Application of Electrochemical Simulation Technology in Lithium Battery -Lithium - Ion Battery Equipment
With the launch of the national fuel vehicle sales ban schedule, the position of new energy vehicles has become increasingly stable. As the core power source of electric vehicles, lithium-ion batteries are increasingly sought after by the market. The fabrication of lithium ion batteries involves the selection and matching of materials such as positive pole, electrolyte, negative pole and diaphragm, and the selection of design parameters of electrode plates; The working process of battery involves chemical reaction, mass transfer, conductivity, heat generation and other processes. It can be seen that lithium ion battery is a very complex system.
It is an effective means to explore lithium ion battery by means of experiment. Especially with the continuous progress of characterization means, we can get more and more information about the impact of design parameters, working conditions, etc. on battery performance. It is undeniable that in the process of lithium ion battery development, there are too many design parameters and heavy experimental tasks; The influence of each parameter on the battery performance is not clear, and the experimental design has a certain blindness. Sometimes, it even takes time, effort, and money, but it is hard to please. The opportunity to improve this situation is to apply battery simulation technology to batteries.
Lithium ion battery simulation technology can adopt equivalent circuit model, semi empirical model, electrochemical model, etc. The simulation technology based on electrochemical model can well solve the problems mentioned above. As a supplement to the experiment, electrochemical simulation can simulate various schemes before the experiment to eliminate the turnip; It can also simulate the charging and discharging process of the battery under different working conditions, which is helpful for researchers to understand the internal process of the battery; At the same time, the experimental results can also point out the shortcomings of simulation and promote the continuous development of simulation models. It can be said that the simulation makes the experiment more powerful and the experiment makes the simulation more beautiful.(Lithium - Ion Battery Equipment)
Application of 01 Simulation Technology in Battery Design
In the process of battery design, in addition to the inherent property parameters of positive and negative electrode materials, electrolyte and diaphragm, many design parameters need to be considered, such as particle size (r) of positive and negative electrodes, thickness (L) of electrode sheets, and porosity of electrode sheets（ ε） Etc. Marc Doyle and others used simulation technology to simulate the magnification of Sony's graphite battery, and the obtained battery magnification performance was very close to the test results. The following figure shows the comparison between the test results and simulation results of charge discharge curves at different magnification.
In the process of battery development, you can first use the model to find out the relationship between the design parameters and battery performance, determine the main influencing factors, and then conduct experiments on this factor, which can greatly reduce the amount of experiments.
Simulation of side reaction and lithium evolution in 02 battery
In LiMn2O4 battery, when studying the self discharge caused by the co embedded side reaction (irreversible) of electrolyte solvent (PC) and lithium ion, the low speed CV curve is used as the model correction standard, and the transfer coefficient of the side reaction is used as the variable parameter. The side reaction transfer coefficients are different for the batteries with different active substance loads. It is difficult to control and monitor the side reaction in the battery, and it is sometimes an effective means to obtain the physical and chemical parameters related to the side reaction by using model and parameter identification.
03 Battery internal resistance
Internal resistance is a very important performance index of battery, which has an important impact on fast charging, heat generation and aging of battery. If the ohmic internal resistance, reaction internal resistance and diffusion internal resistance of the positive and negative electrodes and electrolyte in the battery can be clearly analyzed through the model, it will be very beneficial to improve the battery performance.
04 Battery life prediction
There are many reasons for lithium ion battery capacity degradation, such as material structure collapse, lithium consumption due to side reaction, lithium consumption due to SEI and its increase in internal resistance, lithium precipitation, etc. For the convenience of calculation, only one or two attenuation reasons are considered in the general model.
It is an effective means to explore lithium ion battery by means of experiment. Especially with the continuous progress of characterization means, we can get more and more information about the impact of design parameters, working conditions, etc. on battery performance. It is undeniable that in the process of lithium ion battery development, there are too many design parameters and heavy experimental tasks; The influence of each parameter on the battery performance is not clear, and the experimental design has a certain blindness. Sometimes, it even takes time, effort, and money, but it is hard to please. The opportunity to improve this situation is to apply battery simulation technology to batteries.
Lithium ion battery simulation technology can adopt equivalent circuit model, semi empirical model, electrochemical model, etc. The simulation technology based on electrochemical model can well solve the problems mentioned above. As a supplement to the experiment, electrochemical simulation can simulate various schemes before the experiment to eliminate the turnip; It can also simulate the charging and discharging process of the battery under different working conditions, which is helpful for researchers to understand the internal process of the battery; At the same time, the experimental results can also point out the shortcomings of simulation and promote the continuous development of simulation models. It can be said that the simulation makes the experiment more powerful and the experiment makes the simulation more beautiful.(Lithium - Ion Battery Equipment)
Application of 01 Simulation Technology in Battery Design
In the process of battery design, in addition to the inherent property parameters of positive and negative electrode materials, electrolyte and diaphragm, many design parameters need to be considered, such as particle size (r) of positive and negative electrodes, thickness (L) of electrode sheets, and porosity of electrode sheets（ ε） Etc. Marc Doyle and others used simulation technology to simulate the magnification of Sony's graphite battery, and the obtained battery magnification performance was very close to the test results. The following figure shows the comparison between the test results and simulation results of charge discharge curves at different magnification.
In the process of battery development, you can first use the model to find out the relationship between the design parameters and battery performance, determine the main influencing factors, and then conduct experiments on this factor, which can greatly reduce the amount of experiments.
Simulation of side reaction and lithium evolution in 02 battery
In LiMn2O4 battery, when studying the self discharge caused by the co embedded side reaction (irreversible) of electrolyte solvent (PC) and lithium ion, the low speed CV curve is used as the model correction standard, and the transfer coefficient of the side reaction is used as the variable parameter. The side reaction transfer coefficients are different for the batteries with different active substance loads. It is difficult to control and monitor the side reaction in the battery, and it is sometimes an effective means to obtain the physical and chemical parameters related to the side reaction by using model and parameter identification.
03 Battery internal resistance
Internal resistance is a very important performance index of battery, which has an important impact on fast charging, heat generation and aging of battery. If the ohmic internal resistance, reaction internal resistance and diffusion internal resistance of the positive and negative electrodes and electrolyte in the battery can be clearly analyzed through the model, it will be very beneficial to improve the battery performance.
04 Battery life prediction
There are many reasons for lithium ion battery capacity degradation, such as material structure collapse, lithium consumption due to side reaction, lithium consumption due to SEI and its increase in internal resistance, lithium precipitation, etc. For the convenience of calculation, only one or two attenuation reasons are considered in the general model.
