I have also though of the battery. Li-ion batteries are the far most common battery used in cell phones today, and as far as i know ethylene carbonate is used as a solvent in all batteries. Diethyl carbonate is found in some, not all (I found a company that sells electrolytes for li-oin batteries, and all their products was ethylene carbonate mixed with other solvents such as diethyl carbonate) Ethylene carbonate is liquid at all relevant temperatures (this makes it easy to work with), it is supposed to have a sweet smell that even humans can pick up, it is not toxic (only in high conscentrations) and I believe it is fairly easy to get hold of.
If I were to present my dog with an brand new out-of-the-box battery, I could still not be sure of what odor the dog focuses on. Even a brand new battery has got plenty of different odors: The plastic/aluminum housing, metals, katode, anode, lithium salt, organic solvents, and even the little sticker on the outside! It would probably also be contaminated with all kinds of smells from people or machines that has handeled it before it was put in the box. To be absolutely shure of what odor I am training my dog to find, I must eliminate all possibilities for the dog to make the wrong choice - that means getting hold of pure ethylene carbonate, and use this in training.
A good example of failed K9 training is the mine detection dogs that were trained using almost intact mines. The dogs found all the mines during training, but when put into service, they would not locate real mines. The handlers had used tape on the training mines, and the dogs had in reality learned to find this tape odor. Real mines dont have tape, and were therefore not interesting.
Had the trainers extracted the explosive material, the dogs would not have had any problems locating mines - no matter the construction.
How about the antenna or circuit board - is there any unike materials used here?