Battery cell and battery module including same

Abstract

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 corresponding to the sealing portion on at least one of an upper portion and a lower portion of the electrode lead, the lead film including a first adhesive layer and a second adhesive layer, and a moisture removal layer located between the first adhesive layer and the second adhesive layer, the moisture removal layer including a getter material.

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 increases, 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 cars, and hybrid electric cars.

[0004] Such secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is housed in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is housed in a pouch-type case made of an aluminum laminate sheet, according to the shape of the battery case. 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 electrode and the negative electrode and is capable of charging and discharging, and is classified into a jelly roll type in which a separator is interposed between a long sheet-type positive electrode and a negative electrode coated with an active material and wound up, and a stack type in which a plurality of 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, there has been a problem that the amount of gas generated inside a battery cell increases as the energy density of the battery cell increases. 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. Even if the battery cell includes a separate venting portion for discharging gas, moisture may penetrate into the battery cell from the venting portion, which may cause a side reaction that may degrade the performance of the battery cell and lead to further gas generation. Thus, there is an increasing demand for the development of a battery cell that can prevent moisture from the outside of the battery cell from penetrating into the battery cell while improving the ability to discharge gas generated inside 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 flowing 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 the problems described above, and problems not mentioned will be clearly understood by those skilled in the art from the present 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 an 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 in 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 including a first adhesive layer and a second adhesive layer, a moisture removal layer being located between the first adhesive layer and the second adhesive layer, and the moisture removal layer including a getter material.

[0010] The getter material is 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 removing layer may further comprise polypropylene.

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

[0015] The moisture removal layer may include 0.01 wt % to 80 wt % of the getter material based on the total weight of the moisture removal 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 is 67×10 ―16 ~201×10 ―16 (mol·m / (m 2 ·s·Pa))( 20~60 barrer ) It could be.

[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 is 67×10 ―16 ~201×10 ―16 (mol·m / (m 2 ·s·Pa))( 20~60 bar ) It could be.

[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 on an upper portion of the electrode lead, and the second lead film being positioned on a lower portion of 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 be in contact with each other.

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

[0027] According to an embodiment of the present invention, by providing a battery cell including an electrode lead having a multilayered lead film attached thereto, 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 inside of the battery cell.

[0028] The effects of the present invention are not limited to the effects 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 description of the drawings]

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not limited by the drawings. In the drawings, thicknesses are enlarged to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

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

[0034] Furthermore, throughout the specification, a "plan view" means a view of the subject part viewed from above, and a "cross-sectional view" means a view of a vertical cross-section of the subject part viewed 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, and the same or similar description may be applied to the rear side of the battery module.

[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 the present 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] In addition, the electrode assembly 110 may include a jelly roll type (wound type), a laminate type (stack type), or a composite type (lamination / folding 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] 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 part 250. In addition, the lead film 400 is located in a portion corresponding to the sealing part 250 on at least one of the upper and lower parts of the electrode lead 300. Thus, the lead film 400 can prevent a short circuit from occurring in the electrode lead 300 during heat fusion, and can improve the sealing property between the sealing part 250 and the electrode lead 300.

[0043] Also, the lead film 400 may have a width wider than the electrode lead 300. The lead film 400 may have a length longer than the sealing portion 250 and shorter than the electrode lead 300. As a result, the lead film 400 does not interfere with the electrical connection of the electrode lead 300 and can prevent the side of the electrode lead 300 from being exposed to the outside. In this specification, the width of the lead film 400 means the maximum value of the distance between one end and the other end of the lead film 400 based on a perpendicular direction to the protruding direction of the electrode lead 300, and the width of the electrode lead 300 means the maximum value of the distance between one end and the other end of the electrode lead 300 based on a perpendicular direction to the protruding direction of the electrode lead 300. The length of the lead film 400 means the maximum value of the 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 means the maximum value of the 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 means 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, and the first lead film 401 may be located on the upper side of the electrode lead 300, and the second lead film 402 may be located on the lower side of the electrode lead 300. In this case, the electrode lead 300 may be fused with the sealing part 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 part 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] Thus, the lead film 400 can prevent the side surface of the electrode lead 300 from being exposed to the outside, and can 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 an outer surface of the electrode lead 300, and the second adhesive layer 430 may be adhered to an 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] As an example, each of the first adhesive layer 410 and the second adhesive layer 430 may 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 makes it easier to prevent the interface between the first adhesive layer 410 and the electrode lead 300 from peeling off when the internal pressure of the battery cell 100 increases.

