6 ms·

The raw materials may continue to cost more for EVs. Motor windings are generally copper, and batteries contain lithium and (usually) cobalt and nickel. Perma

by elihu 6y ago

The raw materials may continue to cost more for EVs. Motor windings are generally copper, and batteries contain lithium and (usually) cobalt and nickel. Permanent magnet motors sometimes contain rare earths. One could make an EV with aluminum motor windings and electrical cabling, no rare earth magnets, and lithium iron phosphate batteries. That would keep expensive materials to a minimum. EVs don't need a catalytic converter, so that's a big thing in their favor. I'm looking forward to mass manufacturing continuing to bring down EV component prices. I think we're a long ways from the point where material costs are the bulk of the expense.

the_cat_kittles 6y ago
cmon man. the total weight of pricey metals in a car is so low, there is no way its going to offset the cost of precision machining. tolerances < 1 thou and callouts for surface finish and perpendicularity are expensive!
- jeffreyrogers 6y ago
  I'm sure a motor is cheaper than an engine (less steps to make), but they still require precision manufacturing, and all the other parts aside from the motor (driveshaft, axles, brakes, etc.) are more or less the same. Plus, the cost of those other materials is going to increase if demand for EVs goes up.
  - the_cat_kittles 6y ago
    evs could drive lithium but i really doubt they would influence copper that much, since it is used so much already
    - jeffreyrogers 6y ago
      I think the more constraining commodities are things like rare earths[0] and other important metals like cobalt. [0]: I know they aren't that rare, but they aren't mined/processed in many places and it takes a long time to bring a new mine online.
- elihu 6y ago
  Somehow car manufacturers are able to make engines, transmissions, transaxles, and differentials really cheaply, so apparently all that precision manufacturing doesn't really cost all that much when producing at high volume. This should be equally true of EVs and combustion-engine cars. Raw material costs might still be less than the manufacturing costs, but they're pretty hard to avoid. Also, materials that are cheap now might not be if demand grows faster than supply.
- jbay808 6y ago
  Hard to say. Those tolerances would be expensive in general purpose machine work, but in engines those tolerances have been in place since at least the 1930s, and so economies of scale bring those costs down (ie, using specialized machines that are really good at boring precision holes and measuring them. The costs of those machines get amortized over every engine).
Robotbeat 6y ago
Tesla already uses aluminum for power cabling because it’s cheap and lighter weight. Tesla Model S were induction motors (at first at least) with no rare earths, and Tesla is partnering with CATL for lithium iron phosphate batteries in lower cost versions of, if I believe, Model 3 and Y.
- esaym 6y ago
  Note to replace copper wiring with aluminum, you have to go up at least one gauge size.
  - elihu 6y ago
    Yeah, aluminum is a worse conductor so you need thicker cable. It's less dense, though, so I think it usually comes out as being lighter. Thicker cables can be more inconvenient. I think aluminum also tends to have more problems with oxidation causing too much resistance at electrical contacts. I think for motors generally you just end up with a larger motor for the same amount of power.
    - Bubbadoo 6y ago
      All points you make are very true. In addition, aluminum tends to crack as it ages and you'll find aluminum wiring is usually a culprit in electrical fires. In the world of mobile electronics, it's usually looked down upon as the cheapest alternative when compared to real copper conductor used in higher quality automotive wiring.
      - Robotbeat 6y ago
        It only requires proper engineering of the connection. Aluminum itself doesn’t crack in properly engineered joints. What fails in old houses is shoddy connections. If people look down upon it, it’s because they’re either lazy or ambivalent. It’s the superior performance solution in some situations.
  - CamperBob2 6y ago
esaym 6y ago
> EVs don't need a catalytic converter, so that's a big thing in their favor. I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, and weld in a universal fit one that we'd get from the auto store for $20. Then charge the customer $200-$400 for labor. I still see universal fit ones[0] although they are $80 now. But still, if you aren't dumping raw fuel or oil into your exhaust, cats are basically good for 300k+ "normal" driving miles. I assume they are expensive now because they are all mostly specially made/custom fit since all car manufactures keep cramming bigger and bigger engines into smaller and smaller spaces. And while I'm ranting, there's always a negative for every positive and no doubt for the catalytic converter. For a catalytic converter to convert "greenhouse gases", the engine has to be burning fuel at a perfect air:fuel ratio of 14.7:1. While cruising down the highway, an engine could easily save fuel by running a more lean mixture, but this would cause more "greenhouse gases" to go out. So choose your poison I suppose. [0] https://imgur.com/a/7X0sPlk https://imgur.com/a/7X0sPlk
- elihu 6y ago
  I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health. The main greenhouse gas from a car is carbon dioxide. The amount you create is directly proportional to the amount of fuel you burn. I don't know why modern cats are expensive; it might have to do with the price of platinum, palladium, and so on, and the relative amount of those materials. A cheap generic cat might have the bare minimum amount of catalyst, and might not do a very good job.
  - czinck 6y ago
    > I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health. I thought the same thing, but interestingly that's only kinda true. If anything, cats increase CO_2 as a desired end goal, because it's better to have CO_2 than CO or NO_x (or so the EPA has decided, I am no where near qualified to decide that). The issue with running too lean is that the reactions in the cat would rather use plain O_2 than NO_x, and so if you have too much O_2 (lean) you won't get rid of any of the NO_x [0]. Before looking into this I thought lean engines produced more NO_x because of higher cylinder temps or something like that (which might be true as well). Cats not reducing NO_x when lean is essentially why Volkswagen (and practically every other manufacturer has been caught doing similar things to diesel engines) was cheating the test. Diesels have no throttle so they are (almost) always lean, typically very lean. This does make me wonder, though, does running lean actually increase fuel efficiency? Obviously rich lowers fuel economy because not all the fuel burns, but assuming it all burns what does it matter if you have 1 gram of fuel to 15 grams of air in the cylinder, or 1 gram of fuel to 18 grams of air in the cylinder? You'll still get the same amount of energy, right? [0] https://en.wikipedia.org/wiki/Catalytic_converter#Three-way https://en.wikipedia.org/wiki/Catalytic_converter#Three-way

