For the gift, start research and development of graphene batteries

Chapter 74 Thermal Runaway Must Be Controlled

"Old Wang, organize a meeting to discuss and solve the problem of acupuncture. Other test items are also suspended."

Jiang Ming took the initiative at this moment, and then said to Wang Mingyang.

Seeing Jiang Ming like this, Wang Mingyang wanted to say something, but seeing Jiang Ming's expression, Wang Mingyang didn't speak in the end.

According to Wang Mingyang, since the energy density of the battery cell has reached this level, it is worthwhile for the corresponding safety to be affected a little.

You know, even a 300Wh/kg ternary battery cannot pass the acupuncture test.What's more, carbon-based batteries are products known for their high energy density.

The ternary battery was not used normally, and then became a mainstream product.

Besides, carbon-based batteries have performed well enough, and it is understandable that they persist for so long before they burn up at the end.

With such a long time, it was enough for the passengers to leave safely.

This is not only Wang Mingyang's idea, but also the idea of ​​everyone present.

Jiang Ming took the lead and walked into the conference room. Jiang Ming stood at the front with a serious expression.

Although everyone wondered why Jiang Ming made such a big fuss, Jiang Ming was the deputy chief engineer after all, and the carbon-based battery was designed according to Jiang Ming's intention.

Therefore, everyone still patiently walked into the conference room.

Seeing that everyone was seated, Jiang Ming presided over the meeting.

"Everyone, I want to ask everyone, do you want to solve the problem of battery fire?"

Jiang Ming asked like this.

Hearing Jiang Ming's words, everyone nodded.

Fire is indeed a problem that hinders the development of new energy, and everyone must want to solve it.

But how to put it, thinking is one thing, but being able to do it is another.

Every battery factory has corresponding R&D engineers who are doing this kind of safety development and verification work, but there are only a handful of those who can really succeed in R&D.

Moreover, the successful research and development does not necessarily mean that the probability of battery combustion will be reduced, but it can only be said to be avoided to a certain extent.

As for how much effect it has, I really can't say.

After so many years and doing so much useless work, battery manufacturers no longer have much hope for solving the problem of battery spontaneous combustion in principle.

A more practical method is to start with the assembly of the battery pack to prevent the spread of the ignition point and the extent of early warning.

Such a combination of punches is quite effective.

If it is burned, only a small part will be burned, and there will be no casualties.

People in the industry have already defaulted to the problem of materials. In principle, there is no way to solve it.

"Everyone is an expert in the industry. I know the impact of electric vehicles on fire and the impact on users. To be honest, I am very dissatisfied with the carbon-based battery developed this time!"

Jiang Ming said loudly.

Hearing Jiang Ming's words, there was a commotion in the audience.

After all, except for the failure of the acupuncture test, the performance of the carbon-based battery is epoch-making. This kind of performance is not satisfactory, and everyone is a little confused about what kind of battery Jiang Ming wants.

Is it really necessary to solve the fire problem?

Everyone guessed it right, Jiang Ming was a matter of preparation and fire, and he struggled to the end.

"I'm not satisfied with the carbon-based battery, which failed the needle test."

"You may think that the traditional ternary battery has not passed the acupuncture test, but it still sells well, and it seems that it has no effect."

"Here, what I want to tell you is that it's not the thermal runaway of the battery, we can't control it, it's because we didn't take it seriously."

Hearing Jiang Ming's words, everyone shook their heads for a while, and even Wang Mingyang was a little puzzled by Jiang Ming's words.

"The carbon-based battery must pass the acupuncture test and perform better than lithium iron phosphate."

"You may wonder why carbon-based batteries must pass the acupuncture test. Everyone, when calculating the energy density, have you calculated the energy of a single battery?"

Jiang Ming asked back.

"If you haven't calculated it, let me tell you. Since the energy density of carbon-based batteries is too high, this energy density is already close to the energy density of TNT bombs."

"Think about it, in the product you bought, such a small bomb is installed, and there is a safety risk, aren't you afraid?"

Jiang Ming asked seriously.

This is indeed the case. Before Jiang Ming simply used the traditional ternary battery as a comparison, he thought that acupuncture was not so necessary.

