Repair principle and method of 18650 lithium battery

Lithium battery fix two principles: low temperature enables the lithium battery electrolyte in change, just freeze-promoting chemical reaction of the battery. The use of lithium batteries is actually a charging and discharging process. During this period, the negative and positive charges in the battery collide with each other. The reason why the battery is becoming more and more useless is because under normal room temperature, the internal kinetic energy of the electron is relatively large, so the battery is in an active state and the leakage is relatively frequent. When the lithium battery is placed in a low temperature environment, the lithium film on the surface of the lithium battery and the microstructure of the electrolyte, and their interfaces will change significantly, resulting in a temporary inactivity of the battery and a decrease in leakage current. Therefore, after recharging, the waiting time of the mobile phone will increase.

The lithium battery has a cycle life of about 600 times. If the number of times of charging is increased, the thermal motion of the molecule will gradually destroy the internal molecular arrangement microstructure, and the storage charge efficiency will gradually decrease. The "freezing process is easy to damage the original internal structure of the battery, and may increase the capacity to charge the charge in a short period of time, but long-term use may not be effective." Once the microstructure of the lithium battery is destroyed, it is impossible to completely recover it. Long-term use of this method will accelerate the loss of the mobile phone battery.

The principle of lithium battery repair method three: deep discharge of the mobile phone is to exhaust the internal power to achieve a deeper degree of recharging, which requires some unconventional methods. Try to connect the phone to a 1.5V small light bulb, and the internal power of the lithium battery will be transferred to the small light bulb until it is all light. “The mobile phone needs to slowly run out of power through a lower voltage. Under normal circumstances, if the mobile phone is connected below the rated voltage of 3.6 volts, it will automatically shut down.” After the battery is discharged, the rechargeable battery can be used again.

18650 lithium battery repair method:

1. Take all your batteries out and take them down. Use temperature treatment. The battery will greatly shorten the use time when the temperature is unstable. Because the battery is not charged, and a considerable part of the lithium ions have been used for memory. This method can make a part of the memory power release, winter is over, put it outside for a while, then go to the house.

2, there is a way to remove the battery, put it for about a week, the electricity will be slowly consumed, you need to use the machine to completely consume the electricity. Then fully rush, it is estimated that your current charging time must be very short, after the full, disconnected and rushed, repeated several times, absolutely effective.

Battery repair is a general term for repairing a secondary battery that has degraded or failed performance by physical or chemical means. By repairing, the battery capacity can be restored, the battery life can be extended, and the performance of the battery can be improved.

A battery, also known as a chemical power source, is a device that can provide a DC power source for an electrical appliance. The chemical power source converts chemical energy into electrical energy through an electrochemical reaction of redox. The primary battery is a one-time application battery, and the secondary battery is a battery that can be used repeatedly, so the second time here actually means multiple times. Secondary batteries are also known as rechargeable batteries or batteries.

Battery repair refers to the collective repair of batteries that have degraded or failed performance by physical or chemical means.

A secondary battery, also referred to as a "rechargeable battery", refers to a battery that can be activated by activation of the active material after the battery is discharged. The main rechargeable batteries on the market are "nickel hydride", "nickel cadmium", "lead acid (lead battery)", "lithium ion (including lithium battery and lithium ion polymer battery )" and the like. There are many methods for repairing lead-acid batteries, such as "water therapy", "shallow cycle high-current charging method", "nano-carbon sol battery activator repair", "pulse battery repair instrument repair", "battery repair fluid repair" and so on.

Sulfation

Irreversible sulphation, referred to as sulphation. When the lead-acid battery is discharged, the positive and negative plates produce a combination of lead sulfate. Lead sulfate is a poorly soluble, non-conductive substance under normal conditions. The leaching of lead sulfate formed by the battery after discharge is relatively small. When charging, it is relatively easy to dissolve and reduce to lead under the action of electricity. If used improperly, it is often insufficiently charged, dehydrated, over-discharged, etc. When coarse and hard crystals are formed, it is difficult to reduce them to lead by a general method, so it is called irreversible sulfation. On the one hand, it can block the contact of sulfuric acid with other active substances due to sulfation. Reacts: On the other hand, the amount of active material is reduced, which can cause the battery capacity to drop, and in severe cases, the battery life will be terminated.

Exfoliation of actives

When we repair used batteries, some batteries are filled with water and some reddish brown liquid flows out from the water injection hole. It is the active substance that falls off. The reasons for the falling off of the active substance are as follows: 1. The battery is affected by external force, such as vibration, beats and so on. 2, α-PbO2.βPbO2 variant model: αPbO2 is the active material skeleton, when the battery is charged and discharged, a part of α-PbO2 is converted into β-PbO2, resulting in softening and shedding. 3, with the cycle, activity The material is gradually crystallized from the amorphous state, that is, the crystallinity increases, the number of hydrated polymer chains decreases, the gel pressure resistance increases, the electrical contact between the grains deteriorates, and the active material falls off. 4. It is also believed that with charging And the discharge continues, the active material forms a number of dense agglomerates. When there is insufficient connection between the agglomerates, the active material will fall off and the battery will fail.

