What do you have a small battery behind how you become the wind direction of the electric car industry?

　　Author ：Iflowpower – Portable Power Station Supplier

Battery is the "heart" of electric cars. Since the development of electric vehicles, all kinds of technical routes will constant, and they will argue. Among them, the most widely used lithium-ion battery, there is a phenomenon that there are various technical routes of three yuan, lithium iron phosphate, lithium manganate.

At the same time, the lithium-ion battery is also divided into square, soft bag, and cylindrical form. And this is more inseparable, the more you can still explore, representing an urgent expectation of electric cars: electric cars should have a strong "heart". Requirements for battery packs related to electric vehicles - battery, we are required to be safe, energy density, long life, short charging time, and excellent performance, etc.

This requirement, seems harsh, but none is not an electric vehicle to achieve industrialized hard indicators. So how is the electric car battery? How can it be a good performance? There is no doubt that the lithium-ion battery is used as its most basic unit, and its advantages and disadvantages are crucial. But take the safety of our most attention, is it safe, the battery pack is safe? We can see that in 2002, lithium iron phosphate (LFP) was first industrialized by the US Valance, and then attracted extensive attention from our market.

Since 2004, my country has set off a boom that invests in lithium iron phosphate materials and lithium iron phosphate powered lithium-ion batteries. The lithium phosphate is relatively stable, and the safety is high. Subsequently, it became an important route of my country's positive material, the dispute temporary paragraph.

However, as Tesla uses the positive material of lithium nickel-cobalt aluminate in the power lithium-ion battery, the debate is again. Lithium iron phosphate has a lower energy density, which has made it in a disadvantage. (Three-yuan materials) According to the development, since 2014, the overall domestic lithium-ion battery positive material industry has emerged, and the downstream battery factory is basically developing the cells of the three-yuan material, also guided The upstream material company began to increase the development and production of ternary materials.

And a series of changes, simply explaining that the lithium battery industry is slowly explored, slowly moves. For example, a battery pack is safe, and the electric battery safety is far less than enough, it must rise to a system level. In other words, the safety of the battery pack is the entire battery system, not just a single element.

What's more, a safe, reliable and excellent battery pack, which involves the coupling of multi-domain knowledge, which is more perfect, reliable system to achieve. It is like a plane that the plane is considered to be the safest vehicle. It is not only "safe" engine, "security" structure, which can guarantee, which also uses human factors, software security, risk management and quantitative risks.

Various advanced technologies such as assessment to prevent accidents, it can be said that the system guarantees safe. Below we will draw a core component battery module from the battery system, talk about a variety of different module structures. The battery module battery module can be understood as a combination of lithium-ion batter string and add a monomer battery monitoring and management device.

The structural design of the battery module often determines the performance and safety of a battery pack. Its structure must support, fix, and protect the battery. At the same time, how to meet overcurrent requirements, current uniformity, how to meet the temperature of the electrical core temperature, and if there is a serious abnormal abnormality, it can be powered off, prevent chain reaction, etc.

, will be the standard of evaluation of battery modules. With the development of electric vehicles, as well as people's pursuit of performance, heat management has become a crucial link for battery module design. Natural cooling can no longer meet our needs.

Air cooling is less efficient due to the low efficiency, and the performance of the performance is not from the heart. Therefore, the battery module of high-performance demand, its thermal management has been turned to liquid cooling or phase change material. Let's introduce the module design of various different structural cells.

Square Battery Module Square Core can be said to be my country's automobile power lithium-ion battery, the most used battery. The material of the outer casing has aluminum, steel, and plastic. Its electrical core thickness is the thicker in three structures, thereby causing the temperature difference between the inside and the outer surface.

Its module structure is also a natural cooling and air-cooled structure. Let's take a look at BMW I3 battery module design. We can see that the battery module of the i3 has a high performance module required, and a high-performance electric vehicle is to build together by the details of each place.

Of course, its heat dissipation, average temperature, and reliability, etc., there is also a verification of the market. (▲ BMW I3 Square Battery Module) Its battery is the BEV2 specification of the VDA standard, the combination of the module is 1P12S, and the thick aluminum plate is fixed around.

