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Battery Ownership

The high cost of lithium-ion (Li-ion) batteries may be the largest impediment to more widespread adoption of electric vehicles (EVs). NREL is exploring ways to reduce EV ownership expenses and improve vehicle utility, including battery swapping, charge-point service contracts (including fast charging), and vehicle-to-grid revenue generation strategies.

Calculating the true cost of EVs is complicated by proposed business models, as well as by fluctuating battery degradation rates, driving patterns, charging strategies, government incentives, and other factors. NREL's Battery Ownership Model (BOM) takes the guesswork out of determining EV cost and comparing it to that of conventional vehicles.

The BOM model can be used on its own to evaluate lifetime battery costs and to conduct simple analysis of performance factors, or be paired with the Battery Lifetime Analysis and Simulation Tool for Vehicles (BLAST-V) for highly realistic long-term technical comparisons of different battery use strategies. When BLAST and BOM are used together, the detailed techno-economic simulations factor in the value of the entire vehicle and life cycle to accurately predict total EV purchase and operation expenses and identify cost-effective use strategies.

Exploring Economics of Operating Electric Vehicles

Bar graph providing a conceptual overview of BOM calculation outputs. Y-axis shows 75th percentile PHEV to CV (conventional vehicle) cost ratio (ranging from 0.7 to 1.1) and the x-axis represents 12 different undefined charging strategies (CS). Twelve sets of vertical bars show the projected costs relative to four different states of charge (SOC): 85%, 90%, 95%, and 100%. The cost ratio patterns vary, with cost ratios ranging from a low of approximately 0.85 for a scenario labeled PHEV25, CS3 at a 100% SOC, to a high of approximately 0.97 for scenarios labeled PHEV45, CS1 and CS2 at an 85% SOC.

BOM calculations have shown that PHEVs can be more cost-effective than conventionally powered vehicles (CVs) under numerous combinations of electric range, charging strategies (CS), battery cost, and other parameters. SOC = state of charge.

The BOM combines EV battery use simulation with detailed economic accounting functions to quantify total lifetime costs of EV operation. It considers the effect of battery cost, wear, and replacement; drive cycles; location-specific gas and electricity prices; component costs; and greenhouse gas emissions.

BOM analyses applied to studies of battery-powered electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) have shown that driving patterns can have a greater impact on EV economics than charging strategies or driving range, confirming how important it is to factor real-world, driver-specific travel patterns into economic analyses. BOM tools and methods have also been instrumental in technical analysis supporting identification of DOE and U.S. Advanced Battery Consortium (USABC) technical targets for BEVs.

Analyzing Third-Party Service Providers

Two bar graphs providing conceptual overviews of BOM calculation outputs. In both graphs, the y-axis shows monthly service fees ranging from $0 to $700 and the x-axis represents batteries at three different cost levels ($125/kWh, $300/kWh, $475/kWh) used in BEVs with ranges of 50 (BEV50), 75 (BEV75), and 100 (BEV100) miles. In each graph, three sets of vertical bars show the projected service fees related to G&A, private charging, electricity, battery purchase, and battery swapping for vehicles at each of these ranges and battery costs. The top graph represents high service business strategies. Here, service fees for battery swapping decrease as vehicle range increases, with totals of approximately $300 per month for the BEV50 and totals of approximately $150 per month for the BEV100 at all three battery costs. The fees for G&A (approximately $10) and private chargers (approximately $50) are identical across scenarios. Battery-related service fees increase incrementally with increase in vehicle range and battery cost, from a low of approximately $50 per month for the BEV50 with $125/kWh batteries, to a high of approximately $400 per month for the BEV100 with $475/kWh batteries. The bottom graph represents low service business strategies. Here, service fees increase in steady progression with battery costs, with totals of approximately $190 per month for the BEV50 with $125/kWh batteries at the low end of the range, and totals of approximately $500 per month for the BEV100 with $475/kWh batteries at the high end of the range.

Studies of battery swapping service provider economics have quantified the monthly service fee and relative cost of batteries, infrastructure, and other factors for high (top) and low (bottom) service business strategies.

The BOM is the only tool of its kind that can be used to evaluate third-party service providers, including public charging network operators or battery leasing companies. The BOM can account for costs such as infrastructure and battery wear and replacement, and translate these expenses into a service fee charged to drivers. These capabilities have been employed to evaluate the economics of third-party battery swapping strategies, as well as combined battery leasing and fast charger access.

Publications

Learn more about NREL's battery ownership modeling in these publications.

Contact

For more information on NREL's battery ownership activities, contact Eric Wood, 303-275-3290.