KR20230007954A - Battery cell and battery module including the same - Google Patents

Abstract

According to one embodiment of the present invention, a battery cell comprises: a battery case having an electrode assembly mounted in a receiving portion, and a sealing portion having a structure in which an outer periphery thereof is sealed; an electrode lead electrically connected to an electrode tab of the electrode assembly and protruding outward of the battery case via the sealing portion; and a lead film located in a portion corresponding to the sealing portion, in at least one of an upper portion and a lower portion of the electrode lead, wherein a gas discharge inducing portion is inserted into the lead film, the battery case includes a cover portion extending from the sealing portion, and the cover portion may be located on the lead film and protruding outward of the battery case. According to one embodiment of the present invention, it is possible to improve insulation performance and gas discharge performance.

Description

Battery cell and battery module including the same {BATTERY CELL AND BATTERY MODULE INCLUDING THE SAME}

The present invention relates to a battery cell and a battery module including the same, and more particularly, to a battery cell having improved insulation performance and gas discharge performance, and a battery module including the same.

As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are of great interest as energy sources for power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles as well as mobile devices such as mobile phones, digital cameras, laptops, and wearable devices.

Depending on the shape of the battery case, these secondary batteries are classified into cylindrical batteries and prismatic batteries in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and pouch-type batteries in which the electrode assembly is embedded in a pouch-type case made of an aluminum laminate sheet. do. Here, the electrode assembly built into the battery case is a power generating device capable of charging and discharging, consisting of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode. It is classified into a jelly-roll type wound with a separator interposed and a stack type in which a plurality of positive and negative electrodes are sequentially stacked in a state in which a separator is interposed.

Among them, in particular, the pouch-type battery having a structure in which a stacked or stacked/folding type electrode assembly is embedded in a pouch-type battery case of an aluminum laminate sheet is gradually being used due to low manufacturing cost, small weight, and easy deformation shape. It is increasing.

1 is a top view of a conventional battery cell. FIG. 2 is a cross-sectional view taken along the a-a' axis in FIG. 1 .

1 and 2, the conventional battery cell 10 is a battery case including an electrode assembly 11 mounted in a housing 21 and a sealing unit 25 having a sealed outer periphery ( 20) included. In addition, the battery cell 10 is electrically connected to the electrode tab 15 included in the electrode assembly 11, and the electrode lead protrudes outward of the battery case 20 via the sealing portion 25 ( 30), and a lead film 40 is positioned between the upper and lower portions of the electrode lead 30 and the sealing portion 25.

However, as the energy density of the battery cell increases recently, there is a problem in that the amount of gas generated inside the battery cell also increases. In the case of the conventional battery cell 10, it does not include a part through which gas generated inside the battery cell can be discharged, and thus a venting phenomenon in which the battery case 20 bursts due to gas generation during long-term storage may occur. . In addition, moisture may permeate into the battery cell damaged by the venting phenomenon, causing a side reaction, resulting in deterioration in battery performance and generation of additional gas. Accordingly, there is a growing need to develop a battery cell with improved external discharge of gas generated inside the battery cell.

An object to be solved by the present invention is to provide a battery cell having improved insulation performance and gas discharge performance, and a battery module including the same.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and problems not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings. .

A battery cell according to an embodiment of the present invention includes a battery case including a sealing portion having a structure in which an electrode assembly is mounted in an accommodating portion and the outer periphery is sealed; an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing part; and a lead film located at a portion corresponding to the sealing portion in at least one of the upper and lower portions of the electrode lead, a gas discharge guide portion being inserted into the lead film, and the battery case extending from the sealing portion. and a cover portion that is positioned on the lead film and may protrude outward from the battery case.

The cover part may be located on the gas discharge guide part.

Based on a direction perpendicular to the protruding direction of the electrode lead, a length of the cover part may be equal to or greater than a length of the gas discharge guide part.

Based on a direction perpendicular to the protruding direction of the electrode lead, a length of the cover part may be equal to or smaller than a length of the lead film.

The gas discharge guide part may be located at a portion corresponding to the center of the cover part.

Based on the protruding direction of the electrode lead, an end of the cover part may be outside an end of the lead film.

Based on the protruding direction of the electrode lead, an end of the electrode lead may be outside an end of the cover part.

The cover part may be bent in a direction away from the lead film based on the sealing part.

The gas discharge guide portion may extend along a protruding direction of the electrode lead, and an end portion of the gas discharge guide portion adjacent to an outer side of the battery case may be wrapped with the lead film.

An end of the gas discharge guide part adjacent to the inside of the battery case may be exposed inside the battery case.

A gas discharge path may be formed at an interface between the gas discharge guide part and the lead film.

An adhesive force between the gas discharge guide part and the lead film may be smaller than an adhesive force between the lead film and the electrode lead or between the lead film and the sealing part.

The gas discharge guide part may be a film layer made of at least one of polyimide and polyethylene terephthalate.

The gas discharge guide part may be a coating layer made of liquid resin.

The gas discharge inducer is a getter material including at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO ₂ ), barium oxide (BaO), barium (Ba), and calcium (Ca). may further include.

The gas discharge guide part may be positioned on the electrode lead, and an adhesive layer may be formed between the gas discharge guide part and the electrode lead.

An adhesive force between the gas discharge induction part and the lead film may be smaller than an adhesive force between the adhesive layer and the gas discharge induction part and an adhesive force between the adhesive layer and the electrode lead.

The adhesive layer may be made of an adhesive tape or an adhesive binder.

Gas permeability of the lead film may be 20 to 60 barrer at 60°C.

Moisture permeation of the lead film may be 0.02 g to 0.2 g for 10 years at 25° C. and 50% RH.

