Lithium Iron Phosphate Batteries

In today's battery market, lithium cobalt oxide batteries, lithium manganese oxide batteries, lithium iron phosphate batteries, and lithium titanate batteries each have their own characteristics, and lithium iron phosphate batteries have been widely used in many fields. The following will provide an in-depth analysis of these four types of batteries.
I. Lithium Cobalt Oxide Batteries

Basic Characteristics

1. The positive electrode material is lithium cobalt oxide (LiCoO₂), and the negative electrode is usually graphite. Its working principle is that during the charging and discharging process, lithium ions move back and forth between the positive and negative electrodes to achieve the storage and release of electrical energy.
2. The nominal voltage is generally relatively high, usually around 3.7V, but the actual output voltage range is between 2.5V and 4.2V.

Advantages:

1. High Energy Density: Lithium cobalt oxide batteries have an extremely high energy density, capable of carrying more electrical energy in the same volume, and can provide higher voltages and currents.
2. Long Cycle Life: They have excellent cycle performance, with normal charging and discharging cycles reaching more than 2,000 times, and a relatively long service life.
3. Good Safety: Although they use flammable metal lithium materials, they have good thermal stability and are not prone to burning or exploding.
4. No Memory Effect: There is no significant voltage change during the charging and discharging process, so there is no need to worry about a reduction in battery capacity due to the memory effect.
5. Low Self-Discharge: They have good self-discharge performance, which is beneficial for maintaining long-term storage performance.
6. Environmentally Friendly: Composed mainly of cobalt and lithium elements, they are less polluting compared to traditional battery materials.

Disadvantages:

1. High Cost: Cobalt is a rare metal with a high price, resulting in high manufacturing costs and expensive lithium cobalt oxide batteries.
2. Limited Charging and Discharging Cycles: Although the cycle life is long, there are still limitations on the number of cycles, and they need to be replaced regularly, increasing the cost of use.
3. Temperature Sensitive: They are prone to overheating in high-temperature environments, with risks of explosion or fire; in low-temperature environments, they are prone to overcharging or overdischarging, leading to battery damage.
4. Long Charging Time: The charging process takes a long time, and it has high requirements for charging voltages and currents, requiring professional chargers.
5. Slow Discharge Rate: Relatively speaking, the discharge rate is slow, which may affect the performance of electronic devices.
6. Environmental Pollution Risk: If not used and stored properly, they may still cause certain pollution to the environment.

Application Fields:

1. Due to their advantages such as high energy density and long cycle life, they are widely used in consumer electronic products (such as mobile phones, notebook computers, etc.), electric vehicles, drones, and other fields. However, their high cost and temperature sensitivity also limit their application in some fields.

II. Lithium Manganese Oxide Batteries

Basic Characteristics:

1. The positive electrode material is lithium manganese oxide (LiMn₂O₄), and the negative electrode is usually graphite. Lithium ions move back and forth between the positive and negative electrodes to complete the charging and discharging process.

Advantages:

1. High Energy Density: They have a relatively high energy density, can provide more electrical energy, making the battery smaller in volume and lighter in weight.
2. Long Cycle Life: They have a long cycle life, can withstand multiple charging and discharging cycles, extending the battery's service life.
3. Wide Operating Temperature Range: They can operate within a wide temperature range, including low-temperature environments, which has an advantage in specific application scenarios.
4. Environmental Protection: As a type of lithium-ion battery, they are environmentally friendly, do not contain toxic and harmful substances, and have little impact on the environment.

Disadvantages:

1. Poor Thermal Stability: They are prone to heating in high-temperature environments, and the positive electrode material is prone to decomposition at high temperatures, reducing safety.
2. Limited Charging and Discharging Rate Performance: They may be limited when charging and discharging quickly.
3. Capacity Attenuation: As the number of charging and discharging cycles increases, the capacity will gradually attenuate, affecting the battery's performance and service life.

Application Scenarios:

1. Due to their characteristics such as high energy density and long cycle life, they are widely used in occasions that require large current discharge and high-power output, such as electric bicycles. At the same time, the cost is relatively low, and they are also suitable for application fields that are sensitive to cost.

III. Lithium Iron Phosphate Batteries

Battery Structure and Working Principle:

1. It is composed of a positive electrode (lithium iron phosphate), a negative electrode (carbon), a separator, and an electrolyte, and is hermetically sealed in a metal shell. The positive electrode is connected to the battery through aluminum foil, and the negative electrode is connected to the battery through copper foil.
2. During charging, some lithium ions in the lithium iron phosphate are removed, transferred through the electrolyte to the negative electrode, and embedded in the carbon material of the negative electrode; at the same time, electrons are released from the positive electrode and reach the negative electrode through the external circuit to maintain the balance of the chemical reaction. The discharging process is the opposite.

Battery Characteristics:

1. High Energy Density: Taking the latest generation of self-developed and self-produced "Blade-type" lithium iron phosphate battery by Geely - the Shendun Short Blade Battery as an example, its energy density reaches 192 Wh/kg.
2. Long Cycle Life: It has a long cycle life, with the 1C cycle life generally reaching more than 2,000 times, and even reaching more than 3,500 times, far exceeding traditional lead-acid batteries.
3. Good Safety Performance: The electrochemical performance of the lithium iron phosphate positive electrode material is stable, the charging and discharging platforms are stable, and the structure is stable, not prone to burning or exploding.
4. Low Self-Discharge Rate: The self-discharge rate is small, and the power loss during storage is small.
5. No Memory Effect: It can be used as needed without having to discharge completely before charging.
6. Wide Operating Temperature Range: It can work normally at lower or higher temperatures.

Application Fields:

1. Due to its excellent performance, it is widely used in new energy vehicles, energy storage systems, electric tools, and other fields. Especially in the new energy vehicle field, due to its high safety, long life, and low cost, it has become one of the important choices for power batteries.

IV. Lithium Titaniate Batteries

Battery Structure and Working Principle:

1. It is composed of a positive electrode, a negative electrode, a separator, and an electrolyte, etc. The positive electrode can adopt materials such as lithium manganese oxide, ternary materials, or lithium iron phosphate, and the negative electrode adopts lithium titanate material.
2. During the charging and discharging process, lithium ions are embedded and de-embedded back and forth between the positive and negative electrodes, accompanied by the transfer of electrons, to achieve the storage and release of electrical energy.

Advantages:

1. High Safety: The potential of lithium titanate is higher than that of pure metal lithium, not prone to generating lithium dendrites, reducing the risk of battery short-circuit.
2. High Stability: The structure is stable during the charging and discharging process, not prone to volume changes, and has good cycle stability.
3. Long Life: The stable structure and high safety make it have a long cycle life.
4. Environmentally Friendly: The lithium titanate material is non-toxic and harmless, and is friendly to the environment.
5. Fast Charging and Discharging Ability: The negative electrode material has a higher lithium-ion diffusion coefficient, capable of fast charging and discharging, satisfying the need for fast charging.

Disadvantages:

1. Low Energy Density: Compared with ternary lithium batteries, lithium iron phosphate batteries, etc., the energy density is lower, limiting its application in occasions with high requirements for energy density.
2. High Price: The cost of the lithium titanate material is high, resulting in a relatively high price of the battery.
3. Gas Generation Problem: Ordinary lithium titanate batteries are prone to gas generation, leading to cell bulging and performance degradation.

The reason why lithium iron phosphate batteries are widely used is mainly because they have characteristics such as high safety, long life, low cost, and environmental friendliness. When choosing a battery, various factors need to be considered comprehensively according to specific application scenarios and usage requirements.