Today, electric motors are taking over the automotive industry. We often think of the electrification of the industry as a movement away from fossil fuels to reduce global emissions. But there are other, less obvious implications that are affecting electric motor manufacturers and consumers.
Here are 7 ways the industry is changing:
- Simpler Design with Fewer Moving Parts
- Easier Temperature Management
- No Toxic Gasses to Manage
- Instant Torque at the Wheels
- Less Pressure on Quality Assurance
- Simplified Supply Chain Due to Smaller BOM
- Improved Security
Unlike a gasoline internal combustion engine with hundreds of moving parts, Tesla electric motors have only one moving piece: the rotor.
Extract from the Tesla Model S pamphlet
Tesla’s design demonstrates that electric motors have a much lower number of moving parts than internal combustion engines. This statement is true for other parts of the electric vehicle as well. Tesla’s electric drivetrains, for example, have about 20 moving parts compared to traditional drivetrains that have around 200 moving parts.
For consumers, this means that electric motors—and electric vehicles in general—are a lot more reliable, as there is less mechanical wear.
Parts that are no longer needed include oil pumps, fuel pumps, air intake systems, air filters, chains, pistons, alternators, clutches, connecting rods, valves, springs, pressure regulators, ignition leads, and a lot more.
For manufacturers, this drastically simplifies the motor design.
Electric motors are extremely efficient, losing only ≈10% of energy in the form of heat compared to ≈70% for combustion engines. This means that less heat is generated in the motor, making temperature management much easier for motor manufacturers.
Electric motors are exposed to less heat and don’t have to withstand as much high temperatures and thermal stress. This makes it possible to use more efficient materials for the motor’s components.
When combustion engines burn fuel, they generate toxic gasses that need to be converted into less-toxic pollutants before they are released into the atmosphere. Since electric motors do not generate toxic gasses, all the components of the exhaust system are not needed. These include parts like cylinder heads, exhaust lines, turbochargers, catalytic converters, and mufflers.
Torque is the force that causes wheels to rotate. In combustion engines, that force is optimal at about 1,800 –2,600 rpm (a sweet spot that varies from engine to engine). Gas engines will provide suboptimal torque at low and high rpm. But electric motors are different: they can deliver instant and optimal torque at the wheels, regardless of the rpm.
As a result, electric motors don’t need a transmission (also known as a gearbox) to change gears and remain optimal. Many electric cars function with what is called a single-speed transmission, while others (like the Tesla Model S) have no transmission at all, eliminating the need for hundreds of complex moving parts that come with it such as gears.
Tolerances of pieces used in internal combustion engines are extremely tight—and you won’t see an equivalent in electric motors. Pistons and cylinders, for example, are fabricated to micrometer tolerances at multiple places inside the engine. The gap between them must be controlled with extreme precision to achieve proper combustion. To meet this need, the manufacturing process must be precise and consistent, with acceptable deviations in the ten-thousandths of an inch (or 2.54 microns) range.
Electric motors eliminate these parts with tight tolerances. As a result, quality assurance is easier and there’s a lower risk of rework and rejects.
The bill of materials (BOM) is a structured list of all the materials, components, and parts needed to build the motor. It includes details on quantities, procurement, cost, and so on.
The smaller BOM of electric motors will have a major impact on the automotive industry’s supply chain. Suppliers of parts which are not needed in EVs, such as exhaust systems, fuel systems, and transmissions, face the risk of becoming irrelevant. As EVs become more mainstream, these motor part providers will need to adapt to survive.
For electric motor manufacturers, a smaller BOM is a good thing. It offers a range of benefits, including:
- Simplified supplier relationships and reduced supply chain complexity due to a lower number of suppliers.
- Reduced lead times, as fewer items need to be sourced and coordinated.
- Improved inventory management due to smaller number of components that need to be tracked, managed, and kept in stock.
- Lower risk of back ordered parts that create delays in production.
With their smaller list of components, electric motors are more compact than combustion engines. This leaves more room to optimize the crumble zone—which is the areas at the car’s front and rear that can absorb impacts and protect passengers.
Other factors also contribute to safety:
- The greater weight of the car absorbs more energy from shocks
- The lower center of gravity provides resistance to rollovers
- Electric cars tend to have the latest crash avoidance and survival technologies
- Electric cars have lower risks of fire (they don’t carry a tank full of flammable fuel)
Not surprisingly, many electric cars have received top safety ratings in crash tests and have been shown safer overall than gas-powered cars.
The Challenge? Meeting the Demand
While electric motor manufacturing is bringing positive changes to the industry, OEMs and their suppliers still need to overcome many challenges. One of them is the creation of new motor production lines that can scale to meet the growing demand for electric vehicles. With limited time and resources, manufacturers are under pressure to take the right decisions.
How Lasers Can Help Electric Motor Manufacturers
Laser technology can ensure surface processing operations are efficient and precise for all motor types, including brushless DC motors, permanent magnet synchronous motors, AC induction motors, interior permanent magnet motors, permanent magnet switched reluctance motors, and so on.
Examples of applications include:
- Stripping of the insulating layer on the stator’s copper hairpins (for hairpin motors)
- Oxide removal from slip rings to improve the electrical contact
- Identification of rotor laminations or squirrel cages for traceability
- Epoxy powder coating removal from bridges and connector tabs
- Battery tab welding