how to start a battery manufacturing business

The battery production and manufacturing business mainly has the following four links:
1. How is a cell born?
A cell is the smallest unit of a battery system. Multiple cells form a module, and multiple modules form a battery pack, which is the basic structure of a vehicle power battery. The battery is like a container for storing electrical energy. How much capacity it can store is determined by the amount of active material loaded on the positive electrode and negative electrode. The design of the positive and negative electrode pads needs to be tailored according to different models. The gram capacity of positive and negative materials, the ratio of active materials, the thickness of the pole piece, and the compaction density are also crucial to the capacity.
Slurrying of active materials - stirring process
Stirring is to stir the active material into a slurry through a vacuum mixer. This is the first process of battery production. The quality of this process will directly affect the quality of the battery and the qualified rate of finished products. Moreover, the process flow of this process is complex, and there are higher requirements on the ratio of raw materials, mixing steps, mixing time, etc.
What is stirring here is the active material of the battery.

In addition, in the process of stirring, dust needs to be strictly controlled to prevent dust from affecting the consistency of batteries. In the production workshop of CATL, the level of dust control is equivalent to that of pharmaceuticals.

Coating the stirred slurry on the copper foil - coating process

This process is to evenly spread the slurry that has been stirred after the previous process to the top and bottom of the 4,000-meter-long copper foil at a speed of 80 meters per minute. The copper foil before coating is only 6 microns thick, which can be described as "thin as silkworm wings".

Coating is very important, and it is necessary to ensure that the thickness and weight of the pole pieces are consistent, otherwise it will affect the consistency of the battery. Coating must also ensure that no particles, debris, dust, etc. are mixed into the pole pieces. Otherwise, the battery will be discharged too quickly, and even a safety hazard may occur.

Press the negative electrode material on the copper foil and then cut it - cold pressing and pre-slicing

In the rolling workshop, the pole pieces attached with the positive and negative materials are rolled by rollers. On the one hand, the coated materials are made tighter, the energy density is increased, and the thickness consistency is ensured. On the other hand, the dust will be further controlled. and humidity.

The cold-pressed pole pieces are cut according to the size of the battery to be produced, and the generation of burrs (the burrs here can only be seen clearly under the microscope) are fully controlled. The purpose of this is to avoid the burrs piercing the diaphragm and causing serious security risks.

Cut out the small ears of the positive and negative electrodes on the battery - die-cutting and slitting of the polar ears

The tab die-cutting process is to use a die-cutting machine to form the conductive tabs for the cell. We know that the battery is divided into positive and negative poles. The pole ear is the metal conductor that leads the positive and negative poles from the battery core. In layman's terms, the ears of the positive and negative poles of the battery are the contact points during charging and discharging.
The next slitting process is to slit the battery pole pieces with a cutter.
Complete the prototype of the battery core - winding process
Here, the positive electrode sheet, negative electrode sheet, and separator of the battery are combined into a bare cell by winding. The advanced CCD visual inspection equipment can realize automatic detection and automatic deviation correction to ensure that the cell pole pieces are not in place.

With the assistance of CCD visual inspection equipment, CATL's battery production workshop is one of the most automated battery production workshops in the world.

Moisture removal and electrolyte injection - baking and injection

Moisture is the enemy of the battery system. The battery baking process is to make the internal moisture of the battery meet the standard and ensure that the battery has good performance throughout its life cycle.

Liquid injection is to inject electrolyte into the cell. The electrolyte is like the blood flowing in the body of the battery, and the exchange of energy is the exchange of charged ions. These charged ions are transported from the electrolyte to the other electrode to complete the charge and discharge process. The injection amount of electrolyte is the key. If the injection amount of electrolyte is too large, it will cause the battery to heat up or even fail directly. If the injection amount is too small, it will affect the cyclability of the battery.

The process of cell activation - formation

Formation is the process of activating the battery cells after injection, and the chemical reaction occurs inside the battery cells through charging and discharging to form an SEI film (SEI film: it is the electrolyte and the negative electrode material on the solid-liquid phase layer when the lithium battery is cycled for the first time. A reaction occurs, so a passivation film will be formed, just like a mask is plated on the cell.), to ensure the safety, reliability and long cycle life of the subsequent cell during the charge-discharge cycle. To activate the performance of the cell, it must go through a series of "physical examination processes" such as X-ray monitoring, insulation monitoring, welding monitoring, and capacity testing.

