Source: NBC News
quote: Wh isn't misleading. It's also not W/h, but Wh. The same it's Ah and not A/h. There's no need to specify both U and I if you can put it in one more handy value, P.
quote: When you know the Ah of a battery you still don't know how fast you can recharge it, some faster, some slower, depending on the technology. Just current technology lies around 1C-5C, but that's just a current limit and not a limit of future batteries.
quote: And btw., we're talking about supercapacitors, which don't have such a limit at all. They get charged with a constant voltage and take what their internal resistance allows.
quote: They can't explode and you don't need a charge controller. You set it to a fixed voltage and give it whatever Ampere it wants.
quote: Incorrect. All modern rechargeable batteries can change at a rate of at least 1C. Whether or not they can go above that depends on their chemistry and construction. Also, at 1C, you will need a minimum of 1 hour to charge a given battery.
quote: That's not correct. Generally, batteries that are more energy dense for a given chemistry have much slower charge and discharge rates. Compare the Panasonic UR18650ZTA and the UR18650SAX.
quote: Same manufacturer and basic chemistry, but one can be discharged at 8C without affecting the final capacity much but another starts to quickly lose capacity even discharging at 1C.
quote: The extreme example of this are high capacity rechargeable lithium coin cells, where a 3032 sized cell can have a 100mAh capacity, but won't be able to charge or discharge more than 1mA.
quote: Yes, they would, if you think of the batteries as buckets the bigger the bucket the longer it takes to fill or empty it using a fixed flow of water. It's not necessarily that they charge or discharge at different rates, it's just that a larger capacity takes longer to fill and lasts longer under load.
quote: One battery is 1350 mAH and the other is 3000 mAH; the larger capacity battery does not experience as much of a voltage drop under load as the smaller battery does, but that doesn't really counter what I said.
quote: All I said is that you can charge any modern rechargeable battery at 1C, with the implication being that it is safe to do so. You will not "lose capacity" but your battery may not be suited to a high-current application.
quote: You're missing the point, the battery makers tailor the geometry of the battery to optimize for high current draw or high capacity.
quote: Look at the discharge graphs, the high capacity ZTA has almost a 250mV drop between the 0.2C (0.6A) and the 1C rate (3A), while the low capacity SAX has only about a 100mV drop between the 0.2C (0.27A) and the 2C rate (2.7A).
quote: You linked to a Lithium ion CR3032 that could be charged or discharged at 1C, I linked to one that cannot. Your blanket statement of "any modern rechargeable battery at 1C" is wrong.
quote: I'd be willing to bet money that the one you linked to could be charged at 1C even if the spec sheet says no. I would also say that what's commonly accepted by most people as a 'rechargeable battery' is not one of these niche button cells, rather it would be a cell phone, camera battery, AA or AAA type - all of which will charge and discharge safely at 1C.
quote: A button cell is hardly niche, there's billions of them made each year. They're just tailored to a different market, low self discharge and high capacity in a small size without a need for much current draw.
quote: 1C isn't some magic number, it's just that rather than choose to list energy storage in joules or some other unit, they settled on Ah. That many batteries can be charged in an hour or less doesn't grant some special physical significance to 1C.
quote: This work is an important initial step in introducing this new electrode material in supercapacitors to replace conventional batteries in flexible electronic devices.
quote: And not every modern battery can get charged with 1C. That's just wrong!A Li-Ion battery with 3.7V and 1Ah has a energy of 3.7Wh!So if you charge it with 1Ah for one hour, it's almost full.
quote: The same if you put 3.7W in it in one hour it's full, too. (for example by connecting it to a 3.7V 1Ah power source)It's nothing different, it's the same, expressed in a different unit.
quote: Are you joking with me? Why should you charge a SC above it's rated voltage? Why do you connect it to a battery at all?
quote: The idea is to replace a chemical battery with a SC in future devices, nothing else. And she never claimed anything else. Just read her paper:
quote: The kilowatt hour, or kilowatt-hour, (symbol kW·h, kW h or kWh) is a unit of energy
quote: The watt is a derived unit of power in the International System of Units (SI), The unit, defined as one joule per second, measures the rate of energy conversion or transfer.
quote: Nobody who knows what they're talking about is going to be referring to battery capacity in W/H.
quote: If you have a typical 12V battery and a 2V "super" capacitor, the battery will overload that capacitor.
quote: No, that's not the idea. Capacitors were never intended to replace batteries and never will
quote: however battery technology may advance further as new designs allow them to store more energy, perhaps even generate energy by means of a chemical reaction.
quote: It's not really her paper, is it? Not that it matters because until she has a functional prototype it's all just conjecture
quote: My last reply to your ignorant dumb posts:
quote: Watt is not a unit of energy . Watthour is a unit a energy . And I never used Watt/hour (W/h) as you constantly did, I always wrote Watthour (Wh). If you don't believe me, then take a look in your physics school book, or
quote: So again, Wh (Watthour), because Wh is a unit of energy, gives you the amount of energy stored in a battery!
quote: I never wrote W/h, I always wrote Wh and pointed you, several times, to this fundamental mistake you constanstly did.
quote: Of course, if you're an idiot you can bring everthing to explode. But it's a fact, a supercapacitor does not need a charging circuit, just a constant voltage (of course the correct voltage). That's all I said. Everything else you wrote came from your wrong imagintation.
quote: That's exactly the use case of a super capacitor: To replace a chemical battery!
quote: chemical batteries (ni-mh, li-ion) store the energy chemically, they release it with a chemical reaction!
quote: It's what SHE wrote. It's her work! You must be really jealous.
quote: She also build the prototype, shown in the picture of this article, produced in the lab with a Prof supervising her (of course wasn't she allowed nor able to produce it totally on her own)quote
quote: Amps are the units of electrical energy a battery has "available for transfer" and volts tell us the rate of said energy transfer.
quote: Being a derived unit doesn't make them any more conceptual than these base units.
quote: and for the last time, stop using W/H as watthour, it is not watt per hour, check your electricity bill if you ever get confused about the units again, seriously...
quote: Watt is not a unit of energy . Watthour is a unit a energy