Electric bicycle

In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895, Ogden Bolton Jr. was granted a patent for a battery-powered bicycle with "6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel" (U.S. Patent 552,271). There were no gears and the motor could draw up to 100 amperes from a 10-volt battery.[3]

Two years later, in 1897, Hosea W. Libbey of Boston invented an electric bicycle (U.S. Patent 596,272) that was propelled by a "double electric motor". The motor was designed within the hub of the crankset axle.[4] (This model was later re-invented and imitated in the late 1990s by Giant Lafree e-bikes.)

By 1898, a rear-wheel drive electric bicycle, which used a driving belt along the outside edge of the wheel, was patented by Mathew J. Steffens. An 1899 patent by John Schnepf (U.S. Patent 627,066) depicted an electric bicycle with a rear-wheel friction, "roller-wheel"-style drive.[5] In 1969, Schnepf's invention was expanded by G. A. Wood Jr. (U.S. Patent 3,431,994). Wood's device used four fractional horsepower motors connected through a series of gears.[6]

The Japanese automotive giant Yamaha built a prototype e-bike in 1989, and invented the pedal assist system in 1993.[7]

From 1992, Vector Services Limited offered the Zike e-bike.[8] The bicycle included NiCd batteries that were built into a frame member and included an 850 g permanent-magnet motor.

Apart from the Zike, in 1992, hardly any commercial e-bikes were available. However, in a 10-year period from 1993 onwards, production grew by an estimated 35%. According to Gartner, regular bicycle production decreased from its peak 107 million units (1995).

Torque sensors and power controls were developed during the late 1990s. For example, a Japanese patent (6163148) was granted in 1997 to a team led by Yutaka Takada,[9] for a "Sensor, drive force auxiliary device ... and torque sensor zero point adjusting mechanism".

American car executive Lee Iacocca founded EV Global Motors in 1997, a company that produced an electric bicycle model named E-bike SX, and it was one of the early efforts to popularize e-bikes in the US.[10]

Some of the less expensive e-bikes used bulky lead-acid batteries, whereas newer models generally used NiMH, NiCd, and/or Li-ion batteries, which offered lighter, denser capacity batteries. Performance varies; however, in general there is an increase in range and speed with the latter battery types.

By 2001, the terms e-bike, power bike, pedelec, pedal-assisted, and power-assisted bicycle were commonly used to refer to e-bikes. By contrast, the terms "electric motorbike" or "e-motorbike" referred to more powerful models that attain higher speeds (up to 80 km/h (50 mph) or higher).

By 2007, e-bikes were thought to make up 10 to 20 percent of all two-wheeled vehicles on the streets of many major Chinese cities.[11] A typical unit requires eight hours to charge the battery, which provides the range of 25 to 30 miles (40 to 48 km),[11] at the speed of around 20 km/h (12 mph).[12]

• 
  E-bike 1932 (by Philips & Simplex)
• 
  A bike equipped with an after market electric hub motor conversion kit, with the battery pack placed on the rear carrier rack
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  Brushless DC electric motor (BLDC) bicycle hub motor

E-bikes with pedal-assist only are usually called pedelecs but can be broadly classified into pedelecs proper and the more powerful S-Pedelecs.

The term "pedelec" (from pedal electric cycle) refers to a pedal-assist e-bike with a relatively low-powered electric motor and a decent but not excessive top speed. Pedelecs are legally classed as bicycles rather than low-powered motorcycles or mopeds.

The most influential definition of pedelecs comes from the EU. EU directive (EN15194 standard) for motor vehicles considers a bicycle to be a pedelec if:

• The pedal-assist, i.e. the motorised assistance that only engages when the rider is pedalling, cuts out once

1. 25 km/h (16 mph) is reached, and
2. when the motor produces maximum continuous rated power of not more than 250 W (0.34 hp) (n.b. the motor can produce more power for short periods, such as when the rider is struggling to get up a steep hill).

An e-bike conforming to these conditions is considered to be a pedelec in the EU and is legally classed as a bicycle. The EN15194 standard is valid across the whole of the EU and has been adopted by some non-EU European nations including the UK,[14] and also some non-European jurisdictions (such as the state of Victoria in Australia).[15]

Pedelecs are much like conventional bicycles in use and function—the electric motor only provides assistance, for example, when the rider is climbing or struggling against a headwind. Pedelecs are therefore especially useful for people in hilly areas where riding a bike would prove too strenuous for many to consider taking up cycling as a daily means of transport. They are also useful for riders who more generally need some assistance, e.g. for people with heart, leg muscle or knee joint issues.

