The difference between iron lithium battery and lithium battery

The iron-lithium battery is a kind of battery in the lithium battery family, and the positive electrode material is mainly lithium iron phosphate material, which is also referred to as iron lithium battery. Compared with traditional lead-acid batteries, lithium-ion batteries have significant advantages in terms of operating voltage, energy density, and cycle life.

Compared with the traditional lead-acid battery, the iron-lithium battery has the following advantages: high energy density, high safety, high temperature performance, high power output and long cycle life, light weight, saving room reinforcement cost, small size, long battery life, Good security and other advantages.

In 1990, Sony first introduced lithium-ion batteries with LiCoO2 as a positive electrode in the laboratory, and began industrial production in 1991. Compared with traditional lead-acid batteries lithium-ion batteries have significant advantages in terms of operating voltage, energy density, and cycle life. Therefore, lithium ion batteries have been widely used in portable electronic devices and power tools for the past two decades. In recent years, with the global attention to energy conservation and emission reduction, lithium-ion batteries have gradually been used in various industries such as communications, national power grids and electric vehicles. For the energy-saving and emission reduction of the communication power industry, the battery is required to be smaller in size, lighter in weight, longer in life, more resistant to high temperatures, easier to maintain, more stable in performance, more environmentally friendly, etc. Therefore, in order to meet these demands, lithium-ion batteries are also required. It is gradually shifting to the direction of large-capacity batteries, and lithium iron phosphate batteries for communication have emerged. The abc iron-lithium battery is a type of battery in the lithium battery family. The positive electrode material is mainly lithium iron phosphate material. It is also referred to as iron lithium battery.

Iron-lithium batteries are not as safe as some friends on the Internet say. There is also the danger of an explosion. Technology requires truthfulness and rigor.

The lithium iron phosphate battery 26650-3AH was overcharged by 3C10V, and the battery exploded. Repeat the test and the results are similar.

When the lithium battery is charged and discharged at a large current, the inside of the battery continues to heat up, and the gas generated during the activation process expands, the internal pressure of the battery increases, and the pressure reaches a certain level. If the outer casing has a flaw, it will rupture, causing liquid leakage, fire, and even explosion. Therefore, when you use it, you must pay attention to safety.

However, during normal use, the battery management system is generally used to protect the power lithium battery, so there is almost no explosion. However, for mobile phone batteries, because the protection measures are not in place, it is more likely to explode.

The full name of the iron-lithium battery is lithium iron phosphate lithium-ion battery. Because its performance is particularly suitable for power applications, it is also called "lithium-iron power battery". (Hereinafter referred to as "Iron Lithium Battery")

Working principle of iron-lithium battery (LiFePO4)

The internal structure of the LiFePO4 battery is shown in Figure 1. On the left is the olivine-structured LiFePO4 as the positive electrode of the battery. The aluminum foil is connected to the positive electrode of the battery. The middle is the polymer separator. It separates the positive electrode from the negative electrode, but the lithium ion Li+ can pass and the electron e- cannot pass. The right side is composed of A battery negative electrode composed of carbon (graphite) is connected to the negative electrode of the battery by a copper foil. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.

When the LiFePO4 battery is charged, the lithium ion Li+ in the positive electrode migrates toward the negative electrode through the polymer separator; during the discharge, the lithium ion Li+ in the negative electrode migrates toward the positive electrode through the separator. Lithium-ion batteries are named after the lithium ions migrate back and forth during charging and discharging.

LiFePO4 battery main performance

The nominal voltage of the LiFePO4 battery is 3.2V, the termination charging voltage is 3.6V, and the termination discharge voltage is 2.0V. Due to the quality and process of the positive and negative materials and electrolyte materials used by various manufacturers, there will be some differences in their performance. For example, the same model (standard battery of the same package) has a large difference in battery capacity (10% to 20%).

lithium iron phosphate battery is actually a lithium ion battery with lithium iron phosphate as the positive electrode material. For lithium ion battery, the positive electrode data is divided into various kinds such as lithium cobaltate, lithium manganate, lithium nickelate, ternary data and iron phosphate. Lithium, etc., during which lithium iron phosphate is the most commonly used material in the lithium battery industry.

