Volkswagen Group talks EV charging standards, electrification strategy

One of approximately twenty VW Golf blue e-motion prototypes under test in the United States, with Eaton’s 50kW DC Quick Charger, at Volkswagen’s Electronics Research Laboratory, near San Francisco. Click to enlarge.

Earlier this month, Volkswagen and Eaton executives met with a small group of journalists at the VW Electronics Research Laboratory in Belmont, California, to discuss VW’s partnership with Eaton on AC and DC charging, followed by a broader conversation about VW’s plans for vehicle electrification over the next several years. Topics included the upcoming introduction of the blue e-motion Golf electric vehicle, sometimes called the e-Golf, near the end of 2013 (early 2014 for the US market), as well as Volkswagen’s goal of achieving 3% of its global sales through plug-in vehicles by 2018.

That goal is part of VW’s overarching Strategie 18, in which the Wolfsburg-based manufacturer hopes to trump Toyota in global sales by the same year. Volkswagen sold 9.07 million vehicles in 2012 to Toyota’s 9.7 million; assuming 10 million vehicles sold per year in 2018, VW would need to move 300,000 plug-in vehicles per year to meet their mark.

Plug-in Charging. The gathering marked the introduction of Eaton’s DC quick charger (link), one of which is now installed at ERL. The charger has a maximum output of 50 kW, and is constructed using 10 kW modules, or “power drawers”, to allow for expansion: for example, a customer can specify a 20 kW charger, and scale up later to 30, 40, or 50kW as needed.

Although the Eaton charger at ERL is equipped with the new SAE J1772 Combined Charging System (CCS) for AC or DC charging (earlier post), and Volkswagen supports the new standard, both Eaton and VW said that they will support CHAdeMO if that standard prevails, particularly in the Japanese market. Eaton’s John Wirtz confirmed “it would not be difficult” to equip their DC charger with charge connectors for either standard, or with charging cables for both standards, if desired.

Volkswagen’s Rudolf Krebs, who heads VW’s electric powertrain division, further explained that VW sees plug-in charging as evolving toward four levels:

1. single-phase AC;
2. fast three-phase AC (in Europe);
3. DC charging of up to 20kW; and
4. public DC charging of up to 86 kW.

Three-phase AC is readily available in many parts of Europe, and is used in those areas to power high-demand appliances. DC quick charging will be available for VW’s battery electric vehicles, but not for their plug-in hybrids: PHEV usage patterns, in the company’s opinion, renders DC charging “unnecessary”.

This sentiment echoes the position taken by General Motors; in a previous interview, GM’s Larry Nitz, Executive Director of Hybrid and Electric Powertrain Engineering, observed that around half of all Volt users use only Level 1 (110V AC, standard wall receptacle) charging equipment to charge their vehicles, eschewing Level 2 (240V AC) chargers altogether.

Volkswagen also expects plug-in hybrids to coalesce around an all-electric range of 35 miles in the United States, as well as a slightly shorter 50 km (31 miles) range in other markets, spurred by governmental policies, including expected policy in China.

Which charging standard will prevail?
“DC charging” refers to a charging protocol in which a charging station supplies direct current to a plug-in vehicle’s battery pack. This type of charging, which can be used to “quick charge” some compatible battery packs to 80% state-of-charge (SOC) in as little as ten to twenty minutes, contrasts with the much more common AC charging protocols, in which alternating charging current is supplied to the vehicle and is rectified to direct current by the vehicle’s on-board charger component, which then charges the battery pack.
Efforts to find consensus on a single charging standard have so far been elusive, particularly with respect to DC charging. Although the CHAdeMO DC charging standard prevails in Japan, with almost 1400 such chargers installed in that country, it is not integrated with AC charging. A CHAdeMO-complaint vehicle therefore requires a large charging door (e.g., Nissan LEAF) or two separate charging doors (e.g., Mitsubishi i-MiEV).
Volkswagen executives indicated that they had met with CHAdeMO representatives in the past to discuss a single charging standard, but were unable to come to an agreement; one executive reminisced “that was a very difficult discussion” which “quickly became political”. Although many manufacturers of plug-in vehicles, including Volkswagen, support the SAE J1772 AC-DC “combo connector” standard in the US market, as well as the somewhat similar VDE-AR-E 2623-2-2 AC-DC standard in Europe, one VW executive remarked “we don’t want to discriminate” on charging standards, explaining “...the investors and the users will decide”.

