The article is to introduce the principles and installation requirements of the battery thermal management system (BTMS battery). For better understanding, the definition, necessity and design requirements of Battery Thermal Management System (BTMS) are also presented.
Battery thermal management system is a system that keeps the electric vehicle power battery within a suitable temperature range. Its existence increases the service life of the battery and ensures the safety and driving mileage of the entire vehicle. Its abbreviation is BTMS. But BTMS is often used to refer to betamethasone or emulsifying wax. To differentiate, I will refer to it as a BTMS battery below.
The main principle of cooling is that the coolant contacts the battery core through the water pipe. Currently, a mixed solution of water and ethylene glycol is mostly used. The liquid cooling BTMS battery system couples a heat exchanger to the refrigeration cycle to remove heat from the battery through the refrigerant. Its core components are the compressor, heat exchanger and water pump. As the starting point of refrigeration power, the compressor determines the heat exchange capacity of the entire system. The heat exchanger plays a role in exchanging refrigerant and coolant. The amount of heat exchanged directly determines the temperature of the coolant. The water pump determines the flow rate of the coolant in the pipeline. The faster the flow rate, the better the heat exchange performance, and vice versa.
BTMS battery is connected to high-voltage batteries, and the voltage is usually above 280v. Be careful and pay attention to personal safety during installation, commissioning and maintenance.
1. The expansion water tank must be located at the highest point of the entire system. And an overflow pipe must be arranged. The overflow pipe is a device that can instantly warn the water level. It is very important for the safe use of the BTMS battery. The exhaust pipe of the expansion water tank has a smooth passage. The pipe cannot have a curved design, otherwise water will easily accumulate in the curved part, which will lead to failure. The expansion water tank water pipe runs smoothly and ensures that the water line can continue to flow downwards during operation.
2. BTMS battery should be installed in the direction required by the "drawings" and random rotation is strictly prohibited. It must be ensured that the axis of the compressor is perpendicular to the direction of vehicle travel.
3. The driving environment of vehicles is different, and there is often water wading. The installation location for side-mounted BTMS battery system is usually on the chassis. It cannot operate in water, so it must exceed the vehicle's wading height.
1. The main pipe of the BTMS battery should be smooth and not deformed. At the same time, avoid too many curves and undulations. Too much will cause excessive flow resistance and affect system flow.Unsmooth and efficient flow will lead to reduced cooling effect.
2. The exhaust tee-water injection tee-water pump water inlet (battery cooling module water inlet) should be arranged and connected in a pipeline from high to low. The reason for this is to facilitate the removal of air.
3. Ensure that the air inlet and outlet of the battery thermal management system are smooth. If the air inlet and outlet are not clear, it can easily lead to poor cooling effect. In severe cases, it will cause a high-voltage alarm and stop working. Secondly, do a good job of waterproof sealing to ensure that there is no cross-wind phenomenon.
If the charging temperature of the mobile phone is too high, it will explode, and if the temperature is too low, it will shut down. The same applies to power batteries. Temperature also has a great impact on its performance, lifespan and safety.
At low temperatures, the internal resistance of lithium-ion batteries increases and the capacity decreases. In extreme cases, the electrolyte freezes and the battery cannot be discharged. This will cause the electric vehicle's power output performance to be attenuated and its driving range to be reduced. At high temperatures, chemical reactions inside the battery accelerate, which also causes the internal resistance of the battery to increase rapidly. Battery capacity decreases. Decomposition of the electrolyte and oxidation of the electrode can lead to the deterioration of the electrode material. These changes can reduce battery cycle life and capacity.
As the main power source of electric vehicle, power batteries are of great importance to EV. In order to increase the cruising range, EV need to arrange as many batteries as possible in a certain space. Therefore, the space for battery cooling system in EV is very limited. The battery generates a large amount of heat during vehicle operation, this heat accumulates in a relatively small space. Due to the dense stacking of cells in the battery pack, the temperature inconsistency between cells is aggravated. This will cause the battery's charging and discharging efficiency to decrease and affect the battery's power. In severe cases, it can also lead to thermal runaway, affecting the safety of the battery system and the entire vehicle system.
BTMS is one of the important functions in BMS. It is mainly to allow the battery pack to always work within a suitable temperature range. Keep your battery pack in optimal working condition. The BMS is the commander. It first collects the battery ambient temperature from the BTMS battery system. Then cooling/heating commands are issued to the BTMS according to the CAN control module algorithm. This is a process of real-time monitoring and regulation. BMS will calculate and adjust fan speed, coolant flow, etc. based on temperature changes and target temperatures. This helps conserve limited power while keeping the battery operating within the appropriate temperature range. This enables optimal power output and input, maximum usable energy, and longest cycle life for electric vehicles.
Battery thermal management system (BTMS) involves the interaction with multiple systems, so engineers need to master a lot of knowledge and abilities. It's not something that ordinary engineers can do. The following are the most basic requirements:
1. Knowledge of thermodynamics: You need to understand the basic principles of thermodynamics, including heat transfer, mass transfer, thermodynamics, etc.
2. Mechanical design knowledge: Basic knowledge of mechanical design is required, including mechanical drawing, material mechanics, manufacturing processes, etc.
3. Electronic technology knowledge: You need to understand the basic principles of batteries and electronic technology knowledge, including battery charge and discharge principles, battery management systems, etc.
4. Software skills: You need to master relevant software tools, including CAD software, CFD simulation software, data analysis software, etc. Among them, CAD software is used to design the structure and components of the thermal management system, simulation software is used to simulate and analyze the thermal behavior of the battery and the working performance of the thermal management system, and data analysis software is used to process and analyze experimental data.
5. Experimental skills: Experimental skills are required, including experimental design, experimental operation, experimental data analysis, etc.
Busthermo (the new brand of TKT HVAC) has started research and manufacturing in this field in 2010. We have very rich design experience and mature product solutions. Customers are welcome to leave messages for consultation or Email:md@tkt-hvac.com. In addition, we provide customized services. The customized BTMS battery system has better performance and more suitable size.
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