The rise of contemporary Ampere Technology Co., Ltd. is phenomenal, of course, this is inseparable from its elaborate lithium battery production process. In this issue, we will show you the super factory of Contemporary Ampere Technology Co., Ltd..
First, the birth of the battery
First, let's look at the battery production line. This is the first world-class automatic production line in China, where BMW X 1 and brand-new 5-series batteries were born.
All personnel entering the workshop must wear clean clothes, hats and masks. After completion, they need to pass through the spray booth for dust removal at 360 degrees without dead ends.
Temperature control, humidity control and dust-free factory can rival the manufacturing environment of semiconductor microelectronics.
Busy RGV automatically carries materials and loads and unloads materials for equipment according to the set track.
Lonely manipulator automatically unloads the disk and encodes it.
With the help of high-tech robots, central control system, online inspection equipment and information tracing system, catl's production line can realize "visualization of production data", "transparency of production process" and "unmanned production site".
A battery cell is the smallest unit of a battery system. M batteries form a module and n modules form a battery pack, which is the basic structure of vehicle power batteries. A battery is like a container for storing electric energy, and the capacity it can store depends on the amount of active substances loaded on the positive and negative plates.
1 stirring
Stirring is to evenly mix the anode and cathode solid-state battery materials, then add the solvent and stir with a vacuum blender to form a uniform slurry.
2 coating
The mixed active materials are evenly coated on the upper and lower surfaces of a 4000m-long copper foil at a speed of 80m per minute. The copper foil before coating is as thin as cicada's wings, only 6 microns thick. Coating is very important, so it is necessary to ensure that the thickness and weight of the pole piece are consistent, otherwise it will affect the consistency of the battery. The coating must also be free of particles, sundries, dust, etc. Is mixed into the pole piece. Otherwise, the battery will self-discharge too fast, and even there will be safety hazards.
3 cold pressing and pre-cutting
The roller device compacts the coated pole piece to a predetermined thickness and density.
Punching and stripping of 4-pole lug
Here, the conductive tabs of the battery cells are formed by die cutting with a die cutter. Ear is the ear on the battery head, which is the connection point between the positive and negative ears of the battery when charging and discharging. Then, use a cutting machine to cut the pole piece.
5 winding
A positive electrode plate, a negative electrode plate and a separator of a battery cell are combined in a winding manner to form a bare battery cell. Advanced CCD can realize automatic detection and automatic deviation correction to ensure that the battery pole piece is not in place.
6 assembly
The wound bare cells will be automatically sorted and paired, and then go through the processes of welding, welding folding, top bracket assembly, hot-melt polyester film, shell insertion and shell welding. At this time, the bare cell has a hard shell.
7 Baking and liquid injection
The baking process of the battery is to make the internal moisture of the battery reach the standard and ensure the good performance of the battery in the whole life cycle. Liquid injection is to inject electrolyte into the baked battery cell. Electrolyte is like blood flowing in the battery, and the exchange of energy is the exchange of charged ions. These charged ions are transported from the electrolyte to another electrode to complete the charging and discharging process.
8 Chenghua
Formation is the process of activating the battery after liquid injection. SEI film is formed by chemical reaction inside the battery through charging and discharging, which ensures the safety, reliability and long cycle life of the subsequent battery in charging and discharging cycle.
In order to have good performance, the battery cell manufacturing process has to go through a series of "physical examination processes" such as X-ray inspection, welding quality inspection, insulation inspection and capacity test.
After manufacturing, each battery cell has a separate two-dimensional code, which records the manufacturing date, manufacturing environment, performance parameters and so on. A powerful traceability system can record any information. In case of abnormality, production information can be retrieved at any time; At the same time, these big data can provide data support for subsequent improved design.
Second, the module deformation record
A single battery won't work. Only when many batteries are combined together, plus protective circuits and protective cases, can they be used directly. This is called a battery module.
The battery module consists of many battery cells. Through strict screening, the batteries with good consistency are assembled into modular battery modules according to accurate design, and monitoring and management devices for single batteries are installed. CATL's modular automatic production line is completed by more than a dozen precision manipulators. In addition, each module has its own fixed identification code, so the problem can be traced back to the whole process.
The production process from simple battery cells to battery packs is also quite complicated, requiring multiple processes, which is not simpler than the manufacturing process of battery cells.
1 feeding
The battery cell is transported to the designated position, and the manipulator automatically grabs it and sends it to the module assembly line. In the workshop of Contemporary Ampere Technology Co., Ltd., from automatic material handling to equipment feeding, 100% automation has been realized.
Give the battery a bath-plasma cleaning.
Clean the surface of each cell (CATL Contemporary Ampere Technology Co., Ltd. adopts plasma treatment technology to ensure cleanliness). Ion cleaning is used here to ensure that pollutants in the process will not adhere to the bottom of the battery.
Why use plasma cleaning technology? The reason is that plasma cleaning technology is the most thorough stripping cleaning method among cleaning methods. Its biggest advantage is that there is no waste liquid after cleaning, and its biggest feature is that it can handle metals, semiconductors, oxides and most polymer materials well, and can realize overall and local cleaning and cleaning of complex structures.
3 Assemble the battery-stick the battery with glue.
The surface needs to be glued before assembling the battery. The function of gluing is not only fixation, but also insulation.
CATL Contemporary Ampere Technology Co., Ltd. adopts the world's most advanced high-precision gluing equipment and robots to glue according to the set trajectory, and at the same time monitors the gluing quality in real time to ensure the gluing quality and further improve the consistency of each group of different battery modules.
