-  Image Courtesy of Alexander Trinh

Image Courtesy of Alexander Trinh

With experience fueled by innovation, BYD heavy-duty electric vehicles are purpose-built and hard at work exemplifying the endurance and reliability of its iron-phosphate batteries. Uniquely positioned as the industry’s only environmentally-friendly battery chemistry, BYD hopes to encourage the mass-market adoption of green technology to achieve its environmental goal of cooling the earth by 1°C.

Battery Safety

BYD Iron-Phosphate Batteries are designed and manufactured to provide safe, consistent, and reliable energy during rigorous and demanding applications. With safety as a priority and a core strength of its products, BYD internally developed the Fe Battery chemistry to ensure the stability of each of its electric vehicles. With millions of on-road miles and over 25 years of R&D and manufacturing experience, BYD batteries are built to last.

BYD’s revolutionary Iron-Phosphate Batteries are completely non-toxic with no thermal runaway events, even in the most extreme conditions. BYD confirms electrode structures according to many experiential models, such as current distribution models, thermal models, electrochemical models and mechanics models, to reduce resistance and optimize the current distribution and thermal distribution in the cell. Good thermal performance for high-power cells requires substantial thermal conduction paths, and can ensure the long-term stability and safety of a cell. BYD uses thermal imaging to confirm best-in-class thermal balancing inside a cell.

Multiple tests have been conducted to the BYD battery modules and packs to ensure safety. Some of these include: Vibration/Shaker Table Testing, Thermal Shock Test, Salt Spray Test, Crush Testing, Short Circuit Testing, Collision Test, Short Current Test, One-Hour Fire Simulation Test, and Gas Flaming Test.

Battery Design

BYD developed its Fe Battery Chemistry to be free of heavy metals and toxic electrolytes while possessing the smallest environmental impact of any electric vehicle battery system in the market today. The batteries are multi-purpose, initially powering battery-electric vehicles and then used on energy storage systems. BYD’s battery electric trucks utilize the same environmentally friendly Fe Battery technology that is supplied within its large scale fixed Energy Storage Stations (ESS).

The batteries do not contain any toxic electrolytes or heavy metals in either the cathode or the anode. They are not manufactured with any caustic or harmful materials, resulting in the world’s first environmentally-friendly, high-energy density, and rechargeable chemistry. BYD’s Fe Battery cathode is the safest cathode material because there is no thermal run-away mechanism or oxygen generated when decomposing. It also is the most robust when cycled because there is no net-net volume gain causing premature cell swelling or impedance growth. The Fe Battery packs not only meet all of the U.S. regulations, but also surpass the stringent U.S. DOT and FMVSS vehicle standards.

BYD battery packs use the most reliable welding methods available for assembling battery cells within a module. BYD uses both laser and ultrasonic welding to ensure that each battery assembly is not only reliable but also provides the most efficient thermal distribution.

Battery Cycle Life

When BYD produces its Fe Battery, the Total Life Cycle of each cell is always considered. Unlike other electric truck manufacturers that provide a single use of their batteries, BYD is in a unique position, because of its vertical integration, to repurpose the batteries and put them into their own Energy Storage Systems once they reach their useful life cycle.

BYD has continuously cycled its very large individual modules (multiple cells in each) for many years. Whole vehicle packs (with multiple modules) have been tested under continuous load, raising the surface temperature of the modules to about 40C. However, even under these harsh conditions, the capacity has remained at over 85% after 2,000 cycles, and over 75% after 4,000 cycles. After 9,500 cycles, the battery capacity remains at over 70.7% and the degradation curve is much more stable than any competitor’s modules.

This data was collected on a series of many modules all performing similarly – 6 cycles of charging and discharging were completed daily and this 9,500-cycle test has currently taken 5 years to get the data shown below. BYD have shown that these achieve well over 10,000 cycles, and the cell capacities can still reach 70% of the initial capacity. 10,000 single cell cycle testing includes six cycles each day.