Do I need high-power chargers for large-capacity lithium iron phosphate batteries?

Technical Secret: One of the important trends for large-capacity lithium iron phosphate batteries to require a high-power charger for patient care is the increasing use of remote monitoring systems in patients’ homes. The reason for this trend is obvious: the cost of hospitalizing patients is unaffordable. Therefore, many portable electronic monitoring systems include radio frequency transceivers so that data can be sent directly to the hospital monitoring system for discussion and analysis by doctors. Obviously, this type of system is usually powered by alternating current, batteries, or both. This redundancy is necessary to ensure that the system can continue to operate outside the hospital. In addition, some new developments have been made in the field of portable medical diagnostic equipment, such as equipment carried by doctors and nurses, which use batteries as an important power source or backup power source when AC power is interrupted. This system requires an efficient battery charging circuit. In addition to medical applications, portable industrial bank terminals, rugged tablet computers, inventory control and barcode scanners all require a large-capacity battery to reduce the size and weight of the device. Lithium batteries are the most popular choice. However, charging the battery quickly, accurately, and safely is a trivial task. In addition, new lithium-based chemical positive/negative combinations have been developed, and these combinations are also entering the mainstream market. An example of this trend is that lithium iron phosphate (LiFePO4) batteries have appeared in many applications, which have higher safety and longer battery life than cobalt-based lithium ion/lithium polymer batteries. In addition, this chemical battery also has many other advantages of cobalt lithium batteries, including low self-discharge rate and relatively lighter components. In contrast, in addition to improved safety (due to its ability to withstand thermal runaway) and longer battery life, lithium iron phosphate batteries also have a higher peak power rating and have a smaller impact on the environment. General medical and industrial applications are willing to accept lower energy density per unit volume in exchange for greater safety and longer cycle life. The backup requires a longer cycle life and high current discharge capability. How to get more energy The power architecture of many handheld industrial or medical devices is usually similar to a smart phone with a large screen. In general, because the energy density per unit volume (Wh/kg) and energy density per unit volume (Wh/m3) of lithium batteries are both high, 3.7v (final charging voltage or floating voltage is 4.2v) lithium is usually used The battery is used as a primary power source. In the past, many high-power devices used two 7.4v (8.4v floating voltage) lithium batteries to meet power requirements, but since IC introduced low-cost 5V power supplies, more and more handheld devices have chosen a low-voltage architecture , Allows the use of a lithium battery. A typical portable medical or industrial device has many functions and a very large (in the case of a portable device) display screen. When using a 3.7v battery for power supply, its capacity should be calculated in kilowatt hours. In order to charge such a large battery in a few hours, a charging current of several amperes is required. However, even with such a large charging current, when no high-current AC adapter is available, users still want to use the USB port to charge their high-energy devices. In order to meet this requirement, the battery charger must be able to operate at high current (2A) when the AC adapter is available, but still effectively utilize the power from the USB port 2.5w to 4.5w. In addition, integrated circuit products must maintain sensitive downstream low-voltage components to protect them from over-voltage work that may be caused by damage, and effectively guide the large current from USB input, ac adapter or battery to the load to minimize Power loss in the form of chemical heat. Integrated circuits are necessary to safely process battery charging algorithms and monitor key system parameters. The low 3.6v start-up and floating voltage of the lithium iron phosphate battery makes it impossible to use a standard lithium battery charger. If the charging is improper, it may cause irreparable damage to the battery. Accurate floating charging will extend battery life. Compared with cobalt-based lithium batteries, the advantages of LiFePO4 batteries include higher capacity energy density (unit capacity) and lower risk of premature failure (if the new battery is deeply cycled prematurely). Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Is the decay of ternary lithium batteries really irreversible?