Charge your mobile phone or electric car in a few minutes, which sounds attractive. Supercapacitor technology has the potential to provide the kind of performance that batteries cannot currently provide. Although batteries are constantly improving, the speed of development is not very fast. Please keep in mind your old Nokia phones with Ni-Cd batteries and how many days you used them before needing to be recharged. Today, we have lithium-ion batteries, and we have to charge our mobile phones every day. There is clearly a need for better energy storage options, and supercapacitors seem to be the only technology that comes close to replacing batteries.

The battery stores energy in an electrochemical form, and the internal reaction of the battery releases to form an electric carrier that can be used for current. Supercapacitors work very differently. They store energy in an electric field. When charges with opposite signs are separated from each other, an electric field is created.

The operation of an ordinary capacitor is shown in the left figure. The two conductive plates are separated from each other by a dielectric. When a voltage is applied to the board, electrons accumulate on one board and are depleted from the other board (positive holes are formed). This charge separation creates an electric field in the dielectric, and this electric field is where the energy is stored. Once the magnetic field reaches its maximum strength, the capacitor is fully charged. Electrons are attracted by holes, so if we provide them with a flow path, current will build up and the capacitor will start to discharge.

Supercapacitors have different designs, as shown in the picture on the right. We also have two electrodes usually made of carbon, an electrolyte, and a diaphragm that allows the transfer of ions in the electrolyte. When a voltage is applied to the electrodes, positive ions diffuse to the negative electrode, and negative ions diffuse to the positive electrode. The charge accumulates on the surface of each electrode to form a double layer (hence the name electric double layer capacitor). Each double layer works as a simple capacitor that we explained before, but we have one on each electrode. Therefore, the super capacitor is actually two capacitors connected in series in design.

But why is the capacitance in supercapacitors so large compared to ordinary capacitors? The capacitance (proportional to the energy that can be stored) is proportional to the area of ​​the plate and inversely proportional to the distance between the plates. In ordinary capacitors, the distance between the plates is the thickness of the dielectric-about tens of microns, while in supercapacitors, the distance is on the order of nanometers (thousandths of a micron). In addition, the carbon technology used for supercapacitor electrodes allows for a larger surface area. Its sponge nature makes its effective area 100,000 times larger than the square area of ​​the electrode itself.

Now batteries and supercapacitors are complementary, and the advantage of one is the weakness of the other. Let us review the key parameters of supercapacitors and lithium-ion batteries:

Compared with batteries, supercapacitors have an additional disadvantage: their voltage drops approximately linearly with the stored charge, while batteries maintain an approximately constant voltage until they are almost exhausted. This means that extra circuitry is required to keep the voltage at a usable level when using supercapacitors, which consumes some energy in the process. The typical voltage of a supercapacitor is 2.5V-2.7V. Like batteries, you can connect them in series to obtain a higher voltage. However, the capacitance and ESR (Equivalent Series Resistance) difference between a single supercapacitor is small, which causes uneven voltage distribution. Overvoltage on the supercapacitors will quickly lead to failure, so a balanced circuit is required to ensure that the voltage on each supercapacitor is approximately the same.

Li-ion technology has safety issues that we have all heard about. The recent Samsung Galaxy Note 7 accident and the Boeing 787 Dreamliner that was grounded due to battery fire in 2013 are just two examples. Of course, considering that there are millions of batteries, the actual failure rate is very low, so it is not an unsafe technology. Regarding supercapacitors, their internal resistance is much lower than that of batteries, so in the event of a short circuit, they will not generate heat. Of course, this technology is still under development, and new materials and new methods that can bring higher capacity may also increase risks, but as of today, we can say that supercapacitors are safer than lithium-ion batteries.

Supercapacitors already have several niche applications, with an estimated global market of 400 million U.S. dollars. Memory backup and protection is one of the earliest applications and is also used to power electronic toys. They are also used in solar cell arrays and miniature energy harvesting systems. At the high end of the energy storage spectrum, supercapacitors are used in hybrid electric vehicles for regenerative braking and to provide starting power. The power grid can also benefit from this. Using super capacitor banks as surge buffers, transmission lines can operate at close to 100% of the capacity, thereby improving efficiency.

