the entire battey off ebay they are around $3500..........

I am currently using 54 Nissan Leaf modules. 40 of those came out of one 48 module pack that I purchased for $1500 3 years ago. They are easy to configure into a 48 or 56 volt packs. While my average cost is around $100 per kWhr they have degraded somewhat and are useful for back up and some load shifting. I would not recommend them for serious off grid use. They require a lot of monitoring and some shifting of modules to keep the pack more balanced near the knees. Your mileage may vary.

[DavidH]

Yeah I'm hoping LiFePO4 battery prices continue to decrease in the next few years. I've been reading that there's a lot of research going on to find alternatives to lithium for use in batteries. Sodium seemed to be one they were interested in. I did find something about salt water batteries as a substitute for lead acid batteries in home or grid use, but I understand that the company went under for some reason.

[Ampster]

Yeah I'm hoping LiFePO4 battery prices continue to decrease in the next few years. I've been reading that there's a lot of research going on to find alternatives to lithium for use in batteries.

Here is Bloomberg's take: (October 2018)

https://www.bloomberg.com/quicktake/batteries

Sodium seemed to be one they were interested in. I did find something about salt water batteries as a substitute for lead acid batteries in home or grid use, but I understand that the company went under for some reason.

It seems to me that many those new battery technologies go under because they don't scale up efficiently. There has to be plenty of venture capital will to invest in truly viable technology.

[Ampster]

Here is an interesting article about Jeff Dahn's conclusions:

https://cleantechnica.com/2019/08/09/tesla-battery-guru-jeff-dahn-claims-new-lithium-ion-cell-outperforms-solid-state-batteries/?utm_source=marfeelpush

[DavidH]

That's interesting about solid state batteries. What's the advantage of them? Is it a safety thing? I guess at the end of the day whether it's commercially viable and worth building new factories to produce them is what it all boils down to.

[Markyrocks69]

I am currently using 54 Nissan Leaf modules. 40 of those came out of one 48 module pack that I purchased for $1500 3 years ago. They are easy to configure into a 48 or 56 volt packs. While my average cost is around $100 per kWhr they have degraded somewhat and are useful for back up and some load shifting. I would not recommend them for serious off grid use. They require a lot of monitoring and some shifting of modules to keep the pack more balanced near the knees. Your mileage may vary.

So are you not using bms? What kinda % of charge and discharge are you using? With lithium ion batteries from what I've seen keeping the batteries between 20-80% should give 1500+ cycles, if you're cycling once a day that should be around 5 years. Even if you went like 80-30 could stretch that even longer. What would you reccomend otherwise? How do these compare to lead acid batteries? From what I'm seeing in my battery education lead acid would be lucky to get half as many cycles in similar conditions. The only other thing to consider is how long were these leaf batteries in service in the vehicle they were in? If they had high mileage on them to begin with one could assume that they got thoroughly used b4 you ended up with them and theres no telling how they were treated during the first part of their life.

I'm also thinking if batteries were in a car that's not very old with high miles chances are whoever owned them were probably charging to 100% often and deep discharging regularly as well. The inverse could also be said for an older car with low miles. Meaning probably never charged to 100 (unless the owner was just an idiot) and probably rarely deeply discharged.

[BoloMKXXVIII]

Many millions of dollars are being poured into research for better batteries. Companies know whoever finds the right mix of price, performance, scalability, and eco-friendliness will make incredible amounts of money. Any small company that comes up with a 'better mouse trap" will be bought out or litigated out of existence. Look for one of the larger companies to bring the next generation of batteries to market. The trick is to identify the real deal from the marketing hype. Buying the batteries isn't the big deal, buying stock is.

[Ampster]

So are you not using bms? What kinda % of charge and discharge are you using? With lithium ion batteries from what I've seen keeping the batteries between 20-80% should give 1500+ cycles, if you're cycling once a day that should be around 5 years. Even if you went like 80-30 could stretch that even longer. What would you reccomend otherwise?

I am using an Orion Jr BMS. I am going to 4.05v which I think is about 85%. I rarely discharge below 3.95v. Other alternatives I have looked at are Tesla Modules and LFP from China. There are more issues to deal with using Tesla modules if you try to parallel them.

How do these compare to lead acid batteries? From what I'm seeing in my battery education lead acid would be lucky to get half as many cycles in similar conditions. The only other thing to consider is how long were these leaf batteries in service in the vehicle they were in? If they had high mileage on them to begin with one could assume that they got thoroughly used b4 you ended up with them and theres no telling how they were treated during the first part of their life.

I'm also thinking if batteries were in a car that's not very old with high miles chances are whoever owned them were probably charging to 100% often and deep discharging regularly as well. The inverse could also be said for an older car with low miles. Meaning probably never charged to 100 (unless the owner was just an idiot) and probably rarely deeply discharged.

I am biased toward Lithium, and just prefer them to Lead Acid. They can be paralleled so it is easier to incrementally add capacity. It sounds like you understand the risks of dealing with used batteries. You are also correct about Leaf batteries and the risk is even greater because they have no cooling. I did lose 10 of them but that was my mistake leaving them in a GEM car with a vampire drain that caused them to drain completely and swell. To their credit I have seen Lead Acid or AGM batteries come back from a full discharge. I am sure they lost some capacity but they were usable.

[rebar]

Remember eestor? I think they even fooled the military

https://www.google.com/search?client...4dUDCAo&uact=5

[PNjunction]

Ampster - thanks for the link to Dahn - and I agree with him completely.

Especially about dendrites and the need for solid electrolyte. That would be a home-run with LFP for our purposes. Even existing non-lfp would be a total win.

But as always, many of the battery discoveries are investor-bait, patent-troll warchest material, or ultimately destined for locked-down proprietary batteries and charging infrastructure.

In other words, don't expect any of these discoveries to be seen at your local auto-parts or non-hobbiest battery store.

And, also keep an eye on the entire life-cycle! What good does it do us to have these marvelous new technology batteries if they involve massive toxic wastedumps and illegal child labor?

[solarix]

I'm watching a potential real game changer called the Liquid Metal Battery. Invented 10 years ago by MIT chemistry prof. Don Sadoway and his company Ambri is currently in beta testing. Check out his TED talk on Youtube. You want a dirt cheap battery? Make it out of dirt.