Search results

Recently I've had to be away from the forum as I've been super busy with work and life, though wanted to check in as I recently visited the first V3 supercharger outside of the US, and this thread was an excellent resource when aiming to understand what speed I should achieve! My achieved...

Potentially - let's see where the technology takes us and what the best engineering solution for the available technology is!

Some interesting trends emerging here. Anybody know if this TeslaFi data can be exported for us to start building up a database to do some analysis?

Yes - to prevent lithium plating. You're building more and more lithium ions at the surface of a graphite anode particle, and building up a big difference in concentrations of lithium particles at the surface in comparison to the core of the particle. . If the rate at which the lithium ions...

The magnitude of the impact made by the cathode phase transition is small in comparison to the SEI on the anode. I've recently taken delivery of my car and plan to charge to 70-90% daily as my needs dictate and not worry about things too much!

What you're currently doing is probably fine. Charging to 75% and staying above 60% to not go through the cathode phase transition *might* be beneficial, though it might not. When we observe degradation of the battery, we are observing the weakest link, which is usually the anode, thus reducing...

For cells with a graphite anode, as per most lithium-ion batteries in the world, the stated charge rate is typically lower than the discharge rate, and this is typically limited by the rate of diffusion in the graphite, (from the core to the surface of a particle or vice versa). As the system is...

Interesting. What's the backstory?

Interesting findings from the early days @darth_vad3r !

Really fantastic post; clearly indicates use of simultaneous extended kalman filters for prediction of individual 'brick SoC', which enables adaptive balancing. I'm more impressed that the BMS algorithms are so drastically revised via an OTA update!

Getting occasionally upto 100% won't be too much of an issue if you don't leave it there for significant periods of time - this about it as the likelyhood of an undesired reaction increasing rather than an irreversible balloon stretch.

@wk057 - An absolutely fantastic post! Sounds like they've implemented extended Kalman filters which have enabled adaptive balancing.

Sounds like you've found the real world limitations of carmakers trying to make things 'simple' for the customer....

Agreed - The power definitely enters the battery, but is highly likely to bypass the cells and directly go to the battery heaters, if indeed battery heaters are present within the pack. Given how well the Tesla pack is designed, I'd be extremely surprised if the energy was transferred via the...

I'm glad you found it useful and clear! I don't think you should worry about occasionally charges to 100%, primarily because 100% indicated SoC isn't 100% real SoC. I can't think of any reason a single charge to 100% would have any significant impact, so I wouldn't worry too much, and...

Looking good! Thinking about a set of those in bronze for my blue M3.

In terms of effect of storage SoC, I'd expect the Panasonic/Tesla cell to have similar behaviour in principle, however I'd expect the capacity loss to be somewhat less. Cells used in the automotive space will typically contain additional electrolyte additives to help provide longer term...

Fantastic info - has anybody done a similar test with a RWD vehicle?

Love this wheel design! Got a side profile shot? What wheel and tyres size?

Great question, which has a short answer and a long answer. The short answer is that the vehicle with the 12V disconnected would degrade less, assuming the SoC does not drop to approximately <1% SoC, and that temperature is broadly the same and not >> 25 deg C. The reason for this is that...

Completely correct that lithium plating would have more of an impact - at these very low temperatures, storage at 90% SoC will have minimal negative impact in terms of electrolyte decomposition and undesired parasitic side reactions, however invoking additional lithium plating could have a...

When cold, the impact of a higher SoC is reduced as electrolyte decomposition and the rate of parasitic side reactions is strongly temperature dependent, and your larger issue becomes lithium plating at high SoC, so I'd suggest simply charging to 90% immediately if that is your desired setpoint...

Good advice - the only addition I'd make is that if we're specifically trying to reduce battery degradation, I'd start charging soon after you park the vehicle following a drive, so that your charge event does not begin after the battery has cooled down to ambient temperature. This is to...

Some really sweet looking rides, thanks for sharing! You've helped me make up my mind - Blue & Gold it is, though I'll probably try go for a wider spoke.

I'm thinking about a set of gold/bronze wheels on my blue M3 - has anybody got a similar setup?

This is a really great, informative thread. A fantastic example of what makes this forum and the Tesla community so awesome!

@jdw gives great advice on this below. Agreed. Once again, @jdw gives great advice on this below. Agreed! Yes, also we're about to see a whole host of additional EV's come onto the market, many of which will do things in very different ways. We will see more low cost vehicles with air...

