Energy density is deeply rooted in people's hearts.
To explain the power battery module of electric vehicle clearly, we must first understand what the common parameters of power battery mean. The first is the battery energy density, which many people like when studying battery parameters.
Strange to say, the parameter of battery energy density is actually a domestic feature, and some non-domestic car companies did not publish relevant information in the early days. For example, Tesla only announced the energy density of Panasonic batteries, but rarely mentioned the energy density of the whole battery pack. With the increase of domestic new energy sales, many car companies entering China have begun to do as the Romans do. In addition to battery capacity, battery energy density is also a parameter often emphasized on the configuration table.
There are two formulas for calculating battery energy density, namely, battery weight energy density and battery volume energy density. The greater the energy density of the battery, the more electric energy is stored per unit volume or weight.
Battery weight energy density = total energy/battery weight, basic unit? Wh/kg？ (WHr/kg)。
Battery volume energy density = total energy/battery volume, the basic unit is? Wh/L？ (Watt hour/liter).
There is one thing to note here. The energy density of the battery will sometimes see different data, one is the energy density of the single battery, and the other is the energy density of the battery pack. For users of pure electric vehicles, although the energy density of batteries can reflect the strength of power battery suppliers, the energy density of battery packs is more valuable data. As we all know, the battery cell is the smallest cell of the battery system. x？ Cells form a module, n? Each module forms a battery pack. Therefore, the high energy density of a single battery cell does not mean that the energy density of a battery pack is high.
This leads to a question we are going to talk about today-module.
Modules that are ignored by everyone.
After introducing the energy density of the battery, I believe everyone has a question. Why don't people abroad pay much attention to energy density? On the one hand, domestic subsidies are closely related to this parameter, and the other reason is the design of vehicle engineering structure. For a fuel car with many years of development history and mass production at another level, is it Toyota's? TNGA, or Volkswagen? MQB, more and more automobile companies take modularity of infrastructure as their research and development focus. But for pure electric vehicles, after all, the whole transformation process is only in an initial stage. Regarding modularity, there are actually few standards. In order to realize modularization, the modules of battery pack must be considered in advance.
Size aspect
Regarding the module size of the power battery, did you mention the battery introduced by the German Automobile Industry Association? VDA？ Standard size. What are the common early pure electric vehicles in China? 355? Module (what is the length of the module? 355mm)，in？ PHEV？ Up there? 390? There are more modules. This kind? 355? This module was first introduced by German Automobile Industry Association? VDA？ After the standard battery size, apply the standard module in public places. What is the size? 355 *151*108mm.
390? package
Audi? A6？ PHEV？ Going? LG？ Is the module provided typical? 390? Module, size? 387 *151*108.5mm. 。
Volkswagen pure electric platform? MEB？ With 590? package
With the development of electric vehicle industry, power battery suppliers have started? 590? Module conversion. At present, many models with relatively high battery life, such as GAC New Energy? Eternal tower? LX？ Everything has changed? 590? Module, this? 590? This figure actually means that the length of the module is 590 mm. then what 590? Is the module also a pure electric platform for the public? MEB？ The developed standard module has all the conditions to become a universal module from the beginning.
Contemporary Ampere Technology Co., Ltd? 590? package
It can be said that the size change of the whole module is nothing more than one reason, in order to make better use of space or to improve the volume energy density. After all, the battery weight and energy density have encountered some bottlenecks, and better module layout is naturally the next step for car companies.
Height of battery cell
Compared with the size of the module, the height of the battery cell has also changed a lot. Like the early BMW? i3？ The battery pack * * * consists of 8 modules, each module has? 12? Battery series, * * * meter? 96? The batteries are connected in series. The specific cell size is 173mm* 125mm*45mm, and the battery size is1660mm * 964mm *174mm. As you can see, where is the height of the battery pack? 174 mm.
Bmw i3? Electricity?
Tesla battery pack? What is the height of the back? 120mm
For the current pure electric vehicle, it needs a larger battery pack, so it is very important to consider the height of the battery. Will Tucki be listed soon? P7？ For example, the battery size of this car provided by Contemporary Ampere Technology Co., Ltd. is: 44mm*220mm*85mm, which is made by Contemporary Ampere Technology Co., Ltd.? 590? Large module scheme (590mm*225mm* 109mm), including? Did you reach the height after that? 1 10mm, better than Tesla? 120mm is lower than that of early BMW? i3？ The height of the battery pack is even worse to 64 mm, so on the chassis of the car, Tucki? P7？ You can also install an 8 1kWh battery pack.
Tucki? P7？ what's up 8 1kWh battery pack
Eternal tower? LX？ What else to use? 590? Large module
Guangzhou Automobile New Energy? Eternal tower? LX？ Is it also provided by Contemporary Ampere Technology Co., Ltd.? NCM8 1 1？ Batteries, too? 590? Big module, 8? Each battery cell forms a module. As a person. SUV，Aion？ LX？ The height of the battery cell is not so strict, but the layout position of the battery pack is too high, which will increase the floor inside the car and have a negative impact on the ride comfort; If the layout position is too low, the battery will protrude from the ground, which will affect the passability of the vehicle, so the new low-height battery of Contemporary Ampere Technology Co., Ltd. is adopted.
