4 ms·

The 24/7/365 aspect can be solved by moving them sufficiently underground. Underground environments are naturally the yearly average temperature of the surface.

adrianmonk 8y ago
And even if digging is too expensive, there's another option: buffer the buffer with a big tank of water. That is, put the tank of electrolyte inside an outer tank of water. As long as your average temperature is between 10C and 40C, with sufficient volume of water you'd have enough thermal mass to ride out the day and night fluctuations. In some climates, you might need to get fancier to try to nudge the temperature in the right direction. Hot climates shouldn't be much of a problem, but even if they are you could use fans or vents to create a system that's insulated and shaded during the day but open to outside air at night. In cold climates, you might want to have a greenhouse kind of setup to capture some extra heat and prevent convection cooling so it stays above 10°C.
- fallingfrog 8y ago
  This might work in Europe but not in the states where the summertime temperature might be around +25 and the wintertime temperature might sometimes reach -25. The lake where my parents live freezes thick enough to drive a pickup truck on it.
  - londons_explore 8y ago
    Read the parent comment again. As long as some of the time temperatures are in a viable range, it isn't a problem.
    - fallingfrog 8y ago
      I would tend to disagree. Even if the water buffer is 20 feet thick, it will freeze all the way through, at least where I live. I mean you can buffer sub-freezing temperatures for a few days, a couple weeks, but not for 6 months.
    - fallingfrog 8y ago
      Oh, and since water expands when it freezes - the container will rupture, too.
- dogma1138 8y ago
  Hot climates are a huge problem because temperatures easily reach 40c in Africa and the Middle East and that is just ambient temperature you are forgetting the heat produced by the battery itself. Li-ion doesn’t have this problem as much heck the PANASONIC NCR-18650 can be discharged safely even at 60c.

adrianmonk 8y ago

And even if digging is too expensive, there's another option: buffer the buffer with a big tank of water. That is, put the tank of electrolyte inside an outer tank of water. As long as your average temperature is between 10C and 40C, with sufficient volume of water you'd have enough thermal mass to ride out the day and night fluctuations. In some climates, you might need to get fancier to try to nudge the temperature in the right direction. Hot climates shouldn't be much of a problem, but even if they are you could use fans or vents to create a system that's insulated and shaded during the day but open to outside air at night. In cold climates, you might want to have a greenhouse kind of setup to capture some extra heat and prevent convection cooling so it stays above 10°C.

fallingfrog 8y ago
This might work in Europe but not in the states where the summertime temperature might be around +25 and the wintertime temperature might sometimes reach -25. The lake where my parents live freezes thick enough to drive a pickup truck on it.
- londons_explore 8y ago
  Read the parent comment again. As long as some of the time temperatures are in a viable range, it isn't a problem.
  - fallingfrog 8y ago
    I would tend to disagree. Even if the water buffer is 20 feet thick, it will freeze all the way through, at least where I live. I mean you can buffer sub-freezing temperatures for a few days, a couple weeks, but not for 6 months.
  - fallingfrog 8y ago
    Oh, and since water expands when it freezes - the container will rupture, too.
dogma1138 8y ago
Hot climates are a huge problem because temperatures easily reach 40c in Africa and the Middle East and that is just ambient temperature you are forgetting the heat produced by the battery itself. Li-ion doesn’t have this problem as much heck the PANASONIC NCR-18650 can be discharged safely even at 60c.