Seven DIY steps for lithium iron phosphate batteries

1. Choose the appropriate battery cell, and match the type, voltage, and internal resistance of the battery cell. Before assembly, please balance the battery cells, cut the electrodes, and drill holes.

2. Calculate the distance based on the hole and cut the insulation board.

3. Install screws. Please use flange nuts to prevent them from falling off. After the screws are connected, the battery pack can be secured.

4. When connecting welding wires and voltage acquisition wires (balance wires), do not connect external protective boards to avoid accidental burning of the protective boards.

5. Secure the insulating silicone again. This type of silicone will cure for a long time.

6. Place protective boards. If you forgot to balance the battery unit before, this is your last chance before assembling the battery. You can balance it through the balance line.

7. Fix the entire lithium battery pack with an insulation board and wrap it with nylon tape. Nylon tape is more durable. Please be careful not to use steel shells. Although the steel shell is beautiful and sturdy, it is difficult to ensure the integration of the battery cells. If some shells are not handled properly, they may scratch the battery cells and cause leakage, and even cause accidents due to poor insulation.

8. When packaging the battery as a whole, please make sure to fix the battery and protective plate securely. When the battery cell falls from a height of 1 meter, it must function properly.

9. The final packaging is completed, and both the output and input are made of silicone wire.

Installation precautions for LFP battery pack
The open circuit voltage must be measured before installing the LFP battery pack. The open circuit voltage difference cannot exceed 50mV. Battery testing should be conducted and documented.

Although the positive and negative plates of the LFP battery pack are already activated through charging and discharging when it leaves the factory. If the installation date and delivery date of the LFP battery pack are far apart, the LFP battery pack will inevitably lose its capacity after long-term self discharge. In addition, LFP battery packs are generally charged at around 60% when leaving the factory. Therefore, lithium battery packs should be supplemented at the beginning of installation. In addition, due to the differences in self discharge of individual batteries, the terminal voltage of each individual battery may be unbalanced.

Before installing a new LFP battery pack, it is necessary to measure the open circuit voltage and keep a record of the battery test. Capacity testing can be conducted on the battery pack at false loads at hourly rates of 0.1C10 (A) and 0.2C5 (A). There is no need to connect to the battery management system for this test, just connect the battery pack in series, but during the discharge process, the voltage of the battery cells must be strictly tested.

During the testing process, the total voltage, discharge current, and individual voltage of the battery should be measured every hour and recorded. Only when the battery terminal voltage reaches 2.5V, immediately stop discharging and calculate whether the actual battery discharge capacity is basically consistent with the rated capacity of the battery.

If the discharge capacity of the battery pack differs significantly from the rated capacity (greater than 15%) when the discharge reaches the termination voltage, it indicates that there may be a problem with the factory capacity of the lithium battery pack. Relevant manufacturers should be contacted in a timely manner for handling.

Maintenance of LFP battery pack
(1) Working environment requirements for LFP battery packs

Requirements for working environment of LFP battery pack: According to the environmental requirements of the battery, the room temperature should not exceed 55 ℃, and it is recommended to maintain the ambient temperature between 0 ℃ and 55 ℃. Avoid direct sunlight on the battery, and windows facing the sun should be shaded. Ensure that there is sufficient maintenance space between the lithium battery packs.

(2) Precautions for using LFP batteries

It is prohibited to use LFP battery packs of different specifications and models in the same DC power supply system, and batteries of different old and new levels shall not be mixed in the same DC power supply system.

If there is a centralized monitoring system for power and environment, the total voltage, current, single module voltage, temperature, and capacity of the battery pack should be monitored in real-time through a dynamic environmental monitoring system and BMS. At the same time, the battery monitoring device is used to understand the charging and discharging curves and performance of the battery, and regular testing is conducted to promptly address faults.

(3) Frequent inspection items for LFP batteries

Regularly check if the poles and connecting bars of the LFP battery are loose. Is there any damage, deformation, or corrosion. Whether the connection is loose, whether the battery case is damaged, leaking or deformed, and whether the battery temperature rise and connection are abnormal.

Based on the technical parameters provided by the manufacturer and on-site environmental conditions, check whether the voltage of the battery pack and individual module meets the requirements, and check whether the charging current of the battery pack during intermittent float charging is within the required range. Check if the charging current limit value of the battery pack is set correctly. Check if the low voltage alarm and high voltage alarm settings of the battery pack are correct.

(4) Voltage requirements for voltage equalization and float charging operation of LFP batteries

The intermittent charging voltage of an LFP battery pack is generally set to 3.60-3.76V for individual batteries, with a high-voltage DC output voltage of 278V. Measure the voltage of the battery pack and the terminal voltage of the individual battery every month, and compare it with the battery monitoring display to solve problems in a timely manner.

What aspects do you need to pay attention to when maintaining a lithium battery pack?
1. Charge according to standard time and program, with the first XNUMX consecutive presses;

2. Lithium battery packs should be stored in a cool, dry, and safe environment;

3. The activation of lithium battery packs does not require any special methods, and lithium batteries will naturally be activated during normal phone use. If you insist on using the popular "first three 12 hour long charging activation" method, it is actually not feasible.

4. Avoid placing lithium batteries near heat sources, open flames, flammable and explosive gases, liquids, which may cause battery leakage, heating, smoking, fire, and explosion.

5. If lithium batteries need to be stored for a long time (more than a month), it is recommended to charge them to 40% -60%. During use, the battery needs to be charged for 1-2 hours per month. Storage time.

The above are the precautions for installation and maintenance of LFP battery packs. In addition to manufacturers having to recognize and prevent the safety risks that may arise from using lithium batteries, ordinary consumers also have a responsibility to face the hazards of lithium batteries and understand how to be safe. Use to reduce accidental injuries caused by lithium battery packs.

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