1. Is safety the most important thing for batteries?
Yes, there are no security measures. All functions are in the water moon. In fact, lithium batteries can be put into use because their safety has reached a level acceptable to the public.
For current battery products, "lithium battery" is not a very correct name. I have explained this many times when the Nobel Prize in Chemistry was awarded in 2019. The "lithium batteries" we commonly use now are actually "lithium ion batteries", while real lithium batteries are only used in some special occasions. The difference in principle between the two is still very large. Lithium-ion batteries basically form currents by flowing lithium ions from a high concentration environment to a low concentration environment. This type of battery is a concentration difference battery, while lithium batteries use metal lithium as the negative electrode, and form current through redox reaction, which is the same as the principle of ordinary zinc-manganese dry batteries. The energy density of
lithium batteries is much higher than that of lithium-ion batteries, but the number of cycles is lower. However, in life, there are almost only lithium-ion batteries, but no lithium-ion batteries. The core reason is that lithium batteries are very unsafe because metal lithium can react with water and oxygen, then heat it up, which eventually leads to an explosion. The public may think that lithium-ion batteries are unsafe, and they explode every once in a while, but if we actually use lithium batteries, the accident is not enough for us to see now. It is precisely because of poor safety that the cost of developing special lithium batteries is shocking. In order to design a special lithium battery, the factory needs to turn on the dehumidifier completely, and the daily electricity bill is nearly 30,000 yuan. Even so, the output is still very low. Thousands of small batteries are produced every day, and the production cost per watt-hour is as high as about 20 yuan. In contrast, the production cost of traditional lithium-ion batteries does not exceed 1 yuan.
Therefore, safety is life. Without life, you won’t make money. The price you pay for safety is amazing. Although lithium-ion batteries have safety problems, they do not threaten their huge value, so they can be widely used.
2. Is lead-acid battery safe?
is safe according to the standards of lithium-ion batteries. For example, many lithium-ion batteries cannot be broken down. If the needle falls, the battery will burst, but lead acid won't have this problem.
This is because lithium-ion batteries usually contain combustible electrolytes, to be precise, conductive salts and combustible solvents, including carbonates, ethers, esters, etc. Once the battery is pierced, the positive and negative electrodes are directly connected, and a short circuit occurs. The battery will be discharged quickly, the solvent will be ignited, which may eventually lead to an explosion. The specific principles are not clear in one or two sentences. If you want to know more, it is recommended to start with the basic structure of the battery.
Of course, there is no problem with lead-acid battery. Its electrolyte is sulfuric acid. I learned specific principles in middle school. Therefore, it makes sense to say that acupuncture is safe, but if we really use needles to prick the lead-acid battery, would we think it is safe?
obviously isn't. Is sulfuric acid leakage safe? In addition, during normal use, lead-acid batteries will release sulfur-containing gas, and some sulfuric acid will be reduced to sulfur dioxide, which is also toxic. This doesn't matter on land, but think about it. On underwater boats, these toxic gases cannot be released. what happens?
Therefore, whether the lead-acid battery is safe depends entirely on the lithium-ion battery, but its safety is not as high as expected. Security is more than just one dimension. When a lithium-ion battery is pierced, it will explode, and when a lead-acid battery is pierced, it will be corrosive. These are all unsafe factors, but the explosion has a greater impact on vision.
3. Is lithium-ion batteries safe?
Of course
At present, lithium-ion batteries usually add flame retardants to prevent the electrolyte from burning due to short circuits and other reasons, which solves safety problems to a certain extent.
Of course, there is a more direct way to completely avoid combustion and explosion using solid electrolytes.
We recently conducted a puncture test on the battery at a third-party testing agency.
It can be seen that the fully charged battery did not respond after acupuncture.
I cannot provide more information due to confidentiality requirements in sensitive industries, but in fact, the battery has also passed tests such as drops, squeezing, etc., but it is not the safest one. There is also one that can be thrown into the oven, and you can imagine what they are for.The question for
is now, why do we think lithium-ion batteries are very unsafe and prone to explosion?
