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Comment by msoad | Hacker News Reader

Article says BYD sells Sodium-Ion cars too. Are those cars super low range with quicker charging times? If they are much cheaper batteries it makes sense for an urban setting to have such cars.

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These are cheap vehicles with modest ranges from brands that aren't known outside China (yet). This is a product category that simply doesn't exist in the US. The lack of range doesn't matter because they are intended for people that don't drive very far. You charge them on slow chargers at night mostly. And if you use a fast charger, the charging goes relatively quickly because these aren't large capacity batteries. Typical size in kwh is around 20-30 kwh only.

China has a large amount of mega cities. Think tens of millions of people. There are a lot of cars driving around in those cities that rarely leave those cities. 200-300km range is all they need and a typical range for a sodium ion battery equipped car. The primary feature of sodium ion in this market is cost per kwh. It keeps the vehicles affordable.

People that need more have access to still cheap BYDs priced priced between 10 and 20K with better ranges. Once you hit 30-40K you are looking at the high end of the market with proper long ranges with proper LFP batteries.

Related, it always seemed weird to me that lithium was leading the way (initially, at least) for grid storage. Lithium won the battery race for mobile applications (e.g. cars, laptops, etc.) where energy density is critical. For grid storage, though, battery weight should hardly be a concern at all. It seemed to be like lithium was ahead solely because there was so much industrial knowledge learned from optimizing for energy density first, but that other battery chemistries had to be better for grid storage once we invested the same economies of scale in them, too.

I totally agree, but I don't find it weird that lithium led for so long.

Sure, in theory, sodium-ion batteries are made of inexpensive materials and are easy to build. You don't need any nickel, copper or cobalt at all and sodium is dirt cheap. But if you look into it, you'll find many thousands of similar examples across countless fields, where something uses advanced materials or parts when there is a simpler and cheaper alternative. If you ever design for manufacturing, you quickly realize that the key is often not simplicity, the key is identifying and using existing high-volume processes. In other words, don't find the cleanest way to solve your problem; instead, kludge together a solution using off-the-shelf solutions already produced at incredible scale.

The problem is that low-cost manufacturing is an art form and is far more complex than anyone realizes. Scale is important, sure, but what you really need is scale+time+intense cost competition. In that environment, it is very hard to start on a significantly different chemistry to compete with lithium-ion. (LiFePO4 is similar enough in manufacturing.) IMO the only place you could start this is China, which would leave BYD and CATL as the only two that could pull it off.

Software engineering is like this too. We reuse existing libraries based on how mature they are, because it's less development time/cost/risk, even though the actual product ends up being very complex under the hood. Very similar principle of finding local maxima.

For what it's worth, non-portable battery storage these days is mostly lithium iron batteries. Which are, yes, heavier; but are superior to lithium-ion in most other ways.

Lithium iron batteries are still lithium ion batteries

Lithium became drastically cheaper, but has yet to achieve relevance in term of grid scale storage. The US uses 12 TWh of electricity per day. The world used 60 TWh. Global lithium ion battery production is around 600 GWh. Most lithium storage systems are on the order of megawatt hours or single digit gigawatt hours.

It can be very useful for grid stabilization at the scale of seconds to minutes (both with charge and discharge).You don't need that much capacity to do that.

It is simply the amount of R&D investment already done and manufacturing pipeline scale that favors Lithium. But if trend continues in couple of years, sodium should have all that market.

And then maybe the voices will finally go silent, saying we cannot do battery grid storage in big numbers, because lithium is limited.

There are other issues with older battery chemistries that make them less attractive than lithium. Discharge rate and various issues with charge cycles among them.

It's mostly durability AFAIK - lead-acid is heavy, but it's cycle life is actually pretty poor. They're used as car auxillary batteries because they do have very nice properties for that specific application with ICE engines (namely, a nice resistive charging curve - they absorb the sort of noisy power you get from an alternator very well).

Not all lead-acid batteries are like car starter batteries: deep-cycle batteries are the same basic technology but they're actually good at being discharged heavily and recharging over and over. They're not good at supplying tons of current quickly, though, which is what's needed for a starter battery.

There's also vanadium flow batteries that seem to be improving and might be good enough to provide a smoother peak capacity.

https://www.reddit.com/r/dataisbeautiful/comments/17r9q6s/co...

Range is actually not that important to most people in China or Europe. If you use your car to commute and you can charge when you park then even 100 miles of range is plenty.

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