Gas permeability of the gas discharge guide part may be 40 barrer or more at 60°C.

A battery module according to another embodiment of the present invention includes the battery cell described above.

According to embodiments, the present invention provides a battery cell and a battery module including the battery case extending from the sealing portion and including a cover portion positioned on a lead film, so that insulation performance and gas discharge performance are improved. can

Specifically, according to one aspect of the present invention, a gas discharge path can be formed at the interface between the gas discharge induction unit and the lead film, so that the gas in the battery cell can be effectively discharged to the outside while the manufacturing process is relatively easy. .

According to another aspect of the present invention, the cover part may be located outside the end of the lead film, so that insulation performance of the end surface of the cover part may be improved. Even when a crack is generated in the gas discharge path due to an increase in the internal pressure of the battery case, the end surface of the cover part is located outside the gas discharge path, so it may not come into contact with the electrolyte leaking out of the gas discharge path. Insulation performance can also be improved.

According to another aspect of the present invention, the gas discharge performance of the gas discharge guide portion and the durability and airtightness of the lead film may be controlled by adjusting the shape of the gas discharge guide portion. In addition, by changing the shape of the gas discharge guide unit as needed, the manufacturing process can be simplified and the cost can be reduced.

According to another aspect of the present invention, by setting the gas permeability and moisture penetration of the lead film within a predetermined range, it may be more effective to prevent moisture penetration from the outside while discharging gas generated inside the battery cell.

The effect of the present invention is not limited to the above-mentioned effects, and effects not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

1 is a top view of a conventional battery cell.
FIG. 2 is a cross-sectional view taken along the aa′ axis in FIG. 1 .
3 is a top view of a battery cell according to an embodiment of the present invention.
FIG. 4 is an enlarged view of the dotted-dashed line region of FIG. 3 .
5 is a cross-sectional view taken along the AA′ axis of FIG. 3 .
6 shows various shapes of the gas discharge guide part.
FIG. 7 is an enlarged view of the two-dot chain line area of FIG. 5 .
FIG. 8 is a view showing a gas discharge path formed between the interface of the lead film of FIG. 7 and the gas discharge induction unit.
FIG. 9 is a view illustrating leakage of electrolyte due to cracks generated in some of the gas discharge paths of FIG. 8 .
10 is a cross-sectional view taken along the AA′ axis of FIG. 3 in a battery cell according to another embodiment of the present invention.
FIG. 11 is an enlarged view of the dotted-dot chain line area of FIG. 10 .
FIG. 12 is a view showing a gas discharge path formed between the interface of the lead film of FIG. 11 and the gas discharge induction unit.
FIG. 13 is a view illustrating leakage of electrolyte due to cracks generated in some of the gas discharge paths of FIG. 12 .
14 is a cross-sectional view taken along the a-a′ axis of FIG. 1 according to a comparative example.
FIG. 15 is a view illustrating leakage of electrolyte solution due to cracks generated in a part of a gas discharge path in FIG. 14 by enlarging the dotted-dashed line area of FIG.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. This invention may be embodied in many different forms and is not limited to the embodiments set forth herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to the shown bar. In the drawings, the thickness is shown enlarged to clearly express the various layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

In addition, throughout the specification, when a part "includes" a certain component, it means that it may further include other components, not excluding other components unless otherwise stated.

In addition, throughout the specification, when it is referred to as "planar image", it means when the target part is viewed from above, and when it is referred to as "cross-sectional image", it means when a cross section of the target part cut vertically is viewed from the side.

Hereinafter, a battery cell according to an embodiment of the present invention will be described. However, this will be described based on one end of the battery cell, but is not necessarily limited thereto, and may be described with the same or similar content even in the case of the opposite end of the battery cell.

3 is a top view of a battery cell according to an embodiment of the present invention.

The battery cell 100 according to an embodiment of the present invention is a battery case 200 including a sealing part 250 having a structure in which the electrode assembly 110 is mounted in the housing part 210 and the outer periphery is sealed. ); an electrode lead 300 electrically connected to the electrode tab 150 included in the electrode assembly 110 and protruding outward of the battery case 200 via the sealing portion 250; and a lead film 400 positioned at a portion corresponding to the sealing portion 250 in at least one of the upper and lower portions of the electrode lead 300 . For example, the battery cell 100 has a long side in the direction along the X-axis, a short side in the direction along the Y-axis, and a smaller thickness than the length of the X-axis or Y-axis in the Z-axis direction, so that it can be a substantially rectangular plate-shaped cell there is. An electrode lead 300 may be formed on a short side of the battery cell 100 . This battery cell 100 is an efficient structure for increasing energy density by stacking several battery cells 100 face-to-face by integrating them in the Z-axis direction.

The electrode assembly 110 may have a structure of a jelly-roll type (winding type), a stack type (lamination type), or a combination type (stack/folding type). More specifically, the electrode assembly 110 may include an anode, a cathode, and a separator disposed between them.

The electrode lead 300 is electrically connected to the electrode tab 150 included in the electrode assembly 110 and protrudes outward from the battery case 200 via the sealing portion 250 . In addition, the 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 . Accordingly, the lead film 400 prevents a short circuit from occurring in the electrode lead 300 during thermal fusion or press fusion together with the sealing portion 250, and sealability between the sealing portion 250 and the electrode lead 300. can improve

Referring to FIG. 3 , the lead film 400 may have a wider width than the electrode lead 300 . Here, 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 in a direction (Y-axis direction) perpendicular to the protrusion direction (X-axis 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 in a direction orthogonal to the protrusion direction of the electrode lead 300 .

