Battery cell and battery module including the battery cell

Abstract

A battery cell according to an embodiment of the present invention includes: a battery housing in which an electrode assembly is mounted on a receiving portion, and the battery housing includes a sealing portion having a structure in which an outer periphery is sealed; an electrode lead electrically connected to an electrode connector included in the electrode assembly and protruding outward from the battery housing via the sealing portion; and a lead film located in a portion corresponding to the sealing portion in at least one of an upper and lower portion of the electrode lead, wherein the lead film includes a first adhesive layer and a second adhesive layer, a dehumidifying layer is located between the first adhesive layer and the second adhesive layer, and the dehumidifying layer includes an absorbent material.

Description

Technical Field

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

[0002] This disclosure relates to a battery cell and a battery module including the battery cell, and more specifically, to a battery cell and a battery module including the battery cell that can suppress moisture penetration into the battery cell while improving the external discharge of gases generated inside the battery cell. Background Technology

[0003] With technological advancements and increasing demand for mobile devices, the need for secondary batteries as an energy source is rapidly growing. Specifically, secondary batteries are attracting significant interest not only as a power source for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also as a power source for propulsion systems such as electric bicycles, electric vehicles, and hybrid vehicles.

[0004] Based on the shape of the battery casing, these secondary batteries are classified as follows: cylindrical and prismatic batteries in which the battery assembly is contained in a cylindrical or prismatic metal can, and pouch batteries in which the battery assembly is contained in a pouch-shaped casing of aluminum laminates. Here, the battery assembly contained in the battery casing is a power element that includes a positive electrode, a negative electrode, and a separator placed between the positive and negative electrodes and is capable of charging and discharging. It is classified as a wound core type in which long sheet-type positive and negative electrodes coated with active material are wound with a separator placed between them, and a stacked type in which multiple positive and negative electrodes are sequentially stacked with a separator placed between them.

[0005] Specifically, among these batteries, pouch batteries, which are stacked or stacked / folded battery assemblies contained in pouch battery housings made of aluminum laminates, are increasingly being used due to their low manufacturing cost, light weight, and ease of modification.

[0006] However, with the increase in battery cell energy density in recent years, a problem has emerged: the amount of gas generated inside the battery cell has also increased. Specifically, if the gas generated inside the battery cell is not easily vented, exhaust gas may occur within the battery cell due to gas generation. Furthermore, even if a separate exhaust section is included in the battery cell, moisture can still seep into the battery cell through this section, which may lead to battery performance degradation and the generation of additional gas due to the resulting side reactions. Therefore, there is an increasing need to develop battery cells that can prevent external moisture from seeping into the battery cell while improving the external exhaust of gas generated inside the battery cell. Summary of the Invention

[0007] Technical issues

[0008] This disclosure is designed to address the problems of the prior art, and therefore aims to provide a battery cell capable of suppressing external moisture penetration into the battery cell while improving the external discharge of gases generated inside the battery cell, as well as a battery module including the battery cell.

[0009] The purposes to be addressed in this disclosure are not limited to those described above, and those skilled in the art will clearly understand from this specification and the accompanying drawings that purposes not mentioned herein may be found elsewhere.

[0010] Technical solution

[0011] In one aspect of this disclosure, a battery cell is provided, the battery cell comprising: a battery housing having a receiving portion for mounting an electrode assembly and a sealing portion formed by sealing its outer periphery; an electrode lead electrically connected to an electrode connector included in the electrode assembly and protruding beyond the battery housing via the sealing portion; and a lead film located in a portion corresponding to the sealing portion of at least one of an upper and lower portion of the electrode lead, wherein the lead film includes a first adhesive layer and a second adhesive layer, and a dehumidifying layer is located between the first adhesive layer and the second adhesive layer, and the dehumidifying layer includes an air-absorbing material.

[0012] The getter material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silicon dioxide (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca).

[0013] Getter materials can have a metal-organic framework (MOF) structure.

[0014] The dehumidification layer may also include polyolefin-based resins.

[0015] The dehumidification layer may also include polypropylene.

[0016] The dehumidification layer can have a thickness of 60μm or more.

