Electrode tab protective tape and secondary battery containing the same

Abstract

The present invention relates to an electrode tab protection tape that is attached to an electrode tab manufactured using a thin film material to prevent disconnection due to cracks in the electrode tab and to allow a current to flow continuously, thereby preventing defects in the secondary battery, and a secondary battery including the same. The electrode tab protection tape according to the present invention includes an adhesive layer including an adhesive and a conductive material, and an insulating layer provided on one side of the adhesive layer.

Description

Technical Field

[0001] [Cross-reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0082711 filed on Jun. 24, 2021, and all the contents disclosed in the document of the Korean Patent Application are incorporated herein by reference in their entirety.

[0002] The present invention relates to an electrode tab protection tape and a secondary battery including the same, which is attached to an electrode tab manufactured by applying a thin film material, prevents disconnection defects due to cracks in the electrode tab, and enables a current to flow continuously to prevent malfunction of the secondary battery.

Background Art

[0003] Unlike a primary battery that cannot be charged, a secondary battery means a battery that can be charged and discharged. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, and lithium-ion polymer batteries. Such secondary batteries are used not only in small products such as digital cameras, notebook computers, mobile phones, PDAs, and E-bikes, but also in large products that require high power such as electric vehicles and hybrid vehicles, and in power storage devices for storing surplus generated power and renewable energy and backup power storage devices.

[0004] Such secondary batteries are classified into a pouch type and a can type according to the material of the battery case that houses the electrode assembly. The pouch type houses the electrode assembly in a pouch made of a flexible polymer material with an irregular shape. The can type houses the electrode assembly in a case made of a material such as metal or plastic with a regular shape.

[0005] Figure 1(a) shows a side view of a conventional secondary battery, although the battery case is omitted. Referring to Figure 1, the structure of a typical secondary battery includes an electrode assembly 20 having a structure in which electrodes (negative electrode, positive electrode) and a separator membrane are alternately stacked, and a plurality of electrode tabs (negative electrode tab, positive electrode tab) 30 extending from the electrode assembly 20, with electrode leads (negative electrode lead, positive electrode lead) connected to each of the electrode tabs 30.

[0006] In other words, the electrode assembly 20 is a power generation element in which positive electrode plates and negative electrode plates are sequentially stacked with a separation membrane in between, and multiple positive electrode tabs extend from multiple positive electrode plates, and multiple negative electrode tabs extend from multiple negative electrode plates. Such an electrode assembly 20 is housed in a battery case (not shown), which is a pouch-type outer material, and an electrolyte is injected into it.

[0007] On the other hand, multiple electrode tabs 30 are welded together to the electrode lead using an ultrasonic welding device, and then the multiple electrode tabs 30 welded to the electrode lead are bent into a roughly V-shape. This bent portion A of the electrode tab is sometimes referred to as the V-forming portion. However, with the thinning of the electrode tab 30, cracks or fractures of the electrode tab 30 frequently occur at the bent portion A, as shown in Figure 1(b).

[0008] Figure 1(b) is a bottom view of the bent portion A in Figure 1(a), showing the state in which a crack has occurred in the bent portion A of the electrode tab 30.

[0009] Thus, when cracks occur in the electrode tab 30, the current cannot flow smoothly, resulting in problems such as disconnection and deterioration of the quality of the secondary battery. Therefore, there is a need to develop a product that solves the aforementioned problems. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The present invention was devised to solve the above-mentioned problems, and the object of the present invention is to provide an electrode tab protective tape that adheres to the electrode tab, prevents wire breakage due to cracks in the electrode tab, and prevents defects in the secondary battery by allowing current to flow continuously, and a secondary battery containing the same. [Means for solving the problem]

[0011] The electrode tab protective tape according to the present invention includes an adhesive layer containing an adhesive and a conductive material, and an insulating layer provided on one surface of the adhesive layer.

[0012] The insulating layer may be formed with a larger surface area than the adhesive layer.

