Power lithium ion battery and production method thereof

Abstract

The invention relates to a power lithium ion battery and a production method thereof. The power lithium ion battery comprises a square casing, a battery cell sealed in the casing, an upper cover plate of the battery and a lower cover plate of the battery, wherein the upper cover plate is provided with a positive terminal and a negative terminal; the battery cell is formed by connecting small cylindrical battery cells in parallel; the small battery cells are formed by winding positive plates, diaphragms and negative plates and are provided with positive lugs and negative lugs; and the positive lugs and the negative lugs are positioned at the same ends of the small battery cells and connected by collecting plates at the lower parts of a T-shaped lug boss. The battery cell of the power lithium ion battery can effectively avoid the phenomenon that the battery is swollen and avoid the hot press reshaping work procedure before entering the casing, improve the safety performance of the battery and meet the requirement for heavy current discharge.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a power lithium ion battery. Background technique [0002] Lithium-ion battery is a kind of rechargeable battery, which is the representative of modern high-performance battery. Lithium-ion batteries are widely used in products such as notebook computers, video cameras, digital cameras, mobile phones, and power tools. [0003] Lithium-ion batteries in the prior art generally adopt a winding structure, and the shape is generally made into a cylinder or a square. Among them, the cylindrical battery generally includes a cylindrical shell and a cylindrical winding core placed in the shell. The advantages of the cylindrical battery are compact structure, good pressure resistance, high assembly ratio, not easy to bulge, and suitable for mass production; The battery generally includes a shell and a square winding core placed in the shell. The advantage of the square battery is tha...

AI Technical Summary

Problems solved by technology

[0005] (1) The disadvantages of cylindrical batteries are: the battery capacity is low, and the capacity of a single cell is generally less than 5Ah. When combined into a large-capacity, high-voltage battery pack, a large number of single cells is required, and the performance of the single cells is consistent when the battery is combined. It is difficult to guarantee the performance of the battery pack, resulting in the overall performance of the battery pack not meeting the design requirements; cylindrical batteries are sometimes limited by the size of the battery pack and cannot be used

[0006] (2) The disadvantage of the prismatic battery is that the winding core of the battery generally undergoes a hot-pressing shaping process before being put into the casing, so that the structure of the positive and negative electrodes of the winding core is compact. The hot-pressing shaping process causes the production cost of the square battery to increase, and also It is easy to cause the positive and negative electrode sheets to break at the bends, thereby affecting the electrical performance of the battery. What is more serious is that the electrode sheet breaks are likely to produce burrs to pierce the diaphragm, causing a short circuit of the battery, thereby affecting the safety performance of the battery; even if the battery is increased In the hot pressing and shaping process, the positive and negative electrode sheets of the winding core are still relatively loose, and the ion conductivity between the electrode sheets and the electronic conductivity between the active materials on the electrode sheets are low, resulting in a low utilization rate of the active materials in the battery. Poor current discharge capacity, large internal resistance of the battery, large thermal effect during charging and discharging, etc., and the battery is prone to bulging

Images