[0017] Based on the total weight of the dehumidification layer, the dehumidification layer may include 0.01% to 80% by weight of absorbent material.

[0018] The first adhesive layer may include a polyolefin-based resin.

[0019] The first adhesive layer may include polypropylene treated with maleic anhydride (MAH).

[0020] The first adhesive layer can have a gas permeability of 20 to 60 bar at 60°C.

[0021] The first adhesive layer can have a thickness of 60 μm or more.

[0022] The second adhesive layer may include a polyolefin-based resin.

[0023] The second adhesive layer can have a gas permeability of 20 to 60 bar at 60°C.

[0024] The second adhesive layer can have a thickness of 60 μm or more.

[0025] The first adhesive layer can adhere to the outer surface of the electrode lead, and the second adhesive layer can adhere to the inner surface of the sealing portion.

[0026] The lead film may include a first lead film and a second lead film, wherein the first lead film may be located on the upper part of the electrode lead and the second lead film may be located on the lower part of the electrode lead.

[0027] The end of the first adhesive layer included in the first lead film can contact the end of the first adhesive layer included in the second lead film.

[0028] In another aspect of this disclosure, a battery module is also provided, which includes the aforementioned battery cell.

[0029] Technical effect

[0030] According to embodiments, this disclosure provides a battery cell including electrode leads and a battery module including the electrode cell, wherein a multilayer lead film is attached to the electrode leads, thereby improving the external emission of gases generated inside the battery cell and suppressing moisture penetration into the battery cell.

[0031] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from this specification and the accompanying drawings the effects not mentioned herein. Attached Figure Description

[0032] Figure 1 This is a top view showing a battery cell according to an embodiment of the present disclosure.

[0033] Figure 2 It shows that it is included Figure 1 A three-dimensional view of the electrode leads and lead film in the battery cell.

[0034] Figure 3 It is shown Figure 2 An exploded three-dimensional view of the electrode leads and lead film.

[0035] Figure 4 It shows that it is included Figure 1 A cross-sectional view of the lead film in a battery cell. Detailed Implementation

[0036] In the following description, various embodiments of this disclosure will be detailed with reference to the accompanying drawings to facilitate implementation by those skilled in the art. This disclosure can be implemented in various different forms and is not limited to the embodiments described herein.

[0037] For clarity of this disclosure, parts unrelated to the specification have been omitted, and identical or similar parts are given the same reference numerals throughout the specification.

[0038] Furthermore, since the dimensions and thicknesses of the various components shown in the accompanying drawings are arbitrarily represented for ease of description, this disclosure is not necessarily limited to the drawings. Thicknesses have been exaggerated to clearly illustrate the various layers and regions in the drawings. Additionally, the thicknesses of some layers and regions have been exaggerated in the drawings for ease of explanation.

[0039] Additionally, throughout the specification, when a section "includes" a component, it means that other components may also be included, rather than excluding other components, unless otherwise mentioned.

[0040] Additionally, throughout the instruction manual, when "top view" is mentioned, it means viewing the target portion from above, while when "section view" is mentioned, it means viewing the target portion from the side with a vertical cut section.

[0041] In the following text, a battery module according to an embodiment of the present disclosure will be described. However, the description will be based on the front surface of the battery module, but is not limited thereto, and the same or similar content may be described in the case of the rear surface.

[0042] Figure 1 This is a top view showing a battery cell according to an embodiment of the present disclosure.

[0043] Reference Figure 1 According to this embodiment, the battery cell 100 includes a battery housing 200, electrode leads 300, and lead film 400.

[0044] The battery housing 200 includes a receiving portion 210 in which the electrode assembly 110 is mounted and a sealing portion 250 formed by sealing its outer periphery. The sealing portion 250 can be sealed by heat, laser, or the like. The battery housing 200 may be a laminate including a resin layer and a metal layer. More specifically, the battery housing 200 may be made of a laminate and may include an outer resin layer forming the outermost layer, a barrier metal layer to prevent material penetration, and an inner resin layer for sealing.

[0045] Furthermore, the electrode assembly 110 may have a core-type (wound), laminated, or composite (laminated / folded) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed between them.