[0013] The insulating layer may overlap the adhesive layer so as to protrude along its periphery in the width direction.

[0014] The insulating layer may overlap the adhesive layer so as to protrude along its periphery in both the widthwise and longitudinal directions.

[0015] The secondary battery according to the present invention includes an electrode assembly in which electrodes and a separator membrane are laminated, electrode tabs drawn out from the electrodes, and electrode tab protective tape attached to the electrode tabs, the electrode tab protective tape including an adhesive layer containing an adhesive and a conductive material, and an insulating layer provided on one side of the adhesive layer.

[0016] The insulating layer may be formed with a larger surface area than the adhesive layer.

[0017] The electrode tab protective tape may have the other side of its adhesive layer attached to the electrode tab.

[0018] The electrode tab is bent in a V-shape along the longitudinal direction of the electrode tab, including a bent portion where an inner and outer bend are formed, and the electrode tab protective tape may be attached such that the exposed side of the adhesive layer surrounds the outer bend of the bend.

[0019] The electrode tab protection tape may be attached so as to surround both one surface of the electrode assembly and the outside of the bent portion of the bent part.

[0020] The electrode tab is bent in a V shape along the longitudinal direction of the electrode tab, and includes a bent portion where an inner side of the bend and an outer side of the bend are formed. The electrode tab protection tape may be attached so that the exposed surface of the adhesive layer surrounds the inner side of the bent portion of the bent part.

Effects of the Invention

[0021] The electrode tab protection tape according to the present invention includes an adhesive layer containing an adhesive and a conductive substance, and an insulating layer provided on one surface of the adhesive layer. It is attached to an electrode tab manufactured by applying a thin film material, preventing disconnection due to cracks (Crack) in the electrode tab, enabling current to flow continuously, and preventing defects in the secondary battery.

Brief Description of the Drawings

[0022] [Figure 1] It is a side view of a conventional secondary battery and a bottom view showing a state where cracks have occurred in the electrode tab of the secondary battery. [Figure 2] It is a cross-sectional view showing the electrode tab protection tape according to Example 1 of the present invention. [Figure 3] It is a plan view showing the electrode tab protection tape according to Example 1 of the present invention. [Figure 4] It is a perspective view showing a secondary battery according to Example 2 of the present invention. [Figure 5] It is a view showing a state where the electrode tab protection tape is attached to the secondary battery according to Example 2 of the present invention.

Modes for Carrying Out the Invention

[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention may be embodied in many different forms and is not limited or restricted by the following embodiments.

[0024] To clearly explain the present invention, detailed descriptions of parts not related to the explanation or well-known technologies related thereto that may unnecessarily obscure the gist of the present invention are omitted. When adding reference numerals to the components of each figure in this specification, the same or similar reference numerals are used for the same or similar components throughout the specification.

[0025] In addition, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. In accordance with the principle that the inventor can appropriately define the concept of the terms in order to explain his invention in the best way, they should be construed as meanings and concepts consistent with the technical idea of the present invention.

[0026] Example 1 FIG. 2 is a cross-sectional view showing the electrode tab protection tape according to Example 1 of the present invention. FIG. 3 is a plan view showing the electrode tab protection tape according to Example 1 of the present invention.

[0027] Referring to FIG. 2, the electrode tab protection tape 10 according to Example 1 of the present invention includes an adhesive layer 11 and an insulating layer 12. The composition and structure of the adhesive layer 11 and the insulating layer 12 will be described in detail below.

[0028] The adhesive layer 11 is a layer having an adhesive force so that the electrode tab protection tape 10 according to Example 1 of the present invention can be adhered to other objects. Here, other objects may include not only electrode tabs but also electrode assemblies, electrode leads, etc. As in Example 2 described later, it may be adhered to the electrode tab 30 and the electrode assembly 20 simultaneously (see FIG. 5).

