CN202495508U - A kind of soft package lithium-ion battery and its tab - Google Patents

Abstract

The utility model belongs to the technical field of lithium-ion batteries, and in particular, relates to a soft-package lithium-ion battery pole ear, including a pole piece connecting section connected to a pole piece, a conducting section connected to the outside, and a transition section connecting the pole piece connecting section and the conducting section, the thickness of the transition section is less than the thickness of the pole piece connecting section and the thickness of the conducting section, and the upper and lower surfaces of the transition section are both bonded with a polymer material film layer. Compared with the prior art, the utility model adopts a structure in which the pole ear is partially thinned at the sealing position between the traditional pole ear and the aluminum-plastic packaging film. In this way, the gap between the upper and lower layers of the aluminum-plastic packaging film can be greatly reduced, ensuring the battery sealing and preventing electrolyte leakage or water vapor from entering. At the same time, this structure that is thinned only at the sealing position will not affect the mechanical strength and resistance value of the pole ear. In addition, the utility model also discloses a lithium-ion battery including the pole ear.

Description

A kind of soft package lithium-ion battery and its tab

technical field

The utility model belongs to the technical field of lithium-ion batteries, in particular to a soft-packed lithium-ion battery tab and a lithium-ion battery including the tab.

Background technique

With the advancement of technology, the application of mobile devices is becoming more and more extensive. The rapid growth of mobile devices has created a large demand for high energy density batteries. At present, lithium-ion batteries on the market can be divided into hard-packed batteries with stainless steel or aluminum shells and soft-packed batteries with aluminum-plastic composite films in terms of their outer packaging. Among them, flexible packaging batteries have achieved rapid development due to their higher energy density and better safety.

Flexible packaging batteries generally include a battery cell and an aluminum-plastic film packaging case. There are tabs at the front of the battery cell. The tabs pass through the packaging film and are connected to the outside world to provide energy when in use. At present, in order to make the tabs have a certain mechanical strength and relatively small impedance, metal tabs with a certain thickness are generally used, and the thickness of the entire tab is uniform, which makes it difficult to seal the tabs in the flexible packaging battery where the tabs pass through the packaging film. bigger. If the seal is not good, the battery is prone to liquid leakage or water vapor seeps into the battery, which will affect the quality of the product and may even cause safety problems.

In view of this, it is indeed necessary to provide a tab that can improve the packaging performance of a soft-packed lithium-ion battery to ensure battery quality and battery safety, as well as a lithium-ion battery containing the tab.

Utility model content

One of the purposes of the utility model is to provide a tab that can improve the packaging performance of a soft-packed lithium-ion battery to ensure battery quality and battery safety.

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

A soft-pack lithium ion battery tab, comprising a pole piece connecting section connected to the pole piece, a conduction section conducting with the outside world, and a transition section connecting the pole piece connection section and the conduction section, the transition section The thickness is smaller than the thickness of the connecting section of the pole piece and the thickness of the conduction section, and the surface of the transition section is bonded with a polymer material film layer. When packaging, the aluminum-plastic composite film of the battery outer package is sealed together by heat sealing, and the sealing area of the aluminum-plastic composite film at the tab is located on the polymer material film layer of the transition section.

As an improvement of the tab of the flexible package lithium-ion battery of the utility model, the thickness of the transition section is 10% to 99% of the thickness of the connection section or the conduction section of the pole piece. If the thickness of the transition section is less than 10% of the thickness of the pole piece connection section or the conduction section, it may cause stress concentration and strength change in the transition area between the transition section and the pole piece connection section or the conduction section. bad question.

As an improvement of the tabs of the soft-packaged lithium-ion battery of the utility model, the connecting section, the transition section and the conduction section of the pole piece are integrated.

As an improvement of the tab of the flexible package lithium-ion battery of the present invention, the transition mode between the transition section and the connection section of the pole piece is a vertical transition, an oblique transition or an elliptical transition.

As an improvement of the tab of the flexible package lithium-ion battery of the present invention, the transition mode between the transition section and the conduction section is a vertical transition, an oblique transition or an elliptical transition.

