Chapter 249 More like a cheat than a cheat
Xu Qingzhou stayed in the laboratory for an hour. After the samples had entered the long charge and discharge test, he left the laboratory and went next door to concentrate on his own tasks.
Although there is a lot of data, Gong Yunfei has already preprocessed it before, so there is no need for him to screen the data as before.
After thinking for a moment, Xu Qingzhou decided to finish the electrochemical model first.
Of course, since the working principle of batteries involves electrochemical reactions, this topic also involves chemical materials, but the core purpose of the experiment is through physical means.
Such as electrical testing, thermal analysis, material structure characterization, etc., to study and improve the thermal stability and energy density of lithium-ion batteries.
He has a little dabbling in chemistry, so he can’t be said to be good at it, but he’s pretty good at making models and the like.
First, the solid-phase diffusion equation describes the diffusion process of lithium ions inside the electrode active material particles.
Xu Qingzhou took out the manuscript paper and wrote down the formulas to be used.
【\frac{\partialc_s}{\partic_s}{\partialr}\right)】
There are also liquid phase diffusion equations, solid phase potential equations and liquid phase potential equations as well as electrochemical reaction equations.
These are the key formulas in the electrochemical model.
In addition to this, it also involves the specific formula of activation polarization overpotential, such as using the Butler-Volmer equation to describe the electrochemical reaction rate on the electrode surface.
Of course the entire model is not just a matter of splicing a few equations together. If it were that simple, Professor Zhao wouldn't come to him specifically.
These equations are equivalent to the main frame of the building, as well as roofing work, interior wall painting, etc. Only when these are fully completed can there be a complete and usable building.
Moreover, in actual experiments, due to the influence of factors such as the complexity and non-uniformity of the battery's internal structure, these formulas need to be appropriately corrected and adjusted in most cases.
Just talking about the diffusion coefficient, the theoretical diffusion coefficient is likely to not fully reflect the actual diffusion behavior of the material. This requires fitting the experimental data to obtain the effective diffusion coefficient under different conditions and inputting it. into the model.
“Huh~”
Xu Qingzhou slowly exhaled and clicked on the data graph.
Maximum capacity 4000mAh/g100μA16 cycles. Charge and discharge efficiency 92%.
At 4:30 in the afternoon, the printer next door buzzed, and data diagrams and battery internal structure diagrams were spit out from the printer.
Wang Wei and Hong Yayu walked out of the laboratory and checked the material structure characterization diagram of the battery in front of the printer.
Xu Qingzhou also put down the calculations at hand and followed Wang Wei and others to see the situation of sample No. 138.
Wang Wei pointed to the dendritic scattered shadows in the picture and introduced to Xu Qingzhou: "This is lithium dendrites, one of the key factors affecting battery life and safety. At present, there is no effective way to completely prevent lithium dendrites. Method of dendrite growth.”
“However, compared with the original sample, the lithium dendrites have dropped by 70%.”
Xu Qingzhou nodded and said: "But the current growth situation still cannot meet the quality requirements of the battery."
"Well, yes, this is one of the reasons why we asked you for help, just like you last time As I said, the data does not lie, so we hope to find experimental loopholes in the data and how to control the variables to inhibit the growth of lithium dendrites. "
Lithium dendrites. This thing is quite challenging. .
Xu Qingzhou really wanted to give it a try, but gave up after thinking about it carefully. His main task now is to solve the Polignac conjecture and improve his mathematics level.
Or occasionally participate in experiments in other physics fields like this, get in touch with new things, and lay the foundation for being a pentagonal warrior.
Wang Wei put the drawings in order, "Let's go, finish the last set of experiments, and then we can get off work."
"Yes."
Hong Yayu nodded expressionlessly.
At 5 o'clock in the afternoon, Xu Qingzhou did not stay in the laboratory. He packed up his things and went to meet Song Yao. Wang Wei and the others wanted to work together to finish the experiment today and enjoy the Dragon Boat Festival holiday tomorrow.
The most comfortable thing is the first night before the holiday. Xu Qingzhou and Song Yao also planned to have a sense of ceremony and not eat in the cafeteria. They made an appointment to buy some food together, get some bacon, four dishes and one soup.
Cooking and eating, the two of them sat on the sofa and watched TV. In the evening, they called Lao Xu and Lao Song to ask if the rice dumplings they bought had arrived.
Friday passed like this.
Saturday.
Xu Qingzhou originally wanted to sleep in, but he couldn't fall asleep after 9 o'clock, so he just woke up with a haha. As soon as he opened the curtains, the bright sunlight fell on him through the glass.
The weather is very good, and it’s already June in the blink of an eye. When July comes, it will be called summer.
Song school beauty seemed to have just woken up, and the few strands of hair on her forehead were still wet. Seeing that she seemed to be planning to go out, Xu Qingzhou asked: "Are you going to buy breakfast?"
" "Yeah."
"Wait for me, let's go out to eat."
Xu Qingzhou rushed to the bathroom to wash up, wash his face and brush his teeth.
At 9:30, the sun hangs brightly in the sky, without the fierceness of noon. It falls on the ground through the leaves on both sides of the road, casting a mottled halo.
Xu Qingzhou and Song Yao held hands and walked out slowly and leisurely. They were different from usually going to the library or class, and had a more leisurely atmosphere.
"This kind of life is called life." Xu Qingzhou sighed again and squeezed Song Yao's soft little hands. Even though he could now touch her legs, he still liked her hands very much.
He kind of agreed with that sentence. He used to think that he was a face control, then he thought he was a leg control, and then he suspected that he was a hand control. It was only today that he realized that he was not a control at all, he was just purely lustful. That’s all.
Song Yao glanced at the person next to her. This guy didn't even walk honestly, so she pinched him back.
Xu Qingzhou countered unconvincedly, and Song Yao pinched it back again. The two of them just pinched me once, and I pinched you once.
This childish slapstick attracted a look of contempt from the bachelor next to him.
Haha, stinky couple.
After returning from breakfast, the two of them cleaned up first.
According to Xu Qingzhou's past habits, it was usually cleaning day whenever friends came over. Now that there is a school beauty from Song Dynasty, he cleans much more diligently, but he still picks up a lot of garbage.
After the cleaning was done, the two of them, wanting to spend the whole day, lay down on the sofa to rest.
Song Yao was leaning on the sofa with her legs on Xu Qingzhou's lap, chatting with her little sister Ding Jiahui, talking about the route to Yandong Garden and planning what to eat in the evening.
Xu Qingzhou squeezed his legs and checked the messages on his mobile phone at the same time, only to realize that a major event had happened in the field of mathematics during this period, or that a competitor for him had emerged, a contender for the Fields Medal.
Young mathematician Jonatan Birmingham.
Oh, only 23 years old.
Some time ago, it was announced that the exponential ergodicity of the solution under the 1-Wasserstein distance was proved, and a criterion for the exponential ergodicity of the Mahalanobis semigroup on Banach space under the 1-Wasserstein distance was proposed.
In addition, he also founded the regularity structure theory, which is a generalization of the rough orbit theory of stochastic differential equations and involves model theory, Hopf algebra, partial differential equations, stochastic analysis and generalized functions. Modern mathematical theories such as nonlinear operations.
At present, it has won many international awards such as the Whitehead Award of the London Mathematical Society, the Philip Leverhulme Award, and the Froehlich Award.
Now he is a popular candidate for the 2018 Fields Medal.
After reading this person's resume, Xu Qingzhou smacked his tongue. He should say it or not. This person seemed to be more cheating than him.
A battle between cheaters.
(End of this chapter)