From the point of view of reliability, the manufacturing reliability of Tesla 18650 cylindrical battery and the reliability of its internal fuses will be evaluated. Tesla's battery pack is essentially not low-cost. This is because the cost of 18650 batteries is relatively low, but in order to ensure the cascade of small batteries, a lot of security considerations have to be paid. The connection of so many fuses may be very difficult for large-scale production. Toyota has great strength in new energy vehicles, but after its electric car plan suffered serious setbacks, there were few attempts to build large-capacity batteries. Essentially, its plug-in Prius is more inclined to hybrid cars.
Summarize the characteristics of this approach:
1. Battery packs can be very compact, with almost no space in the middle.
2. Shock resistance and shock resistance are better. Shock absorption buffer materials can be added between CELLs.
3. Converting the heat dissipation process to heating process ensures the possibility of lithium battery operation at low temperature.
4. Ensure the uniformity of heat dissipation of CELL battery.
5. The cost is relatively high, mainly in the price of high-pressure pumps and polymer batteries, both of which have great room for price reduction.
6. Safety, the safety of polymer battery itself is easy to manage.
The whole heat dissipation system has more systematic control requirements, especially for batteries, which need different heat dissipation control algorithms like thermal insulation equipment to ensure the temperature uniformity of the cells within the appropriate temperature range. In the process of analysis, I think it may take several steps to get a simple set of design results:
1. Through the working condition of the whole vehicle, the working condition of battery pack which needs to be discharged and charged is estimated.
2. Using simulation to verify the above conditions;
3. Estimate and deduce the heat production of battery pack under discharge and charging conditions.
4. Consider the choice of the system (liquid cooling and air cooling); Note: In fact, further subdivision is needed. Refer to HEV Battery Heat Generation and Heat Dissipation Consideration.
5. Consider the heat dissipation condition of single battery with normal value.
6. Designing the heat sink or clearance under the given heat dissipation conditions (liquid cooling is the inlet water pressure and temperature, air cooling is the power of the fan and the temperature control of the air at the inlet);
7. The simulation results are obtained by the fluid design software.