Electrode plate porosity measurement and calculation method

Abstract

The invention discloses an electrode plate porosity measurement and calculation method, which includes the following steps: materials are first chosen to prepare paste; paste density and paste solid content are measured; according to the paste density, paste solid content and the density of the chosen solvent, comprehensive true density is worked out; according to compaction density needed by an electrode plate, the paste is utilized to be applied on the surface of the electrode plate, and the surface of the electrode plate is compacted; and according to the compaction density and the comprehensive true density, the porosity of the electrode plate is worked out. The electrode plate porosity measurement and calculation method provided by the invention is efficient and effective, and can carry out data acquisition and calculation in the process of battery production without requiring a separate experiment; moreover, such a measurement and calculation method overcomes the problems of overhigh cost, menace engendered to the health of testers, difficulty in waste mercury treatment and great test errors existing in mercury intrusion porosimetry; and such a measurement and calculation method has guiding significance for both battery design and technological parameter optimization.

Description

technical field [0001] The invention belongs to the technical field of pole piece porosity testing, and in particular relates to a method for measuring and calculating the pole piece porosity. Background technique [0002] The porosity of the pole piece is an important parameter in the design and manufacture of lithium-ion batteries. It is closely related to the rate performance, internal resistance, cycle life and liquid injection volume of the battery design; the large porosity of the pole piece will lead to The integrity of the conductive network of the battery pole piece is poor, the internal resistance of the battery increases, and the uniformity of the current distribution on the pole piece deteriorates, resulting in a reduced cycle life. If the porosity of the pole piece is low, although the internal resistance of the battery will be reduced, it will As a result, the liquid absorption capacity of the battery is reduced, and the rate and cycle performance of the batter...

AI Technical Summary

Problems solved by technology

[0002] The porosity of the pole piece is an important parameter in the design and manufacture of lithium-ion batteries. It is closely related to the rate performance, internal resistance, cycle life and liquid injection volume of the battery design; the large porosity of the pole piece will lead to The integrity of the conductive network of the battery pole piece is poor, the internal resistance of the battery increases, and the uniformity of the current distribution on the pole piece deteriorates, resulting in a reduced cycle life. If the porosity of the pole piece is low, although the internal resistance of the battery will be reduced, it will As a result, the liquid absorption of the battery is reduced, and the rate and cycle performance of the battery are significantly reduced. Therefore, the porosity of the pole piece is very important to the performance of the battery.

[0003] The porosity of pole piece is generally tested by mercury porosimetry, which is not only expensive but also uses mercury medium for testing. Mercury metal is highly toxic and easily volatilizes into mercury vapor during the test process, which is a potential hazard to the health of the test personnel. The final waste mercury treatment is very troublesome; not only that, the mercury porosimeter has natural defects in testing the porosity of the battery pole piece, and there is a hemp effect between the metal mercury and the surface of the pole piece in the low-pressure stage (the wetting of the metal mercury and the surface of the pole piece is not enough in the low-pressure stage, There are gaps between the interfaces), resulting in part of the mercury injection in the low-pressure stage filling the interface gaps, and part of the injection into the large pores of the pole piece, and the two cannot be distinguished, resulting in a relatively large porosity of the pole piece tested by the mercury porosimeter

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