Which is better, lithium battery, graphene battery or lead-acid battery?

With the popularity of electric vehicles, more and more people begin to pay attention to the battery. The battery is the energy storage warehouse of electric vehicles. Electric vehicles convert electric energy into chemical energy when charging and store it in the battery. When using electric vehicles, the motor converts the chemical energy in the battery into mechanical energy, so that electric vehicles can run on the road. Since the battery is the power source of electric vehicles, What kinds of batteries are currently used in electric vehicles and which battery is better?

After the rapid development of electric vehicles in recent years, the batteries used in electric vehicles are mainly divided into lithium batteries, graphene batteries and lead-acid batteries. Which is better, lithium batteries, graphene batteries and lead-acid batteries,

Comparison of lithium battery, graphene battery and lead-acid battery

一、 Advantages and disadvantages of lithium battery

1. The energy density is high, and its volume energy density and mass energy density can reach 450W. h/dm3 and 150W. h/kg respectively, and are still increasing.

2. The average output voltage is high (about 3.6V), which is 3 times that of Ni Cd and Ni l batteries.

3. High output power.

4. Self discharge is small, less than 10% per month, less than half of Ni Cd and Ni Ml.

5. Without the memory effect like Ni Cd and Ni MH batteries, the cycle performance is superior.

6. It can be charged and discharged quickly, and the capacity can reach more than 80% of the nominal capacity when charged at 1C.

7. High charging efficiency, basically 100% after the first cycle.

8. The operating temperature range is wide, - 30~+45 ℃. With the improvement of electrolyte and positive electrode, it is expected to be widened to - 40~+70 ℃, and the low temperature may be extended to - 60 ℃.

9. No maintenance required.

10. It is "friendly" to the environment and is called green battery.

11. Long service life, 100% DOD can be charged and discharged for more than 900 times; When using shallow depth (30% DOD) charging and discharging, the number of cycles has exceeded 5000.

Disadvantages of lithium battery

1. The cost is high, mainly due to the high price of cathode material LiC002. With the continuous development of cathode technology, LiMn204, LiFeP04, etc. can be used as cathode, which is expected to greatly reduce the cost of lithium ion batteries;

2. There must be special protective circuit to prevent overcharge or overdischarge;

3. The compatibility with ordinary batteries is poor, because lithium ion batteries can be replaced only when three ordinary batteries (3.6V) are used.


二、 Advantages and disadvantages of graphene battery


Graphene battery: Graphene battery is a honeycomb planar film formed by carbon atoms in the way of sp2 hybridization. It is a quasi two-dimensional material with only one atomic layer thickness, so it is also called monoatomic layer graphite. A new energy battery is developed based on the fast and large shuttle motion of lithium ions between graphene surface and electrode.

1. The power storage capacity is three times of the best product on the market at present. The specific energy of a lithium battery (subject to the most advanced) is 180wh/kg, while the specific energy of a graphene battery is more than 600whkg.

2. The electric vehicle powered by this battery can run 1000 kilometers at most, and its charging time is less than 8 minutes.

3. Long service life. Its service life is four times that of traditional hydrogenated battery and twice that of lithium battery.

4. Light weight. The characteristics of graphene can reduce the weight of the battery to half of the traditional battery, which can improve the efficiency of the machine that loads the battery.

5. Graphene has more advantages than traditional batteries. Its service life is twice that of lithium batteries and four times that of hydrogenated batteries.

6. It has faster charging speed and is more durable than lithium battery under high temperature.


Disadvantages of graphene battery:

1. At present, the graphite dilution has not reached the practical stage, and there is still a long way to go before mass production.

2. These graphene batteries in the market are not pure graphene batteries. They are just doped with some graphene related technologies on the basis of lithium batteries. Compared with traditional lithium batteries, the performance improvement brought by them is only a little bit. In addition, the cost of graphene is very high, and its manufacturing process is also very high. The manufacturing process of graphene battery is still not mature enough. At present, it is only in the laboratory stage and cannot reach the level of mass production.

3. Incompatible process characteristics. That is, the excessive specific surface area of graphene will bring a lot of process problems to the dispersion and slurry homogenization of existing lithium ion batteries. If the battery factory adjustment process will be exhausted, and there is not enough profit space driven by the breakthrough progress in performance indicators, who is willing to use this technology? The surface characteristics of graphene are greatly affected by the chemical state, and there are many problems in batch stability, cycle life, etc., which can not meet the detailed requirements of lithium battery production at present.


三、 Advantages and disadvantages of lead-acid battery

Lead acid battery is a kind of battery whose positive and negative poles are mainly made of lead and its oxides, and the electrolyte is sulfuric acid solution. When the lead-acid battery discharges, the main component of the positive pole is lead dioxide, and the main component of the negative pole is lead; During charging, the main components of positive and negative electrodes are lead sulfate.

Advantages of lead-acid battery

1. Cheap price: The lead-acid battery is very cheap because of its low manufacturing cost, simple manufacturing process and low raw material price. In addition, the used lead-acid battery can be recycled, so that the next time the battery is replaced, the old battery can be replaced with a new one, and a part of cash can be offset, reducing the purchase cost.

2. High safety performance: the stability of lead-acid battery is very good, even if it is charged for a long time during use, no explosion and other problems will be found, and the safety performance of lead-acid battery is high.

3. Repairable: Although the lead acid battery may crystallize or sulfurize during use, it can be repaired and can be used for a period of time after repair, so the lead acid battery is repairable, unlike the lithium battery, which cannot be repaired after problems occur.


Disadvantages of lead-acid battery:

1. Large volume and heavy weight: the manufacturing process of lead-acid batteries is a problem. If the capacity of lead-acid batteries is to be increased, it needs larger volume, and the weight will become heavier, making it inconvenient to move.

2. Short service life: The lead acid battery is charged and discharged about 300-350 times, and can be used for about 2-3 years normally.

3. Environmental pollution: Although cadmium is no longer used in lead-acid batteries, it will still cause environmental pollution, such as water pollution and land pollution.

Conclusion: Based on the above comparison of conditions, lithium battery has more advantages than graphene battery and lead-acid battery in terms of maturity of R&D technology, manufacturing cost, market economic benefits and environmental protection.