Battery Short Circuit

Batteries, especially lithium-ion, are widely used in the world today. You will find them in many electrical devices like smartphones, tablets, laptops, and video game consoles.

Even though these batteries are very convenient as they can be recharged, they can cause a lot of issues if not protected well. We have seen batteries explode in many situations, causing serious damage and even harm to people.

Short-circuiting is one of the biggest threats to battery safety and performance. It can cause the battery to lose its capacity rapidly, swell and become permanently damaged.

Therefore, there is a need to have a protection system in place that ensures such issues never occur. Luckily, modern batteries have built-in systems that perform these tasks. They are called short-circuit protection systems.

In this guide, we will discuss what these systems do and why they are important. Keep reading to learn more.

Battery Short Circuit Protection

Batteries have become extremely important in the modern world. But they store and produce electrical energy, which means they are prone to issues like short-circuiting.

The short circuit protection system is designed to cut energy transfer by disconnecting the circuit whenever there is danger. This system is like a switch that turns off when it senses certain conditions.

What is battery short circuit?

To understand how circuit protection works, we need to start by understanding the term short circuit. What does it mean?

In simple terms, a short circuit means to have a load that is far beyond the normal battery range. Batteries, whether high or low voltage, will short circuit under low or zero resistance loads.

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Such conditions can lead to damaging consequences for the battery. And if maintained for an extended period, the load may also face the same damages.

At best, the battery will drain too fast, most times within seconds. And at worst, your battery will catch fire and explode, affecting even the load.

Short Circuit Protection

As you can see, the damages from short-circuited batteries can be devastating. The last thing you want is to buy a new battery or device because of such issues.

And that is why you need a reliable protection system in place. Battery short circuit protection cuts any connection that could conduct electrical energy when it senses too much current through the circuit.

The wiring of any high-current battery, like a car battery, comes with a fuse, which opens whenever there is a short circuit. On the other hand, low-current batteries don’t really need such protection where the short-circuit current is too low for any.

With that in mind, it is clear that short-circuiting is a serious issue in high-current batteries and that proper protection is necessary. Manufacturers are well aware of the risks that come with these products, and they have put measures in place to give consumers assurance of safety through circuit breakers.

Summary

A short-circuit state between external electrodes causes the battery to discharge too fast and beyond normal limits. This causes the battery to generate heat. If the temperatures keep rising, the battery will overheat and potentially catch fire or explode.

Short-circuit protection is a system that cuts off a discharge current within a microsecond of detecting the issue. This function is similar to discharge overcurrent protection. However, the short-circuit protection reacts to a large discharge current.

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Battery Short Circuit Protection Example – Relays

You can make short circuit protection using a relay. This is a simple, cheap, and very effective way to ensure the battery terminals don’t come in contact to cause the short circuit.

We understand smart batteries come with BMSs, which monitor and protect the batteries internally. But what if you are using a battery that does not have such features? Lead acid batteries are an example of batteries that can easily short-circuit if you are not careful enough.

To create the protection circuit, you will need a 5V or 1V relay module, depending on your battery. You will also need green and one red LED, two resistors, and one push button for opening the current.

Connect the negative terminal of the battery to the common terminal on the relay and then the positive terminal to one end of the relay coil. Next, connect the push button between the negative and the second terminal of the coil on your setup. Now, set the red LED between the normally closed terminal and the negative terminal, and the green LED?between the normally open and the battery’s positive.

This system will close and open appropriately to protect your battery and load from any potential damages. It works on the principals that current always attempts to flow from the path of least resistance. It will keep your battery and load safe, also saving you from spending a lot of money on repairs or buying a new battery.

Battery Short Circuit Test

Tests can be done to evaluate the electrical performance or safety of batteries. This is a common practice for lithium-ion batteries. The tests include continuous charging tests, internal short circuit tests, overcharging and over-discharging tests, and large current tests.

Short circuit tests are done to simulate wrong battery user conditions. The test can include short-circuiting a batter from the outside to show conditions that can cause fire or rapture.

The test is quite simple. It can be done by connecting the positive to the negative terminals of a battery through a circuit load of 80+/- 20 ohms. The temperature of the battery should be recorded too.

Battery Short Circuit Current

Short circuit currents differ from battery to battery. Some batteries may have a lower current while others may be more significant.

In industrial standby batteries, the current may be high when where normal characteristics say otherwise. It is not uncommon to have even smaller batteries with several thousands of amperes of currents. In larger batteries, such current may exceed 40,000 amperes.

At low charge, the short-circuit current may be the same as the published figure. This is because the internal resistance remains relatively the same except for when the battery is fully charged.

You can always carry out a test to determine the short-circuit current. This will help you determine how much load the battery can support and how to keep it safe.