Nickel tab, battery cell and soft package battery

Abstract

The utility model discloses a nickel tab which comprises a nickel metal sheet and tab glue, the nickel metal sheet is bonded by the tab glue, at least one of the nickel metal sheet and the tab glue is provided with a heat conduction layer, and the heat conduction layer is arranged in a connecting area of the tab glue and the nickel metal sheet. According to the utility model, the heat conduction layer is arranged in the connecting area of the nickel metal sheet and the tab adhesive, so that when the nickel tab is packaged, the heating rate in the connecting area can be accelerated, the tab adhesive and the polypropylene layer in the aluminum-plastic film are quickly melted, the condition of insufficient mobility of the tab adhesive is avoided, the defects of crescent marks, wrinkles, convex marks and the like are avoided during pressing, and the reliability of the nickel tab is improved. And the yield of the soft package battery is further improved. In addition, the utility model also discloses a battery cell and a soft package battery.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and particularly relates to a nickel tab, a battery cell and a soft-pack battery. Background Art

[0002] With the development of the new energy industry, the battery cell, as the core component of new energy, is also constantly innovating. Common battery cell structures include square aluminum shell batteries, soft-pack lithium-ion batteries and cylindrical batteries. Generally, the soft-pack lithium-ion battery uses a flexible aluminum-plastic film as the outer shell material. The basic structure of the soft-pack lithium-ion battery is that two aluminum-plastic films are punched and then combined together to form a sealed structure to wrap the bare core structure of the battery cell. Due to the advantages of light weight, high energy density, high safety performance, etc., the soft-pack lithium-ion battery has been widely used.

[0003] Among them, nickel tabs are usually used in soft-pack lithium-ion batteries. However, due to the poor thermal conductivity of nickel tabs and the extremely short time for top-sealing them with aluminum-plastic film, usually two seconds, the nickel tabs cannot quickly obtain enough heat, resulting in insufficient fluidity of the tab glue and the polypropylene layer of the aluminum-plastic film covering the nickel tabs, and it is easy to form defects such as crescent marks, wrinkles, and bumps during pressing, which are not only unbeautiful but also affect the normal use of the soft-pack lithium-ion battery. Increasing the packaging temperature can solve the problem of bumps, but too high packaging temperature will damage the nylon layer of the aluminum-plastic film and affect the service life of the lithium battery. Summary of the Utility Model

[0004] The main purpose of the utility model is to propose a nickel tab, aiming to solve the problem that crescent marks are likely to appear in lithium-ion batteries.

[0005] To achieve the above purpose, the utility model proposes a nickel tab, which includes a nickel metal sheet and tab glue. The tab glue bonds the nickel metal sheet, and at least one of the nickel metal sheet and the tab glue is provided with a heat-conducting layer, and the heat-conducting layer is arranged in the connection area between the tab glue and the nickel metal sheet.

[0006] In some embodiments, the heat-conducting layer covers the nickel metal sheet, the width of the heat-conducting layer is not less than one-third of the width of the tab glue, and the length of the heat-conducting layer is not less than the width of the nickel metal sheet.

[0007] In some embodiments, the heat-conducting layer is a metal layer or a composite material layer.

[0008] In some embodiments, the size of the heat-conducting layer is equal to the size of the connection area.

[0009] In some embodiments, the thickness range of the heat-conducting layer is 10μm - 20μm.

[0010] In some embodiments, the heat-conducting layers are provided on both sides of the nickel metal sheet.

[0011] In some embodiments, the nickel metal sheet is strip-shaped, and the width of the nickel metal sheet located in the connection area is not less than the width of other parts of the nickel metal sheet.

[0012] In some embodiments, the material of the heat-conducting layer is at least one of silver, aluminum, copper, tungsten, and zinc.

[0013] The present utility model further provides a battery cell, including a positive electrode sheet, a negative electrode sheet, a separator, and the nickel tab described in the foregoing embodiments. The nickel tab is welded to the negative electrode sheet, and the separator is disposed between the positive electrode sheet and the negative electrode sheet.

[0014] The present utility model further provides a soft-pack battery, including an aluminum plastic film and the battery cell in the foregoing embodiments. The battery cell is encapsulated in the aluminum plastic film.

