CR2032 Protection Circuit Designs And Safety Requirements

Inverse Current
   CR2032 lithium batteries are not rechargeable, and when used with another power source please use precaution that current does not flow from the other source into the cell. For safety’s sake, and to receive UL approval, the circuit has to include either two blocking diodes in series or one blocking diode and one resister in series. Use a silicium diode and limit any re-charge leakage by the diode to 1% of the battery's rated capacity over the product's life. Any higher re-charge rate may allow harm to come to the battery and shorten battery life.   

Short Circuits
   When short circuited, CR2032 batteries need time to recover before measuring the cell's voltage. After soldering, a CR2032 battery may test as defective - but rest assured, it’s not. Any shorting decreases the performance of these cells' capacity and therefore should be avoided or reduced to the absolute minimum.

   Use extreme care when wave soldering CR2032 batteries with terminals. Some manufacturers have resorted to placing explosion shields over the solder bath because of these cells' reaction to extreme heat.

   There are other means of protecting the battery and keeping it within a safe operating margin, but these are the most common protection circuit designs. Some batteries have a pressure sensor that cuts off the circuit once the cell reaches a certain internal pressure, and other batteries relay diagnostic information to a nearby computer system. Be reassured, though, since batteries are becoming safer and safer every year.