BYD’s overarching corporate goal is to spur the mass-market adoption of green technologies and drive dramatic global economic and environmental recovery. BYD believes that we are in a unique position to do this as we have developed the industry’s only environmentally friendly battery chemistry: BYD “Iron-Phosphate” Battery (hereafter, Fe Battery). This battery technology has been a facilitator for two major technological breakthroughs within the global push to eliminate the dependence on heavy pollution emitting fossil fuels. (1) It enables renewable power generation to be relevant for grid operations with firm “dispatch-able” capacity. (2) It enables the introduction of long-range, long-service life, and fast charging capable electric vehicles. Utilizing BYD’s Fe Battery chemistry, we are capable of linking affordable solar/renewable energy power made relevant with environmentally friendly battery storage that is delivered responsibly to transportation—this in essence has completed the true ZERO Emissions Ecosystem.
BYD’s battery electric trucks utilize the same environmentally friendly Fe Battery that is supplied within our large scale fixed Energy Storage Stations (ESS). 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.
In comparison to traditional diesel engines or CNG powered heavy-duty vehicles, BYD’s all electric heavy-duty vehicles offer both qualitative and quantitative benefits that will have short- and long-term impacts on both a micro-level fleet operation and the macro-level environment.
On the micro-level, BYD’s Battery Electric trucks will cut operating costs by over 30% in comparison to utilizing an equivalent diesel or CNG vehicle. This added influx of overhead capital to a transit agency will produce an immediate impact on the community in terms of job growth, which will in turn lead to a downstream economic growth in the same community.
Furthermore, when BYD produces our Fe Battery, we consider the Total Life Cycle of each cell. Unlike other electric truck manufacturers that provide a single use of their batteries, BYD is in a unique position, because of our vertical integration, to repurpose batteries from our heavy duty vehicles (once they reach their useful life cycle) into our own Energy Storage Systems. We are our own customer for repurposing as well as recertifying packs and modules.
Battery Design
BYD internally developed the Fe Battery chemistry to ensure the stability and safety of each of our electric vehicles. BYD calls our batteries “Iron-Phosphate” versus “Lithium-Iron-Phosphate” because the dominant materials within the chemistry are Iron and Phosphate with only trace amounts of lithium varnished on the cathode/anode and in the salts of electrolyte.
The BYD Iron-Phosphate has achieved an industry benchmark in cycle life because it has overcome some of the most common failure-modes. In many Li-Ion batteries, when the cell charges and discharges anode undergoing oxidation and the cathode experiencing reduction, there is a net-net volume gain, causing increased pressures to build up in the cell layers as the cell is cycled. Eventually the layers “swell” so much and the pressure at the separator is so extreme that the electrolyte is pushed out of the gaps and electrolyte starvation occurs. This phenomenon immediately reduces the recoverable capacity of the cell and it dies very quickly. Because BYD’s Iron-Phosphate has the same crystal lattice between LiFe1-xCOxPO4 and Fe1-xCOxPO4, there is only a minute volume change (from m0.2914 nm3→0.2724 nm3). In fact, the oxidation capability of Fe1-xCoxPO4 is low enough that it results in no net-net volume gain during cycling. Therefore, the degradation curves shown in a normal cycle life format are very straight and predictable. There is no other chemistry that does this. All others show a rapid drop-off or “knee” on the curve when nearing the end-of-life at about 80% of the original capacity.
Battery Cycle Life
BYD has continuously been cycling our very large individual modules (multiple cells in each) for many years. After 9,500 cycles, the battery capacity still 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.
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.
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.
BYD’s Iron-Phosphate batteries contain no toxic electrolytes, no heavy metals in either the cathode or the anode. They are not manufactured with any caustic or harmful materials. This is the world’s first environmentally-friendly, high-energy density, and rechargeable chemistry! BYD electric vehicles are always outfitted with LED lighting, the highest efficiency lighting available.
