How to reduce battery cost, improve energy density and increase cruising range?
CTP technology may be the best choice at present!
The full name of CTP technology is Cell? Where to? Pack, also known as module-free technology, has two different technical routes. The first is to completely cancel the module scheme, represented by BYD blade battery; The second is to integrate small modules into large modules, represented by CTP technology of contemporary Amperex Technology Co., Ltd. In addition, BYD blade batteries focus on lithium iron phosphate batteries, while Contemporary Ampere Technology Co., Ltd. mainly focuses on high nickel ternary lithium batteries.
■? What are the characteristics of BYD CTP technology?
BYD blade battery is based on this kind of front shell battery, and the battery core is made "long" and "thin", and its shape is similar to that of a blade. According to public information, BYD has five different battery specifications, and the specific data are shown in the following table. In fact, the height of this battery has not changed compared with the current square shell battery, and the thickness is slightly thicker than the soft bag battery. The main change is the length, from 435mm to 2500 mm How BYD did it here is still unclear according to the current data.
If this kind of battery cell wants to form a battery pack, it depends on CTP technology. On the one hand, this technology improves the utilization rate of the space in the battery pack and increases the charging capacity; On the other hand, the weight of the bag is reduced and the energy density of the whole bag is improved.
According to BYD's patent application, it can be seen that the existing battery structure has many components such as side plates, end plates, fasteners, cross beams and longitudinal beams of each module, and the space utilization rate in the package is about 40%. BYD battery pack using CTP technology, except for battery management system, distribution box and other components, the space utilization rate is about 62%. Affected by different battery cell layout, the space utilization rate in the package is 55%, 60%, 62% and 65% respectively, and even 80% if necessary. Even for the same car, after using the battery pack with CTP technology, the battery capacity will increase by about 20%-30%, and the cruising range will also increase by 20%-30%.
■? What is the difference between CTP technology of Contemporary Amp Technology Co., Ltd.?
At the Frankfurt Motor Show last year, Contemporary Ampere Technology Co., Ltd. released some information about its CTP technology. This battery pack consists of at least two large modules (as shown below), and each module is connected with the battery tray through fasteners. Finally, the battery pack is fixed on different models by mounting beams.
According to the patent of Contemporary Amperex Technology Co., Ltd., a large module is divided into small spaces by several plastic cooling plates, and the battery with square shell can be inserted into these small spaces like a computer hard disk. A heat-conducting silica gel gasket is attached to the side of each battery cell, and a heat dissipation channel is left on the heat dissipation plate in the width direction of the battery cell, which can be directly connected with an external cooling pipeline. According to relevant data, this can reduce about 40% of the parts, which come from the connecting wiring harness, side plates and bottom plates between modules. In addition, under the condition of constant battery volume, the volume utilization rate of battery pack using CTP technology is also improved by 15%-20%.
■? What are the advantages of CTP technology?
1, lightweight. CTP technology can minimize the number of side plates, bottom plates, connecting harnesses, fasteners, unnecessary beams, longitudinal beams and other components inside the battery pack, which is very helpful for the lightweight of the battery.
2. The energy density of the battery is improved. There are two levels. The first is the weight energy density, which is also common to us. Taking CTP technology of Contemporary Ampere Technology Co., Ltd. as an example, the specific energy density can reach 200Wh/kg. The second dimension is volume specific energy density. Take BYD's CTP technology as an example, the volume specific energy density can be increased by 50% compared with the past, and the volume specific energy densities of batteries with different specifications are 439Wh/L, 448Wh/L and 449? Wh/L、450？ Wh/L .
In contrast, the weight specific energy density of BYD lithium iron phosphate battery pack with CTP technology has reached 180Wh/kg, which is equivalent to the battery pack with NCM8 1 1 battery at present.
3. Low cost. In fact, an important driving force of CTP technology is to reduce the cost of power batteries. Take BYD as an example, the cost of new products can be reduced by 20%-30%. This includes the cost of the battery pack itself, as well as the factors that simplify the production and assembly process and lead to the decline of the defective rate. Although Contemporary Ampere Technology Co., Ltd. did not disclose the cost advantage, the positive impact of 50% increase in production efficiency can not be ignored.
■? At present, some problems about CTP technology?
