Design requirements: 1. Design requirements of lithium battery for electric forklift: The battery is designed for supporting the use of logistics forklifts. It requires small size and a relatively long working time. It can drive two motors: one is to drive the vehicle and the other is to drive the lifting object. Our lithium iron phosphate battery electric forklift is designed with a total power of 800W, and instant power of 1000W, moisture-proof appearance, long cycle life, high-power, high-current discharge performance; the whole product adapts to the indoor environment, and the temperature rise is low. 2. Design scheme of lithium battery for electric forklift: 1) Protection Board (PCM): According to the chemical characteristics of the lithium iron phosphate battery and the working characteristics of the forklift, the protection circuit is specifically designed. In addition to the functions of overcharge, over-discharge, overcurrent, and short circuit protection, the protection board design also fully considers the issues of high-power heat dissipation and the balance of the entire battery pack. The entire protection board uses aluminum alloy as the heat dissipation substrate, and the temperature rise is less than 20 degrees. 2) Protection circuit: Imported IC and MOS tubes are used to perform online real-time monitoring of overcharge, over-discharge, overcurrent, short circuit, and other functions of the cell so that the cell can work in a safe, stable, and efficient range. 3) Overcurrent fuse: Mainly designed for the protection failure of the battery management system of the lithium battery itself. Because the battery pack uses high-power cells with a relatively large capacity, although the battery management system has over-current and short-circuit protection if an abnormality occurs, the protection function will fail, and a very large current will be generated in the case of output short-circuit, causing danger Occurs, so an over-current fuse is added to the program. When an abnormal short circuit occurs, the fuse opens the circuit and cannot be restored, achieving the purpose of abnormal protection. 4) Battery: LARGE26650/3.2V/3000mAh lithium iron phosphate battery is used. The maximum charging rate of the battery can reach 1C and the maximum discharge rate can reach 2C. The battery itself has multiple safety protection functions. The cell has a built-in thermistor (PTC), and the unit structure also uses PTC isolation when combined to prevent the occurrence of surge current. 5) The parameters of the whole battery pack: 25.6V/80Ah (usually nominal: 24V80Ah). The normal working current is 30A, the maximum working current is up to 50A, and the instant starting current is up to 120A. 6) Resistive balancing is used inside the battery pack, which can effectively compensate for the capacity reduction caused by the difference of single cells during use, and maximize the service life of the battery. 7) Battery parallel unit: PTC isolation is used to avoid inrush current safety problems caused by large capacity. 8) The high-current main circuit of the battery uses copper tape as the collector bar, and try to keep the discharge current of the single battery as close as possible. 9) The battery pack uses a plastic bracket to isolate and fix the cells, which is more conducive to heat dissipation and safe use of the battery.