All of this is good news. Supercapacitors have begun to play some of the roles traditionally assigned to batteries. But supercapacitors still lag behind batteries in terms of storage. New advances in technology, such as the use of graphene and other compounds, may increase capacity in the near future, making supercapacitors a real alternative to batteries. Currently, manufacturing is still expensive, and the physical size means that even if you are willing to spend a lot of money on the price, you still cannot provide a reasonable alternative to today's lithium-ion mobile phones. Perhaps the next trend for smartphones will be a return to brick design to make room for supercapacitors to take advantage of their fast charging and long service life. Until then, we are waiting for manufacturing advances to be able to fit larger plates into smaller spaces.

Don't forget that supercapacitor battery hybrid vehicles are doing some interesting work, and these hybrid vehicles have some of the functions of both.

"Will supercapacitors replace batteries?"

No; never. Batteries actively generate energy; supercapacitors can only store energy passively. The main difference.

Interestingly, I always thought that through chemical reactions, they would release energy.

As you probably know now. The battery uses a chemical reaction...which acts as a cap. do not want.

Unless you have a nuclear battery, it will not "produce" energy. It only releases the energy stored in chemical bonds. Therefore, batteries, like capacitors, can only store energy without generating energy. It is just stored in a different way.

The same is true for fossil fuels. Fossil fuels are just a reservoir of life energy that existed millions of years ago, and store energy from the sun through photosynthesis. Therefore, when you drive a gasoline-burning car, you are actually driving a solar car. It is just a more indirect "solar power supply".

Well, to be fair, even cell phones powered by nuclear decay have to be charged, and it is generally thought that a supernova or breeder reactor heart is required to be fully charged.

Except for coal, there are no organic components in the oil and natural gas produced by the fuels we use.

Can you explain it? Organic: "Related to or derived from organisms."

What do you call C in carbon dioxide, inorganic?

The statement about battery active power generation is contrary to the facts. I don't even understand how you could be so wrong? If you leave the battery alone on the shelf, do you think it will charge itself?

The term "battery" refers to storing rather than generating energy. Where did you learn that the battery is a generator?

"Battery" refers to quantity. The "battery pack" is like the "cannon battery".

The lead-acid car battery contains ten batteries. A 9-volt battery contains 6 batteries.

A primary battery (alkaline battery, zinc-air battery, to name a few) generates electricity through a chemical reaction. It will never be charged. The chemicals will eventually be exhausted and then discarded.

These are old, specific, and easy-to-understand terms.

But they are so commonly misused that they are now equivalent terms for all intents and purposes.

To some extent, defending the "true" definition of a battery is just an example of etymological fallacy. You can sit there all day and pretend "decimate" means "decimate by one tenth"

I don’t know your particular type of car, but a normal car battery has 12V and contains 6 batteries, each with 2V.

@HC Thank you! Engineering and related fields require a certain degree of precision, which will cause some people to forget (or attract some people who have never learned) the use of language-including connotation, extension, grammar, etc.-can only be right or wrong Consensus within a specific group. The original equipment manufacturer is not handed down by God, and even this does not prevent me from following different gods. :)

Lead-acid batteries produce 2.2 volts per battery. (6 grids)

You cannot produce energy, at least there is no nuclear reaction.

Nuclear reactions do not produce energy. They convert matter into its energy equivalent. Where does "substance" come from? Well, this is too cosmic for me.

The first law of thermodynamics is a version of the law of conservation of energy, applicable to thermodynamic systems. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but it cannot be created or destroyed.

I learned a long time ago to never say never, but when you look at the comparative energy available between 1 farad charged to 4V and 1 ampere hour charged to 4V, it highlights the difference. 1 joule = 1 watt * 1 second, 1F capacitor is 8 joules (1/2CV^2), 1A 4V small battery is 14400 joules (assuming that the discharge voltage of the battery discharged at 1C is completely flat...).

