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 module used a lot at its EOL, thereby making EVs last longer and be viable as cheap used cars even past 10 years like ICE cars are
3) Allow easier upgrades as chemistry improves: solid-state, sodium ion, etc.
Modules could be electrically tested for fit. I'd think the fit range would be quite wide (e.g. if one supported lower max discharge rates than another) given the headroom we have with EVs' power these days: they have far-more-than-needed power (which mostly comes for free with EV range).
The tradeoff is that they'd need to be built to be modular with some standardization on module dimensions (maybe we'll have "ZZ" size like we have AA, C, etc today), and would take a tad more volume in the vehicle (though the limiting factor is weight rather than volume). Easily worthwhile over the current model with a huge monolithic pack.
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.
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.
Balancing multiple battery packs at different wear levels is a huge nightmare. You have to run rebalancing operations all the time and on used packs it can be quite dangerous to trigger a thermal runaway.
If they do it with different types of batteries it is even more complicated, like you need to write some custom software to sync all that up. This is not a trivial project.
If you’re ever in Hiroshima I can recommend a trip to the Mazda museum (Cosmo! 787B!), which includes a factory visit across a raised gantry. It’s free, but you need to book in advance: https://www.mazda.com/en/experience/museum/
What's interesting is that if the batteries are being sourced from JDM cars the batteries are probably relatively young due to the average age of Japanese cars being relatively low (8.7 years) and the amount of yearly mileage is also half for JDM cars when compared to the US. So if you tried the same in the US it may not be as viable.
Looks like this is a PoC for Toyota's "sweep storage system" using "low voltage MOS", which seem to be a fancy invented term for a charge/discharge current limiter. [2] has photos of previous PoC from 2023.
This is not recycling. Recycling implies that you can produce the same product again many times; it's a sustainable practice. This is repurposing or upcycling. It's cool they're getting a second life, but they won't get a 3rd, 4th, Nth life unless the batteries are actually recycled into their component materials at end-of-life. It's kind of like the plastic brick companies: cool that plastic is being turned into a construction material, but it doesn't mean we can stop mining for the primary source material any time soon.
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[ 2.4 ms ] story [ 32.3 ms ] thread1) 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 module used a lot at its EOL, thereby making EVs last longer and be viable as cheap used cars even past 10 years like ICE cars are
3) Allow easier upgrades as chemistry improves: solid-state, sodium ion, etc.
Modules could be electrically tested for fit. I'd think the fit range would be quite wide (e.g. if one supported lower max discharge rates than another) given the headroom we have with EVs' power these days: they have far-more-than-needed power (which mostly comes for free with EV range).
The tradeoff is that they'd need to be built to be modular with some standardization on module dimensions (maybe we'll have "ZZ" size like we have AA, C, etc today), and would take a tad more volume in the vehicle (though the limiting factor is weight rather than volume). Easily worthwhile over the current model with a huge monolithic pack.
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.
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 they do it with different types of batteries it is even more complicated, like you need to write some custom software to sync all that up. This is not a trivial project.
1: https://global.toyota/jp/newsroom/corporate/43207750.html
2: https://www.power-academy.jp/sp/electronics/report/rep03200....