Lithium iron phosphate (LFP) batteries are lithium-ion batteries that use lithium iron phosphate as the positive electrode material and carbon as the negative electrode material. The LFP battery assembly and production process consists of three main stages: electrode fabrication, cell fabrication, and battery assembly. In the LFP battery assembly and production process, electrode fabrication is the foundation, cell fabrication is the core, and battery assembly directly affects the quality of the finished lithium battery.
I. Assembly Method of Lithium Iron Phosphate Battery
1. Select suitable battery cells. The cell type, voltage, and internal resistance must be matched. Please balance the battery cells before assembly. Cut the electrodes and drill holes.
2. Calculate the distance based on the holes and cut the insulation board.
3. Tighten the screws. Please use flange nuts to prevent the nuts from falling off. Once the screws are tightened and connected, the lithium iron phosphate battery pack will be secured.
4. When connecting and soldering the wires, do not connect an external protection board to avoid accidental burnout of the protection board.
5. Secure the insulating silicone again. This silicone will harden over time.
6. Install the protection board. If you forgot to balance the cells before, this is the last chance before assembling the lithium battery. You can balance them using the balancing wire.
7. Next, use an insulating board to fix the entire lithium iron phosphate battery pack and seal it with nylon tape. Nylon tape is more durable. Please note that we have never used steel casings. Although steel casings are beautiful and sturdy, it is difficult to guarantee the bonding of the cells. Some casings that are not properly treated may scratch the cells and cause leakage, or even cause accidents due to poor insulation.
8. Then encapsulate the battery cell as a whole. Please make sure to secure the battery cell and protection board. Our battery cells have been tested and will still work normally after being dropped from a height of 1 meter.
9. The final packaging is complete, with silicone wires used for both input and output. Because it uses lithium iron phosphate cells, the 48V 20AH lithium battery pack weighs 9 kg, half the weight of a comparable acid battery.
10. The tutorial is complete. After the lithium iron phosphate battery pack was completed, we conducted tests and it meets our requirements.
II. Process Steps of Lithium Iron Phosphate Battery Assembly Technology
1. Battery Material Processing: Some materials used in rechargeable batteries, such as lithium-ion batteries, require special processing. Electrodes should be processed at high speeds to avoid damaging fragile active materials. Special consideration must be given to preventing the formation of precipitates and corrosive gases in the electrolyte.
2. Cam Unit: If a machine is constructed using cylinders or AC servo actuators with a cycle time of less than 1 second, even if it is in good condition when a new machine is installed, it is difficult to synchronize or maintain a stable state over a long period. Furthermore, cylinders reach the end of their travel distance in a short time, resulting in short maintenance cycles. In a cam mechanism in the machine's construction, this problem can be solved because all drives are maintained by a minimal electric motor.
3. Mounting and Base: Establishing a robust mounting and foundation for the machinery is crucial for long-term stability. A well-designed mounting and base can reduce start-up time by minimizing precision deviations in the transmission and handling mechanisms. Typically, the use of aluminum frames is eliminated. A stable foundation is constructed using thick square logs and a robust base built with a can manufacturing process. For various requirements, annealing can be performed, and mounting bases with additional precision can be used.
4. Vacuum Processing: This involves not only simple vacuum chambers and furnaces, but also the mechanisms of vacuum chamber operation and liquid application equipment. Extensive knowledge of specialized vacuum equipment and components such as vacuum pumps, piping, and valves is required.
5. Precise Positioning: This requires the corresponding positioning technology and experience to achieve efficient calibration systems tailored to mechanical positioning and image processing needs. To maintain long-term accuracy, precise positioning, including installation design, is essential, requiring control of the camera or positioning stage.
6. Laser Welding: If possible, various lasers such as CO2, YAG, LED, and fiber lasers can be used based on individual needs. Examples include laser welding of lithium iron phosphate battery foil, welding of throttle valve housings and caps, and resin welding to replace metal. The most suitable welding method will be recommended based on specifications and the welding machine selected.
7. Pressing: Requires technical expertise and experience with various presses, such as air, hydraulic, and servo presses. We have extensive experience, from testing production levels with robotic arms pressing onto machine platforms to producing high-precision, high-quality products with controlled speed and torque using servo motors.
8. Dimensional Measurement: Dimensional measurements are performed using various methods, including laser displacement gauges, image processing equipment, and contact and non-contact sensors. In production machinery, accurate dimensions cannot be measured using measuring equipment alone. Therefore, comprehensive accuracy must be maintained, including considerations such as installation vibrations.
Before assembling lithium iron phosphate battery packs, it is necessary to calculate the required product size and load capacity of the lithium battery packs, then calculate the capacity of the lithium battery packs to be assembled based on the required capacity of the product, and then select lithium batteries based on the calculation results.
