Hello, This is an Lto cell. Uh, Lithium Titanium Oxide, otherwise known as Lithium Titanate. So this is a Yinong Uh 66168. It's a 40 amp hour cell and the nominal voltage is 2.3 volts.

I Think you can charge these up to about 2.8 and discharge them down to 1.5 volts. So how does an Lto cell differ from Nmc or Lfp? Well, the first thing you notice is that it has this lower Uh voltage nominal voltage 2.3 On the Lto cell, Lfp is 3.2 Vols and Nmc is typically 3.7 Vols. Now, that, of course, means that these cells have a lower Uh volumetric energy density and also a lower gravimetric energy density. So that's a weight-based energy density.

Uh. But they have so many other advantages that Lto cells are definitely worth taking a look at. So the first of those advantages is power density or C rate. So these are rated at 40 amp hours, but they're rated for pulse charge and discharge rates of 10 C So that's 400 amps.

And of course for that, you need a very low internal resistance. So I'm going to attempt to measure the internal resistance of this cell now. I'm not sure how successful this is going to be because this battery charger only measures down to Uh 1 milliohm and uh, these cells are rated for a fraction of a milliohm internal resistance. But let's give it a go and we have 2.25 Vols Uh 0 milliohms.

So yes, it's so low the internal resistance that this measuring device just shows it as zero. Interesting Now I Should say at this stage, Um, that these cells have been very kindly supplied to me by Hakari Battery.com They sent me three of these cells. Uh, this is an A graded cell. Uh, they also sent me this BG graded cell and this B minus graded cell and I'll talk about the grad now.

Hakari used a much more precise uh internal resistance tester than I have and they measured these at Uh 32 milliohms for the A grade uh, the BG grade is41 and the B minus grade. This one is Uh 78. so they're all below 1 milliohm. Let's do some rough calculations.

Let's call these 1 m I uh at 100 amps. So we're looking at I^ 2 R 100 amps would be 10,000 time 10us 3. So that's 10 watts. Uh, at 200 amps current, we're looking at 40 Watts That is the internal heating effect of having an internal resistance of 1 milliohm.

Of course, if it's less than 1 M like the A graded cells, then these numbers of course will be smaller. 300 amps will give you9 0 wats of internal heating Now Haki battery very kindly gave me another Lto cell. It's this one. It's a 40 amp power.

Uh, they say 2.4 Vols So 96 wat hours. Um, this one has a slightly smaller diameter I think it's 60 mm whereas these are 66. So what are the other advantages of Lto cells apart from this? Uh, very very high current, this high power density? Well, there's temperature range. Uh, these cells can be charged and discharged at very low temperatures and quite high temperatures.

Uh, we're talking down to something likeus 40 C The numbers vary depending on where you look. Um, I think uh, Yinlong say minus 50 C and up to 65 C So you can charge the well below 0 C which of course you can't really do with Lfp. Uh, the next thing is cycle life. I've seen numbers ranging from 20,000 Cycles to 30,000 Cycles Uh, This, of course is massively higher than Nmc cells, and even an order of magnitude higher than Lfp and calendar aging 20 years.

I've also seen 30 30 years proposed for these cells. Safety: Uh, There's a video on the Yinong website which shows these things: uh, being guillotined in half angle ground, drilled through with a drill, uh, squashed, dropped, and all manner of other things. And there's no fire, no explosion. So let's take a look at.

uh, this company. Yinong. Well, they're now part of Gree Alter Nano New energy you can see here previously Yinlong Energy and I'm on the website Yin long. Energy.

Um, so you can see that they make uh, Lto batteries, commercial electric vehicles, and electric Chargers Well, those electric vehicles if we click the electric vehicles link are electric buses. So here we have a 12 M Electric Transit bus And there's some data down the bottom of this page which shows that you can get it in two types: um, Lto, Lithium Titanate, or Lfp. And what's interesting is that the Lto bus has a proximately 100 kwatt hours of energy storage. The Lfp has about 300 kwatt hours.

