Which is better, nickel-cadmium battery or lithium battery?

There are seven main differences:

1. The constituent materials are different: the lithium battery uses carbon material (graphite) as the negative electrode and lithium-containing compound as the positive electrode; the nickel-cadmium battery positive electrode is composed of active materials such as nickel oxide powder and graphite powder, and the negative electrode is composed of cadmium oxide powder and iron oxide powder composed of the active substance.

2. The working principle is different: lithium battery is more equivalent to a charge container, basically does not rely on electrochemical reaction when working, when charging the battery, 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 has a layered structure, and it has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity. Similarly, when the battery is discharged (ie, the process we use 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 return to the positive electrode, the higher the discharge capacity. The work of nickel-cadmium battery requires electrochemical reaction. When charging, the electrons flow along the wire to the cathode, and the nickel dioxide of the cathode reacts with the water in the sodium hydroxide solution to form nickel hydroxide and hydroxide ions, and the electrical energy is converted into chemical energy; The cadmium (CD) at the negative electrode and the hydroxide ion (OH-) in the sodium hydroxide (NAOH) form cadmium hydroxide and adhere to the anode, and also emit electrons, and the chemical energy is converted into electric energy;

3. Different charge and discharge characteristics: lithium battery has strict control of charge and discharge current, cannot be too large, and the voltage gradually decreases during discharge, the change is large, but the lithium battery charging efficiency is higher, and there is no memory effect; nickel-cadmium battery can be large The current is quickly charged, and it can supply a large current to the load, and the voltage change during discharge is small, but its charging efficiency is low, and the memory effect is serious;

4. Single-cell voltage is different: lithium battery single-section voltage 3.6v or 3.7v, nickel-cadmium battery single section 1.2v;

5. Different durability characteristics: lithium battery is more delicate, over-discharge or over-charge will cause permanent damage, so you need to install a protective circuit board, and need to charge and discharge maintenance once every six months or so; nickel-cadmium battery can withstand over-charging or over-discharge The operation is simple and convenient, and the performance is not deteriorated after being placed for a long time, and the original characteristics can be restored when the battery is fully charged;

6. The power volume ratio is different: lithium battery power volume is relatively high, the same weight, volume can store more electricity than nickel-cadmium batteries;

7. Different environmental protection characteristics: Cadmium in nickel-cadmium batteries is toxic, so nickel-cadmium batteries are not conducive to the protection of the ecological environment. Numerous shortcomings have made nickel-cadmium batteries have been eliminated from the application range of digital equipment batteries. Lithium batteries are basically free of toxic elements and have little impact on the environment, so they are widely used in digital electronic devices.

The lithium battery has a single voltage of 3.2 and 3.7V, and a single nickel-hydrogen battery of 1.2V. A lithium iron phosphate battery with a single voltage of 3.2V (above) a single lithium-ion battery with a voltage of 3.7V (above)

A single-voltage 1.2V nickel-metal hydride battery (above)

Lithium batteries have no memory effect, and nickel-metal hydride batteries have a memory effect.

Lithium batteries do not contain heavy metals (cadmium).

The manufacturing and use of lithium batteries is environmentally friendly and pollution-free.

The specific capacity of a lithium battery is high, and the specific capacity is electric energy (wh) per unit volume and weight.

The price of a lithium battery unit is high.

Lithium batteries have a long cycle life.

8. Lithium batteries are more specific than nickel-metal hydride batteries in terms of specifications and less universal. For example, nickel-metal hydride batteries (AA) and nickel-metal hydride batteries (AAA) can be replaced by carbon batteries (AA) or alkaline batteries (AA) and carbon batteries (AAA).

NIMH battery advantages

1, overcharged and overcharged,

2, high-speed discharge capability,

3, safe use, especially under abuse conditions;

4, relatively cheap;

5, high power density

Disadvantages, low voltage and low energy density

The main advantages of lithium batteries:

The lithium battery voltage platform is high: the average voltage of the single battery is 3.7V or 3.2V, which is equal to the series voltage of three nickel-cadmium batteries or nickel-hydrogen batteries, which is convenient for forming a battery power pack;

The lithium battery has a high energy density relative to the battery. With high storage energy density, it has reached 460-600Wh/kg, which is about 6-7 times of lead-acid battery;

Compared with lead-acid batteries, lithium batteries are light in weight, and the weight in the same volume is about 1/5-6 of that of lead-acid products;

Lithium battery has a relatively long service life, and the service life can reach more than 6 years. The battery with lithium iron phosphate as the positive electrode is charged and discharged with 1CDOD, and there are 1000 records that can be used;

With high power bearing capacity, lithium iron phosphate lithium ion battery for electric vehicles can achieve 15-30C charge and discharge capacity, which is convenient for high-intensity start-up acceleration;

Low self-discharge rate, no memory effect;

The lithium battery has high adaptability to high and low temperature, and can be used in the environment of -20 ° C - 60 ° C. After the process treatment, it can be used in the environment of -45 ° C;

It is green and environment-friendly. No matter it is produced, used or discarded. It does not contain or produce any toxic and harmful heavy metal elements and substances such as lead, mercury and cadmium.

Disadvantages of lithium batteries:

1. Lithium batteries have poor safety and there is a danger of explosion.

2. The lithium battery of lithium cobalt oxide material cannot discharge at a large current, and the safety is poor.

3. Lithium batteries need to protect the line to prevent the battery from being overcharged and discharged.

4. High production requirements and high cost.

Advantages of polymer lithium battery:

1. The working voltage of the single battery is as high as 3.6v~3.8v, which is much higher than the 1.2V voltage of Ni-MH and Ni-CD batteries.

2. The capacity density is large, and the capacity density is 1.5~2.5 times or higher for the nickel-hydrogen battery or the nickel-cadmium battery.

3. Self-discharge is small, and its capacity loss is small after being placed for a long time.

4. Long life, normal use of its cycle life can reach more than 500 times.

5. No memory effect, do not have to empty the remaining power before charging, easy to use.

6. Good safety performance

Disadvantages of polymer lithium batteries:

1. The battery cost is high and the electrolyte system is difficult to purify.

2. It need to protect the line control, overcharge or over discharge will cause the reversibility of the internal chemical substances of the battery to be destroyed, thus seriously affecting the life of the battery.

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