Battery cell and battery module including the same

Abstract

The present invention relates to a battery cell including a gas exhaust part to which a sealing pattern with weak sealing strength is applied, and a battery module including the same. [Solution] A battery cell according to one embodiment of the present invention includes a battery case including a sealing portion in which an electrode assembly is mounted in a storage portion and whose outer periphery is sealed; and an electrode lead that is electrically connected to an electrode tab included in the electrode assembly and protrudes outward from the battery case through the sealing portion, the sealing portion including a gas exhaust portion, and a portion of the sealing portion where the gas exhaust portion is not located is formed with a first sealing pattern, and the gas exhaust portion is formed with a second sealing pattern, the first sealing pattern and the second sealing pattern being different from each other.

Description

[Technical Field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0136429, filed October 14, 2021, and Korean Patent Application No. 10-2022-0127087, filed October 5, 2022, and all contents disclosed in the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery cell and a battery module including the same, and more particularly to a battery cell including a gas exhaust part to which a sealing pattern with weak sealing strength is applied, and a battery module including the same. [Background technology]

[0003] With technological development and increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are attracting much attention as an energy source 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] These secondary batteries are classified into cylindrical 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 aluminum laminate sheet, depending on the shape of the battery case. The electrode assembly housed in the battery case is composed of a positive electrode, a negative electrode, and a separator membrane interposed between the positive and negative electrodes, and is classified into a jelly roll type, in which a long sheet-type positive electrode and negative electrode coated with active material are wound up with a separator membrane interposed between them as a charge-discharge capable power generating element, and a stack type, in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator membrane interposed between them.

[0005] Among these, pouch-type batteries, which have a structure in which a stack-type or stack / fold-type electrode assembly is housed in a pouch-type battery case made of an aluminum laminate sheet, are gradually increasing in use due to their low manufacturing cost, small weight, and easy modification.

[0006] However, as the energy density of battery cells has increased in recent years, the amount of gas generated inside the battery cells has also increased. Conventional battery cells do not include components that allow gas generated inside the battery cell to escape, which can lead to venting. In particular, when conventional battery cells experience venting, gas escapes from areas with weak sealing. This gas is flammable and can heat adjacent cells, leading to fires and explosions.

[0007] Therefore, there is an increasing need to develop a battery cell that can effectively discharge gas when a venting phenomenon occurs in the battery cell, while also guiding the gas discharge direction in a specific direction to improve safety. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION An object of the present invention is to provide a battery cell including a gas exhaust part to which a sealing pattern having a weak sealing strength is applied, and a battery module including the same.

[0009] The problems that the present invention aims to solve are not limited to those described above, and problems not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from this specification and the accompanying drawings. [Means for solving the problem]

[0010] A battery cell according to one embodiment of the present invention includes a battery case including a sealing portion in which an electrode assembly is mounted in a housing and whose outer periphery is sealed; and an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding outward from the battery case through the sealing portion, wherein the sealing portion includes a gas exhaust portion, and a portion of the sealing portion where the gas exhaust portion is not located is formed with a first sealing pattern, and the gas exhaust portion is formed with a second sealing pattern, and the first sealing pattern and the second sealing pattern are different from each other.

[0011] The first sealing pattern may have a pattern of repeated indentations and protrusions along the length of the sealing portion, and the second sealing pattern may have a pattern of repeated indentations and protrusions along the width of the sealing portion.

[0012] The first sealing pattern and the second sealing pattern may have the same interval between the recessed portion and the protruding portion.

[0013] A distance between the recessed portion and the protruding portion of the second sealing pattern may be greater than a distance between the recessed portion and the protruding portion of the first sealing pattern.

[0014] The gas exhaust portion may be located around the outer periphery of the sealing portion where the electrode lead is located.

[0015] The gas exhaust portion may be located in a portion of the outer periphery where the electrode leads are located, where the electrode leads are not located.

[0016] The sealing strength of the gas exhaust portion may be less than the sealing strength of the sealing portion.

[0017] A battery module according to another embodiment of the present invention may include the above-described battery cells, and the battery cells may be stacked in a direction in which the gas exhaust portion is adjacent to a bottom surface.

[0018] In the battery cell, the gas exhaust portion may be formed in the sealing portion below the electrode lead. [Effects of the Invention]

[0019] According to an embodiment, the present invention provides a battery cell including a gas exhaust part to which a sealing pattern with weak sealing strength is applied, and a battery module including the same. When a venting phenomenon occurs in a battery cell, gas is effectively exhausted and the gas exhaust direction is guided in a specific direction, thereby improving safety.

