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A comment on Toyota Is Recycling Old EV Batteries to Help Power Mazda's Production Line. Parent comment

Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by spockz on Wednesday August 27, 2025 @04:17PM (#45044624)
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.

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Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by themafia on Wednesday August 27, 2025 @05:25PM (#45045487)
A relay would allow you to switch it out and then back in again. Which you don't need. Just a fusible link that can be blown to permanently disconnect the battery from the string might be simpler and more ideal for the application.
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Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by londons_explore on Wednesday August 27, 2025 @04:54PM (#45045118)
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.

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Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by carlhjerpe on Wednesday August 27, 2025 @06:55PM (#45046329)
Is the failure mode of whatever chemistry is in an EV that they just conduct electricity? Li-Po usually fail in more spectacular ways than so.
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Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by namibj on Thursday August 28, 2025 @05:11AM (#45050055)
There's NCA (drones), NMC (laptops, phones, many electric cars), LFP (stationary/grid), and LFMP (many new electric cars; slightly more expensive but higher current variant of LFP).
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Re:Toyota Is Recycling Old EV Batteries to Help Power Mazda'... by londons_explore on Thursday August 28, 2025 @04:40PM (#45056799)
Yes, this happens sometimes.

Search this page for "PTC": https://www.electricbike.com/inside-18650-cell/

The PTC protects the rest of the battery if a single cell internally fails short.

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