CTP technology, while improving the energy density of battery pack systems and vehicle driving range, may also have a more profound impact on power batteries and new energy vehicles.
Beginning in the second half of 2019, CATL’s CTP (Cell?to?Pack) and BYD’s blade battery technology have entered the public eye and attracted much attention from the industry. ?
First, ?CTP, system process innovation based on high-quality batteries
Simply speaking, the technical ideas of Ningde CTP and blade battery (GCTP) are consistent: in the original Based on some battery chemical systems, through the optimization of battery cell design and battery pack integration form, the original three-layer structure of cell-module-battery pack is improved to one composed of large cells/large modules. Single-battery pack two-layer structure.
CATL CTP battery pack and BYD blade battery?
The grouping efficiency of traditional battery packs is a bottleneck in improving the energy density of battery systems. Such as the schematic diagram of a typical battery pack "three-layer structure":
The left side of the picture is a battery module (Module) composed of battery cells (Cell). In addition to the battery cells, it also includes Metal cover end plates, wire harnesses, adhesives, thermal conductive glue, module control units and other components are combined together to form a battery module. On the right side of the picture is a battery pack (Pack) composed of several modules. The components at the battery pack level include thermal management systems, wiring harnesses, controllers, casings, etc. Typical battery pack structure, source: Audi A3 battery pack structure
This three-layer structure is common to typical power battery packs. The reason why there is a "module" is to protect, support, It integrates battery cells, and on the other hand, each module independently manages some of the battery cells, which helps temperature control, prevents the spread of thermal runaway, and facilitates maintenance. However, the existence of modules reduces the space utilization of the entire battery pack, resulting in a low level of group efficiency - the more modules, the more components, and the lower the group efficiency. While the single energy density has exceeded 300Wh/kg, due to the traditional battery pack grouping method, the energy density at the battery system level is still around 160Wh/kg. At the same time, due to safety risks of high-nickel batteries, some manufacturers have suggested limiting the use range of high-nickel battery SOC, which actually reduces the energy of high-nickel batteries.
Therefore, making modules larger or smaller, or even having no modules, has been the main focus of battery system process design in recent years. The large module of Tesla Model 3 also reflects this. A trend. But at the same time, just because the module has the function of protecting the battery, reducing risks, and facilitating maintenance, "module-less" has higher technical difficulties, which means higher requirements for the quality and consistency of the battery cells. Therefore, the module-free technology of CATL and BYD is not only an outstanding innovation at the battery system process level, but also reflects the technical level of battery cell design and manufacturing. For second-tier battery manufacturers with relatively backward technology, CTP undoubtedly brings higher technical threshold and competitive pressure.
The large module battery pack of Tesla Model 3 also reflects the technological trend of de-modularization
The improvement of group efficiency gives CTP many advantages :
1. Long mileage: The increase in battery pack energy density directly improves the vehicle's driving range. Under the same battery chemical system conditions, the system energy density of Ningde CTP battery packs has been improved by 10-15; while BYD Blade Battery has increased the volumetric energy density of lithium iron phosphate battery (LFP) packs by 50 to 160Wh/kg. NCM batteries are also very competitive.
2. High safety: Energy density has been the battery performance that battery manufacturers have focused most on in the past few years. Before CTP, the improvement in energy density was mainly achieved through the improvement of the ternary battery chemical system. , and with the continuous upgrading of high-nickel systems, the risks to battery safety are rising.
The improvement in energy density of CTP at the battery pack level means that sufficient driving range can be achieved by using ordinary ternary or even lithium iron phosphate batteries with mature safety at the battery cell level. Under the same mileage effect, the safety of the entire vehicle is undoubtedly improved. Of course, for CTP with high nickel systems, safety risks still exist. ?
3. Low cost: From a cost perspective, due to the elimination of wiring harnesses, covers and other components in the module, the number of parts in the entire battery pack has been reduced by 40%, and production efficiency has increased by 50%. The material cost and manufacturing cost of CTP battery packs will be improved. If lower-cost lithium iron phosphate batteries are used, the cost of the entire battery pack will be further reduced compared to traditional ternary battery packs.
Although there may be technical challenges such as battery pack strength and maintenance2; the above advantages will become more significant with the extensive exploration and use of CTP technology. As far as we know, mass-produced models that have been equipped or will be equipped with CTP include BAIC EU5, Volkswagen Latin American Commercial Vehicle e-Delivery, NIO 100kWh battery pack and BYD Han.
