Hengchuan New Energy Yang Liu: Long life high security energy storage system diaphragm matching solution

China Energy Storage Network: From May 24 to 26, the 13th China International Energy Storage Conference was held in Hangzhou under the joint guidance of the Department of Energy Conservation and Comprehensive Utilization of the Ministry of Industry and Information Technology and the Department of Energy Conservation and Science and Technology Equipment of the National Energy Administration, and sponsored by the China Chemical and Physical Power Industry Association and jointly supported by more than 240 organizations.

More than 1011 industry chain supply chain enterprises from different fields such as industry authorities, domestic and foreign institutions in China, scientific research units, power grid enterprises, power generation enterprises, system integrators, financial institutions, etc., 5417 guests attended the conference, among which 245 enterprises displayed energy storage products, covering system integration, cores, PCS, BMS, containers, fire protection, testing and certification The whole industry chain of new energy storage, etc.

In the afternoon of May 25, Yang Liu, senior development manager of Taizhou Hengchuan New Energy Materials Technology Co., Ltd. was invited to share the theme report in the special session of long-time energy storage technology and application, the report is entitled "Long Life High Safety Energy Storage System Diaphragm Matching Solution". The following is the main content of the report:

Yang Liu: Dear leaders, experts and guests, good afternoon!

I am Yang Liu from Taizhou Hengchuan New Energy Materials Technology Co., Ltd. and I am honored to have the opportunity to meet with you all to discuss the knowledge in the field of energy storage, today I bring you "Matching solution for long life, high safety energy storage system diaphragm", mainly used in electrochemical energy storage lithium-ion batteries, please experts Please correct me.

Today I will share with you specifically from several aspects of the application of diaphragms in electrochemical, first of all, the status of electrochemical energy storage, here is only a brief statement, before this experts have shared a lot. Electrochemical energy storage from the cumulative data in 2022, currently amounting to more than 40 GW, in 2022 the annual growth rate reached 200% of the horrible growth. The proportion of lithium-ion batteries in it has been showing more than 90%, and it is expected to exceed 100 GW in about 2030, which is the current general status of the industry.

Lithium battery energy storage shows a rapid growth trend, but the problems we are currently facing should not be underestimated, the main problems we face may revolve around cycle life, safety features, including cost and price, technical thresholds and so on, which have become a huge challenge for lithium storage. To cycle life, for example, the current market roughly used some lithium iron phosphate batteries, ternary batteries, including lead-acid batteries have a certain limit of cycle life. After facing capacity decay, we may face problems such as battery death, or even safety.

What are the factors affecting the life and safety performance of lithium batteries! This is a problem that we need to think deeply about lithium batteries. In terms of the structure of lithium batteries, they can be roughly divided into positive and negative electrodes, diaphragm, electrolyte, shell parts. Each of the components will have an impact on the cycle and safety of lithium batteries, which requires experts in various fields to explore and solve.

Taizhou Hengchuan New Energy Material Technology Co., Ltd. is a high-tech enterprise focusing on the production of lithium wet diaphragm, for the diaphragm level, we are also facing great challenges. From the market requirements of lithium batteries, requiring high energy density, safety performance and long cycle life, including low self-discharge requirements, diaphragm in these conditions on the basis of also facing a huge challenge, diaphragm is gradually moving towards lighter and thinner, corresponding to improve the energy density of the battery, high strength and heat resistance performance corresponding to the requirements of the battery safety performance. High liquid retention performance for the development of long cycle life of the battery.

Faced with these challenges, but also looking ahead to a once-in-a-lifetime opportunity to look back at the entire battery cost composition, diaphragm materials have been maintaining a stable proportion, with the rapid development of the new energy vehicle industry, electrochemical energy storage gradually into the development of industrial scale stage, the diaphragm industry is bound to usher in the spring again.

Facing the challenges and opportunities, Hengyuan has put forward its own thinking on diaphragm for long life and high safety electrochemical energy storage system. For base film, we have researched a variety of high mechanical performance base films through dual optimization of formulation and process, multi-layer co-extrusion, and PP wet process technology. The ultra-low heat shrinkage coating film has been specially developed by using ultra-low heat shrinkage base material plus special coating formulation process. In addition to R&D, Henchuan also strives for perfection in quality control of the whole process of film making. Considering the impact of foreign matter on the long cycle and safety performance of the battery, in addition to the regular inspection and testing items, Henchuan has also established a special foreign matter control system, especially for the management of magnetic foreign matter, we have set up a professional team to develop a metal foreign matter map and FEMA from the perspective of human-machine measurement, law and environment to prevent and control in all aspects.

