CN202495539U - Lithium ion battery - Google Patents

Abstract

The utility model belongs to the technical field of lithium-ion batteries, and in particular relates to a lithium-ion battery with a good packaging effect, which includes an electric core and a packaging bag for containing the electric core. The air bag of the packaging bag is provided with a heat-proof radiation pit. Compared with the prior art, the utility model sets a heat-resistant radiation pit at the air bag. Although the aluminum foil material near the head of the battery core has heat transfer when it is vacuum-packed, at the position of the heat-resistant radiation pit, the upper and lower layers of aluminum foil of the air bag Without direct contact, it will not cause the polypropylene layer between the two aluminum foils to fuse, which is conducive to the complete extraction of the gas generated after the formation in the degassing process, ensuring the quality of the battery pack and various electrical properties. At the same time, the anti-heat radiation pit can also increase the gas storage space of the cell air bag to a certain extent, and even shorten the length of the cell air bag, save packaging aluminum foil materials, and reduce production costs.

Description

A lithium ion battery

technical field

The utility model belongs to the technical field of lithium ion batteries, in particular to a lithium ion battery with good packaging effect.

Background technique

With the continuous development of modern society, lithium-ion batteries are more and more widely used in notebook computers, MP3, MP4, digital cameras, mobile phones, mobile DVD and even the automobile industry due to their advantages such as high energy density, small self-discharge and no environmental pollution. and other fields.

The use of lithium-ion batteries is a process of continuous charging and discharging. There are organic solvents and electrolyte lithium salts that can quickly decompose and produce a large amount of hydrofluoric acid in the presence of water and oxygen. Once the hydrogen fluoride (HF) content in the battery is too high, The electrical performance of the battery (such as capacity, cycle life, discharge platform, etc.) will be lost, which seriously affects the use of the battery. Therefore, the packaging reliability of the battery plays a key role in the normal use of the battery. Only by keeping the inside of the battery in a vacuum, oxygen-free, and water-free environment can the performance of the lithium-ion battery meet the requirements of use.

As shown in Figure 1, generally speaking, a soft-packed lithium-ion battery includes a battery cell 3 and a packaging bag 4 for packaging the battery cell 3. The packaging bag 4 generally adopts an aluminum-plastic composite film, which has a three-layer structure: polypropylene A (PP) layer, a nylon layer, and an aluminum layer spaced between the polypropylene layer and the nylon layer. When packaging the battery cell 3 , in order to discharge the gas generated inside the battery cell 3 after formation, an air bag 5 is generally designed. At present, there is no special design for the air bag 5 of the packaging bag 4 in the flexible packaging lithium-ion battery. The air bag 5 has a flat planar structure. When the vacuum sealing side 6 is heat-sealed, the heat conduction of the metal aluminum layer of the packaging aluminum foil will cause thermal fusion of the polypropylene layer in some areas of the air bag 5 and affect the subsequent vacuum packaging quality.

The impact of this packaging bag is particularly significant for some small batteries with small volume and short air bag length (≤20mm). Specifically, after the battery cell 3 is packaged by the vacuum packaging side 6, due to heat radiation, the upper and lower packaging aluminum foil areas of the air bag 5 of the packaging bag 4 will be fused, and in the deflation process, the bayonet piercing position has It may just fall on these fusion zones, so that the excess gas generated by the formation of the battery cell 3 cannot be completely pumped out and remains inside the battery cell 3, affecting the performance of the battery cell 3, and even causing the battery cell 3 to be scrapped directly.

In view of this, it is indeed necessary to provide a lithium-ion battery with good encapsulation effect.

Utility model content

The purpose of the utility model is to provide a lithium-ion battery with good encapsulation effect in view of the deficiencies of the prior art.

In order to achieve the above object, the utility model adopts the following technical solutions:

A lithium-ion battery includes a battery cell and a packaging bag for containing the battery cell. The front end of the battery cell is provided with a positive electrode tab and a negative electrode tab, and the air bag of the packaging bag is provided with a heat radiation-proof pit.

Compared with the prior art, the utility model sets the anti-heat radiation pit at the air bag. Although the aluminum foil material near the head of the battery core has heat transfer when it is vacuum-packed, the upper and lower layers of aluminum foil of the air bag are placed at the position of the anti-heat radiation pit. Without direct contact, it will not cause the polypropylene layer between the two aluminum foils to fuse, which is conducive to the complete extraction of the gas generated after the formation in the degassing process, ensuring the quality of the battery pack and various electrical properties. At the same time, the anti-heat radiation pit can also increase the gas storage space of the cell air bag to a certain extent, and even shorten the length of the cell air bag, save packaging aluminum foil materials, and reduce production costs.

As an improvement of the lithium-ion battery of the utility model, the heat-resistant radiation pit is arranged in the central area of the air bag to facilitate side sealing and top sealing.

As an improvement of the lithium-ion battery of the utility model, the heat radiation prevention pit is in the shape of a cuboid.

As an improvement of the lithium-ion battery of the utility model, the length direction of the heat radiation prevention pit is parallel to the protruding direction of the positive electrode tab or the negative electrode tab.

