The Frontline | Joining hands with Changan Automobile, Tai Lan New Energy releases diaphragm-free solid-state battery technology.

Text｜Han Yongchang 

Editor｜Zhang Bowen

New progress has been made in solid-state battery technology.

On November 7, Tai Lan New Energy and Changan Automobile jointly held a diaphragm-free solid-state lithium battery technology conference in Chongqing, and the two sides jointly launched the diaphragm-free solid-state lithium battery technology.

Compared with other semi-solid and solid-state products in the industry, Tai Lan New Energy has achieved a new breakthrough - eliminating the diaphragm. It is introduced that under the same conditions, the safety performance of Tai Lan's diaphragm-free semi-solid battery is significantly improved compared with that of liquid lithium battery.

In battery safety tests such as extrusion, high temperature, and overcharging, it far exceeds the requirements of the national standard. The diaphragm-free semi-solid product has passed the relevant certifications of GB38031-2020 "Safety Requirements for Traction Batteries for Electric Vehicles" and GB43854-2024 "Safety Technical Specifications for Lithium-ion Batteries for Electric Bicycles".

In terms of the improvement of comprehensive performance, the introduction of the diaphragm-free technology significantly enhances the compatibility and flexibility of the battery. The diaphragm-free solid-state battery technology can effectively inhibit the formation and penetration of lithium dendrites through the composite solid electrolyte layer of the electrode sheet and the in-situ submicron industrial film-making (ISFD) technology, further achieving intrinsic safety.

In addition, the conference also introduced that the diaphragm-free solid-state battery technology can achieve compatibility with a variety of material systems, including diversified material combinations such as NCM, LFP, and LMFP, enabling the battery to be flexibly customized according to different energy density requirements.

In terms of production cost control, the application of the diaphragm-free technology reduces the dependence on traditional diaphragm materials and some electrolyte. The raw material cost in the production process can be reduced by more than 10%, and the production efficiency is also improved to a certain extent.

As one of the four main materials of liquid batteries, the diaphragm is generally made of PE and PP materials, which is easy to shrink at high temperatures, easily causing a short circuit between the positive and negative electrodes, generating a large amount of heat, triggering the combustion of the electrolyte and the thermal decomposition of the electrode material, thereby leading to the battery catching fire or exploding.

In order to enhance the heat resistance of the diaphragm, the industry has carried out extensive research and implemented a number of improvement measures. Although the heat resistance of the diaphragm has been improved to a certain extent, the significant shrinkage of the diaphragm itself is still difficult to contain when the battery temperature rises above 200°C.

Not only that, these improvement measures are mostly "adding protection", which is the most common design concept of liquid batteries, such as adding an explosion-proof valve to the battery cell; at the PACK level, adding aerogel, adding mica sheets, adding a liquid cooling system, and adding a high-strength shell. However, excessive stacking not only significantly increases the cost and system complexity, but also cannot fundamentally solve the safety problems of lithium batteries caused by the characteristics of the diaphragm.

At the conference, Tai Lan New Energy first introduced the concept of "material reduction manufacturing" for lithium batteries and proposed the 4-3-2-1 technical route. Tai Lan New Energy takes three steps based on the four main materials of the current traditional liquid lithium-ion battery.

The first step is to eliminate the diaphragm and part of the electrolyte; this is the semi-solid battery product stage that Tai Lan first mass-produced and installed in vehicles. The second step is to completely eliminate the electrolyte; this is the all-solid product stage that Tai Lan will be the first to apply in some xifen zhuanye lingyu such as the low-altitude economy and other fields. The third step is to eliminate the negative electrode and only leave the active material that directly generates energy; this is the future, the anode-free all-solid product stage of Tai Lan.

Relying on the concept of "material reduction manufacturing", Tai Lan has determined a clear industrial path from liquid to semi-solid and then to all-solid batteries.

Compared with liquid batteries, solid-state batteries have higher energy density and safer guarantees. From the perspective of industrialization progress, the mass production time disclosed by the all-solid battery products released by the mainstream battery enterprises at home and abroad is basically between 2027 and 2030.

In contrast, semi-solid batteries show a more optimistic market prospect: semi-solid batteries can use more than 90% of the original production equipment for liquid lithium batteries; in terms of battery performance, the energy density and safety of semi-solid batteries have been significantly improved.

In this conference, Tai Lan clarified the mass production schedule. The diaphragm-free semi-solid battery is planned to be verified for vehicle installation in 2026 to meet the application requirements of new energy electric vehicles; the diaphragm-free all-solid battery is planned to be mass-produced in 2027.