[0046] The electrode lead 300 and lead film 400 will be described in detail below.

[0047] Figure 2 It shows that it is included Figure 1 A three-dimensional view of the electrode leads and lead film in the battery cell. Figure 3 It is shown Figure 2 An exploded three-dimensional view of the electrode leads and lead film.

[0048] Reference Figure 1 and Figure 2 The electrode lead 300 is electrically connected to the electrode connector 115 included in the electrode assembly 110 and protrudes beyond the battery housing 200 via a sealing portion 250. Additionally, a lead film 400 is located at a portion corresponding to the sealing portion 250 in at least one of the upper and lower portions of the electrode lead 300. Therefore, the lead film 400 can improve the sealing performance of the sealing portion 250 and the electrode lead 300, while preventing short circuits in the electrode lead 300 during thermal melting.

[0049] Additionally, the lead film 400 may have a wider width than the electrode lead 300. The lead film 400 may have a longer length than the sealing portion 250, but a shorter length than the electrode lead 300. Therefore, the lead film 400 can prevent the side surfaces of the electrode lead 300 from being exposed without affecting the electrical connection of the electrode lead 300. In this specification, the width of the lead film 400 refers to the maximum distance between one end of the lead film 400 and the other end in a direction perpendicular to the protrusion direction of the electrode lead 300, and the width of the electrode lead 300 refers to the maximum distance between one end of the electrode lead 300 and the other end in a direction perpendicular to the protrusion direction of the electrode lead 300. The length of the lead film 400 refers to the maximum distance between one end of the lead film 400 and the other end in the protrusion direction of the electrode lead 300, and the length of the sealing portion 250 refers to the maximum distance between one end of the sealing portion 250 and the other end in the protrusion direction of the electrode lead 300. The length of electrode lead 300 refers to the maximum distance between one end and the other end of electrode lead 300 based on the protruding direction of electrode lead 300.

[0050] See Figure 2 and Figure 3The lead film 400 may include a first lead film 401 and a second lead film 402. The first lead film 401 may be located above the electrode lead 300, while the second lead film 402 may be located below the electrode lead 300. In this case, the electrode lead 300 may be fused together with the sealing portion 250 while positioned 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 together with the sealing portion 250 by heat, laser, etc. Here, the two ends of the first lead film 401 and the two ends of the second lead film 402 may be in contact with each other. In other words, as... Figure 2 As shown, the two ends of the first lead film 401 and the two ends of the second lead film 402 can be integrated with each other. For example, the two ends of the first lead film 401 and the two ends of the second lead film 402 can be integrated with each other by melting with heat, laser, etc.

[0051] Therefore, the lead film 400 can prevent the side surface of the electrode lead 300 from being exposed to the outside, while improving the sealing performance of the sealing portion 250 and the electrode lead 300.

[0052] The lead film 400 will be described in detail below.

[0053] Figure 4 It shows that it is included Figure 1 A cross-sectional view of the lead film in a battery cell.

[0054] Reference Figure 1 and Figure 4 The lead film 400 may include a first adhesive layer 410, a dehumidifying layer 420, and a second adhesive layer 430. Here, the dehumidifying 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 multilayer structure in which the first adhesive layer 410, the dehumidifying layer 420, and the second adhesive layer 430 are stacked in sequence.

[0055] Additionally, refer to Figure 1 and Figure 4 The first adhesive layer 410 can adhere to the outer surface of the electrode lead 300, and the second adhesive layer 430 can adhere to the inner surface of the sealing portion 250. That is, the first adhesive layer 410 may include a material that easily adheres to the electrode lead 300, and the second adhesive layer 430 may include a material that easily adheres to the sealing portion 250.

[0056] For example, the first adhesive layer 410 and the second adhesive layer 430 may each comprise a polyolefin-based resin. The polyolefin-based resin may include polypropylene, polyethylene, polyvinyl difluoroethylene (PVDF), or mixtures thereof. More specifically, the first adhesive layer 410 may comprise polypropylene treated with maleic anhydride (MAH). Therefore, the first adhesive layer 410 can adhere more easily to the electrode leads 300 made of metallic material, and interface delamination between the first adhesive layer 410 and the electrode leads 300 can be more easily prevented when the internal pressure of the battery cell 100 increases.

