What is Blade Battery?

The lithium-ion batteries of electric vehicles on the market are mainly equipped with lithium iron phosphate batteries and ternary lithium batteries. There are significant differences between the two batteries in their own characteristics.

Compared with ternary batteries, lithium iron phosphate batteries have lower cost and long cycle life. Most importantly, the thermal stability of lithium iron phosphate batteries is currently the best among lithium-ion batteries for commercial applications. They are usually not prone to the risk of fire and explosion, so they have always been the main choice for commercial vehicles such as electric buses. However, its most important disadvantage is that the energy density of the monomer is low, resulting in a battery of the same weight, the range is much worse than that of a ternary lithium battery.

48V 135Ah Lithium Battery Pack

Compared with lithium iron phosphate batteries, most car companies currently use ternary lithium batteries, mainly because of the high energy density of ternary lithium batteries, which means that under the same quality, the range of ternary lithium batteries is longer than that of models using lithium iron phosphate batteries, and the low temperature performance is good. However, the disadvantages of ternary lithium batteries are poor thermal stability, high production technology threshold, and high raw material costs.

The following is a chart which directly illustrate differences in different kinds of power batteries. Of course, these battereis are not only lithium batteries such as Ternary battery and LiFePO4 battery, but also some other common batteries in market. According to this chart, we can simply see that LiFePO4 batteries are the best in comprehensive factors.

Simple Comparision among Power Battery
Ternary Battery LFP LMO LCO
Energy Density(Wh/kg) >180 200-280 120-190 130-150 150-180
Voltage(V) 3.7 3.6 3.2 3.8 3.7
Cycle life >2000 >2000 over 10000 500-800 >1000
cost High high low lowest A bit high
Material Resources Cobalt is rare Cobalt is rare Rich Resource Rich Resource Cobalt is rare
Temperature Range -30-65℃ -30-65℃ -20-70℃ -20-45℃ -20-80℃
advantage 1.High energy density
2.Good low temperature performance
1.stable electrical chemistry
2.Good cycle performance
1.Higher safety
2.Good cycle performance
2.low cost
1.stable charging and discharging
2.simple manufacturing process
Disadvantages 1. poor in safety
2. High manufacturing technology
3. High raw material price
1. Cobalt is expensive 1. poor in low temperature
2.Low discharge voltage
1. Poor in safety
2. Low energy density
3. Short battery life
1. cost high
2. Short cycle life
3. Poor in safety

What is Blade Battery?

As we all know, blade batteries are actually lithium iron phosphate batteries in essence, which can be regarded as a process of lithium iron phosphate. It still has the characteristics of high battery life of lithium iron phosphate batteries in winter. Because it looks like a blade, it is named the blade battery.

Blade battery of BYD was launched in 2020 and adopts high-safety lithium iron phosphate technology, which has a 50% increase in volume and energy density.The battery has passed the most demanding acupuncture test in the industry.Electric vehicles equipped with blade batteries can have a range of more than 600 kilometers.Compared with ordinary lithium iron phosphate and ternary batteries, blade batteries perform better in terms of safety, volume utilization, cycle life, and structural strength.

In fact, the blade battery is essentially a square hard shell battery, but it adopts a long and thin structure design. The overall dimensions are 960mm×90mm×13.5mm. Different models have slightly different sizes. For example, the thickness of the 138AH blade battery is about 12mm, while the thickness of the 202Ah blade battery is about 13.5mm. The pole terminals of the blade battery are threaded and welded platform type. When assembling the battery pack, the positive and negative poles between the batteries can be connected according to actual needs. These two connection methods.The negative side terminal is also provided with an explosive-proof valve.

The design of the lithium battery pack has also been changed by using the CTP module-free scheme to change cell structure. The shell structure of the traditional battery is cancelled, and the blade battery acts as the beam of the battery and also acts as the battery cell. Then the design of honeycomb aluminum plate is adopted, two high-strength aluminum plates are pasted on the upper and lower sides, and the blade batteries are arranged in them.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.

