Battery cell and battery module including the same

Abstract

To provide a battery cell.SOLUTION: A battery cell according to an embodiment of the present invention, contains: a housing part to which an electrode assembly is attached; a battery case containing a sealing part that is formed by sealing an outer periphery of the housing part; an electrode lead that is electrically connected with an electrode tub contained in the electrode assembly, and is projected to an outside of the battery case while passing through the sealing part; and a lead film that is positioned to a part corresponded to the sealing part in at least one of an upper part and a lower part of the electrode lead. The lead film contains a first adhesion layer and a second adhesion layer, and a water removal layer is positioned to between the first adhesion layer and the second adhesion layer. The water removal layer contains a getter material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims priority to Korean Patent Application No. 10-2021-0051923, filed on April 21, 2021.

[0002] The present invention relates to a battery cell and a battery module including the same, and more specifically to a battery cell that improves the ability to discharge gas generated inside the battery cell to the outside while suppressing the penetration of moisture flowing into the battery cell, and a battery module including the same. [Background technology]

[0003] As technological development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing. In particular, secondary batteries are attracting much attention as energy sources for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, as well as for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

[0004] Depending on the shape of the battery case, such secondary batteries can be divided into cylindrical batteries and prismatic batteries in which an electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries in which an electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet. Here, the electrode assembly housed in the battery case is a power generating element that includes a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes and is capable of charging and discharging. It can be divided into a jelly roll type in which a long sheet-type positive electrode and a negative electrode coated with an active material are wound with a separator interposed between them, and a stacked type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them.

[0005] Among these, pouch-type batteries, which have a structure in which a stacked or stacked / folded electrode assembly is housed in a pouch-type battery case made of an aluminum laminate sheet, are increasingly being used due to their low manufacturing cost, light weight, and ease of deformation.

[0006] However, in recent years, as the energy density of battery cells has increased, the amount of gas generated inside the battery cells has also increased. In particular, if the gas generated inside the battery cell is not smoothly discharged, the battery cell may experience a venting phenomenon due to gas generation. Furthermore, even if the battery cell includes a separate vent for discharging gas, moisture may penetrate into the battery cell through the vent, causing side reactions that may degrade the performance of the battery cell and lead to further gas generation. Therefore, there is a growing demand for the development of a battery cell that can improve the ability to discharge gas generated inside the battery cell to the outside while preventing moisture from penetrating into the battery cell. Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a battery cell that improves the ability to discharge gas generated inside the battery cell to the outside while suppressing the penetration of moisture into the battery cell, and a battery module including the same.

[0008] The problems to be solved by the present invention are not limited to those described above, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. [Means for solving the problem]

[0009] According to one aspect of the present invention, a battery cell includes a battery case including a receiving portion in which an electrode assembly is attached and a sealing portion formed by sealing the outer periphery of the receiving portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing portion; and a lead film located at a portion of at least one of an upper portion and a lower portion of the electrode lead corresponding to the sealing portion, wherein the lead film includes a first adhesive layer and a second adhesive layer, and a moisture removal layer is located between the first adhesive layer and the second adhesive layer, and the moisture removal layer includes a getter material.

[0010] The getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO 2 ), barium oxide (BaO), barium (Ba), and calcium (Ca).

[0011] The getter material may have a metal organic framework (MOF) structure.

[0012] The moisture-removing layer may further contain a polyolefin resin.

[0013] The moisture removal layer may further comprise polypropylene.

[0014] The thickness of the moisture-removing layer may be 60 μm or more.

[0015] The moisture-removing layer may include 0.01 wt % to 80 wt % of the getter material based on the total weight of the moisture-removing layer.

[0016] The first adhesive layer may include a polyolefin resin.

[0017] The first adhesive layer may include polypropylene treated with maleic anhydride (MAH).

[0018] The gas permeability of the first adhesive layer may be 20 to 60 barrers at 60°C.

[0019] The first adhesive layer may have a thickness of 60 μm or more.

[0020] The second adhesive layer may include a polyolefin resin.

[0021] The gas permeability of the second adhesive layer may be 20 to 60 barrers at 60°C.

[0022] The second adhesive layer may have a thickness of 60 μm or more.

[0023] The first adhesive layer may be adhered to an outer surface of the electrode lead, and the second adhesive layer may be adhered to an inner surface of the sealing portion.

[0024] The lead film may include a first lead film and a second lead film, the first lead film being positioned above the electrode lead, and the second lead film being positioned below the electrode lead.

[0025] An end of the first adhesive layer included in the first lead film and an end of the first adhesive layer included in the second lead film may contact each other.