The lead film 400 may have a length greater than the length of the sealing portion 250 based on the protruding direction of the electrode lead 300 and a length smaller than the length of the electrode lead 300 . Here, 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 in the protruding direction of the electrode lead 300 . The length of the sealing part 250 means the maximum value of the distance between one end and the other end of the sealing part 250 in the protruding direction of the electrode lead 300 . The length of the electrode lead 300 means the maximum value of the distance between one end and the other end of the electrode lead 300 in the protruding direction of the electrode lead 300 . Accordingly, the lead film 400 may prevent the side surface of the electrode lead 300 from being exposed to the outside without interfering with the electrical connection of the electrode lead 300 .

The battery case 200 may be a laminate sheet including a resin layer and a metal layer. More specifically, the battery case 200 is made of a laminate sheet and may be composed of an outer resin layer constituting the outermost shell, a barrier metal layer preventing penetration of materials, and an inner resin layer for sealing. For example, the barrier metal layer may be made of an aluminum material.

Here, the battery case 200 may be manufactured by cutting the laminate sheet according to a predetermined shape, and the edge of the battery case 200 has cross sections of the outer resin layer, the barrier metal layer, and the inner resin layer. may be exposed to the outside world. Here, methods such as laser cutting, knife cutting, and mold punching may be applied to the cutting method, but are not limited thereto, and a cutting method generally applied when cutting a laminate sheet may also be included in this embodiment.

However, in the battery case 200, when the barrier metal layer exposed at the edge of the battery case 200 comes into contact with an external material or an electrolyte, an electric circuit may be formed, leading to a fire. Accordingly, in the present embodiment, it is necessary to secure insulation for the barrier metal layer exposed at the edge of the battery case 200 .

FIG. 4 is an enlarged view of the dotted-dashed line region of FIG. 3 . 5 is a cross-sectional view taken along the A-A' axis of FIG. 3;

Referring to FIGS. 4 and 5 , in this embodiment, the gas discharge guide part 450 is inserted into the lead film 400, and the battery case 200 has a cover part 270 extending from the sealing part 250. ) may be included.

Here, the sealing part 250 and the cover part 270 may be integrated with each other. More specifically, as heat fusion or press fusion is performed between the housing unit 210 and the cover unit 270 in the battery case 200, the sealing unit 250 is formed between the housing unit 210 and the cover unit 270. may have been formed.

In addition, the cover part 270 extends from the sealing part 250 and may protrude outward from the battery case 200 . More specifically, the cover part 270 may extend from the sealing part 250 positioned on the lead film 400 . That is, the cover part 270 may be positioned on the lead film 400 . Here, based on the sealing part 250 , the cover part 270 may extend in the same direction as the direction in which the lead film 400 protrudes outward from the battery case 200 .

Also, the cover part 270 may be located on the gas discharge guide part 450 . More specifically, the cover part 270 may be positioned on the gas discharge guide part 450 with the lead film 400 interposed therebetween. In other words, the cover part 270 may be located in a part corresponding to the part where the gas discharge guide part 450 is located in the lead film 400 . That is, the cover part 270 may cover a portion of the lead film 400 where the gas discharge guide part 450 is located. When cutting the battery case 200, the cover part 270 is cut so that it is longer than the sealing part 250 in the X-axis direction, thereby covering the portion where the gas discharge induction part 450 is located. can provide

For example, the gas discharge induction unit 450 may be located at a portion corresponding to the center of the cover unit 270 . In other words, the center line of the gas discharge guide part 450 and the center line of the cover part 270 may coincide with each other.

According to the above configuration, in the present embodiment, the cover part 270 may be positioned on the gas discharge guide part 450 of the lead film 400, and is formed by the lead film 400 and the gas discharge guide part 450. A portion of the gas discharge path exposed to the outside of the battery case 200 may be covered. In other words, the cut surface of the battery case 200 can cover the gas discharge path.

Referring to FIG. 4 , the length of the cover part 270 may be equal to or greater than the length of the gas discharge guide part 450 based on a direction perpendicular to the protruding direction of the electrode lead 300 . Here, the length of the cover part 270 means the maximum value of the distance between one end and the other end of the cover part 270 in a direction orthogonal to the protruding direction of the electrode lead 300 . The length of the gas discharge guide part 450 means the maximum value of the distance between one end and the other end of the gas discharge guide part 450 in a direction orthogonal to the protruding direction of the electrode lead 300 .

Accordingly, the cover part 270 may cover all parts of the gas discharge guide part 450 located outside the battery case 200 in the lead film 400 . That is, the entirety of the gas discharge path formed by the lead film 400 and the gas discharge induction part 450 exposed to the outside of the battery case 200 can be effectively covered.

For example, based on a direction perpendicular to the protruding direction of the electrode lead 300 , the length of the cover part 270 may be equal to or smaller than the length of the lead film 400 . Here, 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 in a direction perpendicular to the protruding direction of the electrode lead 300 . That is, the cover part 270 may cover part or all of the part where the lead film 400 is located.

According to the above configuration, in this embodiment, the cover part 270 may have a size similar to that of the lead film 400, effectively covering a portion where the gas discharge induction part 450 is located, and Space efficiency can be increased.

However, the size of the cover part 270 is not limited thereto, and as described above, any size that can cover a portion where the gas discharge induction part 450 is located may be included in the present embodiment.

Referring to FIGS. 4 and 5 , the end of the cover part 270 may be outside the end of the lead film 400 based on the protruding direction of the electrode lead 300 . In other words, an end of the cover part 270 may extend from the sealing part 250 and may extend outward from the end of the lead film 400 .

More specifically, the cover part 270 may be bent in a direction (Z-axis direction) away from the lead film 400 based on the sealing part 250 . Here, the angle at which the cover part 270 is bent with respect to the sealing part 250 may be an angle generated as the sealing part 250 is fused. However, the angle at which the cover part 270 is bent with respect to the sealing part 250 may be adjusted smaller or larger than the angle generated as the sealing part 250 is fused, as needed.

