Bipolar ear low internal resistance lithium ion secondary battery

Abstract

The invention relates to a bipolar ear low internal resistance lithium ion secondary battery comprising a shell, a positive electrode piece, a negative electrode piece, an isolation membrane arrangedbetween the positive and negative electrodes and an electrolyte filling in among the isolation membrane and the positive and negative electrode pieces. The bipolar ear low internal resistance lithiumion secondary battery is characterized in that the positive and negative electrode pieces and the isolation membrane form a winding core through a winding mode. The positive pole piece includes two pole ears, and the first pole ear of the two pole ears of the positive pole piece is located at the position of 5%-40% of the pole piece, the second pole ear is located at the position of 45%-90% of thepole piece. The negative pole piece includes two pole ears, and the two pole ears of the negative pole piece are located at the two ends of the pole piece. The internal resistance of the prepared battery cell can be reduced by 70% ~ 90% in comparison with the internal resistance of the single pole ear structure of the positive and negative electrodes; and the internal resistance can be reduced by40%-60% in comparison with the structure of the single pole ear of the positive electrode and the bipolar ears of the negative electrode, and the internal resistance can be reduced by 10%-30% in comparison with the structure that the bipolar ears of the positive and negative electrodes are arranged at the two ends.

Description

technical field [0001] The invention relates to a bipolar ear low internal resistance lithium ion secondary battery. Background technique [0002] Lithium-ion batteries have attracted more and more attention and use because of their advantages such as high voltage, high energy density, good cycle performance, and no memory effect. The application field has also developed from traditional digital products to power automotive products, Magnification electric tools products. High-rate power tool products have higher requirements for lithium-ion batteries because of their fast motor speed and high instantaneous current requirements. According to Joule's law Q=I 2 RT, when the current is constant, the calorific value of the battery cell is proportional to the internal resistance of the battery cell. For lithium-ion batteries, the electrolyte is easy to decompose and produce gas at a higher temperature, which will cause the battery to fail or cause safety hazards. Therefore, for...

AI Technical Summary

Problems solved by technology

[0003] At present, the mainstream cell structures on the market are basically positive and negative monopole lugs, or positive pole monopole lugs, negative pole bipolar lugs, or positive pole bipolar lugs but the tabs are at both ends, negative pole bipolar lugs, etc. These structures When doing some small currents, it has less influence on the battery core, but when the current is above 20A or even above 30A, the above-mentioned structures have high internal resistance, and the temperature of the battery core will be too high during long-term discharge.

Images