what is the high-voltage battery within an ev comprised of

Part I. Composition of high-voltage electrical system

In pure electric vehicles, the high-voltage electrical system is mainly responsible for starting, driving, charging and discharging, and air conditioning power. It mainly includes battery system, powertrain, high-voltage electric control system, charging system, high-voltage equipment, and its wiring harness system.

Which contains.

1, battery system

Power battery PACK assembly: the "heart" of the electric vehicle, providing energy for all systems of the vehicle. When the power is consumed, it also needs to be charged. The power battery is a high-voltage direct current, its working voltage is generally 100~400V, the output current can reach 300A. Li-ion ternary battery and lithium iron phosphate battery are already the mainstream products at present. Generally speaking, EV power battery PACK consists of these parts: power battery module, structural system, electrical system, thermal management system and battery management system (BMS).

2、Powertrain

The powertrain of an electric vehicle is mainly composed of a drive motor and a motor controller (MCU). Motor controller MCU: converts high-voltage direct current into alternating current, and interacts with the vehicle controller and other modules to achieve effective control of the drive motor. Drive motor: according to the instructions of the motor controller, it converts electrical energy into mechanical energy and outputs it to the transmission system of the vehicle. At the same time, it can also convert the mechanical energy generated during driving (e.g. braking efficiency) into electrical energy, which can be delivered to the power battery through the on-board charger. The current mainstream drive motors are permanent magnet synchronous motor and three-phase AC asynchronous motor (Tesla).

3、High-voltage electric control system

High-voltage power distribution box (PDU): a power distribution device for the high-voltage power of the whole vehicle, similar to the electrical fuse box in the low-voltage circuit system.

Maintenance switch: between the power battery and PDU, when repairing the power battery, it can be used to cut off the high-voltage electricity of the whole vehicle to ensure maintenance safety, and is usually integrated in the PDU.

Voltage converter (DC/DC): Convert the high-voltage DC of the power battery into the low-voltage DC required by the vehicle's electrical appliances, and supply it to the battery to maintain the balance of the vehicle's power consumption.

On-board charger (OBC): a device that converts AC power to DC power.

Influenced by the vehicle layout, more and more models tend to integrate DC/DC and OBC into a two-in-one controller, or even PDU, DC/DC and OBC into a three-in-one controller.

4, charging system

Fast charging port: input high-voltage DC power, can be directly through the PDU to the power battery charging. Slow charging port: input high-voltage AC power, need to be converted by OBC, and then through the PDU to the power battery charging.

5、High-voltage equipment

The electric equipment on electric vehicles mainly includes steering power system, braking system, electric air conditioning and electric heating equipment. Steering power system: it consists of variable frequency drive and steering power oil pump, which assists the vehicle to turn the steering wheel and reduces the burden of people driving the vehicle. Braking System: It consists of variable frequency drive and electric air compressor, which provides compressed air to the braking system and suspension system to realise the braking function. Electricity Air-conditioning compressor and PTC heater: In order to regulate the temperature of the vehicle's interior space, electric vehicles are equipped with cold and warm air-conditioning or air-conditioning with PTC heating. Air conditioners and heaters are the major users of electricity in electric vehicles.

6. Wire Harness System

Electric vehicle electrical system components are connected through the wiring harness, both high-voltage harness and low-voltage harness. High-voltage wiring harness is the medium of high-voltage power transmission, which can be regarded as the "artery and blood vessels" of the electrical system, and the power of the power battery system "heart" - power battery is continuously transported to the various components in need. Low-voltage wiring harness can be regarded as the electrical system of the "neural network" and "capillaries", in addition to meet the traditional fuel car wiring harness function, but also responsible for the strong power control unit module function.

Part II, high-voltage electrical system development trend and characteristics

Electric vehicle system high-voltage electrical system is gradually integrated, modular development, and gradually derived from the electric vehicle "three big things": battery system, powertrain, high-voltage electronic control.

1, the integration of high-voltage electronic control

Characteristics: cost reduction, space saving, reduction of high-voltage wiring harness, increased reliability.

2, the integration of the drive system

Features: compact structure, high reliability, low cost, high efficiency. 

3、Total integration of high-voltage electrical system

Features: cost reduction, high integration, high electrical efficiency, simplified production process.

4、Battery system performance improvement

Features: safety, energy density improvement, power density improvement, SOC precision improvement, cycle life improvement.

Accelerated localisation of key materials for power batteries, performance indicators steadily improved, the cost is significantly reduced; monomer, battery pack, BMS and other aspects of safety technology research comprehensively. Performance: lithium iron phosphate power battery monomer specific energy up to 150Wh/kg, ternary lithium battery monomer specific energy up to 230Wh/kg; cost: power battery overall downward trend, power battery system cost a drop to 2 yuan / watt hour below

And lithium batteries to enhance the space for all to see, now all areas are replaced by a large number of lithium iron phosphate batteries, and our production capacity is also far ahead!