How to judge the performance of lithium batteries? Mainly looking at voltage, capacity, and internal resistance

Usually, when choosing batteries, the first thing we need to consider is the performance of these types of batteries, because only batteries with good performance in all aspects can play a better role in the use process. Lithium batteries are currently widely used in the market, covering various fields. As a result, the popularity of lithium batteries has led to many mixed products being sold on the market, Allowing consumers to frequently purchase batteries of poor quality, which can affect their effectiveness. Therefore, many people blame lithium batteries for their poor performance and even resist using them. Actually, it's not that lithium batteries are bad, but do you really choose lithium batteries? To address this issue, let's take a look at how to distinguish the performance of lithium batteries or how to choose high-quality lithium batteries!

1. Lithium battery capacity

   
   

The capacity of a battery can be divided into rated capacity and actual capacity. The rated capacity of a battery refers to the amount of electricity that the battery should provide when discharged at a rate of 5C to the termination voltage under an ambient temperature of 20 ℃± 5 ℃, expressed in 5C. The actual capacity of a battery refers to the actual amount of electricity released by the battery under certain discharge conditions, mainly influenced by the discharge rate and temperature (therefore, strictly speaking, the battery capacity should indicate the charging and discharging conditions). Capacity units: mAh, Ah (1Ah=1000mAh).

2. Lithium battery internal resistance

The internal resistance of a battery refers to the resistance experienced by the current flowing through the battery during operation. It consists of two parts: ohmic internal resistance and polarization internal resistance. A high internal resistance value of the battery can lead to a decrease in the working voltage of the battery discharge and a shortened discharge time. The size of internal resistance is mainly influenced by factors such as battery material, manufacturing process, and battery structure. The internal resistance of a battery is an important parameter to measure its performance.

3. Lithium battery voltage

Open circuit voltage refers to the potential difference between the positive and negative poles of a battery when there is no current flowing through the circuit in a non working state. In general, the open circuit voltage of a lithium battery is about 4.2V when fully charged, and about 3.0V when discharged. By detecting the open circuit voltage of the battery, the state of charge of the battery can be determined.

4. Lithium battery discharge platform time

The discharge platform time refers to the discharge time to a certain voltage when the battery is fully charged. For example, for a certain ternary battery, the discharge platform time of 3.6V is measured. When the constant voltage is charged to 4.2V and the charging current is less than 0.02C, the charging is stopped and fully charged. Then, it is left for 10 minutes. The discharge platform time at any rate of discharge current is the discharge platform time at that current. Due to the voltage requirements of some electrical appliances using lithium-ion batteries, if the operating voltage is lower than the required value, it may cause malfunction. So the discharge platform is one of the important standards for measuring the performance of batteries.

5. Lithium battery charging and discharging rate

The charge discharge rate refers to the current value required for a battery to discharge its rated capacity within a specified time. 1C is numerically equal to the battery's rated capacity, usually represented by the letter C. If the nominal rated capacity of the battery is 10Ah, then 10A is 1C (1 rate), 5A is 0.5C, 100A is 10C, and so on.

6. Self-discharge rate of lithium battery

Self-discharge rate, also known as charge holding capacity, refers to the holding capacity of the battery under certain conditions when the battery is in an open circuit state. Mainly influenced by factors such as the manufacturing process, materials, and storage conditions of the battery. It is an important parameter for measuring battery performance.

After reading these, it's easy to understand. You may also be confused: why do seemingly small lithium batteries have so many principles? In fact, any battery has its own advantages and disadvantages. The advantages of lithium batteries are high voltage, high energy density, long cycle life, friendly environmental performance, small self-discharge, rapid charging and discharging, wide operating temperature range, etc. They are also recognized as the best batteries so far. Lithium batteries are mostly used in new energy electric vehicles, some military equipment, communication base stations, etc, As a result, it has demonstrated its astonishing value.