Tesla just announced the mass production and installation of 4680 batteries into vehicles. CATL launched its third-generation CTP technology - Kirin battery.
According to CATL, the volume utilization rate of Kirin batteries exceeds 72%, and the energy density can reach 255Wh/kg, which can enable the vehicle to exceed 1,000 kilometers of driving range.
In addition, this Kirin battery also supports 5 minutes of fast hot start and 10 minutes of fast charging through the world's first large-area cooling technology for battery cells.
It is reported that the battery is planned to be mass-produced and launched in 2023.
After the release of Kirin Battery, Li Auto and Nezha Auto successively forwarded the news about the release of Kirin Battery, and the official account of CATL also responded to the news from the two companies. Li Auto and Nezha also became the first batch. Confirm new energy companies that will be equipped with Kirin batteries.
Regarding this battery, according to the official description of CATL: under the same electrochemical system and battery pack size, the material is a ternary high-nickel version of Kirin battery, which is 13% higher than the Tesla 4680 of the same volume. The energy density and performance far exceed Tesla 4680. Is the
Kirin battery really stronger than the Tesla 4680 battery? Let’s take a closer look at the differences and gaps between the two.
External upgrade VS internal upgrade
In fact, Kirin battery and 4680 battery are two different technical concepts. Kirin battery is an iteration of battery system technology, while Tesla 4680 is an iteration of battery cell technology.
1. Kirin Battery
Let’s first look at the Kirin battery. In essence, it does not change the internal structure and materials of the battery core, but the change is the structure of the battery system. Its main innovations are as follows:
1, using an inverted cell design
Different from the standing CATL VDA, 590 modules and the lying SAIC Rubik's Cube battery, the CTP3.0 True Kirin battery is an inverted battery, that is, a battery. The core is inverted, and this design can make the space utilization of the battery pack higher.
Judging from the arrangement, when the cells of the Kirin battery are inverted, the out-of-control exhaust and bottom ball hitting space can be shared, leaving 6% more space for the cells, resulting in higher space utilization. The current space utilization rate of Kirin batteries is as high as 72%, which is 17% higher than the first-generation CTP.
2, integrated into a multi-functional elastic interlayer
CATL's pioneering cross beams, water-cooling panels and thermal insulation pads were originally designed independently, integrated into a multi-functional elastic interlayer, making the support, cooling, heat insulation and buffer functions four-in-one , effectively improving space utilization.
Moreover, a micron bridge connection device is built in the multi-functional elastic interlayer, which can flexibly expand and contract in conjunction with the cell breathing, improving the reliability of the cell throughout its life cycle.
In addition, the battery core and multi-functional elastic interlayer form an integrated energy unit, which builds a stable force-bearing structure perpendicular to the driving direction, improving the battery structural strength and impact resistance.
3, reconstructed water cooling system
In terms of cooling, Kirin Battery has carried out a new layout design of the cooling system.
First of all, Ningde Times started from the essence of heat exchange , reconstructed the water cooling system, and placed it between the large surfaces of the battery core, which greatly improved the heat exchange efficiency of the battery core, and its heat exchange area can be expanded four times.
Secondly, Ningde Times has shortened the temperature control time of the battery core to half of the original, more efficiently maintaining the safe and suitable working temperature of the battery core, thereby adapting to larger current and higher voltage fast charging. It is reported that the current Kirin battery can support 5 minutes of fast hot start and 10 minutes of fast charging to 80%.
In extreme situations, the battery core can cool down rapidly, effectively blocking abnormal heat conduction between battery cells, effectively avoiding irreversible damage caused by abnormal battery operating temperatures, and effectively improving the life and safety of the battery core.
To sum it up in one sentence, Kirin battery has achieved comprehensive improvements in battery life, fast charging, safety, lifespan, efficiency, and low-temperature performance.
2. Tesla 4680 battery
Friends who know a little bit about Tesla must know that Tesla’s power battery naming method has always been simple and crude.4680 battery, as the name suggests, is a cylindrical battery with a single cell diameter of 46mm and a height of 80mm.
Comparing the past "1865" and today's "2170", from the naming point of view, the 4680 seems to have just a larger battery, from the previous "5th battery " to "No.2 battery". Of course,
is not just that simple. In addition to becoming larger, the 4680 battery cell also has many innovations and improvements in structure.
