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Toyota is recycling old EV batteries to help power Mazda's production line

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Re: Toyota is recycling old EV batteries to help power Mazda's production line

#61

Post by Dylan16807 »

omgwtfbyobbq wrote: post #32
zhyder wrote: post #4

Neat idea to mix batteries of different age and chemistries. I've wondered why EVs couldn't do that too with some power electronics and SW. If an EV battery could have multiple such modules, it'd: 1) Make it easier to carry a cheaper lighter less-natural-resources-consuming battery most of the time. Go to some "gas station" to rent and add more modules when taking a road trip 2) Make it cheaper to replace the 1 modul…

CATL announced a dual-power battery pack recently. https://technode.com/2025/04/22/catl-says-its-next-gen-dual-...

Clarification, that announcement is for a new version and they're already selling packs with mixed battery chemistries.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#62

Post by londons_explore »

spockz wrote: post #51
londons_explore wrote: post #48

Earlier quoted context omitted.

No EV that I'm aware of has the ability to bypass a single cell in a series string. I have often wondered if it would be worth designing an EV battery that can permanently short out a bad cell in a string, perhaps by deliberately disabling balancing, letting the bad cells voltage fall to zero, and then perhaps having a single use 'bypass' that latches on. It wouldn't be a seamless user experience, because if you disc…

I guess you can put a relais/switch in for each cell in a series but then you need to account for voltage differences when taking them out. Either by over provisioning within the series and rotating in different cells. Or by have other strings take up the slack. Either way you need some form of overbooking / compensating capacity.

Nearly all EV's today would run just fine on 3.7 volts fewer.

My car's high voltage circuitry seems to work down to about half of the nominal voltage.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#63

Post by reactordev »

Dylan16807 wrote: post #60
reactordev wrote: post #58

Earlier quoted context omitted.

More often than not these bad cells can be removed, manufactured a new, and reinstalled. Not 100% but almost good as new. Making your own cells is fun. For Toyota, this is trivial and the energy storage these “left over” batteries provide, given a tinkering, is sufficient.

Your own cells ? Like you put together a lasagna of metal sheets and chemical goops and roll it up?

Nah, you can buy 18650 cells, nickel strips, a spot welder, and make a BMS. Build your own battery pack.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#64

Post by olddustytrail »

lstodd wrote: post #33
stetrain wrote: post #30

Earlier quoted context omitted.

Small 2-stroke engines tend to be worse for pollution emissions (NOx, particulates) despite generally good fuel efficiency.

well, yes, I like the smell of 2T exhaust in the morning. still, even my yamaha majesty 250 of 1992 (4HC-edit) only ate 3.5L/100km despite hauling thrice the mass of that same ovetto.

Of course you do. As long as someone else pays for cleaning up after you. There have always been leeches in the world.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#65

Post by stetrain »

hinkley wrote: post #55
stetrain wrote: post #22

Earlier quoted context omitted.

GM claims that this is exactly how their Ultium battery pack architecture works. It is made up of multiple modules each with their own BMS, and supposedly one module can be replaced without having to be a match in chemistry and degradation to the other modules. I'm unsure if that will actually work so well in practice, where you still need to charge all the cells simultaneously when doing DC fast charging etc. Also a…

You shouldn’t need to charge them all at the same rate. Put in some cells that charge slower, fast charge the rest and continue charging the slower cells until unplugged. Consider for instance fast charging the array to 70% instead of 80%, where 1/3 of the cells are charged to 50% and the rest to 80%.

When all of your cells are connected in a pack of 400-800V connected to a DC fast charger, how do you stop charging the fast cells and continue charging the slower cells?

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#66

Post by Cthulhu_ »

londons_explore wrote: post #41
pornel wrote: post #28

Those who TL;DRd - it's for the factory, not the cars! Old EV batteries are great for energy storage. A worse weight-to-capacity ratio doesn't matter for batteries sitting on the ground. A battery that holds only 70% of its original capacity is considered worn-out for EVs (and even replaced under warranty), but grid storage isn't driving anywhere, so any capacity left is still useful.

