Easy car originalOn December 14th, ZEEKR's first self-developed battery, the Golden Brick Battery, was officially released, and for many consumers, it may be the same as BYD blade battery, SAIC Rubik's Cube battery, and Ningde Kirin battery, but with a different name. But for the industry, when this battery is "self-developed", "the world's fastest mass production of lithium iron phosphate batteries", "the world's first volume utilization" and other words, it is destined to be extraordinary.
What does it mean to be self-developed?
In the era of fuel vehicles, the core three major technologies are emphasized, and the car companies that have not mastered the core technology are now basically eliminated. In the new energy era, full-stack self-development is still the goal pursued by major car companies, from hardware such as power and battery, to software such as cockpit intelligence and electronic control.
However, in the field of power batteries, only a few car companies such as BYD can really achieve complete self-development, and most of the others also have their own power battery research and development technology, but most of them stop at the battery system level. In other words, the battery cells still have to be purchased from the top manufacturers such as CATL, and the car companies only complete the packaging of the battery pack. So don't look at so many car companies have released their own battery products, and the names are more domineering than the other, but few of them really have core technologies.
Of course, BYD's blade battery is fully self-developed, and GAC has also released a full-stack self-developed Inpai battery, and now there is an additional ZEEKR gold brick battery, which is also self-developed and self-made from the cell level.
In addition to better solving the problem of system matching, self-developed batteries also have the biggest advantage of reducing costs and increasing efficiency. For example, ZEEKR said that the self-developed gold brick battery has increased the production efficiency by 40%, and the cost per kilowatt-hour has been reduced by 148%。In most new energy vehicle companies are still in the stage of selling cars at a loss, the cost of batteries, which accounts for the majority of the cost of the whole vehicle, has declined, which can undoubtedly alleviate the financial pressure of car companies, and can also enhance competitiveness on the product side and give consumers more profits.
"Lithium blade iron battery" under the 800V high-voltage platform
The gold brick battery of ZEEKR, like BYD's blade battery, uses blade lithium iron phosphate cells, but the difference is that it uses short knife cells, which are only about 500mm visually, and the starting point is an 800V platformMost of BYD's long knife cells are long-knife cells, with a cell length of 600-2500mm, mainly 400V.
It can also be seen from the arrangement of the battery pack that BYD's long knife battery cell can cover the width of the battery pack, while the ZEEKR gold brick battery is spliced together by two short knife cells.
The outer packaging of the battery cell is not the traditional blue insulating film, but the golden high-voltage resistant insulating film, which not only makes the gold brick battery more worthy of its name, but also can withstand 4000V DC high voltage, and the high-voltage resistance is increased by 27%, and it is not easy to short circuit.
As for which is better, short knife cell or long knife cell, I think each has its own advantages, long knife can reduce the number of cell cells, which is more conducive to thermal management. However, the short knife is more suitable for fast charging above 800V and 4C, because the shape of the long knife cell is too long, the path that the charging current needs to go through is very long, the charging time is long, and the charging and discharging current is more likely to thermally run if it is too largeMoreover, the deformation of the chassis is also more likely to lead to a short circuit in a large area of the battery, resulting in spontaneous combustion. Short-knife cells can reduce these risks.
It solves the charging pain point of lithium iron phosphate battery
Although there is no more detailed information on the battery cells at the moment, I think that judging from the published information alone, the BRICS battery is enough to make people stunning, especially its fast charging ability.
You should know that the slow charging speed is a major pain point of lithium iron phosphate batteries, ordinary lithium iron phosphate batteries, even in the 30%-80% fast charging range, the charging time still needs more than 30 minutes, which is about 2C charging rate. However, the ZEEKR gold brick battery adopts an 800V architecture, the electrode adopts a laminated multi-tab structure + double riveting pole diversion design, and a lithium-ion full acceleration technology, with a maximum charging rate of 45C, the maximum charging power can reach 500kW, and in the 10% 80% fast charging range, the battery life can be increased by more than 500 km in 15 minutes.
What is this concept, at present, 2C, 3C fast charging is the mainstream level, 6C is the ceiling, and only a few ternary lithium cell batteries can do it, and the gold brick battery of ZEEKR lithium iron phosphate has achieved 45C, even compared with many ternary lithium batteries, the charging speed is far ahead, and lithium iron phosphate batteries have officially entered the era of overcharging.
In terms of discharge rate, the pulse discharge rate of the gold brick battery can reach up to 16C in 3 seconds, which will not limit the power output of the motor at all. Equipped with a gold brick battery, ZEEKR 007 can easily achieve 000 acceleration performance in 3 seconds.
