Which part particularly debunks? It appears ambivalent to me. For example, pages 20-21 seem to conclude that "The use of 18650 cells with the same form factor but different internal chemistries creates the risk that a replacement 18650 will have a different internal chemistry from the original 18650, placing individuals and independent repair shops at risk of inadvertently causing thermal runaway events." As a person who already had to flee one structure fire caused by a DIY hoverboard battery, I am sympathetic to this line of argument.
People don't need the right to repair to do stupid things and make stuff go on fire.
But if the hoverboard manufacturer had released the proper specs for their batteries and the safety procedures they undoubtedly provide to their employees and service centers. Then maybe the DIYer would have made something safer.
By keeping safety-critical details like the correct battery chemistry to themselves, they actually encourage people to do stupid things. Getting access to these informations is a big part of the right to repair movement.
Lithium Ion should be replaced ASAP by safer chemistries so we can sidestep this issue completely. As far as I'm concerned this should have never gotten as far as it did and manufacturers that produce crap batteries (of which there are plenty!) should be held responsible.
Apropos: not rare at all to open AAA brand battery packs to find burned out wiring, burned out circuit boards, signs of combustion that somehow didn't go outside of the case. Take no risk with these things, even with the good ones: in case of doubt place in fireproof container and deliver to a recycling station that knows how to handle them safely. If you have no experience with these then do not try to repair a pack because the risks are nothing to be trifled with.
Finally: cheap stuff containing 18650's should be avoided like the plague, if the device is cheap then that means the components are even cheaper. Only use devices that use quality cells, that haven't been recycled and that have only been used within spec.
Your fire insurance policy protects you from monetary loss, but it won't revive you or your companions...
Li-ion is a very big umbrella of battery chemistries, and within can have broadly different safety and stability profiles.
More important is that Li-ion cells are no joke, and are not equivalent to ‘AA’ or ‘AAA’ battery formats. You can NCM, NCA, LFP, Cobalt chemistries and blends within - not even accounting for differing mAH and charge/discharge capacities. 18650 is simply a form factor.
Better labeling, specing, regulated and certified repair processes are just a start for solutions as it is currently a Wild West.
However, statements like ‘Li-ion should be replaced ASAP’ do not factor in that… lithium ion as a platform is not going anywhere and has essentially won at least the next half century for 18650 type form factors and applications. Moving away is not a reasonable solution.
Sorry but that just isn't right. The battery you listed is an just an NMC battery , the listing pages are just lazy and don't list it. There isn't just a plain lithium ion cell. Also lithium polymer just means that a polymer electrolyte is used instead of a liquid electrolyte.
That's pedantic. They're sold that way by the truck load and anybody that buys them for DIY purposes knows that this is how they are designated. People are buying based on the working voltage nominally 3.6V, Lithium Ion chemistry, battery capacity, form factor. Not on the internal details of the battery, which are not normally listed in sales documentation on consumer oriented outlets anyway.
Yes, you can go into the details of the exact chemistry, the packaging, the manufacturers specs and so on but for bulk DIY purposes this is the reality. The detailed chemistry obviously has some implications for safety but because you will have no idea what is in a pack unless you open it (and plenty of times the cells are unmarked) you just have to assume the worst. That's the safest.
> People are buying based on the working voltage nominally 3.6V, Lithium Ion chemistry, battery capacity, form factor. Not on the internal details of the battery, which are not normally listed in sales documentation on consumer oriented outlets anyway.
Lithium Ion chemistry is the internal details of the battery. Which denotes the type of lithium ion battery, there is no generic lithium ion battery. It will fall under a certain category (Ex LFP, NMC, NCA).
Sure you can go buy unmarked cells on ebay but any reputable website should list the battery chemistry on their website or have a link to the datasheet. It is no different than buying any other electronic component.
I've refurbished many packs and built my own, for cameras, e-bikes and laptops. I've yet to find anybody other than myself to be interested in the exact chemistry of the batteries involved. What they're interested in at the highest level is whether it works, and second to that how much it will cost them. I'd be happy to bet that most people that use these batteries would not be able to figure out what exact composition a cell has nor would they care.
It is very clear to me that there is a vast gulf between DIY and professional application, and for the latter I'm 100% sure that everybody there would be able (and should be able) to make the distinction. The number of hobbyists that can do so is going to be very low.
For maximum cringe, have a look at this youtube video and spot the potential problems:
> Lithium Ion should be replaces ASAP by safer chemistries so we can sidestep this issue completely
That would be nice, but so far there are no good candidates that have anywhere near the energy density of Li-based cells. As far as I understand it, besides material degradation and overcharge/overdraw, the energy density itself poses a risk. So even if we had that miracle cell chemistry it would be still pose a fire hazard when subjected to mechanical stress. The stored energy has to go somewhere.
That's true, there are some inherent risks that are hard to mitigate. But those are roughly equivalent to say a gasoline fire or something like that. They are not due to handling the stuff or working on it. Though in fairness: working on an ICE car, especially the fuel supply system is not without risk.