[0057] At 60°C, the gas permeability of the first adhesive layer 410 can be between 20 and 60 bar, or between 30 and 40 bar. For example, the carbon dioxide permeability of the first adhesive layer 410 can meet the above range. Furthermore, based on the thickness of the first adhesive layer 410 being 200 μm, the gas permeability can meet the above range at 60°C. If the gas permeability of the first adhesive layer 410 meets the above range, the gas generated inside the battery cell can be discharged more effectively.

[0058] At 60°C, the gas permeability of the second adhesive layer 430 can be between 20 and 60 bar, or between 30 and 40 bar. For example, the carbon dioxide permeability of the second adhesive layer 430 can meet the above range. Furthermore, based on the thickness of the second adhesive layer 430 being 200 μm, the gas permeability can meet the above range at 60°C. If the gas permeability of the second adhesive layer 430 meets the above range, the gas generated inside the battery cell can be discharged more effectively.

[0059] In this specification, gas permeability can be measured using ASTM F2476-20.

[0060] Additionally, refer to Figure 3 and Figure 4 When the lead film 400 includes a first lead film 401 and a second lead film 402, the end of the first adhesive layer 410 included in the first lead film 401 can contact the end of the first adhesive layer 410 included in the second lead film 402. In other words, as Figure 2 As shown, the two ends of the first lead film 401 and the two ends of the second lead film 402 are respectively melted together, and the ends of the first adhesive layer 410 of the first lead film 401 and the ends of the first adhesive layer 40 of the second lead film 402 can be integrated with each other.

[0061] Therefore, the lead film 400 can prevent the side surface of the electrode lead 300 from being exposed, while improving the sealing performance of the sealing portion 250 and the electrode lead 300.

[0062] The first adhesive layer 410 can have a thickness of 60 μm or more. If the thickness of the first adhesive layer 410 meets the above range, it is easier to prevent the film from deforming during the manufacturing process.

[0063] The second adhesive layer 430 can have a thickness of 60 μm or more. If the thickness of the second adhesive layer 430 meets the above range, it is easier to prevent the film from deforming during the manufacturing process.

[0064] Additionally, the dehumidification layer 420 may include an air-absorbing material. Here, the air-absorbing material can refer to a material capable of expelling gases by absorbing gases through a chemically activated metal membrane. For example, the air-absorbing material may include at least one of calcium oxide (CaO), lithium chloride (LiCl), silicon dioxide (SiO2), barium oxide (BaO), barium (Ba), and calcium (Ca). As another example, the air-absorbing material may have a metal-organic framework (MOF) structure. However, the air-absorbing material is not limited to this and may include all kinds of materials generally classified as air-absorbing materials.

[0065] Therefore, the dehumidifying layer 420, which includes a gas-absorbing material, can minimize moisture infiltration into the battery cell 100 from the outside and allows gas to be easily discharged to the outside due to its high gas permeability.

[0066] In addition to the air-absorbing material, the desiccant layer 420 may also include a polyolefin-based resin. The polyolefin-based resin may include polypropylene, polyethylene, polydifluoroethylene (PVDF), or mixtures thereof.

[0067] Furthermore, based on the total weight of the dehumidifying layer 420, the dehumidifying layer 420 may include 0.01% to 80% by weight, or 30% to 70% by weight, of getter material. Therefore, by adjusting the content of the getter material within the aforementioned range, the dehumidifying layer 420 can be more easily adjusted, depending on the use of the lead film 400, to control the moisture permeability of moisture introduced into the battery cell 100 from the outside and the gas permeability of gas generated inside the battery cell 100 and discharged to the outside. Additionally, it is easier to prevent moisture from permeating into the battery cell 100 from the outside, and it is easier to prevent the interface between the dehumidifying layer 420 and the first adhesive layer 410 or the second adhesive layer 430 from peeling due to reduced adhesion to the first adhesive layer 410 and the second adhesive layer 430 when the internal pressure of the battery cell 100 increases. It is also easier to prevent quality degradation due to damage during the manufacturing process, such as film deformation.