Accordingly, in the present embodiment, the cover part 270 may be located outside the end of the lead film 400, so that the insulation performance of the cross section of the end of the cover part 270 may be improved. That is, even when a crack is generated in the gas discharge path as the internal pressure of the battery case 200 increases, the end surface of the cover part 270 is located outside the gas discharge path, so that the gas discharge path It may not be in contact with the electrolyte leaking to the outside, and thus the insulation performance may also be improved. In other words, by cutting the battery case 200 in the gas discharge path part long, the cut surface of the battery case 200 sufficiently covers the gas discharge path, so that even if the electrolyte leaks, the exposed surface of the battery case 200 Since the barrier metal layer does not come into contact with the leaked electrolyte, insulation performance can be maintained without forming an electrical circuit.

Also, based on the protruding direction of the electrode lead 300 , the end of the electrode lead 300 may be outside the end of the cover part 270 . In other words, the end of the cover part 270 extends from the sealing part 250 and may extend shorter than the end of the electrode lead 300 .

Accordingly, in the present embodiment, the end of the electrode lead 300 is outside the end of the cover part 270, so that the cover part 270 improves insulation performance and prevents contact between the electrode lead 300 and other components. It may not disturb the electrical connection.

Referring to FIGS. 4 and 5 , the gas discharge guide part 450 may extend along the protruding direction of the electrode lead 300 . More specifically, in the gas discharge induction unit 450 , an end of the gas discharge induction unit 450 adjacent to the outside of the battery case 200 may be wrapped with a lead film 400 . In other words, the end of the gas discharge guide part 450 adjacent to the outside of the battery case 200 may not be exposed to the outside of the battery case 200 .

In addition, an end of the gas discharge guide part 450 adjacent to the inside of the battery case 200 may be exposed inside the battery case 200 . In other words, the end of the gas discharge guide part 450 adjacent to the inside of the battery case 200 is located on the same vertical line as the end of the lead film 400, or is located on the same vertical line as the end of the lead film 400, the battery case 200 It can be located inside.

Accordingly, in the lead film 400, one end of the gas discharge guide part 450 adjacent to the outside of the battery case 200 is not exposed to the outside of the battery case 200, so that the lead film 400 and the sealing portion The sealing force of the battery case 200 by 250 can be improved. In addition, in the lead film 400, the end of the gas discharge induction unit 450 adjacent to the inside of the battery case 200 is exposed to the inside of the battery case 200, and the gas discharge formed by the gas discharge induction unit 450 is exposed. The path allows the gas generated in the battery cell 100 to be easily introduced and effectively discharged to the outside.

Referring further to FIG. 5 , the lead film 400 on the upper surface of the gas discharge guide part 450 may have a thickness (height in the H and Z-axis directions) of 100 μm to 300 μm, or 100 μm to 200 μm. . When the thickness (H) of the lead film 400 satisfies the aforementioned range, gas inside the battery case 200 may be more easily discharged to the outside.

Referring to FIG. 5 , based on the protruding direction of the electrode lead 300, the width W of the lead film 400 surrounding the front surface of the gas discharge guide part 450 is 2 mm or more, or 2 mm to 3 mm. can be When the width (W) of the lead film 400 satisfies the aforementioned range, the lead film 400 can be prevented from tearing as much as possible while the gas generated inside the battery case 200 is discharged to the outside.

In addition, the thickness (D) of the gas discharge guide portion 450 may be 50 ㎛ to 150 ㎛. When the thickness of the gas discharge guide part 450 satisfies the aforementioned range, gas inside the battery case 200 may be more easily discharged to the outside. 6 shows various shapes of the gas discharge guide part. The gas discharge induction unit 450 may be formed in a predetermined pattern to discharge gas inside the battery case 200 .

For example, the gas discharge induction unit 450 may have a rectangular shape extending along the protruding direction of the electrode lead 300 as shown in FIG. 4 . However, it is not limited thereto, and the gas discharge inducing unit 450 may have various shapes such as a circular shape as shown in FIG. 6 (a), an elliptical shape as shown in FIG.

As another example, the gas discharge induction unit 450 is formed in the first gas discharge induction unit 450a extending along the protrusion direction of the electrode lead 300 and in the protrusion direction of the electrode lead 300 as shown in (c) of FIG. 6 . A second gas discharge guide part 450b extending in a vertical direction may be included. In particular, the first gas discharge guide part 450a and the second gas discharge guide part 450b may be connected to each other. Here, the second gas discharge inducing part 450b is located inside the lead film 400 to the outside of the sealing part 250 based on the sealing part 250 as shown in (c) of FIG. As shown in (d), it may be located on the outside of the lead film 400 to the inside of the sealing part 250 based on the sealing part 250 . Alternatively, the second gas discharge inducing part 450b may be located both outside the lead film 400 and inside the lead film 400 based on the sealing part 250 as shown in (e) of FIG. 6 . However, the shape of the gas discharge induction unit 450 is not limited to the above description, and may be inserted into the lead film 400 in an appropriate shape. Accordingly, the gas discharge performance of the gas discharge induction unit 450 and durability and airtightness of the lead film 400 may be controlled by adjusting the shape of the gas discharge induction unit 450 inserted into the lead film 400 . In addition, by changing the shape of the gas discharge induction unit 450 as needed, it is possible to simplify the manufacturing process and reduce costs.

For example, only one gas discharge inducing unit 450 may be included in the lead film 400 as shown in FIG. 4 . As another example, a plurality of gas discharge induction units 450 may be inserted into the lead film 400 and may be spaced apart from each other.

