38.4V 39Ah lithium battery design scheme for emergency X-ray

 Custom case     |      2021-12-03 11:39


Foreword: According to customer requirements, we designed an emergency power supply lithium battery based on the requirements of the power supply for the field emergency X-ray machine, the field ultrasound machine, the power failure emergency X-ray machine, and the field medical equipment. The battery pack uses IFR26650 lithium iron phosphate batteries and imported chips with high safety, high consistency, high stability and long life, and MOS tubes for protection and control management of the battery pack. The entire battery pack has the ability to continuously work with high current. The continuous output power can reach 1000W, and the instantaneous maximum power can reach 2KW. The battery pack can be equipped with UPS to provide emergency power supply for most medical equipment.



Design requirements

1. Lithium battery design requirements for emergency X-ray machines:

According to product specifications and customer requirements, the intelligent high-current lithium battery is designed to match the host, and features such as high-specification safety performance, good charge and discharge performance, high current working capability, and outstanding cycle life are integrated into the solution.



2. Design scheme of lithium battery for emergency X-ray machine:

1) Protection board (PCM): According to the chemical characteristics of the lithium iron phosphate battery and the working characteristics of the X-ray machine, the protection circuit is specifically designed. In addition to the overcharge, overdischarge, overcurrent, and short circuit protection functions, the protection board The design also fully considers the issues of high-power heat dissipation and the balance of the entire battery pack.

2) Protection circuit: Imported IC and MOS tubes are used to perform online real-time monitoring of overcharge, overdischarge, overcurrent, short circuit and other functions of the cell. Make the batteries work in a safe, stable and efficient range.

3) Overcurrent fuse: Mainly designed for secondary protection. 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 an output short circuit, which may cause danger Occurs, so an over-current fuse is added to the scheme. When an abnormal short circuit occurs, the fuse opens the circuit and cannot be restored to achieve the purpose of abnormal protection.

4) Battery: LARGE26650/3.2V/3000mAh lithium iron phosphate battery is used. The battery has a maximum charge rate of 1C and a maximum discharge rate of 2C. The battery itself has multiple safety protection functions. The battery has a built-in management system, which can effectively avoid battery safety issues.

5) The parameters of the whole set of batteries: 38.4V/39Ah (normally nominal 36V/39Ah), the normal working current is 35A, the maximum working current can reach 60A, and the instantaneous starting current can reach 100A.

6) Battery pack: Resistive balance is adopted between the cells of the battery pack, which can compensate for the reduction in capacity caused by the difference of single cells during use, and maximize the service life of the battery.

7) The battery pack uses a plastic bracket to isolate and fix the cells, which is more conducive to the heat dissipation and safe use of the battery.