The arrival of affordable Lithium capacitors on the market is so new that there are hardly simple user circuits or boards to be found. The above LIC solar charge circuit does everything that is needed for a safe use of this new electronic component.
Everything starts with a solar panel of 5 to 9 volts and 60 to 120mA. Because a voltage regulator of 3.8V is not for sale, we make an adjustable power supply from the economical HT7533. The schottky diode blocks the return current from the LIC to the voltage regulator. The Li-ion battery protection board cuts-off the load from the capacitor by reaching the 2.5V threshhold.
Test the circuit first; use a 2200uF 16V electrolytic capacitor with a LED and a 12Kohm resistor in series as load. This ‘small’ capacitor can be charged and discharged very quick. The 3.8V maximum voltage and the switch-off at 2.5V can be tested safely before using the LIC capacitor.
A lithium-ion capacitor (LIC or LiC) is a hybrid type of capacitor classified as a type of supercapacitor. It is called a hybrid because the anode is the same as those used in lithium-ion batteries and the cathode is the same as those used in supercapacitors. Activated carbon is typically used as the cathode. The anode of the LIC consists of carbon material which is often pre-doped with lithium ions. This pre-doping process lowers the potential of the anode and allows a relatively high output voltage compared to other supercapacitors.
Properties
Typical properties of an LIC are
- high capacitance compared to a capacitor, because of the large anode, though low capacity compared to a Li-ion cell
- high energy density compared to a capacitor (14 W⋅h/kg), though low energy density compared to a Li-ion cell
- high power density
- high reliability
- operating temperatures ranging from −20 °C to 70 °C
- low self-discharge (<5% voltage drop at 25 °C over three months)
- smaller package size for the same capacity compared to double layer supercaps.
My conclusion is that this solar power supply with LIC capacitor is perfectly suitable for low energy purposes. The LIC increases the storage capacity in energy harvesters and is small compared to other storage devices. The circuit specific the DW01 protection IC is designed to protect also LIC supercapacitors from the following: Over-charge, Over-discharge, Overcurrent, and Short circuit.
[…] 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. […]
[…] 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. […]