by elihu 6y ago

the_cat_kittles 6y ago

cmon man. the total weight of pricey metals in a car is so low, there is no way its going to offset the cost of precision machining. tolerances < 1 thou and callouts for surface finish and perpendicularity are expensive!

jeffreyrogers 6y ago
I'm sure a motor is cheaper than an engine (less steps to make), but they still require precision manufacturing, and all the other parts aside from the motor (driveshaft, axles, brakes, etc.) are more or less the same. Plus, the cost of those other materials is going to increase if demand for EVs goes up.
- the_cat_kittles 6y ago
  evs could drive lithium but i really doubt they would influence copper that much, since it is used so much already
  - jeffreyrogers 6y ago
    I think the more constraining commodities are things like rare earths[0] and other important metals like cobalt. [0]: I know they aren't that rare, but they aren't mined/processed in many places and it takes a long time to bring a new mine online.
elihu 6y ago
Somehow car manufacturers are able to make engines, transmissions, transaxles, and differentials really cheaply, so apparently all that precision manufacturing doesn't really cost all that much when producing at high volume. This should be equally true of EVs and combustion-engine cars. Raw material costs might still be less than the manufacturing costs, but they're pretty hard to avoid. Also, materials that are cheap now might not be if demand grows faster than supply.
jbay808 6y ago
Hard to say. Those tolerances would be expensive in general purpose machine work, but in engines those tolerances have been in place since at least the 1930s, and so economies of scale bring those costs down (ie, using specialized machines that are really good at boring precision holes and measuring them. The costs of those machines get amortized over every engine).

