CN110767935A - A kind of lithium ion elliptical structure battery and preparation method thereof - Google Patents

Abstract

The present invention discloses a lithium-ion elliptical structure battery and a preparation method thereof, wherein the battery comprises a battery cell, a packaging film coated on the outside of the battery cell, and a positive electrode ear and a negative electrode ear arranged on the side wall of the battery cell, wherein the positive electrode ear and the negative electrode ear are parallel to each other and face the same direction, and the cross section of the battery cell is elliptical, and the positive electrode ear and the negative electrode ear are located at the short axis position of the ellipse. The present invention can effectively reduce the space occupied by the package and facilitate storage and packaging by setting the battery cell to be elliptical, setting the positive electrode ear and the negative electrode ear in the same direction, and setting the positive electrode ear and the negative electrode ear in the short axis position of the ellipse, thereby effectively solving the technical problems existing in the prior art that the diameter of the folding position of the pole ear of the soft-pack cylindrical battery is large, the actual utilization space is small, and there is a large restriction on improving the battery energy density.

Description

A kind of lithium ion elliptical structure battery and preparation method thereof

technical field

The invention relates to the technical field of lithium ions, in particular to a lithium ion elliptical structure battery and a preparation method thereof.

Background technique

Lithium-ion batteries have the characteristics of high energy density, fast charge and discharge, recyclability and long life, and have become the mainstream of the battery energy market, and are widely used in military and civilian products. With the development of society, people's requirements for lithium-ion batteries are not only limited to the reliability and safety of batteries, but also have higher and higher requirements for battery performance and structure.

With the rise of wearable products, the miniaturization and diversification of battery products are becoming more and more obvious. At the same time, due to the increasing requirements for the battery life of equipment, manufacturers are required to improve product performance as much as possible on the premise of ensuring product performance. The internal space of the battery product is actually used to improve the energy density, and at the same time, the structure design of the battery should be carried out in accordance with the internal structure of the end product.

At present, there are two structures for small cylindrical batteries: one is the steel shell structure, which uses a steel shell to encapsulate the positive, negative, separator, and electrolyte in it, and the steel shell is usually a metal material, such as Stainless steel or aluminum alloy, etc., not only make the material cost high and heavy, but also have dangerous safety hazards such as explosion; the other is a soft-pack structure, which has the advantages of light weight and good safety performance. At present, the soft-pack cylindrical battery has two types of structures with both positive and negative poles, and two types of poles. The energy density of the battery is limited, especially for the miniaturized cylindrical battery. However, the structure of the same end of the tab, the size utilization rate of the tab folded position is not high, which affects the energy density per unit diameter.

SUMMARY OF THE INVENTION

Aiming at the problems in the related art, the present invention proposes a lithium-ion elliptical structure battery to overcome the technical problems of the prior art, such as large space occupied by the tabs and small space for practical use.

The technical solution of the present invention is achieved as follows: a lithium-ion elliptical structure battery includes a battery cell, a packaging film wrapped on the outer side of the battery core, and a positive electrode lug and a negative electrode lug disposed on the side wall of the battery core, the said The positive electrode tab and the negative electrode tab are parallel to each other and have the same orientation, the cross section of the battery cell is oval, and the positive electrode tab and the negative electrode tab are located at the position of the short axis of the ellipse.

Preferably, the positive electrode tab and the negative electrode tab are located on the short-axis circumference of the same ellipse.

Preferably, the positive electrode tab and the negative electrode tab are parallel to the axis of the cell; the positive electrode tab and the negative electrode tab are located at the same height on the side wall of the cell.

Preferably, the battery cell includes a positive electrode sheet, a separator, and a negative electrode sheet that are stacked and wound in sequence; the positive electrode tab is connected to the positive electrode sheet, the negative electrode tab is connected to the negative electrode sheet, and the positive electrode tab is connected to the negative electrode sheet. and the negative electrode pass through the encapsulation film and extend out of the encapsulation film.

