Can lithium-ion batteries get wet?
Well, there may be two answers to this question, Yes and No. Modern lithium-ion batteries are designed to be waterproof with the cases completely sealed together with the terminal feed-throughs. This prevents moisture from infiltrating the battery. Also, the stickers wrapped around them are plastic-like and also designed to be non-porous preventing the contact of the metal alloy casing with the water molecules. However, just when the lithium-ion batteries were new to the industry, there wasn't much effort installed into making it waterproof. Their materials of manufacture were somehow heavily flawed as compared to the current lithium-ion batteries and thus, water was capable of penetrating through.
However, one should note that the materials used to produce batteries and even lithium-ion cells makes the batteries denser than water. This means that any battery placed on the surface of the water would sink. It is advised not to submerge a battery in water because this could compromise the seal on the casing and therefore get the batteries wet. When water leaks into the cells, it could cause rapid oxidation of metal contacts within the cells and this could ultimately reduce the performance of the battery pack in general. Water is also capable of interfering with the battery management circuitry and thus causes violent reactions within the cells.
What happens if you put a lithium-ion battery in the water?
When you put lithium-ion batteries in water, it will sink as the materials used in its manufacture tend to be denser than water. Lithium-ion batteries are designed to waterproof because of their airtight sealing on to casing and thus prevents it from getting wet. However, when submerged for extended periods, the water can find a way to penetrate the cells and may cause reactions that would otherwise diminish the performance of the batteries.
However, the water may not do extreme damage as only a few components may be affected or damaged in other cases. Firstly, as explained before, the water can cause rapid oxidation of metal contacts within the cells. It can also induce chemical reactions of various chemicals in the cells as it can also be a catalyst when different chemicals come into contact with each other. Also, the water may only tend to harm small circuit trace. It can even damage the PCB, LED leads and control circuits. The batteries would, however, have a higher resistance short-circuit. This resistance would drain the cells faster but would not be high enough to reach critical or hazardous conditions.
Do lithium-ion batteries explode in the water?
Well, unless you have C4 and a timer tied to it when thrown into the bottom of the ocean, then it is improbable for the batteries to explode on their own in the water. There have never been any reported cases of batteries exploding in water ever since their invention unless it's a diver's crazy idea to use bombs in the form of a battery to chase away sharks at a beach. Lithium-ion batteries may contain highly reactive contents within their cells but these materials may not be capable of sustaining or inducing an explosion in the water.
When water leaks into the cells, as mentioned earlier, which is also a rare occurrence considering that the new battery designs are waterproof, only a few components will be affected. Yes, the water may induce chemical reactions of highly-volatile materials but the internal resistance created would be too low to cause an explosion. Also, short-circuits may occur, but common sense tells us that a battery wholly submerged in water cannot ignite a flame. Well, unless it's in a cartoon or fantasy film where characters would even start fires underwater, I don't think there's anything to fear about when it comes to lithium-ion battery explosions in water.
Can you take any measures?
Of course, there are various measures you can take to make your batteries waterproof in case you doubt their capabilities in that sector or the batteries have been slightly damaged, physically, and portray a weak point from which water can take advantage of. There are a few steps in which you can take by yourself to make your cells waterproof. However, take caution when handling batteries of any kind and especially lithium-ion batteries.
If you handle a lot of outdoor tasks or your activities take place in foul weather, keeping your batteries dry can be quite a hard thing to do especially if you enjoy underwater explorations and need a flashlight. Water not only makes battery rust faster, but it also creates a conductive path around the battery top, which quickly discharges it and thus leading to a shorter lifespan and leaving you all alone in the dark corners of a blackout because your flashlight went out. Waterproofing your batteries is very easy and doesn't require you to purchase anything you may not already have that is costly. The following are steps for carrying out the waterproofing project:
Step 1. Materials needed
Technically, all you would need for this experiment is a waterproofing coating material. You don't need a special coating purchased from the store as there are many materials around your home that can do the trick just fine. These materials can include urethane waterproof coatings and rubberized paintings. Well, if you don't have these at your place, it's very much understandable as they aren't a common sitting at home. You can however, run to the store and purchase a silicone or urethane conformal coatings. The reasons why we prefer these materials is because they soak well, stick firmly to meatal and dry well. Also, alternatives such as standard oil-based paints or nail polish will do just fine but are however, hard materials that may chip off upon drying.
Step 2. Get to work
You only need to dab your coating material around the battery terminals, of which you are advised to use a material that starts out as a liquid so that it can soak thoroughly into the small corners of the terminals. During application however, on the positive terminal, where a dimple is visible, do not coat that feature.
Step 3. Wait for it to dry and go play
Once the liquid coating is dry, you can now go out and play in the rain or explore the deep waters at night.
Lithium-ion batteries can be termed as battery swimmers as they can handle wet conditions due to their sleek and airtight designs that prevent infiltration of water. However, you are still advised not to expose the batteries to water, as this can degrade their performance.