[0020] 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 this specification and the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a top view of a battery cell according to an embodiment of the present invention. [Figure 2] 2(a) is an enlarged view of one end of the battery cell of FIG. 1, and FIG. 2(b) is a cross-sectional view taken along the cutting line A-A' or the cutting line B-B' of FIG. 2(a). [Figure 3] FIG. 3(a) is a diagram showing a sealing pattern of the sealing portion of FIG. 2(a), and FIG. 3(b) is a diagram showing a sealing pattern of the gas exhaust portion of FIG. 2(a). [Figure 4] 10 is an enlarged view of one end of a battery cell according to a comparative example. [Figure 5] 5 is a cross-sectional view taken along the line a-a' in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE INVENTION The present invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

[0023] In order to clearly describe the present invention, portions not necessary for the description will be omitted and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0024] Furthermore, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown. In order to clearly show multiple layers and regions in the drawings, thicknesses are exaggerated. In the drawings, the thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0025] Furthermore, throughout the specification, when a part "comprises" other elements, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0026] Also, throughout the specification, "in a plane" means a view of the subject matter as seen from above, and "in cross section" means a view of the subject matter as seen from the side across a vertical cross section.

[0027] Hereinafter, a battery cell according to an embodiment of the present invention will be described.

[0028] FIG. 1 is a top view of a battery cell according to an embodiment of the present invention.

[0029] The battery cell 100 according to one embodiment of the present invention includes a battery case 200 having a sealing portion 250 in which an electrode assembly 110 is mounted in a receiving portion 210 and the outer periphery is sealed; and an electrode lead 300 that is electrically connected to an electrode tab included in the electrode assembly 110 and protrudes outward from the battery case 200 through the sealing portion 250.

[0030] The battery case 200 may be 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 be configured with an outer resin layer forming the outermost layer, a barrier metal layer that prevents penetration of materials, and an inner resin layer for sealing.

[0031] The electrode assembly 110 may have a jelly roll type (wound type), stack type (layered type), or composite type (stack / folded type) structure. More specifically, the electrode assembly 110 may include a positive electrode, a negative electrode, and a separator disposed therebetween.

[0032] The electrode lead 300 is electrically connected to an electrode tab (not shown) included in the electrode assembly 110 and protrudes outward from the battery case 200 through the sealing part 250. The lead film 400 is located on at least one of the upper and lower parts of the electrode lead 300, in a portion corresponding to the sealing part 250.

[0033] Therefore, the lead film 400 can prevent a short circuit from occurring in the electrode lead 300 when heat-sealed or press-sealed together with the sealing part 250 and can also improve the sealing performance between the sealing part 250 and the electrode lead 300 .

[0034] Hereinafter, a sealing portion of a battery cell according to an embodiment of the present invention will be described, focusing on one end of the battery cell. However, the present invention is not limited to this, and the same or similar content can be applied to the opposite end of the battery cell.

[0035] Fig. 2(a) is an enlarged view of one end of the battery cell of Fig. 1, Fig. 2(b) is a cross-sectional view taken along line A-A' or line B-B' of Fig. 2(a), Fig. 3(a) is a view showing the sealing pattern of the sealing part of Fig. 2(a), and Fig. 3(b) is a view showing the sealing pattern of the gas exhaust part of Fig. 2(a).

[0036] 1 and 2(a), in the battery cell 100 according to this embodiment, the sealing unit 250 includes a gas exhaust unit 250V. That is, the gas exhaust unit 250V may be formed to replace a part of the sealing unit 250. That is, the gas exhaust unit 250V may be inserted into a part of the sealing unit 250.

[0037] More specifically, in the sealing unit 250, the gas exhaust unit 250V may be located around the outer periphery where the electrode lead 300 is located. That is, the gas exhaust unit 250V may be located in the sealing unit 250 that seals the outer periphery where the electrode lead 300 is located.

[0038] In a typical battery cell 100, the part of the sealing part 250 where the sealing strength is weakest is the part where the electrode lead 300 is located. However, in the present invention, the gas exhaust part 250V is formed around the outer periphery where the electrode lead 300 is located, so that gas that is exhausted when the internal pressure of the battery cell 100 increases can be prevented from being exhausted to the part of the sealing part 250 where the electrode lead 300 is located.

[0039] For example, the gas exhaust unit 250V may be located in a portion of the periphery where the electrode lead 300 is located, but not where the electrode lead 300 is located. That is, the gas exhaust unit 250V may be located in a sealing unit 250 that seals the portion of the periphery where the electrode lead 300 is located, but not where the electrode lead 300 is located. However, the location of the gas exhaust unit 250V is not limited thereto, and the gas exhaust unit 250V may be formed in a position taking into consideration the direction in which gas exhaust is to be guided.