But when Jiang Ming calculated the energy mentioned by the monomer, he realized that the carbon-based battery is no longer a traditional battery. After modification, it definitely has the potential to be a bomb.

Moreover, the acupuncture test of carbon-based batteries is just fine. Once put into the market and used by interested parties, it will be absolutely powerful.

Thinking of the consequences, Jiang Ming was in a cold sweat.

Therefore, Jiang Ming felt that no matter what, he had to solve the problem of spontaneous combustion.

This means that carbon-based batteries will not cause much harm even if they are used by interested parties.

After hearing Jiang Ming's analysis, everyone came to their senses.

This volume, this energy, is indeed worthy of attention.

It's just that although I understand this truth, where to start is also a problem.

In the era of lithium-ion batteries, this problem could not be solved. When it comes to carbon-based batteries, the time is tight and the task is heavy. How can I think about this problem.

If it is said that the only possibility is Jiang Ming.

The next moment, everyone's eyes were on Jiang Ming.

Seeing everyone's eyes, how could Jiang Ming not know what they were thinking, but just wanted to return to his thoughts, and Jiang Ming didn't have a good solution for a while.

If there is a solution, Jiang Ming must have implemented it at the beginning of the design, so why wait until now.

Of course, although there is no such thing for the time being, Jiang Ming believes that as long as he thinks about it seriously and learns from previous research experience, it is still very possible.

"This time gathering everyone, I also want to brainstorm and see if you have any ideas."

Jiang Ming said.

"It's Jiang Ming like this, let me say a few words."

Seeing that Jiang Ming had finished speaking, Wang Mingyang took over and continued.

"I thought it was simple before. I think Chief Engineer Jiang's design concept is very correct. High energy density batteries like carbon-based batteries should indeed solve the problem of spontaneous combustion."

"Even not just spontaneous combustion, including all abnormal use, resulting in thermal runaway, we must avoid it, otherwise, we will suffer a lot in the future."

Wang Mingyang said.

Jiang Ming also has a deep understanding of this. After the launch of carbon-based batteries, it is said that consumers have the most contact with power banks.

In the past, 10000mAh was the most used power bank.If it is replaced with a carbon-based battery, then under the same volume and weight, the capacity of the power bank will increase by about ten times.

In this case, the capacity of the power bank will be increased to 100000mAh.The energy of a single power bank must be 365wh.

General consumers may not understand this energy, but as a technician, Jiang Ming knows that it is really too big.

Once a problem is so large, it is an extremely serious problem and we have to be cautious.

To give a simple example, when flying, charging treasures exceeding 10000mAh are not allowed on board.

Now that the capacity of the battery is ten times larger, once thermal runaway occurs, it is definitely a big deal.

Even if it's not a special occasion, holding such a thing in your hand, if something happens, it's not just a simple matter of burning your hand.

Wang Mingyang's words were very simple. He explained the safety hazards brought about by the high energy density of carbon-based batteries to everyone, and everyone recognized Jiang Ming's point of view.

It's just recognition is recognition, but how to solve practical problems is a difficult problem.

According to the battery design concept, the occurrence of battery thermal runaway can generally be suppressed from the following aspects.

The first one is to start with the positive electrode material of the battery, and select some high-temperature-resistant and flame-retardant materials, so that the performance of the positive electrode material of the battery is not so active, thereby reducing the risk of fire.

It's just that the idea is good, and it can indeed reduce the activity of the positive electrode material, which often means that the energy density of the battery is greatly reduced.

Reduced to a certain level, the battery has no competitive advantage in the market at all.

If the drop is too small, the effect will not be great, if the drop is too much, the battery will be useless.

Moreover, carbon-based batteries with high energy density are really useless if there are fewer idle ones.

This is tantamount to cutting a knife on one's own thigh, it is going to bleed profusely.

Second, start with the electrolyte of the battery.

The electrolyte is very important to the performance of the battery.

Generally speaking, the positive and negative electrode materials of a battery cannot be changed after being determined.What can be changed and has the greatest influence is the electrolyte.

For many special batteries, such as high temperature resistance, high cold resistance, or particularly high charge and discharge rate, the mainstream design concept is to use different electrolytes.

