Flexible battery-the artery of consumer electronics in the future

With the improvement of living standards and the development of technology, flexible electronics have received more and more attention. The progress of flexible electronic technology can profoundly change the product form in health, wearable, Internet of Everything, and even robotics, and has vast market potential.

Many companies have invested a lot of research and development, one after another early deployment of next-generation technology and new product development. Recently, foldable mobile phones have become a favored direction. Folding is the first step for electronic products to shift from traditional rigidity to flexibility.

Samsung Galaxy Fold and Huawei Mate X have brought foldable phones to the public's view and are truly commercial, but their solutions are all hinged in half. Although a whole piece of flexible OLED display is used, the rest is The device cannot be folded or bent. At present, the real limiting factor for flexible devices such as flexible mobile phones is no longer the screen itself but the innovation of flexible electronics, especially flexible batteries. The energy supply battery often occupies most of the device's volume, so it is also the most likely essential part in achieving true flexibility and bendability. In addition, wearable devices such as smartwatches and smart bracelets still use traditional rigid batteries, which are limited in size, resulting in battery life often being sacrificed. Therefore, large-capacity, high-flexibility flexible batteries are a revolutionary factor in foldable mobile phones and wearable devices.

1.Definition and advantages of flexible batteries

Flexible battery generally refer to batteries that can be bent and used repeatedly. Their properties include bendable, stretchable, foldable, and twistable; they can be lithium-ion batteries, zinc-manganese batteries or silver-zinc batteries, or even Supercapacitor. Since each part of the flexible battery undergoes certain deformation during the folding and stretching process, the materials and structure of each part of the flexible battery must maintain performance after several times of folding and stretching. Naturally, the technical requirements in this field are very high. High. After the current rigid lithium battery undergoes deformation, its performance will be severely damaged, and there may even be safety hazards. Therefore, flexible batteries require brand-new materials and structural designs.

Compared with traditional rigid batteries, flexible batteries have higher environmental adaptability, anti-collision performance, and better safety. Moreover, flexible batteries can make electronic products develop in a more ergonomic direction. Flexible batteries can significantly reduce the cost and volume of intelligent hardware, add new capabilities and improve existing capabilities, enabling innovative hardware and the physical world to achieve an unprecedented deep integration.

2.The market size of flexible batteries

The flexible electronics industry is considered to be the next major development trend of the electronics industry. The driving factors for its rapid development are the huge market demand and vigorous national policies. Many foreign countries have already formulated research plans for flexible electronics. Such as the US FDCASU plan, the European Union's Horizon Project, South Korea's "Korea Green I.T. National Strategy," and so on, China's Natural Science Foundation of China's 12th and 13th Five-Year Plan also includes flexible electronics as an important research area of ​​micro-nano manufacturing.

In addition to integrating electronic circuits, functional materials, micro-nano manufacturing, and other technology fields, flexible electronic technology also spans semiconductors, packaging, testing, textiles, chemicals, printed circuits, display panels, and other industries. It will drive a trillion-dollar market and assist Traditional sectors in enhancing the added value of industries and bringing revolutionary changes to the industrial structure and human life. According to forecasts by authoritative organizations, the flexible electronics industry will be worth US$46.94 billion in 2018 and US$301 billion in 2028, with a compound annual growth rate of nearly 30% from 2011 to 2028, and is in a trend of long-term rapid growth.

Flexible battery-the artery of consumer electronics in the future 〡 Mizuki Capital original
Figure 1: Flexible battery industry chain

Flexible battery are a vital part of the field of flexible electronics. They can be used in foldable mobile phones, wearable devices, bright clothing, and other areas and have a broad market demand. According to a research report on the 2020 global flexible battery market forecast issued by Markets and Markets, by 2020, the global flexible battery market is expected to reach 617 million U.S. dollars. From 2015 to 2020, flexible battery will grow at a compound annual growth rate of 53.68%. Increase. As a typical downstream industry of flexible battery, the wearable device industry is expected to ship 280 million units in 2021. As traditional hardware enters a bottleneck period and innovative applications of new technologies, wearable devices usher in a new period of rapid development. There will be a large-scale demand for flexible batteries.

However, the flexible battery industry still faces many challenges, and the biggest problem is technical issues. The flexible battery industry has high barriers to entry, and many issues such as materials, structures, and production processes need to be solved. At present, a lot of research work is still at the laboratory stage, and there are very few companies that can carry out mass production.

3.Technical direction of flexible batteries

The technical direction for realizing flexible or stretchable batteries is mainly the design of new structures and flexible materials. Specifically, there are primarily the following three categories:

3.1.Thin film battery

The basic principle of thin-film batteries is to use ultra-thin treatment of the materials in each battery layer to facilitate bending and, secondly, improve the cycle performance by modifying the material or electrolyte. Thin-film batteries mainly represent lithium ceramic batteries from Taiwan Huineng and zinc polymer batteries from Imprint Energy in the United States. The advantage of this kind of battery is that it can achieve a certain degree of bending and is ultra-thin (<1mm); the disadvantage is that I.T. cannot stretch it, the life decays quickly after turning, the capacity is small (milliamp-hour level), and the cost is high.

3.2.Printed battery (paper battery)

Like thin-film batteries, paper batteries are batteries that use thin-film as a carrier. The difference is that a special ink made of conductive materials and carbon nanomaterials is coated on the film during the preparation process. The characteristics of thin-film printed paper batteries are soft, light, and thin. Although they have lower power than thin-film batteries, they are more environmentally friendly—generally a disposable battery.

Paper batteries belong to printed electronics, and all of their components or parts are completed by printing production methods. At the same time, printed electronic products are two-dimensional and have flexible characteristics.

