24V IFR32700 18Ah Lifepo4 Battery Portable UPS Batteries

At present, there are more and more articles promoting the fast charging of power batteries, some manufacturers' publicity, some excessive, and some experts also follow the trend and say that 30 minutes, 15 minutes can complete the charging of electric vehicles, and more ridiculous, saying that the charging task can be completed within 5 minutes. The author expressed concern that these propaganda will be detrimental to the development of the industry, and people engaged in engineering understand that "the principle does not work, and the engineering cannot be passed", and the principle of lithium-ion batteries has told people that they cannot be charged quickly.

1. What is fast and slow charging?

On-board batteries have positive and negative poles, and those that can charge the battery must be a DC power supply with positive and negative poles. What do you mean? The alternating current from the grid cannot directly charge the on-board battery.

However, to charge electric vehicles, they are all 220V for civilian use, or 380V alternating current for factories. Why is that? This is a "alternating current-to-direct current (AC/DC)" device used by engineers to turn alternating current into direct current. For the average user, keep in mind that:

(1) The power supply for charging the on-board battery must be DC power supply, and the AC power supply cannot "directly" charge the lithium-ion battery.

(2) Where is the DC power supply? At present, the electricity in the power grid is alternating current. The direct current used to charge an electric vehicle is converted through an "alternating current-to-direct current (AC/DC)" device.

(3) "ALTERNATING CURRENT-DC (AC/DC)" is a device that meets the requirements of the standard. If this device is installed in the car, the car and the charging interface are the AC charging interface; If this device is installed under the car (ground), the car and the charging interface are AC and DC interfaces.

(4) The alternating current (AC/DC) device can be made into a high-power device on the ground (note: the greater the power, the larger the volume and the heavier the mass; However, automobiles have insulation requirements, volume and weight restrictions, so the AC/DC in the vehicle is low power.

The first level is the concept of "fast and slow". The charging speed of the DC interface is faster than that of the AC charging interface. In principle, the charging speed of the DC interface is 3 hours to 4 hours, and the AC charging interface is 6 hours to 8 hours. (Note: The power grid can guarantee the provision of 220V for civil use, or 380V AC for factory use)

The second level is the concept of "fast and slow". At present, the charging speed of the theoretical DC interface is 3 to 4 hours, compared with 5 minutes of refueling for fuel vehicles. Due to the limitations of the principle, some experts put forward the concept of "30 minutes (or 15) charging to 80%", there is still 20% space, and the charging time is ignored. In other words, the whole process of charging is segmented.

The third level is the concept of "fast and slow". The DC interface cannot be fast, which means that the whole process is from 3% to 99%, and it is fully charged; The DC port can be charged quickly, basically referring to 20% to 80% of the entire space. This is part of the lithium-ion battery charge (discharge) curve. Some manufacturers have made some optimizations to this curve. In principle, there is no substantial innovation.