[0040] 2(a), gas discharged when the internal pressure of the battery cell 100 increases is not discharged through the portion of the sealing part 250 where the electrode lead 300 is located, but is discharged through the gas discharge part 250V located in a portion other than the portion where the electrode lead 300 is located. In other words, the gas discharge part 250V can guide the discharge direction of gas discharged when the internal pressure of the battery cell 100 increases in a specific direction.

[0041] Furthermore, in the battery cell 100 of this embodiment, the sealing strength of the gas discharge unit 250V may be smaller than the sealing strength of the sealing unit 250. As a result, when the internal pressure of the battery cell 100 increases, the gas discharge unit 250V can be damaged prior to the sealing unit 250. In other words, when the internal pressure of the battery cell 100 increases, the gas discharge unit 250V is damaged before the sealing unit 250, and the gas discharge unit 250V can serve as a passage for discharging gas.

[0042] 2(a), a portion of the sealing portion 250 where the gas exhaust portion is not located may be formed with a first sealing pattern, and the gas exhaust portion 250V may be formed with a second sealing pattern. Here, the first sealing pattern and the second sealing pattern may be different. Here, the sealing pattern may refer to a sealing area having a certain pattern.

[0043] More specifically, the first sealing pattern of the sealing portion 250 and the second sealing pattern of the gas discharge portion 250V may be patterns in which indentations and protrusions are repeated in different directions. For example, as shown in FIG. 2(b), the first sealing pattern has indentations and protrusions repeated along the length direction of the sealing portion 250 (cutting line A-A'), and the second sealing pattern has indentations and protrusions repeated along the width direction of the sealing portion 250 (cutting line B-B').

[0044] 2 and 3(a), the sealing portion 250 may have a first sealing pattern in which indentations and protrusions are repeated along the length of the sealing portion 250. In this case, the first sealing pattern may receive a bending load along the direction of the pattern of the sealing portion 250, as shown in FIG. 3(a). That is, the first sealing pattern may receive a bending load in the width direction of the repeatedly formed indentations or protrusions. As a result, the sealing portion 250 having the first sealing pattern may receive a bending load only in part, resulting in relatively high sealing strength.

[0045] 2 and 3(b), the gas discharge portion 250V may have a second sealing pattern that is indented and protruded along the width direction of the sealing portion 250. In this case, the second sealing pattern may receive a bending load in a direction perpendicular to the direction of the sealing portion 250's pattern extension, as shown in FIG. 3(b). That is, the second sealing pattern may receive a bending load in the length direction of the indented or protruded portion. As a result, the gas discharge portion 250V having the second sealing pattern may receive a bending load across the entire indented or protruded portion, which may result in a relatively weaker sealing strength.

[0046] As a result, in the battery cell 100 of this embodiment, the sealing strength of the gas discharge unit 250V having the second sealing pattern may be smaller than the sealing strength of the sealing unit 250 having the first sealing pattern. That is, when the internal pressure of the battery cell 100 increases, the gas discharge unit 250V breaks before the sealing unit 250, and the gas discharge unit 250V guides the direction of gas discharge and serves as a gas discharge passage.

[0047] In addition, this embodiment does not include a separate member for gas exhaust, and has the advantage of forming a gas exhaust portion 250V with different sealing strengths simply by changing the sealing pattern, thereby simplifying the manufacturing process and reducing manufacturing costs.

[0048] For example, the first sealing pattern and the second sealing pattern may have the same intervals between the recessed portions and the protruding portions.

[0049] Therefore, the first and second sealing patterns are different only in the direction of pattern formation and have the same pattern spacing, which makes the manufacturing process easier and improves process efficiency.

[0050] As another example, a distance between the recessed portion and the protruding portion of the second sealing pattern may be greater than a distance between the recessed portion and the protruding portion of the first sealing pattern.

[0051] As a result, the sealing strength of the gas discharge part 250V having the second sealing pattern is reduced, that is, the gas discharge part 250V is broken more quickly when the internal pressure of the battery cell 100 increases, and the gas can be effectively discharged to the outside of the battery cell 100.

[0052] However, the interval between the recessed portion and the protruding portion of the first sealing pattern and the second sealing pattern is not limited to this, and may be formed at various intervals other than those described above.

[0053] A battery module according to another embodiment of the present invention may include the above-described battery cell 100. In particular, in the battery module, the battery cells 100 may be stacked in a direction such that the side surface on which the electrode lead 300 is not located faces the bottom surface. Here, the battery cells 100 may be stacked in a direction such that the gas exhaust portion 250V is adjacent to the bottom surface. For example, the battery cells 100 may be stacked in a direction such that the gas exhaust portion 250V is located below the electrode lead 300. That is, in the battery cell 100, the gas exhaust portion 250V may be formed in the sealing portion 250 below the electrode lead 300.

