A Battery at last!
edited March 2017 in Coatings, transdermals, other implants
Good news everyone!
Panasonic released a new battery for micro-applications (wristbands, sunglasses, pens etc).
here are the quick facts:
discharge up to 15mA, charge up to 11mA
max allowed charge temp 45°C
weights about 0.6g
Given the specs I'd call for organizing a group buy as those things are industrial parts and probably not for sale to individuals. Anyone who has connections to source them please get involved. Alternative would be to source consumer electronics that ship with such battery and aren't overpriced.
The new battery looks great, definitely more compact than my current battery, though it won't last as long for that application. I did put that project on hold a while back, several months, in favor of micro sizing the technology for use in an implant. This battery looks like a good start. Charging is still a never ending issue though.
I'll do definitely contribute to a group purchase, and I'm curious, how'd you hear about them?
4.35V. If I recall correctly Qi charging has an output of 5V?
Just looked it up, on adafruit it says:
Both would be too high for the battery without additional electronics, so keep in mind that you are going to need a bit more space than expected.
- Output Voltage: 4.8V - 5.2V
- Current: 500mA
Qi Charging Pads constantly transmit a minuscule amount of power, similar to an RFID reader.
When you place a Qi Charging receiver device, such as a phone, on a charging pad, the receiver picks up the small power from the pad.
The charger "notices" the receiver because the receiver adjusts power output from the receiving coil to the charging circuit, which results in the receiving coil getting "loaded" with power, which results in a lower current draw from the induction field. This adjustable power draw is modulated to achieve unidirectional data transmission from the receiver to the transmitting pad.
The primary purpose of the communication is to request the charging pad transmit a specific amount of power, by this method the receiver circuit in the device controls "trickle charging" and prevents the transmitting pad from outputting too much power, which also means that when no device is on the pad, it uses significantly less power than when a device is actually being charged.
I tried to explain that in a way that summed up everything involved without getting so technical that someone might have to look up things I said to understand the whole thing. There much more technical explanations out there for anyone who actually wants to build one of these themselves.
To solve any concerns, hypothetically you could adjust power transmission to prevent any possible overloading. That said, I suspect that the relatively small 0.5 volts could be decreased with some sort of small resistor in between an unmodified receiver and the battery.
As long as the charging mechanism was fairly cheap, easy to build, maybe could be made by modifying a normal Qi charger, I would find it perfectly acceptable at this point in time to not be able to use a standard, unmodified charger. If the implanted device needs a custom charger, I think it'd be plenty worth it.
I was talking to the NorthStar guys a while back, and they are using this chip. http://www.ti.com/tool/tida-00318
It's got a receiver and li-ion charger all in one and its only 5mmx5mm. Might be a good option for what ever application these batteries will be involves in
Were there ever any updates on this @ThomasEgi? Do you think a group buy is still possible?
@ChrisBot no news so far. Guess you'd have to find an industrial entity (existing panasonic customer) to do a querry. My best bet is still on NiMH coin cells simply because they are available
if you find some that are rechargeable that'd be great. I'm not aware of any of those.