02 A Brief History of Batteries
Around 1832 Robert Anderson[1] a Scot, developed the first crude electric carriage which used a non-rechargable battery. With the invention of the lead acid battery in 1859 by the French physicist Guston Plante, EVs gained ascendancy. It wasn't however until the 1870's onward that they became practical and even popular. By 1897[2] there was even a fleet of electric taxis[3] in London. One notable example was the fleet owned by Walter C. Bersey[4].
In order to understand the challenges facing battery development it is necessary to have a sense of how they work.
In an ideal electric car there would be a lot of electrical energy flowing to the engine for a very long time thus allowing it to go faster or pull heavier loads longer. The amount of electrical energy stored[5] in a battery of a certain mass or volume (X) is called its ‘Energy Density’ and is measured in Watts/Kg. The rate at which the battery can give off that energy is called its Power Density and is measured in Watt Hours/Kg. Unfortunately batteries have a high Energy Density meaning that they carry lots of energy but a low Power Density meaning that they lose that energy slowly. In order to get more electricity out of them you have to increase their size.
Capacitors in direct contrast, while similar in size to the (X) battery have a small Energy Density with a high Power Density. This means that they carry little energy and they lose it all quickly so in order to have a longer discharge rate their size needs to be increased.
The two components that disadvantaged the Electric Vehicles back in the late 19th century and again in the 21st century were firstly the achievable ‘range’ of the cars due to the Energy Density of the batteries and secondly their charging times.
A very efficient internal combustion engine, by comparison, has an approximate Energy Density of 12KWh/Kg[6] or liter of fuel whereas a 1Kg battery delivers around 120 to 210Wh/Kg. However EV engines run at 90% efficiency upward[7], while internal combustion engines lose about 60%[8] of their chemical potential energy in heat created just from the combustion. Add to that 60% the energy lost in an internal combustion car’s transmission and differential and we realize that the energy density gap between Internal Combustion and Electric Vehicles isn't that big after all.
A very good comparison in a YouTube video[9] made by Mr Jonathan Porterfield from eco-cars.net compares two same modeled vans. One is the “Nissan eNV200'' electric van and the other is the “Nissan NV200 Acenta 1.5DCi diesel van”. In the video he compares the cost of running, servicing and the degradation, if any, of the electric eNV200 which when the video was made had traveled a total of 100,300 Miles (161,417 Km) with a diesel Nissan NV200 that would have traveled 100,000 Miles (160,934 Km) over a 5 year period. As he quite thoroughly and fairly shows in the video, the running and maintenance cost of the diesel van (running time in video 2:28 to 5:57) comes out at £16,398 (€18,417). In the electric van the same running and maintenance cost while charging the van at a relatively average cost of £0.15/kWh (€0.17kWh ) (Running time in video 6:00 to 7:23) come out to £4,050 (€4,548) saving someone £12,348 (€13,868) over the diesel for running and maintenance costs.
If one had an even better electrical tariff of £0.05/kWh (€0.06kWh ) (running time in video 7:40 to 8:34) the running and maintenance cost of the van would be £1,550 (€1,740) saving someone £14,848 (€16,676) over the diesel for running and maintenance costs.
In the 21st century in order for EVs to gain competitive advantage over the internal combustion engines they need to increase their Energy Density and Power Density (how much energy they store and how quickly they can throughput this to the cars motor).
From the 1970’s till the mid 1980’s[10] there was considerable experimentation with battery development. Various combinations of lithium and other materials were tried in various combinations. One example was the combining of cathode and anode battery materials. A prototype of the Lithium-ion (Li-ion) battery[11] was developed in 1985 by Akira Yoshino who along with John Goodenough, Stanley Whittingham, Rachid Yazami and Koichi Mizushima are considered the forefathers of the Li-ion battery. By the early 1990s the first commercial Li-ion battery was developed.
Li-ion batteries' ability to recharge daily at any stage of their charge combined with their very good energy density[12] is what gives them the edge over other rechargeable batteries such as those using lead acid which has a very low comparative energy density. Nickel-cadmium and nickel–metal hydride batteries[13] also have a relatively low[14] comparative energy density and suffer from memory effect. In memory effect[15] a battery remembers how much it was discharged in previous discharges due to some crystal formation and doesn't fully charge again giving the impression that it has lost its capability to be fully charged again. These advantages of a much superior power density and the lack of the memory effect helped Li-ion batteries become the ideal choice for use in Electric Cars.
In 2008 Tesla was one of the first companies to introduce to the world a fully electric, road legal, mass produced, Li-ion battery electric car capable of travelling more than 200mi (320Km) on a single charge. This was the “Roadster”[16]. The “Tesla Roadster” was developed as a rival to many of the fastest sports cars with the main difference being that the Roadster was ‘full electric’ whereas the other comparable sports cars were gas powered. The Roadster showed the world that electric cars[17] could rival and match gas powered cars and were in no way inferior to them. On the contrary the Roadster was in some ways better and safer that the other sports cars.
Li-ion batteries however have problems. One of the most serious is their dependence on a good supply of the mineral ‘cobalt’. Originally cobalt constituted around 33% of a Li-ion battery. Today that component is as low as 3% and diminishing to a likely 0% in the very near future.
Since long before its first known isolation from other minerals in 1735[18] and until the early 20th century cobalt has been well known for its excellent heat and oxidation resistance. It has been used as a blue dye for glass and pottery[19]. For those same properties it has also been used in the construction of jet and gas turbines[20]. Cobalts abilities to act as a catalyst in the desulphurisation reactions[21] of refining crude oil in the creation and increasing of octanes in fuels such as petrol, diesel, kerosine, natural gas and others[22] have made cobalt a key ingredient for the oil industry.
While cobalt is essential to li-ion batteries, the mining of it has come under attack in recent years[23]. Some of the cobalt mines of the Democratic Republic of Congo especially, are said to use hand mining operations involving the use of child labor. Although there has been a great increase in global demand for cobalt the amount attributable to EVs is still a relatively small percentage of the overall demand.