1. Adopt "poleless ear" design
As the volume of the battery core increases, the battery impedance also increases simultaneously. Tesla's solution to this problem is to adopt an innovative "poleless ear" design.
The tabs are metal conductors drawn from the positive and negative current collectors. It is through the tabs that current can be connected to the outside of the battery. However, too slender tabs are not conducive to current conduction. If the current is too large, heat will occur, energy loss will increase, and safety performance will be affected.
Tesla’s 4680 battery removed the original tabs and chose to leave the end of the current collector blank and uncoated with positive/negative electrode materials. To put it simply, it is not that there are no tabs, but that the entire end surface has become a tab. This design greatly reduces the impedance of the battery and solves the heating problem of cylindrical batteries.
2, using dry battery electrode process
Tesla 4680 battery uses dry battery electrode process, no solvent is used, but a small amount (about 5-8%) of finely powdered PTFE binder is mixed with positive/negative electrode powder, and passed through The extruder forms a thin strip of electrode material, which is then laminated to a metal foil current collector to form the finished electrode. This process will increase the energy density of batteries and reduce production energy consumption by 10 times.
3, the anode is made of silicon material
In terms of anode material, Tesla will start with silicon material. Silicon can store ten times more electrical energy than graphite , but it has been difficult to replace graphite because its volume changes up to 400% during charging and discharging and is easily broken.
Tesla plans to fundamentally change the ductility of the silicon surface to make it less likely to break. This technology can increase battery life by 20%. Tesla named the new material developed "Tesla Silicon" at a cost of US$1.2/KWh, which is only one-tenth of the existing structured silicon process.
4. Improving the cathode production process
In terms of cathode materials, Tesla has reduced the investment and construction costs of the battery cathode production line by 66% and 76% of the production costs by improving the cathode production process and reducing the use of water and the generation of waste water. At the same time, Tesla has launched a battery recycling service. In the future, new batteries will be produced from recycled old batteries.
Combining these improvements, Tesla will increase battery life by 54%, reduce cost per kilowatt hour by 56%, and reduce investment and production costs by 69%. In addition to increasing energy density, production costs will be greatly reduced.
Finally, let me summarize the advantages of the 4680 battery in one sentence: it can achieve both performance and cost.
In summary, although Kirin batteries and 4680 batteries have iteratively upgraded battery technology, they are different in their technical routes.
Kirin battery improves the performance of the battery by upgrading the battery pack structure through "external upgrades" without changing the battery core material, such as changing the discharge position of the battery core, integrating it into a multi-functional elastic interlayer, etc.;
The Tesla 4680 battery makes itself stronger through the "intrinsic upgrade" of the battery core, such as expanding the battery cell volume, changing the anode material, etc.
Of course, whether it is an external upgrade or an internal upgrade, the final result is still to obtain better battery performance.
So, what is the performance between Kirin batteries and Tesla 4680 batteries?
Kirin battery performance far exceeds Tesla 4680?
Judging from the data provided by CATL, the cylindrical 4680 battery is still slightly insufficient compared with Kirin batteries in terms of energy density, fast charging performance, integration and thermal conductivity. Let’s take a look at them one by one.
1, energy density
From the data, the energy density of the 4680 unit is about 300Wh/kg, and the energy density of the battery pack is 217Wh/kg.In comparison, the Kirin battery pack has a capacity density of 255Wh/kg. In other words, under the same cell chemical system and the same battery pack size, the power of the Kirin battery pack is 13% higher than that of the 4680 battery.
2, volume utilization rate
In addition, the volume utilization rate of Kirin Battery's battery pack has exceeded 72%, which is 9% higher than the 63% of the 4680 battery, setting a new industry record and becoming the most integrated battery in the world.
Kirin battery has higher space utilization. In addition to the structural optimization of integrating into a multi-functional elastic sandwich and using battery cells inverted, Tesla's battery has an inherent bug due to its innate cylindrical shape, so it can only be used for 60 %about.
