How to set up a safe lithium battery protection -Lithium - Ion Battery Equipment

How to set up a safe lithium battery protection circuit -Lithium - Ion Battery Equipment



According to statistics, the global demand for lithium-ion batteries has reached 1.3 billion, and with the continuous expansion of the scope of use, this data is increasing year by year. Because of this, with the rapid increase in the use of lithium-ion batteries in various industries, the safety performance of batteries has become increasingly prominent, which requires not only excellent charging and discharging performance of lithium-ion batteries, but also higher safety performance. Why did the lithium-ion battery catch fire or even explode? What measures can be taken to guard against it?

The explosion of notebook battery is not only related to the processing technology of the lithium-ion battery cell used in it, but also to the battery protection board packaged in the battery, the charge and discharge management circuit of the notebook computer, and the heat dissipation design of the notebook. The unreasonable heat dissipation design and charge and discharge management of notebook computers will overheat the battery cells, greatly increasing the activity of the cells, and increasing the probability of explosion and combustion.(Lithium - Ion Battery Equipment)

Study on the Composition and Performance of Lithium Ion Battery Materials

First, let's understand the material composition of lithium ion battery. The performance of lithium ion battery depends on the structure and performance of the internal materials of the battery. The internal materials of these batteries include cathode materials, electrolytes, diaphragms and cathode materials. The choice and quality of positive and negative materials determine the performance and price of lithium ion batteries. Therefore, the research on cheap and high-performance anode and cathode materials has always been the focus of lithium ion battery industry development.

Carbon materials are generally selected as cathode materials, and the current development is relatively mature. The development of cathode materials has become a critical factor that restricts the further improvement of the performance and the further reduction of the price of lithium ion batteries. In the current commercially processed lithium-ion batteries, the cost of cathode materials accounts for about 40% of the total battery cost. The reduction of the price of cathode materials directly determines the reduction of the price of lithium-ion batteries. This is especially true for lithium-ion power lithium-ion batteries. For example, a small lithium-ion battery for a mobile phone only needs about 5g of positive material, while the lithium-ion power lithium-ion battery for driving a bus may need up to 500kg of positive material.

Although there are many kinds of cathode materials that can be used for lithium ion batteries theoretically, the critical component of the common cathode material is LiCoO2. During charging, the potential added to the battery poles forces the compounds in the cathode to release lithium ions, which are embedded in the carbon with a lamellar structure of the anode molecules. During discharge, lithium ions are separated from carbon with the lamellar structure and re bound with the compounds of the cathode. The movement of lithium ions creates an electric current. This is how lithium-ion batteries work.

Design of charge and discharge management of lithium ion battery

When a lithium ion battery is charged, the potential added to the two poles of the battery forces the compound at the positive pole to release lithium ions, which are embedded in the carbon with a lamellar structure arranged at the negative pole. During discharge, lithium ions are separated from carbon with the lamellar structure and re bound with the compounds of the cathode. The movement of lithium ions creates an electric current. Although the principle is very simple, in actual industrial processing, there are many practical problems to be considered: the cathode material needs additives to maintain the activity of multiple charge and discharge, and the cathode material needs to be designed at the molecular structure level to accommodate more lithium ions.

Although the lithium ion battery has all the advantages mentioned above, it has high requirements for the protection circuit. In the process of use, we should strictly guard against overcharge and overdischarge, and the discharge current should not be too large. Generally speaking, the discharge rate should not be greater than 0.2C. The charging process of lithium ion battery is shown in the figure. During a charging cycle, the voltage and temperature of the lithium ion battery should be tested before charging to determine whether it is rechargeable. If the battery voltage or temperature exceeds the range approved by the manufacturer, charging is prohibited. 

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