In this post, we’re going talk about how cordless power tool tabless battery cells work, with the goals of steering you away from a very common misconception and helping you grasp the fundamentals without getting technical.
The most common misconception is that “tabless” batteries involve a modification to the outside of a battery cell.
Shown here is a Fenix 21700 Li-ion battery cell, for use in their flashlights. Do you see that “tab” at the top? A lot of people think this is the bottleneck that is eliminated in tabless battery cells.
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Cylindrical battery cells, such as 18650 or 21700, can have a “button top” or “flat top” positive terminal. This is important, but unrelated to the fundamental differences between “tabbed” vs “tabless” batteries.
I can understand why many people point to the button top of a battery and think that’s the type of tab that’s removed to make batteries tabless, but it’s not.
Movie Theater Analogy
Let’s say we have a movie theater with an arbitrary number of rows and seats. There will usually be an entrance and exit at the back, and emergency exits at the front.
Typically, the audience finds their seats over an extended period of time, even if it’s a full house with every seat taken.
Let’s say there are no credits or after-credits. What happens when the movie ends? Lines quickly form as the exits get crowded.
Now imagine that, as you’re waiting to leave, you’re hungry and tired, and it’s hot and humid. The mood is going to get heated. Any arguments or shoving are going to slow things down further.
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If you’ve ever been on a roller coaster, you might remember how each row of seats will typically have its own gated entrance and either an open or gated exit. The goal is to get passengers loaded and unloaded as quickly as possible to reduce the wait time.
Now what if we apply this concept to the rows of seats in a movie theater, where each row has its own entrance and its own exit.
The movie’s over and people want to leave. Will it be quicker for them to leave through one or two doors at the back, or if each row has its own exit?
Everyone wants to leave as quickly as possible. Will things get as heated when there’s one or two doors at the back, or if each row has its own door at the end?
What Tabless Really Means
Most people will agree that it’s quicker for people to exit a theater when there are a greater number of doors.
How quickly can people exit if the entire walls at both ends of every row have been turned into continuous doorways?
In essence, “tabless” batteries have a continuous “tab.” Instead of single discrete electrodes for positive and negative pathways, you now have continuous pathways.
Visualize the movie theater with open walls at the start and end of every row, similar to the wide entrances where department stores open up into the shopping malls they’re attached to. You’re going to have a quicker path to exit the theater no matter where you are seated.
Let’s say everyone is tired and hungry. With shorter paths to the exit, are things going to get as heated as if there’s just one or two doors at the back?
So what do you get? Faster exiting, less heat.
The entrance and exit paths might still converge into hallways outside of the theater, but the bottlenecking within the theater will be reduced.
That’s essentially how tabless Li-ion battery cells work. It’s not about the tab at the end – the button top on certain cells – but the entrance and exit paths throughout the battery cells.
Let’s go back to typical roller coasters. There’s usually a single line leading to the ride, and a single exit walkway. But the way they open up before and after the seats on the ride, you have a shorter path to enter and exit any row of seats.
Think about trains, buses, or planes. Hypothetically, what happens to loading and unloading speeds if you add a door to every row? Shorter exit paths allow for increased loading and unloading rates, and lower frustrations associated with crowding.
There might still be bottlenecks, but “tabless” battery cell tech is about reducing internal bottlenecks.
Shorter pathways means lower internal resistance in a battery cell. This means you can achieve less heat and greater current flow and power output.
Does that make sense? “Tabless” is about creating shorter pathways inside cylindrical Li-ion battery cells.
We can dive into the more technical explanations in a later post if you’d like.
Bill
“A lot of people that this is the bottleneck….”
Stuart
Thanks, *fixed*!
MM
I always thought a big supermarket or department store makes a good analogy for explaining this. A traditional battery is like Wal-mart having exactly one register open for checkout, while a tabless battery is like them having every register open.
Stuart
That works, too. Or one can visualize a 20 lane highway that narrows to one toll booth off to the side, vs a toll booth for every lane.
will
So what’s more efficient and offers more power,the pouch cells or tabless? Seems like pouches are only in lower AH batteries while tabless are in the larger form factors, is thst because of max power or cost? Id imagine battery style cells tabbed or tabless would be cheaper than pouches.
Stuart
With respect to cordless power tool batteries, you can make pouch cell packs in smaller sizes than with 21700 tabless cell batteries.
At higher pack capacities, 21700 sized tabless cells have a size advantage.