Accordingly, the gas discharge performance of the gas discharge induction unit 450 and the durability and airtightness of the lead film 400 may be controlled by adjusting the number of gas discharge induction units 450 inserted into the lead film 400 . In addition, by minimizing the number of gas discharge induction units 450 as needed, the manufacturing process can be simplified and costs can be reduced.

FIG. 7 is an enlarged view of the two-dot chain line area of FIG. 5 . FIG. 8 is a view showing a gas discharge path formed between the interface of the lead film of FIG. 7 and the gas discharge induction unit. FIG. 9 is a view illustrating leakage of electrolyte due to cracks generated in some of the gas discharge paths of FIG. 8 .

Referring to FIGS. 7 and 8 , in this embodiment, a gas discharge path may be formed at an interface between the gas discharge induction unit 450 and the lead film 400 . More specifically, as shown in FIGS. 7 and 8 , in the gas discharge path, at least a part of the interface between the gas discharge guide part 450 and the lead film 400 is formed by the pressure of the gas generated from the battery case 200. It may mean spaces spaced apart from each other. In FIG. 8 , a gas movement path is indicated by a dotted line arrow. That is, as shown in the direction of the dotted line arrow in FIG. 8 , the gas discharge path means a path through which gas is introduced into and discharged from the space spaced apart from each other at the interface between the gas discharge guide part 450 and the lead film 400 . can

Here, the adhesive force between the gas discharge guide part 450 and the lead film 400 may be smaller than the adhesive force between the lead film 400 and the electrode lead 300 or the adhesive force between the lead film 400 and the sealing part 250. there is. More specifically, when the pressure inside the battery case 200 increases due to the gas generated in the battery cell 100, the adhesive force of the interface between the gas discharge guide part 450 and the lead film 400 is increased by the lead film ( 400) and other components, as shown in FIG. 8, at least a part of the interface between the gas discharge guide part 450 and the lead film 400 is formed by the pressure of the gas generated from the battery cell 100. may be separated from each other.

That is, in the present embodiment, due to the relatively low adhesive force between the gas discharge induction unit 450 and the lead film 400, the gas discharge induction unit 450 and the lead film 400 are separated while the gas discharge induction unit 450 and the lead film 400 are separated. The gas inside the battery cell 100 may flow into the gas discharge passage formed at the interface between the lead films 400, and the gas moves along the gas discharge passage and is finally discharged through the lead film 400. It can be. Gas introduced into the gas discharge passage may be discharged toward the outside according to a pressure difference with the outside.

However, in the gas discharge path, as shown in FIG. 8 , the interface between the upper surface of the gas discharge guide part 450 and the lead film 400 and the interface between the lower surface of the gas discharge guide part 450 and the lead film 400 are all spaced apart. It may also include a case where the interface between the upper surface of the gas discharge induction unit 450 and the lead film 400 or the interface between the lower surface of the gas discharge induction unit 450 and the lead film 400 is spaced apart from each other. there is.

For example, the gas discharge guide part 450 may be a film layer made of at least one of polyimide (PI) and polyethylene terephthalate (PET). As another example, the gas discharge guide part 450 may be a coating layer made of liquid resin. However, the shape of the gas discharge induction unit 450 or the material constituting the same is not limited thereto, and the adhesive strength of the interface between the gas discharge induction unit 450 and the lead film 400 is not limited to that between the lead film 400 and other components. Any shape or material capable of lowering the adhesive force may be included in this embodiment.

Accordingly, the battery cell according to the present embodiment discharges gas at the interface between the gas discharge induction unit 450 and the lead film 400 through a relatively low adhesive force between the gas discharge induction unit 450 and the lead film 400. Since a path can be formed, the gas in the battery cell 100 can be effectively discharged to the outside while the manufacturing process is relatively easy.

Referring again to FIGS. 4 and 5 , based on the protruding direction of the electrode lead 300 , one end of the gas discharge inducing part 450 may be located inside the inner surface of the sealing part 250 . In this specification, the inner surface of the sealing part 250 means the end of the sealing part 250 adjacent to the inside of the battery case 200, and is located inside the inner surface of the sealing part 250 means that the seal It means that it is located in the inner direction of the battery case 200 than the inner surface of the part 250. When one end of the gas discharge induction part 450 is located inside the sealing part 250, it is not interfered with by the sealing part 250, and it is easier for gas to flow into the gas discharge induction part 450. there is.

In addition, based on the protruding direction of the electrode lead 300 , the other end of the gas discharge inducing part 450 may be positioned outside the outer surface of the sealing part 250 . In this specification, the outer surface of the sealing part 250 means the end of the sealing part 250 adjacent to the outside of the battery case 200, and is located outside the outer surface of the sealing part 250 means that the seal It means that it is located in the outer direction of the battery case 200 than the outer surface of the portion 250. For example, a gap P is provided between the outer surface of the sealing part 250 and the other end of the gas discharge inducing part 450 . In this way, when the other end of the gas discharge induction unit 450 is positioned outside the outer surface of the sealing unit 250, the gas flowing into the gas discharge induction unit 450 may be more easily discharged to the outside. For example, since the other end of the gas discharge induction unit 450 is not interfered with by the sealing unit 250, the gas flowing into the gas discharge induction unit 450 may be more easily discharged to the outside.

Accordingly, the gas generated inside the battery cell 100 is discharged toward the gas discharge induction unit 450, and the gas introduced into the gas discharge induction unit 450 is easily discharged toward the outside as shown in FIG. can In addition, external discharge of gas generated inside the battery cell 100 may also be increased. In this way, gas generated inside the battery case 200 can be easily discharged to the outside of the gas discharge induction unit 450 while being easily introduced into the gas discharge induction unit 450 .

