NCM 90: successor of NCM 811 battery cells

Yoon Ye-seon, head of SK Innovation's Battery Business Division

Developing a battery chemistry is always an exercise that requires making concessions. There isn’t a battery chemistry that is the best in every field, to have a well balanced battery we have to make compromises regarding energy density, power density, safety, cycle life and cost.

In this long article we’ll see where the battery technology is going with the focus on the development of NCM cathodes. I’ll leave anodes and electrolytes to another time.

 

Let’s start by comparing some popular battery chemistries for electric vehicles. Rates vary from 1 (worst) to 5 (best).

 

Anodes

Lithium Titanate Oxide (LTO)

  • Energy density: (★) 1/5
  • Power density: (★★★★★) 5/5
  • Cycle life: (★★★★★) 5/5
  • Safety: (★★★★★) 5/5
  • Cost: (★) 1/5

 

Cathodes

Lithium Ferro Phosphate (LFP)

  • Energy density: (★★) 2/5
  • Power density: (★★★★) 4/5
  • Cycle life: (★★★★) 4/5
  • Safety: (★★★★★) 5/5
  • Cost: (★★★★) 4/5

 

Lithium Nickel Cobalt Aluminium (NCA)

  • Energy density: (★★★★★) 5/5
  • Power density: (★★★) 3/5
  • Cycle life: (★★★) 3/5
  • Safety: (★★) 2/5
  • Cost: (★★★★★) 5/5

 

Lithium Nickel Cobalt Manganese (NCM 333 or 111)

  • Energy density: (★★★) 3/5
  • Power density: (★★★) 3/5
  • Cycle life: (★★★★) 4/5
  • Safety: (★★★★) 4/5
  • Cost: (★★★) 3/5

 

Lithium Nickel Cobalt Manganese (NCM 523)

  • Energy density: (★★★★) 4/5
  • Power density: (★★★) 3/5
  • Cycle life: (★★★) 3/5
  • Safety: (★★★) 3/5
  • Cost: (★★★★) 4/5

 

Lithium Nickel Cobalt Manganese (NCM 622)

  • Energy density: (★★★★) 4/5
  • Power density: (★★★) 3/5
  • Cycle life: (★★★) 3/5
  • Safety: (★★★) 3/5
  • Cost: (★★★★) 4/5

 

Lithium Nickel Cobalt Manganese (NCM 811)

  • Energy density: (★★★★★) 5/5
  • Power density: (★★) 2/5
  • Cycle life: (★★) 2/5
  • Safety: (★★) 2/5
  • Cost: (★★★★) 5/5

 

The LTO and LFP chemistries are only used when really fast charging (5-10 C) is required, for example in electric buses. While NCA is used by Tesla, almost every automaker uses batteries with NCM cathodes.

It’s widely known that the main obstacles for the adoption of electric cars are price and range. Therefore, recent improvements in NCM cathodes have been focused on increasing the energy density and reducing costs, at the expense of reducing power density, cycle life and safety. However, higher battery capacities reduce the problem of lower power density and poor cycle life. As for less safe battery cells, they require more protecting BMS (Battery Management System) and TMS (Thermal Management System) but aren’t really dangerous.

The general formula used to decrease cost and at the same time increase energy density of NCM battery cells has been to reduce the cobalt content of the cathode, by replacing it with more nickel. Adding silicon to graphite anodes also helps to increase the energy density, at the expense of reducing cycle life. Remember, it’s always a compromise…

This year marks the introduction of NCM 811 batteries to mass-production electric cars. The Chinese company CATL won the race and was the first manufacturer to put NCM 811 battery cells into a mass-production electric car that is already being delivered to customers – the NIO ES6. Nonetheless, others are following.

BYD is another Chinese battery cell maker that announced NCM 811 batteries for this year. While Envision AESC aims to start producing NCM 811 battery cells in 2020.

As for Korean battery cell makers they have been postponing what they promised before everyone else. SK Innovation now expects to introduce its own NCM 811 battery cells for EVs on full-scale early next year, while LG Chem will bet on NCM 712 cathodes for pouch cells. Samsung SDI is far behind and only expects to start producing NCM 811 battery cells in 2021.

It’s clear that the NCM 811 battery cells are the present and the near future for electric vehicles. They have great energy density and low cost, allowing longer range and cheaper electric cars. However, they already have a successor in the making…

SK Innovation announced that its NCM 811 battery cells – to arrive early next year on full-scale – give 600 km (372 miles) range to electric cars, but it’s in 2022 when range won’t be a problem anymore thanks to the introduction of NCM 90 (NCM 9.5.5) battery cells.

