All about lithium batteries

Introduction of lithium-ion batteries

Time:2004-9-23 14:32:12 Source:China Battery Network

One, lithium-ion battery name introduction

Lithium-ion batteries are now widely used by all of us is the development of lithium batteries. So before recognizing lithium-ion batteries, let's introduce lithium batteries.

For example, the button cell used in cameras is a lithium battery. The anode material of lithium battery is lithium metal, and the positive material is carbon. According to the customary naming convention, we call this kind of battery lithium battery.

Lithium-ion batteries are made of lithium cobalt oxide and carbon. Battery through the positive electrode generated lithium ions in the negative electrode carbon material embedded and move out to realize the battery charging and discharging process, in order to distinguish it from the traditional sense of lithium batteries, so people call it lithium-ion batteries.

Second, lithium-ion batteries are widely used

The purpose of the development of high-tech is to make it better to serve mankind. Lithium-ion batteries since its inception in 1990, due to its excellent performance has been rapid development, and widely used in society. Lithium-ion batteries have rapidly occupied many fields with the incomparable advantages of other batteries, such as the well-known cell phones, laptop computers, small video cameras and so on, and more and more countries are applying the battery to military use. Application shows that the lithium-ion battery is an ideal small green power.

Three, the main components of lithium-ion batteries

(1) battery cover

(2) positive ---- active material for lithium cobalt oxide

(3) diaphragm ---- a special composite film

(4) negative ---- active material for carbon

(5) organic electrolyte

(6) battery

Four, lithium-ion batteries superior performance

We often say that the superiority of lithium-ion batteries is for the traditional nickel-cadmium batteries (Ni/Cd) and nickel-metal hydride batteries (Ni/MH) to speak. So what is so great about lithium-ion batteries?

(1) High operating voltage

(2) High specific energy

(3) Long cycle life

(4) Low self-discharge rate

(5) No memory effect

(6) Pollution-free

The following is a comparison of the performance of nickel-cadmium, nickel-metal hydride and lithium-ion batteries:

Technical parameters Nickel-cadmium batteries Nickel-metal hydride batteries Lithium-ion batteries

Operating voltage (V) 1.2 1.2 3.6

Weight specific energy (Wh/Kg) 50 65 105-140

Volume specific energy (Wh/l) 150 200 300

Charge and discharge life (times) 500 500 1000

Self-discharge rate (%/month) 25-30 30-35 6-9

Is there any memory effect Yes Yes No

Is there any pollution Yes No No

(Note: Charge rate are 1C)

Fifth, the working principle of lithium-ion batteries

Everyone already knows that the positive electrode material of lithium-ion batteries is lithium cobalt oxide, and the negative electrode is carbon. The working principle of lithium-ion battery means its charging and discharging principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon as the negative electrode is a layered structure, it has a lot of micropores, the lithium ions that reach the negative electrode are embedded in the micropores of the carbon layer, the more lithium ions are embedded, the higher the charging capacity. By the same token, when the battery is discharged (i.e., the process of using the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions that return to the positive electrode, the higher the discharge capacity. What we usually refer to as battery capacity is the discharge capacity.

It is not difficult to see, in the lithium-ion battery charging and discharging process, lithium ions in the positive → negative → positive state of motion. If we compare the lithium-ion battery image as a rocking chair, rocking chair ends for the battery poles, and lithium ions are like a good sportsman, running back and forth in the rocking chair at both ends. Therefore, experts have given the lithium-ion battery a lovely name rocking chair battery.

Six, lithium-ion battery assembly process

Lithium-ion battery technology is very strict, complex, here can only briefly introduce a few of the main processes.

(1) Pulping

Specialized solvents and bonding agents are used to mix with the powdered positive and negative active substances respectively, and after high-speed mixing and homogenization, the positive and negative substances are made into pulp.

(2) Coating

The made slurry is uniformly coated on the surface of metal foil, dried, and made into positive and negative electrode sheets respectively.

(3) Assembly

Place the positive pole piece - diaphragm - negative pole piece - diaphragm in the order of top to bottom, and then make the core of the battery by winding, and then inject the electrolyte, sealing and other processes, that is to say, the assembly process of the battery is completed, and made into finished batteries.

(4) Formation

Charge and discharge test the finished batteries with special battery charging and discharging equipments, and test every battery to screen out qualified finished batteries to be shipped.

Seven, the safety characteristics of lithium-ion batteries

Lithium-ion batteries have been widely used in people's daily lives, so its safety performance should be the first assessment of lithium-ion batteries. For the assessment of the safety performance of lithium-ion batteries, the international provisions of the very strict standards, a qualified lithium-ion battery in the safety performance should meet the following conditions.

(1) short circuit: no fire, no explosion

(2) overcharge: no fire, no explosion

(3) hot box test: no fire, no explosion (150 ℃ constant temperature for 10min)

(4) pinch: no explosion (with Ф3mm nails to penetrate the battery)

(5) plate impact: no fire, no explosion ( 10kg weight from 1M height). (10kg weight from a height of 1M to the battery)

(6) incineration: no explosion (gas flame grill battery)

eight, lithium-ion battery safety features are how to achieve?

