Points To Note In The Design Of High-rate Lithium Battery Packs
Sep 14, 2020
Single high-rate lithium batteries have excellent performance, but power batteries will only appear in the form of battery packs. In the course of use, it was found that the excellent performance of single lithium batteries after being assembled into battery packs will be greatly discounted. This is because the consistency, heat treatment, and vibration resistance of single high-rate lithium batteries are poor.
The structure design of the high-rate battery pack needs to meet the following six principles:
①The selected high-rate lithium battery cell should have stable discharge performance;
②Take certain temperature control measures to ensure that the battery pack works in a suitable temperature range;
③Ensure high-rate batteries Set a certain mechanical strength to meet the vibration requirements in a suitable environment;
④The high-rate battery pack meets the insulation requirements and flame-retardant requirements according to the use requirements of the power environment;
⑤The design should be easy to install and maintain;
⑥The battery packs should be easy to connect in series connection.
In the structural design of high-rate battery packs, battery operating temperature field control is an important research aspect. The performance of large-capacity, high-power power lithium batteries is particularly sensitive to temperature changes, mainly due to high-temperature problems caused by high-power , It will cause the decomposition of the electrolyte inside the battery, the decomposition of the SEI film, and the reaction between the electrolyte and the positive and negative electrodes. Optimize the battery pack structure to make the battery pack work in a suitable temperature field to avoid thermal runaway in the battery pack. The core problem to be addressed in the thermal management of lithium batteries is how to avoid thermal runaway of lithium batteries. This scheme is mainly designed from the battery pack structure to ensure that the battery pack works in a suitable temperature range and meets the road and ship transportation strength requirements of the battery pack.
High-rate battery pack module structure design
The battery module materials are made of high-strength plastic materials. The thickness of the bottom of the battery pack is strengthened, and multiple horizontal and vertical ties are arranged, and the battery installation slot is reserved inside the box. In order to reduce the vibration during the working and transportation of the battery pack, rubber pads are attached to the battery installation slot, and multiple sets of ribs are added to the side panel. Fan mounting holes are reserved on the front panel, and nuts are embedded on the side panel of the battery pack.
High-rate battery packs may vibrate during transportation and actual working conditions. The vibration of the battery module will loosen the connection between the battery pole and the copper bar, resulting in increased resistance and excessive temperature rise at the contact point. The excessively high current may fuse the loose copper bars, and the battery module is easily damaged when the vibration is large. Under different working conditions, vibration analysis is required to ensure the stability of the battery module under transportation and actual working conditions. Perform vertical axis random vibration, lateral axis random vibration, longitudinal axis random vibration, transportation random vibration, and actual ship vibration analysis on the battery module. After simulation analysis, the system meets the technical requirements of vibration.