Cooling System for EV Battery

Contact us today for the perfect temperature control solution

In electric vehicles, the cooling system is mainly divided into two parts: one is to cool the drive motor, vehicle controller and DC/DC of the power system. The second is to cool the power lithium battery and car charger of the power supply system.

At present, the power lithium batteries of electric vehicles are lithium-ion batteries. The performance of lithium-ion power lithium batteries is sensitive to temperature changes. The loading space on the vehicle is limited, and the number of batteries required by the vehicle is large, and the batteries are closely arranged and connected. When the vehicle is running under different driving conditions such as high speed, low speed, acceleration, deceleration, etc., the battery will be discharged at different rates, and a large amount of heat will be generated at different heat generation rates. In addition to time accumulation and space effects, uneven heat accumulation will occur. , resulting in complex and changeable operating environment temperature of the battery pack.

The cooling performance of the power lithium battery directly affects the efficiency of the battery, and also affects the battery life and safety. During the charge and discharge process, the battery itself will generate a certain amount of heat, which will cause the temperature to rise, and the temperature rise will affect many characteristic parameters of the battery, such as internal resistance, voltage, SOC, available capacity, charge and discharge efficiency and battery life.

In order to maximize the performance and life of the battery pack, it is necessary to optimize the structure of the battery pack, conduct thermal management on it, add heat dissipation facilities, and control the temperature environment in which the battery operates.

Primary EV battery cooling methods

Different thermal management systems, different types of components, different structures, different weights, different system costs and different control methods, make the performance of the system different. When choosing the type of battery pack thermal management system design, the cooling performance requirements of the battery should be taken into consideration, combined with the performance of the vehicle and the size of the space, the stability and cost of the system are also factors to be considered.

1. Air cooling

There are mainly the following cooling methods for electric vehicle battery packs: air cooling, liquid cooling, and heat pipe cooling. At present, the air cooling method is still an important method. Air cooling is relatively easy to implement, but the cooling effect is not good.

2. Liquid cooling

Liquid cooling has a better cooling effect and can make the temperature distribution of the battery pack uniform, but liquid cooling has high requirements on the sealing of the battery pack. If a conductive liquid such as water is used, a water jacket is required to seal the liquid and the battery cells. The body is separated, which not only increases the complexity of the system but also reduces the cooling effect.

Generally, the cooling system is installed near the battery pack module. The principle is similar to that of an air conditioner. The cooling system is connected to a single battery module through pipelines. The cooling system cools the ethylene glycol, and the excess heat is discharged to the outside through the fan, and the ethylene glycol recirculates into the battery module to continue to absorb the heat emitted by the battery.

3. Heat pipe technology

Heat pipe technology can meet the requirements of high-temperature heat dissipation and low-temperature preheating of battery packs, with fast response and good temperature uniformity. After being proposed as a new cooling method for battery packs, it has developed to a certain extent and has become a key direction of industrial research. , but due to layout and volume constraints, there is no real car use yet.

Judging from the existing cooling methods of electric vehicle power lithium batteries, air cooling has always occupied an important position, especially Japanese electric vehicles, which basically use air cooling systems. As the application environment has higher and higher requirements for batteries, liquid cooling has also become a preferred method for car companies. my country’s mainstream electric passenger car companies have also begun to turn to liquid cooling systems. From the perspective of medium and long-term trends, liquid cooling will occupy the mainstream.

Important components of battery pack cooling system

Different cooling systems have corresponding cooling components: the important part of the air cooling system is the fan, and the important part of the liquid cooling system is the cooling plate.

Air cooling system components: cooling air duct, fan, resistance wire

The selection of the fan directly affects the cooling effect of the battery pack air cooling system. The fan selection requirements are as follows: determine the air flow according to the heat generation rate of the battery; meet the temperature rise requirements of each module; select a fan that meets the requirements based on the air flow required by the system and the pressure drop curve of the system.

Liquid cooling system components: water cooling pipes, cooling pumps, cooling valves, cooling plates

The cooling plate is one of the most critical components in the liquid cooling system of the battery pack, and the selection of the cooling plate is very important. The selection of the cooling plate must meet the following requirements: the pressure drop of the cooling plate must meet the customer’s requirements; the consistency of the cooling water flow; the burst pressure requirements; the mechanical requirements of the cooling plate; Tolerance requirements and space dimension requirements must be met.

There are many manufacturers of battery cooling system components, and most of the important components are supplied by traditional electric companies. At present, battery management system companies and PACK assembly companies are also involved in the production of customized products.

Email: info@lneya.com    WeChat ID: +8615251628237    WhatsApp: +86 17851209193