[0054] As a result, in this embodiment, the gas exhaust portion 250V of the battery cell 100 is located adjacent to the bottom surface, and gas exhausted through the gas exhaust portion 250V when the internal pressure of the battery cell 100 increases can be exhausted toward the bottom surface. That is, in this embodiment, gas exhausted from some of the battery cells 100 is exhausted toward the bottom surface, which can minimize damage to adjacent battery cells 100 caused by high-temperature flammable gas exhausted from the battery cell 100 and can also effectively delay heat propagation to adjacent battery cells 100.

[0055] Meanwhile, one or more battery modules according to this embodiment may be packaged in a pack case to form a battery pack.

[0056] The battery module and the battery pack including the same can be applied to various devices, including transportation means such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and can be applied to various devices that can use the battery module and the battery pack including the same, which also fall within the scope of the present invention.

[0057] Fig. 4 is an enlarged view of one end of a battery cell according to a comparative example, and Fig. 5 is a cross-sectional view taken along the line a-a' in Fig. 4.

[0058] 4, the battery cell 10 according to the comparative example includes an electrode assembly 11 mounted in a battery case 20 and a sealing portion 25 formed by sealing the outer periphery of the battery case 20. The battery cell 10 includes an electrode lead 30 that is electrically connected to an electrode tab included in the electrode assembly 11 and protrudes outward from the battery case 20 through the sealing portion 25.

[0059] 1 to 3, the battery cell 10 according to the comparative example does not have a separate sealing pattern formed on the sealing portion 25. That is, in the battery cell 10 according to the comparative example, the entire sealing portion 25 may be sealed in a flat form.

[0060] 5, in the case of the battery cell 10 according to the comparative example, since a separate sealing pattern is not formed in the sealing portion 25, a bending load is applied in the thickness direction of the battery cell 10, and it can be seen that the sealing portion 25 is damaged. In particular, the portion of the sealing portion 25 where the electrode lead 30 is located, which is the portion with the weakest sealing strength, may be damaged. Furthermore, the portion where the electrode lead 30 is located is located very close to the electrode lead of an adjacent battery cell, and high-temperature flammable gas emitted through the damaged portion of the sealing portion 25 can rapidly heat the adjacent battery cell. As a result, there is a problem that heat transfer between battery cells 10 is more likely to occur in a battery module including the battery cell 10 according to the comparative example.

[0061] 1 to 3, the battery cell 100 according to this embodiment can more easily discharge gas through the gas discharge unit 250 V. At the same time, the gas is discharged in a direction previously guided by the gas discharge unit 250 V, which prevents heat transfer between adjacent battery cells 100 and provides an advantage of further improving safety.

[0062] 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 various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0063] 10, 100 battery cells 11, 110 Electrode assembly 20, 200 battery case 210 Storage area 250 sealing part 250V gas exhaust 30, 300 electrode leads 400 lead film

Claims

1. a battery case including a sealing portion having a structure in which the electrode assembly is mounted in a housing portion and the outer periphery is sealed; and an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding toward an outside of the battery case through the sealing part; the sealing portion includes a gas exhaust portion; a portion of the sealing portion where the gas exhaust portion is not located is formed with a first sealing pattern; the gas exhaust portion is formed by a second sealing pattern, The first sealing pattern and the second sealing pattern are different from each other.

2. the first sealing pattern has repeated indentations and protrusions along the length of the sealing portion; The battery cell of claim 1 , wherein the second sealing pattern has repeated indentations and protrusions along a width direction of the sealing portion.

3. The battery cell of claim 2 , wherein the intervals between the recessed portions and the protruding portions of the first sealing pattern and the second sealing pattern are the same.

4. The battery cell of claim 2 , wherein a distance between the recessed portion and the protruding portion of the second sealing pattern is greater than a distance between the recessed portion and the protruding portion of the first sealing pattern.

5. The battery cell according to claim 1 , wherein the gas exhaust portion is located around the outer periphery of the sealing portion where the electrode lead is located.

6. The battery cell according to claim 5 , wherein the gas exhaust section is located in a portion of the outer periphery where the electrode leads are located, but where the electrode leads are not located.

7. The battery cell according to claim 1 , wherein the sealing strength of the gas exhaust portion is lower than the sealing strength of the sealing portion.

8. A battery module comprising the battery cell according to claim 1.

9. The battery module according to claim 8 , wherein the battery cells are stacked in a direction in which the gas discharge portion is adjacent to a bottom surface.

10. The battery module according to claim 9 , wherein the gas exhaust portion is formed in the sealing portion below the electrode lead in the battery cell.

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