As an improvement of the lithium-ion battery of the utility model, the width direction of the heat radiation prevention pit is perpendicular to the protruding direction of the positive electrode tab or the negative electrode tab.

As an improvement of the lithium-ion battery of the utility model, the central area of the air bag is provided with two heat-proof radiation pits facing each other, and an empty groove is formed between the two heat-proof radiation pits. In this way, the distance between the packaging aluminum foil at the anti-heat radiation pit can be further ensured that the polypropylene layer at the anti-heat radiation pit will not be fused, and the air storage space can be increased at the same time.

Description of drawings

The utility model and its beneficial technical effects will be described in detail below in conjunction with the accompanying drawings and specific embodiments, wherein:

Fig. 1 is the structural schematic diagram of the lithium-ion battery of prior art;

Fig. 2 is a structural schematic diagram of the lithium-ion battery of the present invention.

Detailed ways

The utility model is described in detail below in conjunction with accompanying drawing:

As shown in Figure 2, the lithium-ion battery of the utility model includes a battery cell 1 and a packaging bag 2 for accommodating the battery cell 1. The front end of the battery cell 1 is provided with a positive pole tab 11 and a negative pole tab 12. The packaging bag 2 The air bag 21 is provided with heat radiation pit 22.

Wherein, the packaging bag 2 generally adopts an aluminum-plastic composite film, which has a three-layer structure: a polypropylene (PP) layer, a nylon layer, and an aluminum layer spaced between the polypropylene layer and the nylon layer.

For the lithium-ion battery of the present utility model, when the vacuum sealing side 23 carries out the heat sealing operation, the upper and lower two-layer packaging bags 2 at the position of the anti-heat radiation pit 22 will not directly contact, thereby preventing the polypropylene layer on the packaging bag 2 from occurring. Heat fusion, and at the same time, the aluminum foil packaged in the left air bag area of the heat-proof radiation pit 22 will not reach the melting temperature of polypropylene due to the long distance of radiation heat transfer, so heat fusion will not occur. The above two points are enough to ensure the pumping process. The position of the bayonet edge does not fall on the fusion zone of the aluminum foil during gas, so as to ensure that the cell can complete the pumping and packaging operation with high quality.

Wherein, the heat-proof radiation pit 22 is arranged in the central area of the air bag 21, the heat-proof radiation pit 22 is in the shape of a cuboid, and the length direction of the heat-proof radiation pit 22 is parallel to the positive pole lug 11 or the negative pole. The protruding direction of the ear 12 , the width direction of the heat radiation prevention pit 22 is perpendicular to the protruding direction of the positive electrode tab 11 or the negative electrode tab 12 .

The heat radiation prevention pit 22 can be punched out using a mechanical die. The width of the anti-heat radiation pit 22 should be 3-5 mm, and the depth of the punching pit should not be too deep, and should be controlled at 2-3 mm, so as to prevent the packaging aluminum foil from being damaged due to excessive deformation during molding.

The distance between the right edge of the anti-heat radiation pit 22 and the right edge of the air bag 21 is enough to ensure that the vacuum packaging edge 23 can complete the space required for the packaging operation. It is better to keep the distance of more than 6mm to ensure that the outgassing sealing edge can be packaged smoothly, and at the same time there is enough sealing width space; The space required to seal the header.

The central area of the airbag 21 can also be provided with two heat radiation-proof pits 22 opposite to each other, and an empty space is formed between the two heat-radiation pits 22 . This can make the distance of the packaging aluminum foil at the heat-proof radiation pit 22 farther, further ensure that the polypropylene layer at the heat-proof radiation pit 22 will not fuse, and increase the gas storage space simultaneously.

According to the disclosure and teaching of the above specification, those skilled in the art to which the present utility model belongs can also make appropriate changes and modifications to the above embodiment. Therefore, the utility model is not limited to the specific implementation manners disclosed and described above, and some modifications and changes to the utility model should also fall within the scope of protection of the claims of the utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present utility model.

Claims (6)

1. A lithium-ion battery, comprising an electric core and a packaging bag to accommodate the electric core, the front end of the electric core is provided with positive pole tabs and negative pole tabs, it is characterized in that: the air bag of the packaging bag is provided with a heat-proof radiation pit. 2. The lithium ion battery according to claim 1, characterized in that: the heat radiation prevention pit is arranged in the central area of the air bag. 3. The lithium ion battery according to claim 1, characterized in that: the heat radiation prevention pit is in the shape of a cuboid. 4 . The lithium ion battery according to claim 3 , wherein the longitudinal direction of the heat radiation prevention pit is parallel to the protruding direction of the positive electrode tab or the negative electrode tab. 5 . The lithium ion battery according to claim 3 , wherein the width direction of the heat radiation prevention pit is perpendicular to the protruding direction of the positive electrode tab or the negative electrode tab. 6 . 6 . The lithium-ion battery according to claim 2 , wherein the central area of the air bag is provided with two heat-proof radiation pits facing each other, and an empty groove is formed between the two heat-proof radiation pits.

Images