As an improvement of the tab of the soft-packaged lithium-ion battery of the utility model, a thinning area is provided on one side of the transition section.

As an improvement of the tabs of the soft-packaged lithium-ion battery of the present invention, both sides of the transition section are provided with thinning areas.

As an improvement of the tab of the flexible packaging lithium-ion battery of the utility model, the surface of the transition section is completely covered with a polymer material film layer.

As an improvement of the tab of the flexible packaging lithium-ion battery of the utility model, the surface of the transition section is partially covered with a film layer of a polymer material.

Compared with the prior art, the utility model adopts a partially thinned tab structure at the sealing position between the traditional tab and the aluminum-plastic packaging film. This can greatly reduce the gap between the upper and lower layers of aluminum-plastic packaging film, ensure the battery is sealed, and prevent electrolyte leakage or water vapor from entering. At the same time, the thinned structure only at the sealing position will not affect the mechanical strength and resistance value of the tab. In addition, the utility model does not need to introduce new materials, the manufacturing method is simple, and it is convenient for mass production.

Another object of the present utility model is to provide a lithium-ion battery, including a battery cell and an aluminum-plastic packaging film. The front end of the battery cell is provided with a tab, and the tab passes through the aluminum-plastic packaging film. The tab is the above paragraph When the tab is packaged, the sealing area of the aluminum-plastic packaging film at the tab is located on the polymer film layer of the transition section. Compared with the prior art, the lithium ion battery of the utility model has good packaging performance and safety performance.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described:

Fig. 1 is the utility model lithium-ion battery structural representation;

Fig. 2 is provided with the current collector of thinning groove for the utility model;

Fig. 3 is a schematic diagram of a tab with a thinning area on one side of the utility model;

Fig. 4 is a schematic diagram of tabs with thinning areas on both sides of the utility model;

Fig. 5 is a schematic diagram of a tab structure of the present invention;

Fig. 6 is a schematic diagram of another tab structure of the present invention;

Fig. 7 is the tab group of the utility model pasted with a polymer film material layer;

Fig. 8 is the tab of the utility model pasted with a polymer film material layer.

Detailed ways

As shown in Figure 1, a lithium-ion battery of the present invention includes a battery cell 7 and an aluminum-plastic packaging film 8, the front end of the battery cell 7 is provided with a tab 9, and the tab 9 passes through the aluminum-plastic packaging film 8, wherein , as shown in Figures 2, 3, 4 and 5, the tab 9 includes a pole piece connecting section 3 connected to the pole piece, a conduction section 1 conducting with the outside world, and connecting the pole piece connecting section 3 and conducting The transition section 2 of section 1, the thickness of the transition section 2 is smaller than the thickness of the pole piece connection section 3 and the thickness of the conduction section 1, and the surface of the transition section 2 is bonded with a polymer material film layer 6, so The pole piece connection section 3, the transition section 2 and the conduction section 1 are integrated, and the thickness of the transition section 2 is 10% to 99% of the thickness of the pole piece connection section 3 or the conduction section 1. When packaging, The sealing area of the aluminum-plastic packaging film 8 at the tab 9 is located on the polymer material film layer 6 of the transition section 2 .

Wherein, the transition mode between the transition section 2 and the pole piece connecting section 3 is a vertical transition, an oblique transition or an elliptical transition, and the transition mode between the transition section 2 and the conducting section 1 is a vertical transition, an oblique transition or Elliptical transition, wherein the transition section 2 can be provided with a thinned area on one side, or can be provided with a thinned area on both sides.

The surface of the transition section 2 may be completely covered with the polymer material film layer 6 , or may be partially covered with the polymer material film layer 6 .