Preferably, the packaging film is an aluminum-plastic film, and the aluminum-plastic film is oval.

Preferably, the outer wall of the encapsulation film is provided with tab sealing edges for encapsulating the positive electrode tabs and the negative electrode tabs; preferably, the tab sealing edges are elliptical.

The present invention also provides a preparation method of the above-mentioned lithium ion elliptical structure battery, wherein the preparation method steps include:

Step S1, connecting the positive electrode tab and the negative electrode tab at one end of the positive electrode sheet and the negative electrode sheet respectively;

Step S2, stacking the positive electrode sheet, the separator and the negative electrode sheet in turn and winding them into a battery cell, wherein the positive electrode tab and the negative electrode tab are respectively arranged at the end of the wound positive electrode sheet and the negative electrode sheet;

Step S3, processing the battery cell into an oval shape, and making the positive electrode lug and the negative electrode lug at the position of the short axis of the ellipse;

Step S4, placing the battery cell in the packaging film for packaging, and performing liquid injection, chemical formation, molding, volume separation, and cutting and edge sealing in sequence;

Step S5 , after cutting and sealing, the positive electrode tab and the negative electrode tab are shaped and processed so that the positive electrode tab and the negative electrode tab are parallel to the axis of the cell, and the lithium ion elliptical structure battery can be obtained.

Preferably, in the step S4, before placing the battery cell in the packaging film for encapsulation, the positive electrode tab and the negative electrode tab are respectively bent into a horizontal state, wherein the bending of the positive electrode tab and the negative electrode tab are in the same way as the electrical The edges of the core are flush; in the process of placing the battery cell in the packaging film for packaging, a heat sealer is used to heat seal the penetrating joints between the positive electrode tab and the negative electrode tab and the packaging film.

In the present invention, by setting the battery cell into an oval shape, the positive and negative electrodes are arranged in the same orientation, which can effectively reduce the space occupied by the package and facilitate the storage and packaging, and the positive and negative pins are arranged on the short axis of the ellipse. , which can effectively solve the technical problems in the prior art, such as the large diameter of the folded edge position of the tabs of the soft-pack cylindrical battery, the small actual utilization space, and the large restriction on improving the energy density of the battery.

Description of drawings

FIG. 1 is a schematic side view of a battery with an elliptical structure according to an embodiment of the present invention.

FIG. 2 is a schematic side structure diagram of the elliptical structure battery according to the embodiment of the present invention from another viewing angle.

FIG. 3 is a schematic structural diagram of one of the battery cells according to the embodiment of the present invention.

FIG. 4 is another schematic structural diagram of the battery cell according to the embodiment of the present invention.

FIG. 5 is a schematic flow chart of the preparation method of the embodiment of the present invention.

The reference numbers in the figure are: 10-cell, 11-positive tab, 12-negative tab, 20-encapsulation film, 30-short axis position, 40-pole tab edge sealing.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art fall within the protection scope of the present invention.

Example 1

Referring to FIGS. 1 to 4 , the lithium ion elliptical structure battery provided in this embodiment includes a battery cell 10 , a packaging film 20 covering the outer side of the battery cell, and a positive electrode tab 11 and a negative electrode disposed on the side wall of the battery cell. Ears 12, the positive and negative electrodes are parallel to each other and face the same direction, the cross section of the cell is oval, and the positive and negative electrodes are located at the position 30 of the short axis of the ellipse. Preferably, the outer wall of the encapsulation film is provided with a tab edge 40 for encapsulating the positive electrode tab 11 and the negative electrode tab 12 ; correspondingly, the tab edge 40 is preferably elliptical.

In one of the preferred embodiments, the packaging film is preferably an aluminum-plastic film, and the aluminum-plastic film is oval. In this embodiment, the battery cell includes a positive electrode sheet, a separator, and a negative electrode sheet that are stacked and wound in sequence; the positive electrode tab is connected to the positive electrode sheet, the negative electrode tab is connected to the negative electrode sheet, and the The positive tab and the negative electrode pass through the encapsulation film and extend out of the encapsulation film. Preferably, the positive electrode tabs are connected to the positive electrode tabs by welding, and the negative electrode tabs are connected to the negative electrode tabs by welding.