[0029] The adhesive layer 11 of the electrode tab protective tape 10 according to Embodiment 1 of the present invention contains an adhesive to have adhesive strength and at the same time contains a conductive material. That is, the adhesive and the conductive material are mixed to form the adhesive layer 11, so that the adhesive layer 11 adheres to the electrode tab 30, and even if a crack occurs in the electrode tab 30, current can flow through the adhesive layer 11, preventing disconnection. Here, the conductive material means a substance that can conduct electricity, and the present invention is not limited to a specific conductive material, but may include substances that are commonly used in the industry, and may include substances that, when mixed with the adhesive and provided on top of the insulating layer 12, can have both conductivity and adhesiveness.

[0030] The insulating layer 12 can be provided on one surface of the adhesive layer 11 and serve to insulate the electrode tab. Thus, the insulating layer 12 may be made of a material that can perform an insulating function and prevent short circuits. For example, in Example 1 of the present invention, the insulating layer 12 may include unoriented polypropylene resin (CPP, casted polypropylene), which is an unoriented polyolefin resin mainly composed of polypropylene. However, it is not necessarily limited to unoriented polypropylene, and materials such as Teflon® and polyimide, which perform insulating functions and have chemical resistance, may be selected.

[0031] Thus, the electrode tab protection tape 10 according to the present invention includes an adhesive layer 11 containing an adhesive and a conductive substance, and an insulating layer 12 provided on one surface of the adhesive layer 11, and can be attached to an electrode tab made by applying a thin film material, thereby preventing wire breakage due to cracks in the electrode tab and preventing malfunctions of the secondary battery by allowing current to flow continuously.

[0032] Next, the structure of the adhesive layer 11 and the insulating layer 12 will be described with reference to Figure 3. Figure 3 is a plan view showing the electrode tab protective tape 10. More specifically, Figure 3(a) is a plan view showing the case where the areas of the adhesive layer 11 and the insulating layer 12 are the same, and Figures 3(b) and 3(c) show the case where the area of ​​the adhesive layer 11 is smaller than the area of ​​the insulating layer 12.

[0033] Referring to Figure 3(a), the adhesive layer 11 may be provided overlapping one surface of the insulating layer 12 so as to have the same area as the insulating layer 12. That is, when the adhesive layer 11, which contains both adhesive and conductive material, is provided so as to have the same area as the insulating layer 12, it will overlap precisely so that when viewed from a plan view, only one of the adhesive layer 11 or insulating layer 12 will be visible, as shown in Figure 3(a). In this way, when the adhesive layer 11 is provided so as to have the same area as the insulating layer 12, the area of ​​the adhesive layer 11 relative to the insulating layer 12 is increased compared to the electrode tab protective tape 10 shown in Figures 3(b) and 3(c) described later, improving the adhesive strength, and since no step is created between the adhesive layer 11 and the insulating layer 12, it is possible to prevent the protective tape of the electrode tab 30 from lifting or easily separating, and furthermore, it is possible to cover a wide range of cracks, so that wire breakage failure can be effectively prevented.

[0034] Next, referring to Figure 3(c), the adhesive layer 11 may be formed with a smaller area than the insulating layer 12 and overlapping one surface of the insulating layer 12. In particular, the insulating layer 12 may overlap the adhesive layer 11 so as to protrude along the periphery in the width direction (WD).

[0035] The electrode tab protection tape 10 according to Embodiment 1 of the present invention can be manufactured and transported by continuously providing adhesive layers 11 on one side of an insulating layer 12 having a fixed length that is continuously connected along the longitudinal direction (LD), such that the insulating layer 12 protrudes along the periphery of the adhesive layer 11 in the width direction (WD), then winding it up, unwinding it, and cutting off the required length for use. Alternatively, the insulating layer 12 alone can be wound up and transported in a roll, then unwinding it and continuously providing adhesive layers 11, and cutting off the required length for use.

