Lithium Battery Protection Board

Lithium batteries are designed to be extremely power-dense, which means they have the upper hand of a high energy density. This property allows them to be an excellent alternative for reducing the size and weight of particular projects. However, as much as they may be an advantage, they are vulnerable if not handled with proper care and may cause severe damage. To know the specifications of each lithium cell, one must take a look at the datasheet provided in the package. This allows them to understand what are the most convenient voltages, current, and temperatures that the cell can comfortably accommodate.

A lithium battery protection board can also be referred to as a protection circuit board (PCB) and is the central part of the battery. It is responsible for protecting the battery pack form incidences such as overcharging, over-drain, and over-discharging as well. Lithium-ion cells are, by far, more dangerous than any other type of batteries ever created. This is because they use an organic electrolyte capable of reacting with active materials under high-temperature conditions. The battery protection board is, therefore, the prevention measure for any explosion, fire, or damage that may occur to the cell.

What is lithium battery protection?

Lithium battery protection is the measures put in place to be able to prevent any irregularities that may occur on the cell. The main reason for battery protection is to avail the required monitoring and control, thus defending the cells against an irregular milieu or functionality. They are also put in place to protect the user from the dangers of battery failures.

Lithium cells can be highly dangerous if they are designed poorly or, in many alternative cases, abused by the user. It is, therefore, necessary for battery manufacturers to be conscious of such dangers and install the safety measure to the cells. As much as the manufacturers do their best to make the batteries foolproof, once the cells leave the factories, their fates lie in the hands of their users. It is, therefore, necessary to provide instructions in the battery pack to notify the users of the dangers of cell abuse.?

Such in-built safety measure may include:?

· Electrolytes-Chemical inhibitors are added to electrolytes within the cell, making them flameproof in cases of abuse by the user, which could lead to a fire.

· Robust separators- When cells overheat, this might cause the separators to melt and thus leading to short circuits. Rigid separators are therefore installed which do not distort under extreme temperatures.

· Cell chemistry- High energy and power densities require more reactive chemical brands/mixes that may be dangerous. Cell manufacturers, therefore, introduce chemical retardants to minimize the risk and compromise on the maximum power.?

· Circuit Interrupt Device (CID)- Manufacturers induce a CID which, in the event of excess pressure gas within cells, interrupts current flow.?

· Shrouded terminals- Designed to protect the user from accidental short circuits & connection of incorrect charges to the cell.?

· PTC- This refers to pressure, temperature &current, which is a safety device that prevents current surges and interferes with the circuit in case of excessive temperatures or pressure within the cell.

· Efficient cell construction- Thermal conduction paths have been installed into the high-power cells to enhance excellent thermal performance. This, in turn, helps get rid of excess heat within the cell, thus preventing localized hotspots.

What is the BMS protection board?

Firstly, a battery management system (BMS), is an electronic system that manages a cell. This is done through monitoring the state of a cell as represented by various factors such as voltage; temperature; current; state of charge; state of power; state of safety.?

How does a lithium battery BMS work?

The functions of a BMS may include:

· Protection

· It is the duty of the BMS to provide external cell protection to the battery. A BMS may protect the battery from irregular operations within it, such as:

1.High deposition temperatures?

2.Overcharging

3.Overheating

4.In-built pressure within the cell

5.Excessive current flow during charge/discharge

6.Abuse by user

7.System isolation

8.Occurrences of short circuits

· Communication

It is the work of the central control unit of a BMS to communicate with its hardware internally at the cell level or externally with a device that is of a higher level.

· Energy recovery

The BMS tends to also control the recharging of the cells by taking the recovered energy back to the battery pack.

· Optimization

BMS ensures that the cells within the lithium battery pack are kept at the same voltage. This helps maximize battery capacity and at the same time, inhibit localized undercharging & overcharging.?

· Computation

The BMS may calculate values based on:

1.Charge current limit, CCL

2.Discharge current limit, DCL

3.Total number of charge cycles

4.The full time of operation

5.The total energy that has been delivered

6.Open circuit voltage

7.The energy produced since last charge cycle

· Battery connection to load circuit

The BMS may also constitute a precharge system that allows safe connection between the cells and loads, thus reducing excessive inrush currents.?

Final thoughts

One should never use a lithium battery without the protection cells as a slight misuse could destroy the battery and risk it catching fire or exploding. As much as cell manufacturers do their best to install safety precautions into the batteries, it is the user’s job to care for it. Never disregard the instructions offered in the battery pack as most users do since these are your guide to full battery capacity maximization.

This article has covered a wide range of battery protection and how it works. All you need to do is carefully follow the guidelines provided and also get to know more about lithium batteries to care for them properly. No one will teach you the apparent consequences of cell abuse as they should run through your head every time you use a lithium battery. For its protection and yours, stick to the script and everything else will fall in place.