Plug-in hybrid with 800V in the car, Great Wall Motors fired the first shot.
Its subsidiary Honeycomb Energy recently announced its latest progress:
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In one sentence, Great Wall has used 800V, ultra-fast charging, and ultra-long battery life in hybrid models.
A global first.
How did you do it? Why has no one been able to achieve it before?
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And the key question is, is it necessary to use 800V for hybrid vehicles?
Great Wall Hybrid, the first to use 800V in the car
Key information: Suitable for 800V, 3C charging rate, hybrid only.
One of the most important new developments in Honeycomb Energy is the ternary lithium dagger battery code-named L300.
The two models have a single cell capacity of 160AH and 100AH respectively, and are respectively adapted to 400V and 800V platforms.
Why is the capacity of a single 400V battery cell larger?
In fact, it is easy to understand. A single battery cell is connected in series in the battery pack, and the positive and negative voltages of the entire pack are the accumulation of “1+1+1…”. The working voltage requirement of 800V is higher than that of 400V. If the total capacity of the battery pack is the same, more cells need to be connected in series, and the individual capacity will be smaller.
Let’s do some simple science here. The so-called 800V platform refers to the vehicle battery, motor, and electronic control module. The working voltage is between 550-930V. This is a recognized technical standard and industry rule. Therefore, the 800V platform is not necessarily the exact 800V.
And the 800V platform is not just about batteries. The user experience involves motors, electronic controls, energy management, and charging infrastructure.
Therefore, Honeycomb’s new progress is to complete the 800V adaptation at the battery level, and to cooperate with Great Wall Motors’ battery pack technology to put such a high-voltage platform on hybrid models.
What kind of experience can it bring?
According to the technical parameters disclosed by Honeycomb, the L300 (800V) ternary lithium battery pack can achieve a battery pack of 55-65 kWh.
Calculated based on the average wheelbase of a hybrid C-class vehicle being 2800-3000mm and the vehicle weight being 2.0-2.3 tons, such a battery pack can support a pure electric range of 350km+.
It's big enough, especially in a C-segment car.
In addition, the L300 supports 3C rate fast charging, which means that the peak charging power is three times the battery pack capacity, which is about 160-200kW.
This means that it only takes about 20 minutes for hybrid models using the L300 to charge from low battery to about 80%.
The usage experience is the same as that of a pure electric vehicle, and a pure electric vehicle with a range of 300km will generally not use 800V due to cost considerations.
How did you do it
In the past, different car companies and battery companies have been trying to make large battery extended range/hybrid vehicles.
But the maximum range is only about 300km, and the price paid is to make the compact wheelbase as wide as a D-class executive car.
Pay attention to the width, because the battery pack is too big, and the exhaust pipe, fuel tank, etc. must be arranged vertically on the hybrid vehicle chassis, so more cells can only be inserted horizontally.
Therefore, under the original technical system, the pure electric cruising range and the upper limit of design ideas of hybrid vehicles are severely stuck.
There are two innovation points of Honeycomb Energy, one is the battery cell form – short knife, and the other is the production process – flying stack.
The short knife is easy to understand. It has the same blade battery, but is shorter:
Why use such technology? The explanation given by Honeycomb is that the first 400 mm and 600 mm long dagger battery cells have higher efficiency in the finished product.
Because at this size, it is 25% thinner than ordinary square batteries, the battery pack volume utilization is higher, and the battery's interface cycling and other performances will be better.
If traditional VDA (battery cell standard proposed by Germany) cells are used for fast charging, achieving a 5C rate requires cooling on three sides, and a 6C rate requires large-area cooling in the middle of the cell. However, using short knife batteries only requires upper and lower water-cooling plates. The design has better continuity and the temperature difference is much smaller than the maximum temperature difference of VDA batteries.
This is the key to a larger total capacity and longer battery life after the honeycomb hybrid battery is packaged.
In terms of safety, the CTC (battery integrated in the chassis) architecture usually has the battery cell poles facing upward. Once heat diffusion and flame spray occur, the car cab will be very dangerous. However, after the bottom plate of the dagger battery is eliminated, the water-cooled plate can be used as the lower floor of the car. At the same time, the flames after thermal runaway will spray towards the bottom or both sides, which will cause less harm to the cab.
How to achieve fast charging on the short knife? For the positive electrode material of the battery, Honeycomb Energy uses advanced doping coating technology to reduce the ion transmission path by 40% and the resistance by 10%; the negative electrode material uses new surface technology and the matching technology of primary particles and secondary particles. , and additives with better liquid absorption to achieve better negative electrode power performance.
As for the electrolyte, Honeycomb Energy has also redesigned it. Through material innovation and the direct welding process inherent in the short knife, which is similar to the full-lug battery, the current carrying area is larger, and fast charging can ultimately be achieved.
The flying stacking process is the core technology of Honeycomb. This process was gradually introduced into power battery manufacturing in 2018.
Honeycomb flying stacking technology is not the traditional Z-shaped lamination process in which separators and positive and negative electrode sheets are stacked together. Instead, the negative electrode sheet is first covered with two layers of separators, then thermally compounded by a heating roller and the separator is edge-sealed, then cut into pieces, and finally stacked with the positive electrode sheets in sequence.
The key here is slicing. The traditional winding process only requires two cuts at the front and back, but the disc process requires many cuts, and the risk of burrs is much higher than that of the winding process. (Burrs are a major factor in battery accidents and can pierce the separator and cause a short circuit).
Honeycomb’s flying stacking production line is covered with CCD monitoring equipment to ensure that the surface of each pole piece is smooth and wrinkle-free, and that the pole pieces are stacked neatly and without misalignment.
Honeycomb revealed that the overall yield rate has reached 93%. In fact, this yield level is close to the standard of square wound wire in the CATL era.
A breakthrough in the flying stacking process solves the production capacity problem. Global dagger battery cells solve the problem of fast charging and capacity. The choice of technical route is actually also a commercial consideration.
Honeycomb also revealed to Smart Car Reference that it will focus on hybrid-specific batteries in the future and adapt them according to the requirements of car companies.
After all, the two giants Ningde and BYD win based on quantity, and it is difficult to make too many customized changes for hybrid vehicles.
Hybrid 800V, is it necessary?
Finally, let’s talk about this key issue.
For comparison, current plug-in hybrid vehicles, whether extended-range or hybrid, have a pure electric range of 270 or 280 kilometers. With discounts for low temperatures in winter, the pure electric range is about 100km.
Therefore, the greatest significance of Honeycomb Energy’s new products is to fully realize “large battery hybrid”, with a pure electric range of 350km+, and can run about 200km even with discounts in winter.
This allows users to do their daily grocery shopping and commuting without the need for extra fuel. Charging can also be controlled to 1-2 times a week.
Therefore, the greatest significance of Great Wall Motors and Honeycomb Energy's work is to make the power consumption experience of hybrid vehicles consistent with that of pure electric vehicles, with ultra-long battery life and ultra-fast charging.
At the same time, hybrids also have energy-supplementing advantages that pure electric vehicles cannot match.
With the blessing of large batteries, hybrids will further surpass pure electric vehicles in terms of experience and economy, and will further explode.
Therefore, the step Great Wall has taken in new energy is not called “make-up lessons”, but “super-comprehensive”, aiming at the rise of hybrid vehicles in about 25 years.
Moreover, it is a truly usable, practical and easy-to-use hybrid car, not a cheap hybrid car with a marginal green card policy and a range of only 50km.
This is also Great Wall's strategy to avoid the 100,000-level entry-level market that BYD is best at and directly occupy the mid-to-high-end hybrid market.