As you already guessed from the designation the NCM 90 (NCM 9.5.5) cathodes are made of 90 % nickel, 5 % cobalt and 5 % manganese. They further reduce the need of cobalt, which is scarse and expensive.

Now let’s look behind the hype and see where this battery technology development is currently at.

 

Cycling performance of NCM cathodes using Li metal anode

 

The charts above show us cycle life of different NCM cathodes at very high charging voltages. Don’t be scared by the apparent high degradation of the cells. It’s expected for such high charging voltages, the kind of voltages that we usually see on smartphone batteries.

Fortunately electric cars have their battery cells better protected and limited to lower charging voltages. For example the battery cells of the Nissan LEAF are limited to a max charging voltage of 4,2 V. Other electric cars have even lower limits to reduce battery degradation.

Now back to the charts.

The authors mention that “the NCM-622 (4.5 V) and NCM-811 (4.3 V) exhibited a similar initial discharge capacity of 200 mAh g-1 at 0.5 C with a capacity retention of 93% after 100 cycles.” Moreover, the NCM 622 cathode had higher structural stability.

However, even if the NCM 622 cathode is safer and when limited to 4,5 V has a cycle life and capacity similar to the NCM 811 cathode when limited to 4,3 V, it’s a no brainer to adopt the latter for electric cars due to cost reduction by requiring less cobalt. Remember, there are always compromises in battery technology and now the focus is to reduce the costs to allow the massification of electric cars.

Now regarding the NCM 90 cathode things are looking good, but it might not be ready to replace NCM 811 cathode just yet.

The NCM 90 cathode when cycled between 2,7 and 4,3 V at 0,5 C retains 90 % of its initial battery capacity after 100 cycles. Therefore, a new electric car with a 600 km range would have a 540 km range after 57.000 km [(600 + 540) / 2 x 100)] in these conditions. The good news is that no electric car battery is cycled in these extreme conditions. They are far better protected.

I would like to see how the NCM 90 cathode behaves when cycled between 2,8 and 4,1 V, it’s reasonable to expect that the cycle life is much better than only 90 % capacity retention after 100 cycles. It has to be good enough to allow a standard battery warranty, which for most EVs guarantees a minimum capacity of 70 % for eight years or 160.000 km (100.000 miles).

Until we have completely cobalt-free batteries, NCM 90 cathodes are a required step forward to allow the massification of electric cars.

Anyway, SK Innovation was the first battery cell maker to announce the NCM 90 battery cells, but I doubt it’ll be the first to produce them. I think that it’ll probably be either CATL or BYD.

 

This article was only possible thanks to Sci-Hub. “Sci-Hub is a project to make knowledge free” that gives everybody access to research articles that are usually trapped behind paywalls. Sci-Hub is the democratization of Science.

Thanks Emanuele for the heads up.

 

 

More info:

https://sci-hub.se/https://pubs.rsc.org/en/content/articlelanding/2019/ta/c8ta10438g

http://english.etnews.com/20190617200001

This Post Has 27 Comments

  1. When reading about batterys a few years ago, I came across a new exciting development that was supposed to bring many benefits in terms of capacity, longevity and price: graphene. Since then, near to nothing has come up. Can this be the promised future we’re hoping for batterys, but still in development and unable to be commercialized just yet?

      1. There was a time when we were told that graphene would replace whatever it is they put inside Big Macs. Nothing came out of it. In fact, is there any use at all for the magical unicornian graphene? I wonder

      2. I wonder if there is a site that lists all battery chemistries, and their progress towards being available?

  2. NCM 523 seems the best of all….

    1. Yes, NCM 523 and NCM 622 seem to be the most balanced cathodes. However, when the focus is to get longer range and cheaper electric cars, getting more energy density and lower cost compensates the reduction of cycle life, safety and power density.

  3. “I’ll leave anodes (…) to another time.”
    And yet, you begin with LTO which is exactly ANODE’s abbreviation.
    Plus what is the reference for the Cost scale? 5 stars is good or bad?

    1. Ok, I’ll make it clearer. I just meant that the article focus is on the development made in cathodes, in this case NCM cathodes. Rates vary from 1 (worst) to 5 (best). 5 in cost means cheaper.

      You can find a similar rating on this website: https://batteryuniversity.com/learn/article/types_of_lithium_ion

      But I think that the rates I present are more updated with the recent developments made in different chemistries.

