You may feel a little boring, such as the prediction of charging curve, the superposition and comparison of the packaging sizes of 2 170 battery and 4680 battery, the configuration of series and parallel batteries, and the way Tesla connects batteries ... but these contents will reveal to us what kind of use effect a new car will bring us.
4680 battery is safer? Tesla's 8-year battery cooling defect will be improved.
Some foreign media commented that Tesla's new 4680 battery pack will adopt a simpler and easier-to-assemble flat cooling scheme and abandon the original cooling scheme. Although Tesla officials did not particularly emphasize the use of flat-panel cooling scheme, there is no way to effectively cool these large-diameter batteries through the side. The most effective cooling method is through both ends of the battery. The new earless battery provides a good heat conduction path between the battery cover and the inside of the battery.
Regarding Tesla's battery heat dissipation defects, in this year's 6? Month? 30? On Sunday, an email inside Tesla was exposed and made public. As early as? 20 12? Annual mass production? Models? s？ At that time, Tesla already knew that there was a problem with the heat dissipation of the battery, which might even lead to a fire. This problem has not been solved so far, and it has been eight years!
Tesla has commissioned three companies to test and investigate the battery cooling configuration, and the results all show? Models? s？ There is a problem with the end connection connector of the cooling system. Tesla's battery cooling system is realized by adding an external coolant pipe to the battery. However, the end joint of the pipe is made of aluminum, which is low in strength and easy to wear, causing coolant leakage, causing short circuit and fire in the automobile battery, or leaving flammable residues inside the battery.
The copper anode plate itself can play a good role in heat dissipation, making the internal temperature distribution of the battery more uniform. It seems that eight years of security risks will be solved!
In addition, Musk said: The battery cells are attached to the plates at the bottom and top of the battery pack. While increasing the shear strength of the battery pack, the top and bottom plates will also serve as cooling plates. At model? 3. The battery is stuck on the radiator.
How fast does the 4680 battery charge? 10%-80% takes 15 minutes, 10%-50% takes 7 minutes.
Maximum charging speed: 275 kW
Below is the model? 3 and model? y？ Comparative analysis of 2 170 battery pack and 4680 battery pack.
In the temperature environment of 29.4 degrees Celsius (85 degrees Fahrenheit), the charging time from 10% to 80% is reduced from 25 minutes to 15 minutes. If you only need to charge 50% of the electricity at most, it can be completed in 7 minutes, almost as fast as the refueling time of a gasoline car.
It is estimated that the maximum charging rate will be increased from 250kW for 2 170 battery to 275kW for 4680 battery. The charging rate of 275 kW remains unchanged, and gradually decreases from 10% to 50%. When the battery reaches the temperature limit, it begins to change gradually, according to the model? X, if the temperature is 45 degrees Celsius (1 13 degrees Fahrenheit), the transition point is related to the ambient temperature density. At higher ambient temperature, the performance of air conditioning system will decline.
The following is a comparison chart of the charging curve and time relationship between 2 170 battery and 4680 battery.
The following is a comparison chart of the relationship between the charging curve and the state of charge (SOC) of 2 170 battery and 4680 battery.
We can see that the size of the battery pack has been significantly reduced, and Tesla can pack the battery more tightly after the cooling mode is changed. This is an advantage because it reduces the polar moment of inertia and improves the handling of the vehicle, because the mass will be more concentrated in the center of the vehicle.
What is the next 96S9P? 76? Kwh? Section view of 4680 battery pack.
In the cross section of the 4680 battery pack, the flat cooling of the top and bottom and the electrical connection of the battery are shown. Will Tesla cancel? The concept of finger current collector is changed from wire welding to simple flat current collector, which is directly welded to the battery connected to the anode or cathode of the electrodeless ear.
In order to connect the anode of one battery with the cathode of another battery, what type? Based on S-type inversion technology, the battery cells of each parallel battery pack are turned over.
The following are 76 kWh 4680 battery packs and 2 170 models? 3 Cross-sectional coverage of battery pack.
As mentioned earlier, it is expected that there will be a top radiator and a bottom radiator, and the battery and radiator will be glued together. The heat dissipation plate will also increase the strength of the battery pack, and the heat transfer ratio between the cathode (aluminum) end and the anode (copper) end of the battery is 30%/70%.