[0015] By providing a heat-conducting layer in the connection area between the nickel metal sheet and the ear glue, when the nickel tab is encapsulated, the present utility model can accelerate the heating rate in the connection area, the ear glue and the polypropylene layer in the aluminum plastic film are quickly melted, avoiding the situation of insufficient fluidity of the ear glue, and there will be no defects such as crescent marks, wrinkles, and bumps during pressing, thereby improving the yield of the soft-pack battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a nickel tab in the prior art;

[0017] Figure 2 is a right view of the nickel tab in an embodiment of the present utility model;

[0018] Figure 3 is a schematic structural diagram of the nickel metal sheet in another embodiment of the nickel tab of the present utility model;

[0019] Figure 4 is a right view of the nickel metal sheet in still another embodiment of the nickel tab of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, the solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present utility model.

[0021] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indications will also change accordingly.

[0022] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0023] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those skilled in the art can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0024] The present utility model provides a nickel tab, as Figure 2 shown. The nickel tab includes a nickel metal sheet 10 and a tab adhesive 20. The tab adhesive 20 bonds the nickel metal sheet 10, and at least one of the nickel metal sheet 10 and the tab adhesive 20 is provided with a heat-conducting layer 30. The heat-conducting layer 30 is disposed in the connection region between the tab adhesive 20 and the nickel metal sheet 10.

[0025] The tab, as a bridge for connecting the positive and negative electrodes inside the battery, plays a crucial role in the current conduction, sealing and safety of the battery. As Figure 1 shown, in the prior art, the tab of a soft-pack battery cell is generally composed of two parts, a metal sheet and a film. Among them, the metal sheet generally uses nickel material, and the film uses an adhesive material such as polyacrylate or polyurethane. During the production process, the metal sheet is connected to the current collector through a welding process, and then the film and the polypropylene layer of the aluminum-plastic film are heated and melted under high-temperature conditions and cooled and solidified to achieve the sealing between the aluminum-plastic film and the tab.

[0026] In this embodiment, in order to ensure that the tab glue 20 can melt quickly, the heat-conducting layer 30 is arranged in the connection area between the nickel metal sheet 10 and the tab glue 20 to improve the heat-conducting performance, so as to ensure that the tab glue 20 can absorb enough heat during encapsulation and be melt-mixed with the polypropylene layer of the aluminum-plastic film to complete the encapsulation. The nickel metal sheet 10 has good electrical conductivity, mechanical strength and corrosion resistance, which can ensure the stable performance and long service life of the soft-pack battery. The tab glue 20 plays a role of sealing and fixing in the battery cell and is mainly composed of polymer materials, and its specific composition can vary according to different application requirements and manufacturing processes.

[0027] The heat-conducting layer 30 can be arranged on the tab glue 20, on the nickel metal sheet 10, or on both the tab glue 20 and the nickel metal sheet 10 at the same time. The heat-conducting layer 30 is usually connected to the tab glue 20 by bonding, and the connection method between the heat-conducting layer 30 and the nickel metal sheet 10 depends on the material of the heat-conducting layer 30 used. If a composite material is used as the heat-conducting layer 30, the bonding method is usually adopted, and an appropriate adhesive is used to bond the composite material to the nickel metal sheet 10. At this time, it is necessary to ensure that the adhesive will not dissolve when heated during encapsulation; if a metal material is used as the heat-conducting layer 30, the electroplating or spraying method is usually adopted.

[0028] The shape of the heat-conducting layer 30 can be selected according to actual needs. It can be a regular and continuous graph, such as a rectangle, a circle, a rhombus, etc., or various irregular graphs, or it can be divided into several discontinuous parts and be dispersed in the connection area between the nickel metal sheet 10 and the tab glue 20. After the heat-conducting layer 30 is arranged at a suitable position on the nickel metal sheet 10, the nickel metal sheet 10 and the tab glue 20 are compounded together to form a tab.

[0029] In this embodiment, by arranging the heat-conducting layer 30 in the connection area between the nickel metal sheet 10 and the tab glue 20, when the nickel tab is encapsulated, the heating rate in the connection area can be increased, the tab glue 20 and the polypropylene layer in the aluminum-plastic film can be quickly melted, the situation of insufficient fluidity of the tab glue 20 can be avoided, and defects such as crescent marks, wrinkles, and bumps will not appear during pressing, thereby improving the yield of the soft-pack battery.