> Lithium Ion should be replaces ASAP by safer chemistries so we can sidestep this issue completely. As far as I'm concerned this should have never gotten as far as it did and manufacturers that produce crap batteries (of which there are plenty!) should be held responsible.
What should they be replaced with? I'm curious to know what alternate chemistry you're proposing for my e-bike battery.
Usually, the safer replacement for Lithium Ion would be LiFePO4. Although I don't know how good performs in e-bikes (I guess it should be fine, as they're used in cars and other stuff...)
It works just fine for that application. But: it is a little bit more expensive for the same capacity, and unfortunately the voltage is a little bit lower so it isn't a drop-in replacement.
Yes, about 50%. So for the same amount of energy you need a larger and heavier battery. Typically the largest capacity Lithium Ion in 18650 format is roughly comparable to a 26650 LIFEPO4. And then there is still the voltage difference (nominally 3.2 for LIFEPO4 and 3.6 for Li-ion).
The 50% or so difference is when both batteries are new. From what I've read Li-ion degrade faster than LiFePO4, so the difference becomes smaller over time (and might even reverse, but I don't have actual data).
> otoh on the weight of the whole bike it isn't a huge problem.
Why do you say this? Non-ebikes can be sub-16 lbs; ebike battery packs can weigh, like, on the order of 50 lbs. Ebike users sometimes need to lift the bikes (up stairs at home, or on/off transit).
Battery pack weight absolutely dominates the design and utility of ebikes; any double-digit percent factor is very relevant (IMO).
A really large e-bike battery is 4kg. Nobody is riding an e-bike with 50 pounds of batteries. Even the battery pack on a Zero FX, an electric motorcycle, is only 42 pounds.
That's because the motors are pretty heavy as well, and once you have that much torque available you'll need a frame and rear hub that can handle it too. My biggest e-bike is about 30Kg including a 2.2 KWh battery. Not quite 75 lb but getting there. The basic machine is a Riese&Mueller charger with a Bosch speed pedelec motor and the usual complement of brakes, gearing and bunch of bags. I don't mind the weight, but I've yet to find someone else that likes that bike. It's a bit of a pain to move around with the motor off but once you're on it and riding it's just like any other bike only more powerful and it lasts for a really long time on a single charge.
I don't know either. I think part of it is that some e-bike customers are not otherwise bike buyers and go for the niche of huge-wheeled quasimotorcycle. I recommend keeping e-bike weight under 50 pounds because it is the design limit of the bike carriers on American buses and on Amtrak. There are plenty of e-bikes under 40 pounds even.
Standardising the batteries so the connector imposes a certain level of safety would seem like a better solution than making it harder to repair. You can also discourage e.g. self made batteries through insurance policies like you do for cars and homes, i.e. you're not covered if you use a non-certified battery.
18650 cells are not like AA alkaline batteries. There are dozens of companies making them around the globe (maybe hundreds), and there are thousands of varieties all with different characteristics.
I've spent a long time in that community, and a golden rule is to never mix cells - even cells of the exact same type because they're often binned to be matched to be even closer in operating capacity. Also, and more relevant here, mixing old and new cells is also a big no no due to changing characteristics during aging and use.
You can't just pop open a battery pack and replace a bad cell. I mean, you can, but if you cause a fire that kills someone, you should go to prison for negligence.
I'm talking about replacing the battery as a whole, currently there are many form factors and you can't be sure you'll be able to get a new battery when the performance of the original one starts to degrade. If manufacturers would be forced to make it replaceable for X years at reasonable cost, either by providing replacements or by adopting an industry standard, that would fulfill the "right to repair" IMO.
You then want to extend that to the other main parts like the motor or the controllers, so you're not left with a piece of junk when one component fails. Just like for normal bikes.
It's not about repairing the battery by amateurs/diy enthusiasts, but the ability to replace the battery with another, compatible. It's not that hard to make sure that new battery meets the required parameters and has compatible connector, so any claim that only one, unique, model of battery can be used is BS. Instead of making stupid excuses producers should clearly specify what are the required parameters and if a battery meets these - should be allowed.
I don't think we should sacrifice the innovation and development of an entire industry on the backs of a tiny vocal niche of people who claim they want to repair their own batteries. If there was some standard form factor the entire last decade of the e-bike industry would never have happened. We'd be stuck with the Yamaha/Bosch/Shimano-style battery pack sitting inside the triangle, and we would not have the superior integrated systems of Trek and Specialized.
This isn't about about repairing batteries (eg replacing individual cells). Almost no one wants to do that, and that isn't the primary problem with reparability when it comes to ebikes. People want to be able to replace the battery, and do other repairs on the system themselves or with non-authorized repair shops, using high quality 3rd-party parts.
Many manufacturers make this difficult or impossible on purpose, and apparently they also have lobbied to change legislation to continue being able to do this, using battery fires as an excuse to cement their parts and repairs monopoly. It's that simple.
Let them innovate where they provide value - in the bike mechanics and drivetrain. But all their batteries are basically the same, built with same li-ion cells from same group of producers. The only innovation here is a proprietary chip making sure you buy only original replacement.
