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You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an

by joshvm 2y ago

You would be amazed how many battery packs are multiple 18650s in a trenchcoat. Even EV battery packs use them. Though it does raise the question - wouldn't an old EV battery be a better solution than stripping apart laptops?

ianferrel 2y ago
Probably, but EV batteries are large enough that there might be an industrial recycling process for them, while old laptop batteries are basically free because it's too much labor to extract useful value from them.
- edaemon 2y ago
  I'm pretty sure most industrial recycling methods for lithium batteries involve grinding them up, so pack size isn't as much a factor as sheer volume. I think there just wasn't much juice for the squeeze until demand from EVs made recycling worthwhile. Here's a video inside a recycling plant: https://www.youtube.com/watch?v=s2xrarUWVRQ https://www.youtube.com/watch?v=s2xrarUWVRQ
Workaccount2 2y ago
>You would be amazed how many battery packs are multiple 18650s in a trenchcoat $50 of 18650s in a $500 trenchcoat with DRM protection. So wasteful.
- HPsquared 2y ago
  "Cheaply made, not cheap to buy!"
- 0_____0 2y ago
  When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery. Believe it or not there is actual engineering that goes into making batteries beyond spot welding them to an interconnect and stuffing them into $.50 of ABS enclosure.
  - Workaccount2 2y ago
    The "actual engineering" you are referring to is a $1.00 BMS board. We are well past the point where we should have standardized batteries. We have bunch of standardized wall outlets that accommodate an array of "non-zero chance of literally killing your users" end products. No reason for battery packs to not be standardized (other than vendor lock in).
    - 0_____0 2y ago
      I'm sorry but you're dead wrong about the BMS. BMS doesn't address any of the things I listed. You're also wrong about standardization - standarization at the cell form factor level is correct. Different applications have different capacity vs power density requirements, temperature range requirements, cost, lifecycle... a pouch cell that goes in a drone looks a lot like one that goes in a cell phone but they're optimized for completely different workloads. Also we already have standardized interfaces for external batteries with most power banks using USB-C, so in a way your wish has already come true.
      - Workaccount2 2y ago
        Ironically this news dropped yesterday while we were having this discussion https://www.protoolreviews.com/doge-mandates-power-tool-manufacturers-use-same-battery/ https://www.protoolreviews.com/doge-mandates-power-tool-manu... Probably the only thing I can agree with doge on.
  - znpy 2y ago
    > When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery. Linus from Linus Tech Tips made a few episodes on building a battery out of individual 18650 cells, and one of the thing he stressed (as in, underlined) a lot on is that spot-welding cells is extremely dangerous and there aren't easy ways to put out a lithium fire. Water is not only not going to help you, it's going to make things worse. You __have__ to have a bucket of sand with you and if anything goes even slightly wrong you just toss everything in the bucket of sand and bring the whole bucket outside.
0_____0 2y ago
There's a lot that goes into manufacturing battery packs beyond the cells. How's your thermal path to ambient in your home wall battery? How is the inter-cell thermal isolation? Is there a path for gas discharge in the event of a cell failure? Is the pack appropriately fused at the cell or module level? When a cell fails, does it take the whole pack with it, catch someone's apartment building on fire and kill a family of 5, or merely become stinky with a hotspot visible on IR? How good is your cell acceptance testing? Do you do X-ray inspection for defects, do ESR vs cycle and potentially destructive testing on a sample of each lot? When a module fails health checks in the field, will you know which customers to proactively contact, and which vendor to reassess? Yeah lots of batteries are 18650/26650 in a trenchcoat. The trenchcoats run the gamut from "good, fine" to "you will die of smoke inhalation and have a closed casket" in quality and I think that bears mentioning.
- lifeisstillgood 2y ago
  I get that the trenchcoat needs to be well designed and tested, but I am still flat out amazed that you both agree with “meh, most battery packs are made up of rechargeable domestic batteries you find in a kids toy” I just assumed there was … special stuff in there
  - kadoban 2y ago
    There's a lot of risk in creativity when you're selling crap to the public at scale. Way better to just use what everyone else is using.
    - 0_____0 2y ago
      For most things cylindrical cells are the right answer. They don't puff up, they're available with protection circuits, they're cheap and highly available, you can get them in a variety of sizes and capacities, even in different chemistries. Using a custom cell might make sense if you are making a) one megakajillion of a thing or b) you have extreme volume limits which mean you're probably using a pouch cell. In HW engineering, Not Invented Here syndrome costs you big money. You have to have an actual business case for re-engineering something that already exists plus the capital. 95% with my stuff of the time COTS cylindrical is the answer, which means my shit comes in on budget.
vel0city 2y ago
FWIW a lot of EVs use prismatic cells, not cylinder cells. Tesla, Rivian, and Lucid use cylindrical cells. Hyundai, Volkswagen, BMW, GM, Ford, and BYD all use prismatic cells.
znpy 2y ago
> You would be amazed how many battery packs are multiple 18650s in a trenchcoat Also laptop batteries used to be many (usually three or six) 18650s in a plastic trenchcoat. You could literally rebuild your battery when it died, and pick the cells you liked the most. In theory you could pick higher-quality cells than those you find in the batteries sold on ebay from chinese stores. In theory.
mmcwilliams 2y ago
That depends on the problem you're trying to solve. If it's only to build a home power system, sure, but if the goal is "I want to prevent these laptop batteries from ending up in a landfill" then using an old EV battery doesn't really help you much.