[0026] A battery module according to another aspect of the present invention includes the above-described battery cells. [Effects of the Invention]

[0027] According to an embodiment of the present invention, by providing a battery cell including an electrode lead to which a multilayered lead film is attached, and a battery module including the same, it is possible to improve the ability to discharge gas generated inside the battery cell to the outside and to suppress the penetration of moisture flowing into the battery cell.

[0028] The effects of the present invention are not limited to those described above, and effects not mentioned will be clearly understood by those skilled in the art from the present specification and the accompanying drawings. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is a top view of a battery cell according to one embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of an electrode lead and a lead film included in the battery cell of FIG. 1. [Figure 3] FIG. 3 is an exploded perspective view of the electrode lead and the lead film of FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view of a lead film included in the battery cell of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0030] DETAILED DESCRIPTION OF THE INVENTION The present invention may, however, be embodied in various different forms and should not be construed as limited to the embodiments set forth herein.

[0031] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0032] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the sake of convenience, and the present invention is not limited by the drawings. In the drawings, thicknesses are exaggerated to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the sake of convenience.

[0033] Furthermore, throughout the specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, and that other components may also be included, unless otherwise specified.

[0034] Furthermore, throughout the specification, a "plan view" means a view of the target part viewed from above, and a "cross-sectional view" means a view of the target part cut vertically from the side.

[0035] Hereinafter, a battery module according to an embodiment of the present invention will be described. However, the description will be made based on the front side of the battery module, but the description is not limited thereto, and the same or similar description may be applied to the rear side.

[0036] FIG. 1 is a top view of a battery cell according to one embodiment of the present invention.

[0037] Referring to FIG. 1, a battery cell 100 according to this embodiment includes a battery case 200, an electrode lead 300, and a lead film 400.

[0038] The battery case 200 includes a sealing portion 250 in which the electrode assembly 110 is attached to the receiving portion 210 and the outer periphery is sealed. The sealing portion 250 may be sealed by heat or a laser. The battery case 200 may be made of a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 may be made of a laminate sheet and may include an outer resin layer forming the outermost shell, a barrier metal layer that prevents the passage of substances, and an inner resin layer for sealing.

[0039] The electrode assembly 110 may also have a jelly roll type (wound type), a stack type, or a composite type (stacked / folded type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0040] The following description will focus on the electrode lead 300 and the lead film 400.

[0041] FIG. 2 is a perspective view of an electrode lead and a lead film included in the battery cell of FIG. 1, and FIG. 3 is an exploded perspective view of the electrode lead and the lead film of FIG.

[0042] 1 and 2, the electrode lead 300 is electrically connected to the electrode tab 115 included in the electrode assembly 110 and protrudes to the outside of the battery case 200 through the sealing portion 250. In addition, the lead film 400 is located at a portion corresponding to the sealing portion 250 on at least one of the upper and lower portions of the electrode lead 300. As a result, the lead film 400 can prevent a short circuit from occurring in the electrode lead 300 during heat sealing and can improve the sealing between the sealing portion 250 and the electrode lead 300.

[0043] In addition, the lead film 400 may have a width wider than that of the electrode lead 300. The lead film 400 may have a length longer than that of the sealing portion 250 but shorter than that of the electrode lead 300. As a result, the lead film 400 does not interfere with the electrical connection of the electrode lead 300 and prevents the side surfaces of the electrode lead 300 from being exposed to the outside. In this specification, the width of the lead film 400 refers to the maximum distance between one end and the other end of the lead film 400 based on a direction perpendicular to the protruding direction of the electrode lead 300, and the width of the electrode lead 300 refers to the maximum distance between one end and the other end of the electrode lead 300 based on a direction perpendicular to the protruding direction of the electrode lead 300. The length of the lead film 400 refers to the maximum distance between one end and the other end of the lead film 400 based on the protruding direction of the electrode lead 300, and the length of the sealing portion 250 refers to the maximum distance between one end and the other end of the sealing portion 250 based on the protruding direction of the electrode lead 300. The length of the electrode lead 300 refers to the maximum distance between one end and the other end of the electrode lead 300 based on the protruding direction of the electrode lead 300 .

[0044] 2 and 3, the lead film 400 includes a first lead film 401 and a second lead film 402. The first lead film 401 may be located on top of the electrode lead 300, and the second lead film 402 may be located on bottom of the electrode lead 300. In this case, the electrode lead 300 may be fused with the sealing portion 250 while being located between the first lead film 401 and the second lead film 402. The first lead film 401 and / or the second lead film 402 may be fused with the sealing portion 250 by heat, a laser, or the like. Here, both ends of the first lead film 401 and both ends of the second lead film 402 may be in contact with each other. In other words, as shown in FIG. 2, both ends of the first lead film 401 and both ends of the second lead film 402 may be integrated with each other. For example, both ends of the first lead film 401 and both ends of the second lead film 402 may be fused with each other by heat, a laser, or the like.