Robotbeat 6y ago

Tesla already uses aluminum for power cabling because it’s cheap and lighter weight. Tesla Model S were induction motors (at first at least) with no rare earths, and Tesla is partnering with CATL for lithium iron phosphate batteries in lower cost versions of, if I believe, Model 3 and Y.

esaym 6y ago
Note to replace copper wiring with aluminum, you have to go up at least one gauge size.
- elihu 6y ago
  Yeah, aluminum is a worse conductor so you need thicker cable. It's less dense, though, so I think it usually comes out as being lighter. Thicker cables can be more inconvenient. I think aluminum also tends to have more problems with oxidation causing too much resistance at electrical contacts. I think for motors generally you just end up with a larger motor for the same amount of power.
  - Bubbadoo 6y ago
    All points you make are very true. In addition, aluminum tends to crack as it ages and you'll find aluminum wiring is usually a culprit in electrical fires. In the world of mobile electronics, it's usually looked down upon as the cheapest alternative when compared to real copper conductor used in higher quality automotive wiring.
    - Robotbeat 6y ago
      It only requires proper engineering of the connection. Aluminum itself doesn’t crack in properly engineered joints. What fails in old houses is shoddy connections. If people look down upon it, it’s because they’re either lazy or ambivalent. It’s the superior performance solution in some situations.
- CamperBob2 6y ago

esaym 6y ago

> EVs don't need a catalytic converter, so that's a big thing in their favor. I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, and weld in a universal fit one that we'd get from the auto store for $20. Then charge the customer $200-$400 for labor. I still see universal fit ones[0] although they are $80 now. But still, if you aren't dumping raw fuel or oil into your exhaust, cats are basically good for 300k+ "normal" driving miles. I assume they are expensive now because they are all mostly specially made/custom fit since all car manufactures keep cramming bigger and bigger engines into smaller and smaller spaces. And while I'm ranting, there's always a negative for every positive and no doubt for the catalytic converter. For a catalytic converter to convert "greenhouse gases", the engine has to be burning fuel at a perfect air:fuel ratio of 14.7:1. While cruising down the highway, an engine could easily save fuel by running a more lean mixture, but this would cause more "greenhouse gases" to go out. So choose your poison I suppose. [0] https://imgur.com/a/7X0sPlk https://imgur.com/a/7X0sPlk

elihu 6y ago
I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health. The main greenhouse gas from a car is carbon dioxide. The amount you create is directly proportional to the amount of fuel you burn. I don't know why modern cats are expensive; it might have to do with the price of platinum, palladium, and so on, and the relative amount of those materials. A cheap generic cat might have the bare minimum amount of catalyst, and might not do a very good job.
- czinck 6y ago
  > I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health. I thought the same thing, but interestingly that's only kinda true. If anything, cats increase CO_2 as a desired end goal, because it's better to have CO_2 than CO or NO_x (or so the EPA has decided, I am no where near qualified to decide that). The issue with running too lean is that the reactions in the cat would rather use plain O_2 than NO_x, and so if you have too much O_2 (lean) you won't get rid of any of the NO_x [0]. Before looking into this I thought lean engines produced more NO_x because of higher cylinder temps or something like that (which might be true as well). Cats not reducing NO_x when lean is essentially why Volkswagen (and practically every other manufacturer has been caught doing similar things to diesel engines) was cheating the test. Diesels have no throttle so they are (almost) always lean, typically very lean. This does make me wonder, though, does running lean actually increase fuel efficiency? Obviously rich lowers fuel economy because not all the fuel burns, but assuming it all burns what does it matter if you have 1 gram of fuel to 15 grams of air in the cylinder, or 1 gram of fuel to 18 grams of air in the cylinder? You'll still get the same amount of energy, right? [0] https://en.wikipedia.org/wiki/Catalytic_converter#Three-way https://en.wikipedia.org/wiki/Catalytic_converter#Three-way