In addition, as shown in FIG. 8 , the gas flowing into the gas discharge induction unit 450 may be particularly easily discharged along the Z-axis direction through the lead film 400 on the gas discharge induction unit 450 . For example, when the other end of the gas discharge induction unit 450 is positioned outside the outer surface of the sealing unit 250, the gas flowing into the gas discharge induction unit 450 flows between the other end of the gas discharge induction unit 450 and the sealing unit. The portion of the lead film 400 between the outer surfaces of the 250 may be discharged along the Z-axis direction. As mentioned above, the thickness H of the lead film 400 on the upper surface of the gas discharge induction unit 450 may be 100 μm to 300 μm, based on the protruding direction of the electrode lead 300, the gas discharge induction unit The width W of the lead film 400 surrounding the entire surface of the lead film 450 may be 2 mm or more, or 2 mm to 3 mm. As described above, when the other end of the gas discharge inducing part 450 is located outside the outer surface of the sealing part 250, the gas is discharged through a relatively thin part of the lead film 400, which is placed in the Z-axis direction. It can be. Therefore, gas discharge is easier. In addition, when the gas discharge occurs, if the gas discharge path is completely blocked by the sealing portion 250, the gas discharge is not smooth. There is an effect of facilitating gas discharge by leaving a gap P therebetween.

Referring to FIG. 9 , in the present embodiment, in the gas discharge path formed at the interface between the gas discharge induction unit 450 and the lead film 400, a crack may be formed in a portion of the lead film 400 after a certain period of time has elapsed. can More specifically, when gas inside the battery cell 100 continuously flows in and out of the gas discharge path, an end portion of the lead film 400 adjacent to the outside of the battery case 200 may become structurally weak. . Even if the width (W) of the lead film 400 surrounding the front surface of the gas discharge induction unit 450 is 2 mm or more to prevent the lead film 400 from being torn, as the use of the battery cell 100 continues, the lead film Cracks may form in it. In this case, the electrolyte solution 50 inside the battery cell 100 may leak to the outside through the crack.

Here, referring to FIGS. 7 to 9 , in the battery cell 100 according to this embodiment, the cover part 270 may be located outside the end of the lead film 400, and the cover part 270 The end may be located outside the end of the gas discharge path. Accordingly, in the present embodiment, even if a crack is generated and the electrolyte 50 leaks, the electrolyte leaking out of the gas discharge path may not come into contact with the end face of the cover part 270 .

As shown in FIG. 9, even if the electrolyte 50 leaks through the crack, the leaked electrolyte is located on the inner resin layer side of the cover part 270 and is difficult to reach the barrier metal layer exposed on the end surface of the end of the cover part 270 . That is, the barrier metal layer exposed on the end surface of the end of the cover part 270 may not come into contact with the electrolyte leaking out of the gas discharge path, so that an electric circuit between the barrier metal layer and the electrolyte is formed. can be prevented, and thus insulation performance and safety can also be improved.

In addition, the gas discharge inducing unit 450 may further include a material having a function of absorbing or adsorbing moisture introduced from the outside or hydrofluoric acid generated from the inside. More specifically, the gas discharge guide 450 may further include a getter material. Here, the getter material may refer to a material capable of vacuum exhausting by using an action in which gas is adsorbed by a chemically activated metal film. For example, 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). . As another example, the getter material may have a structure of a metal organic framework (MOF). However, the getter material is not limited thereto, and may include all types of materials generally classified as getter materials.

Accordingly, in this embodiment, the gas discharge induction unit 450 further includes a material capable of absorbing or adsorbing moisture or hydrofluoric acid, so that the gas discharge induction unit 450 moves from the outside of the battery cell 100 to the inside of the battery cell 100. It is possible to more easily discharge the gas generated inside the battery cell 100 to the outside while being able to more minimize the infiltration of moisture or hydrofluoric acid.

In one embodiment of the present invention, gas permeability of the gas discharge guide part 450 may be 40 barrer or more at 60°C. For example, the carbon dioxide permeability of the gas discharge guide part 450 may satisfy the aforementioned range.

For example, the gas discharge induction unit 450 may include at least one of polyolefin-based, fluorine-based, and porous ceramic-based materials that satisfy the aforementioned gas permeability value. The polyolefin-based material may include at least one material selected from the group consisting of polypropylene, polyethylene, and polyvinyldifluoride (PVDF). The fluorine-based material may include at least one material selected from the group consisting of polytetrafluoroethylene and polyvinylidene fluoride.

In one embodiment of the present invention, the gas permeability of the lead film 400 may be 20 to 60 barrer or 30 to 40 barrer at 60°C. For example, the carbon dioxide permeability of the lead film 400 may satisfy the aforementioned range. Also, based on the thickness (H) of the lead film 400 of 200 μm, gas permeability may satisfy the aforementioned range at 60° C. When the gas permeability of the lead film 400 satisfies the aforementioned range, gas generated inside the battery cell may be more effectively discharged.

In this specification, gas permeability can be measured according to ASTM F2476-20.

In one embodiment of the present invention, the moisture permeation amount of the lead film 400 may be 0.02 g to 0.2 g, or 0.02 g to 0.04 g, or 0.06 g or 0.15 g at 25° C. and 50% RH for 10 years. When the moisture permeation amount of the lead film 400 satisfies the above-described range, it may be more effective to prevent moisture from permeating the lead film 400 .

In one embodiment of the present invention, the lead film 400 may have a gas permeability of 20 to 60 barrer at 60 °C and a water permeability of 0.02 g to 0.2 g at 25 °C and 50% RH for 10 years. When the gas permeability and moisture permeability of the lead film 400 satisfy the aforementioned ranges, it may be more effective to prevent moisture penetration from the outside while discharging gas generated inside the battery cell 100 .

