Definition of 18650 max current and influencing factors

So in this article, we’ll be delving into the 18650 max current, how it is achieved, how to properly maximize it, and the best way to properly use it.

What is battery current

Batteries can store chemical energy which can then be converted to electrical energy in the form of electrons that flow from one electrode within the battery to another. This flow of electrons is what generates electricity in the form of electric current. The number of active electrons that flows from the battery to a device in a circuit at any given point in time is what is known as battery current.

How is high current in lithium 18650 battery generated

The positive electrode material of the lithium 18650 battery is usually composed of lithium active compounds, and the negative electrode is carbon with a special molecular structure. The main component of the common cathode material is LiCoO2. When charging, the potential applied to the two poles of the battery forces the compound of the cathode to release lithium ions, which are embedded in the carbon whose molecules of the anode are arranged in a lamellar structure.

During discharge, lithium ions are precipitated from the carbon in the lamellar structure and recombine with the compound of the positive electrode. The rapid movement of lithium ions creates a 18650 max current.

Definition of 18650 max current

A max current such as a 18650 max current is defined as the highest level of ions continuously flowing from a battery through a conductor in a circuit at any given point in time. The maximum current refers to a limit value of the current that can be endured without affecting the safety of the equipment. Generally, it is only allowed to appear for a short time. This maximum current must be achieved under normal usage conditions without exceeding the recommended temperature levels which may cause damage to the circuit.

What are the battery types of 18650 battery

18650 batteries come in 2 major types which are Lithium Ion Phosphate and Ternary Lithium battery types. A 18650 Lithium iron phosphate battery is an efficient battery type that is made using a Lithium iron phosphate cathode material which enables it to supply energy at steady constant voltages and also able to have a higher number of charge cycles than most lithium-ion batteries, up to 5000 cycles.

A 18650 ternary lithium battery is an equally efficient battery type as it uses 3 distinct metal oxides as anode materials which include cobalt, nickel, and manganese. This combined anode design gives the ternary battery an exceptional performance level and high energy density.

What are the influencing factors of the 18650 max current

A 18650 max current has several factors which influence how effectively this current level is achieved some of which include;

● The surface area of the electrode: The higher the surface area of the active electrode within the 18650 battery, the higher the electron/charge transfer capacity of such a battery making a 18650 max current possible. Different electrode area will cause different resistance of the electrolytic cell, thus affecting the current. The difference in electrode area mainly affects the current density on the electrode surface.

● Chemical composition of the electrodes: Since the level of current generated and transferred in a 18650 battery depends on the efficiency of the electrodes, the chemical and structural composition of the electrodes is a contributing factor to achieving a 18650 max current.

● The quality of the electrolyte: The electrolyte within a 18650 battery serves as a medium for electron/ion transfer from cathode to anode and hence the stability, quality, and quantity of the electrolyte affects the ability to achieve a 18650 max current.

● Discharge rate: The rate of discharge or C-rate describes how fast current is being pulled out as power from the battery, so using the recommended maximum C-rate will equally produce the recommended 18650 max current.

How to calculate 18650 max current

When dealing with batteries, calculating the current rating, such as the 18650 max current, is a common practice that should be carried out to determine how best to use the battery. To do this the mAh rating of the battery and the C-rate of the 18650 battery need to be used. For instance, a 18650 battery rated at 2700mAh with a C-rate of 1C can be calculated by multiplying both values. This means the max current for this 18650 battery is 2.7A per hour. Subsequently, if the C-rate is 0.5C, the max current would be 1.35A per hour.

18650 voltage at charge and discharge maximum current

The charging and discharge rate of a 18650 battery is also known as the C-rate and for most 18650 battery cells, it is usually 1C. The maximum charging voltage of a 3.7V 18650 battery cell is commonly at 4.2V at which point it is recommended to cease charging. 3.2v LiFePO4 18650 battery maximum voltage is 3.65v. Also, the 18650 battery cell should not be discharged below 3.0V, all of which can be automatically achieved with a built-in BMS designed inside the battery.

What is 18650 max current when charging and discharging

For a high-efficiency 18650 lithium iron phosphate cell, it could have a high discharge or C-rate of up to 10C and for a standard 2700mAh battery, this means the 18650 max current could be as high as 27A. This max current rate could be maintained for as long as the rated maximum voltage isn’t exceeded which is regulated by the in-built BMS.

How to increase the current of the 18650 battery

The actual 18650 max current level for most batteries cannot be exceeded as there is a rated capacity the battery is built to operate at. But the overall current can be increased by connecting multiple 18650 cells in parallel to maximize the current output. In practical applications, 5 regular 1C 18650 cells can be connected in parallel to enable them to handle a much higher current load. Therefore, there are many lithium 18650 battery packs on the market, which are used as power wheels battery, etc.

Can the 18650 battery be customized with a desired current rating

Most quality odm lithium ion battery pack manufacturer can in fact customize a 18650 battery to a desired current rating. Since the 18650 cell has a maximum capacity range from 1500mAh to 3500mAh, it can be customized to fit within this range as ordered by the customer. This will enable a desired 18650 max current level needed by the customer for any desired application.

What happens if the 18650 current is too large

Each 18650 battery cell has a rated max current and voltage level which should not be exceeded as it would lead to an increase in temperature which may damage the battery and reduce its overall capacity. This is where a BMS is needed. A high-quality 18650 battery would come equipped with an in-built BMS which would regulate current draw such that the 18650 max current and voltage are not exceeded to ensure safe use.