Today, the electric vehicle industry has become a fertile ground for innovation. With the emergence of the 800V voltage platform, some new trends have emerged in power transmission: the all-in-one integrated system of battery chassis integration (CTC, Cell to Chassis) has greatly simplified the battery structure, maximizing performance while optimizing vehicle space; the miniaturization, high power and high voltage of the inverter have also made the laminated busbar (Laminated Busbar) with low inductance, high reliability and flexible layout, especially the CCS (CCS, Cells Contact System) using flexible printed circuit (FPC) has attracted much attention.

CTC becomes the key technology to win the competition

CTC further deepens the integration of battery system with electric vehicle power system and chassis. While improving structural efficiency, optimizing power distribution and significantly reducing energy consumption, it also reduces the number of parts, saves space, reduces vehicle weight, and increases battery life. It is considered to be the key technology that determines the success or failure of electric vehicle competition in the next stage.

As early as 2020, Tesla released the whole package packaging CTC solution, and Volvo, BYD, CATL, etc. are accelerating their layout. CATL is accelerating the research and development of CTC and plans to launch highly integrated CTC technology around 2025.

In April 2022, Leapmotor released the intelligent power battery chassis integration technology. The Leapmotor C01, which was officially launched at the end of September, became the first model in China equipped with CTC technology. The benefits of CTC are obvious, reducing modules and increasing battery capacity space by 14.5%. The elimination of the module level in the battery system saves structural parts, increases the lightweight coefficient of the body by 20% compared with the traditional solution, increases the torsional stiffness of the body by 25%, improves the handling, responsiveness and driving performance, and improves the active safety of the battery through software control.

CTC, which integrates battery cells, chassis, and large and small three-electric systems, can also integrate modules related to autonomous driving. The industrial chain involved is extremely complex and will bring a production and manufacturing revolution to the automotive industry.

Laminated busbars are born for the integration of electric drive systems

The electric drive system of electric vehicles is developing towards integration. Among the newly installed passenger cars, 3-in-1 and above electric drive systems have exceeded 50%, and the degree of integration is getting higher and higher. Highly integrated designs such as 6-in-1 and 7-in-1 are constantly emerging, such as Huawei's 7-in-1 DriveONE electric drive system.

In the electric drive system, high-voltage connections run through the power battery, electric drive system and other electronic components. The laminated busbar is an ideal choice for high-voltage connections that are superior to cables and traditional busbars. It has strong advantages in both electrical and mechanical properties and is regarded as the highway of the distribution system.

The electrical performance advantages of the laminated bus bar are mainly reflected in the current carrying capacity, creepage distance and stray inductance:

• Due to the high-frequency skin effect of the positive and negative copper busbar currents, the current carrying capacity of the laminated bus bar can be increased by 15% compared with the cable of the same area. At the same time, the multi-layer copper busbar is laminated with the insulating material to increase the conductive layer area, which increases the current carrying capacity and the heat dissipation surface.

  

• The laminated bus bar adopts an integrated design and a special edge sealing process, which can better control the creepage distance and is particularly suitable for the insulation performance requirements of the 800V high-voltage electric vehicle platform.

• The laminated busbar is made of positive and negative copper bars crimped together, which can offset the transient magnetic field generated by the positive and negative bus currents. Therefore, the stray inductance of the busbar can be greatly reduced, protecting the device from the threat of voltage spikes. Especially for the third-generation high-speed semiconductor device SiC application, lower stray inductance can effectively reduce the voltage spikes and oscillation problems that occur in the transient state of SiC switching.

  

Layered busbars have flexible design and high reliability mechanical characteristics:

• Unlike cables, the design of layered busbars can be diversified, such as L-shaped, U-shaped and strip-shaped. Its bending angle is more precise, the integrated shape is more closely fitted to the driver contour, and its rigid structure can better adapt to automated assembly, and the installation is simple, fast and error-free.

• During the driving of electric vehicles, the compact and stable integrated structure of the layered busbar can withstand long-term severe vibration under the harsh working conditions of the electric drive system and show excellent reliability in extreme temperature environments. The high-voltage connection is durable.

It can be seen that as system integration gradually deepens, the continuous miniaturization, high power and high voltage of inverters require low-inductance, reliable and flexible internal components. The laminated bus bar plays an important role in the power conversion of the inverter, the internal power battery and the power distribution.

Integrated busbar reduces costs and increases efficiency for battery systems

CCS CCS is also called battery cover assembly, which is used for new energy vehicles and energy storage battery module covers. It provides battery temperature sampling, cell voltage sampling functions and realizes high-voltage series and parallel connection of cells. It provides temperature and voltage to the BMS system through PCB’A, FPC and connector components. It is part of the BMS system.

The PCB’A or FPC of CCS CCS is used to replace the battery collection line. Previously, the collection line used the traditional copper wire harness solution. The harness is made of plastic surrounded by copper wire. When connecting the battery pack, each harness reaches one electrode. When the battery pack collects a lot of signals, many harnesses are required to cooperate, which takes up more space. In the pack assembly process, the traditional harness relies on workers to manually fix the port on the battery pack, and the degree of automation is low.