Undoubtedly, the capacity of supercapacitor technology needs a breakthrough of 4 orders of magnitude to be comparable to today's lithium batteries. This breakthrough (or series of breakthroughs) may eventually come, but batteries are constantly improving, and some advancements apply to both technologies. In addition, breakthroughs in power consumption are also taking place, such as sub-threshold logic, which can reduce the requirements to the point where supercapacitors are "good enough" for most applications.

Of course, this will depend on the application. In high-cycle services such as regenerative braking, they may beat batteries, and may be in certain grid services, but never where long-term on-demand performance is required.

Agree, better. Considering the capacity of # charge/discharge cycles and charge/discharge rate in the life cycle of the device, there are many upper limits on the battery, but comparing the energy density and the joule per unit volume, the battery will continue to win for a long time in the future.

I agree that in "large" applications (off-grid storage, car start-up batteries, and to a lesser extent, electric vehicles), some of the advantages of supercapacitors may be useful, that is, they have a longer life and are assumed to be off. Open/charge.

Will we see them in personal consumer products such as mobile phones? Possible, but only if they make them safe and economies of scale make them cheaper than current chemical batteries, because whoever really needs can be fully charged in one minute (when your charger is the limiting factor) or can dump the whole Does the battery of the mobile phone charge in one second, or will it last for 10 years?

Absolutely correct, this is the real reason why capacitors cannot replace batteries, at least not in the near future. Without "generating" energy, it is impossible in reality.

The battery does not produce energy. It is just storage. It's like a super capacitor. The difference is the energy density. Therefore, compared with similar lithium batteries, supercapacitors need to be larger and heavier. In addition, the price.

It depends on what battery you are talking about. Today, I took the Nice Tram No. 2 to the airport, a new regular service through Nice, France. Tram2-Yesterday was the first public operation-without batteries, cables or electrical lines, it travels at 70 kilometers per hour on some tracks. Electricity is provided by solar energy to the super capacitor pads of the station, which can provide enough electric power for the tram capacitors to reach the next station within 2 seconds. Smooth, clean and fast. Very cheap for the public, 1 Euro per ride! I heard that this is the world's first. Tram 1 in Nice-used for 10 years or more-uses batteries that are charged via cables at the station. Look! Super capacitors replace batteries!

Bugger, I thought about this idea for a while, and I am glad that someone is finally working on it. For 1 Euro per trip, they will quickly recover the cost because operating costs are reduced or electricity is eliminated, the initial cost per kilometer is cheaper, and there is no copper in overhead wires or pillars. Many good ideas from all over the world need to be spread all over the world.

Thank you for finding the information about super capital letters interesting and useful.

I just completed a design with a super capacitor to support the power supply of an industrial embedded Linux system. Electric double-layer supercapacitors have extremely low internal resistance and can provide tens of amperes of current when short-circuited. This is a safety consideration similar to that of high-discharge lithium polymer batteries.

You put forward a very effective point: as the energy density of these two storage devices increases, the possibility of sudden accidental discharges causing major injuries will increase. I’m not sure if I often use something that not only looks like a dynamite stick but also explodes like a dynamite.

The cover can be short-circuited without damaging the cover. The concern is what happens to the bears.

For the time being, once these things start to store a really large amount of energy, how they fail if they are crushed will be a problem. In any case, whenever someone sells a large amount of potential energy, the danger increases.

@ Ostracus-Generally speaking, so far, atomic batteries have been very low-power devices, and any risks they may bring come from the loss of containers and the release of radioisotopes. But even so, the number is very small and the harm is quite limited.

Well, the ones I think of are more like fiction. Unless some amazing engineering feats are about to occur, I don't think atomic batteries will be a problem, and glass encapsulation of fuel leakage will not be a big problem.

I am not a formal engineer, but I have always liked this topic.

Instead of having a large supercapacitor, how about connecting them in parallel? To further eliminate risks, they are only mechanically connected in parallel when needed for automation. I understand that in this process, it may still be short. But at least when not in use, the capacitors are segmented. If one is short-circuited, only one will be affected.

Now I have the vision of a portable 12V spot welder.

