Battery Cooling Solutions
- Categories:New Energy Vehicle Battery Cooling Application Solution
- Time of issue:2020-06-18 00:00:00
Importance of thermal management systems
Heat-related issues of the battery are key factors in determining its performance, safety, life and cost of use. First of all, the temperature level of lithium-ion batteries directly affects their energy and power performance in use. When the temperature is low, the available capacity of the battery will rapidly decay. It may cause instantaneous over-charging of voltage, resulting in internal lithium precipitation and subsequent short circuit. Secondly, the heat-related problems of lithium-ion batteries directly affect the safety of the battery. Defects in the manufacturing process or improper operation in the use process may cause local overheating of the battery, which in turn may cause chain exothermic reaction. In the end, it causes serious thermal runaway events such as smoke, fire and even explosion, which threatens the lives of vehicle drivers and passengers. In addition, the working or storage temperature of the lithium-ion battery affects its service life. The appropriate temperature of the battery is about 10 ~ 30 ℃ between, too high or too low temperature will cause the battery life faster decay. The large size of the power battery makes its surface area to volume ratio decrease relatively, the internal heat of the battery is not easy to dissipate, and it is more likely that the internal heat will appear in the battery. Uneven temperatures and high local temperature rise, which further accelerates battery degradation, shortens battery life and increases total user ownership. Cost.
The battery thermal management system is one of the key technologies to deal with the heat-related problems of batteries and to ensure the performance, safety and life of power batteries. . The main functions of the thermal management system include.
1) Effectively dissipate heat when the battery temperature is high to prevent thermal runaway accidents;
2) Preheat the battery when the temperature is low to raise the temperature of the battery and ensure the charging and discharging performance and safety under low temperature;
3) Reduce the temperature difference within the battery pack, inhibit the formation of local hot zones, prevent the battery from decaying too quickly at high temperature, and reduce the overall life of the battery pack.
Overview of new energy battery pack
Battery packs from major international brand companies show us products that are placed in the chassis between the front and rear axles and can weigh up to Around 900 kg. This results in a low center of gravity of the chassis, which is very conducive to the high-speed stability of the vehicle. The battery pack occupies almost the entire chassis of the vehicle, but the battery pack does not act as the main body of the load bearing, it has a reinforcing rib and a load bearing frame. Protection, greatly reducing the risk of explosion in the event of a collision.
Disassembly of the battery panel and connection details
The surface of the battery pack is not only protected by a plastic film, but also by a shield of fireproof material under the plastic film. Beneath the shield is the battery pack. The shield is bolted to the battery pack frame and the connection is filled with sealing adhesive. The exterior looks like the battery pack is well protected.
The Tesla Model S battery pack plate appears to be very tall. Its battery panel is made up of 16 battery packs in series and each battery pack is formed by 444 lithium-ion batteries in parallel every 74 cells. So the Tesla Model S battery panel consists of 7,104 lithium 18650 batteries.
In addition to the battery packs, the battery plates contain, at most, "coolant" lines. Each battery pack requires a certain amount of "coolant" to flow through it. Although there is no active flow of "coolant" driven by a pump, all the lines are connected throughout the panel and the "coolant" can be Thermal expansion and contraction for a certain range of flow.
Battery Management System (BMS for short) is a system for Battery pack safety monitoring and effective management and improve the efficiency of battery use device. For electric vehicles, the effective control of battery pack charging and discharging by this system can increase the mileage, extend the service life, and improve the efficiency of the battery pack. The purpose of the battery management system is to reduce operating costs and to ensure the safety and reliability of battery pack applications.
The main functions of the battery management system include data collection, battery status calculation, energy management, thermal management, safety management, balancing control, and battery management. Communication functions, etc. As can be seen from the circuit diagram, the battery management system is Tesla's own research and development, with a high degree of intellectual property rights of the core technology. The system can handle the charging and discharging as well as the heating problem by itself. It is believed that it is difficult for domestic manufacturers to copy it.
Disassembling the Tesla Model S on its own lets us know more details. the number of 18650's is determined by the total capacity of the battery plate. Aluminum tubes and "coolant" are used to even out the heat generation of the battery, and the complex processing of the battery management system BMS makes the battery more efficient. Perfect charging and discharging.
Overall, the Model S battery is pretty well protected, the internals are appropriately well-designed, and the battery management system is fairly Fine. I believe that domestic brands want to copycat have a lot of difficulties.
Domestic Mo brand battery pack details
XX Technology Thermal Solution: to ensure more stable performance of your car battery and make the battery pack life cycle longer, so that your battery pack to perform at its best.
Heat dissipation principle：the battery produces a lot of heat when working, the heat is transferred to the water-cooling tube by the thermal conductive silicone film, and the water-cooling tube is then transferred to the coolant, the liquid in the water-cooling tube will flow in the battery pack and take the heat away.
Heat dissipation principle of battery thermal management system of an automobile manufacturer
Heat dissipation principle：The fan is used to actively dissipate heat, and the fan supplies air, which blows towards the runner of the battery and takes away the heat inside the battery pack.
Heat dissipation principle：Since the temperature difference between the battery pack is not controlled within 5℃, a piece of heat-conducting silicone film is pasted on the top and bottom of the battery pack, and the silicone film directs the temperature to the aluminum shell outside, so that the temperature difference between the whole battery module is controlled within 5℃, which meets the design requirements of the battery pack and makes the life of the battery pack longer and the performance more stable in the driving process.
Heat dissipation principle：the battery pack adopts passive heat dissipation, a piece of heat-conducting silicone film is pasted between the battery pack and the aluminum radiator, and the silicone film will transfer the temperature to the aluminum radiator, and then the aluminum radiator will exchange heat with the air.
Our company provides battery thermal management system heat dissipation principle
Heat dissipation principle：The battery pack adopts passive heat dissipation, a sandwich material folded by (graphite heat sink + aerogel heat sink + graphite heat sink) is pasted between the battery pack and aluminum radiator as ⊥ structure type, and the temperature will be transferred to the aluminum radiator, and the mutual heat energy will not be exchanged in the heat conduction between the battery pack, but will be directly conducted to the aluminum radiator and then exchanged with the air.
There are two kinds of adhesive used in new energy battery, the first one is high temperature adhesive paper, silica gel, which is mainly used for insulation and the second one is adhesive, such as double-sided adhesive, quick-drying adhesive, etc., mainly used for fixing between batteries.
We can provide the following products: lithium battery termination tape, digital tape, brown high temperature tape, sealing and insulation tape, Mylar tape, OPP tape, battery fixed tape, masking paper tape, Teflon tape, PC/PET/PP adhesive.
Mainly used in aluminum battery manufacturing, soft pack battery manufacturing, steel case battery manufacturing and assembly field.
PC backing：3M9448 3M467
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