Compared with copper wire harnesses, PCB’A or FPC has outstanding advantages in safety, lightness, and regular layout due to its high integration and thin thickness. CCS CCS integrates the previously separately assembled plastic structural parts, copper and aluminum bars, etc. with PCB’A or FPC, greatly reducing the thickness, and can customize the structure, so that it can be directly placed on the battery pack by grabbing by a mechanical arm during assembly. It has a high degree of automation and is suitable for large-scale mass production.

Layered busbars and CCSs are all available – Zhejiang Saiying

Zhejiang Sine Power Technology Co., Ltd.. (hereinafter referred to as Zhejiang Saiying) has internationally leading technical strength. With advanced busbar electrical connector design concepts and manufacturing processes, it targets the international industry technology development trend and continuously improves the technical quality of its products.

Full range of laminated bus bars covering different applications

Zhejiang Saiying specializes in the development and production of laminated bus bars and busbar technologies. Its products cover many fields such as wind power generation, electric vehicles, rail transportation, communications, photovoltaic power generation, power grids and industrial frequency conversion. Its laminated bus bar products cover the following applications:

With advanced busbar design concepts and manufacturing processes, Zhejiang Saiying's rich laminated busbar products have better current bearing capacity and greatly improved heat dissipation effect; its minimal impedance and voltage drop can improve the overall system efficiency; at the same time, it also realizes complex installation requirements. Such advantages have won Zhejiang Saiying the recognition and praise of many industry customers.

Excellent performance CCS CCS

As the best choice for electric vehicles and energy storage battery packs, Zhejiang Saiying's CCSs made of raw materials such as FPC or printed circuit boards (PCBs) and conductive aluminum busbars adopt an integrated design of positive and negative terminals, which is easy to connect the battery cell electrodes and ensure the connection reliability between the battery cell and the battery management system (BMS).

Zhejiang Saiying's CCS CCS has functions such as battery power transmission, signal acquisition (voltage monitoring, temperature monitoring) and battery cell protection. It is also light, small in size and easy to assemble automatically. It is widely used in electric vehicle power battery packs and industrial energy storage (photovoltaic wind power storage, household energy storage) and other fields. At present, Zhejiang Saiying's powerPower battery products, CCS battery module side panels, energy storage products, etc. have been widely used in the industry.

Compared with the traditional battery module using wiring harness + aluminum bar + injection molding bracket, Zhejiang Saiying's blister bracket battery module (FPC component + aluminum bar + blister bracket) and hot pressing battery module (FPC/PCB component + aluminum bar + insulation film) provide customers with more choices.

Guarantee customer application

In the design, research and development, material selection, production and testing of busbars, Zhejiang Saiying always puts quality first. The company has a professional team with rich design experience, with professional backgrounds covering power electronics, mechanical mold design, materials, etc., and has technical capabilities such as busbar customized drawing engineering, power electronics product electrical/structural design support, conceptual product simulation analysis, and product reliability testing.

In terms of production capacity, Zhejiang Saiying's hot pressing laminating capacity includes 11 hot pressing machines with a total of 48 hot pressing openings, with an annual production capacity of more than 300,000 traditional composite busbars and more than 1 million CCSs. By the end of September 2022, the newly added automatic hot pressing production line will be dedicated to the production of CCSs, and the annual production capacity will increase by more than 1 million pieces.

To ensure product quality, Zhejiang Saiying's automated production line has functions such as electrical performance testing (on-off detection, resistance value detection), laser welding (nickel sheet and aluminum bar) and UV dispensing, curing (NTC and connector). The daily production capacity of a single production line can reach more than 4,000 pieces, including 4 production lines in the first phase of the project.

In terms of testing capabilities, Zhejiang Saiying has a full range of complete testing equipment such as universal material testing machine, salt spray testing machine, high current experimental console, digital bridge, constant temperature and humidity test chamber, automatic turret fiber hardness tester, shielded partial discharge test room and withstand voltage tester.

Zhejiang Saiying has passed ISO9001 and ISO14001-2015 quality management system certification and environmental management system certification, and has internationally advanced composite busbar automatic production lines and testing lines, which can fully guarantee the production efficiency and quality of composite busbar products.

After nearly 20 years of development, with the above-mentioned full guarantee, Zhejiang Saiying can provide system solutions and high-quality products for new energy power generation, electric vehicles, DC transmission, rail transportation, smart grid and industrial applications. The busbars produced by the company have passed the quality external audit assessment of customers such as CRRC, State Grid Intelligent Electric Research Institute and Fuji Electric, and have become their qualified suppliers. At the same time, CRRC, State Grid, ENVISION, NARI Group, Sungrow Power Supply, BYD and ZTE have become important partners of Zhejiang Saiying.

Looking to the Future

Facing the vast market space for electric vehicle power batteries and other market segment opportunities in the future, Zhejiang Saiying adheres to the business philosophy of "pursuing excellence and win-win future" and takes it as its mission to provide "first-class technology, high-quality products and refined services". It will make full use of the advantages of cascade busbars and CCSs, follow the market development, and provide customers with integrated and simple solutions to achieve more efficient and reliable power transmission applications.