Just charge the capacitor, then *BANG*.

You can do this with a large regular cap. Use a screwdriver to discharge once and solder to the terminal. Explained something to the owner of the hat...

There are many plans for capacitor discharge welding machines, and they are also commercially available, which is the Sparky series of jewelry welding devices. For example, they can weld stainless steel studs to the back of gold earrings, one of their advantages. They are usually used to solder the lugs on the battery pack because they do not significantly heat the battery during the soldering process. I am not building 12V: it raises the wall voltage to about 400V and then rectifies it to charge the capacitor. But you can easily do this with 12V.

The lid may survive, the short circuit will not

Sorry, I accidentally clicked "Report Comment".

I have seen a wrench melt due to an accidental short circuit of a lead-acid battery. So I don’t think the supercapacitor will be damaged when a short circuit occurs, but the tool or wire that causes it...

I am more concerned about what might happen if the fully charged supercapacitor is physically damaged

Star Trek shows us what can happen.

What if this is inside the capacitor?

This danger applies to any capacitor that is large enough. I remember someone told me that huge capacitors used in military radars must have a crossbar between the terminals to prevent them from absorbing lethal charges from the atmosphere. This will start 40 or 50 years ago, long before the "super" cap.

Thirty years ago, when our large high-voltage (polychlorinated bisphenol-filled) capacitors were not in the circuit, we would short-circuit their terminals with a small wire. Large, about 7 inches thick, 2.5 x 3 feet.

interesting. A house *driven* by the atmosphere.

Although atmospheric electricity (*) is possible, these covers will not charge "from the atmosphere." The captured charge is slowly released from the dielectric ("dielectric absorption"), which can reach lethal levels under appropriate circumstances. *) I have seen it before: short-wave amateur radio "long-wire" antennas (40m band?) during snowfall (very dry air) with RG213 coaxial cables and N-type connectors that are tens of meters long, at about 3-4mm Within the range of about 1/second, jumping sparks are generated in the connector, and the Teflon dielectric in the connector explodes and discolors quite a lot.

Under daily conditions, it is not uncommon to have electric fields of several hundred volts per meter. Only the charging current is very small.

Nonetheless, 10 joules are still enough to stop your heart or make you hit yourself in the face due to an electric shock. If you have a current of 1 nanoampere and a voltage of 1000 volts—assuming that one end of your capacitor is grounded and a wire is suspended in the air—it can be left there for three months to obtain a charge of 10 joules.

@Dax: The current I calculated is far more than 1nA: 50Ohm coaxial cable has 100pF/m, assuming that the breakdown voltage of 20m -> 2nF dry air is as high as 20kV/cm, and assuming that the breakdown voltage at the connector is 5kV. This provides us with 10µC of charge for each spark, and depending on the discharge rate (between 1/s and 10 seconds), the current is 1µA to 10µA, which is much larger than 1 nA.

Those huge capacitors are still microfarads. However, they may be high voltages. As mentioned earlier, when trapped electrons migrate, they will not be charged. If even a small part of the charge remains on the high-voltage capacitor, it will generate an uncomfortable high voltage and become an accidental spark source, which is also a firearm.

http://physics.stackexchange.com/questions/263790/main-cause-of-self-charge-of-unshorted-capacitors

This is from Bob Pease

http://www.datasheetarchive.com/files/national/htm/nsc03883.htm

When I built the capacitor discharge welding machine, I used a set of 630V, 2200uF capacitors. The man who gave me his hat hideout soldered megohm resistors to the terminals because he said they would "bite" if he didn't do this. I ended up doing something vague like a three-state device, so when the cap welder is not in use, all caps are short-circuited with similar resistors, and then the relay enters the "charged" or "discharged" state during use.