3.3.New structure design battery (large capacity flexible battery)

Thin-film batteries and printed batteries are limited by volume and can only achieve low-power products. And more application scenarios have more demand for immense power. This makes non-thin film 3D flexible batteries a hot market. For example, the current popular large-capacity flexible, stretchable battery realized by the island bridge structure. The principle of this battery is the series-parallel structure of the battery pack. The difficulty lies in the high conductivity and the reliable link between the batteries, which can stretch and bent, and the external Protect the pack's design. The advantage of this type of battery is that it can stretch, bend, and twist. When turning, only bending the connector does not affect the life of the battery itself. It has a large capacity (ampere-hour level) and low cost; the disadvantage is that the local softness is not as good as an ultra-thin battery. Be small. There is also an origami structure, which folds 2D-dimensional paper into various shapes in 3D space by folding and bending. This origami technology is applied to lithium-ion batteries, and the current collector, positive electrode, negative electrode, etc., are folded according to different folding angles. When stretched and bent, the battery can withstand a lot of pressure due to the folding effect and has good elasticity. Will not affect performance. In addition, they often adopt a wave-shaped structure, that is, a wave-shaped stretchable structure. The active material is applied to the wave-shaped metal pole piece to make a stretchable electrode. The lithium battery based on this structure has been stretched and bent many times. It can still maintain a good cycle capacity.

Ultra-thin batteries are generally used in thin electronic products such as electronic cards, printed batteries are typically used in single-use scenarios such as RFID tags, and large-capacity flexible batteries are mainly used in intelligent electronic products such as watches and mobile phones that require large capacity. Superior.

4.The competitive landscape of flexible batteries

The flexible battery market is still emerging, and the participating players are mainly traditional battery manufacturers, technology giants, and start-up companies. However, there is currently no dominant manufacturer globally, and the gap between companies is not large, and they are basically in the R&D stage.

From a regional perspective, the current research and development of flexible batteries are mainly concentrated in the United States, South Korea, and Taiwan, such as Imprint Energy in the United States, Hui Neng Taiwan, L.G. Chem in South Korea, etc. Technology giants such as Apple, Samsung, and Panasonic are also actively deploying flexible batteries. Mainland China has made certain developments in the field of paper batteries. Listed companies such as Evergreen and Jiulong Industrial have been able to achieve mass production. Several start-ups have also emerged in other technical directions, such as Beijing Xujiang Technology Co., Ltd., Soft Electronics Technology, and Jizhan Technology. At the same time, significant scientific research institutions are also developing new technological directions.

The following will briefly analyze and compare the products and company dynamics of several major developers in the field of flexible batteries:

Taiwan Huineng

FLCB soft plate lithium ceramic battery

1. The solid-state lithium ceramic battery is different from the liquid electrolyte used in the available lithium battery. It will not leak even if it is broken, hit, punctured, or burned and will not catch fire, burn, or explode. Good safety performance
2. Ultra-thin, the thinnest can reach 0.38 mm
3. The battery density is not as high as that of lithium batteries. The 33mm34mm0.38mm lithium ceramic battery has a capacity of 10.5mAh and an energy density of 91Wh/L.
4. It is not flexible; it can only be bent, and cannot be stretched, compressed, or twisted.

In the second half of 2018, build the world's first super factory of solid-state lithium ceramic batteries.

South Korea L.G. Chem

Cable battery

1. It has excellent flexibility and can withstand a certain degree of stretching
2. It is more flexible and does not need to be placed inside electronic equipment like traditional lithium-ion batteries. It can be placed anywhere and can be well integrated into the product design.
3. Cable battery has small capacity and high production cost
4. No energy production yet

Imprint Energy, USA

Zinc polymer battery

1. Ultra-thin, good dynamic bending safety performance
2. Zinc is less toxic than lithium batteries and is a safer choice for equipment worn on humans

The ultra-thin characteristics limit the battery capacity, and the safety performance of the zinc battery still needs long-term market inspection. Long product conversion time

Join hands with Semtech to enter the field of Internet of Things

Jiangsu Enfusai Printing Electronics Co., Ltd.

Paper battery

1. Has been mass-produced and has been used in RFID tags, medical and other fields

It can customize 2. The size, thickness, and shape are according to users' needs, and it can adjust the position of the positive and negative electrodes of the battery.

1. The paper battery is for one-time use and cannot be recharged
2. The power is small, and the usage scenarios are limited. It can only apply to RFID electronic tags, sensors, smart cards, innovative packaging, etc.
3. Complete the wholly-owned acquisition of Enfucell in Finland in 2018
4. Received 70 million RMB in financing in 2018

HOPPT BATTERY

3D printing battery

1. Similar 3D printing process and nanofiber reinforcement technology
2. Flexible lithium battery has the characteristics of light, thin and flexible

5.The future development of flexible batteries

At present, flexible batteries still have a long way to go in electrochemical performance indicators such as battery capacity, energy density, and cycle life. The batteries developed in the existing laboratories generally have high process requirements, low production efficiency, and high cost, which are unsuitable for large-scale industrial production. In the future, looking for flexible electrode materials and solid electrolytes with excellent comprehensive performance, innovative battery structure design, and the development of new solid-state battery preparation processes are breakthrough directions.

In addition, the most significant pain point of the current battery industry is battery life. In the future, battery manufacturers that can achieve an advantageous position must solve the problem of battery life and flexible production at the same time. The application of new energy sources (such as solar energy and bioenergy) or new materials (such as graphene) is expected to solve these two problems simultaneously.

Flexible batteries are becoming the aorta of consumer electronics in the future. In the foreseeable future, technological breakthroughs in the entire field of flexible electronics represented by flexible batteries will inevitably bring about tremendous changes in upstream and downstream industries.