Speaking about Milwaukee M18, their Forge 8Ah and 12Ah batteries have tabless cells for the thermal endurance. You can run the batteries in high demanding tools and applications, pop them on the Cool Cycle Super Charger, and they’re back in use much quicker than with pouch cells.
There could be a cost factor as well, but I don’t see it as a significant factor for professional cordless power tool brands. Cost might be why DIY and consumer-focused brands such as Ryobi and Ridgid launched tabless batteries instead of pouch.
eddiesky
This means… new IMPROVED batteries to sell and replace your “outdated” and slow, overheating batteries! If only we could trade up! 😉
Bill: yeah, too many people, on this rock.
Robert
Stuart, nice analogy. But I could have sworn you already did a technical explanation of tabless batteries. I didn’t find it in the four “Related Posts” links you provided here. Maybe it was a link from someone’s comment.
CMF
For sure once before, but possibly 3 or 4 other times, and always looking for a new analogy.
What is in interesting in the repeated explanations is that the TG followers or more nerdy and should understand this the 1st, or 2nd time for sure.
The companies make all kinds of statements on more this or that. In the end. tabless really address peak demands from the motor. A battery that has “X” number of watts (or watt hours), that is all that the laws of physics or chemistry allow, regardless of battery technology.
Stuart
We’ve had numerous post and comments section discussions about tabless batteries.
But, this isn’t easy tech to understand without extensive background knowledge.
From some of the comments and most notably too many of the social media and influencer “informational” videos I’ve been seeing, it seemed like a good idea to revisit the subject using a different approach.
The latter part of your comment, about batteries having fixed “X number of watts or watt hours” is incorrect. Watts is a measure of power, and watt hours a measure of energy capacity, and both can vary. The entire point of tabless battery technology is to increase the max power output.
CMF
I haven’t seen much by YT or influencers, but I see it possible that they get it wrong or even if right, explain it in a way that will muddy up the waters.
As for my comment, I certainly did not state it clearly. Ohm’s law…volts x amps = watts
A battery that has 120wh, that is the amount, regardless of battery technology. A tabless, pouch, traditional cylindrical cell battery, or anything else that comes out, the tech cannot change the capacity, which is often expressed in wH.
A tool that can pull higher amounts of energy, can take advantage of the lesser bottleneck of tabless, but the battery it self will not last as long (runtime).
Any claim that the batteries last longer would be looking at energy that is not ordinarily lost elsewhere. Example, every battery suffers energy loss to heat. If a tabless battery has less of a bottleneck, under normal conditions the battery could create less heat, which leaves more energy to be actually used and therefore could claim lasts longer. The capacity hasn’t changed, the energy is being used more efficiently. (BTW, I do not follow all the battery tech closely, so I do not know if tabless does not create as much heat, just speculation)
Energy cannot be created or destroyed. It can transform as is often the case in a battery to heat. But the battery tech cannot change the watts or watt/hours a given battery has.
Stuart
Watt’s Law is Power (watts) = Volts (V) * Current (I)
Ohm’s Law describes the relationship between voltage, current, and a component of fixed resistance, with V = I * R.
Watt hours is a measure of stored energy, and what you’re referring to is the max watt hours, which typically decreases with time and charge cycles. However, usable watt hours CAN and WILL vary depending on battery cell technologies and application factors.
Let’s say you have two batteries with the same Watt-hour energy capacity. The battery cell technology absolutely matters in high demand applications. There will be times when a battery with lower watt-hours rating will deliver longer runtime than one with a higher rating.
Yes, energy does not simply disappear, but can be “lost” as heat. Batteries with lower internal resistance will be more efficient, and this is tied to battery technology.
Think if it like 140 calories from fruit vs 140 Calories from a Twinkie. Which is going to fuel you for longer? Calories, like watt-hours, are a measure of energy. Junk food will usually provide an energy spike, while fruit will usually provide sustained energy.
Max watt hours is one characteristic, delivered watt hours is another, with the latter highly dependent on factors dependent on battery technology and engineering.
While the max rating is important, we’re more concerned with how much work can be done with a tool and battery, and that’s where battery technologies heavily contribute to significant differences.
It’s like 2000 Calories from junk food vs 2000 Calories from well-balanced means and snacks. Sure, 2000 Calories = 2000 Calories on paper, but the results will be very different.
MM
To add to what Stuart wrote, I understand where this confusion comes from; it was sort of an “ah-ha” moment when I first learned this.