The formation process also includes the second injection of electrolyte after "activating" the cell, weighing, welding of the liquid injection port, and air tightness testing; self-discharge test high-temperature aging and standing to ensure product performance.
All manufactured cells have a separate QR code, which records the date of birth, manufacturing environment, performance parameters, etc. A robust traceability system can keep any information on file. If there is an abnormality, the production information can be retrieved at any time; at the same time, these big data can provide data support for the subsequent improvement design in a targeted manner.
2. Let the cells no longer "streak" battery pack production process

A single cell cannot be used, and it can only be used directly by combining many cells together with a protective circuit and a protective shell. This is called a battery module.

The battery module (module) is composed of many cells. It is necessary to pass strict screening, assemble the cells with good consistency into a modular battery module according to the precise design, and install a single battery monitoring and management device. CATL's fully automated production line for modules is completed by more than a dozen precision robots. In addition, each module has its own fixed identification code, and the whole process can be traced if there is a problem.
The production process from a simple cell to a battery pack is also quite complicated, requiring multiple processes, which is not as simple as the manufacturing process of a cell.

Feeding

The battery is transferred to the designated position, and the robot automatically grabs it and sends it into the module assembly line.

Give the cell a bath - plasma cleaning process

Clean the surface of each cell (CATL Ningde era uses plasma treatment technology to ensure cleanliness). Ion cleaning is used here to ensure that the contaminants in the process do not adhere to the bottom of the cell.
Why use plasma cleaning technology? The reason is that plasma cleaning technology is the most thorough stripping cleaning method among the cleaning methods. Its biggest advantage is that there is no waste liquid after cleaning. Processing, can achieve overall and partial cleaning as well as complex structures.
Combine the cells - glue the cells
Before the cell is assembled, the surface needs to be coated with glue. In addition to fixing, the function of gluing can also serve the purpose of insulation and heat dissipation. CATL Ningde era adopts the most advanced high-precision gluing equipment in the world and the cooperation of manipulators. It can apply gluing according to the set trajectory, and at the same time monitor the gluing quality in real time to ensure the gluing quality, and further improve the consistency of each group of different battery modules. sex.
Build a home for the cell - welding of the end plate and the side plate
The battery modules are mostly welded by aluminum end plates and side plates, which are laminated and welded by robots.
Wire Harness Isolation Board Assembly
After the welding monitoring system accurately locates the welding position, it binds the wire harness isolation board material barcode to the MES production scheduling management system, and generates a separate code for traceability. After coding, the wire harness isolation board is automatically loaded into the module by the manipulator.
Complete the series and parallel connection of the battery - laser welding
Through automatic laser welding, the connection between the pole and the connecting piece is completed, and the battery is connected in series and parallel.
An important level before going offline - offline testing
Check the full performance of the module before going offline, including module voltage/resistance, battery cell voltage, withstand voltage test, and insulation resistance test. The standardized module design principle can be customized to match different models, and each module can also be installed in the best suitable space and predetermined position in the car.
Each battery pack contains several battery cells, which are integrated with connectors, controllers and cooling systems, and are packaged in an aluminum casing. It is automatically tightened by bolts and connected by electrical connectors. Even if a fault occurs, only a single module needs to be replaced, and the entire battery pack does not need to be replaced. The maintenance workload and danger are greatly reduced. To replace the module, only the cooling system needs to be removed solution, and does not involve other components.
3. The ultimate test of the battery pack Battery pack safety test
In fact, electric vehicles must use various methods from the initial design stage to ensure maximum safety. However, no matter how perfect a design is, it has to be tested in practice. In the Ningde era, only battery products that have successfully passed these tests can be released for use.
590 degrees Celsius fire test
What is the concept of burning a battery at 590 degrees Celsius? We know that the ground temperature of Venus is 464 degrees Celsius. At such a high temperature, metal materials such as lead and zinc have already melted. However, the battery pack has to "survive" the challenge at such high temperature.
In terms of safety performance, the national standard is that the external combustion is 130 seconds, and the battery will not catch fire or explode. However, as an industry leader, CATL Ningde era has higher requirements. It not only achieves the national standard that the battery can still work normally after 130 seconds of external combustion, but also reaches the national standard of continuous combustion at 590 degrees Celsius for 1 hour. Still no explosion hazard.
