High-quality hydrogen storage density is a significant technological bottleneck that must be overcome to achieve the commercial application of hydrogen energy. It directly affects the efficiency, economy, and promotion value of hydrogen fuel cell vehicles. Currently, many countries, including Japan, South Korea, and those in Europe and America, have taken the lead in mass-producing Type IV hydrogen storage cylinders for the hydrogen fuel cell vehicle market, achieving a mass hydrogen storage density of over 5.5wt%. However, due to various factors, the domestic market mainly uses Type III cylinders, with a hydrogen storage density of only 3.9wt%. However, with the increasing demand for hydrogen fuel cell vehicles, the continuous improvement of domestic standards and regulations, and the breakthroughs made by domestic companies in Type IV hydrogen storage cylinder technology in recent years, this situation is changing.

　　Recently, Weishi Energy's independently developed second-generation 70MPa-57L Type IV hydrogen storage cylinder has made a breakthrough, achieving a mass hydrogen storage density of 6.1wt%, exceeding the target value of 5.5wt% set by the US Department of Energy (DOE) for 2025 and surpassing the indicators of similar products from mainstream international brands, reaching a world-leading level. It is mainly suitable for on-board hydrogen storage systems in hydrogen fuel cell passenger vehicles.

　　At the same time, based on the application needs of different market scenarios and customer types, Weishi Energy's full range of Type IV hydrogen storage cylinders are being developed simultaneously, covering working pressures of 35MPa and 70MPa, including product series such as 70MPa-23L and 35MPa-210L. The mass hydrogen storage density of some commercial vehicle-mounted Type IV hydrogen storage cylinders can reach 6.8wt%. The entire product line has achieved 100% independent control of key core technologies, and 100% domestic production of key raw materials (such as carbon fiber) and core supporting components (such as bottle mouth valves and inner liners), reducing the overall cost by 20%. It also has advantages in lightweight, long lifespan, and high safety, and will be released soon. Customized product development is available, widely applicable to fuel cell passenger vehicles, commercial vehicles (heavy trucks, buses, refrigerated trucks), ships, and other scenarios and fields.

　　From a technical perspective, higher pressure places higher demands on the overall performance of core components such as hydrogen storage cylinders and valves, making it more difficult to achieve key technologies such as sealing performance, permeability, hydrogen-related performance at extreme temperatures, hydrogen-related fatigue life, product reliability, and safety. Especially as the demonstration scenarios and scale of hydrogen fuel cell vehicles continue to expand, and the actual application scenarios of products expand, higher demands are placed on the performance of Type IV hydrogen storage cylinders.

　　In the development of Type IV hydrogen storage cylinders, Weishi Energy, based on the application needs of different operating conditions of clients, combined with the particularity of hydrogen medium and the matching characteristics of hydrogen storage system functions and structures, gave full play to its advantages in key technology research and development in the hydrogen storage field. Through numerous feasible design schemes and experimental verifications, focusing on the application of "new materials, new technologies, and new processes," it has successively overcome many key technical challenges in Type IV hydrogen storage cylinders.

　　Tackling New Material Development to Eliminate Application Limitations from the Source

　　Weishi Energy focuses on the development and application of key materials, conducting in-depth cooperation with many well-known domestic universities, research institutes, and supply chain partners. It focuses on tackling "bottleneck" technical challenges such as the hydrogen barrier properties of plastic inner liner raw materials, the bulging, bending, and collapse that easily occur in the inner liner during venting, the chemical composition control and heat treatment state of aerospace-grade aluminum alloy, and the processing of carbon fiber prepreg and the performance of the accompanying resin. It gradually overcomes these challenges, eliminating from the source the application limitations brought about by the import of core materials and high costs.

　　To date, Weishi Energy has achieved the research and development and application verification of key common technologies, including the selection of inner liner polymer raw materials, high-strength new fiber prepreg, and accompanying resin formulas. This provides important guarantees for the excellent mechanical properties, quality stability, and domestic substitution of hydrogen storage cylinders, and has significant scientific significance and engineering application value.