When we (consumers) talk about batteries we usually only talk about two or maybe three things: the voltage, the current capacity (amp-hours), and sometimes the peak power they can provide. Because these are the factors we are constantly talking about we learn that is all there is to batteries. However, reality is a lot more complicated, and that rarely gets discussed outside of electrical engineering circles.
When we learn about electricity in school and solve simple circuit diagrams we ignore all of this complexity (at first) to keep the lesson introductory. But in reality a battery is not a theoretically ideal voltage source, it has internal resistance, inductance, and its voltage/current behavior is a curve rather than linear. Temperature also affects the discharge curve of the battery.
If we want to explain tabless batteries in electrical engineering terms we can: the “tabless” design means the cells have lower internal resistance and lower inductance.
CMF
Well, looks like I am wrong.
Stuart
@CMF, not completely. If it makes you feel better, I get plenty wrong too. I’ve made inferences before, and they were wrong because I didn’t know what I didn’t know.
You have 2 bowling balls without the holes drilled, B1 and B2. Both have the same size, shape, and surface finish. From even close up, balls B1 and B2 look identical. B1 weighs 10 lbs and B2 weighs 20 lbs.
You stand on top of a 20,000 foot platform and drop both balls. Which one contacts the ground first, and why?
Most people will get this question right, but their explanation will be wrong, or they’ll get it wrong but their inference will be correct but in incomplete. Some people will get it right and their reasoning will be accurate.
I get things wrong all the time, and that’s how I learn best.
Rich Shew
Tabless is fine, but the real bottleneck is cylindrical cells. Pouch or stacked cells use space much more efficiently and don’t necessarily need to have tabs either.
Jared
From Stuart’s other posts, it seems like cylindrical cells are only the bottleneck on small battery packs. As they grow in size, the advantage of pouch cells seems to decrease relative to tabless cylindrical cells.
From what I remember, the reason for that primarily relates to heat build-up and dissipation – but there may be other reasons.
It seems like cylindrical tabless cells are likely far more abundant and cost-effective because of their use in other industries. One reason may just be that there’s no need to make a specific size of pouch cell when you can simply use an off-the-shelf option – plus that way you can more easily switch cells when new tech comes out (think of how 18650s or 21700s have increased in both capacity and discharge rate over the last decade).
If you can achieve the same or better performance with tabless cells without increasing the overall pack size – why insist on using tabless for larger packs?
Stuart
Pouch cells also have tabs, but the paths are short. Pouch cells are flat whereas cylindrical cells have long flat strips that are rolled together into a cylindrical shape.
Without getting into specifics, while pouch cells could be engineered to have an advantage, tables cell batteries are looking to be the better choice for higher power and higher capacity cordless power tool applications.
The stacking of pouch cells within a battery pack in more space-efficient, but cylindrical cell arrays have better thermal dissipation.
Rich Shew
Given that pouch cells are the dominant form in cell phones, it is reasonable to conclude they will receive the bulk of R&D. The phone industry dwarves the cordless tool industry and virtually every rechargeable battery advancement has come from that sector. It may well be true that cylindrical cells cool better in large applications, but it’s also inevitable that those battery packs shrink with advancements in battery chemistry.
Stuart
I see where you’re coming from, but cell phone batteries are very different in too many ways to draw parallels to power tool batteries.
Cylindrical cell battery development and innovations are fueled by the electric vehicle (EV) battery industry. A cell phone has one battery, an EV has thousands.
At this time, tabless cordless power tool battery packs are superior to pouch cell battery packs in applications that require high power and long runtime.
MM
Cell phones no doubt drive battery R&D, but their design goals don’t necessarily cross over to power tools. Cell phones don’t have very high current demands but that is very important for tools.
In my opinion the electric vehicle market is what drives the most relevant battery improvements for power tools because it’s both a huge market, and one that shares more of the same design goals & concerns.
JR Ramos
Precisely that. Development has been wildly driven by electric vehicles (cars, not bikes) and is just about the only reason we have seen the advances and further refinement and experimentation with li-ion over the last 7-8 years. The rest is just trickle-down benefit for other niches.