As a preferred embodiment, the positive electrode lug and the negative electrode lug are located on the short-axis circumference of the same ellipse; the positive electrode lug and the negative electrode lug are parallel to the axis of the battery cell; the positive electrode lug and the negative electrode lug are The heights on the side walls of the cells are the same. With this arrangement, the space occupied by the positive electrode tab and the negative electrode tab can be made smaller, the space utilization rate can be effectively improved, and the energy density of the battery can be increased.

3 is a schematic diagram of the structure of the battery cell, in this FIG. 3, the packaging film has not been wrapped on the battery core 10, the battery core 10 is stacked and wound by the positive electrode sheet, the separator, and the negative electrode sheet in turn The positive electrode lug 11 and the negative electrode lug 12 are arranged at the end of the winding positive electrode sheet and the negative electrode sheet, and the positive electrode lug and the negative electrode lug are parallel to each other and have the same orientation, and the positive electrode lug and the negative electrode lug are located on the short axis of the ellipse. bit 30. Wherein, the separator is arranged between the positive electrode sheet and the insulating sheet to play an insulating role. After winding into a battery cell, the positive electrode lug 11 and the negative electrode lug 12 are first bent into a horizontal shape, as shown in FIG. If required, then bend the positive electrode and the negative electrode by 90° in opposite directions, and the positive electrode 11 and the negative electrode 12 can be in a horizontal state. Afterwards, heat-sealing the junctions of the positive electrode tabs and the negative electrode tabs with the packaging film by a heat sealer, and finally set the tab seals for encapsulating the positive electrode tabs 11 and the negative electrode tabs 12 on the outer wall of the packaging film. The structure shown in Figure 2 can be obtained. Among them, the sealing edge of heat sealing is 360° surrounding the packaging film. In addition, in Fig. 3 and Fig. 4, since the positive electrode sheet, the separator and the negative electrode sheet are thin and inconvenient to label, the specific positions of the positive electrode sheet, the separator and the negative electrode sheet are not specifically marked. When winding the battery core, from the inside to the outside, it is the positive electrode sheet, the separator, and the negative electrode sheet.

Compared with the prior art, the ion elliptical structure battery provided by the embodiment of the present invention can effectively reduce the space occupied by the package and facilitate storage by setting the battery cell into an elliptical shape and setting the positive and negative electrodes in the same direction. packaging, and by arranging the positive and negative electrodes at the short-axis position of the ellipse, it can effectively solve the problem that the diameter of the folded edge of the soft-pack cylindrical battery in the prior art is large, and the actual utilization space is relatively small. There are technical problems such as large restrictions on improving the energy density of batteries.

Embodiment 2

In this embodiment, a preparation method of the lithium ion elliptical structure battery described in the above embodiment is provided. As shown in FIG. 5 , the steps of the preparation method include:

Step S1, connecting the positive electrode tab and the negative electrode tab at one end of the positive electrode tab and the negative electrode tab respectively; in this embodiment, between the positive electrode tab and the positive electrode tab, and between the negative electrode tab and the negative electrode tab are connected by welding;

Step S2, stacking the positive electrode sheet, the separator and the negative electrode sheet in turn and winding them into a battery cell, wherein the positive electrode tab and the negative electrode tab are respectively arranged at the end of the wound positive electrode sheet and the negative electrode sheet;

Step S3, processing the battery cell into an oval shape, and making the positive electrode lug and the negative electrode lug at the position of the short axis of the ellipse, as shown in FIG. 3;

Step S4, placing the battery cell in the packaging film for packaging, and sequentially performing processes such as liquid injection, chemical formation, molding, volume separation, and cutting and edge sealing;

Step S5, after cutting and sealing, the positive electrode tab and the negative electrode tab are shaped and processed, so that the positive electrode tab and the negative electrode tab are parallel to the axis of the cell, and the lithium ion elliptical structure battery can be obtained, as shown in Figure 1 shown. The edge sealing here refers to the edge sealing of the tabs in Example 1.

