Safety protection of ternary lithium batteries enters the 2.0 era

The safety of electric vehicle power batteries has always been a core concern for consumers. After all, when most people see a natural car on the road, their first reaction is almost always, "The electric car caught fire again." Although the number of spontaneous combustion accidents of fuel vehicles exceeds that of electric vehicles in terms of both proportion and absolute number, the rapid spontaneous combustion speed, fierce fire, and tragic consequences of electric vehicles have made people full of worries and concerns about battery safety.

Therefore, the entire electric vehicle industry has been working hard and making continuous progress on the safety of power batteries. Last year, lithium iron phosphate batteries, with their inherent safety advantages, significantly increased their market share after improving their energy density disadvantages. In the 342nd batch of new cars announced by the Ministry of Industry and Information Technology, the proportion of lithium iron phosphate batteries installed exceeded that of ternary lithium batteries, indicating that after the energy density reaches a certain level, the pursuit of safety has become a priority for car companies in choosing power battery products.

Of course, the advantages of ternary lithium batteries, such as higher energy density, better low-temperature performance, large operating voltage bandwidth, and more accurate SOC monitoring, make it impossible for battery manufacturers and automobile OEMs to give up this technical route. Therefore, in 2021, a number of manufacturers have successively released new safety protection technologies for ternary lithium power batteries, upgrading the safety protection of ternary lithium batteries to the 2.0 era, and fully entering the "no fire, no explosion" stage. Today, the battery protection technology that Mr. Bang wants to talk about is more advanced, with one more "no smoke" than the two "no".

The battery that achieves "no smoke, no fire, no explosion" is the new battery pack used in the Lantu FREE pure electric model released by Lantu today. In order to achieve the "no smoke, no fire, no explosion" level, Lantu relies on three highlight technologies in battery safety: "three-dimensional insulation wall" technology; BMS battery safety monitoring and early warning model; high-safety battery PACK solution. 

Three-dimensional insulation wall

The three-dimensional heat insulation wall is not really a wall, but a set of defense mechanisms against heat diffusion of the battery cell. In the safety protection of ternary lithium batteries, thermal runaway of the battery cell is the object of protection. The protection mechanism is not to prevent thermal runaway of the battery cell, which is the task of the battery management system. The protection mechanism is to prevent the heat of the runaway battery cell from spreading after thermal runaway occurs, which in turn causes a thermal safety incident of the entire battery pack, so heat insulation has become the most important research and development direction.

This is a schematic diagram of the structure of the "three-dimensional insulation wall" of the Lantu FREE battery. Super-strong polymer insulation and flame-retardant materials are used between the battery cells to achieve a separate, all-round three-dimensional wrapping of each battery cell, forming an efficient insulation and flame-retardant protective layer. Each battery cell is fully wrapped in insulation and flame-retardant materials, shaped like "amber". Well, here is the most famous picture of amber. Let's feel it. The battery cell is tightly wrapped like a mosquito containing dinosaur blood.

On the top of the battery cell, an additional 1000-degree heat-resistant thermal insulation and flame-retardant layer is arranged. Even under the most extreme conditions, it can block the conduction of heat to the passenger compartment and provide the strongest protection for the people in the car.

From the overall design of the "three-dimensional insulation wall", it is not difficult to see that the main research and development direction of the current ternary lithium battery in safety protection is the strong blocking of heat diffusion. No matter what method is used, blocking the heat diffusion of out-of-control cells is the bottom line of the existing ternary lithium battery safety protection. Only when this is achieved can it be qualified to be called the 2.0 version of ternary lithium battery protection technology.

BMS battery safety monitoring and early warning model

The above mentioned technology is about preventing heat diffusion. The BMS battery monitoring and early warning model mentioned now is the technology to prevent thermal runaway. The "three-dimensional insulation wall" is a passive defense, just like seat belts and airbags, while the BMS monitoring and early warning is an active protection, equivalent to automatic braking.

By uploading BMS data to the cloud, the cloud database is compared with the monitoring data to diagnose, warn and monitor the battery life. When the system finds abnormal battery monitoring data, it will push the cloud APP and the vehicle's early warning system to warn the user in advance. At the same time, the system uses a high-sensitivity temperature detection sensor to monitor the temperature of each battery in real time. With the help of an efficient liquid cooling system, the battery pack is always kept in a high-efficiency temperature range regardless of winter or summer.

High safety battery PACK solution

This is visible protection for battery safety, and it is also the part that is most likely to bring confidence to consumers. The battery pack of VOYAH FREE adopts the industry's top protection design, providing all-round and no-dead-angle protection for the battery from five aspects: body protection, high-strength frame, pressure transmission, deformation energy absorption and double battery insurance.

For the battery pack, the biggest challenge comes from side collision, because such collision can easily lead to extrusion and deformation, and then induce thermal runaway. In the C-NCAP vehicle side impact test, the Lantu FREE battery pack with five-layer protection was subjected to the pole collision test at a European standard 75° oblique angle and 32km/h. The crossbeam only collapsed to a small extent, and the battery module was not squeezed or deformed at all.

Bang Reviews

Since the beginning of 2021, the safety protection technology of ternary lithium batteries has made a major breakthrough. If the previous ternary lithium battery protection was still at the level of single-cell protection, the safety protection technology of ternary lithium batteries launched this year, whether it is the magazine battery released by GAC Aion not long ago, or the "no smoke, no fire, no explosion" battery of Lantu FREE this time, has been upgraded from single-cell to system in terms of safety protection. The bottom-line protection capability of super-strong heat insulation blocks heat diffusion, cloud-based monitoring technology prevents thermal runaway, and ultra-high-strength shell provides passive protection. Systematic protection has become a powerful weapon for ternary lithium batteries to fight safety threats. The safer ternary lithium will surely become a new choice for OEMs.