There are some very thoughtful and interesting questions in this thread! 1. For TMF to be a concern for a typical electrode, the temperature window needs to be over a much higher window than we would normally operate or store a Li-Ion cell, (because of the limited thermal stability window of...

It sounds like your Rav4 regime is good for extending lifetime. Following your return leg, it would reduce degradation if you waited for the battery to cool before plugging in, however given the (relatively) slow rate of charge, and the infrequent journeys, I wouldn't worry about it as the...

It sounds like you're doing a good job of looking after your battery already. Need to read more about what caused the battery fires to comment really, but as far as thermal runaway goes, after the cell is saturated at a particular temperature (around 160 deg C for NCA cells), the cathode will...

As a general rule of thumb, this looks excellent!

Yes, 70% capacity retention for the Model 3. No figure for capacity loss is specified for the Model S and Model X.

For 'normal' degradation, i.e. not a catastrophic event such as lithium plating, the primary degradation mechanism is SEI growth, which consumes cyclable lithium, consumes active material and increases resistance. The summary of what you can best do is in the image in the first post on this...

You're spot on with everything you say - 100% indicated SoC is not 100% absolute SoC, and for short time periods is absolutely fine. An interesting piece of academic literature (can't recall the title but will update the post later with reference) has found, (for particular cells which...

If you don't need 85%, 75% should help when the batter is hot but shouldn't make a huge difference unless you live in a hot climate. If you're not in a hot climate, I'd probably just stick to 85%.

Thanks - I'll definitely put that on my list of future videos!

In relation to your first question, I was thinking about absolute SoC, which as you rightly point out, for Tesla is pretty close to indicated SoC. Absolute max SoC will usually be set by degradation at max indicated SoC in hot climates, whilst minimum absolute SoC will typically be set by power...

When I say thermal stability, I relate this to thermal runaway conditions, thus when I say lower thermal stability, I mean NCA cathodes will enter thermal runaway at a lower temperature, and the rate of heat release will be greater. The charging speed will be primarily impacted by cell design...

Generally high capacity NCA will have both higher energy storage capacity and cycle life stability than NMC 811 right now. This begs the obvious question, why are others looking toward NMC811? There are two main reasons: NCA generates more gas than NMC811 as it degrades - within a...

As the battery has 96 cells in series, I'd expect the resting, open circuit voltage to be: 0% indicated SoC - (really ~3% absolute SoC) - 2.85V * 96 = ~274V 100% indicated SoC - (really ~98% absolute SoC) - 4.15V * 96 = ~399V The minimum voltage can be lower than this when discharging and the...

Thanks, and I hope it can be a useful contribution to the knowledge of the collective. I did a PhD in Electrochemical Engineering, and currently work on battery design so battery topics are my specialist topic.

The vehicle indicated 100% is absolutely not 100% absolute SoC - probably somewhere between 97-98.5%, however a small step down from the max SoC which Tesla shows the customer to be 100% still does make a disproportionately beneficial difference to degradation. As you say, really, all this is...

I'm glad you found my video helpful, and it is nice to see it posted here given the knowledgeable crowd on this forum. Feel free to ask me any specific questions on this topic if not addressed by the video.

Great advice. Also, charging to 97% vs 100% should help reduce degradation somewhat without meaningfully affecting the range available....

Having recently ordered a Model 3, I've been reading this thread and found it to be a great source of information. Having personally done a lot of work on battery degradation analysis, I thought it worth starting to comment rather than just lurking! Sounds like a good battery care routine...

Great to see some of my videos in here. I've recently just created a new, detailed video on battery degradation which it seems fitting to post here.

You're very welcome, thanks for watching!

I've recently finished a three part video series to explain Tesla's battery technology. Tesla's battery technology has undoubtedly revolutionised the automotive industry, and given the historical significance of the battery pack, I thought it worth looking into further. Part 1 explains the...

I'm currently creating a video series to review Tesla's battery technology in detail; this is the second video is all about Tesla's module. I appreciate all the feedback you knowledgeable folk have to offer, and hope you find it interesting. Let me know if you have any questions!

I currently drive a diesel, so really although I'd like the long range, my strongest desire is just to get into an EV for commuting to work asap, though at 55 miles each way I haven't had much choice as sadly I cannot afford a model S.