Battery voltage

The potential difference between the positive and negative poles of the battery is called the voltage of the battery. It is generally measured with a multi-meter. During the battery repair process, the voltage has three manifestations: the first type is the no-load voltage, also known as the open circuit voltage, that is, the battery is not charged. Battery voltage measured without load: The second type is the load voltage, which is the battery voltage measured during a certain period of battery discharge. The third type is the line voltage, which is measured at a certain time during the charging process. The voltage, understand three voltage measurement methods, to determine whether the battery is open or short circuit; battery internal resistance calculation has important significance.

Battery capacity

The capacity of the battery is an important indicator to measure the performance of the battery. It is generally expressed in ampere-hour. The general term for discharge time (hours) and discharge current (amperes), ie capacity = discharge time × discharge current. The actual capacity of the battery depends on The amount of active material in the battery and the utilization rate of the active substance. The more the active substance is, the higher the utilization rate of the active material, and the larger the capacity of the battery. The smaller the capacity is.

Hydrotherapy

For the vulcanized battery, the battery can be discharged first, and the original electrolyte is poured out and the electrolyte is diluted to a density of 1.10 g/cm3 or less, that is, the electrolyte is diluted with water to increase the solubility of lead sulfate. Use a current below 20h, charge in a range where the liquid temperature does not exceed 20 °C ~ 40 °C for a long time, and finally adjust the density of the electrolyte in the battery to the concentration of the standard solution with a slightly higher electrolyte under sufficient power, generally vulcanization Can be released, the capacity is restored to more than 80% can be considered successful.

The mechanism of this method is to reduce the acid solution density to increase the solubility product of sulfate, and to take a small current for a long time to reduce the ohmic polarization and delay the early emergence of the water decomposition voltage, and finally the vulcanization phenomenon is gradually reduced in the dissolution and conversion into active substances. Or eliminate.

The characteristics of this method are more suitable for water-filled batteries, and can be repeatedly treated for serious vulcanization phenomenon. It can be repaired without investment equipment. The disadvantage is that the process is too cumbersome and is not practical for sealed batteries.

Shallow cycle charging

For the vulcanized battery, the current is used within a high current rate of 5h. It is better to charge the battery to a slightly overcharged state to control the liquid temperature not to exceed 40 degrees, and then discharge 30%. This repeated several times can reduce and eliminate the vulcanization phenomenon.

The mechanism of this method uses a super-charged gas to wash the surface of the plate with a slight sulfide, so that it is desorbed and dissolved and converted into an active substance.

The characteristics of this method can be obviously repaired for slight vulcanization. However, it is not suitable for the old battery because the precipitated gas washes out the sulfate and also strongly violently ignites the active material of the positive electrode plate, so that the active material becomes soft or even falls off.

Repair instrument repair

For vulcanized batteries, the battery can be charged and discharged several times with a dedicated pulse repairer to eliminate vulcanization. [1]

The mechanism of this method, from the solid physical point of view, any insulating layer can break down at a sufficiently high voltage. Once the insulating layer is broken down, it will change from an insulated state to a conductive state. If an instantaneous high voltage is applied to the sulfate layer having a large conductivity difference value, large lead sulfate crystals can be broken. If the high voltage is short enough and the current is limited, in the case of breaking through the vulcanized layer, controlling the charging current is appropriate, and the battery is not decomposed. The amount of gas outflow depends on the terminal voltage of the battery and the magnitude of the charging current. If the pulse width is short enough and the duty cycle is large enough, under the condition of ensuring the breakdown of the coarse sulphate crystal, the simultaneous micro-charging can not form the gassing. If the negative pulse is depolarized, the gas of the plate is more likely to be precipitated when the sulfate layer is broken, thus achieving pulse elimination vulcanization. The characteristics of this method, the pulse repair charger on the market is uneven, many pulse chargers and even the special repair instrument pulse width ratio, duty cycle, negative pulse design is not reasonable to go to the role of desulfurization.

Nano carbon sol battery activator repair

Battery activator: Nano-carbon sol is a type of nano-carbon material. Nano-carbon material means that at least one of the dispersed phase scales

A carbon material with a dimension is less than 100 nm. Under the action of electric field, the active component of the activator can solidify the plate; disintegrate irreversible sulfate crystal; uniformly adsorb on the surface of the plate to form a protective film to prevent the active material from falling off and the plate vulcanization, polarization, lead The formation of crystallization; activation of the active material of the battery; reducing the internal resistance of the battery, and improving the electrochemical reaction of the battery. This kind of repairing liquid only has a better repair effect on the battery, and the repaired battery can be used for more than 12 months.