Text/Qin Ming
Technology update iteration, product survival of the fittest, new energy vehicles stand at the forefront of the times and fuel vehicle competition in the future protagonist, electric vehicles want to surpass fuel vehicles, endurance becomes the key, batteries are the direct influence of battery life, the electric vehicle battery on the market is nothing more than lithium iron phosphate battery and ternary lithium battery, these two batteries have their own advantages and disadvantages, the contest in the market is also one after the other, there are back and forth.
Now lithium iron phosphate batteries rely on blade batteries to gain the upper hand, many car manufacturers will turn their attention to lithium iron phosphate batteries, BYD also with blade batteries to become the pure electricity market of the fragrant food, then what is the blade battery, there is such a big role in subverting the status of enterprises and industry direction, we will open the blade battery "shell", to find out.
Construct parsing
Blade battery many people think that it is a new battery technology, which is essentially a lithium iron phosphate battery, but the traditional cylindrical shape of the single battery, changed to a long and thin blade-like single battery, so it is taken as a blade battery.
Compared with traditional single cylindrical batteries, which accumulate too many inter-cell gaps, flat blade batteries can make full use of the space inside the battery assembly, and the benefits are obvious, more individual blade batteries can be placed, resulting in increased battery energy density per unit volume.
Blade battery is a kind of lithium iron phosphate battery structure innovation, the use of Ningde CTP moduleless solution, due to the change in the structure of the battery cell, the design of the battery pack has also changed, the cancellation of the shell structure of the traditional battery, by the blade battery to act as a battery beam, but also as a battery cell. Then adopt the design of honeycomb aluminum plate, paste two high-strength aluminum plates on the upper and lower sides, and the blade batteries are arranged in it. In this way, the traditional module link is skipped, the space utilization rate is improved, and more batteries can be installed in the same space.
The battery cell adopts laminated structure + ceramic coating technology, which eliminates most of the space occupied by the cell shell and parts, for example, the lithium iron phosphate battery is equivalent to a battery pack made up of multiple batteries, and the blade battery is directly composed of a battery by the battery cell.
Small size, light weight, long endurance
The advantage of the blade battery comes from the innovative structure, the blade battery is small in size and light in weight, which can bring better space performance to the vehicle, while reducing its own resistance, reducing power consumption, and the cruising range will be further improved.
Blade battery volume utilization rate is higher, can accommodate more cells, volume energy density increased, cruising range has also been greatly improved, has reached the same energy level as ternary lithium battery, BYD pure electric model endurance pure electric mileage has come to 605km, enough to prove the high endurance of blade batteries.
Safer after battery failure
While bringing about an increase in battery energy, it retains the advantages of high temperature resistance of lithium iron phosphate batteries and has a high degree of safety.
BYD compares the blade battery with the ternary lithium battery and the lithium iron phosphate battery for acupuncture experiments, the experimental process is to use a high-temperature steel needle with a diameter of 5-8mm, vertically through the fully charged battery, and then observe the various indicators of the battery. Ternary lithium battery in the needle punching moment, the battery pack inside the violent combustion, the temperature climbed to 500 ° C, accompanied by open flame and smoke phenomenon, lithium iron phosphate battery in the needle punch instantaneous smoke phenomenon, up to 200-400 ° C, and blade battery acupuncture experiment, did not occur violent reaction, the temperature is only 30 ° C -60 ° C.
The purpose of the acupuncture experiment is to make a short circuit inside the battery and then observe the thermal safety of the battery. However, I think that the acupuncture experiment can not fully explain the safety of the blade battery, it is true that there is not much reaction in terms of thermal runaway, do not worry about the spontaneous combustion of ternary lithium batteries, but it does not prove that the probability of thermal runaway of the blade battery is small, and once the battery is thermally out of control, it is still necessary to throw you halfway.
Whether battery safety should start from the essence of the problem, rather than the treatment of the problem after the problem, although the severity of the situation is different, but there is still an accident.
There is not much improvement in performance at low temperatures
Blade battery is after all a lithium iron phosphate battery, naturally will inherit some of the shortcomings of lithium iron phosphate battery, we all know that lithium iron phosphate battery in the low temperature state, performance performance is greatly reduced, at -20 ° C, lithium iron phosphate battery is only 80%, although BYD in the blade battery using a thermal management system, can make the battery internal temperature control at an optimal working temperature, but also only to a certain extent to alleviate the impact of low temperature on the battery, and there will be no qualitative leap, which is not very friendly to northern users, And the battery attenuation in winter is also the same as that of lithium iron phosphate batteries, and the service life is not as good as that of ternary lithium batteries in winter.
Battery repair is equivalent to replacement
And because the blade battery is also a CTP scheme, its battery pack is composed of cells, which are not directly placed in the battery pack, but are installed by various connectors and fixed by special glue. This glue used to fix the battery cell can firmly fix the battery cell in the battery pack, while playing a certain thermal conductivity, flame retardant and buffering effect, but on the contrary, the battery cell is stuck together after it is difficult to disassemble.
It means that in the later stage, a battery is broken or it is difficult to repair if it is hit, and the only feasible maintenance method is to destroy the strength of the glue through ultra-low temperature, and then remove the damaged blade battery from the battery pack, but the maintenance technology is still very difficult to achieve, the environmental requirements are high, the cost is high, and it is difficult to apply on a large scale for the time being.
Only by improving the consistency of the battery cell as much as possible, reducing the failure probability of a single cell to reduce the maintenance needs of the battery pack, or directly replace the entire battery pack, and the traditional modular battery pack, you can replace the single module to repair, so that the cost of blade battery maintenance will be very high.
Write at the end:
Blade batteries have advantages and disadvantages, not so godly network uploads, but also has the inherent disadvantages of lithium iron phosphate, but overall, both the long endurance of ternary lithium and lithium iron phosphate safe high temperature resistance, advantages outweigh the disadvantages, BYD pure electric models can be favored in the market there are also blade batteries a lot of credit.