As a preferred embodiment, in the step S4, before placing the battery cell in the packaging film for packaging, the positive electrode tab and the negative electrode tab are respectively bent into a horizontal state, wherein the positive electrode tab and the negative electrode tab are bent It is flush with the edge of the cell, as shown in Figure 4; wherein, in this embodiment, the positive electrode and the negative electrode are bent into a horizontal state by bending the positive electrode and the negative electrode by 180° in opposite directions. Then, according to the position requirements of the positive and negative electrodes, the positive and negative electrodes are bent 90° in opposite directions to form a horizontal state. In this embodiment, during the packaging process of placing the battery cell in the packaging film, a heat sealing machine is used to heat seal the junctions between the positive electrode tab and the negative electrode tab and the packaging film, wherein the sealing edge of the heat sealing is 360° surrounding the encapsulation film.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. The battery with the elliptic lithium ion structure is characterized by comprising an electric core (10), a packaging film (20) coated on the outer side of the electric core, and a positive electrode lug (11) and a negative electrode lug (12) which are arranged on the side wall of the electric core, wherein the positive electrode lug and the negative electrode lug are parallel to each other and have the same orientation, the cross section of the electric core is elliptic, and the positive electrode lug and the negative electrode lug are positioned at the position of an elliptic short shaft position (30).

2. The battery of claim 1, wherein the positive electrode tab and the negative electrode tab are located on the circumference of the short axis of the same ellipse.

3. The battery with the elliptical lithium ion structure of claim 2, wherein the positive electrode tab and the negative electrode tab are parallel to the axis of the cell.

4. The battery of claim 4, wherein the positive tab and the negative tab are at the same height on the side wall of the cell.

5. The battery with the elliptical lithium ion structure of claim 1, wherein the battery core is formed by sequentially stacking and winding a positive plate, a diaphragm and a negative plate; the positive tab is connected with the positive plate, the negative tab is connected with the negative plate, and the positive tab and the negative electrode penetrate through the packaging film and extend out of the packaging film.

6. The battery of claim 1, wherein the packaging film is an aluminum-plastic film, and the aluminum-plastic film is elliptical.

7. The battery with an elliptical lithium ion structure according to claim 1, wherein the outer wall of the packaging film is provided with a tab seal (40) for packaging the positive tab and the negative tab.

8. A preparation method of a lithium ion battery with an oval structure comprises the following steps:

step S1, connecting a positive tab and a negative tab to one end of the positive tab and the negative tab respectively;

step S2, sequentially overlapping and winding the positive plate, the diaphragm and the negative plate into a battery cell, wherein the positive tab and the negative tab are respectively arranged at the ending ends of the wound positive plate and negative plate;

step S3, processing the battery cell into an elliptical shape, and enabling the positive electrode tab and the negative electrode tab to be at the positions of short axes of the ellipse;

step S4, placing the battery cell in a packaging film for packaging, and sequentially performing liquid injection, formation, molding, capacity grading and edge sealing by cutting;

and S5, cutting and edge sealing, and shaping the positive tab and the negative tab to make the positive tab and the negative tab parallel to the axis direction of the battery cell, thereby obtaining the battery with the elliptical lithium ion structure.

9. The method of claim 8, wherein in step S4, before the cell is placed in the encapsulation film for encapsulation, the positive tab and the negative tab are bent to a horizontal state, wherein the bent portions of the positive tab and the negative tab are flush with the edge of the cell.

10. The method of claim 8, wherein: in step S4, in the process of placing the battery cell in the packaging film for packaging, the crossing point of the positive tab and the negative tab and the packaging film is heat sealed by a heat sealing machine.

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