When assembling the battery pack, people use the strength of the blade battery itself, the battery pack is grouped to reduce the beam, etc. Under random vibration load, the deformation of the module form is large, and the deformation of the blade battery cell is small. People modular battery pack by changing the structure of the battery pack, the rectangular batteries are arranged vertically and inserted into the battery pack, the structure of the battery pack is simplified, and the space utilization rate in the bag is improved.

Advantages of  Blade Battery

  • Flexible structure: The blade battery has a flexible structure, and the length of each battery can be customized to make full use of the space in the car.Compared with ordinary lithium iron phosphate batteries, the volume utilization rate of blade batteries has increased by more than 50%, reaching the same level as ternary lithium batteries.

  • High strength: Just like one chopstick breaks when it is folded, and a brunch of chopsticks is difficult to break, hundreds of blade battery cells with a length of less than one meter are tightly arranged together, which are stronger and provide additional help to the safety structure of the vehicle in the event of a collision.

  • The range is close to ternary lithium: at the same volume or quality, the higher the power that the battery can store, then we say that its volumetric energy density or mass energy density is higher, then the battery life of new energy vehicles will be higher.The shortcomings of ordinary lithium iron phosphate in energy density are made up for by blade batteries

  • Longer battery life: We all know that to measure the quality of a battery, we must also look at the life of the battery, that is, the number of times the battery can be charged and discharged (the number of cycles). At present, lithium manganese acid batteries have the lowest number of cycles, ternary lithium batteries are the center, and lithium iron phosphate batteries have the highest number of cycles, as are blade batteries as lithium iron phosphate batteries.

  • Excellent safety performance: puncture test, the surface temperature of the blade battery is 30-60 degrees, and it is not easy to spontaneously ignite.

Disadvantages of Blade Battery

  • The battery characteristics are relatively poor at low temperatures, and it is still not resistant to low temperatures.This is an “occupational disease” of lithium iron phosphate, and the battery power will be greatly reduced in cold winter conditions.

  • The maintenance cost is higher because the blade battery eliminates the need for a structure to support the battery cells, and uses each battery cell itself as a bracket.Under the impact of external forces, it is difficult to ensure the integrity of the battery.One battery is damaged, and the rest of the batteries in series will also be affected.

  • The manufacturing cost and process difficulty are higher.

Great Technology of Blade Battery

  • The large-size laminating process lays the high-performance foundation for blade batteries

Traditional power batteries produce batteries in the form of winding, while blade batteries use a laminated process. Compared with the winding structure, the current density of the laminated structure is more uniform and consistent, and the internal heat dissipation performance is better, which is suitable for high-power charging and discharging. Therefore, the blade battery has better cycle characteristics and safety characteristics. For the shortcomings of lithium iron phosphate, the energy density is low.  The blade battery solves this problem according to the arrangement pattern, just like a box full of ping-pong balls. The density is very small, but if you change to a ruler, the density is very high, which improves the utilization rate of space.

  • Comprehensive high temperature ceramic battery technology

Ceramic coating can improve the performance and safety factor of lithium-ion batteries. This kind of safety coating can prevent severe reactions for a short period of time in the battery cell, greatly improve the safety factor and cycle life, and prevent the battery from using high-temperature and insulating high-temperature ceramic coatings in key parts.

Why is the blade battery life only 8 years?

The manufacturer did not say that the service life of the blade battery is “only 8 years”, but that the service life of the blade battery is “up to 8 years.  It seems that everyone can live to 75 years old or not live to 75 years old.  The official announcement is the theoretical data after the test, and the service life of the battery is gradually decreasing, unlike the shelf life of food, there is a limited expiration date.

How to understand the service life of the blade battery?

According to the data released by the manufacturer, it can be determined that the theoretical service life of the blade battery is 1.2 million kilometers in 8 years, and the charge and discharge cycle life is more than 3,000 times. Translated into vernacular, it is explained that “the theoretical service life of the blade battery is 1.2 million kilometers within 8 years, and it supports 3,000 charges and discharges.” In other words, if the car owner does not run full 120 kilometers in 8 years, then the battery can continue to be used, but the battery life and power storage capacity are not as strong as before.

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