We estimate the copper weight of the HV harness to range between 4.5 kg and 6.0 kg. In total, we forecast that the HV wire harness market in alternative vehicles will increase from 5 kt of copper in 2010 to 92 kt in 2020. The figures for Europe are virtually zero and 17 kt of copper. The main product group is insulated wire, although strip and other products used in connectors is also important.
Batteries
Battery technology has been a limiting factor in the progress of hybrid and electric vehicles to date, both on capacity and cost grounds. The technology of energy storage is developing rapidly, with the lithium-ion battery coming out as a clear winner for a wide range of applications, including electric vehicles. While not a particularly copper intensive battery solution, there is copper in this market. An analysis of batteries in the automotive sector in the wider context of energy storage is provided in Section 6 “Cross Market Technologies”.
The key requirements for hybrid batteries today are a voltage range from 200 to 300 volts, the ability to absorb high quantities of electricity in short periods, low weight, durability, energetic efficiency and cost. To some extent the requirements are negatively correlated, leading to the need to compromise. For example, high capacity requirements are associated with increased size, weight and cost.
There are technical approaches for every one of the criterions; however maximising all of them at the same time is not feasible due to a negative correlation of some of the objectives. This makes it necessary to increase the battery size and hence its weight accordingly or to accept a shorter operating distance. Fast charging is associated with heat generation and loss of efficiency.
To some degree, these contradictions are being overcome through technology development. Energy density to weight ratios for lithium-ion batteries are being improved substantially, thus extending the range of vehicles operating in charge depletion mode.
The cost of batteries is also on the way down, but is still very high. The current industry-wide average production cost of lithium-ion batteries is US$600 per kWh, with a number of individual companies achieving lower costs. For a pure electric vehicle with a 30 kWh battery, therefore, today’s battery costs equate to US$18,000. For a PHEV with a 16 kWh battery, the incremental battery cost is US$9,600.
Such high costs mean that without financial incentives, the additional capital cost of hybrids and BEVs is substantially above the energy cost saving that could be achieved over the lifetime of a vehicle. Reducing battery prices and increased energy cost saving over the next decade should ensure a cross over where the alternative vehicles become truly economic to the consumer in the latter part of the next decade.
Most of the present fleet of HEVs is fitted with Ni-MH batteries. In 2009, Toyota has substituted the Ni-MH battery with Li-Ion in the new plug-in Prius for on-road trials. Other manufacturers are already focussing on li-ion technology, and the Ni-MH alternative is expected to be phased out quite quickly.
This represents a significant step for bringing lithium-ion on the road to mass deployment. Manufacturers around the world have invested in developing different type of battery technologies in order to overcome the existing problems of capacity, storage and price. Lithium-ion batteries are attractive because they deliver superior performance in both power and energy density, allowing them to achieve a much higher weight to performance ratio than either of their predecessors. Lithium-ion battery chemistries can achieve theoretical energy densities up to 175 WH/kg and power densities up to 9,000 WH/kg.
Figure 32: Materials Content of Li Batteries6
A primary use of copper in li-ion batteries is to coat the graphite anode. The anode is typically coated with aluminium. For this, copper foil of 14 μm thickness (uncoated) is generally used, although coated materials of up to 200 μm thickness can be employed, depending on the cell design (cylindrical or planar. Most copper foil is electrodeposited, Furukawa Electric being a dominant supplier. For smaller li-ion batteries, however, Hitachi Cable has announced a newly developed rolled foil product, said to enhance battery life. This product is an adaptation of Hitachi Cable’s HCL02Z alloy, containing zirconium at 0.02%.
In volume terms, more important are the current carrying elements within the battery and external buss bars that must be joined to the outside terminals to connect a series of cells. A combination of copper and aluminium is used for this purpose.
The amount of copper contained in li-ion batteries is open to question, and appears to be variable. One estimate has copper constituting 17-20% of lithium-ion weight. Our, more modest, estimate puts the copper in HV automotive battery market at around 1 kt in 2010 rising to 21 kt in 2010. The European market is forecast to rise from virtually zero to 4.1 kt of copper in 2020. Around 40% of this market is expected to be copper foil, the remainder being other mill products.
Charging Infrastructure
Alongside PHEVs and BEVs there will be a requirement for an electricity charging infrastructure. Some charging will be in the home, but there will also be a need for an infrastructure outside the home, especially for BEVs that have no alternative means of propulsion. For the apartment-dwelling section of the alternative vehicle community, street charging will be a necessity from the outset.
The number of charging points in relation to the number of PHEVs and BEVs will be large, especially in the early stages of development. Assuming the vehicle owner has an access point in his dwelling, there will be one charging point for each vehicle captive to that owner. It is estimated that, in the early stages there could be as many as 2.5 public charging points per vehicle, falling ultimately to 0.5 points or less. However one looks at it, this will require a massive investment, and a considerable amount of copper.
Figure 33: Home Charging Infrastructure7
The home charging point runs is connected to a circuit breaker to the charging unit itself, from which a flexible cord and connector leads to the vehicle. The sophistication of the charging unit should increase over time to accommodate smart metering and variable electricity tariff arrangements, and ultimately electricity resale.
The cost and size of the unit will also depend on the rate of charging required. Without any enhancement, it may take 15 hours to charge a PHEV battery, based on the United States 100 volt infrastructure. Upgrading this to a 220 volt 15 AMP connection would reduce the charging time for a 24 kWh battery to 8 hours; a 30 AMP connection would halve this. The cost of such enhanced connections is around US$500-1,000 currently.
The public infrastructure will contain many similar level connections. Such units are likely to be provided in many cases in banks of chargers, with a cable running back to the final distribution transformer. While such charging points may make sense at places of work, where the car owners will stay for hours, however, there is also a need for very fast charging, with 30-250 kWh capacity. This may allow, for example, a car to be charged while the occupant was shopping.
Taking the above into account, we foresee the average consumption of copper in charging infrastructure per PHEV or BEV starting at around 7 kg in 2010, falling to around 1 kg by 2020. This implies a global market rising from virtually zero in 2010 to 10.6 kt of copper in 2020. The European market, with higher electric vehicle sales than output, is forecast to rise to 4.1 kt of copper. The main product will be energy cable, with winding wire also being important.
Perhaps more important than the new charging infrastructure itself will be the need to upgrade distribution transformers in the grid. The rate of charging on a 220V 15 AMP system could be around 3.3 kWh, a little less than the electricity consumption of the average US home. A 30 AMP system would absorb double this amount. Although most charging is expected to be at night, this could lead to an unsustainable strain on the existing electricity infrastructure. A recent EPRI study showed that plugging in just one PHEV in the day time in residential neighbourhoods led to the failure of 36 of 53 transformers. Perhaps more surprising, the same experiment at night led to the failure of 5 of the 53 transformers.
Just how many transformers will need to be replaced (or how many added) as a direct result of PHEV and BEV use is open to question. Where the final distribution transformers are copper, however, this could be a substantial market.
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