I'm building a device with a battery life of at least one year. The options are to use alkaline batteries or lithium ion (with appropriate capacity). I suppose the self-discharge of both batteries is small enough for this use. The lithium ion battery lifetime is usually measured in cycles, however I suppose in this case the shelf/calendar life is the limiting factor. I've tried searching some shelf life numbers for lithium ion, but it seems the value is 1-10 years depending on the source, also I haven't found any datasheets stating the shelf life (searched for some Samsung, Panasonic and LG 18650 cell datasheets as a reference).
- How/where could one estimate/find performance of the lithium ion battery in this case?
The main reason to use a lithium ion battery in this device is that it can be slim compared to for example AAA batteries. However I cannot even come up with any commercial device (for comparison) that would have such battery life with a lithium ion battery. The batteries and required charging chips are rather unexpensive in my opinion. Now that I think of it, I haven't been able to find reliable source for the self-discharge either, some sources state ~2% and some 10% and the datasheets state nothing.
Why would one not make a device with one year battery life using lithium ion batteries? Is the reason perhaps the combination of vague shelf life, vague self-discharge and slightly higher cost?
Is there any research on how much battery life a device with a non-rechargeable battery should have from the usability point of view? (slightly unrelated)