From this point, we can see the impact of electrolyte on battery performance.

There was a time when there was an upsurge in researching electrolytes in the lithium battery industry in order to solve the problem of battery fire.

The most typical is the solid electrolyte.

Traditional electrolytes are liquid, and solid electrolytes, as the name suggests, are solid or gel.Compared with liquid electrolytes, solid electrolytes have natural advantages in fire prevention and flame retardancy.

It's just that the technical difficulty of solid electrolyte is too high. After a period of research, the heat of the market has come down, and the industry continues to use liquid electrolyte.

This point can make a big breakthrough. Jiang Ming wrote down the solid electrolyte.

The third is to start with the battery separator.

The thermal runaway of the battery, in the final analysis, is the internal short circuit of the battery cell.This is the case whether it is due to foreign matter, or metal precipitation due to abuse.

If the thermal runaway can be terminated from the process of short circuit in the cell, then the occurrence of thermal runaway can be fundamentally suppressed.

The main feature of the internal short circuit is that the positive and negative electrodes of the battery are in contact together, forming an internal cycle.

Therefore, terminating this internal circulation in the early stage is a way to solve the thermal runaway of the battery.

To solve the internal short circuit, the role of the diaphragm is quite important.

In the lithium battery industry, there was an idea to develop a more intelligent diaphragm that can automatically switch ion channels after sensing changes in temperature.

When the temperature is normal, the ion channel is fully opened, and there is no limit to the charging and discharging of the battery.

When the internal temperature of the battery is abnormal, the channel of ions is automatically closed, and the internal short circuit of the battery will also be terminated synchronously.

This kind of design is very imaginative, but the idea is good, but it is extremely difficult to realize it.

Among them, how to automatically control the channel of ions according to the temperature is the most important thing. After so many years of research, there is still no progress.

The fourth point is to start with the explosion-proof valve of the battery.

At present, the battery cells of vehicles all have explosion-proof valves.

The function of the explosion-proof valve is to act as a pressure relief channel when the internal pressure of the battery is abnormal and the pressure is too high.

Prevent the internal pressure of the battery from being too high and eventually explode.

The current battery explosion-proof valve is relatively simple, that is, to passively relieve the internal pressure according to the pressure difference between the inside and the outside.

Although it has a certain effect, how to put it, the actual effect may not be as great as imagined.

The above-mentioned methods are sorted out by everyone, and they are relatively reliable solutions.

Of course, this reliability is also relative.

It is only theoretically analyzed, and it is possible to realize it.However, the technical difficulties in it have not been overcome.

Aiming at these four technical means, everyone launched a heated discussion.

Although Jiang Ming presided over the meeting, in fact, Jiang Ming said relatively little. Most of the time, Jiang Ming was listening to the opinions of different people, and then analyzing the possibilities.

Jiang Ming summed up the ideas discussed by everyone, and generally had an idea in his heart.

At present, the fourth type, the explosion-proof valve, is the easiest to realize.

But although it is easy to achieve, it is also difficult to make greater progress.

Fortunately, someone suggested that in a research institute, there is a similar explosion-proof valve technology.Higher sensitivity and faster response can be used as an alternative.

As for the other types, the public says that the public is right and the woman says that the woman is right, and when everyone argues, there is no final conclusion.

Seeing that after nearly two days of discussion, there was still no good plan, and Jiang Ming had an idea in his mind.

The first one is the selection of positive and negative electrode materials.

This is the inherent design of carbon-based batteries, which is to achieve this extreme energy density.

If it is really for safety to reduce the energy density of the battery cell, there is no need to develop this new battery.

It is born for high density, and it is a bit unrealistic to reduce the figure.

As for the electrolyte, Jiang Ming felt that it was an idea. As for how to realize it, Jiang Ming already had a preliminary plan.

Others may not understand the technology of solid electrolyte, but Jiang Ming still knows a little.

But according to Jiang Ming's understanding, the solid electrolyte is not as magical as everyone imagined.

Moreover, the solid electrolyte was not developed to prevent the battery from catching fire.Of course, this kind of battery also has certain fire-resistant properties, but if it is really used as a flame-retardant material, it is a bit unwise.

(End of this chapter)