JR Ramos
In addition to all said above, the differences between paste/cylindrical li-ion cells and gel li-po cells has some other nuances beyond just resistance/bottleneck and resulting heat. The cylindrical design has just been a carryover from the earliest battery cells so that’s what they went with. They learned how to pack them tighter and use better anode and cathode materials and more reactive magic soup mixes, so the next logical step was increasing that surface area of contact to reduce resistance further. Li-po gets around that in other ways but as said, of course there are still tabs/connections to design and work around. One of the biggest differences is really the convenience of form factor with pouches, which, among all the other things, makes these wildly thin phones possible (it really is amazing how thin they are and how much they can DO, isn’t it?).
So the bottleneck, so to speak, with round cells could probably be even better than tabless, in a still-round package, but it would take a big redesign effort. Tabless was a logical step once they started to focus on that aspect as platforms matured. I don’t know how much further they can go with either round or li-po packs at this point but at least we’ve seen some significant improvements in a relatively short period of time! There will still be tradeoffs in various aspects even as each improves but it doesn’t necessarily mean one is better than the other. Our high-drain applications are where the choice gets difficult and you have to choose what’s most important.
Kilroy
Very interesting and easy to follow analogies. Thanks.
To take your train/plane/roller coaster analogy a bit further, I would point out that vehicles where actual time in motion is relatively short (such as roller coasters, airport shuttle trains, and to a lesser extent subway cars, but not long distance planes) tend to have far more & larger doors for speedier movement of people. That improves overall throughput of passengers, as it’s worth making sacrifices to speed boarding & deboarding when the actual journey time is relatively short. In contrast, the difference between a 40 minute boarding and a 60 minute boarding time for a 12 hour flight on a long haul widebody plane isn’t as significant.
Does that extension of the analogy also apply to tools? For example, am I correct in assuming that tools with high power needs would benefit more from tabless batteries than tools with low power draw requirements?
In non-tool terms, I don’t think I’d see a huge performance difference in a high end AA battery in my remote control vs a generic one (even if the higher end battery were more efficient or lasted a little longer), but I probably would see a difference between the two battery types in an expensive flashlight.
Jared
Torque Test Channel has some videos showing the impact pouch and tabless cells have on certain tools. It’s interesting.
Some tools benefit a LOT from the increased discharge rate, others have little or no impact. It depends on how much power the tool is capable of drawing – i.e. whether the tool or the battery is the bottleneck.
Also consider that it depends what you’re comparing it to. E.g. the 1.7ah Powerstack versus a compact 2.0ah is often a pretty big jump. The 1.7ah Powerstack though, is still a decrease compared to the 8ah battery or the 9ah Flexvolt pack.
The world may not really get wild until we see REALLY large tabless packs, but the 8ah Powerpack is already pretty spicy.
The recent testing with Bosch’s tabless pack though, was pretty disappointing, so not all tabless packs are created equal either.
Ken
Read the pinned comment on the recent TTC tabless video. They incorrectly stated they tested a Bosch tabless battery when in fact they just tested a regular US-market battery (non-tabless). I put the blame on Bosch for still not having tabless batteries available in the US market. Actually, I hope the TTC video puts some pressure on Bosch to get their crap together and send the tabless batteries our way.
Jared
Well that makes more sense! Thanks
Stuart
Yes, tabless batteries will generally deliver greater benefits when used to power more demanding tools. There is unlikely to be any advantages with lower demand tools and equipment, such as a radio.
Your AA battery and TV remote analogy works well.
GaryVA
I’ve had luck repairing individual cells in my current battery packs. So when my current pack with tabbed cells goes belly-up, can I replace all the cells with tabless cells? Or are there other issues with tabbed to tabless cell substitution?
Stuart
It’s extremely advised against.
Generally, battery cells should be matched to each other, and this is especially true for Li-ion cells.
You absolutely should not replace individual tabbed cells with tabless cells, even if you could.
Dave
The rest of the battery components may not be rated for the additional current flow of tabless cells, everything works as a system and is tested as such.
GaryVA
That’s not what I meant. Sorry. The key words in my question is “replace ALL the cells”. I know I can replace individual cells tabbed for tabbed or tabless for tabless. I would never try to replace one tabbed cell for a tabless in an otherwise tabbed cell pack. I say this due to the unknown (at least to me) tabless cell architecture. My best guess is that the battery pack processor needs a firmware update for the tabless chemistry. I was only wondering if anyone out in ToolGuyd land knew more about the electronics and chemical end of tabless cells. My hope is that there is no significant difference other than the physical replacement of the tabs for the tabless end caps.