      Thanks for the suggestions.

  4. I choose for NCM 111 in my BMW i3s, for the safety and cycle life.

    1. Just for reference.

      BMW i3 (60 Ah): NCM/LMO blend (no source, but my guess)
      BMW i3 (94 Ah): NCM 333/111
      BMW i3 (120 Ah): NCM 622

      1. I own a 94 Ah i3S rex with NCM 111, my second i3 rex and this one will stay.

      2. That battery will last forever.

      3. What about Samsung SDI 37 Ah PHEV2 cells used in the Volkswagen e-Golf 2017 battery? Do you know what chemistry do they use?

      4. I don’t know for sure the chemistry used in Samsung SDI 37 Ah PHEV2 cells, my guess is NCM 333.

  5. 1. Then you are badly misinformed – NCM 811 is very expensive due to high additional surface processing costs. Otherwise it is going to crack and break before used.
    2. BU is no better for me than any other random source – they are not cross-checking their data, nor correcting them if pointed directly on the mistake. However, they clearly mentioning LTO being anode paired with NMC or LMO, which was omitted in the original revision of your post. (Plus LTO is also used with LFP where the energy density is not that important).
    3. No 333 or 523 or 622 or 811 is equal between material suppliers and cell producers. It is like comparing tires just based on their dimensions. What you show here is simple “theoretical” and “marketing” subjective summary. Nevertheless, good to know someones own point.
    4. No need. I rarely comment technical posts as I know how big PitA I can be. Just having worse day and couldn’t stop myself.

    1. I welcome your comment but in part disagree.

      The more complex production of NCM 811 battery cells can be automatized, therefore with mass production costs will be much lower. With other less energy dense chemistries you still need more expensive raw materials (namely cobalt) and automation won’t solve this problem.

      For example, Tesla battery packs seems to be a PITA to assemble. Many small cylindrical cells require more work to assemble than large prismatic or pouch cells. However, when Tesla automatized this process the cost dropped significantly and despite being a complex battery pack, it has the cheapest cost per kWh mostly because of the low use of cobalt.

      Of course that the ratings of the battery chemistries are just an approximation. We all remember that LiFePO4 battery cells from A123 were much better than others at the time, despite using the same chemistry.
      When comparing different commercial battery cells with the same chemistry, IMO the best are usually from Samsung SDI. They are slow to adopt new technology and prefer to improve mainstream chemistries instead.

      I always welcome constructive criticism like yours, feel free to correct anything that I write here. I hope your day gets better.

  6. Maybe, you addressed this in some other article. Is there any difference in degradation by cycling the battery more often between 3-4 V, as compared to a lower number of cycling between 2.8-4.1 V?

  7. What do you think of solid-state batteries? Do you think they’ll be used in the near future?

    1. I don’t have enough information to have an opinion about it right now. I plan to do some extensive research on Sci-Hub for a future article on the subject.

  8. So, to dumb this down to the max, trend is to increase Nickel content and reduce manganese and cobalt, as the latter are more expensive. While LFP will stay on as battery of choice for buses. Is that right?

  9. Excellent summary of current state of play in cell chemistry.
    Without pushevs I wouldn’t know any of this.
    Thank you Pedro, I always look forward to your posts.

  10. Hello Pedro,
    I am a bit uneasy with Your chemistries ratings i.e. NCA is rated better or the same as NCM 111 in all respects, which begs the question why produce NCM 111 at all. Only explanation would be that some manufacturers do not have the technology, but I don’t really think that is the case, and NCM 111 actually is better in some areas.

    Considering AESC is going to introduce NCM111 next year, are we going to see next update of LEAF sometimes in 2021?
    Thanks for the post. It is always a pleasure to read something this informative.

    1. Hi.
      I guess you mean NCM 811, not NCM 333/111, right? Remember that NCA has been constantly improved by Panasonic to meet Tesla’s requirements. Unlike other automakers, that tell battery cell makers to focus on cost and energy density, Tesla also need a good power density, to allow great charging – at Superchargers – and good discharging rates for amazing acceleration.

      Moreover, Tesla batteries require decent cycle life, since they need to endure tough conditions (high charge and discharge rates) and still offer a good warranty to customers.

  11. It should be interesting to see how battery chemistry criteria change in favor of charge rate, when every former gas station ends up with a bank of 350+kW chargers that would recharge the avg US daily drive in under 2 minutes.

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