4. Building a battery cell house-welding of end plates and side plates
Most battery modules are welded by aluminum end plates and side plates. After the equipment monitors the assembly parameters (such as length/pressure, etc.). ) Start the welding end/side plate of the welding robot online, ensure the welding quality online 100%, and monitor the welding quality online 100%.
5 Assembly of wire harness isolation plate
After the welding monitoring system accurately locates the welding position, the bar code of the wire harness isolation plate is bound to the MES production scheduling management system to generate a separate code for traceability. After coding, the wire harness isolation plate is automatically loaded into the module through the manipulator.
6. Complete the series-parallel connection-laser welding of the battery.
Through automatic laser welding, the connection between the pole and the connector is completed, and the series and parallel connection of batteries is realized.
7. An important step before going offline-offline testing
Check all the performance of the module before offline, including module voltage/resistance, battery cell voltage, withstand voltage test and insulation resistance test. Standardized module design principles can be customized to match different models, and each module can also be installed in the most suitable space and reserved position in the car.
Third, battery adventure.
Before reassembling, the battery pack needs to go through "81 difficulties" to be repaired. In contemporary Amperex Technology Co., Ltd., these extremely demanding experiments include challenging high temperature fire, extrusion, impact, vibration, seawater immersion, high and low temperature impact and so on. And there are as many as 230 items. In Contemporary Ampere Technology Co., Ltd., only battery products that have been successfully tempered can be released for use.
1 fire test
Metal materials such as lead and zinc have already melted under high-temperature oil and gas fireworks. However, the battery pack must "survive" at such a high temperature. In this extremely dangerous test, the national standard of the industry is external fire 130 seconds, and the battery will not catch fire and explode. But in CATL, everything has the highest requirements. The national standard requires no fire or explosion after external combustion, but CATL challenges the battery to work normally after external combustion 130 seconds. The national standard requires the external combustion time to be 130 seconds. CATL even studied that after continuous combustion 1 hour, the battery still has no danger of explosion. In this case, even aluminum with a melting point of 660℃ has already melted into liquid.
Through such strict fire test, even if there is a fire or vehicle burning, there will be no danger of battery explosion and secondary injury will be avoided.
2 vibration test
The battery vibration caused by the bumpy road surface may lead to the poor quality battery products not being firmly fixed, the parts being loose, the shell being broken, and finally the safety failure. Therefore, the national standard requires vibration testing of power batteries.
The vibration table is used to simulate the bumpy road conditions that the battery pack will encounter in actual use, the environmental box is used to provide different temperature environments, and the charging and discharging motor is used to provide the actual working conditions of charging and discharging. These three parts constitute a vibration test system with temperature and load, which truly simulates the scene when the real vehicle is used.
This is a 20-ton shaking table of contemporary Amperex Technology Co., Ltd., which is used to simulate the bumpy road conditions that the battery pack will encounter in actual use, but its vibration intensity is even stronger than the actual road conditions. In the experiment, the battery pack vibrates 200 times per second and the battery module vibrates 2000 times. When the wings of bees vibrate 400 times per second, we can hear the sound of "buzzing", and the sound made by the battery module vibrating 2000 times per second is very sharp and harsh.
In Contemporary Ampere Technology Co., Ltd., this vibration is challenged not in a few minutes but in a few hours. Here, the battery pack needs to vibrate randomly for 2 1 hour under the environmental conditions of -30℃ to 60℃, which can simulate driving fatigue of hundreds of thousands of kilometers.
3 Accelerated impact test
Similar to the vibration test, the impact test is used to test the stability of the mechanical structure of the battery pack and simulate the impact of instantaneous bumps on the battery pack structure when the vehicle passes through the roadblock.
In the impact test of contemporary Ampere Technology Co., Ltd., the highest acceleration can be as high as 100G. The maximum centripetal acceleration of manned spacecraft is 15G. When the electric bus is hit by a car with a speed of 50 kilometers per hour, the acceleration of the battery pack is about 30G. The maximum acceleration that the average person's heart bears is 50G. At present, the recorded acceleration limit of human body is about 40G. However, under such a strong acceleration impact, the battery pack still operates normally.
4 extrusion test
Squeeze test is used to simulate the battery being squeezed in traffic accidents. When the battery is squeezed, it may be damaged from the outside to the inside, leading to high voltage short circuit, and the battery core is punctured by internal parts and leaked, leading to thermal runaway, which may lead to fire or explosion.
In the extrusion test of Contemporary Ampere Technology Co., Ltd., the force applied to the battery pack is 10 ton. A 2-ton car crashed at a speed of 90km/h, and the impact force was just 10 ton.
As can be seen from the figure, under the extrusion of 10 ton external force, the battery shell made of composite aluminum has been obviously deformed, but the overall structure of the battery pack is complete. Generally speaking, the passing standard of extrusion test is not to catch fire or explode. The battery products of Contemporary Ampere Technology Co., Ltd. can continue to work normally even in the case of extrusion deformation.
Four. Concluding remarks
After that, after numerous complicated processing technologies and testing procedures, a finished battery with CATL logo was finally born. But even so, the quality control of Contemporary Ampere Technology Co., Ltd. is far from over. In order to control the quality in daily use, all finished batteries and batteries have their own unique codes. If a battery or even a battery fails in the future, it can be traced back to related production lines or even related raw materials.
Source /CATL Contemporary Ampere Technology Co., Ltd., Chairman of Lithium Battery Alliance