What is a polymer battery?

The positive and negative electrode materials used in polymer lithium-ion batteries are the same as those used in liquid lithium-ion batteries, and the working principles of the batteries are basically the same. The main difference between them lies in the electrolyte. Lithium-ion batteries use liquid electrolytes, while polymer lithium-ion batteries use solid polymer electrolytes instead. This polymer can be “dry” or “gel”. Currently, most of them use polymer gel electrolytes. Polymer lithium-ion batteries can be divided into three categories:

(1) Solid polymer electrolyte lithium-ion battery. The electrolyte is a mixture of polymer and salt. This type of battery has low ion conductivity at room temperature and is suitable for high temperature use.

(2) Gel polymer electrolyte lithium-ion battery. That is, plasticizers and other additives are added to the solid polymer electrolyte to improve the ion conductivity, so that the battery can be used at room temperature.

(3) Lithium-ion battery with polymer positive electrode material. It uses conductive polymer as the positive electrode material. Its specific energy is three times that of existing lithium-ion batteries and is the latest generation of lithium-ion batteries.

Because they use solid electrolytes instead of liquid electrolytes, polymer lithium-ion batteries offer advantages over liquid lithium-ion batteries, such as thinness, the ability to be made in any area and shape, and they also avoid safety issues like leakage, combustion, and explosion. Therefore, the battery casing can be made of aluminum-plastic composite film, thereby increasing the specific capacity of the entire battery. Polymer lithium-ion batteries can also use polymers as positive electrode materials, increasing their mass-to-energy ratio by over 50% compared to current liquid lithium-ion batteries. Furthermore, polymer lithium-ion batteries offer improvements over lithium-ion batteries in terms of operating voltage and charge-discharge cycle life. Based on these advantages, polymer lithium-ion batteries are hailed as the next generation of lithium-ion batteries.

Outlook on the Development Trends of Polymer Lithium-ion Batteries

Polymer lithium-ion batteries have been mature and commercialized globally for over two years. Although sales are growing rapidly, their market share remains below 10%, far below expectations compared to the 90% market share of liquid lithium batteries. Due to various factors, polymer batteries are generally priced higher than liquid lithium batteries. However, the competitive landscape in mobile devices is quietly shifting, particularly due to the design innovations they bring to mobile devices (such as superior performance in thicknesses under 4mm and large battery sizes). Polymer batteries are gaining recognition among designers of mobile phones, drones, and medical devices. Consequently, polymer manufacturers remain confident that the era of polymer batteries will surely arrive. The development trends of polymer lithium-ion batteries can be seen through the development of mobile phones. Currently, mobile phones are experiencing the following development trends:

(1)Mobile phones are developing towards miniaturization and ultra-thinness to facilitate the carrying of consumers;

(2)The personalization of mobile phone design is reflected in the fact that the design concept is no longer the original square shape. Irregular shapes, curves, and arc designs have become the mainstream of mobile phone design aesthetics;

(3) The use of color screens and the continuous increase in mobile phone functions. In order to make mobile phones smaller, reducing the battery size and thickness is the most effective way. Batteries with a thickness of less than 4mm have become the mainstream trend of thin mobile phone configuration. From the perspective of cost performance, this is the specialty of polymers. Mobile phones with irregular shapes, curves, and arc designs leave the effective space for batteries in irregular shapes. Liquid rectangular shapes cannot effectively utilize space and have low capacity, while laminated polymers can make the most effective use of this irregular space and increase capacity. Some manufacturers have launched arc-shaped batteries, trapezoidal batteries, and backpack batteries that can increase the capacity of mobile phones by more than 50% compared to liquid batteries of corresponding specifications. Mobile phones have more and more functions, resulting in more and more power consumption. The battery capacity is required to increase accordingly. Without increasing the thickness of the battery, polymer batteries have obvious advantages. Similarly, laptops, Bluetooth headsets, drones, medical equipment, military equipment, and other electronic devices are all moving towards mobility and portability, equipped with LCD displays. Their functionality is constantly increasing, and their screen sizes are constantly increasing. This provides unlimited business opportunities for polymer lithium-ion batteries.