This is easy to understand. Due to the physical structure of the cylinder, there are physical gaps between the cells, but for square cells, this problem basically does not exist. In other words, the same battery pack is more compact inside with square cells and can be packed in. Go for more power. And prismatic batteries can make the cells as large as possible, thereby maximizing space savings and improving energy density.
3, thermal conductivity
Although large cylindrical batteries are not as good as square batteries in terms of space utilization, the advantage is that large cylindrical batteries have more space for heat dissipation. In addition, Tesla designed a layer of water-cooled plates for them, so the thermal conductivity is better than ordinary batteries. Square battery. In comparison, prismatic batteries have relatively large single cells and are in surface-to-surface contact when placed on the chassis. The heat dissipation is inherently not as good as that of cylindrical batteries.
However, according to Kirin Battery, after reconstructing the water-cooling structure, its thermal conductivity has increased by 50%, and judging from the comparison results, it seems to be even better than the Tesla 4680 battery. Of course, this may mean that if companies want prismatic batteries to have better heat dissipation than cylindrical ones, they will need more cost and effort.
4, fast charging performance
According to the information and data reviewed, the Tesla 4680 battery pack can be charged from 10% to 80% in just 15 minutes, which is 10 minutes faster than the current Tesla 2170 battery pack. For comparison, the current Kirin battery can support a 5-minute fast hot start and a 10-minute fast charge to 80%. It can be seen that in terms of charging efficiency, Kirin batteries are higher than Tesla 4680 batteries.
5, safety
First of all, the cylindrical battery cells are small, resulting in a large number of cells in the battery pack, which have high requirements for thermal management and BMS. The safety is worse. In theory, the risk of spontaneous combustion is greater.
In comparison, Kirin Battery uses prismatic batteries with large cell capacity and a small number of cells. The BMS system has a relatively simple structure and relatively good stability.
Secondly, compared to 4680 which improves energy density by changing the cell material, Kirin battery only upgrades its structure, which is theoretically safer and more stable.
6 and 4680 battery packs have low efficiency and low production capacity.
4680 battery production is not easy. Otherwise, it would not have been delayed for almost two years. Among them, the main difficulty lies in the low yield rate caused by the extremely difficult laser welding of the tabs.
It is reported that the yield rate of 4680 manufactured by Tesla was only 20% at first, and it will increase to 80% by October 2021. Now, its yield rate has reached an average of 92%, with the highest reaching 97% and the lowest being 79%, which has basically reached the level of starting mass production.
Secondly, the 4680 battery production capacity is limited. Data shows that Tesla will sell 936,000 vehicles in 2021. In 2022, Tesla stated that it would not launch new models and choose to fully expand production capacity. This means that exceeding the one million sales mark in 2022 is just the beginning, and it is not impossible to achieve annual sales of 1.5 million vehicles.
With such a huge sales volume, it is obviously impossible for Tesla to achieve full product coverage with 4680 batteries if it wants to be evenly exposed to rain and dew.
According to Tesla, its production capacity in January was 1 million units, and 1 million units only installed 1,000 Teslas. In other words, each Model Y requires approximately 1,000 4680 batteries, which is the same as Tesla. Compared with the annual delivery volume of 1 million, it is obviously a drop in the bucket. Well, in order to meet Tesla's goal of delivering more than 1 million vehicles in 2022, it is essential to purchase from friends to make up for the production capacity.
So, this is why Tesla not only purchases a large number of prismatic batteries from CATL, but also accounts for an increasing proportion.
Judging from the above comparison, the comprehensive advantages of Kirin battery may be higher. In terms of energy density, fast charging performance, space efficiency, and thermal conductivity, Kirin batteries are better than 4680 batteries. Moreover, in terms of safety, stability, production capacity, group rate, etc., 4680 batteries are not as good as Kirin batteries.
We can see that since BYD launched blade battery , battery manufacturers and car companies including CATL, Great Wall Motors , GAC Aian and other battery manufacturers have upgraded battery performance by improving the battery pack structure. It not only ensures the safety and stability of the battery cells, but also improves the battery performance and increases the cost. It can be seen that the external upgrade of batteries is also a good technical route for battery development.
So here comes the question. As one of Tesla’s main battery suppliers, CATL will use Kirin batteries in the future? Everyone is welcome to leave a comment below!