Many months ago, I used to work in the electronics industry, doing maintenance work. This was in the late 70s. We got a bunch of these big boards, about 2×2 feet, just pasted with TTL, most of them have Vcc to ground shunts, but they used to work at some point in time. People giggled with them, but in reality it was just shots most of the time. One night, I was looking around in the warehouse and found a bunch of interesting things. One is a very large bucket of calculation level upper limit. 5V is about 200,000uf. These are the size of a mason jar with large screw terminals. I still remember seeing it once and I thought it would be a neat paperweight. This is an SCR, but the rated current is hundreds of amperes. One of the terminals is a braid, which is heavier than the wire connecting the car's starter. A few days later, I completed my device. A bucket lid and a large SCR and a push button switch. You connect the lid to the workbench power supply, and then slowly increase the voltage to approximately 4 and a half volts. I have several sets of thick wires and big alligator clips, which are connected to V+ and grounded in several places on the board. You disconnect the power, take a deep breath, and press the button. In most cases, a short-circuited device will shut itself down and emit smoke. I used this setting to fix a lot of short circuits. Although I have never used it as a paperweight, I still own one of the SCRs.

A great way to release magic blue smoke.

Another technology that may have the potential to replace batteries is fuel cells. Although trying to fill up a cell phone-sized gas tank can be troublesome.

Maybe it's not that messy. Before you were born, people had successfully filled Zippos. Modern butane is also very clean and easy to fill. There is no particular reason to mess with methanol fuel.

Butane will leak like a mofo because the nozzle is usually out of place and the adapter is garbage. When filling various butane power tools, my hands are often covered with cold boiling liquid gas.

Perhaps the filling valve on the mobile phone can be more precise than the filling valve on a 20-carat lighter.

Methanol is toxic, so it may be a bit messy

The antidote for methanol poisoning is ethanol. Easy-peasy: Stay drunk.

No more difficult than filling up the lighter.

I am not an expert, but as far as I know, fuel cells release water vapor as a by-product, and water vapor generates a lot of waste heat. I would take the liberty to say that a mobile phone that runs on 672 Rankine and is full of steam will not be the most popular or useful device.

However, fuel cells are also useful for many other larger-scale applications.

But on the bright side, your clothes have no wrinkles. In any case, the power consumption may be so low that the steam produced is also low.

A few years ago, flameless pocket heaters that looked like Zippo and used lighter liquid were very popular. Just market your mobile phone as a dual-use hand warmer.

Assuming you are a human being, *you* will release water vapor as a by-product at a rate of about 1 gram per minute. However, even though you just sit there and waste about 100 watts of heat and provide about 20 watts of power to your CPU (that is, your brain), it will not be emitted in the form of steam—just like dissolved in the air. Steam, 37C at moderate temperature.

You are right, this is a good point. However, from the information I found on the Internet, most (not all, but most) commercial fuel cells operate at temperatures of 33 Newtons or higher.

>33 degrees Newton>672 Rankine

You really like your obscure temperature scale, don't you?

@Thiru I had to googling: no, he didn't. Newton invented a temperature scale in which the freezing point of water is 0 and the boiling point is...33. I cannot explain why he chose the values ​​he made for various reference points. They are all strange numbers.

Unless you are in a 100% humidity environment.

Most of the evaporation is through your breath. If you try to breathe with a scarf around your face, the fabric will become visibly wet.

https://farm3.staticflickr.com/2190/2205713577_43ebd22e8a.jpg

Some companies have already developed it. Of course, this is a sealed proprietary ink cartridge. It is said that the airline was safe before being hacked into the "bomb", but it can only be obtained from us (when and where).

This cartridge contains a hydrogen-producing salt-"just add water", I think it is called sodium metasilicide. However, the price (USD/watt) and volume/watt are higher than ordinary AA batteries, and the fuel cell itself has not been taken into consideration.

However, "charge your phone in 1 minute" has a small problem.

Assuming you have a mobile phone, you can use a normal 5V/2A charger to charge it in one hour. The charger is very small, the cable is very thin, and the connector is a micro USB.

If you want to complete the same charge within 1 minute, you need a 5V/120A charger. This is a very powerful PSU and a thick cable, not to mention the power connector on the phone.

Easy to fix. The phone body is made of metal (like an iPhone), and the top and bottom surfaces of the phone are charging contacts. For the charger, make it a fixed base that clamps the entire phone like a George Foreman grill.

