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This took a few reads to parse. There are two kinds of batteries: (1) a low-density LFP that has a great lifetime, (2) a simulated manganese using Nickel manga

This took a few reads to parse. There are two kinds of batteries: (1) a low-density LFP that has a great lifetime, (2) a simulated manganese using Nickel manganese cobalt that has a poor lifetime but great density. The former cycles frequently for short trips, and the latter recharges it during the long ones.

HPsquared 3y ago
That's pretty clever. It leverages the fact that most people make a large number of short trips, and a smaller number of long trips. Also if it's modular enough, this design could allow replacing one or the other battery if the user does lots of short trips, or lots of long trips. Also could let the manufacturer do market segmentation, e.g. a high performance model with no LFP, and both parts of the "high-performance" chemistry - and a base model that's 100% LFP.
- deleted 3y ago
  [deleted]
- extraduder_ire 3y ago
  Reminds me of how some SSDs do wear levelling, where they treat cells like they're one bit while the drive's empty and go up to four bits per cell as it fills up, with a speed penalty.
- callalex 3y ago
  Considering that you can’t even change the 12v lead-acid battery in a BMW vehicle (ICE nor EV) without paying the dealer for programming, or some extensive hacking, I don’t hold out much hope for modular replacement.
keenmaster 3y ago
You need more LFP to carry the weight of the manganese battery though (increasing cost), and all the extra weight can affect driving dynamics. Maybe both the cost and weight increase are minimal but that’s what came to mind. It’s a great idea though.
- adam_arthur 3y ago
  EVs already have far better driving dynamics than gas cars... doesn't seem like what designers should be optimizing for, or what the average consumer will care most about.
  - keenmaster 3y ago
    “Far better driving dynamics than gas cars”? No way. Go throw a BMW 3-series around some corners and compare to the Model 3 - you will feel the weight of the batteries. I would have said compare to a Porsche but that’s a different price range. Note: I’m a big fan of EVs. I’m just saying that handling is one of their weaknesses until battery density gets a lot better.
    - adam_arthur 3y ago
      The average people don't buy BMW or Tesla, they buy Honda CR-V. And they'll appreciate 500mi range far more than being able to take turns fast
      - fragmede 3y ago
        Zero people drive 500 miles in a straight line on a daily basis though, so cornering ability is more important than 500 miles of range, especially when most gasoline cars (several diesels do) don't get that much range in a single tank. The biggest change for EVs is the ability to charge the car at home, though, so you wake up every morning with a full tank of "gas". An EV with only 50 miles of range would do great for most people if they had home charging given how many miles "most people" drive in a day. I don't work for BMW (or Honda, or Tesla) though, so what do I know.
        yourusername 3y ago
        If people have to choose between being able to drive 500 miles with good enough handling and 200 miles with razor sharp sportscar handling the vast majority will pick the 500 mile car. Handling has long been good enough, most people don't get anywhere near what even their basic econobox can do.

HPsquared 3y ago

That's pretty clever. It leverages the fact that most people make a large number of short trips, and a smaller number of long trips. Also if it's modular enough, this design could allow replacing one or the other battery if the user does lots of short trips, or lots of long trips. Also could let the manufacturer do market segmentation, e.g. a high performance model with no LFP, and both parts of the "high-performance" chemistry - and a base model that's 100% LFP.

deleted 3y ago
[deleted]
extraduder_ire 3y ago
Reminds me of how some SSDs do wear levelling, where they treat cells like they're one bit while the drive's empty and go up to four bits per cell as it fills up, with a speed penalty.
callalex 3y ago
Considering that you can’t even change the 12v lead-acid battery in a BMW vehicle (ICE nor EV) without paying the dealer for programming, or some extensive hacking, I don’t hold out much hope for modular replacement.

keenmaster 3y ago

You need more LFP to carry the weight of the manganese battery though (increasing cost), and all the extra weight can affect driving dynamics. Maybe both the cost and weight increase are minimal but that’s what came to mind. It’s a great idea though.

adam_arthur 3y ago
EVs already have far better driving dynamics than gas cars... doesn't seem like what designers should be optimizing for, or what the average consumer will care most about.
- keenmaster 3y ago
  “Far better driving dynamics than gas cars”? No way. Go throw a BMW 3-series around some corners and compare to the Model 3 - you will feel the weight of the batteries. I would have said compare to a Porsche but that’s a different price range. Note: I’m a big fan of EVs. I’m just saying that handling is one of their weaknesses until battery density gets a lot better.
  - adam_arthur 3y ago
    The average people don't buy BMW or Tesla, they buy Honda CR-V. And they'll appreciate 500mi range far more than being able to take turns fast
    - fragmede 3y ago
      Zero people drive 500 miles in a straight line on a daily basis though, so cornering ability is more important than 500 miles of range, especially when most gasoline cars (several diesels do) don't get that much range in a single tank. The biggest change for EVs is the ability to charge the car at home, though, so you wake up every morning with a full tank of "gas". An EV with only 50 miles of range would do great for most people if they had home charging given how many miles "most people" drive in a day. I don't work for BMW (or Honda, or Tesla) though, so what do I know.
      - yourusername 3y ago
        If people have to choose between being able to drive 500 miles with good enough handling and 200 miles with razor sharp sportscar handling the vast majority will pick the 500 mile car. Handling has long been good enough, most people don't get anywhere near what even their basic econobox can do.