Common Failure Forms of Panasonic Batteries

1. Imbalance



Most lead-acid batteries are not used separately, but many are used together, such as: "Electric vehicle batteries usually start with three or four batteries in one repair process." One or two of each batteries lag behind, which can lead to other good batteries can not be used normally, which is called imbalance.



2. Water loss



In the process of battery charging, the electrolysis of water will occur, resulting in oxygen and hydrogen, so that water is lost in the form of hydrogen and oxygen, so it is also called gas evolution. Water plays a very important role in the electrochemical system of batteries. Reducing the amount of water will reduce the ionic activity involved in the reaction, reduce the contact area between sulphuric acid and lead plate, increase the internal resistance of batteries, increase polarization, and ultimately lead to the decrease of the capacity of batteries.



3. Sulfation



Lead sulfate is produced in both positive and negative electrodes during battery discharge. Lead sulfate is easily converted to lead dioxide during charging due to the existence of oxygen oxidation on the positive electrodes, while the negative electrodes are different. In the case of long-term power-deficit preservation, frequent over-discharge and long-term undercharging, a layer of uniformity will gradually form on the surface of the negative electrodes. The dense and hard lead sulfate layer not only greatly reduces its solubility and is difficult to participate in the reaction, but also blockages the contact channels between electrolyte and deep active substances, which leads to the decrease of battery capacity.



4. Polar plate softening



The plate is a multi-void material with a much larger specific surface area than the plate itself. During the repeated charging and discharging cycles of the battery, with the alternation of different materials on the plate, the void rate of the plate will gradually decrease. In appearance, the surface of the positive plate will gradually change from solid to soft at the beginning. When it becomes pasty, the decrease of surface area will lead to the decrease of battery capacity. High current charge-discharge and over-discharge will accelerate the softening of the plate.



5. grid corrosion



At present, there are three kinds of alloys used in production, traditional lead-antimony alloys, low or ultra-low antimony alloys and lead-calcium series. The grids made of these three alloys will be oxidized to lead sulfate and lead dioxide during the charging process of batteries, which will lead to the failure of batteries due to the loss of supporting active substances. Later, the shape of lead dioxide corrosion layer will lead to the failure of batteries. The skeleton grid of battery is made of lead alloy. Although it has strong corrosion resistance, long-term immersion in acidic electrolyte will cause metal corrosion, even grid cracks. Fracture, resulting in capacity decline.



6. Short circuit



The positive and negative plates should be separated by the diaphragm (plate), but if there is welding slag or dendrite penetration, the positive and negative plates want to connect and form a short circuit. Serious short circuit can cause the monomer voltage to become zero. If the resistance of the positive and negative connected material itself is larger, such as dendrite, it will not immediately make the single cell voltage to zero, but rather. Faster self-discharge occurs, commonly known as soft short circuit.



7. Open the way



Usually occurs in the stage of confluence welding, pole welding and terminal welding. The manifestation is virtual welding instead of complete circuit breaking. At this time, there will be a great internal resistance at the virtual welding site, which will lead to the decline of Panasonic battery capacity. It is possible that all aspects of the battery are normal at the beginning, and virtual welding occurs after a period of time. This is usually due to the lack of welding and cracks in the welding process. During the use process, the area will produce tip corrosion, resulting in cracks to increase at a faster rate.



Repair method: 100A test battery voltage 0V for open circuit, using a single measurement method, measure the open circuit place, weld well.



Battery repair can restore some performance of the battery to a level close to that of the new battery by various means.



Commonly used battery repair methods [2]?



1. Imbalance



Repair method: Find out the capacity, voltage, self-discharge, battery resistance and other batteries have been used together.



2. Water loss



Repair method: pry open the cover plate above the battery. The caps of some batteries are bonded with ABS glue, and some batteries are buttoned. Some are skateboards. Be careful not to damage the cover when you pry it open. At this time, you can see six rubber caps of exhaust valves. Open the rubber cap and expose the exhaust hole, through which you can see the inside of Panasonic battery. The base of exhaust valve of some batteries can be switched off, so the base of exhaust valve can be switched on without opening the rubber exhaust valve. Some batteries have some fillers around their rubber caps. Open the lid and light it with a flashlight to see if there is drying up inside the orifice, that is, whether the battery is dehydrated. The plate of the battery is wrapped in white fiberglass cotton, which should be wet under normal conditions. Distilled water is inhaled by dropper and injected into battery through exhaust hole. Cover the vent with a breathable shield to prevent dust from falling into the vent. Good use of medical secondary distilled water. The principle of replenishing water is that less is better than more. Not enough to add, more acid caused by the decline in the proportion of battery capacity will be insufficient. The inexperienced can master it at 5mL per hole. Good to see Jia, wet, shiny, watery. It's just wet. It's more shiny and watery.



Special tips: glass, plastic and other pipettes are used in water supply tools. It is suggested to use disposable syringe for medical use, which is convenient to use and convenient to measure. Water supply tools should not use any metal-containing equipment. The syringe should be used after pulling out the metal needle and putting a plastic tube.



3. Sulfation



Repair method: The vulcanized batteries were repaired by pulse repair instrument, and the high voltage (30V-50V) pulse (8330HZ) low current (battery nominal capacity) was used.