- What are the advantages of LFP?
- Any downsides to LFP batteries?
- So what’s special about the Blade battery?
At this point, you’ve probably heard or read about the EV that’s about to be launched soon. It uses the company’s proprietary Blade battery, so what is it and what’s the difference from others?
First up, let’s talk briefly about its chemistry. The Blade battery uses lithium iron phosphate (LFP) as the cathode material. LFP battery is a type of lithium-ion battery that’s currently not as widely used in EVs as ternary lithium batteries with nickel manganese cobalt (NMC) oxide or nickel cobalt aluminium (NCA) oxide.
What are the advantages of LFP?
One of the main advantages is safety. Unlike NMC cells that release oxygen in the event of a thermal runaway (overheating of the battery, usually caused by damage like an accident), which catches fire easily, LFP cells hinder the release oxygen due to the phosphorus-oxygen bond in the cathode. In theory, at least.
BYD says that the Blade Battery emitted neither smoke nor fire after being penetrated, and its surface temperature only reached 30- to 60-degree Celsius. Under the same conditions, a ternary lithium battery would have exceeded 500-degree Celsius and burned.
Another advantage is lower cost. Nickel and cobalt are expensive to source and extract, while iron and phosphates are earth-abundant materials that are more easily accessible, which means lower cost.
Last but certainly not least, LFP batteries have greater cycle life compared to other lithium-ion batteries. Studies have found that LFP batteries have an estimated 3,000 life cycles at 100 percent depth of discharge (DoD), which means full depletion to fully charged, while NMC batteries degrade twice as quickly.
This is due to the aforementioned phosphorus-oxygen bond that makes it more stable to be stored at full charge. It also means that LFP batteries can be charged to 100 percent state of charge (SoC) with less concern of battery degradation. That being said, it’s still a good practice to avoid extreme ends of SoC.
Any downsides to LFP batteries?
Yes, the reason nickel is used in ternary lithium batteries is to increase the energy density. Without it in LFP batteries, the energy density is lower which, in the case of EVs, mean shorter driving range. To achieve the same driving range as NMC batteries for example, the battery pack will have to be larger.
So what’s special about the Blade battery?
Here’s where the Blade battery comes into play. The Blade battery cells allows for a cell-to-pack design that eliminates the need for modules. Regular block type prismatic cell has to be stacked in a module that takes up more space.
Without modules, the singular cells are arranged together in an array and then inserted into a battery pack. Due to its optimized battery pack structure, BYD says that space utilisation is increased by over 50 percent compared to conventional LFP block batteries, increasing overall volumetric energy density.
This cell-to-pack method is similar to what BMW is for their sixth-generation electric drivetrain.
Conclusion
BYD’s Blade battery uses LFP chemistry that is theoretically safer, costs less, and have a longer cycle life. Its downside is the lower energy density compared to ternary lithium batteries. However, the Blade battery design mitigates the disadvantage with its clever form factor, allowing a higher energy density at the pack level.
The BYD Atto 3 is scheduled to be launched in Malaysia tomorrow (8-December 2022), stay tuned to WapCar.my for the latest updates.
Keyword: BYD Atto 3's LFP Blade battery - This is what makes it superior to its rivals