The internal resistance of lithium battery is one of the important indicators to measure the performance and power output capacity of lithium battery.
Correctly measuring the internal resistance of lithium batteries can help us understand the health and energy loss of the battery, so that we can better use and maintain lithium battery products.
Let's take an in-depth look at the measurement method of lithium battery internal resistance.
We need to understand what internal resistance is.
Internal resistance is the resistance to the flow of current inside the battery, which depends on factors such as the chemical reaction of the battery, the electrolyte, and the electrode material.
The magnitude of the internal resistance directly affects the voltage stability and discharge performance of the battery.
Measuring the internal resistance is important to evaluate the performance of the battery.
There are two common methods for measuring the internal resistance of lithium batteries: the open-circuit measurement method and the load measurement method.
The open-circuit measurement method calculates the internal resistance by measuring the voltage decay rate of the battery in the no-load state.
The specific steps are as follows:1Place the lithium battery in an open-circuit state and wait for the voltage to stabilize.
2.Use a digital multimeter or a specific internal resistance tester to measure the battery's open-circuit voltage.
3.Connect the load resistor so that the battery starts discharging.
4.Measure the voltage after the battery is discharged, recording the change in voltage over a period of time (usually a few seconds to a few minutes).
5.According to the voltage change rate and the magnitude of the current, the internal resistance of the lithium battery is calculated.
The advantage of the open circuit measurement method is that the measurement is simple and fast, but since there is no load at the time of measurement, the obtained internal resistance value is not completely accurate and is for reference only.
The loading measurement method calculates the magnitude of the internal resistance by adding a load with a known current to the lithium battery and measuring the degree of voltage drop.
The specific operation is as follows:1Select a load resistor of a certain current size and connect it to the positive and negative poles of the lithium battery.
2.Use a digital multimeter or a specific internal resistance tester to measure the terminal voltage of the battery and record it.
3.Turn on the load circuit so that the lithium battery starts to discharge.
4.The terminal voltage of the battery is measured within a certain period of time (usually tens of seconds to minutes) and recorded.
5.The internal resistance of the lithium battery is calculated according to the voltage drop and the magnitude of the current.
The loading measurement method is more accurate than the open circuit measurement method because the load is added, which is closer to the real working state of the lithium battery.
In addition to the above two basic measurement methods, there are some improved measurement methods, such as the AC internal resistance test method and the electrochemical AC impedance spectroscopy test method.
These methods can provide a more comprehensive understanding of the internal resistance of the battery by testing the lithium battery with an AC signal, but the operation is complex for the average user and requires specialized equipment.
There are many ways to measure the internal resistance of lithium batteries, and users can choose the method that suits them according to their actual needs and situations.
Whether it is an open circuit measurement method or a loading measurement method, it can provide us with important information about the performance of lithium batteries, helping us to better use and care for lithium battery products.
1.The open-circuit measurement method calculates the internal resistance by measuring the decay rate of the voltage at no load.
2.The load measurement method calculates the magnitude of the internal resistance by adding a load with a known current to the battery and measuring the degree of voltage drop.
3.AC internal resistance testing and electrochemical AC impedance spectroscopy are more advanced methods that provide a more complete understanding of the internal resistance by using AC signals to test the battery.
4.Users should choose the appropriate measurement method according to their needs and actual conditions to understand the performance and health of the battery.