Wherein, the manufacturing method of the flexible package lithium-ion battery tab 9 of the utility model is:

First, as shown in Figure 2, the thinning groove (transition section 2) that meets the corresponding size requirements is manufactured on the original metal sheet of the tab 9 by turning or milling. Two ways of thinning (as shown in Figures 3 and 4), the transition between the transition section 2 and the pole piece connecting section 3 can be a vertical transition, an oblique transition or an elliptical transition, and the transition section 2 and the conduction The transition mode between segments 1 can be a vertical transition, an oblique transition or an elliptical transition (as shown in Figures 5 and 6). Cutting the polymer material film layer 6 into strip-shaped materials;

Secondly, the thin metal plate is cut into metal strips along the direction perpendicular to the groove (transition section 2 ) according to the width requirement of the tab 9 . The metal strip is placed at intervals along the direction perpendicular to the polymer tape-shaped film material, so that the polymer film material layer 6 is located at the thinned groove (transition section 2) of the metal strip. Next, place the polymer film material layer 6 vertically on the above metal strip, and make the upper and lower polymer film material layers 6 overlap each other (as shown in FIG. 7 ). Heat the above-mentioned superimposed materials through a hot press, so that the metal strip and the polymer film material layer 6 are heat-combined together;

Finally, as shown in FIG. 8 , the two layers of polymer film material layers 6 and their composite metal strips are cut into tabs of the battery according to the corresponding size.

Specific implementation mode 1

First, the corresponding thinning groove (transition section 2) is manufactured on the metal (Ni, Al, Cu) thin plate of the current collector by turning or turning and milling. In this example, the single-side thinning method is used (as shown 3), the width of the groove (transition section 2) is 5mm, and the distance between two adjacent rows of grooves (transition section 2) is 45mm. The transition between the groove (transition section 2) and the conduction section 1 and the pole piece connection section 3 adopts vertical and inclined transition methods respectively (as shown in Figure 5);

Next, the metal sheet is slit into metal strips with a groove (transition section 2 ) having a width of 4 mm along a direction perpendicular to the groove (transition section 2 ). Then, respectively place one deck of polymer film material layer 6 up and down along the groove (transition section 2) of the above-mentioned metal band vertical direction, and make upper and lower two layers of polymer film material layer 6 overlap each other; then , hot pressing the above-mentioned stacked materials together, so that the metal current collector and the polymer film material layer 6 are combined together, as shown in Figure 7;

Finally, as shown in Figure 8, the polymer film material layer 6 and its composite current collector are cut into tabs 8 of the battery according to the required size, and the resulting tab conduction section 1 has a length of 10 mm and a thickness of 0.08 mm; The length of the sheet connection section 3 is 30mm, and the thickness is 0.08mm; the length of the transition section 2 is 5mm, and the thickness is 0.05mm; the width of the polymer film material layer 6 after thermal lamination is 4.5mm.

The tab 9 made above was used in a battery with a model number of 423482 (4.2mm in thickness, 34mm in width, and 82mm in length), and its impedance was tested. The impedance test result was 30.67mΩ (1KHz). After high-temperature and high-humidity experiments Afterwards, the failure rate of the tab 9 in the water soak test was 0.3ppm;

As a comparison group (the thickness of the three sections of the tab is 0.08mm), the impedance of the cell is 30.00mΩ (1KHz). After the same high-temperature and high-humidity test, the failure rate of the tab 9 at the soaking test is 0.7 ppm.

Specific implementation mode 2

First, the corresponding thinning grooves (transition section 2) are manufactured on the metal (Ni, Al, Cu) thin plate of the current collector by turning or turning and milling. In this example, double-sided thinning (as shown in Figure 4) is used. As shown), the width of the groove (transition section 2) is 5mm, and the distance between two adjacent rows of grooves (transition section 2) is 45mm. The transitions between the groove (transition section 2 ) and the conduction section 1 and the pole piece connecting section 3 respectively adopt oblique and elliptical transition modes (as shown in FIG. 6 ). Next, the metal sheet is slit into metal strips with a groove (transition section 2 ) having a width of 4 mm along a direction perpendicular to the groove (transition section 2 ). Then, respectively place one deck of polymer film material layer 6 up and down along the groove (transition section 2) of the above-mentioned metal band vertical direction, and make upper and lower two layers of polymer film material layer 6 overlap each other; then , hot pressing the above-mentioned stacked materials together, so that the metal current collector and the polymer film material layer 6 are combined together, as shown in Figure 7;