More powerful pedelecs which are not legally classed as bicycles are dubbed S-Pedelecs (short for Schnell-Pedelecs, i.e. Speedy-Pedelecs) in Germany. These have a motor more powerful than 250 W (0.34 hp) and less limited, or unlimited, pedal-assist, i.e. the motor does not stop assisting the rider once 25 km/h (16 mph) has been reached. S-Pedelec class e-bikes are therefore usually classified as mopeds or motorcycles rather than as bicycles and therefore may (depending on the jurisdiction) need to be registered and insured, the rider may need some sort of driver's license (either car or motorcycle) and motorcycle helmets may have to be worn.[16] In the United States, many states have adopted S-Pedelecs into the Class 3 category, limited to not more than 750 W (1.01 hp) of power and 28 mph (45 km/h) speed.[17] In Europe they are likely to be classed as mopeds requiring a registration plate and a licensed driver [18]

Some newer electric bikes include a pedal assist system (PAS) with or without throttle, allowing riders to pedal while using the electric motor to increase range. There are electric propulsion conversion kits for ordinary bicycles.

Some e-bikes have an electric motor that operates on a power-on-demand basis only; the motor is engaged and operated manually using a throttle, with control usually on the handgrip as on a motorbike or scooter. These sorts of e-bikes often, but not always, have more powerful motors than pedelecs.

With power-on-demand only e-bikes the rider can:

1. ride by pedal power alone, i.e. fully human-powered.
2. ride by electric motor alone by operating the throttle manually.
3. ride using both together at the same time.

Some power-on-demand only e-bikes are very different from, and cannot be classified as, bicycles. For example, the Noped is a term used by the Ministry of Transportation of Ontario for e-bikes which are not fitted with pedals.

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  E-bikes and electric scooters in a specialized shop in Beijing in 2008. (Y2750 is around US$400.)
• 
  E-bikes are common in China, with an estimated fleet of 120 million in early 2010.[44]
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  Hybrid bicycle speedometer with integrated battery level measurement
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  Yellow electric bike on West 54th Street
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  e-Bikes in Split, Croatia
• 
  E-bikes in Berlin

The two most common types of motors used in electric bicycles are brushed and brushless. Many configurations are available, varying in cost and complexity; direct-drive and geared motor units are both used. An electric power-assist system may be added to almost any pedal cycle using chain drive, belt drive, hub motors or friction drive. Brushless hub motors are the most common in modern designs. The motor is built into the wheel hub itself, while the stator is fixed solidly to the axle, and the magnets are attached to and rotating with the wheel. The bicycle wheel hub is the motor. The power levels of motors used are influenced by available legal categories and are often, but not always limited to under 750 watts. With a front-drive the motor sits in the front hub, and with a rear-drive the motor sits in the rear hub.

Another type of electric assist motor, often referred to as the mid-drive system, is increasing in popularity. With this system, the electric motor is not built into the wheel but is usually mounted near (often under) the bottom bracket shell. In more typical configurations, a cog or wheel on the motor drives a belt or chain that engages with a pulley or sprocket fixed to one of the arms of the bicycle's crankset. Thus, the propulsion is provided at the pedals rather than at the wheel, being eventually applied to the wheel via the bicycle's standard drive train. Freewheel crank, that is a freewheel in the bottom bracket, is a necessary part in mid-drive systems to allow the electric motor to work inside its optimal rotational speed range (r/min).

Because the power is applied through the chain and sprocket, power is typically limited to around 250–500 watts to protect against fast wear on the drivetrain. An electric mid-drive combined with an internal gear hub at the back hub may require care due to the lack of a clutch mechanism to soften the shock to the gears at the moment of re-engagement. A continuously variable transmission or a fully automatic internal gear hub may reduce the shocks due to the viscosity of oils used for liquid coupling instead of the mechanical couplings of the conventional internal gear hubs.[50]

The main advantage mid-drive motors have over hub motors is that power is applied through the chain (or belt) and thus it uses the existing rear gears (either external or internal). This allows for the motor to operate more efficiently at a wider range of vehicle speeds. Without using the bicycle's gears, equivalent hub motors tend to be less effective propelling the ebike slowly up steep hills and also propelling the ebike fast on the flat.

E-bikes use rechargeable batteries in addition to electric motors and some form of control. Battery systems in use include sealed lead–acid (SLA), nickel–cadmium (NiCad), nickel–metal hydride (NiMH) or lithium-ion polymer (Li-ion). Batteries vary according to the voltage, total charge capacity (amp hours), weight, the number of charging cycles before performance degrades, and ability to handle over-voltage charging conditions. The energy costs of operating e-bikes are small, but there can be considerable battery replacement costs. The lifespan of a battery pack varies depending on the type of usage. Shallow discharge/recharge cycles will help extend the overall battery life.