[0036] In this case, the electrode tab protective tape 10 in the form shown in Figure 3(c) can be manufactured by continuously applying an adhesive layer 11 to one side of the insulating layer 12 and then cutting it, thus offering excellent manufacturability and workability, and thus reducing manufacturing costs. Furthermore, when the protective tape for the electrode tab 30 is adhered to the electrode tab 30 or the like, the insulating layer 12 surrounds the adhesive layer 11 containing the conductive material in the width direction (WD), so a superior insulating effect can be expected compared to the electrode tab protective tape 10 shown in Figure 3(a).

[0037] On the other hand, referring to Figure 3(b), the adhesive layer 11 is formed to have a smaller area than the insulating layer 12, and in this case, the insulating layer 12 may overlap the adhesive layer 11 so as to protrude along its periphery in the width direction (WD) and longitudinal direction (LD). That is, when viewed from a planar perspective, the insulating layer 12 may be formed to completely surround the adhesive layer 11. In this case, while effectively preventing disconnection due to cracks in the electrode tab, a superior insulating effect can be expected compared to the electrode tab protective tape 10 in the form shown in Figure 3(c).

[0038] Example 2 Figure 4 is a perspective view showing a secondary battery according to Embodiment 2 of the present invention. Figure 5 shows the state in which electrode tab protective tape is attached to the secondary battery according to Embodiment 2 of the present invention.

[0039] Example 2 of the present invention differs from Example 1 in that it is a secondary battery that includes the electrode tab protective tape of Example 1.

[0040] We will omit as much as possible the content that is common to Example 1 and focus on explaining the differences in Example 2. In other words, it is self-evident that any content that is not explained in Example 2 is necessary and should be considered as part of Example 1.

[0041] Referring to Figures 4 and 5, the secondary battery 1 according to Embodiment 2 of the present invention includes an electrode assembly 20, electrode tabs 30, and electrode tab protective tape 10. The secondary battery may also include a battery case, electrolyte, etc., but these are not shown separately in Figure 4 and Figure 5, which will be described later.

[0042] The electrode assembly 20 is a laminated structure of electrodes and a separation membrane, and more specifically, a positive electrode, a separation membrane, a negative electrode, and a separation membrane are laminated. Various forms can be selected, such as a jelly roll type formed by winding a long sheet, a stack type in which unit cells cut to a certain size are laminated, and a stack folding type in which unit cells are laminated and a separation membrane is folded.

[0043] On the other hand, the electrode tabs 30 are drawn out from the electrodes, with a positive electrode tab drawn out from the positive electrode and a negative electrode tab drawn out from the negative electrode. The electrode tabs 30 may be drawn out by cutting the electrodes, or they may be drawn out by being separately joined to the electrodes.

[0044] The secondary battery 1 according to Embodiment 2 of the present invention includes an electrode tab protection tape 10 attached to the electrode tab 30, the electrode tab protection tape 10 including an adhesive layer 11 containing an adhesive and a conductive substance, and an insulating layer 12 provided on one surface of the adhesive layer 11. The insulating layer 12 may include, but is not limited to, a material selected from unoriented polypropylene resin (CPP, cast polypropylene), Teflon®, or polyimide, and a variety of materials with chemical resistance may be selected. Furthermore, the insulating layer 12 may be formed with a larger area than the adhesive layer 11. Other aspects of the configuration of the electrode tab protection tape 10 and its effects can be understood in the same way as in Embodiment 1.

[0045] On the other hand, the electrode tab protection tape 10 has an insulating layer 12 on one side of the adhesive layer 11, and the other side of the adhesive layer 11 may be attached to the electrode tab 30. The position and method of attaching the electrode tab protection tape 10 to the secondary battery 1 will be described in detail below with reference to Figure 5.

[0046] First, Figure 5(a) shows the electrode assembly 20 and the electrode tab 30. The electrode tab 30 can be bent in a V-shape along its longitudinal direction, and may include a bent portion 31 in which an inner bend 31a and an outer bend 31b are formed.