Don't think that layout is not a big deal. The recall before Weilai was actually related to the module. According to the announcement, the improper direction of the voltage sampling harness in the module may be squeezed by the upper cover plate of the module, which may cause the skin insulation material of the squeezed voltage sampling harness to wear, and in extreme cases, it may cause the insulation layer of the harness to burn, thus causing the battery pack to get out of control and catch fire, posing a safety hazard. In addition to the design of the battery, safety should also be considered. Packing? At the same time, the layout and internal wiring of the module need to be carefully considered.
Module-free patent
In addition to layout, power battery suppliers also have their own explorations in some technical directions. BYD and Contemporary Ampere Technology Co., Ltd. both found technology patents? CTP (cell? Where to? Pack)? This plan. In fact, this new technical scheme is to improve the space utilization rate and turn the whole battery pack into a large module.
Take BYD as an example. BYD's blade battery is self-developed, and its length is greater than? 0.6? Battery cells are also evolving to large capacity, but the shape of the cells is flatter and narrower (the long side can be customized, and the maximum stable length of the cells can be achieved? 2 100mm), the batteries are stacked like "blades" and inserted in the battery pack, which is why it is called "blade battery".
In the traditional three-stage assembly mode, the batteries are assembled into modules, and then the modules are installed in the battery pack, and the space utilization rate of the battery pack is only 40%. The adoption of blade batteries? CTP？ This technology integrates battery cells directly into the battery pack, thus eliminating the intermediate module link. Since the module is directly integrated into the battery pack, the space utilization rate of the battery pack exceeds? 60%, compared with ordinary battery space utilization? 50%。
The electric platform is the end point.
The development process of these modules mentioned above is actually some exploration in the early stage of electric vehicle development. For large-scale electrification, the electrification platform is the end point. At present, many car companies have their own electrification platform: Volkswagen? MEB？ Platform, Audi? J 1？ High performance electric platform, MEB? Platform and? PPE？ Platform, the second generation GEP platform of GAC New Energy, Geely? PMA platform and so on. These pure electric platforms are nothing more than to solve the problem that "oil to electricity" can't solve.
common people
Popular? MEB？ Platform and? MQB、MLB？ Different platforms, Volkswagen? MEB？ The platform uses batteries with different capacities according to different models, and is fully compatible with the design of cylindrical, square and flexible batteries without affecting the system integration. And this platform will shoulder the public? 50 pure electric vehicles and? 30? Production and listing of plug-in hybrid electric vehicles. 590? What does this module consist of? MEB？ The platform has risen.
Audi
Except? MLB？ evo？ Fuel car platform to build Audi? Electronic creation? In addition, the future of Audi's electric vehicles is mainly based on? J 1？ High performance electric platform, MEB? Platform and? PPE？ Platform.
What is this based on? J 1？ Porsche with high performance electric platform? Tekan? It has been delivered. And Audi itself is based on? J 1？ Pure electric vehicles with high-performance electric platforms still need to wait for some time.
Be widely used
General motors? 2020? The third generation electric platform was released in 2006, which will cover all models, including pickup trucks and performance cars. And introduced a lithium-ion battery pack developed for future pure electric vehicles, and named it? Last minute.
Ultimate? Is the battery pack compatible? 50-200kWh？ Match the capacity of different models and support the maximum? 350kW？ The charging ability. In order to reduce battery cost, GM has cooperated with? LG？ Chemistry? Cooperation, the official said that the new battery uses low cobalt chemicals, and the battery cost will be reduced to every? Kwh? About what? 100? Dollars. GM's third-generation pure electric vehicle platform will first appear in Cadillac and will be shared with other GM brands.
Guangzhou automobile new energy
The first generation of GAC new energy? GEP？ Is the platform representative familiar to us? GE3. The second generation? GEP？ What is the first model of the platform? Eternal tower? s，Aion？ LX？ This is the second model of the platform. In order to arrange a larger battery in the car to get a better cruising range, it has become a conventional engineering idea to replace oil with electricity at the expense of passenger compartment or trunk space. Domestic GAC New Energy Second Generation Pure Electric Exclusive Platform? GEP？ Is to solve this problem. The second generation? GEP？ Can platform derivative models be covered? A0-C？ Class models, cruising range from? 300-700 kilometers.
lucky
Geely also revealed? PMA？ Platform plan, PMA? What is the coverage of platform LinkedIn pure electric vehicles? A+/B？ Class crossover, city car, C+? Class family intersection and? A+/B？ Class SUV.
For these car companies, modularity can not be ignored is the module size of batteries. With more and more cooperation between traditional automobile giants, power battery manufacturers will gradually formulate new standards for battery size according to the design basis of most platforms. Whether there is a module or not, the size of the battery pack will still be a key consideration for car companies.
Edit the summary? /
The enjoyment of new energy vehicles in powertrain will go further than that of fuel vehicles. For the later pure electric vehicles, modularization will be the inevitable development direction. After the layout of electric platforms becomes more and more abundant, the selection of battery modules is likely to be more unified. For many new car companies that don't have enough self-research strength, cooperation with big manufacturers will weaken the investment of the three power companies. Perhaps in the future, the electric vehicle industry will be similar to the mobile phone industry. OPPO？ For consumers, after the new forces have hardware based on mature electric platforms, they can concentrate on differentiated design.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.