I bet it doesn’t even need to be the entire surface, you can slide it into the base with a spring clip, and you can still use the phone while charging.

Yes, but maybe not bad: USB 3.1 can provide 100W of power, so it can provide 25 kJ (7 Wh) in less than 5 minutes. If you really need a faster speed than this, you can consider using a mobile phone with a replaceable battery...

This is a valid point of view, but there are other factors that also play a role.

Supercapacitors can withstand part of the cycle without causing damage, including complete discharge, while batteries require complex management of the cycle to obtain a good lifespan.

The charging efficiency is not 100%. If designed properly, supercapacitors are better than batteries. The 10Wh of the battery may be equivalent to the 8Wh of the supercapacitor (there are many open variables here, I have this number out of nothing, knowing that the last system I used will provide about 70% of the energy input to the Lion battery, 30% of the heat and the controller). At 120A, the contacts may be surface contacts on the outside of the device, rather than the connector itself. Each picture is 25mm^2. On the other hand, the internal wires also need to be large (may be a cross section of 10mm^2), which may be a problem. The power electronics may be located in the charging station. Using smaller wires and connectors, charging for 10 minutes is quite reasonable.

It is possible that due to the voltage drop due to usage and current issues, supercapacitor-based power supplies can store and charge up to 20V, charging at 30A for 1 minute is more reasonable, charging at 3A for 10 minutes is trivial, connectors and wires-wise. This will require an internal switching power supply for the hone itself, but it will be required for almost any supercapacitor design.

Do I want my phone to charge for 1 minute? No, not in the near future, if any, for these reasons. Do I want supercapacitors in my phone instead of chemical batteries? At some point, it may take 5 to 20 years, but I will not bet the farm on it.

Single lithium battery does not require special management, only overcharge/overdischarge protection is required. And there is no problem with partial circulation at all. Conversely, since battery aging is highest at extreme state of charge (deep discharge or more than 4.1V), they like partial cycles between, for example, 20% and 80% state of charge.

You can change the battery and "charge" your phone immediately. Super capacitors can also do this.

@John Doe Maybe *you* can. The most popular mobile phones today have non-replaceable batteries.

I like the effect it has on the shape and back design of the phone, but it is not very convenient for men.

Don't forget that you can use Ohm's law a little bit to get wattage in other ways-120V at 5A can be done with a reasonable connector. Or fly under safety radar-hair below 50V @ 12A is not terrible...

In the United States, it is 100VA, and loads greater than 8 amperes must be turned off within 5 seconds. That is for power-limited circuits.

If you want to charge a 10Wh device within 1 minute, you cannot do it on a circuit with limited power. But even in the United States, the power of your power supply circuit is higher than 100W :-) So this is not a natural, physical or technical limitation, but some kind of man-made law, not a natural law. So, if you want, you can safely ignore it :-) Just don’t let yourself get caught while fast charging your phone :-)

Replace the batteries of cheap solar flashlights with super capacitors: http://www.absolutelyautomation.com/articles/2016/02/19/reusing-solar-rechargeable-keychain-flashlight

http://www.absolutelyautomation.com/sites/default/files/styles/article_image_full_node/public/field/image/160219_SOLAR_KEYCHAIN_FLASHLIGHT_SUPER_CAPACITOR_1280x720.JPG

Remember, charge = 1/2 C*V*V, where C = Farads and V = voltage. Therefore, the charge decreases in a square law manner. 1/2 voltage = 1/4 charge

Charge Q, measured in coulombs = C * V

Capacitance refers to the amount of charge stored per volt. It is a ratio.

In other words, C = Q/V

"However, the difference in capacitance and ESR (Equivalent Series Resistance) between individual supercapacitors is very small, which will lead to uneven voltage distribution. Overvoltage of supercapacitors will quickly lead to failure, so a balanced circuit is required to ensure that each supercapacitor The voltage on the capacitor is about the same.” And the lithium battery pack should have a balance circuit for battery overvoltage/undervoltage. Matching batteries in the battery pack provide more usable power.

