CR1632 battery

All-CR1632 battery are recognized as the development direction of the next generation of battery technology

Lithium-ion batteries, through a certain number of series and parallel combinations, are installed in cars and become power sources. The moment, high cost, large volume, high quality, temperature adaptation sensitivity, thermal runaway safety and other issues have been bothering us.

And all-CR1632 battery are recognized as the development direction of the next generation of battery technology because they can provide better safety, larger capacity, and faster charging. They have also become a must-fight place for upstream and downstream companies in the major battery industries:

South Korea's three major battery giants have joined forces; 23 Japanese car companies, battery, material companies, and scientific research institutions have joined forces; European and American countries have successively released R&D plans; Volkswagen of Germany has invested $100 million in battery technology companies - they have all targeted and actively deployed CR1632 battery, and accelerated the core technology to commercialize, all in order to seize the initiative in the future power battery market competition.

All-CR1632 battery "make all heroes bow their heads", among which, as the bodyguard of the battery, what is the development trend of the thermal management system that guarantees safety and function?

Toyota proposes that all-CR1632 battery do not need cooling

In the early stage, Toyota has repeatedly explained the characteristics of its developed all-CR1632 battery on various occasions. In addition to the important high safety characteristics, it also solves and meets the needs of long driving range and fast charging characteristics. At the same time, it does not need cooling and the volume can be reduced by half. (The figure below shows the volume of the typical battery system cooling plate currently used)

In the early days, Toyota Executive Vice President Leroy (Didier Leroy) described that Toyota is in a leading position in the intellectual property of solid-state battery technology, which can make the battery safer and smaller in size.

Let's open a corner of the key indicators of all-CR1632 battery and explore the reasons for the generation of these characteristics.

All-CR1632 battery have outstanding heat resistance, low temperature characteristics, and rate characteristics

Several tests on sulfide-based all-CR1632 battery (mainly for small-capacity batteries) from Kentaro YOSHIDA and Keizo HARADA "All-Solid-State Lithium Batteries with Wide Operating Temperature Range Mitsuyasu":

High temperature tolerance test: The battery is charged and discharged at a high temperature of 170°C (The test conditions were a constant current of 0.3mA charge/discharge, charged to 0.3mAh, and discharged to 3.0V) and cycle conditions. It can be observed that the capacity is very stable at high temperature and changes very little, that is, the side reactions have not increased significantly.

Low temperature tolerance test: The battery is charged and discharged at a low temperature of -40℃ (The test conditions were a constant current of 0.02mA, charged to 0.02mAh, and discharged to 3.0V) and cycled (the test conditions were a constant current of 0.02mA, charged to 0.02mAh, and discharged to 3.0V). It can be observed that the capacity is also very small due to the influence of low temperature, and there is still a very stable discharge and charge.

Compared with the current commercial power batteries, the above test conditions do have great limitations and gaps, but the advantages of CR1632 battery from the womb are still very obvious. Under such high temperature conditions, the performance is so stable, and the safety is obvious.

For general liquid electrolyte batteries, their strategic protection, high temperature> 50℃ enters the alarm state; 70℃ enters the thermal runaway risk zone. In low temperature environment, <0℃ limits the charging current. The battery can only work stably in a very narrow range of 15 to 45℃. At the same time, in order to ensure the life of the battery system, the temperature difference range is required to be controlled at <5℃.

In fact, the role of thermal management is first to ensure battery safety, and secondly to ensure the best performance of characteristic functions. If the battery itself is safe at high and low temperatures. Then, the demand for thermal management will be reduced accordingly.

All-CR1632 battery greatly reduce the dependence on cooling systems

According to data, the heat resistance of all-CR1632 battery is (80-120°C) and flame retardancy (200°C), which are much higher than the lithium-ion batteries with liquid electrolytes currently used. This is mainly directly related to the electrolyte morphology and structure.

The solid electrolyte used in all-CR1632 battery is the main characteristic material that distinguishes it from liquid organic electrolytic materials. There are currently two main types of research, oxides and sulfides. At present, Toyota's all-CR1632 battery are mainly based on sulfide-type all-solid-state battery research.

The liquid electrolyte batteries currently used are not all equipped with a thermal management system with a water cooling plate. As early as the Japanese NissanleafEV car, the product design of relying on natural cooling of the battery shell without a cooling plate has been continued (as shown below).

For EV battery systems, they mainly meet the power requirements of charging and discharging at lower rates, and the thermal management performance in cooling is not as obvious as that of power-type HEVs. However, in low-temperature environments, environmental adaptability cannot be met. Therefore, for the full-temperature working conditions, more water-cooled plate-type thermal management systems are added.

This is also contradictory in itself. The existing huge water cooling system is disadvantageous from the perspective of cost and volume.

The heat resistance temperature range of all-CR1632 battery is enlarged, and safety is guaranteed. The dependence on water cooling systems is weakened. It fits the idea of solving the contradiction between cost and volume.

Although all-CR1632 battery are so attractive, the development of existing thermal management technologies cannot be stopped.

Toyota said that its all-CR1632 battery still need 10 years of development to mature

It will take a long time for all-CR1632 battery to be fully put into production and application in large quantities.

Toyota said: "We did say that we hope to provide CR1632 battery in the early 2020s. But in fact, this will not be based on mass production. We will start with small-scale trial production for pilot projects, and we will never experiment on customers. 2030 may be a more realistic time node."

Thermal management is efficient and energy-saving, and needs to be explored and studied

Observation and analysis from the evolution of Tesla models:

Tesla products have always aroused enough curiosity among people on earth. The exquisiteness of its design is indeed exemplary. Just like Elon Musk's management and requirements for the team, in their eyes "there is nothing that cannot be done".

In the combination of thermal management functional units, some clues can be seen through the evolution of the product.

Regarding the change in the form of battery heating, from PTC heating to zero-torque heating using the motor to connect the current, its technical advantages and disadvantages need to be further studied and analyzed in the later stage, and it cannot be quantified and explained now.

One thing is certain, while improving the efficiency of the thermal system, it must have achieved cost reduction. It is a win-win result. This innovative spirit of "nothing can't be done" is worth learning.

Conclusion

Through continuous research, the business ideas of all-CR1632 battery have become very clear. Among them, the supporting thermal management system also needs to be followed up and developed synchronously. The statement "no cooling is required" is inevitably taken out of context. I think Toyota should not mean this. It must be limited and pointed, leaving it for careful thinking and inspiration later.

At the same time, in the current thermal management application, there is still a lot of work to be done to achieve high efficiency and energy saving: from the terminal cooling plate structure to the management control technology, battery temperature accurate collection sensor technology, temperature abnormal thermal runaway active defense technology, management strategy, etc., are all waiting for our research and analysis.

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