If you take car EV batteries and use them for stationary storage when past end-of-life, the fire risk becomes fairly substantial because EV batteries often have a little water ingress, physical damage etc. It can be solved by isolating each battery in its own steel box, but that gets fairly expensive fairly fast.

I've seen a video on the youtube where a battery recycling company does this; they leave the car battery packs in their original housing, which I presume is water resistant enough. Each unit is also connected to a controller, which I also presume monitors battery health, temperature (assuming temp sensors on car battery packs), voltage, etc. If a unit is dying they can safely dispose of it, else, the units were out in the open and with several meters in between, meaning any fire would be unlikely to spread to something else and there's plenty of access opportunities.

Very space inefficient though, but there's more than enough of that in the US.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#67

Post by yabones »

kenhwang wrote: post #15
skhameneh wrote: post #5

This seems very bizarre given Mazda is probably the least (of all "major" manufacturers) focused on EV and electric initiatives. Mazda only had one EV, the MX-30 EV. Less than 600 of the MX-30 EV were sold in the US during its production. It was a complete flop right out of production. Mazda leadership has been notorious for pushing rotary engines and shifting further away from EV initiatives.

Mazda as a company has a very good track record of adopting green production initiatives. For example, they were one of the first to switch to water based paint to reduce VOC emissions, and specifically formulating the paint to not require heat-drying to lower energy use. Their current stance seems to be that PHEVs are better than EVs for the environment because it better matches the driving patterns of the typical c…

Mazda punches way above their weight when it comes to "moonshot" innovation over and over again. Few of them really "succeed" commercially (Rotary engine, miller-cycle engine, HCCI) but I respect them for constantly pushing the technology forward.

* https://en.wikipedia.org/wiki/Mazda_Wankel_engine

* https://en.wikipedia.org/wiki/Miller_cycle

* https://en.wikipedia.org/wiki/Skyactiv#Skyactiv-X

* https://en.wikipedia.org/wiki/Homogeneous_charge_compression...

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#68

Post by Cthulhu_ »

slt2021 wrote: post #37
pornel wrote: post #28

Those who TL;DRd - it's for the factory, not the cars! Old EV batteries are great for energy storage. A worse weight-to-capacity ratio doesn't matter for batteries sitting on the ground. A battery that holds only 70% of its original capacity is considered worn-out for EVs (and even replaced under warranty), but grid storage isn't driving anywhere, so any capacity left is still useful.

this is like picking up unfinished cigarette butts and making few finals puffs before burning your mouth. worn-out batteries can swell and fail spectacularly, with fireworks

Except that the cigarrette is only 30% smoked and still perfectly fine to smoke for a while longer (if you insist on an analogy).

Car battery packs are really good; even the oldest Teslas are only now getting to less than 80% capacity. They are designed not to swell/fail if they're worn, else there would be a lot more car fires.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#69

Post by lstodd »

olddustytrail wrote: post #64
lstodd wrote: post #33

Earlier quoted context omitted.

well, yes, I like the smell of 2T exhaust in the morning. still, even my yamaha majesty 250 of 1992 (4HC-edit) only ate 3.5L/100km despite hauling thrice the mass of that same ovetto.

Of course you do. As long as someone else pays for cleaning up after you. There have always been leeches in the world.

your comment reminds me of a rant by a severely clueless person who insisted that we must conserve water despite living on an island in a middle of a second largest european reservoir.

which is utterly pointless.

Re: Toyota is recycling old EV batteries to help power Mazda's production line

#70

Post by Uvix »

toast0 wrote: post #27
smileysteve wrote: post #14

Earlier quoted context omitted.

Re: 1, ignoring the complexities, is really interesting but depending on the effort to change our battery banks quickly makes renting a car more feasible. And this highlights American traffic and sparseness. - plug-in hybrids have 10-13 mile range which is great for running a few errands (this is only slightly more feasible than in a golf cart or ebikes) - also great for last mile connectivity for mass transit n user…

PHEVs were quoting 20+ miles on electric last decade, I think 25-35 is common now? Actual distance depends on elevation changes and speed/driving, but 15-20 is quite acheivable, as long as you don't make it to highway speeds. And if you go a bit farther and use a splash of gas, no big deal, that's why it has a tank.

25-35 is common, and some like the Prius PHEV can do 45.
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