Supercapacitors in excess of 2,600 farads are installed in German trams powered by overhead lines. The hat gives them the ability to run "off-line", just like running into a closed block. Every regular station has a set of bars on the top for charging when passengers get on and off the car, using a very fast charging function. Of course, lithium batteries will run out of charge cycles within a few weeks, but supercapacitors are rated at 500,000 to 1,000,000. Yes, the charging situation needs to be balanced, but even more so when discharging, because the weakest capacitor can be driven to reverse polarity. Their rated discharge current is 600 amps, but I have drawn more than 2 kiloamps of current without any problems. 7 dollars each. They made great adult toys. I would say that a low V hi A railgun might be possible, otherwise. ... .?

6 of my 7 will replace the malfunctioning lead-acid gel battery in the starter box of my car. The 2P3S arrangement will quickly charge from any functional car and switch to 6S (15V, dead car). Since the charging voltage of the LA battery is 14.4-14.6 volts, the car can easily withstand 15V.

There is another technology that is a bit like a hat, but does not require the manufacture of any nasty chemicals, and has an unlimited charge and discharge cycle. Compressed air. Some implementations show that it is feasible. The use of well-structured containers can control the ventilation in the event of an accident (a well-placed circumference) and make it non-hazardous.

But it seems that we are still content to save the world by digging up more rubbish from the ground and polluting third world countries at the same time.

We are a failed cause. It's just an open space. When global warming causes large-scale crop failures and starvation, I won't be by my side. It will happen...!

Unfortunately, the ideal gas law has something to say about the efficiency of this storage, and the heat loss is so great that it is really not a viable way to save energy.

"Their voltage decreases approximately linearly." This is wrong and very wrong. Even if I am not a math-oriented person, the damn discharge curve is usually exponential, far less linear.

For example: if the discharge time of a 10 volt capacitor is 500 milliseconds, it will be 3.7 volts after 100 milliseconds (the voltage drops by 63% in 20% of the discharge time)

Google the capacitor discharge graph and tell me it is linear. No, no.

You are considering an RC circuit where the load resistance is constant, but the current consumption decreases as the voltage drops.

The figure refers to constant current discharge.

In practical applications, we often have constant power circuits, so the real performance is different again!

For RC circuits, this is true.

However, for constant current loads, it is a linear drop:

iC = constant current flowing into or out of the capacitor. C = Capacitance in farads. dV = voltage change dT = time change.

Therefore, for a constant current consumption of 1 ampere, in a 1 farad capacitor, the voltage will drop by 1 volt per second.

The charge is not = 1/2 C *V^2, but the Ec or energy stored in the capacitor.

The energy stored in the capacitor, measured in joules (watt seconds) = 1/2 * C * V^2.

Therefore, if you know that you need to store a certain amount of energy (Joule or Watt*sec) and know the available capacitance or voltage, you can be sure that the latter needs to have enough energy to perform the work you want.

Not all the energy stored in the capacitor can be used because your circuit load may not work at a very low voltage, so you need to calculate the minimum operating voltage of the circuit and subtract the energy you cannot use from the total use.

Perhaps with ultra-thin dielectrics, some ultra-nano materials, we will see higher-density supercapacitors.

I would love to see this in wearable devices. Battery life is always an issue for small devices. Maybe there is a fast charging device for the smart watch as a backup for the battery.

I can see the combination of low-level beta radioactive emission and the barrier in the double-cap atomic battery! Charge slowly over the years and register for disposal. Its size must be suitable for the anticipated mass use.

In many designs by me and many people, supercapacitors have replaced the batteries, but they will never replace the batteries correctly

For everything about supercapacitors, look up robert murray smith on youtube, this guy is incredible!

At the same time, on the other end...

EFL700A39 is a very interesting battery...

10 USD for 0,7mAh? Your opinion on interesting things is different from mine. I call it curiosity. :-)

That battery can be installed in a credit card.

This is the first generation of the technology, don’t you find it interesting?