by joshvm 2y ago

ianferrel 2y ago

Probably, but EV batteries are large enough that there might be an industrial recycling process for them, while old laptop batteries are basically free because it's too much labor to extract useful value from them.

edaemon 2y ago
I'm pretty sure most industrial recycling methods for lithium batteries involve grinding them up, so pack size isn't as much a factor as sheer volume. I think there just wasn't much juice for the squeeze until demand from EVs made recycling worthwhile. Here's a video inside a recycling plant: https://www.youtube.com/watch?v=s2xrarUWVRQ https://www.youtube.com/watch?v=s2xrarUWVRQ

Workaccount2 2y ago

>You would be amazed how many battery packs are multiple 18650s in a trenchcoat $50 of 18650s in a $500 trenchcoat with DRM protection. So wasteful.

HPsquared 2y ago
"Cheaply made, not cheap to buy!"
0_____0 2y ago
When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery. Believe it or not there is actual engineering that goes into making batteries beyond spot welding them to an interconnect and stuffing them into $.50 of ABS enclosure.
- Workaccount2 2y ago
  The "actual engineering" you are referring to is a $1.00 BMS board. We are well past the point where we should have standardized batteries. We have bunch of standardized wall outlets that accommodate an array of "non-zero chance of literally killing your users" end products. No reason for battery packs to not be standardized (other than vendor lock in).
  - 0_____0 2y ago
    I'm sorry but you're dead wrong about the BMS. BMS doesn't address any of the things I listed. You're also wrong about standardization - standarization at the cell form factor level is correct. Different applications have different capacity vs power density requirements, temperature range requirements, cost, lifecycle... a pouch cell that goes in a drone looks a lot like one that goes in a cell phone but they're optimized for completely different workloads. Also we already have standardized interfaces for external batteries with most power banks using USB-C, so in a way your wish has already come true.
    - Workaccount2 2y ago
      Ironically this news dropped yesterday while we were having this discussion https://www.protoolreviews.com/doge-mandates-power-tool-manufacturers-use-same-battery/ https://www.protoolreviews.com/doge-mandates-power-tool-manu... Probably the only thing I can agree with doge on.
- znpy 2y ago
  > When battery packs that have a non-zero chance of literally killing your users are commonplace, it actually does make sense to vendor-lock the battery. Linus from Linus Tech Tips made a few episodes on building a battery out of individual 18650 cells, and one of the thing he stressed (as in, underlined) a lot on is that spot-welding cells is extremely dangerous and there aren't easy ways to put out a lithium fire. Water is not only not going to help you, it's going to make things worse. You __have__ to have a bucket of sand with you and if anything goes even slightly wrong you just toss everything in the bucket of sand and bring the whole bucket outside.

0_____0 2y ago

There's a lot that goes into manufacturing battery packs beyond the cells. How's your thermal path to ambient in your home wall battery? How is the inter-cell thermal isolation? Is there a path for gas discharge in the event of a cell failure? Is the pack appropriately fused at the cell or module level? When a cell fails, does it take the whole pack with it, catch someone's apartment building on fire and kill a family of 5, or merely become stinky with a hotspot visible on IR? How good is your cell acceptance testing? Do you do X-ray inspection for defects, do ESR vs cycle and potentially destructive testing on a sample of each lot? When a module fails health checks in the field, will you know which customers to proactively contact, and which vendor to reassess? Yeah lots of batteries are 18650/26650 in a trenchcoat. The trenchcoats run the gamut from "good, fine" to "you will die of smoke inhalation and have a closed casket" in quality and I think that bears mentioning.

lifeisstillgood 2y ago
I get that the trenchcoat needs to be well designed and tested, but I am still flat out amazed that you both agree with “meh, most battery packs are made up of rechargeable domestic batteries you find in a kids toy” I just assumed there was … special stuff in there
- kadoban 2y ago
  There's a lot of risk in creativity when you're selling crap to the public at scale. Way better to just use what everyone else is using.
  - 0_____0 2y ago
    For most things cylindrical cells are the right answer. They don't puff up, they're available with protection circuits, they're cheap and highly available, you can get them in a variety of sizes and capacities, even in different chemistries. Using a custom cell might make sense if you are making a) one megakajillion of a thing or b) you have extreme volume limits which mean you're probably using a pouch cell. In HW engineering, Not Invented Here syndrome costs you big money. You have to have an actual business case for re-engineering something that already exists plus the capital. 95% with my stuff of the time COTS cylindrical is the answer, which means my shit comes in on budget.

vel0city 2y ago

FWIW a lot of EVs use prismatic cells, not cylinder cells. Tesla, Rivian, and Lucid use cylindrical cells. Hyundai, Volkswagen, BMW, GM, Ford, and BYD all use prismatic cells.

znpy 2y ago

> You would be amazed how many battery packs are multiple 18650s in a trenchcoat Also laptop batteries used to be many (usually three or six) 18650s in a plastic trenchcoat. You could literally rebuild your battery when it died, and pick the cells you liked the most. In theory you could pick higher-quality cells than those you find in the batteries sold on ebay from chinese stores. In theory.

mmcwilliams 2y ago

That depends on the problem you're trying to solve. If it's only to build a home power system, sure, but if the goal is "I want to prevent these laptop batteries from ending up in a landfill" then using an old EV battery doesn't really help you much.