If the whole vehicle is compared to a person, thermal management is the temperature regulation center of the whole car. It controls the temperature of all the core components of the vehicle, taking into account the three-power safety, power stability, driving comfort, but also the key track for car companies to open the gap between endurance and control the cost of the vehicle.
What Does Thermal Management Really Manage? Four Control Objects
Different from traditional fuel vehicles (only engine heat dissipation + cabin air conditioning), the thermal management of electric vehicles belongs to global temperature control, covering the four core parts of the vehicle: battery, electronic control, passenger cabin and auxiliary parts.
Power battery [highest priority]
Battery is the core of pure electric vehicle and the most sensitive component to temperature.
Temperature directly determines battery safety, service life, charging efficiency and actual vehicle endurance:
- High temperature:it is extremely easy to cause thermal runaway of the battery core, causing potential safety hazard of fire;
- Low temperature:the activity of the electrolyte becomes poor, the endurance is cut in half, and the charging speed is greatly slowed down;
- Temperature difference:If the temperature difference of the battery cell in the battery pack is too large, the attenuation of the battery will be aggravated and the service life will be shortened.
Electric drive and high voltage electric control system
Including drive motor, motor controller MCU, on-board charger OBC, DC-DC, high voltage distribution box PDU and other high voltage components.
In the whole process of vehicle driving and charging, such components will continuously generate high heat. If the heat dissipation is not timely, it will trigger the power limit of the whole vehicle, weaken the power, accelerate the aging of components, and directly cause high voltage failure in serious cases.
Crew cockpit
It is also the most intuitive part for users to perceive. The core services for drivers and passengers include cabin cooling/heating, front and rear windshield defrosting and defogging, seat heating/ventilation, steering wheel heating, etc. It not only improves the comfort of travel, but also directly guarantees the safety of driving by defrosting and defogging.
Auxiliary components
It covers small components such as high-voltage wiring harness, charging interface, braking system and various electronic control valve bodies to avoid the risk of failure caused by extreme high and low temperature environment and ensure the all-weather stable operation of the whole vehicle.
Core function of thermal management: more than air conditioning
Battery global temperature control (core priority)
- Cooling:fast charging, high-speed driving, climbing, summer high temperature conditions, quickly take away the battery heat, avoid the risk of thermal runaway;
- Heating:preheat the battery in low temperature environment in winter, activate the activity of the battery cell, and improve the charging speed and vehicle discharge power;
- Uniform temperature:accurately control the temperature difference of the battery cell in the battery pack ≤ 2 ℃ to delay the attenuation of the battery from the root;
- Heat preservation:slow down the temperature loss when parking and standing, and reduce the energy consumption loss when starting the vehicle next time.
Lectric drive electric control constant temperature protection
Real-time heat dissipation and cooling for the motor, electric control and charger; Complete preheating in low temperature environment, ensure stable power output, and eliminate the problems of high temperature frequency reduction and power limitation.
Cabin comfort adjustment
Seasonal temperature self-adaptive adjustment, taking into account refrigeration, heating, defogging, ventilation, to meet the diverse comfort needs of users in an all-round way.
Waste heat recovery (exclusive advantages of electric vehicles)
This is also the greatest value of electric thermal management.
Collect the waste heat generated by the motor, electronic control and battery, use it for cabin heating and battery preheating, replace the high energy consumption PTC heating, directly reduce the power consumption of the whole vehicle, and increase the winter endurance by 10% -15%.
Full-scene vehicle safety protection
It is suitable for all driving scenarios such as extreme cold, hot summer, high speed, fast charging, parking and climbing, and is equipped with over-temperature warning, automatic power limiting and fault protection mechanisms to protect the safety of high-voltage parts and vehicles in an all-round way.
Integrated Thermal Management: From Decentralization to Convergence
What is distributed thermal management?
Early entry-level electric vehicles generally adopt a decentralized scheme: the three circuits of battery, electric drive and cockpit are independent of each other, each equipped with its own water pump, heat exchanger, pipeline and valve body.
The disadvantages are very obvious: redundant parts, large cabin space, high vehicle weight, waste heat can not be exchanged, high energy consumption, and high failure rate in the later period.
Integrated thermal management
Break the circulation barrier between systems, integrate the valve body, heat exchanger, water pump, sensor and other scattered components into an integrated module, with a common pipeline and multi-way valve structure.
It is dispatched by the exclusive thermal management controller and distributes the heat of the whole vehicle on demand to realize the intelligent switching of cooling, heating and waste heat recovery modes.
Four core advantages of integrated solution
- Cost reduction and range increase:the utilization rate of waste heat is increased by more than 30%, and the endurance in winter is increased by 10% -20%;
- Lightweight and space-saving:the number of pipelines and parts is greatly reduced, which is suitable for the compact cabin layout of electric vehicles;
- Safety upgrade:reduce pipeline joints and reduce the risk of coolant leakage; The temperature control precision is higher;
- Global adaptation:a set of system adapts to all working conditions and can easily cope with extreme cold/heat weather.
Integrated three-tier solution
According to the integration level from low to high, it is divided into three levels to adapt to different price models:
- Partial integration (entry level): only the internal parts of a single system are integrated, the cross-system circuit is independent, the cost is low, and it is mostly used for low-end electric vehicles;
- Regional integration (mainstream level): get through the battery + electric drive double cycle, can recover the waste heat of the motor to preheat the battery, the cockpit system is independent, the first choice for mid-end models, the most cost-effective;
- Global integration (high-end): The three major systems of battery, electric drive and cockpit are fully interoperable, with two-way integration of refrigerant + water medium and high-efficiency heat pump system, which is also the standard scheme of current high-end models.
A set of global energy dispatching system, which takes into account safety, power, comfort and energy consumption, is the core key technology of electric vehicle, which is second only to the three-power system.
The development trend is also very clear: decentralized → regional integration → global heat pump integration.
In the future, with the iteration of technology, water-free thermal management, AI intelligent thermal control and integrated vehicle energy management will become the new competitive commanding heights of major automobile enterprises.