It is as thin as paper-yes. So it may have some niche uses. Stack them? - No. too expensive. :-) Okay, it's interesting from some perspectives, but it's expensive for most applications.

Are super capacitors better than Flux capacitors that can store 1.21GW of power?

In view of the current problems, supercapacitors may be most suitable for home/solar installations. There, their weight and size are irrelevant, and their longer service life will be a big advantage. Heavy gears that handle voltage fluctuations can be incorporated into existing gears to convert stored power into useful power.

Chemical batteries are still much better in terms of density.

I live in the northeast. I have always imagined storing solar energy as heat and then using the stored heat to heat my house (hot water substrate heating).

This seems to be a logical way to approach it.

My electricity bill and usage rate are not high.

Even better, heat storage itself is very useful, such as washing, bathing, and even cooking/baking.

For laundry, you need a special washing machine with a separate hot water inlet. For 90°/95° washing, it still needs a built-in electric heater. Cooking/baking with hot water as an energy source is also difficult.

@ Annie – No, you can get some models with internally heated water, so there is only one water inlet. This is clearly the norm in most parts of Europe, at least in the UK. The same goes for dishwashers.

"Please remember your old Nokia phones with nickel-cadmium batteries and how you used them for a few days before needing to be recharged. Today, we have lithium-ion batteries, and we have to charge the phones every day."

This is a bit unfair-our mobile phones today are an order of magnitude more powerful than the desktop computers I had when I owned Nokia.

Manufacturers have given up practicality in the process of seeking more (sometimes useful, sometimes not) features to wow consumers. My dilapidated old phone can last for a week, and the worn-out Li battery is only half the size of a new phone that can last a day!

In fact, any energy density graph comparing NiCd and LiIon shows that LiIon is *significantly* better.

It is not the fault of the nickel-cadmium battery, but the fault of the consumer!

I think you are all getting old, assuming you really remember the phone powered by Nicad. The Nokia 100 of my Nicad era is on standby almost all day, and one hour of talk time is considered good. A desktop charger with a spare battery is essential. We didn't get a week of standby time until the first low voltage and then the lithium battery. In the early 2000s.

so true. I just want to remember that my first mobile phone (Ericsson 337, long before it became "Sony Ericsson") had a nickel-cadmium or nickel-metal hydride battery, and I had to charge it as often as today’s Galaxy S5, every 2-3 sky. But it only has a small green/black LCD display, and the mobile Internet has not yet been invented. It was 1997, and the Internet was through a 33.6kbit/s fixed telephone modem. Later, Nokia phones equipped with lithium-ion batteries enabled a week of standby time and several hours of talk time.

I have been lurking on this site for many years and have never commented before, but since this is almost a tradition, I will continue to publish this mandatory and boring post, which plagues every interesting thing on this site Post.

Do supercapacitor phones need the same battery life as Lipo phones? Charging is just a pain because it is slow. If it charges within 10 seconds, charging more frequently will not be so painful. People used to complain about having to charge daily, not weekly...

Question: "Will supercapacitors replace batteries?"

The super capacitor was invented in the 1950s. NEC and Panasonic sold supercapacitors as consumer products in the 1970s. For all of you millennials, the date is 2017.

https://www.wired.com/2011/06/tiny-rotary-engines-could-power-gadgets-with-gasoline/ showed an idea not long ago-to make a miniature generator suitable for wearable devices.

You have a device with an amazing coulomb, an amazing discharge rate, and a wavefront that travels at close to the speed of light.

Some CO2 lasers, such as those I have fiddled with, require the wavefront velocity of light to be included in the formula. Have you calculated how thick your rubber gloves need to be? The capacitor is a 12" x 12" epoxy glass double-sided copper clad laminate.

Hacking still includes calculations... if you want to survive.

And I advocate hackers! But do math when it reaches high energy.

if you have…. Then please continue! Then use your report to impress us.

I will find the obituary by myself.

One of the super capacitor manufacturers http://www.nordmate.com

Can't wait to wait until they put a cloak on them, put a big SC on their chest, and put them on their phones, tablets, laptops, cars, trucks (go to Rivian...Normal, Il.).

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