[0045] As a result, the lead film 400 can prevent the side surfaces of the electrode lead 300 from being exposed to the outside, and can also improve the sealing performance between the sealing portion 250 and the electrode lead 300 .

[0046] The lead film 400 will be described in detail below.

[0047] FIG. 4 is a cross-sectional view of a lead film included in the battery cell of FIG.

[0048] 1 and 4, the lead film 400 may include a first adhesive layer 410, a moisture removal layer 420, and a second adhesive layer 430. Here, the moisture removal layer 420 may be located between the first adhesive layer 410 and the second adhesive layer 430. In other words, the lead film 400 may have a multi-layer structure in which the first adhesive layer 410, the moisture removal layer 420, and the second adhesive layer 430 are laminated in order.

[0049] 1 and 4, the first adhesive layer 410 may be adhered to the outer surface of the electrode lead 300, and the second adhesive layer 430 may be adhered to the inner surface of the sealing portion 250. That is, the first adhesive layer 410 may include a material that can be easily adhered to the electrode lead 300, and the second adhesive layer 430 may include a material that can be easily adhered to the sealing portion 250.

[0050] For example, the first adhesive layer 410 and the second adhesive layer 430 may each include a polyolefin-based resin. The polyolefin-based resin may include polypropylene, polyethylene, polyvinyldifluoride (PVDF), or two or more of these. More specifically, the first adhesive layer 410 may include polypropylene treated with maleic anhydride (MAH). This allows the first adhesive layer 410 to more easily adhere to the electrode lead 300 made of a metal material, and more easily prevents peeling at the interface between the first adhesive layer 410 and the electrode lead 300 when the internal pressure of the battery cell 100 increases.

[0051] The gas permeability of the first adhesive layer 410 may be 20 to 60 barrers, or 30 to 40 barrers, at 60°C. For example, the carbon dioxide permeability of the first adhesive layer 410 may satisfy the above-mentioned range. Furthermore, the gas permeability of the first adhesive layer 410, based on a thickness of 200 μm, may satisfy the above-mentioned range at 60°C. When the gas permeability of the first adhesive layer 410 satisfies the above-mentioned range, gas generated inside the battery cell can be more effectively discharged.

[0052] The gas permeability of the second adhesive layer 430 may be 20 to 60 barrers, or 30 to 40 barrers, at 60°C. For example, the carbon dioxide permeability of the second adhesive layer 430 may satisfy the above-mentioned range. Furthermore, the gas permeability of the second adhesive layer 430 having a thickness of 200 μm may satisfy the above-mentioned range at 60°C. When the gas permeability of the second adhesive layer 430 satisfies the above-mentioned range, gas generated inside the battery cell can be more effectively discharged.

[0053] As used herein, gas permeability may be measured by ASTM F2476-20.

[0054] 3 and 4, when the lead film 400 includes a first lead film 401 and a second lead film 402, an end of the first adhesive layer 410 included in the first lead film 401 and an end of the first adhesive layer 410 included in the second lead film 402 may be in contact with each other. In other words, as shown in FIG. 2, both ends of the first lead film 401 and both ends of the second lead film 402 may be fused to each other, and the end of the first adhesive layer 410 of the first lead film 401 and the end of the first adhesive layer 410 of the second lead film 402 may be integrated with each other.

[0055] As a result, the lead film 400 can prevent the side surfaces of the electrode lead 300 from being exposed to the outside, and can also improve the sealing performance between the sealing portion 250 and the electrode lead 300 .

[0056] The thickness of the first adhesive layer 410 may be 60 μm or more. When the thickness of the first adhesive layer 410 satisfies the above range, deformation of the film occurring during the manufacturing process can be more easily prevented.

[0057] The thickness of the second adhesive layer 430 may be 60 μm or more. When the thickness of the second adhesive layer 430 satisfies the above range, deformation of the film occurring during the manufacturing process can be more easily prevented.

[0058] The moisture removal layer 420 may also include a getter material. Here, the getter material refers to a material that can be evacuated by adsorbing gases through a chemically activated metal film. For example, the getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca). For another example, the getter material may have a metal organic framework (MOF) structure. However, the getter material is not limited thereto and may include all types of materials generally classified as getter materials.

[0059] As a result, the moisture removal layer 420 contains a getter material, which minimizes the penetration of moisture from the outside of the battery cell 100 into the inside of the battery cell 100, and also has high gas permeability, which makes it easier to discharge gas generated inside the battery cell 100 to the outside.

[0060] The moisture removal layer 420 may contain a polyolefin resin in addition to the getter material, which may include polypropylene, polyethylene, polyvinyl difluoride (PVDF), or two or more of these.

