For new energy vehicles, battery, VCU, BSM, and motor efficiency all lack room for improvement. The most room for improvement is the motor drive part, and the core component of the motor drive part IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) Type transistor chip) is the most important thing.

IGBT accounts for about half of the cost of the motor drive system, and the motor drive system accounts for 15-20% of the cost of the entire vehicle. That is to say, IGBT accounts for 7-10% of the cost of the entire vehicle. It is the second most expensive component besides the battery. It also determines the energy efficiency of the vehicle.

Not only do motor drives use IGBTs, but also new energy generators and air conditioners generally require IGBTs. Not only new energy vehicles, but the core of DC charging piles and locomotives (high-speed rail) are also IGBT tubes. 30% of the raw material cost of DC charging piles is IGBT. Electric locomotives generally require 500 IGBT modules, EMUs require more than 100 IGBT modules, and a subway requires 50-80 IGBT modules.

In 2016, the global sales of electric vehicles were about 2 million, and a total of about 900 million US dollars of IGBT tubes were consumed, with an average of about 450 US dollars per vehicle. It is the most expensive component in electric vehicles except for batteries.

Among them, there are about 770,000 hybrids and PHEVs, each requiring about 300 US dollars of IGBTs, and about 1.23 million pure electric vehicles. On average, each vehicle uses 540 US dollars of IGBTs. High-power pure electric buses may use IGBTs. More than $1,000.

What is IGBT?

IGBT is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar transistor) and MOS (insulated gate field effect transistor).

Compared with various previous power electronic devices, IGBT has the following characteristics: high input impedance, can use general low-cost driving circuit; high-speed switching characteristics; low loss in the conduction state.

IGBT has the advantages of both the high input impedance of MOSFET and the low on-voltage drop of GTR. It has obvious advantages in comprehensive performance. It is very suitable for use in converter systems with DC voltages of 600V and above, such as AC motors, inverters, Switching power supply, lighting circuit, traction drive and other fields.

For hybrid power, in addition to the drive motor, there is also a generator, which can be driven by the car's engine to generate electricity, and then charge the battery through the IGBT module AC/DC conversion. In the DM model, the generator can also act as a driving motor.

A smallest full-function unit on a wafer is called a cell. The smallest unit after wafer splitting is a chip unit that constitutes an IGBT single tube or a unit of a module, collectively called the IGBT die.

An IGBT die is called a unit of the module, which is also called a module unit or die of a module. The difference between the module unit and the IGBT die is in the final product. The module unit does not have an independent package, and the die has an independent package, becoming an IGBT tube.

Recently, there is also a module called IPM, which also encapsulates the gate-level drive and protection circuit into the IGBT module. This is for the laziest engineers, but the operating frequency should not be too high.

The price of a single tube is much lower than that of a module, but the reliability of a single tube is far less than that of a module. Except for Tesla and those low-speed electric vehicles, all of the world uses modules. Only Tesla attaches much greater importance to cost than to human lives.

Tesla Model X uses 132 IGBT tubes, which are provided by Infineon. Among them, there are 96 rear motors and 36 front motors. The price of each single tube is about 4-5 US dollars, which is about 650 US dollars in total.

If you switch to modules, it is estimated that 12-16 modules will be required, and the cost will be approximately US$1200-1600. The main reason for Tesla's use of single-tube is cost, especially its power is much larger than that of ordinary electric vehicles. In addition, the design and development cycle is short, and single-tube design is forced.

Compared with BMW I3, it adopts Infineon’s new HybridPACK 2 module design. Each module contains 6 single-tube IGBTs, 750V/660A, and the current is very large. Only two modules are needed. The volume is greatly reduced and the cost is about 300 US dollars.

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