Finally, as shown in Figure 8, the polymer film material layer 6 and its composite current collector are cut into tabs 9 of the battery according to the required size, and the resulting tab conduction section 1 has a length of 10 mm and a thickness of 0.1 mm; The length of the sheet connection section 3 is 30 mm and the thickness is 0.1 mm; the length of the transition section 2 is 5 mm and the thickness is 0.08 mm; the width of the polymer film material layer 6 after hot pressing is 4.5 mm.

The tab 9 made above was used in a battery with a model number of 423482 (4.2mm in thickness, 34mm in width, and 82mm in length), and its impedance was tested. The impedance test result was 28.22mΩ (1KHz);

As a comparison group, a tab with a uniform thickness of 0.08mm, the cell containing the tab has the same sealing effect (that is, the failure rate after the high temperature and high humidity test is equal), but the impedance test result is 30.00mΩ (1KHz) .

The above specific embodiment 1 shows that the sealing problem of the aluminum-plastic packaging film 8 at the tab 9 can be greatly improved after adopting the tab 9 of the present utility model; Under the condition that the sealing effect at the ear 9 is the same, the internal resistance of the battery can be reduced by using the ear 9 of the present invention.

Of course, the above descriptions are only two embodiments of the present invention, and therefore do not limit the scope of protection of the present invention. For example, in the present utility model, the metal strips (positive and negative current collectors) used as the battery lug 9 and the thinning position can adopt different sizes according to the actual application requirements, and the thinning thickness can be achieved according to the required The sealing effect, the internal resistance of the battery and the mechanical strength of the tab 9 are adjusted.

According to the disclosure and teaching of the above specification, those skilled in the art to which the utility model belongs can also change and modify the above-mentioned embodiments. Therefore, the utility model is not limited to the specific embodiments disclosed and described above. Modifications and changes should also fall within the protection scope of the claims of the present invention. 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 (10)

1. soft package lithium ion cell polar ear; Comprise the pole piece linkage section that links to each other with pole piece, with the conduction period of extraneous conducting; And the changeover portion that connects said pole piece linkage section and conduction period; It is characterized in that: the thickness of said changeover portion is less than the thickness of said pole piece linkage section and the thickness of conduction period, and the surface adhesion of said changeover portion has the macromolecule material film layer.

2. soft package lithium ion cell polar ear according to claim 1 is characterized in that: the thickness of said changeover portion is 10%～99% of said pole piece linkage section or conduction period thickness.

3. soft package lithium ion cell polar ear according to claim 1 is characterized in that: said pole piece linkage section, changeover portion and conduction period are one.

4. soft package lithium ion cell polar ear according to claim 3 is characterized in that: the transient mode between said changeover portion and the pole piece linkage section is vertical transition, angled transition or oval transition.

5. soft package lithium ion cell polar ear according to claim 3 is characterized in that: the transient mode between said changeover portion and the conduction period is vertical transition, angled transition or oval transition.

6. soft package lithium ion cell polar ear according to claim 1 and 2 is characterized in that: a side of said changeover portion is provided with thinned region.

7. soft package lithium ion cell polar ear according to claim 1 and 2 is characterized in that: the bilateral of said changeover portion is equipped with thinned region.

8. soft package lithium ion cell polar ear according to claim 1 is characterized in that: said changeover portion surface is coated with the macromolecule material film layer fully.

9. soft package lithium ion cell polar ear according to claim 1 is characterized in that: said changeover portion surface portion is coated with the macromolecule material film layer.

10. lithium ion battery; Comprise electric core and plastic-aluminum packaging film; Electricity core front end is provided with lug, and lug passes from plastic-aluminum packaging film, it is characterized in that: said lug is each described lug of claim 1 to 9; During encapsulation, plastic-aluminum packaging film is positioned on the macromolecule material film layer of changeover portion at the sealing area at lug place.

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