Lithium Batteries Knowledge
Against the background of energy crisis and environmental pollution, lithium-ion batteries, as an ideal energy source for development in the 21st century, have received more and more attention. However, some failure phenomena may occur in the production, transportation, and use of lithium-ion batteries. Moreover, the failure of a single battery will affect the performance and reliability of the entire battery pack, and even cause the battery pack to stop working or other safety issues.
Lithium-ion battery has a high energy density, its capacity is 1.5 to 2 times that of a nickel-hydrogen battery of the same weight, and it has a very low self-discharge rate. In addition, lithium-ion batteries have almost no "memory effect" and do not contain toxic substances. These advantages of lithium-ion batteries make it widely used in the field of new energy vehicles.
Nowadays, the more widely used cylindrical lithium-ion batteries are 18650 batteries and 21700 batteries.
Lithium-ion batteries and lead-acid batteries are currently the two most widely used batteries. So what is the difference between these two batteries and which one is better? The following will focus on the difference between lithium-ion batteries and lead-acid batteries.
For lithium batteries, our focus is often on capacity and energy density. These data can usually directly reflect the length of the battery's cruising range. But what we should note is that most lithium batteries are the products of electrochemistry. Since they are related to chemistry, their performance has a great relationship with temperature.
The self-discharge reaction of lithium-ion batteries is inevitable, and its existence not only leads to the reduction of the battery's own capacity, but also seriously affects the battery's configuration and cycle life. The self-discharge rate of lithium-ion batteries is generally 2% to 5% per month, which can fully meet the requirements for the use of single batteries.
Ternary lithium ion battery refers to a lithium ion battery that uses three transition metal oxides of nickel, cobalt, and manganese as the positive electrode material. Because it combines the advantages of lithium cobalt oxide, lithium nickel oxide and lithium manganate, it has excellent performance for any of the above single-component cathode materials.
The 18650 type lithium battery is a more commonly used lithium battery in electronic products, and is often used as a cell in the battery pack of a notebook computer. When we use it, we find that sometimes the 18650 lithium battery cannot be charged. Let's analyze the reason below.
The lithium battery protection circuit board is mainly composed of protection IC (overvoltage protection) and MOS tube (overcurrent protection), and is a device used to protect the safety of lithium battery cells. Lithium batteries are widely used by people for their large discharge current, low internal resistance, long life, and no memory effect. Lithium-ion batteries are strictly prohibited from overcharging, overdischarging, and short-circuiting during use, otherwise it will cause the battery to catch fire and explode. Therefore, when using rechargeable lithium batteries, there will be a protective circuit board to protect the safety of the batteries.
18650 is a lithium-ion battery is a standard lithium-ion battery model set by the Japanese SONY company in order to save costs, where 18 represents a diameter of 18mm, 65 represents a length of 65mm, and 0 represents a cylindrical battery. The battery pack assembled by two or more 18650 cells in series or in parallel is collectively called the 18650 battery pack.
As we all know, the high-temperature performance of lithium iron phosphate battery packs is very good, the peak heat can reach 350～500℃, and it can still release 100% capacity at high temperature (60℃). But the low temperature is a bit worse than other battery systems, so how to improve its low temperature performance?