In order to ensure the safe and reliable use of lithium-ion batteries, experts have carried out a very strict, well-thought-out battery safety design to achieve the battery safety assessment indicators.

(1) Diaphragm 135 ℃ automatic shutdown protection

Adopted the international advanced Celgard2300PE-PP-PE three-layer composite film. In the case of the battery heating up to 120 ℃, the PE membrane holes on both sides of the composite membrane closed, the battery internal resistance increased, the battery internal heating slowed down, the battery heating up to 135 ℃, PP membrane holes closed, the battery internal disconnection, the battery is no longer warmed up, to ensure that the battery is safe and reliable.

(2) Add additives to the electrolyte

In the battery overcharge, the battery voltage is higher than 4.2v conditions, electrolyte additives and electrolyte polymerization of other substances in the battery, the battery internal resistance increased greatly, the battery internal formation of large-area circuit breakers, the battery is no longer warmed up.

(3) Battery cover composite structure

The battery cover adopts a scored explosion-proof structure, when the battery is warmed up, some of the gases generated during the activation process inside the battery will expand, and the internal pressure of the battery will be increased, and the pressure will reach a certain level of scored rupture and outgassing.

(4) Various environmental abuse tests

To carry out various abuse tests, such as external short-circuit, overcharge, pinprick, plate impact, incineration, etc., to examine the safety performance of the battery. At the same time on the battery temperature impact test and vibration, drop, impact and other mechanical performance tests, to examine the performance of the battery in the actual use of the environment.

Nine, lithium-ion battery is a new type of green battery

"Love the environment, protect the Earth" is the responsibility of each of us. How to put our environmental concepts in action to respond to it?

As a battery consumer, we should buy and use new green battery; as a battery manufacturer, we should produce new green battery. Only through everyone's **** with efforts to create, protect our beautiful and harmonious natural environment.

The new green battery is a high-performance, non-polluting battery that has been put into use or is being developed in recent years. Currently has been used in large quantities of lithium-ion batteries, nickel metal hydride batteries and are promoting the use of non-mercury alkaline zinc-manganese batteries, as well as research and development of lithium or lithium-ion plastic batteries, fuel cells, electrochemical storage supercapacitors belong to the category of new green battery. In addition, the use of solar energy for photovoltaic conversion of solar cells (also known as photovoltaic power generation), which has been widely used, also belongs to this category.

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What is a lithium-ion battery

Lithium-ion batteries, commonly known as "lithium-ion", are currently the best overall battery system. Lithium-ion battery anode is a carbon material, such as graphite. The positive electrode is a transition metal oxide containing lithium, such as LiMn2O4.

Lithium-ion batteries have the following advantages:

1. High operating voltage. The operating voltage of lithium-ion batteries is 3.6V, which is three times the operating voltage of nickel-cadmium and nickel-metal hydride batteries.

2. High specific energy. Lithium-ion battery specific energy has reached 140Wh / kg, is three times the nickel-cadmium batteries, nickel-metal hydride batteries 1.5 times.

3. Long cycle life. Currently, the cycle life of lithium-ion batteries has reached more than 1,000 times, in the low discharge depth of up to tens of thousands of times, more than several other secondary batteries.

4. Small self-discharge. Lithium-ion battery monthly self-discharge rate of only 6% -8%, much lower than nickel-cadmium batteries (25-30%) and nickel-metal hydride batteries (30-40%).

5. No memory effect. It can be recharged at any time according to the requirements without reducing the performance of the battery.

6. No pollution to the environment. Lithium-ion batteries do not exist in the harmful substances, is a real "green battery".

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Lithium-ion batteries

Lithium-ion batteries are a kind of high-energy-density batteries made of lithium-ion batteries. Li-ion battery is also a smart battery, which can work with the special original smart charger to achieve the shortest charging time, maximum life cycle and maximum capacity. Lithium-ion batteries are the best performing batteries available. Compared with nickel cadmium batteries and nickel metal hydride batteries of the same size, it has the largest power reserve, the lightest weight, the longest lifespan, the shortest charging time and no memory effect.

News Entry: cmonline Responsibility: cmonline

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What is a lithium-ion battery

Lithium-ion batteries are commonly known as "lithium batteries". ", is currently the best comprehensive performance of the battery system. Lithium-ion battery anode is a carbon material, such as graphite. Positive electrode is a transition metal oxide containing lithium, such as LiMn2O4.

Lithium-ion batteries have the following advantages:

1. High operating voltage, lithium-ion batteries work at a voltage of 3.6V, which is three times that of nickel-cadmium and nickel-metal hydride batteries.

2. High specific energy, lithium-ion battery specific energy has reached 140Wh / kg, is three times the nickel-cadmium batteries, nickel-metal hydride batteries 1.5 times.

3. Long cycle life, lithium-ion battery cycle life has reached more than 1,000 times, in the low discharge depth up to tens of thousands of times, more than several other secondary batteries.

4. Small self-discharge, lithium-ion battery monthly self-discharge rate of only 6-8%, much lower than nickel-cadmium batteries (25-30%) and nickel-metal hydride batteries (30-40%). 5. No memory effect, can be charged at any time according to the requirements, without reducing the performance of the battery.

6. No pollution of the environment, lithium-ion batteries do not exist in the harmful substances, is a real "green battery".

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