21 hours of continuous vibration test
In daily car use, it is inevitable to pass some bumpy roads, and the vibration generated by the battery may lead to poor fixing of battery products with poor quality, loose parts, and even shell rupture, which may eventually lead to safety failure.
So we need to simulate the impact of vehicle vibration on the battery pack. 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 charge and discharge machine 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 realistically simulates the situation when a real vehicle is used.
A shaking table with a thrust of 20 tons in the Ningde era was used to simulate the bumpy road conditions that the battery pack would encounter in actual use, but its vibration was more intense than the actual road conditions. In the test, the battery pack was vibrated 200 times a second, and the cell module was vibrated 2,000 times. What's more severe is that the battery pack needs to vibrate continuously for 21 hours under the environmental conditions of -30°C to 60°C, which can effectively simulate the driving fatigue of hundreds of thousands of kilometers.
Shock test with acceleration up to 100G
Similar to the vibration test, the shock test is used to test the stability of the mechanical structure of the battery pack. It simulates the impact of the instantaneous bump on the battery pack structure when the vehicle passes through the roadblock. In addition, there is a 1 in 10,000 chance that the battery will fall during the process of replacing the battery. The so-called "don't be afraid of 10,000 is afraid of the unexpected. CATL Ningde era will conduct a free fall test of the battery from a height of 1 meter, and ensure that all functions are still normal.
In the impact test of the Ningde era, the maximum acceleration can be as high as 100G. It should be known that the maximum acceleration that the average person's heart can withstand is 50G. The current record, the acceleration limit that the human body can withstand is about 40G. Under such a strong acceleration shock, the battery pack still operates normally.
The closest crush test to a real accident
The extrusion test is used to simulate the situation that the battery is squeezed in a traffic accident. As the degree of deformation of the battery increases, the positive and negative current collectors will be torn first. A very large current is generated at the short-circuit point, and the heat is released in a concentrated manner, causing the temperature of the short-circuit point to rise sharply, so it is easy to cause thermal runaway, which in turn can cause fire or explosion.
In the extrusion test, it was found that the outer casing of the battery pack was obviously deformed, the internal structure was damaged, the cell was punctured by internal components, and a high-voltage short circuit occurred, resulting in thermal runaway. The pass criteria for the crush test are generally no fire and no explosion. The battery products of the Ningde era can even continue to work normally under the condition of being squeezed and deformed.
In the extrusion test of the Ningde era, the force applied to the battery pack was ten tons. The weight of the 12-meter bus is 7 tons, and the weight of passengers and luggage is close to 10 tons, which means that this can at least simulate the squeeze of a 12-meter bus when it hits.
Since then, after countless complicated processing techniques and testing and testing procedures, a finished vehicle battery unit printed with CATL LOGO was finally born, but this is not the end of the quality control, in order to control the daily use. All finished batteries and cells have their own unique codes. If that battery or even that cell fails in the future, it can be traced back to that production line or even that batch of raw materials. For a dangerous product like a battery, quality is always the most important part.
At present, CATL has formed a complete chain system from the mining of raw materials to the later recovery. The cooperative relationship with international companies such as BMW and Mercedes-Benz has once again proved the advantages of its products. Product stability and good reputation are the keys to winning, but in the new energy industry, if you cannot advance, you will retreat. In the future, it is necessary to continuously launch market-competitive products in order to always stand at the top of the industry.
4. Sales, transportation, installation and maintenance of finished batteries
For the battery sales business, look for major battery demand companies, negotiate, produce samples, and then mass produce. Batteries are mostly customized products. After customization, delivery needs to be transported. In the transportation industry, lithium-ion batteries have always been listed as dangerous goods, not only for themselves, but also for equipment installed with lithium-ion batteries. Due to safety concerns, the transportation method of lithium-ion batteries is very strict.
The strict requirements for all lithium-ion battery products are to prevent the internal or external short circuit of the battery during transportation, thereby causing fire, and there are the following regulations.
1. The outer packaging should be labeled with 9 types of dangerous goods, and the product name, correct operation, information consultation telephone number, etc.
2. Lithium-ion batteries need to pass a 1.2-meter drop packaging test before being transported.
3. The lithium-ion battery equipment needs to be fixed in the package to prevent it from moving in the package.
4. The design of the outer packaging must be sturdy to ensure that it can be prevented from bursting under normal transportation, and must have a waterproof function.
5. The weight of a single package depends on the means of transportation.