As for the fact that lithium iron phosphate batteries are afraid of cold, the official does not clearly state the discharge capacity at low temperatures, but only that it can ensure ultra-fast charging performance in harsh environments: even in -10 low temperature environments, gold brick batteries can still achieve excellent charging speed, and their charging speed is at least a quarter higher than that of similar products.
Although the volume utilization rate is high, there is still room for improvement in energy density
After all, lithium iron phosphate batteries are far inferior to ternary lithium cells in terms of energy density, so it is necessary to improve the space utilization rate as much as possible. BYD officials have said that the space utilization rate in the traditional modular battery pack is only 40%, and the space utilization rate of the blade battery can reach 60%-80%, and the space utilization rate has increased by more than 50%.
But now the gold brick battery has directly dried this data to 837%, which is the first in the world. Referring to the volume utilization rate of various power batteries currently mass-produced, 4680 batteries are 63%, ordinary lithium iron phosphate batteries are 66%, and ternary lithium batteries are 72%.
In order to achieve this goal, BRICS Battery has also made a number of technical transformations: for example, the use of integrated liquid-cooled trays at the bottom of BRICS batteries to replace the traditional water pipe structure to reduce the squeeze of structural parts on the cell space;The second is to use the "compact sandwich structure" of the cell, upper cover and bottom plate to release the longitudinal space of the cell warehouseThe third is to use aviation-grade ultra-thin thermal barrier materials between battery cells to fully improve the volume utilization rate.
In addition, compared with the traditional design, the total length of the sampling line of the BRICS battery has also been shortened by 157 meters, the number of core components has been reduced by 35%, and the energy density of the battery quality has also been increased by more than 10%.
Of course, here I think one of the data that everyone is most concerned about is how much the energy density of the battery system reaches under such a high volume utilization rate. Although it was not officially announced, according to the engineer, the energy density of the battery cell exceeded 250wh kg, and I also saw the nameplate parameters of the finished battery pack in the factory (not allowed to take pictures):Capacity 756kw·h, mass 589kg, rated voltage 610V。Calculate the energy density of the whole package128wh kg
Referring to the energy density of the first-generation blade battery currently used by BYD, the energy density of the second-generation blade battery can reach 180Wh kg, and the energy density of the Kirin battery (ternary lithium cell) of CATL is 255Wh kg. It can be seen that although the volume utilization rate of ZEEKR gold brick battery is very high, there is still a lot of room for improvement in the energy density of the system.
Safety plus three extreme tests
For batteries, there is no safest, only safer, and no matter how much the standard is raised, it cannot be overstated. In order to pursue a higher standard of battery safety, ZEEKR first upgraded the 6 major safety measures of the polar core battery pack of the BRICS battery pack to 8 items to achieve real-time protection of the global safety of the battery pack.
Moreover, in order to verify the safety of the battery, ZEEKR has also designed three extreme safety test subjects.
The first is the "overpressure acupuncture test", which is to upgrade the traditional "acupuncture test", and the gold brick battery cells in a fully charged state will first be 1 with the national standard5 times the extrusion force to apply pressure, so that the extrusion deformation of the cell reaches more than 30%;After standing for 1 hour, a 5mm steel needle is used to puncture and penetrate from the point with the greatest degree of bending, so that the battery cell is directly short-circuited. The whole process can realize that the battery cell is not **, non-**.
The second is the "external fire test", in the battery pack fire laboratory of the National Motor Vehicle Product Quality Inspection and Testing Center, the experimenters test the gold brick battery through the direct fire of the oil pan, the flame temperature of the contact battery pack is above 700, and the continuous fire time is as long as 240 seconds, which exceeds the test time of the national standard of 130 seconds, and the battery pack is still not **, non-**.
The third is the "6 extreme working condition tests", that is, the same gold brick battery will be continuously subjected to 6 extreme tests such as immersion, fire, freezing, dragging, rolling, and high falling, but even so, the gold brick battery is still not, no.
You should know that lithium iron phosphate batteries have safety advantages compared with ternary lithium batteries, and lithium iron phosphate blades are more conducive to safety protection than ordinary lithium iron phosphate in structure. On this basis, ZEEKR has added a higher standard of testing, which I think is enough to dispel everyone's concerns about the safety of BRICS batteries.
Editor's Summary:As far as the existing technology system is concerned, the ZEEKR brick battery has obviously been in the leading ranks, fast charging and cost reduction are its biggest advantages, although there are still some shortcomings, but through 1 to 2 years of market application and technology iteration, it should be able to improve quickly. In any case, it is a good start for ZEEKR, after all, it has mastered a core technology. It is said that this battery will first be installed on the model of the ZEEKR 007 standard endurance version, and the new car is about to start test driving, and the actual endurance performance of the battery will soon have results.