Fires and explosions on mobile phones and cars in previous years were indeed impressive. Even industry insiders know some accidents in energy storage power stations, but electric bicycles are really adding fuel to the fire.
During these two days, due to the hot floods in Wu Yifan and Henan, the tragedy of electric bicycles in Hangzhou may not be noticed. Post a link: a loud bang! An electric car caught fire while driving in Hangzhou. Dad and daughter were surrounded by a fire brigade! Ten seconds later, a group of people rushed over. . . This accident was very miserable and even more serious than the elevator accident in Chengdu.
In terms of accident rates, electric bicycles are much higher than mobile phones and new energy vehicles, and most mobile phones and cars catch fire while charging. People may not be on site, but electric bikes often catch fires during use.
This is mainly due to cost compression. Take the Hangzhou accident as an example. The battery of the electric bicycle has been replaced and the price is only 500 yuan. Generally speaking, the battery used by electric bicycles is 48 volts and 20 ampere hours, and the energy is 960 watt hours, which is close to 1 kWh. The production cost of lithium-ion batteries in general enterprises can be reduced to about 0.5 yuan per watt-hour. Therefore, if this battery is produced by a regular manufacturer, the minimum cost of the photocell is RMB 500. In addition, the battery management system, housing, wires, sales expenses and profits can all be controlled at around 1,000 yuan, which is very low. In fact, it is normal to sell it for around 1,500 yuan. So, what is the source of the 500 yuan battery?
I want to say some details here, but I think this might incite criminals to find ways to make money, so I will forget about it. Gray industrial chain? Brain nourishing is good.
4. Since lithium-ion batteries are very likely to explode due to cost control, why not use cheaper lead-acid batteries instead?
OK, the core of the problem.
Many people don’t understand: Because lithium-ion batteries are too expensive, some people cut corners, so they are prone to catch fire. Isn't it good to just use lead-acid batteries?
This is not impossible, but consumers do not pay.
The new national standard of electric bicycles is indeed a factor, but it is worth noting that compared with the old national standard, the weight requirement of electric bicycles has increased from no more than 40 kg to no more than 55 kg, which can be said to be a greatly relaxed. The 960 watt-hour battery mentioned above is an example. It is made of lead-acid batteries and weighs about 20 kg. It's really heavy, and the lithium-ion battery weighs about 8 kg. If the lithium-ion battery can reach 40 kg for the whole vehicle, it will not be difficult for the lead-acid battery to reach 55 kg. This is not a technical issue.
The question is, is there anyone willing to run back and forth in the car with a 20kg battery all day? It's very heavy to ride. If you need to remove it to charge, it's really manual.
Therefore, at least in the field of electric bicycles, lead-acid batteries have been eliminated by the market, and the advantage of cheapness cannot offset the actual demand for lightweighting.
As for the automotive field, lead-acid batteries were proven to be unsuitable for electric vehicles more than 100 years ago. When Edison made electric cars, he still used iron-nickel batteries. At that time, the battery life was over 200 kilometers, comparable to some electric car manufacturers that were not in a hurry to make progress. For more than 100 years, he has been crushed to the ground by a gasoline car. How are lead-acid batteries used?
In fact, even some of the most concerned scenes of weight problems are considering replacing lithium-ion batteries. For example, underwater ships need to increase counterweight, and lead-acid batteries are very suitable. But now, ships have more and more functions, lead-acid batteries have become a burden, and lithium-ion batteries have also begun to receive attention.
Finally, let's summarize. The safety of lithium-ion batteries is not as low as expected, and lead-acid batteries are not as high as expected. On the one hand, the insecurity of lithium-ion batteries is a technical issue that can be improved; on the other hand, this is a cost control issue that depends on human nature. Replacing lead-acid batteries with lithium-ion batteries is mainly a market behavior.