Mass-produced models equipped with CTP technology
2. The impact of CTP on the industry structure and new technologies
Although the advantages are obvious, for OEMs , CTP technology may not be 100% good news.
In the development of new energy vehicles, the "technical dividing line" between the OEM and the battery factory is generally at the battery pack level. Passenger car OEMs and commercial vehicle manufacturers with weaker technical capabilities will generally directly use battery packs delivered by battery factories; while OEMs with stronger technical capabilities will choose to lead the development of battery packs based on the battery modules delivered by battery factories. Take SAIC as an example. The two joint ventures "Times SAIC" and "SAIC Times" formed by SAIC and CATL are battery factories and battery pack factories led by CATL and SAIC respectively. The necessity for car companies to develop their own battery packs is obvious: on the one hand, it can better match the design of the vehicle, and on the other hand, it also masters the battery pack technology and retains the technology and value related to the vehicle within the system. As battery technology becomes more and more important, leading passenger car OEMs are increasingly inclined to strengthen their voice in battery technology.
However, CTP technology means that at the battery pack level, battery manufacturers will regain the upper hand and their value in the industry chain will further increase. Judging from the current public information, it is difficult for passenger cars to adopt battery packs standardized for commercial vehicles. Ningde's CTP technology needs to be deeply customized for the vehicle model. The OEM needs to at least jointly develop it with the battery factory, or directly use it to develop the battery pack. The battery pack is completely handed over to the battery factory. This factor may affect the prospects for the popularization of CTP technology in vehicle loading, but a more likely scenario is that OEMs may differentiate into three types of options:
1. Some OEMs will The battery pack will be completely handed over to the battery factory to develop CTP, and it will no longer lead the development of battery packs;
2. Some OEMs will still maintain the existing technical system and maintain the three-layer battery pack structure. The products use high-nickel batteries and do not use CTP technology solutions;
3.? Some OEMs have further strengthened their battery technology capabilities, further integrated upstream, and may launch their own CTP solutions in the future.
The occurrence of this scenario will promote the differentiation of vehicle products in the electric vehicle market. It will not be expanded upon here for the time being.
On the other hand, CTP may also have an impact on the next generation of battery technology.
Looking back three years ago from today, the battery technology development path from 2017 to 2020 is very clear in the plan - by gradually increasing the nickel ratio of the cathode chemical system, from 523 to 622 to 811 , increasing the energy density of the battery cell to 300Wh/kg. The realization of this development path relies on the rapid improvement of production technology, and it is actually realized faster than expected. But the technical expectations in the future: from high-nickel silicon-carbon anodes, to solid-state batteries, to solid-state battery lithium anodes, and even lithium-air batteries... the technological development of this series of battery cells at the individual level, whether in theory or products, All came more slowly than expected.
Before 2018, the industry's predictions for the commercialization of solid-state batteries were generally between 2020 and 2025; but by 2020, the commercialization of solid-state batteries is expected to have been postponed to after 2025.
Around 2015, the performance of next-generation battery samples manufactured by Toyota and the expected mass production time of next-generation battery cell technology. So far, it still takes time for next-generation battery technology to reach mass production. (Source: ATZ?elektronik?worldwide)
The commercialization of next-generation battery technology depends on the maturity of laboratory technology on the one hand; on the other hand, it also faces competition with existing technologies. If solid-state batteries only improve the safety of existing batteries, but have disadvantages in energy density, capacity, charge and discharge, and cost, it will be difficult to compete with already large-scale mass-produced battery technology. In other words, the next generation technology needs to be better than the existing technology in many aspects to have the possibility of commercial success. The more mature existing technologies become, the greater the challenges faced by new technologies. The promotion of CTP technology will further enhance the potential of existing mature technologies and raise the competitive threshold that solid-state batteries will face. It also means that the mass production date of solid-state batteries may be pushed further.
3. Summary
Although CTP and blade batteries still face technical and commercial challenges, CTP is undoubtedly worth looking forward to and will be destined to become the highlight of the era of change. chapter. Whether it is better pure electric vehicle products or more competitive OEMs, they will eventually stand out in the tide. Let us work together.
This article is written by a special author of EV Vision:
About the author: Yao Changsheng holds a bachelor's degree and a Ph.D. in the Department of Automotive Engineering, Tsinghua University, and is engaged in research on new energy vehicle power systems.
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.