　　Innovative Structural Design Improves Product Reliability

　　While the selection of new materials is important, to truly reflect the quality stability, consistency, and applicability of hydrogen storage cylinders, it is essential to have a scientific structural design.

　　The connection structure between the metal valve seat and the valve at the bottle mouth abandons the conventional complex multi-component structural design. Through independent innovation in the inner liner and valve seat sealing structure and interface design, an integrated "direct connection" is achieved. The metal valve seat uses a lightweight structural design, and the appearance curve smoothly connects with the inner liner head curve. It fully considers the interaction between the valve seat and the carbon fiber composite material during external impact, achieving anti-slip and anti-rotation. Coupled with finite element analysis software, it achieves an ultimate "lightweight" design under a scientific safety factor. The weight is reduced by 40% compared to competing products, and an innovative high-performance "sealing" solution is used to reduce the risk of hydrogen leakage and permeation, further improving product safety.

　　At the same time, in terms of carbon fiber layer design, by using scientific design methods such as genetic algorithms and simulation software, the winding angle and layer sequence are optimized to maximize the fiber strength and toughness of the carbon fiber prepreg, ensuring the compressive strength and reliability of the hydrogen storage cylinder throughout the entire life cycle of the hydrogen fuel cell vehicle.

　　Revolutionizing the "Dry Winding" Process to Help the Industry Reduce Costs and Increase Efficiency

　　Based on the selection of new materials and new structural designs, Weishi Energy boldly innovated the full-process production process design. In terms of inner liner forming technology, it uses injection molding and welding technology, which is rarely used in China, enabling the inner liner to achieve a higher level of uniformity and dimensional stability in the industry.

　　At the same time, the company pioneered a prepreg "dry" winding process, with the coefficient of variation of product performance indicators controlled within 2%-3%. The winding efficiency is increased by more than 80% compared to the wet method, the curing time is shortened by 30%, and the fatigue test life is >44000 times. While achieving lightweight goals, it further ensures the utilization rate of carbon fiber strength, burst strength, and pressure cycle life consistency, effectively solving key problems such as inner liner wrinkles and bending, and significantly improving mass hydrogen storage density, production efficiency, and quality. Moreover, there are no phenomena such as dripping or leaking glue during the winding process, making the production environment more friendly. This provides effective data support and operational experience for subsequent mass production and market supply.

　　Currently, Weishi Energy's independently developed second-generation Type IV hydrogen storage cylinder series has successively completed several key test projects, including fire tests, durability tests, and performance tests. The construction of the production line is nearing completion, and the relevant work for the "three new" review is being carried out in an orderly manner. It is understood that this is another major scientific and technological innovation achievement of Weishi Energy focusing on the hydrogen energy storage and transportation field, using "bottleneck" technologies as a breakthrough, following the 70MPa hydrogen storage valve product. This marks that the company has the ability to design, develop, and manufacture key technologies and core components of complete sets of hydrogen storage systems, from product development to application, in the hydrogen storage technology field. It will also help expand its industrial chain supply and application layout, further meet the growing demand of the high-pressure hydrogen storage and transportation market, provide more professional, high-quality, and cost-effective solutions for industry customers, and effectively promote the accelerated domestic substitution of hydrogen energy storage equipment, opening up new space for cost reduction and efficiency improvement.

　　Currently, benefiting from the implementation of policies for hydrogen fuel cell vehicle demonstration city clusters and the impact of the Beijing Winter Olympics, China is transitioning to Type IV and the market space is continuously expanding. In 2023, China is expected to begin implementing national standards for Type IV hydrogen storage cylinders, potentially becoming the world's largest market for vehicle-mounted hydrogen storage cylinders, making domestic production imperative. During this process, improving the comprehensive performance of Type IV hydrogen storage cylinders through technological breakthroughs, and promoting cost reduction and large-scale application in the market will continue to test the entire industry.

　　As the competition for Type IV hydrogen storage cylinders heats up, Weishi Energy has taken the lead in solving the problem of high-quality hydrogen storage density, using tangible results to promote key technological innovations in the industrial chain, promoting domestic production, industrialization, and cost reduction in market applications, injecting a shot of confidence into the hydrogen energy industry and technological innovation teams entering a new stage of development.