Battery Development. In the absence of revolutionary breakthroughs, Krebs expects current lithium-ion battery technology to achieve “perhaps a doubling of capacity” through an “evolutionary” process over time. With regard to battery pack cost reduction, he cited an ongoing partnership with Johnson Controls-owned Varta on battery cost, explaining “we do not understand the cost level today”, and that there appears to be a disconnect between cell costs in the consumer electronics sector as compared to the automotive sector.

Asked about the prospect of bringing cell production in-house to reduce costs, Krebs cautioned “I would not recommend that. We [the global lithium-ion industry] have overcapacity right now, and companies that are putting billions of dollars into [battery] research.”

Commodity cells, which are small mass-produced cells constructed to standardized sizes, such as 18650 (18mm diameter x 65mm length) cells, were also dismissed as impractical, due to the number of cells and connections required in a pack, as well as the amount of space taken up by cell packaging. The Tesla roadster is perhaps the best known example of a plug-in vehicle powered by commodity cells, with some 6800 separate cells making up the vehicle’s battery pack.

Electrification Strategy. Observing that a 90% reduction of greenhouse gas (GHG) emissions by 2050 would require Volkswagen to reduce CO₂ emissions to twenty grams per vehicle, Krebs remarked “…this gap can only be closed with electrification.” However, Volkswagen’s internal well-to-wheel data suggests that electric vehicles can enable GHG reductions over current diesel-powered vehicles only in regions with relatively clean power generation profiles.

Noting that China is considering new policies to spur domestic plug-in vehicle production and sales, with a target of 500,000 plug-in vehicles by 2015, Krebs opined “in terms of CO₂ and climate change, this will not help.”

Comparison of well-to-wheel CO2emissions associated with the operation of Volkswagen’s TDI BlueMotion Golf diesel sedan, as well as the blue e-motion Golf EV, with various power generation sources shown for the latter vehicle. Adapted from Volkswagen’s graph. Click to enlarge.

Quizzed on the feasibility of diesel hybrids, Krebs was somewhat bearish: “To be honest, the cost of a diesel [engine] is extremely high, especially with the upcoming emissions technology. In terms of cost it is not so viable, and a diesel engine is already so efficient.”

However, Volkswagen and Audi have both shown plug-in hybrid diesel concept vehicles in the past, with VW debuting two such concepts—the CrossBlue crossover vehicle and the Cross Coupé compact SUV—at the Detroit Auto Show last week. Volkswagen estimates the production cost of a plug-in hybrid or electric vehicle’s powertrain to be about five times the cost of a conventional powertrain. Such costs can be mitigated to some extent through integration, but “that will take about ten years”.

How many plug-in vehicles can Volkswagen sell? “We really do not know, but we see more and more people willing to switch over, more people trusting the technology. It will not be a mass market at first, but we have so many cars already. We need to make electromobility fascinating.” Krebs has used an e-Golf for about a year, and is comfortable using it within a range of about 50 km from his house, with the exception of the autobahn, where he finds that the vehicle’s range can be cut in half, “even at moderate speeds”.

Given the present range limitations, VW expects battery electric vehicles to be used as second or third household vehicles or as light transport and delivery vehicles, in addition to a small early adopter market.

Provisional schedule of hybrid, plug-in hybrid, and electric vehicles within Volkswagen Group. Click to enlarge.

On a personal note, Krebs expressed his own surprise upon joining the converts, remarking: “I am a combustion engineer by heritage, but I like going electric. At the end of the day, the consumers and the OEMs will decide.”

Volkswagen’s Electronics Research Laboratory began operations in 1998 with three employees. VW ERL now has about 100 employees, and ERL alumni work at Volkswagen Group offices worldwide. Current ERL research subjects include advanced driver assistance functions, sensor concepts, image processing, autonomous driving, haptics, voice user interfaces, networked speech recognition, social networking and geotagged information, and connected eco-driving. ERL teams also test and validate navigation and connectivity systems.

VW’s ERL collaborates with academia on projects such as the Intelligent Urban Mobility initiative (with UC San Diego, University of Southern California, UC Berkeley PATH, and the University of Michigan Transportation Research Institute) and the Volkswagen Automotive Innovation Laboratory (with Stanford University’s School of Engineering).

Source: Green Car Congress