Hengyuan diaphragm development, in terms of energy storage, we mainly focus on 9μm, 12μm and 14μm, 16μm base film generally does not increase the coating, mainly in the high strength and high puncture properties to achieve the industry's current best. For the leftmost 16μm base film, the current puncture strength can be 900gf, compared with 800gf in the industry, which is more than ten points of improvement. And about the base film heat shrinkage we have done a lot of research, test base film 105 ℃ heat shrinkage, the average level is below 2%, including the two-way tensile strength can reach 3000kgf/cm2, currently in the field of energy storage applications more.

At the same time, using the formulation and process matching, the performance of the diaphragm can be fine-tuned to ensure high mechanical strength, while ensuring porosity and thermal shrinkage performance.

The second one to show you is the multilayer co-extrusion technology. Coextrusion technology comes from the difference between the low closed pore temperature and high breakage temperature required by the client, the base material of ordinary diaphragm is PE, according to the basic characteristics of PE material, its melting point is roughly around 135 ℃, so if we use pure PE-based materials for diaphragm, its closed pore temperature can only be 135 ℃ -140 ℃. Through multi-layer co-extrusion technology, we can introduce different raw materials to break the film temperature and closed cell temperature to pull away from a certain range, so that the battery is in a safer working condition.

This is the substrate we do ultra-low heat shrinkage, diaphragm industry, we are measuring 90 ℃, 105 ℃ and 120 ℃ heat shrinkage, Henchuan in addition to research 130 ℃ heat shrinkage, what kind of substrate in the case of no additional coating layer, the base material can be better heat shrinkage, after matching different coating layers, heat shrinkage can reach a longer run level. Compared with peers and the market, the current market 130 ℃ heat shrinkage can be achieved at a level of about 15%, the current research Henchuan can achieve the level of 5% or less.

Next is the introduction of high temperature alumina coated film coating, currently the market is used more 130 ℃ heat shrinkage, which is in line with the application of the battery environment, including some electrolyte, positive and negative electrode analysis temperature are at 130 ℃, but for higher safety, we are committed to the diaphragm heat shrinkage to do higher, so that the battery in a more stable operating condition. Regarding the 105℃ heat shrinkage, it is obvious that the size of the diaphragm does not change significantly after baking at high temperature, including the surface wrinkles of the diaphragm, which still remains flat.

Hengyuan is an innovator of high-performance lithium battery diaphragm technology, the current cumulative investment reached more than 6 billion, this year's production capacity is 900 million ㎡, next year's production capacity release will reach more than 2 billion ㎡, the current base is more than 2,000 acres, mature products reached 60 +, including patents and R & D are equipped with a very mature team.

Henchuan was established in 2018, diaphragm is a heavy asset industry, we have reached cooperation with the government from 2018 to introduce the Zhongguancun investment, Sequoia Capital investment to ensure the establishment of the entire diaphragm base. At present, Hengyuan has three bases, including Taizhou headquarters, Jiangxi Yichun and Anhui Anqing base. Taizhou headquarters currently has 900 million square meters of production capacity, Jiangxi planning capacity of 1.8 billion square meters, Anqing planning capacity of 3.3 billion square meters. This is Hengyuan's current production capacity planning, at the end of 2023, will be released to more than 2 billion ㎡, in 2025 is expected to build a large lithium diaphragm manufacturer of 10 billion ㎡. At present, our product structure, from base film to coated film to reach the whole process production, Henchuan is committed to the production of 5-16 micron base film and a variety of coated film, PMA coating, ultra-thin fiber coated film, etc.

The next thing we share with you is Henchuan's equipment. In terms of the whole diaphragm industry at present, it is common to use 4m+ and 6m+ stretch production line equipment. Henchuan proposed in 2018 the finished product width of 7.5 meters, the overall equipment width is 8 meters + large width production line. The equipment advantage will definitely bring the cost advantage. The product width is doubled, but the number of employees does not need to be increased, and the production capacity is doubled under the condition that only the energy consumption is increased by 20% or less, so that cost reduction can be achieved.

Finally, to summarize our features, roughly divided into the following: three self-iteration of production line equipment (the whole process, the whole process, key equipment self-research); in the lithium diaphragm application scenario knowledge base, can be deeply customized product output; product features are obvious, including low heat shrinkage, mechanical strength and high impact safety performance, can reach a high level in the industry; perfect quality control guarantee system to ensure that the diaphragm Product quality to meet the needs of customers and the market; R & D team members knowledge and experience, since 2010 in new energy chemistry and other fields have begun related research.

The above is all I have shared today, thank you for listening.