The thermoelectric model includes all the specific contents of the battery pack, including battery size, ampere-hour rating, thermal conductivity and so on. One of the key factors is the resistance of the battery, because it determines the calorific value of the battery. The new 4680 electrodeless battery is at 10%? The initial internal resistance at SOC is 3? Milliohm, 80% of the time? SOC gradually drops to 2? Milliohm. 2 170 battery resistance 23/20/20? Milliohm. We can see that the resistance of the battery is reduced by 10 times. In contrast, the technology marked by Tesla in the patent application can be reduced by 5-20 times.
In addition, the cooling capacity is also worthy of attention. Existing model? The refrigerating capacity is 2-3 tons, depending on the ambient temperature. ? Tesla may increase the size of stacked refrigeration and air conditioning compressors to provide better packaging cooling effect.
The thermal mass of the battery pack will also play a role. In the first part of charging at the maximum charging rate, the heat generated by the battery exceeds the range that the refrigeration system can keep up with, so the battery pack begins to heat up. Thermal mass will delay the occurrence of battery overheating because it stores heat. When the battery reached the temperature limit of 45 degrees Celsius (1 13 degrees Fahrenheit), it began to gradually reduce the charging rate.
The picture above shows the relationship between air conditioning performance and ambient temperature. At higher ambient temperature, the performance of air conditioner will decline, which is why the initial gradual change point of maximum charging power will appear at lower SOC at higher ambient temperature.
Zhang Ning's new doctor (Secretary-General of Austria-China Science and Technology Exchange Association, working in a famous technical research institute in Europe)
The innovation of Tesla battery mainly comes from the innovation of peripheral non-core structure, such as increasing the size of battery core and relatively reducing the proportion of shell. The real improvement of energy density must and can only be achieved through material innovation. The innovation of production technology can reduce the cost, but it has little effect on the energy density. The innovation of anode and cathode materials will bring a leap in the performance of lithium battery electrochemical system, but it needs long-term scientific research and accumulation.
Engineer Jin Min (battery expert, working for a world-renowned automotive technology company, member of Austrian Chinese Automotive Engineers Association).
Tesla's battery cathode design is quite novel. The internal resistance of the traditional cylindrical battery is higher than that of the shell and the soft bag, which is about 20mΩ. This new design can be reduced to below 10, so the energy consumed in the internal resistance of the battery is much less.
The design of the battery pack is to directly remove the module CTP (Cell to pack, Cell? Where to? Pack), which is similar to that promoted by several domestic companies recently. ? However, looking at this cross section, there is some concern about the anti-extrusion and collision ability of the battery pack. The internal reinforced upper and lower supporting structures are gone.
There are no specific investigation reasons and data, and there are no enterprises and institutions in China in the above list. Let's just say more efforts are needed.
Wang Jun (senior engineer of well-known European automotive technology company, Austrian Association of Chinese Automotive Industry Engineers? ACSAE？ President? )
From 2000 to 20 18, the number of battery technology patents registered ranked in the top 25 in the world.
Despite the development of batteries, Tesla is considered as the pioneer of electric vehicles. ? But the company did not even appear in the ranking of most patents in the field of battery technology.
I have some ideas to share about battery recycling. During 20 19 and 1- 12, the total output of power batteries in China was 85.4GWh, up by 2 1.0% year-on-year. The recycling of batteries can definitely reduce the cost of new batteries. As far as the development of domestic automobile industry is concerned, Weilai Automobile has started the business model of renting batteries for electric vehicles, which makes the management of battery production, maintenance and recycling more centralized and provides better conditions for battery recycling. I am optimistic that the cost of automobile power batteries will be rapidly and continuously reduced.
Dr. Wang Yongli (ceramic battery material expert, working in the European branch of the world-famous electronic raw materials and components company, member of the Austrian Association of Chinese Automotive Engineers)
The recovery of battery raw materials requires very professional knowledge, skills and equipment, including a perfect industrial system. Simply put, separating and regenerating these raw materials for battery production from old batteries may not save money than extracting new raw materials from ores under current conditions, so this is not only an opportunity but also a challenge.
Of course, from the perspective of sustainable development and environmental protection, the recycling of waste battery materials is of great significance.
Tesla has begun to recycle electrode materials, expecting to greatly reduce the cost from localization and raw material selection (ranking third). Especially cobalt material, as a relatively expensive transition metal, China's cobalt resource reserves only account for 1% of the global total, and cobalt resources are very short. The amount of cobalt metal in self-produced ore is only about 1.500 tons per year, and the dependence on imports exceeds 90%. Tesla's thinking on research and development and manufacturing of electrode materials is worth learning and thinking in our battery industry.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.