Description:

With the development of new energy power batteries, the development of high-density, high-power, and fast-charging/discharging new energy vehicles is encouraged. The previous new energy vehicles using air-cooling for heat dissipation cannot effectively solve the battery cooling issue. The advantages of liquid cooling systems include fast cooling rate, good temperature uniformity, and simple fluid (temperature and flow rate) control. Liquid cooling heat dissipation systems have become an inevitable trend in new energy vehicles. The thermal management system of the entire vehicle needs to be redesigned.

Currently, there is a lack of operational data for the liquid cooling heat dissipation system of battery packs, which prevents new energy vehicle manufacturers from designing the vehicle’s liquid cooling system. The vehicle manufacturers need to understand the following data: 1)The reasonable temperature range for the battery pack is 10-30°C. In cold weather, the liquid cooling system may reach -30°C. The battery pack has a preheating function to provide thermal protection before startup. When the battery temperature exceeds 30°C during vehicle operation, it needs to be cooled down by the -30°C liquid cooling system. Flow rate adjustment of the liquid is required to control the battery temperature within the range of 10-30°C. Assuming the vehicle’s liquid cooling system has a fixed pipe diameter, the flow rate needs to be adjusted by controlling the pressure as the coolant temperature changes. Likewise, as the coolant temperature in the vehicle changes, the flow rate and pressure of the coolant for battery temperature cooling also need to change; 2)In hot weather, the coolant temperature and battery pack temperature can exceed 50°C. The cooling system of the vehicle (including the interior air conditioning, battery pack, electric drive, and engine liquid cooling system) needs to match the heat load to achieve fast thermal balance and ensure vehicle performance and safety within a reasonable range. These data need to be provided by our liquid cooling thermal test platform.

Thermal issues in batteries are critical factors that determine their performance, safety, lifespan, and usability. Firstly, the temperature of lithium-ion batteries directly affects their energy and power performance during use. When the temperature is low, the available capacity of the battery will rapidly decay. Charging the battery at temperatures below 0°C can cause instantaneous overvoltage, leading to lithium plating and potential short circuits. Secondly, thermal issues in lithium-ion batteries directly impact their safety. Defects in manufacturing or improper handling during use can cause localized overheating, triggering a chain reaction of heat release and potentially resulting in smoke, fire, or even explosions, posing a significant threat to the lives of vehicle occupants. Additionally, the operating or storage temperature of lithium-ion batteries affects their lifespan. The optimum temperature range for battery operation is approximately 10-30°C, and temperatures that are too high or too low can cause accelerated degradation of battery life. The increased size of power batteries reduces the ratio of surface area to volume, making it more challenging to dissipate internal heat. This can lead to uneven internal temperatures and excessive localized temperature, further accelerating battery degradation and reducing lifespan, which ultimately affects user satisfaction.

The battery thermal management system is crucial for addressing thermal issues in batteries, and it is one of the key technologies for the performance, safety, and lifespan of power batteries.

The main functions of the thermal management system include:

Effective heat dissipation when the battery temperature is high to prevent thermal runaway accidents.

Preheating the battery when the temperature is low to improve the charging and discharging performance and safety at low temperatures.

Reducing temperature differences within the battery pack, suppressing the formation of hotspots, preventing rapid deterioration of batteries in high-temperature areas, and prolonging the overall lifespan of the battery pack.

The temperature environment inside the battery pack has a significant impact on the reliability, lifespan, and performance of battery cells. Therefore, it is crucial to maintain a certain temperature range within the pack. This can be achieved through cooling and heating processes. Here, we will provide a brief introduction to liquid cooling cooling methods.

Water Cooling:

Water cooling technology uses liquid flow for heat transfer to dissipate the heat generated by the battery, thus reducing the battery temperature. Liquid media have high heat transfer coefficients, large heat capacities, and fast cooling speeds. They are effective in reducing high temperatures and ensuring temperature uniformity within the battery pack. Additionally, liquid cooling systems have relatively small system volumes. Liquid cooling systems can be implemented in various ways: immersing battery cells or modules in coolant, incorporating cooling channels between battery modules, or using cooling plates at the bottom of the battery pack. When the battery is in direct contact with the liquid, the liquid must be electrically insulated (e.g., by using mineral oil) to avoid short circuits. Moreover, the liquid cooling system requires high leak-tightness. Other important considerations include mechanical strength, vibration resistance, and lifespan requirements.

Water cooling is currently the preferred solution for many electric passenger vehicles. Typical products include BMW i3, Tesla, General Motors Volt, BMW Brilliance Automotive NEV, and Geely Vision EV.

The water cooling test platform for new energy battery cooling systems (liquid cooling and water cooling) is mainly used for stability testing of new energy vehicle cooling systems, such as the cooling system of electric drives, motors, gearboxes, and charging stations. This includes constant temperature, constant pressure, constant current thermal testing (from 5 to 85℃), high and low-temperature operation testing (from -40 to 150℃), motor cooling water system testing (from 5 to 30℃), and other cooling tests.

Scope of Application:

Electric vehicles, hybrid vehicles, aerospace, and scientific research.

Test Items:

1.Test the head and flow rate of the water pump to obtain the flow rate and head characteristic curve of the pump;

2.Test the flow rate of water pumps during the actual usage of cars;

3.Test the cooling characteristics of radiators to obtain the radiator’s cooling characteristics;

4.Output temperature characteristic curves for various typical positions;

Image of Water Cooling Testing Equipment:

Temperature Range: -40°C to +150°C