[0068] The dehumidification layer 420 can have a thickness of 60 μm or more. If the thickness of the dehumidification layer 420 meets the above range, it is easier to prevent the membrane from deforming during the manufacturing process.

[0069] Additionally, a battery module according to another embodiment of this disclosure includes the aforementioned battery cells. Furthermore, one or more battery modules according to this embodiment can be encapsulated in a battery pack housing to form a battery pack.

[0070] The aforementioned battery module and battery pack including the battery module can be applied to various devices. These devices can be vehicles such as electric bicycles, electric vehicles, hybrid vehicles, etc., but this disclosure is not limited thereto, and this disclosure can be applied to various devices that can use battery modules and battery packs including the battery modules, which are also within the scope of this disclosure.

[0071] This disclosure has been described in detail. However, it should be understood that while the detailed description and specific examples indicate preferred embodiments of this disclosure, they are given by way of example only, as various variations and modifications within the scope of this disclosure will be apparent to those skilled in the art based on the detailed description.

Claims

1. A battery cell, the battery cell comprising: a battery case having a receiving portion in which an electrode assembly is installed, and a sealing portion formed by sealing an outer circumference of the receiving portion; an electrode lead wire electrically connected to an electrode tab included in the electrode assembly and protruding outside the battery case via the sealing portion; and a lead wire film in at least one of an upper portion and a lower portion of the electrode lead wire, the lead wire film being located in a portion corresponding to the sealing portion, wherein the lead wire film includes a first adhesive layer and a second adhesive layer, and a dehumidification layer is located between the first adhesive layer and the second adhesive layer, the first adhesive layer has a carbon dioxide permeability of 20 barrer to 60 barrer at 60°C according to ASTM F2476-20, the dehumidification layer includes 30% to 70% by weight of a getter material based on a total weight of the dehumidification layer, the getter material includes at least one of lithium chloride LiCl, silicon dioxide SiO2, barium oxide BaO, and barium Ba, and the dehumidification layer has a thickness of 60 µm or more. 2.The battery cell of claim 1, the getter material has a structure of a metal organic framework MOF. wherein 3.The battery cell of claim 1, the dehumidification layer further includes a polyolefin-based resin. wherein 4.The battery cell of claim 3, the polyolefin-based resin includes polypropylene. wherein 5.The battery cell of claim 3, the polyolefin-based resin includes polypropylene, polyethylene, polyvinyl difluoride PVDF, or a mixture thereof. wherein 6.The battery cell of claim 1, the first adhesive layer includes a polyolefin-based resin. wherein 7.The battery cell of claim 1, the first adhesive layer includes polypropylene treated with maleic anhydride MAH. wherein, 8.The battery cell of claim 1, the first adhesive layer has a thickness of 60 µm or more. wherein 9.The battery cell of claim 1, the second adhesive layer includes a polyolefin-based resin. wherein, 10.The battery cell of claim 1, the second adhesive layer has a gas permeability of 20 barrer to 60 barrer at 60°C. wherein 11.The battery cell of claim 1, the second adhesive layer has a thickness of 60 µm or more. wherein 12.The battery cell of claim 1, the first adhesive layer is adhered to an outer surface of the electrode lead wire, and wherein, the second adhesive layer is adhered to an inner surface of the sealing portion. 13.The battery cell of claim 1, the lead wire film includes a first lead wire film and a second lead wire film, wherein the first lead wire film is located in the upper portion of the electrode lead wire, and the second lead wire film is located in the lower portion of the electrode lead wire. 14.The battery cell of claim 13, an end portion of the first adhesive layer included in the first lead wire film is in contact with an end portion of the first adhesive layer included in the second lead wire film. wherein 15.The battery cell of claim 1, ​ wherein The lead film has a width that is wider than the electrode lead, and the lead film has a length that is longer than the sealing portion, but the lead film has a length that is shorter than the electrode lead.

16. A battery module comprising the battery cell according to any one of claims 1 to 15.

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