Here at Connected Sensors, both our Water Monkey Smart Water Flow Meter and our ODEUS Smart Pipe Leak Detector are battery operated devices. And while in general battery powered devices are considered safe, we recently received the following question from a client and thought it would be worth sharing our perspective.
Client: My understanding is that battery powered IoT devices have traditionally avoided using lithium because of the potential fire risk if damaged or improperly packaged.
Can battery powered IoT devices cause a fire?
This is an important and worthwhile question to ask. After all, one of the benefits of working with Connected Sensors is the lowered risk of water damage. And while that’s all well and good, it’s not terribly helpful if the device that’s designed to protect your building from one type of damage ends up causing another type of damage. Let’s start by taking a look at batteries.
How Does A Battery Work?
We use them every day in all sorts of devices, from your laptop to your TV remote control to your car, but how do batteries actually work? Batteries work by storing chemical energy inside them and converting it into electrical energy. The electrons inside the battery flow from one material to another, which creates an electric current you can use to power a device. The three primary types of batteries available at a consumer level are alkaline batteries, nickel metal hydride batteries, and lithium ion batteries. However, there are other types available as well – Connected Sensors devices operate using lithium thionyl chloride batteries, for example. Because of the way they’re built, there are really only three different situations that might trigger a battery related fire.
Let’s take a closer look at each of them.
1. A Short Circuit
The most common way batteries start fires is through short circuits. This is true of both alkaline and lithium batteries. Electrical current by nature flows through the path of least resistance. That’s why lightning often strikes the CN Tower, for example – there’s less resistance through that than through the air or through other, shorter buildings nearby. When there’s an unintended path for electricity to flow through, it can trigger a short circuit.
There are generally only two situations where this commonly happens:
- When batteries are installed the wrong way
- When a device is tampered with or otherwise damaged
By the way Connected Sensors devices are designed, they avoid this possibility by nature.We use thermal fuses and reverse voltage protection circuitry, making it very difficult for a short circuit to occur.
A piercing is when a battery becomes physically damaged. This might be an actual hole pierced through it, like the name suggests, but it can also happen when a battery is crushed, twisted, or otherwise badly damaged. Any battery can be subject to piercing damage, but fortunately these events are extremely unlikely to occur in an environment like a commercial high rise building’s boiler room.
Everything can be overloaded. Put too much weight in an elevator, and it won’t lift. Put too much weight on a powerlifter’s dumbbell, and they won’t get it off the ground. Put too much load on a battery, and it will overload. When a device draws too much current from a battery, it breaches the battery’s maximum continuous pulse. This causes an overload, which can cause a fire.
However, because of the way Connected Sensors devices are designed, they draw very little power compared to what the batteries are able to give. In fact, they don’t even draw one tenth of what the batteries we use are capable of. So there’s virtually no risk of a battery overload.
Primary Cells Vs Rechargeable Cells
Primary cells are batteries that cannot be recharged and can only discharge once, which is the case with both alkaline and Li-SOCl (lithium thionyl chloride) batteries. These rarely cause fires. Rechargeable battery cells, on the other hand, tend to be more volatile. These batteries are based on lithium ion or lithium polymer, and they account for about ninety percent of lithium battery related fires.
These are probably the lithium batteries that cause fires you’ve heard about. This is because they’re often overcharged or are not properly monitored by the design circuitry. Because our devices use lithium thionyl chloride batteries – not lithium ion or lithium polymer – they aren’t any greater risk than regular alkaline batteries.
Contact Connected Sensors Today
Are you the operator of a high rise commercial building? If so, Connected Sensors can help you find opportunities to save money on your monthly water bill. Just about every high rise building has many water leaks, and finding them can reduce your water bill, save your building from potential water issues, and reduce your carbon footprint, all at the same time.
Don’t let your money wash down the drain.