Now, if you remember the Uh Hakari Lto cell said 96 W hourss let's called, call it 100 wat hours. Well, the bus has 100 kilowatt hours. so the bus will have something like a thousand of those Lto cells. Now if you go to the Wikipedia article on Electric Bus, there's an entry here that says as of 2017, 99% of All Battery electric buses in the world have been deployed in mainland China with more than 421,000 buses.

So if these SE were all Lto buses at this time, they may not have been. But if they were, then 421,000 buses is 421 million Lto cells. And you can see on these cells um, that the dates are all around that time 2017, this is 2016, this is 2018, and this is 2019. Um, so electric buses really were huge in China, but not really anywhere else at this sort of period.

And that leads me to believe that there must be a lot of these cells kicking around somewhere or other, and a lot of them are probably coming out of these electric buses now. It also says by 2021, and of course we're now in 2024, Um, Europe had reached 8,500 buses. So electric buses are growing now worldwide. Um, but even in 2021, the Uh China share of electric Bu is remainder 98% So going back to Yin long.

Energy's website you can see under Battery tech that they're saying the Lto battery life cycle is 10 years in a vehicle plus an additional 20 years as energy storage outside of the vehicle giving a total lifespan of 30 years. They also go through some of the advantages of Uh Lithium Titanate, Titanate Oxide. Interesting I think titanium oxide or just titanate. Um, fast charging.

So a theoretical Uh charge in 6 minutes, but the electric vehicles were being charged in 20 minutes. Uh, very wide temperature range from -40 to plus 60 C very long lifespan 30,000 full depth of discharge Cycles Uh ensuring a remarkable lifespan of 30 years High charge and discharge capabilities, pulse currents of 400 amps for these 40 amp cells and safety. So Uh I'll put a link to a video uh where you can see these things being chopped up, drilled, angle, ground, and all that sort of stuff. So where are these Lto cells being used? Uh now.

Well, there's one area where these Uh have found a particular Niche and that is in Car Audio Systems. Now when I say Car Audio I'm talking about extreme high power car audio. Um where 400 amps at 12 volts or 500 amps at 12 volts gives you uh 6 kilow. So a typical installation would have six of these in series to give you.

uh well, a high version of 12 Vols a a battery that can be paralleled up with a lead acid battery and connected to a car alternator. Yes, six kilow of audio. It's not something I'd want in my car, but some people are very enthusiastic about extreme base. And here's the sort of final advantage of Lto cells.

It's quite subtle, but if you take four Lfp cells like these uh, 3.2 volt nominal 105 amp power cells, and you put them in series, the maximum vol voltage per cell 3.65 Vols gives you 7.3 for two. So 14.6 Volts for the 12vt pack. Now, if you've got a car alternator, um, putting out about 14.6 volts, you're right at the very top of Lfp's voltage span. And if you've got any mismatch in terms of cell balancing, then it's likely you'll push one of the cells above its maximum 3.65 volt.

Vol Now, if you put six of these Lto cells in series, that's 6 * 2.3 nominal, So that's 13.8 volts. But the maximum voltage that these six cells in series can take is 16.8 Well, that's way above. well, a little bit above. uh, the maximum for lead acid and any alternator you're likely to come across, and the minimum voltage that these cells can go down to is 9ine volts.

So it's very easy to put an put an Lto 6s pack in series with lead acid, charge it with a vehicle alternator, and you easily cover the range of voltages that the Les acid battery uh can handle. and you probably don't need a BMS you would need a balancer to keep the six Uh cells balanced, but uh yeah, you could get away with no BMS cuz you're never going to be likely to push any one cell over its 2.8 Vol maximum. So what am I going to do next with these cells? Well, I've been making up uh cables for my charger discharger. so I'm going to charge these cells to their maximum voltage.

Do a discharge. Uh. check the curve shape. Also, uh, check the capacity of these cells, discharge them right down to their minimum voltage.

uh, and test these three cells not for internal resistance because I don't really have the equipment, but for that. but I can test their capacity. and so that's a quick introduction to Lithium titanate cells. and I've already started charging this one and then I'll do a discharge and I'll come back with the results in another video.

But for this video, that's it. Cheerio!.