The moisture permeation amount of the lead film 400 may be measured by adopting the ASTM F 1249 method. At this time, it can be measured using equipment officially certified by MCOON.

In one embodiment of the present invention, the lead film 400 may be made of an adhesive composition made of at least one of a polyolefin-based material, epoxy, and polyvinyl chloride (PVC). The polyolefin-based material may be polyethylene (PE) or polypropylene (PP). For example, the lead film 400 may be made of polyethylene, polypropylene, or the like that satisfies the aforementioned gas permeability and/or moisture permeability values.

In addition, since the lead film 400 is made of the above-described material, airtightness of the battery cell 100 can be maintained, and leakage of the internal electrolyte solution can also be prevented.

Hereinafter, a battery cell according to another embodiment of the present invention will be described. However, the battery cell according to this embodiment may be described in the same way as the battery cell 100 described above, and the gas discharge induction unit 450 will be described with a focus on the difference from the battery cell 100. .

10 is a cross-sectional view of a battery cell according to another embodiment of the present invention, taken along the A-A' axis of FIG.

Referring to FIGS. 4 and 10 , unlike FIG. 5 , in the present embodiment, the gas discharge induction unit 450' may be positioned on the electrode lead 300'. More specifically, a separate lead film 400' may not be positioned between the gas discharge inducing unit 450' and the electrode lead 300'. That is, the gas discharge guide 450' may be inserted into one side of the lead film 400' adjacent to the electrode lead 300' and positioned adjacent to the electrode lead 300'. In other words, the present embodiment may have a structure in which the lead film 400' covers the outer surface of the gas discharge induction unit 450' after the gas discharge induction unit 450' is attached or fixed on the electrode lead 300'.

Accordingly, as the gas discharge induction unit 450' is positioned adjacent to the electrode lead 300', the thickness of the lead film 400' surrounding the gas discharge induction unit 450' may also be relatively reduced, resulting in manufacturing cost. While this is reduced, there is an advantage in that the manufacturing process is easy.

In addition, an adhesive layer 470' may be formed between the gas discharge guide part 450' and the electrode lead 300'. Here, the adhesive layer 470' may extend along an interface between the gas discharge induction unit 450' and the electrode lead 300'. At this time, the adhesive layer 470' may be formed on all or part of the interface between the gas discharge induction unit 450' and the electrode lead 300'.

For example, the adhesive layer 470' may be formed of an adhesive tape or an adhesive binder. However, it is not limited thereto, and any material having adhesive performance capable of fixing the gas discharge guide 450' and the electrode lead 300' to each other may be applied without limitation.

Accordingly, the gas discharge guide 450' can be stably fixed to the electrode lead 300' by the adhesive layer 470'. That is, an adhesive layer 470' having a relatively high adhesive strength is formed between the gas discharge induction unit 450' and the electrode lead 300', so that peeling due to an increase in internal pressure of the battery cell 100 can be prevented. , The sealing strength of the battery cell 100 can also be further improved.

FIG. 11 is an enlarged view of the dotted-dot chain line area of FIG. 10 . FIG. 12 is a view showing a gas discharge path formed between the interface of the lead film of FIG. 11 and the gas discharge induction unit. FIG. 13 is a view illustrating leakage of electrolyte due to cracks generated in some of the gas discharge paths of FIG. 12 .

Referring to FIGS. 11 to 13 , similar to FIGS. 7 to 9 , a gas discharge path may be formed at an interface between the gas discharge induction unit 450' and the lead film 400'. However, this embodiment is different from FIGS. 7 to 9. The gas discharge induction unit 450' is located adjacent to the electrode lead 300', and the adhesive layer 470' is formed between the gas discharge induction unit 450' and the electrode lead 300', so that the gas discharge induction unit 450 ') and the electrode lead 300' may not form a gas discharge path. In FIG. 12 , a gas movement path is indicated by a dotted line arrow.

More specifically, in this embodiment, the adhesive force between the gas discharge induction part 450' and the lead film 400' is the adhesive force between the adhesive layer 470' and the gas discharge induction part 450' and/or the adhesive layer 470'. ) and the electrode lead 300'.

More specifically, in the present embodiment, when the pressure inside the battery cell 100 increases, the adhesive strength of the interface between the gas discharge induction unit 450' and the lead film 400' is different from that of the lead film 400'. As shown in FIG. 12 , at least some of the interfaces between the gas discharge guide part 450' and the lead film 400' may be spaced apart from each other due to internal pressure of the battery cell 100 because the adhesive force between elements is relatively smaller than that of the elements.

In addition, in this embodiment, the adhesive strength of the interface between the gas discharge induction unit 450' and the lead film 400' is the adhesive strength between the gas discharge induction unit 450' and/or the adhesive layer 470' and the electrode lead ( 300'), it is possible to prevent the interface between the gas discharge guide part 450' and the electrode lead 400' from being peeled off when the internal pressure of the battery cell 100 increases.

That is, in the present embodiment, only the interface between the gas discharge guide 450' and the lead film 400' can be separated to form a gas discharge path, and the battery cell ( 100) can increase the sealing strength. In addition, according to the high sealing strength, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can be higher, and safety can be further improved.

In addition, in this embodiment, the gas discharge path can be formed only at the interface between the gas discharge induction unit 450' and the lead film 400', and even if the gas discharge path is cracked as shown in FIG. 13, The electrolyte solution 50 inside the battery cell 100 may be induced to be discharged in the direction where the cover part 270 is located. That is, insulation performance and safety can be further improved accordingly.

Hereinafter, the battery cell according to the comparative example of the present invention will be mainly described. In the case of a comparative example, description will be made in comparison with the embodiment according to FIGS. 3 to 9 , but the embodiment according to FIGS. 10 to 13 can be compared and described in the same way.