Range is a key consideration with e-bikes, and is affected by factors such as motor efficiency, battery capacity, efficiency of the driving electronics, aerodynamics, hills and weight of the bike and rider.[51][52] Some manufacturers, such as the Canadian BionX or American Vintage Electric Bikes,[53] have the option of using regenerative braking, the motor acts as a generator to slow the bike down prior to the brake pads engaging.[54] This is useful for extending the range and the life of brake pads and wheel rims. There are also experiments using fuel cells. e.g. the PHB. Some experiments have also been undertaken with super capacitors to supplement or replace batteries for cars and some SUVS. E-bikes developed in Switzerland in the late 1980s for the Tour de Sol solar vehicle race came with solar charging stations but these were later fixed on roofs and connected so as to feed into the electric mains.[55] The bicycles were then charged from the mains, as is common today. While e-bike batteries were produced mainly by bigger companies in past, many small to medium companies have started using innovative new methods for creating more durable batteries. State of the art, custom built automated precision CNC spot welding machines[56] created 18650 battery packs[57] are commonly used among do-it-yourself e-bike makers.

Electric trikes have also been produced that conform to the e-bike legislation. These have the benefit of additional low speed stability and are often favored by people with disabilities. Cargo carrying tricycles are also gaining acceptance, with a small but growing number of couriers using them for package deliveries in city centres. Latest designs of these trikes resemble a cross-between a pedal cycle and a small van.[68]

• 
  Diagram illustrating a standard bicycle converted to an e-bike using a retail conversion kit
• 
  A folding e-bike
• 
  A modern electric cargo trike in use in London, with a payload of up to 250 kg (550 lb)

Schleinitz et al. (2014) concluded that e-bike users in Germany were no more likely than conventional cyclists to be involved in "safety-critical situations". However, Dozza et al. (2015) concluded (from an analysis of Swedish cyclists) that e-bikers may be involved in more critical incidents but with "lower severity". Additionally, e-bikers were less likely to have dangerous interactions with motorized vehicles.[76]

China has experienced an explosive growth of sales of non-assisted e-bikes including scooter type, with annual sales jumping from 56,000 units in 1998 to over 21 million in 2008,[89] and reaching an estimated fleet of 120 million e-bikes in early 2010.[44][90] This boom was triggered by Chinese local governments' efforts to restrict motorcycles in city centers to avoid traffic disruption and accidents. By late 2009 motorcycles are banned or restricted in over ninety major Chinese cities.[89] Users began replacing traditional bicycles and motorcycles and e-bike became an alternative to commuting by car.[44] Nevertheless, road safety concerns continue as around 2,500 e-bike related deaths were registered in 2007.[90] By late 2009 ten cities had also banned or imposed restrictions on e-bikes on the same grounds as motorcycles. Among these cities were Guangzhou, Shenzhen, Changsha, Foshan, Changzhou, and Dongguang.[89][90]

In April 2019, the China's regulatory policies change, new standards around electric bikes were introduced, governing things like a bicycle's weight, maximum speed and nominal voltage.[91] Vehicles which apply the new standard, including international 25 km/h speed limit, are legally considered as bicycles and do not require registration. E-bikes out of this standard are considered as motorcycles subject to helmet and license regulation.[92]

China is the world's leading manufacturer of e-bikes, with 22.2 million units produced in 2009. Some of the biggest manufacturers of E-bikes in the world are BYD and Geoby. Production is concentrated in five regions, Tianjin, Zhejiang, Jiangsu, Shandong, and Shanghai.[93] China exported 370,000 e-bikes in 2009.[94] In 2019, about 223,000 China companies were in businesses related to the electric-bike industry.[91]

The Netherlands has a fleet of 18 million bicycles.[95] E-bikes have reached a market share of 10% by 2009, as e-bikes sales quadrupled from 40,000 units to 153,000 between 2006 and 2009,[96] and the electric-powered models represented 25% of the total bicycle sales revenue in that year.[95] By early 2010 one in every eight bicycles sold in the country is electric-powered despite the fact that on average an e-bike is three times more expensive than a regular bicycle.[90][96] E-bike sales have now overtaken those of unpowered bikes, reaching 423,000 in 2019 and 547,000 in 2020.

A 2008 market survey showed that the average distance traveled in the Netherlands by commuters on a standard bicycle is 6.3 kilometres (3.9 mi) while with an e-bike this distance increases to 9.8 kilometres (6.1 mi).[97] This survey also showed that e-bike ownership is particularly popular among people aged 65 and over, but limited among commuters. The e-bike is used in particular for recreational bicycle trips, shopping and errands.[97]

In 2009 the U.S. had an estimated fleet of 200,000 e-bikes.[94] In 2012 they were increasingly favored in New York as food-delivery vehicles.[98] The North American Electric Bike Market is expected to grow at a CAGR of 10.13% from 2021 to 2028.[99]

In India electric bicycles market was valued at US$1.14 million in 2021, and is expected to reach US$2.31 million by 2027, projecting a CAGR of 12.69% during this forecast period.[100]