[0030] As Figure 3 shown, in some embodiments, the heat-conducting layer 30 covers the nickel metal sheet 10, and the width of the heat-conducting layer 30 is not less than one-third of the width of the tab glue 20, and the length of the heat-conducting layer 30 is not less than the width of the nickel metal sheet 10.

[0031] Exemplarily, Figure 1Taking the nickel tab in [[]] as an example, if the size of the tab adhesive 20 used is a thickness of 0.110 mm × a width of 4.5 mm, the width of the heat conduction layer 30 is usually greater than 1.5 mm. The width of the heat conduction layer 30 can also be set to 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, etc. This is not limited in this embodiment. It can be understood that since the position where the aluminum-plastic film is connected to the nickel tab during the implementation of the battery cell encapsulation is the position where the tab adhesive 20 is located, the width of the heat conduction layer 30 is usually not more than the width of the tab adhesive 20 to avoid waste.

[0032] Regarding the length of the heat conduction layer 30, also taking the Figure 1 nickel tab in [[]] as an example, if the size of the nickel tab is: a width of 6 mm × a thickness of 0.08 mm. Then the length of the heat conduction layer 30 can be 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm... The longest can be equal to the length of the tab adhesive 20. That is, the length of the heat conduction layer 30 can exceed the connection area of the nickel metal sheet 10 and the tab adhesive 20, making the melting speed of the entire tab adhesive 20 with the polypropylene layer of the aluminum-plastic film faster, and further improving the subsequent encapsulation efficiency of the aluminum-plastic film.

[0033] In some embodiments, the heat conduction layer 30 is a metal layer or a composite material layer.

[0034] The heat conduction layer 30 is usually a metal layer or a composite material layer with a thermal conductivity higher than that of nickel. The composite materials include graphite composite materials, carbon fiber composite materials, metal matrix composite materials, etc., which have good thermal conductivity even at high temperatures; the metal materials include silver, aluminum or other metals with a higher thermal conductivity than nickel.

[0035] In some embodiments, the size of the heat conduction layer 30 is equal to the size of the connection area. By controlling the heat conduction layer 30 to completely cover the entire connection area, when encapsulating, the tab adhesive 20 in the connection area is heated more evenly, avoiding the situation where the temperature of some areas is too low, reducing the occurrence of bumps, crescent marks, etc. At the same time, the tab adhesive 20 flows evenly, which can reduce the generation of thermal stress and achieve a better encapsulation effect.

[0036] In some embodiments, the thickness of the heat-conducting layer 30 ranges from 10 μm to 20 μm. The thickness of the heat-conducting layer 30 is controlled to adjust the influence of the heat-conducting layer 30 on the nickel tab. Still referring to the embodiments shown in the figure, if the size of the tab adhesive 20 is 0.110 mm in thickness × 4.5 mm in width, and the size of the nickel metal sheet 10 is 6 mm in width × 0.08 mm in thickness, when the thickness of the heat-conducting layer 30 is less than 10 μm, since the heat-conducting layer 30 is too thin to quickly absorb heat, the effect of increasing the temperature of the tab adhesive 20 is not good; when the thickness of the heat-conducting layer 30 is greater than 20 μm, the heat-conducting layer 30 is too thick, which easily causes abnormalities in the subsequent encapsulation process and reduces the sealing performance of the battery. Therefore, a heat-conducting layer 30 with a thickness of 15 μm is usually selected to avoid the heat-conducting layer 30 being too thick and affecting the aluminum-plastic film encapsulation process while ensuring the melting efficiency of the tab adhesive 20.

[0037] As Figure 4 shown, in some embodiments, heat-conducting layers 30 are provided on both sides of the nickel metal sheet 10. The two heat-conducting layers 30 further accelerate the speed at which the nickel metal sheet 10 absorbs heat, thereby causing the tab adhesive 20 to melt faster. Among them, the two heat-conducting layers 30 can be arranged oppositely, and at the same time, the projections of the two heat-conducting layers 30 on the nickel metal sheet 10 completely overlap, or the projections of the two heat-conducting layers 30 on the nickel metal sheet 10 can be controlled to partially overlap or not overlap at all, which is specifically selected according to requirements. It can be understood that when heat-conducting layers 30 are provided on both sides of the nickel metal sheet 10, the thickness of the heat-conducting layer 30 should be correspondingly reduced to prevent the heat-conducting layer 30 from being too thick and affecting the normal progress of subsequent encapsulation.

