[HN Gopher] Giving EV batteries a second life for sustainability... ___________________________________________________________________ Giving EV batteries a second life for sustainability and profit Author : prostoalex Score : 26 points Date : 2021-04-07 00:26 UTC (22 hours ago) (HTM) web link (techcrunch.com) (TXT) w3m dump (techcrunch.com) | elihu wrote: | This seems like it would be complicated by the many different | chemistries and form factors available, and the wide variability | between packs depending on how old or well-taken-care-of they | are. | | If one were to set out to create a single large battery out of | massive array of extremely heterogenous individual battery packs, | what would that look like? I guess you could pair each battery | pack with its own individual charger and inverter so they can all | feed into some common bus at a given voltage and frequency -- | sort of like the "microinverter" setup for solar panels. | | You could cut down on heterogeneity by only using one type of | battery in one installation, and trade batteries between | installations or even with external companies so everyone can get | matching sets. Sort of like the card game Pit. You could also bin | the batteries by quality, like how manufacturers of vacuum tubes | have a hard time replicated electrical characteristics exactly | from one tube to the next, so they sort them into bins after | manufacture and ship them out as matched sets that came from the | same bin. | rektide wrote: | Making heterogenous individual packs sounds like an absolute | disaster. That's why this is various car companies teaming up | with specific folk: because they'll have big quantities of | cells from each individual vehicle they get, and there will | only be so many different types of cell. There will be big | supplies of a couple different cells, ready to go in to | applications of all different sorts. | | As it so happens, there's already a lot of agreement. Many many | cells are either 18 mm, 21mm or 28 mm diameter cylinders & | 650-700 mm long. "18650" cell is very common. 28650 used to be | a "big" cell but it's not around as much I feel like. "2170" is | a "21700" that is increasingly popular. Most of these cells | have similar charge behavior, of applying a fixed amps up to a | point, perhaps with temperature sensors to detect problems/slow | down, and then a slower finishing charge, that ends around 4.2V | per cell. | | Using solar grid-tie micro-inverters would probably work fine | to join together a bunch of different packs. | Reason077 wrote: | And now, Tesla are developing an even bigger "4680" cell: | | https://evannex.com/blogs/news/tesla-s-4680-cell-is-a- | stroke... | sokoloff wrote: | Some modern LEDs are also binned parts, as are CPUs. ___________________________________________________________________ (page generated 2021-04-07 23:00 UTC)