[0051] The gas permeability of the first adhesive layer 410 at 60° C. 67×10 ―16 ~201×10 ―16 (mol·m / (m 2 ·s·Pa))( 20~60 bar ) ,or 100×10 ―16 ~134×10 ―16 (mol·m / (m 2 ·s·Pa))( 30~40 bar ) For example, the carbon dioxide permeability of the first adhesive layer 410 may satisfy the above-mentioned range. In addition, the gas permeability of the first adhesive layer 410 may satisfy the above-mentioned range at 60° C., based on a thickness of 200 μm. 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 at 60° C. 67×10―16 ~201×10 ―16 (mol·m / (m 2 ·s·Pa))( 20~60 bar ) ,or 100×10 ―16 ~134×10 ―16 (mol·m / (m 2 ·s·Pa))( 30~40 bar ) For example, the carbon dioxide permeability of the second adhesive layer 430 may satisfy the above-mentioned range. In addition, the gas permeability of the second adhesive layer 430 may satisfy the above-mentioned range at 60° C., based on a thickness of 200 μm. 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 contact 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] Thus, the lead film 400 can prevent the side surface of the electrode lead 300 from being exposed to the outside, and can 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, film deformation 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, film deformation 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 using a gas adsorption action by a chemically activated metal film. For example, the getter material is calcium oxide (CaO), lithium chloride (LiCl), silica (SiO 2 ), barium oxide (BaO), barium (Ba), and calcium (Ca). As 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, since the moisture removal layer 420 contains a getter material, it minimizes the permeability of moisture flowing from the outside of the battery cell 100 into the inside of the battery cell 100, while having high gas permeability, it can more easily discharge gas generated inside the battery cell 100 to the outside.

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

[0061] Also, the moisture removing 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 removing layer 420. By adjusting the content of the getter material in the moisture removing layer 420 within the above-mentioned 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, the permeation of moisture flowing from the outside of the battery cell 100 to the inside of the battery cell 100 can be more easily prevented, and the adhesive strength between the first adhesive layer 410 and the second adhesive layer 430 can be more easily prevented from being reduced, and the interface between the moisture removing layer 420 and the first adhesive layer 410 or the second adhesive layer 430 can be more easily prevented from peeling off when the internal pressure of the battery cell 100 increases due to a decrease in the adhesive strength between the first adhesive layer 410 and the second adhesive layer 430. The problem of quality degradation due to damage such as film deformation during the manufacturing process can also be more easily prevented.

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

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

[0064] The above-mentioned battery module and the battery pack including the same may be applied to various devices. Such devices may be means of transportation such as electric bicycles, electric cars, hybrid cars, etc. However, the present invention is not limited thereto, and the battery module and the battery pack including the same may be applied to various devices that can use the battery module, and these are also within the scope of the present invention.

[0065] Although a preferred embodiment of the present invention has been described in detail above, it goes without saying that the scope of the present invention is not limited thereto, and 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 Lead 400 Lead Film 401 1st Lead Film 402 2nd 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 an 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 part; a lead film located at a portion corresponding to the sealing portion at 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 as measured by ASTM F2476-20 is 67×10 at 60° C. ―１６ ~201 x 10 ―１６ (mol m / (m ２ .s.Pa) (20 to 60 barrer), The moisture removal layer includes a getter material in an amount of 30 wt % to 70 wt % based on the total weight of the moisture removal layer, the getter material comprises at least one of lithium chloride, silica, barium oxide, and barium; or The getter material has a metal organic framework structure, A battery cell, wherein the moisture removing layer has a thickness of 60 μm or more.

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

3. 10. 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 comprises a polyolefin-based 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 comprises 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 resistance of the battery cell 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 the upper portion 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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