A method for improving electrochemical and shock-proofing performance of power-driven lithium ion battery

Abstract

The invention relates to a lithium ion cell, especially an electrocar power-type lithium ion. And its characteristic: firstly designing and making a box, then placing cell polar pieces in the box, using a cell cover to connect the box and fixing them and then placing in a cell case; then welding the cell cover with the cell case into an integral whole, so as to compose the good-performance power-type lithium ion cell. In producing course, thy yield of product is increased from 66% of traditional technique to 100%; the cell capacity is increased and the internal resistance is obviously reduced, the charge-discharge property of the cell is obviously improved, and the maximum pulse discharge current multiplication can reach 15 CA; the cell capacity and internal resistance distribution are relatively consistent and centralized, remarkably enhancing the property of the cell groups applied in electromobiles or electric tools.

Description

Technical field: [0001] The invention relates to a lithium ion battery, in particular to a power type lithium ion battery for electric vehicles. Background technique: [0002] The traditional assembly method of power lithium-ion batteries is to firstly assemble the positive electrode, negative electrode and diaphragm by stacking, that is, the sheet-shaped positive electrode, negative electrode and diaphragm are assembled by using the "negative electrode, diaphragm, positive electrode, and diaphragm". The units are overlapped, and a negative electrode is superimposed on the last unit. Each pole piece is connected with the current output terminal (pole) through a current collector; then the stacked battery core is wrapped with a diaphragm or tape and put into a metal or plastic casing. This assembly method has the following disadvantages: [0003] (1) Due to the looseness between the positive and negative plates of the battery, problems such as low utilization of battery act...

AI Technical Summary

Problems solved by technology

[0003] (1) Due to the looseness between the positive and negative plates of the battery, problems such as low utilization of battery active materials, poor high-current discharge capacity, large internal resistance of the battery, and large thermal effect during charging and discharging are caused;

[0004] (2) Since the thickness of the current collector of the pole piece connected to the pole is <0.02mm / pcs, it cannot bear the longitudinal pressure, and the longitudinal tension it can bear is also quite limited

The relative movement between the positive and negative pole pieces of the battery is easy to occur, and the tabs are easy to pull or break, which leads to short-circuit and micro-short-circuit phenomenon of the battery during production and use, resulting in low yield and reliability of battery production;

[0005] (3) When electric vehicles are running, especially when driving on uneven roads, the vehicle body vibrates greatly. Under vibration, relative movement between the battery pole pieces, between the battery core and the casing is easy to occur, and the performance is unstable.

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