3.7V Lithium Polymer Battery

　　What is the reason for the short service life of 3.7V Lithium Polymer Battery (you need to know these three points)

　　The development of 3.7V Lithium Polymer Battery has been very mature today. Compared with the past structural design and materials, there has been great progress. The performance of the battery has also been greatly improved, so that its theoretical life can reach 15 to 20 years. More than 10 years, but anyone who has actually used it knows that there are very few or even no 3.7V Lithium Polymer Battery that can last this long. Why do you say this?

　　We can take low-maintenance 3.7V Lithium Polymer Battery as an example, which are more common in cars and motorcycles. The batteries on these vehicles are dry-charged 3.7V Lithium Polymer Battery, which are used for starting vehicles. The service life of these batteries is designed to be 4 ~5 years, but in actual use, it only takes a year or even a few months from the beginning of use to the replacement of the battery. This is true for low-maintenance batteries. The service life of batteries that require frequent maintenance can be imagined, so why does this happen? The phenomenon can be roughly divided into the following three points:

　　1. The battery charging equipment is imperfectly designed and inconvenient to use;

　　2. The lead-acid battery is not fully charged in time after use, and excessive discharge has a great impact on the battery;

　　3. Some manufacturers sell low-quality products and use some miscellaneous brands to pass themselves off as good brands.

　　The second and third points of these reasons are actually easier to judge and solve, but the first reason is difficult to solve, because this is what the manufacturer needs to do, and we can analyze it.

　　In fact, the design service life of a lead-acid battery is the result of the battery being used at an ambient temperature of 25°C. The voltage of a single lead-acid battery will drop by about 4mv for every 1°C increase in ambient temperature. So a 12V battery composed of six single batteries connected in series The float charge voltage of the battery pack is 13.5V at 25°C; if the ambient temperature drops to 0°C, the float charge voltage becomes 14.1V; when the ambient temperature rises to 40°C, the float charge voltage becomes 13.14V.

　　3.7V Lithium Polymer Battery also have a characteristic. When the ambient temperature is constant, the charging voltage is 100mv higher than the required voltage, and the charging current will increase several times, which will lead to thermal runaway and overcharge damage of the battery; if the charging voltage is higher than the required voltage, If the voltage is 100mv lower, insufficient charging of the battery will cause battery damage.

　　Temperature not only affects the charging of 3.7V Lithium Polymer Battery, but also affects the capacity of the battery. Every time the ambient temperature drops by 1°C, the capacity will also decrease by 1%. Therefore, when using the battery in summer, companies discharge 50% of the rated capacity before charging, and in winter, discharge 25% of the rated capacity. % also needs to be charged. In daily use, there is no guarantee that the ambient temperature is always 25°C. The ambient temperature changes all the time, and the temperature difference between spring, summer, autumn and winter is even greater. Therefore, there are various lead-acid battery chargers on the market, with constant voltage or The battery is charged using a constant current method, but it still cannot meet the technical requirements for battery charging.

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