[0047] Referring to Figures 5(b) and 5(c), the electrode tab protective tape 10 according to Embodiment 2 of the present invention may be attached such that the exposed surface of the adhesive layer 11 surrounds the outer bend 31b of the bend 31. That is, one surface of the adhesive layer 11 is provided with an insulating layer 12, and the other surface of the adhesive layer 11 that does not have the insulating layer 12 is exposed, and the other surface of the adhesive layer 11 may be attached so as to surround the outer bend 31b of the bend 31 of the electrode tab 30. As a result, even if a crack occurs in the outer bend 31b which is fragile to cracks and breaks, a break in the wire will not occur, and current will be able to pass through the adhesive layer 11 which contains a conductive material.

[0048] Furthermore, the electrode tab protective tape 10 may be attached so as to surround both one surface of the electrode assembly 20 and the outer bent portion 31b of the bent portion 31. One surface of the electrode assembly 20 may refer to one of several surfaces formed on the electrode assembly 20 whose normal direction corresponds to the direction of the outer bent portion 31b. In this way, when the electrode tab protective tape 10 is attached to both the electrode tab 30 and one surface of the electrode assembly 20, additional adhesive strength and support strength can be ensured.

[0049] On the other hand, the electrode tab protection tape 10 may be attached so that the exposed surface of the adhesive layer 11 surrounds the inner bend 31a of the bent portion 31. That is, since there is a good chance that cracks may occur in the electrode tab 30 not only on the outer bend 31b of the bent portion 31 but also on the inner bend 31a, the electrode tab protection tape 10 can be attached to the inner bend 31a to effectively prevent disconnection of the secondary battery. Of course, the electrode tab protection tape 10 can be attached to both the inner bend 31a and the outer bend 31b simultaneously. [Explanation of Symbols]

[0050] 1 Secondary battery 10 Electrode tab protective tape 11 Adhesive layer 12 Insulating layer 20 Electrode assembly 30 electrode tabs 31 Bend section 31a inside bend 31b Bend outside WD electrode tab protective tape width direction Longitudinal direction of LD electrode tab protective tape

Claims

1. An adhesive layer containing an adhesive and a conductive material; and An electrode tab protective tape comprising an insulating layer provided on one surface of the adhesive layer, The electrode tab protective tape has the other side of the adhesive layer attached to the bent portion of the electrode tab. An electrode tab protective tape characterized in that the insulating layer has a larger surface area than the adhesive layer.

2. The aforementioned insulating layer is The electrode tab protection tape according to claim 1, characterized in that it overlaps so as to protrude along the periphery in the width direction of the adhesive layer.

3. The aforementioned insulating layer is The electrode tab protection tape according to claim 1, characterized in that it overlaps so as to protrude along the periphery of the adhesive layer in the width direction and longitudinal direction.

4. An electrode assembly in which electrodes and a separation membrane are stacked; An electrode tab drawn out from the electrode; and Includes electrode tab protective tape that is attached to the electrode tab, The electrode tab protective tape is An adhesive layer containing an adhesive and a conductive material; and The adhesive layer includes an insulating layer provided on one surface of the adhesive layer, The electrode tab protective tape has the other side of the adhesive layer attached to the electrode tab. The insulating layer is formed with a larger area than the adhesive layer. The electrode tab is The electrode tab is bent in a V-shape along its longitudinal direction, and includes a bent portion where an inner and outer bent portion are formed. The electrode tab protective tape is A secondary battery characterized in that the exposed surface of the adhesive layer is attached so as to surround the outer surface of the bend in the bent portion.

5. The electrode tab protective tape is The secondary battery according to claim 4, characterized in that it is attached so as to surround both one surface of the electrode assembly and the outer surface of the bend of the bent portion.

6. The electrode tab protective tape is The secondary battery according to claim 4, characterized in that the exposed surface of the adhesive layer is attached so as to surround the inside of the bend of the bent portion.

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