The lithium iron phosphate battery is connected by the aluminum foil to the positive electrode of the battery, and the left side is the barrier of the polymer. It separates the positive electrode from the negative electrode, but the lithium ion Li can be started and the electron e- cannot be used. The right side is the negative electrode of the battery composed of carbon. It is connected with the negative pole of the battery. The electrolyte is sealed between the upper and lower ends of the battery. The battery is sealed by a metal casing. When the LiFePO4 battery is charged, the lithium ion in the positive electrode is separated from the polymer to the negative electrode. During the discharge process, the negative electrode lithium ion Li in the beginning is moved to the positive electrode and the lithium ion battery is named after the lithium ion is moved back and forth during charging and discharging.

Lithium-ion battery operation principle, when the battery is charged, Li moves from the 010 surface of the lithium iron phosphate crystal to the crystal appearance, and under the effect of the electric field force, enters the electrolyte, passes through the barrier, and then moves to the appearance of the graphite crystal through the electrolyte. Then embedded in the graphite lattice, after lithium ions are deintercalated from lithium iron phosphate, lithium iron phosphate is converted into iron phosphate; when the battery is discharged, Li is deintercalated from the graphite crystal, enters the electrolyte, passes through the barrier, and then passes through the electrolyte. Moved to the appearance of the lithium iron phosphate crystal, and then re-inserted into the crystal lattice of lithium iron phosphate via the 010 surface, and then discharged to the lithium iron phosphate positive electrode through the electric conductor to start discharging.

In order to align the conduction of the positive and negative electrodes of the lithium iron phosphate battery, it is necessary to participate in the positive and negative electrodes of the battery to make it constitute the activity of the battery, and how to end in the process of theoretical depiction and the theoretical production process. The above three equations also need to describe a series of experiments to verify, establish a mathematical model or establish a curriculum vitae formula, and then these models may be formulated for lithium-ion battery depiction.

At that time, the domestic lithium-ion battery skills were old enough to have the world's leading level. At that time, the industry was still focusing on lithium-ion batteries with lithium iron phosphate as the positive electrode. Many countries have developed new lithium-ion battery materials, only at that time, there was no large-scale production. Some scholars pointed out that at least within 10, the lithium iron phosphate cathode data is an open mainstream industry.

1, Typical voltage of lithium iron phosphate monomer is 3.2V; lithium ion 3.7V

2, lithium iron phosphate puncture does not fire without explosion; lithium ions will.

3, lithium iron phosphate resistant to over-charge to 100% will not cause a fire explosion; lithium ion more than 4.35V will be gassing bulging.

4, lithium iron phosphate resistant to overcharge and over discharge, short-term over-release to 0 can recover more than 80%; lithium ions over-discharge to 2.6V will produce irreversible damage.

5, lithium iron phosphate battery refers to a lithium ion battery using lithium iron phosphate as a positive electrode material. The positive electrode materials of lithium ion batteries mainly include lithium cobaltate, lithium manganate, lithium nickelate, ternary materials, lithium iron phosphate and the like. Among them, lithium cobaltate is the positive electrode material used in most lithium ion batteries.

6, improvement of safety performance

The PO bond in the lithium iron phosphate crystal is stable and difficult to decompose, and does not collapse or heat like a lithium cobaltate or form a strong oxidizing substance even at a high temperature or overcharge, and thus has good safety. It has been reported that in the actual operation, a small part of the sample was found to have a burning phenomenon in the acupuncture or short-circuit test, but there was no explosion event. In the overcharge experiment, a high-voltage charge that was several times higher than the self-discharge voltage was used, and it was found that there was still explosion phenomenon. Nevertheless, its overcharge safety has been greatly improved compared to the ordinary liquid electrolyte lithium cobalt oxide battery.

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