• Hotzilla@sopuli.xyz
    link
    fedilink
    English
    arrow-up
    7
    arrow-down
    7
    ·
    21 hours ago

    TNT has 1162 Wh/kg ratio.

    These new lithium-ion batteries get to 300-400Wh/kg range.

    We are hitting the limit what is doable with energy density. Do you really want to carry 100g of TNT in your pocket or few tons of TNT in vehicle going 100km/h.

    Of course things are not directly comparable, but ball parks.

    • GamingChairModel@lemmy.world
      link
      fedilink
      English
      arrow-up
      13
      ·
      19 hours ago

      Yeah but firewood is like 5 kwh/kg, or 4 times the energy density of TNT. We drive around with wood in our cars all the time.

    • Pup Biru@aussie.zone
      link
      fedilink
      English
      arrow-up
      14
      ·
      21 hours ago

      i’d say stability is more important than energy density

      like gasoline has more than 10x the energy density than tnt and we’re perfectly fine with many kg of that on a vehicle going 100km/h

      a fully fueled vehicle is the equivalent of ~600kg of TNT, but it’s very stable whilst TNT is not

      • Hotzilla@sopuli.xyz
        link
        fedilink
        English
        arrow-up
        1
        ·
        20 hours ago

        That is true, but my small EV the batteries are 500kg, same car with combustion engine only has 40L fuel tank.

        Stability is important, but lithium-ion ain’t really that stable either. Still waiting some solid state to get made.

        • Naia@lemmy.blahaj.zone
          link
          fedilink
          English
          arrow-up
          3
          ·
          18 hours ago

          Lithium Iron Phosphate (LiFe-PO) are actually really stable. Way less likely to catch fire in thermal runaway and don’t lose capacity as easily.

          They just aren’t very energy dense, so you need more weight per wh. They also operate at a lower voltage per cell which means they charge slower.

          They are used in short to med range EVs already, but the lower capacity makes it impractical to put enough for longer range EVs.


          As an aside, I would argue that for the majority of people a large capacity EV battery is a bit of a waste. Mine is ~70Kwh, give or take. In optimal conditions my car estimates 240-250mi at 100%. Over the winter it’s showing anywhere from 140-180mi at 80%.

          I moved cross country right after getting it and drove it 1000 miles. It took a bit longer, than it would in a gas car, but it was doable. Just have to plan segments to get to the next charger and try to charge to 100% with level 2 charging (240v AC) if you can when you stop for the night.

        • village604@adultswim.fan
          link
          fedilink
          English
          arrow-up
          2
          ·
          19 hours ago

          Yeah, lithium ion is a good stopgap while we develop better options, but it’s by no means stable. Get them too hot or puncture a cell and you’re going to have a bad time.

    • UnderpantsWeevil@lemmy.world
      link
      fedilink
      English
      arrow-up
      8
      ·
      19 hours ago

      TNT has 1162 Wh/kg ratio.

      How do you recharge TNT?

      We are hitting the limit what is doable with energy density.

      I mean, we’re definitely running into a problem of how you build a battery without also building a bomb. But the entire point of TNT is rapid thermal expansion. The point of a battery is very low voltage steady release of electrical charge.

      I might also note that C4 has around 6 Mwh/kg. A bit of applied chemistry can go a long way to improving energy efficiency. And that’s before you take advantage of geometry to focus pressure, via a shaped charge.

      Point being, there’s a lot of clever ways to juice a lemon. We’re a long way from the end of the road on battery improvement.

    • explodicle@sh.itjust.works
      link
      fedilink
      English
      arrow-up
      2
      ·
      21 hours ago

      Kinda, yes? Phones already do so much, why not one additional feature to deter theft.

      We’ve got a lot of that going around in the USA right now.