[0061] The moisture removal layer 420 may contain the getter material in an amount of 0.01 wt % to 80 wt %, or 30 wt % to 70 wt %, based on the total weight of the moisture removal layer 420. By adjusting the content of the getter material in the moisture removal layer 420 within the above range, the permeability of moisture flowing from the outside of the battery cell 100 to the inside of the battery cell 100 and the permeability of gas generated inside the battery cell 100 being discharged to the outside can be more easily adjusted according to the application of the lead film 400. Furthermore, moisture permeation from the outside of the battery cell 100 to the inside of the battery cell 100 can be more easily prevented. Also, a problem of peeling at the interface between the moisture removal layer 420 and the first adhesive layer 410 or the second adhesive layer 430 due to a decrease in adhesive strength between the first adhesive layer 410 and the second adhesive layer 430 when the internal pressure of the battery cell 100 increases can be more easily prevented. A problem of quality degradation due to damage such as film deformation during the manufacturing process can also be more easily prevented.

[0062] The thickness of the moisture removal layer 420 may be 60 μm or more. When the thickness of the moisture removal layer 420 satisfies the above range, deformation of the film during the manufacturing process can be more easily prevented.

[0063] A battery module according to another aspect of the present invention includes the above-described battery cell. Meanwhile, one or more battery modules according to this embodiment may be packaged in a pack case to form a battery pack.

[0064] The above-described battery module and a battery pack including the same may be applied to various devices. Such devices may be transportation means such as electric bicycles, electric vehicles, and hybrid vehicles, but the present invention is not limited thereto and may be applied to various devices that can use a battery module and a battery pack including the same, which also fall within the scope of the present invention.

[0065] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it goes without saying that various modifications and improvements made by those skilled in the art using the basic concept of the present invention as claimed in the claims also fall within the scope of the present invention. [Explanation of symbols]

[0066] 100 battery cells 110 Electrode assembly 115 Electrode tab 200 Battery Case 210 Storage area 250 sealing part 300 electrode leads 400 lead film 401 First Lead Film 402 Second Lead Film 410 1st adhesive layer 420 Moisture removal layer 430 Second adhesive layer

Claims

1. a battery case including a receiving portion in which the electrode assembly is mounted and a sealing portion formed by sealing the outer periphery of the receiving portion; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding to the outside of the battery case through the sealing portion; a lead film located at a portion corresponding to the sealing portion on at least one of an upper portion and a lower portion of the electrode lead, the lead film includes a first adhesive layer and a second adhesive layer, and a moisture-removing layer is positioned between the first adhesive layer and the second adhesive layer; The carbon dioxide permeability of the first adhesive layer measured by ASTM F2476-20 is 67 x 10 at 60°C. ―１６ ~201 x 10 ―１６ (mol m / (m ２ s Pa)) (20 to 60 barrers), The moisture-removing layer includes a getter material in an amount of 30 wt % to 70 wt % based on the total weight of the moisture-removing layer, the getter material comprises at least one of lithium chloride, silica, barium oxide, and barium; or A battery cell, wherein the getter material has a metal organic framework structure.

2. The battery cell according to claim 1 , wherein the moisture-removing layer further comprises a polyolefin-based resin.

3. The battery cell of claim 1 , wherein the moisture removal layer further comprises polypropylene.

4. The battery cell according to claim 1 , wherein the first adhesive layer includes a polyolefin resin.

5. 10. The battery cell of claim 1, wherein the first adhesive layer comprises maleic anhydride treated polypropylene.

6. The battery cell according to claim 1 , wherein the first adhesive layer has a thickness of 60 μm or more.

7. The battery cell according to claim 1 , wherein the second adhesive layer includes a polyolefin resin.

8. The carbon dioxide permeability of the second adhesive layer is 67×10 at 60° C. ―１６ ~201 x 10 ―１６ (mol m / (m ２ 2. The battery cell according to claim 1, wherein the tensile strength is 20 to 60 barrers.

9. The battery cell according to claim 1 , wherein the second adhesive layer has a thickness of 60 μm or more.

10. the first adhesive layer is adhered to an outer surface of the electrode lead; The battery cell of claim 1 , wherein the second adhesive layer is adhered to an inner surface of the sealing portion.

11. the lead film includes a first lead film and a second lead film; the first lead film is located on top of the electrode lead, The battery cell according to claim 1 , wherein the second lead film is located below the electrode lead.

12. The battery cell of claim 11 , wherein an end of the first adhesive layer included in the first lead film and an end of the first adhesive layer included in the second lead film are in contact with each other.

13. A battery module comprising the battery cell according to any one of claims 1 to 12.

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