The aluminum plate is combined with welding and attached to the side of the module. Its module structure is very strong, but it is also non-removable. The power connection between the module and the module uses the wire form and has specially developed a connector for easy connection.

At the same time, whether it is more reliable, both the strong wire or the acquisition line, the ultrasonic welding is connected to the connecting piece of ultrasonic welding. The connecting piece is connected to the battery by using laser welding. NTC is a collection of temperature on the connecting piece.

After completing, the upper surface is also covered with a blister disk. It can be seen that the entire module is completed, the structure is very firm and reliable, and all connections are also neat and orderly. Of course, there is also the most critical point, the thermal management of the battery.

The design of the i3 module is thermally conducting a bottom plane. The bottom surface of the module is in contact with the cooling pipe attached to the bottom of the battery case, and the cooling conduit is a refrigerant. This design cooling pipe can be tiled in the bottom of the box, and its structure is simple and reliable, suitable for mass production.

(▲ BMW I3 Square Battery Module) Soft Bad Battery Module Soft Package Coelectric Battery Bag, which is also a structural type that is hot in the near future, which is more useful in foreign electric vehicles. The physical structure of the soft bag decision has determined that it is not easy to explode. It is generally only high enough pressure to be affected, and it is possible to blow, and the internal pressure of the soft bag battery will be bleeded from the edge of the aluminum film.

liquid. At the same time, the soft bag battery is also the best in several batteries. At present, the most market selling is still the LEAF of Nissan, and its module structure is full-sealed, and the heat dissipation is not considered.

And the capacity of Leaf's frequent feedback in the market is too fast, and it is not related to this thermal management. Obviously, as people's pursuit of high-performance electric vehicles, forcing soft bag batteries must have active thermal management structures. Let's take a look at the liquid-cooled soft package module on a WorldCongress booth.

The module is stacked by the electrical core, and there is a liquid cooler arranged in the battery cell, which guarantees that each of the cells have a large-faced liquid-cooled plate, and fully exerts the soft bag electrical core cold. The advantages. (▲ liquid-cooled soft bag battery module) Of course, the soft bag should be mature, it must consider the fixation, sealing, insulation, etc.

of liquid cold plates. At the same time, reliable electrical connections, and "fuse" structure connectors, this is the direction of high performance soft bag modules. We can see that the soft bag battery is combined with the perfect module structure, its advantages will be highlighted.

Cylindrical battery module cylindrical cells can be described as the most widely used structure in various electronic products. Today, there is a certain share in the electric vehicle industry. The most typical is the 18650 battery, and the process has been deposited for many years, and under the conditions of large-scale automation, it is the most mature, stable and consistent battery cell.

The cylindrical cell has the current highest energy density, and the cells of its ternary materials can do 210 ~ 250Wh / kg. The current cylindrical battery pack is mostly naturally cooled or air-cooled, and its effect is not satisfactory. Let's take a look, push the cylindrical cell to Tesla battery module on the tip of the wind.

I believe that many people have seen Tesla's modules: forming a Tesla car to have more than 7,000 18650 cells, one module has more than 400 batches, while for high performance goals Integrate multiple functions on the module, you can see the workload and difficulty. Among them, even the use of some cross-industry technology, making people look bright, for the case. So than the "fuse" design connected to the battery.

It can be said that people in the battery industry, but few people can think of it, this may be the authorities. The application of this technology greatly improves the safety performance of the battery. At the same time, there is also the application of liquid-cooled pipeline, which greatly solves the problem of heat dissipation and warmth of 18650, which is a great help for the performance and life of the battery.

Not only that, the use of battery modules in spatial size is more likely to be fine. Here, I have to admire Tesla to make things extreme attitudes, that is, such a module, becoming a high-performance Tesla battery pack. Core components.

(▲ Tesla Cylindrical Battery Module) (▲ Tesla Cylindrical Battery Module) Electric Heart Through some simple listed, we are not difficult to see, no matter what structured, the battery is actually uncomfortable. Application example. And the lithium-ion battery, if as a revolutionary product, there is still a lot of shortcomings and limitations.

However, we are in the development of materials, it is better to consider how to do battery modules and do battery systems. And this is the only way we create a strong "electric heart". .