For the cautious, a good piece of advice is to always wait to buy a new product until after the first model year, whether its cars or consumer electronics or any other major purchase. This gives the manufacturer a year to iron out the kinks and get everything ship shape the second time around. But not everyone is willing to wait on new tech. [Berto] has been interested in lithium capacitors, a fairly new type of super capacitor, and being unwilling to wait on support circuitry schematics to magically show up on the Internet he set about making his own.
The circuit he’s building here is a solar charger for the super capacitor. Being a fairly small device there’s not a lot of current, voltage, or energy, but these are different enough from other types of energy storage devices that it was worth taking a close look and designing something custom. An HT7533 is used for voltage regulation with a Schottky diode preventing return current to the solar cell, and a DW01 circuit is used to make sure that the capacitor doesn’t overcharge.
While the DW01 is made specifically for lithium ion batteries, [Berto] found that it was fairly suitable for this new type of capacitor as well. The capacitor itself is suited for many low-power, embedded applications where a battery might add complexity. Capacitors like this can charge much more rapidly and behave generally more linearly than their chemical cousins, and they aren’t limited to small applications either. For example, this RC plane was converted to run with super capacitors.
I had a product I was building that required backup power for some time to ensure the product was safe. The caveat was we couldn’t have any sort of stored energy after 20 minutes or so. I did lots of prototyping with super capacitors and spent way too much time with the misleading “Lithium Capacitor”. The only clue you get that it’s a battery is theres a minimum voltage. For my case this wouldn’t work but it looked like I had found everything I was looking for for a brief moment. Very frustrating.
I was very surprised to learn this too. Apparently this is called a “hybrid capacitor”.
The Wikipedia article on LICs says “In conclusion, the LIC will probably never reach the energy density of a lithium-ion battery and never reach the combined cycle life and power density of a supercapacitor. Therefore, it should be seen as a separate technology with its own uses and applications”.
To me, that means that it shouldn’t be called a “capacitor” any more than it should be called a “battery”. I’d like to propose a different name. Since “cattery” is already taken, I suggest “battacitor”. I know this may sound a bit funny, but I’m completely serious in my contention that these devices should NOT be called capacitors.
No cap. Lit. Litacitor.
“No cap. Lit. Litacitor.”
Until the cheaper sodium-based version starts to gain traction, or some other battery technology is paired with super-caps…
Perhaps material-specific names should be avoided.
A term used by Phillip Jose Farmer in his novel Riverworld many years ago.
Thanks! I’ve read a fair amount of SF but not much Farmer, so I hadn’t heard of it before. I used a double ‘t’ and he didn’t; nevertheless, it’s a cool coincidence. I’m definitely going to start calling these “batacitors”.
We called them Capatteries at work lmao.
My vote goes to “battery and capacitor”. Why confuddle it into something else?
The Wikipedia article on LICs says “In conclusion, the LIC will probably never reach the energy density of a lithium-ion battery and never reach the combined cycle life and power density of a supercapacitor. Therefore, it should be seen as a separate technology with its own uses and applications”.
To me, that means that it shouldn’t be called a “capacitor” any more than it should be called a “battery”. I’d like to propose a different name. Since “cattery” is already taken, I suggest “battacitor”. I know this may sound a bit funny, but I’m completely serious in my contention that these devices should NOT be called capacitors.
These are marketed as being the best of both worlds, but so far in my experience they are the worst of both worlds. Maybe I just haven’t been able to think of a use case.
Agreed. A few of these have made it into student projects over the last two years. They were put on my school’s banned materials list after two fires (one in a classroom and another in a student’s backpack). They simply can’t take the abuse of regular capacitors. The capacity was also disappointing compared to regular lithium batteries with proper charge controllers.
When you can’t think of an application, think single use vapes and single use chargers. They might also be good for raid on card ups and volatile memory timers.
A use case where I see this used is circuits that run on low power and use a low current power source (e.g. bobbin type LiSOCL2) and sometimes need to deliver a peak current higher than the power source can deliver, for example: do a measurement, transmit data. You can use a spiral type LiSOCL with a lower energy density or add a supercapacitor or LiC. A LiC has a lower leakage current than a supercapacitor, making it a better choice than a supercapacitor for this use-case.
” But not everyone is willing to wait on new tech. ”
Just think of all the things denied if we had waited for, “the other person…” before doing anything. Pioneers indeed get all the arrows, and the wait-and-see get the land.
What about and when are we going to get the graphene super capacitor?!?
In about 10 years, but by then we’ll have Mr. Fusion and won’t need graphene super capacitors.
I’ve used hybrid capacitor and NiMH capacitors in the past from Varta. Charging characteristics of a capacitor but can sustain voltage like a battery. Measured in farads such as 90F 4.2V. They are coin cell shaped with wider temp range than typical NiMH but not as much as regular caps. Smaller size than battery cells but more expensive. Another down side is self discharge could occur over a few days. But good for emergency backup for a few hours of cellular radio for example. They are called HVC
A lot of these are literally just ordinary lithium cells in capacitor cans. See Big Clive’s excellent video:
https://www.youtube.com/watch?v=Vl5eOZ-VNnQ
LiC (a kind of hybrid supercapacitor) and Li-ion cells may have similar construction in parts they aren’t exactly the same. And the Big Clive video you linked shows an ordinary Li-ion cell packaged in a can like a capacitor but (mostly) labeled properly.
The advantage of a LiC over what Big Clive pulled apart is that they’re a little safer and less apt to burst into flames. And much better charge life cycle performance compared to a Li-ion cell. But they’re more expensive and don’t hold as much of a charge.
well, i am curious what chemicals leaking out of this thing after 10 or 20 years will do to the pcb is is soldered on.
I love hybrid capacitors, they are ideal for outdoor applications where a li-ion battery would fail in the cold and wear out after 500 charge and discharge cycles. Compared to Lithium Ion batteries, Lithium Ion Capacitors have almost endless charging cycles, they don’t have shipping restrictions, they don’t need to be disposed with chemical waste, they don’t need protection circuits to prevent dangerous situations. Compared to supercaps they have 6 times higher energy density, a much more usable voltage range, and they have 5 times less self discharge. Therefore it is a very durable, green storage unit with long life.
I love Berto’s idea. The solar energy harvesting circuit he proposes is actually very smart. When a 5V solar panel is combined with a 4.0V LDO and a schottky diode the LIC is charged to exactly 3.8V. The solar panel will work close to it maximum power voltage and the power loss is very small due to the low voltage drop from the LDO and schottky diode. This way you can make cheap and very efficient energy harvesting circuit. Compare that to a switched mode energy harvester and you will save dollars. I have designed such a circuit for Voltaic Systems. https://voltaicsystems.com/LIC-solar-charger/