So my question was whether I can turn a tabbed battery carcass into a tabless by removing all the tabbed batteries and replacing them with tabless. That would result in a replacement cost of around $40-50 vs whatever the new tabbed batteries will cost (which I assume will be very, very high). What I was referring to is whether the electronics of the tabbed battery carcass (sans batteries) will accept the tabless cells and whether the tabbed battery charger will correctly charge the tabless battery pack. I could likely make my own determination if I had the schematics and design papers for the battery pack and charger. But I presume that may be a question only the design team at Milwaukee engineering can answer and I highly doubt they will…
JR Ramos
The cells themselves are really no different on the outside so yes, you can do a direct swap there. Of course you must consider current and will want to upgrade the strips to something a little thicker and perhaps copper (Bosch’s preference) – and from what I’ve seen they are preferring either a special spot weld or a six-point spot weld with these over the usual 2- and 4-spot welds. Assuming you have a spot welder – you have to use one. No soldering, don’t even consider that for a minute. Soldering is generally a bad idea with OEM lithium cells anyway (can get away with it on the positive end sometimes) but with high current you absolutely need to weld the strips (and properly).
Offhand I can’t see any reason it would be a problem with most tools. Talking Milwaukee, the controls are in the tools themselves, not the pack, so unless there’s a governing limit there that will prevent tabless from delivering what it can, you should be good to go. We already know that some tools just do not see benefit from higher current, but many do and it’s impressive. The other thing to consider is thermal sensors and cutoffs. Higher current will give higher heat even with the lower resistance of tabless cells. I *think* the thermistors they use on the packs now would be fine because you don’t want to elevate past those temps anyway, regardless of cell choice. As for charging, it’d be fine. They do the typical voltage approach and don’t really fully charge them anyway….and neither is smart enough to know who or what the other one is anyway. The limitation there would be that you wouldn’t be able to charge the tabless cells as fast as they are capable of being charged (without harm) but I don’t think any of the current chargers are really taking advantage of that anyway. Slower charging is still always better for cell health and lifespan even if the cell can handle more abuse in a healthy way.
The pack-to-tool connection is a weak point and some of these tools frankly should be using beefier contacts with a better connection, but I don’t think the tabless packs are going to deliver so much more that they should risk overheating or burning contacts and the supply wires in all the tools I’ve seen should also still be fine. Rotary hammers under long periods of use, angle grinders, mixers, and maybe miter saws are the ones where I would want to be sure the wires are still sufficient.
You might reach out to the guys at Torque Test Channel and Tool Scientist to get their take or see if they have any helpful advice to offer before you start. Probably a lot of other experiences shared on various reddit subs and battery/e-bike/powerwall forums where people are constantly tinkering and modding and experimenting. Also, from what I’ve seen the cost of the Ampace tabless cells isn’t all that much more than decent Samsung and Molicell standard cells…problem right now is finding them in stock…and pricing/availability may get pretty bad soon given the temperature of the world stage.
JR Ramos
I said “benefit from higher current” up there, but the biggest benefit that these lower resistance tabless cells give (and pouch cells) is less voltage drop. So your 19-17 volts doesn’t sag down to 15 resulting in severe loss of performance. Higher current helps, too, but it’s the voltage maintenance that is the real shining star here.
Stuart
@Gary, I’d still heavily advise against doing so.
@JR Ramos, I have only seen the inside of Milwaukee M18 Forge batteries, and they laser-weld all of the connections.
JR Ramos
Power regulation is not in the battery pack with Milwaukee. In fact their onboard circuitry is really not much at all. Ridiculous in 2025.
Stuart
There’s still a handshake. It used to be that drills delivered higher power when paired with higher capacity batteries instead of compact. That was more than 10 years ago and the electronics have gotten much more complex. Nearly every brand has claimed instantaneous performance boosts with existing tools. There’s never any fine print, suggesting you get higher application speeds and similar right out of the gate. It seems that an older battery with tabless cells swapped in likely won’t be recognized in the same way as a tabless battery with newer BMS.
Battery manufacturers, consumer protection agencies, safety groups, and other battery authorities strongly recommend against handling loose cells, let alone home battery building or repair. It’s dangerous and risky, even for those who know exactly what they’re doing – which most people don’t.
That said, I don’t think it’s a good idea for one – who is experienced and capable of doing so safely – to swap tabbed cells for tabless. I’m not convinced there will be benefits IF one could even source tabless cells for reasonable pricing.