4 ms·

When the battery dies, why is it essentially junk? Can't one just swap a new battery into it? Or are you saying that because it would cost 10K+ to do that?

AtlasBarfed 4y ago
Replacement batteries aren't exactly like engines either. Can you replace an old big block V8 with a rotary compact engine? Not typically. A battery just has to deliver electric current. If your electric car you bought in 1998 is NMC chemistry, and you replace that pack in 2025 with a 200 wh/kg (that is, about the same density) sodium ion chemistry battery that costs half of what the NMC would, is there some massive overhaul to the system? Maybe the battery management software needs a different set of parameters, but that's about it. Now, the cell-to-frame... well, that's a different issue. Point is, ICE engines cost what they cost. There's no magic technology coming (not compression-combusted gasoline like Mazda has, or even the inside-out rotary will save ICE). People don't appreciate what the forthcoming 150 wh/kg sodium ion batteries and 200-230 wh/kg LFP batteries mean for almost all urban and suburban vehicles. These batteries also don't have runaway fires, so they don't lose functional density at the pack level like NMC chemistries. So if you had some Tesla going 400 miles with 260 wh/kg NMC, that was ACTUALLY about 180 wh/kg at pack level with cooling and safety, the 200 wh/kg LFP using modern Cell-to-Pack techniques, is that same battery. No Nickel. No Cobalt. Lithium is the limiter (and lithium supplies are largely constrained by lack of development, not scarcity like Nickel and especially Cobalt). So if 200 wh/kg LFP can do 400+ mile cars, the math should be pretty simple on 150 wh/kg sodium ion. That's a 300+ mile car. No lithium needed even. The roadmap for LFP is 230 wh/kg in mass production later this year. 200 wh/kg is already scaling up. The roadmap for Sodium Ion is 200 wh/kg in a year or two, we'll see on that. And once sulfur-based chemistries come online, which are allegedly 2-3x as dense as NMC, look out. That means battery packs that are 45% to 30% of the size of previous ones. Also, yes batteries aren't junk when they need to be replaced. There will be a couple options: 1) the pack is likely 60-70% capacity of the original. It can be used for home powerwalls, grid storage, etc. 2) the pack can be torn apart and individual cells tested/harvested that still function, and those are reintegrated in other uses (lawnmowers? Power tools? powerwalls? Batteries are useful EVERYWHERE). 3) Recycle the whole pack to get the materials / metals back. That's what is interesting about battery packs. They don't catastrophically die typically. Their EoL is a gradual failure, but they are still useful. Can an ICE engine near its end of life be torn up into hundreds of little engines and repackaged into toys, tools, security cameras, leaf blowers? No? An EV battery can. So the battery being a major component cost isn't a total loss, more like a depreciating asset component. It will still have inherent value in many ways, far better than the scrap metal value of an engine from an ICE drivetrain.
- ElijahLynn 4y ago
  Great perspective here, thanks!

AtlasBarfed 4y ago

Replacement batteries aren't exactly like engines either. Can you replace an old big block V8 with a rotary compact engine? Not typically. A battery just has to deliver electric current. If your electric car you bought in 1998 is NMC chemistry, and you replace that pack in 2025 with a 200 wh/kg (that is, about the same density) sodium ion chemistry battery that costs half of what the NMC would, is there some massive overhaul to the system? Maybe the battery management software needs a different set of parameters, but that's about it. Now, the cell-to-frame... well, that's a different issue. Point is, ICE engines cost what they cost. There's no magic technology coming (not compression-combusted gasoline like Mazda has, or even the inside-out rotary will save ICE). People don't appreciate what the forthcoming 150 wh/kg sodium ion batteries and 200-230 wh/kg LFP batteries mean for almost all urban and suburban vehicles. These batteries also don't have runaway fires, so they don't lose functional density at the pack level like NMC chemistries. So if you had some Tesla going 400 miles with 260 wh/kg NMC, that was ACTUALLY about 180 wh/kg at pack level with cooling and safety, the 200 wh/kg LFP using modern Cell-to-Pack techniques, is that same battery. No Nickel. No Cobalt. Lithium is the limiter (and lithium supplies are largely constrained by lack of development, not scarcity like Nickel and especially Cobalt). So if 200 wh/kg LFP can do 400+ mile cars, the math should be pretty simple on 150 wh/kg sodium ion. That's a 300+ mile car. No lithium needed even. The roadmap for LFP is 230 wh/kg in mass production later this year. 200 wh/kg is already scaling up. The roadmap for Sodium Ion is 200 wh/kg in a year or two, we'll see on that. And once sulfur-based chemistries come online, which are allegedly 2-3x as dense as NMC, look out. That means battery packs that are 45% to 30% of the size of previous ones. Also, yes batteries aren't junk when they need to be replaced. There will be a couple options: 1) the pack is likely 60-70% capacity of the original. It can be used for home powerwalls, grid storage, etc. 2) the pack can be torn apart and individual cells tested/harvested that still function, and those are reintegrated in other uses (lawnmowers? Power tools? powerwalls? Batteries are useful EVERYWHERE). 3) Recycle the whole pack to get the materials / metals back. That's what is interesting about battery packs. They don't catastrophically die typically. Their EoL is a gradual failure, but they are still useful. Can an ICE engine near its end of life be torn up into hundreds of little engines and repackaged into toys, tools, security cameras, leaf blowers? No? An EV battery can. So the battery being a major component cost isn't a total loss, more like a depreciating asset component. It will still have inherent value in many ways, far better than the scrap metal value of an engine from an ICE drivetrain.

ElijahLynn 4y ago
Great perspective here, thanks!