1, battery collision safety. Because of the existence of modules, the traditional three-level battery pack has an extra layer of protection for collision safety. The battery pack using CTP technology will directly bear the impact of collision except the side beam of the battery pack.
According to the existing data, taking Contemporary Ampere Technology Co., Ltd. as an example, the frame of Pack is directly extruded from aluminum profiles to increase strength; The plastic shell inside each large module is injection molded, and the heat dissipation plate is embedded in the box mold during injection molding to realize integral molding.
2. Battery thermal management. Because new technology has changed the structure of battery pack, it is bound to put forward new design requirements and strategies for battery thermal management system and even BMS system, which is a software consideration.
From the hardware level, BYD has designed a brand-new exhaust hole and exhaust passage for this battery pack. The vent holes face the explosion-proof valves at both ends of the battery unit. When the flame, smoke or gas is discharged from the explosion-proof valve, it will enter the exhaust passage through the exhaust hole and be discharged out of the battery pack. The existing battery pack has no similar exhaust channel design, and flame, smoke or gas can easily gather in the module, causing secondary damage to the battery cell.
Design of BYD blade battery exhaust duct (103 is explosion-proof valve, 22 1 is exhaust hole and 222 is exhaust duct).
A similar design is also seen in the patent application of contemporary Amperex Technology Co., Limited, and in view of the fact that ternary lithium batteries are more prone to heat, each battery cell using contemporary Amperex Technology Co., Limited CTP technology is built in the upper and lower cases. The middle of the shell is filled with thermal grease, and a pressure or temperature sensor is arranged between the side wall of the battery cell and the shell. The former is used to detect the shape change of battery cells, and the latter is used to detect the temperature change, so as to eliminate the faulty battery cells and predict the runaway phenomenon of battery cell temperature measurement in advance.
3. Convenience and cost of after-sales maintenance. This is a question raised by Zhihu V Zhu Yulong. Because the batteries are directly fixed on the tray of the battery pack in some way (possibly by gluing), in the maintenance after the 4S shop, on the one hand, higher technical requirements are put forward; on the other hand, if one battery fails, the whole battery pack may need to be replaced.
4. Consistency of batteries. At present, it is speculated that the batteries using CTP technology may be connected in parallel and in series one after another. Whether this speculation is correct or not, this new technology does put forward higher requirements for the consistency of batteries. It also includes two aspects, one is the consistency in the battery production process, and the other is the consistency in the battery use process. The consistency of batteries has always been a difficult problem for domestic battery manufacturers.
■? Who else has CTP technology?
In addition to the above-mentioned Contemporary Ampere Technology Co., Ltd. and BYD, battery companies such as Cellular Energy and Guo Xuan Hi-Tech of Great Wall Motor are also developing their own CTP technologies.
According to Honeycomb Energy, their CTP technology has both non-module solutions and large-module solutions. CTP-G 1 Compared with the traditional 590 module of Honeycomb Energy, the number of parts is reduced by 24%, and the cost of each Wh battery is reduced by 0. 1 yuan; CTP-G2 improves 5%- 10% weight group efficiency, 5% space utilization rate, 22% parts number and 0.2 1 yuan /Wh battery cost. It's just that no more technical information has been disclosed yet.
On the other hand, BYD will officially release the "Super Lithium Iron Phosphate Battery" in March this year, and there may be more news about BYD CTP technology. BAIC New Energy is determined to take the lead in carrying the battery of CTP technology of Contemporary Ampere Technology Co., Ltd. on EU5, and we can also look forward to it. According to the test flow of power battery in the OEM, it is expected that at the end of Q 1 this year, we will see more technical highlights of battery announcement equipped with CTP technology.
■? Bangping branch
CTP technology can significantly improve the battery energy density and cruising range of pure electric vehicles, which is good for consumers. However, back to the topic of the article-can ——CTP technology make our cars safer and cheaper? So far, it is still a question mark. In terms of safety, the most basic and important battery consistency, there is still a big gap between domestic battery companies and Japanese and Korean battery companies; In terms of cost, it is not known whether the battery cost reduction brought by new technology can be reflected in the guided price of vehicles, because battery suppliers will have a greater say.
Of course, we have reason to believe that when CTP technology becomes a trend, our worries will no longer be a problem.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.