Method for detecting expansion force of lithium battery

Abstract

The invention relates to a method for detecting the expansion force of a lithium battery in the field of battery testing, and the method comprises the steps of data measurement, data processing, mathematical model construction, expansive force conversion and the like, a strain gauge is adopted to measure battery data, the expansive force is calculated by constructing a mathematical model of expansive force and a strain value. By adopting the strain gauges, the required deformation quantity and expansive force can be obtained under the condition that the structure of the battery is not influenced, high-precision measurement can be ensured, and long-term stable operation can be realized, so that the expansive force of the battery pack can be tested.

Description

technical field [0001] The invention relates to the field of battery testing, in particular to a method for detecting the expansion force of a lithium battery. Background technique [0002] Lithium-ion battery packs are first made of small cells connected in series and parallel to form a module, and then modules are connected in series and parallel to form a battery pack. In the process of charging and discharging the lithium battery pack, due to the expansion of the battery cells, there will be different degrees of pressure between the cells, between the modules and between the modules and the walls of the battery pack. Extrusion, but the extrusion force caused by the expansion needs to be quantified by engineers with the help of a test system. [0003] In the prior art, the rigid pressure sensor is generally sandwiched between the cells that generate the expansion force, between the modules and the modules, and then the expansion force is measured by designing the acquisi...

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Problems solved by technology

[0003] In the prior art, the rigid pressure sensor is generally sandwiched between the cells that generate the expansion force, between the modules and the modules, and then the expansion force is measured by designing the acquisition system at the back end. Most of these sensors are rigid. material, and the larger the measuring range, the larger the space occupied. Originally, the modules can be regarded as seamlessly fitted. After the sensor is installed, there will be a large gap between the modules, and the battery pack The original structure is destroyed, and the measured pressure has a large error, which cannot reflect the real situation during the charging and discharging process of the battery pack, or a flexible thin-film pressure sensor is sandwiched between the battery cells, or the module and the module Between the groups, the pressure value is read through the acquisition system, but due to the limitations of the resistance wire material, the measurement accuracy and sensitivity of this type of sensor are poor, and the allowable pressure range for measurement is small