The voltage rise will bring two biggest problems: safety and difficulty in the design of electrical components. However, DC is more dangerous than AC with the same voltage. Different countries have different laws and regulations. Generally, DC power less than or equal to 36V or 48V is considered as safe voltage, and over 60V voltage can cause harm to human body. In EU electrical regulations, products above 48V require additional electrical safety certification. Low pressure is recommended.

Precautions for battery replacement of electric vehicle:

1. In the process of electric vehicle license plate or battery replacement, some illegal vendors in order to save costs, steal the battery or charger, so that consumer products have potential safety risks, which will have to go to the regular manufacturers with credibility to replace and purchase.

Check whether the electric vehicle battery product marks are complete, including the manufacturer name, product specification and model, manufacturing date and trademark; check whether the internal and external marks are consistent, especially whether the product body has eye-catching identification and production date. Appearance of electric vehicle battery. Check whether there is deformation, crack, scratch and leakage trace. The battery terminal should be clean and free of rust, and the mark should be clear.

2. The battery model matches the electric vehicle,

It is feasible to replace the lead-acid battery and lithium battery with the same capacity and voltage. However, it is necessary to consider whether the size of the battery can still be installed in the original position, and whether it protrudes or is squeezed, because extrusion and damp will damage the internal part of the battery and cause short circuit. In addition, the voltage should be matched with the battery motor.

3. Battery brand model mismatch

The brand model registered on the electric vehicle certificate does not match the brand and model of the battery used in the electric vehicle. There is the possibility of replacing the original battery with the inferior one or using the renovated battery instead of the original battery, which is easy to cause spontaneous combustion and other hidden dangers.

4. Chargers that match the battery type must be used

The capacity and voltage of lead-acid battery and lithium battery are the same, so the charger should not be used indiscriminately, because the charging voltage and current of the two batteries are not equal in each stage. Therefore, choose and purchase the battery matching, with automatic control of intelligent charger. When the lead-acid battery is charged, the charger voltage is high. The lithium battery has high technical requirements, so when charging, the charger adopts constant current and constant voltage charging. Lead acid charging lithium battery will lead to overcharge and explosion risk.

5. When buying electric vehicles, you must check whether they are in the catalogue of electric bicycles. Do not buy illegally assembled electric vehicles for cheap prices.

6. Do not illegally refit electric vehicles

The birth of lithium batteries began with the discovery of "lithium". In 1817, Swedish chemist chemistry first extracted lithium from a mineral sample from a Swedish island. The name of lithium is inspired by the Greek stone and stone. Although it sounds "heavy", it is actually the lightest solid element known so far.

The chemical periodic table must have been very familiar when you were in middle school. From the chemical periodic table, we can know that the relative atomic mass of lithium is, belonging to the first group or the second cycle. It is the most active metal among the known elements (including radioactive elements). When I was in high school, my teacher did an experiment. When I threw a piece of lithium in water or burst into the air, it would burn quickly.

Lithium is so unstable, how can it become an indispensable lithium battery in modern life?

In order to be a good energy carrier, it is necessary to store and carry more energy with the smallest volume and weight as possible. From lithium element to lithium battery, it is due to the three characteristics of lithium battery

1: The relative mass of lithium atom is small

2: Strong electronic capability

3: High electron transfer ratio

These three points can be concluded in the periodic table of elements. The elements on the top of the periodic table are better than the elements below, and the elements on the left are better than those on the right. Of course, some people will say that hydrogen should not be the best energy carrier? Of course, I don't deny that hydrogen is the best energy carrier in nature. Otherwise, why is the research on hydrogen fuel cells in the ascendant? Hydrogen can only be said to be the development frontier in the future, and the current technology is not mature.

So the choice of lithium as a battery is based on the relative optimal solution we can find among all the elements on earth.

Advantages of lithium battery (analysis based on mobile phone and electric vehicle)

1. High energy. Small size and large capacity. Take mobile phone as an example, the battery of such a small size can store a large capacity of 4000mAh.

2. With long service life, the mobile phone needs to be charged every night, and the number of charge and discharge is very large, but the lithium battery can achieve more than thousands of times of charging and discharging.

3. High rated voltage, single working voltage of or, suitable for the use of small electrical appliances.

4. With high power bearing capacity, lithium iron phosphate lithium-ion battery can reach 15-30c charge and discharge capacity, which is convenient for electric vehicles to achieve high-intensity start-up acceleration, which is the reason why the 100 meter acceleration of electric vehicles is generally very fast.

5. The self discharge rate is very low, generally can be less than 1% / month. When the mobile phone is off, there will be electricity for a long time.

6. It's light, it makes mobile phones easier to carry, and it can make electric cars lighter and faster.

7. High and low temperature adaptability, it can be used in the environment of - 20 ℃ - 60 ℃, basically in line with our living temperature (this is why the mobile phone will be frozen off when it is below - 30 ° in Northeast China)

Based on these seven advantages, lithium battery can be so popular in life. Tesla, a big electric car maker, is making environmentally friendly cars with lithium batteries. Battery manufacturers use lithium batteries to make devices portable.

The purpose of the Nobel Prize is to award the world's people who have made the most important contributions to human beings in the fields of physics, chemistry, physiology or medicine, literature, peace and economics.

Nowadays, we can carry a mobile phone weighing less than 150g to go shopping.

Lithium batteries are not perfect. Take mobile devices as an example. At present, the volume of lithium batteries has been compressed to the extreme. In the tiny space of mobile phones, how to achieve small volume and large capacity, and when the mobile phone can be charged once a month, will be solved one by one in the future. For example, the nuclear fission technology can make a major breakthrough in the next few decades, and can be miniaturized or even micro sized Therefore, the portable nuclear fuel cell will have broad development space.

However, it is undeniable that lithium batteries have made great contributions to human beings in the field of chemistry, and lithium batteries are still the best choice among portable batteries.