[0038] In some embodiments, the nickel metal sheet 10 is strip-shaped, and the width of the nickel metal sheet 10 in the connection area is not less than the width of other parts of the nickel metal sheet 10. The nickel metal sheet 10 can be a regular rectangle, in which case the width of the connection area is the same as that of other parts; the nickel metal sheet 10 can also be an irregular shape. By setting the width of the connection area to be greater than that of other parts, the setting of the heat-conducting layer 30 is more convenient, and the tab adhesive 20 and the polypropylene layer of the aluminum-plastic film at the connection area can absorb more heat, further accelerating the melting speed and avoiding abnormalities during encapsulation.

[0039] In some embodiments, the material of the heat-conducting layer 30 includes at least one of silver, aluminum, copper, tungsten, and zinc. It is relatively simple to provide a heat-conducting layer 30 made of a metal material on the nickel metal sheet 10, and there are many materials with better heat-conducting performance than nickel, which can be selected according to different situations. Exemplarily, aluminum is selected as the material of the heat-conducting layer 30, which has better ductility, low processing difficulty, and can save costs; while copper has a higher price, but excellent heat-conducting performance and good corrosion resistance, which can effectively extend the service life of the tab. It can be understood that the heat-conducting layer 30 can also be made of an alloy composed of the above metal materials.

[0040] The present utility model further provides a battery cell, which includes a positive electrode sheet, a negative electrode sheet, a separator, and the nickel tab in the foregoing embodiments. The nickel tab is welded to the negative electrode sheet, and the separator is disposed between the positive electrode sheet and the negative electrode sheet. The specific structure of the nickel tab refers to the above embodiments. Since the battery cell in this embodiment adopts all the technical solutions of the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated herein one by one.

[0041] The present utility model further provides a soft-pack battery, which includes an aluminum plastic film and the battery cell in the foregoing embodiments. The battery cell is encapsulated in the aluminum plastic film. Specifically, the aluminum plastic film is subjected to pit punching and cutting processes. After the battery cell is placed into the punched pit, the top sealing and side sealing processes are completed, electrolyte is injected, and finally it is sealed, thus realizing the production of the soft-pack battery. Since a heat-conducting layer 30 is provided on the nickel tab, the ear glue 20 is accelerated to dissolve during the encapsulation process, so as to reduce the probability of crescent marks appearing on the soft-pack battery after encapsulation.

[0042] The above are only partial or preferred embodiments of the present utility model. Neither the text nor the drawings can limit the scope of protection of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model under the overall concept of the present utility model, or any direct / indirect application in other related technical fields is included in the scope of protection of the present utility model.

Claims

1. A nickel electrode tab, characterized in that: It comprises a nickel metal sheet and a tab glue, wherein the tab glue is bonded to the nickel metal sheet, and at least one of the nickel metal sheet and the tab glue is provided with a heat conducting layer, and the heat conducting layer is provided in the connection area between the tab glue and the nickel metal sheet.

2. The nickel electrode tab according to claim 1, characterized in that: The heat-conducting layer covers the nickel metal sheet, the width of the heat-conducting layer is not less than one third of the width of the tab glue, and the length of the heat-conducting layer is not less than the width of the nickel metal sheet.

3. The nickel electrode tab according to claim 1, characterized in that: The heat conducting layer is a metal layer or a composite material layer.

4. The nickel electrode tab according to any one of claims 1 to 3, characterized in that: The size of the heat conducting layer is equal to the size of the connecting area.

5. The nickel electrode tab according to claim 4, characterized in that: The thickness of the heat conducting layer is in the range of 10 μm to 20 μm.

6. The nickel electrode tab according to claim 5, characterized in that: The heat conducting layer is disposed on both sides of the nickel metal sheet.

7. The nickel electrode tab according to claim 6, characterized in that: The nickel metal sheet is in the shape of a long strip, and the width of the nickel metal sheet in the connection area is not less than that of other areas of the nickel metal sheet.

8. A battery cell, characterized in that: The invention comprises a positive electrode sheet, a negative electrode sheet, a separator and a nickel electrode tab according to any one of claims 1 to 7, wherein the nickel electrode tab is welded to the negative electrode sheet, and the separator is arranged between the positive electrode sheet and the negative electrode sheet.

9. A soft pack battery, characterized in that: The invention comprises an aluminum-plastic film and the battery core as claimed in claim 8, wherein the battery core is encapsulated in the aluminum-plastic film.

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