14 is a cross-sectional view taken along the a-a′ axis of FIG. 1 according to a comparative example. FIG. 15 is a view illustrating leakage of electrolyte solution due to cracks generated in a part of a gas discharge path in FIG. 14 by enlarging the dotted-dashed line area of FIG.

14 and 15, it relates to a battery cell 10 according to a comparative example, except for a configuration in which a gas discharge induction unit 45 is included in the comparative example, as in the present embodiment, FIG. 1 and FIG. It can be described in the same way as the battery cell 10 of 2. Hereinafter, the gas discharge induction unit 45 will be mainly described.

Referring to FIG. 14, the battery cell 10 according to the comparative example has a sealing portion 25 formed on the lead film 40 where the gas discharge induction portion 45 is located, and unlike FIGS. No separate component extending from the end of section 25 is included. That is, the end face of the sealing portion 25 may be exposed to the outside, and in particular, the end face of the sealing portion 25 may be located on a gas discharge path formed by the lead film 40 and the gas discharge guide portion 45. can

Referring to FIG. 15 , even in the case of the battery cell 10 according to the comparative example, as shown in FIG. 9 , cracks may occur in some of the lead films 40 as time passes, and the battery cell may be formed through the cracks. (10) The electrolyte solution 50 inside may leak to the outside.

However, in the case of the battery cell 10 according to the comparative example, the cross section of the sealing portion 25 is located on a gas discharge path formed by the lead film 40 and the gas discharge inducing portion 45, so that the sealing portion 25 ) and the electrolyte leaking out of the gas discharge path may contact each other as shown in FIG. 15 . That is, the barrier metal layer exposed on the end surface of the sealing portion 25 can come into contact with the electrolyte leaking out of the gas discharge path, so that an electric circuit is formed between the barrier metal layer and the electrolyte, resulting in a fire. may occur, and safety may be greatly deteriorated.

3 to 9, in the battery cell 100 according to this embodiment, the cover part 270 extends from the sealing part 250 located on the gas discharge induction part 450, An end of the cover part 270 may be located outside the end of the gas discharge path. That is, unlike the comparative example, in this embodiment, even if a crack occurs in a portion of the lead film 400, the electrolyte leaking from the crack may not come into contact with the end of the cover part 270. Formation of an electric circuit between the end and the electrolyte may be prevented, and thus insulation performance and safety may also be improved.

A battery module according to another embodiment of the present invention includes the battery cell described above. 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.

The battery module described above and the battery pack including the battery module may be applied to various devices. Such devices may be applied to means of transportation such as electric bicycles, electric vehicles, hybrid vehicles, etc., but the present invention is not limited thereto and is applicable to various devices capable of using a battery module and a battery pack including the same, which is also applicable to the present invention. Belongs to the scope of the right of invention.

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 of those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It falls within the scope of the right of invention.

100: battery cell
110: electrode assembly
200: battery case
210: storage unit
250: sealing part
270: cover part
300: electrode lead
400: lead film
450: gas discharge induction unit

Claims (22)

A battery case including a sealing part having an outer periphery sealed in which the electrode assembly is mounted in the receiving part;
an electrode lead electrically connected to an electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing part; and
A lead film positioned at a portion corresponding to the sealing portion in at least one of the upper and lower portions of the electrode lead,
A gas discharge guide is inserted into the lead film,
The battery case includes a cover portion extending from the sealing portion,
The battery cell wherein the cover portion is located on the lead film and protrudes outward from the battery case. In paragraph 1,
The cover portion is a battery cell located on the gas discharge induction portion. In paragraph 2,
The gas discharge induction unit is a battery cell located in a portion corresponding to the center of the cover unit. In paragraph 2,
Based on a direction perpendicular to the protruding direction of the electrode lead, the length of the cover portion is equal to or greater than the length of the gas discharge induction portion battery cell. In paragraph 4,
Based on a direction perpendicular to the protruding direction of the electrode lead, the length of the cover portion is equal to or smaller than the length of the lead film. In paragraph 1,
A battery cell in which an end of the cover part is outside an end of the lead film based on a protruding direction of the electrode lead. In paragraph 6,
Based on the protruding direction of the electrode lead, the end of the electrode lead is outside the battery cell than the end of the cover portion. In paragraph 6,
The battery cell wherein the cover portion is bent in a direction away from the lead film based on the sealing portion. In paragraph 1,
The battery cell of claim 1 , wherein the gas discharge guide portion extends along a protruding direction of the electrode lead, and an end portion of the gas discharge guide portion adjacent to an outer side of the battery case is wrapped with the lead film. In paragraph 9,
An end portion of the gas discharge guide part adjacent to the inside of the battery case is exposed inside the battery case. In paragraph 1,
A battery cell in which a gas discharge path is formed at an interface between the gas discharge guide part and the lead film. In paragraph 11,
The adhesive force between the gas discharge guide part and the lead film is smaller than the adhesive force between the lead film and the electrode lead or the adhesive force between the lead film and the sealing part. In paragraph 12,
The battery cell wherein the gas discharge induction unit is a film layer made of at least one of polyimide and polyethylene terephthalate. In paragraph 12,
The battery cell wherein the gas discharge induction part is a coating layer made of liquid resin. In paragraph 12,
The gas discharge inducer is a getter material including at least one of calcium oxide (CaO), lithium chloride (LiCl), silica (SiO ₂ ), barium oxide (BaO), barium (Ba), and calcium (Ca). A battery cell further comprising a. In paragraph 1,
The battery cell wherein the gas discharge induction unit is located on the electrode lead, and an adhesive layer is formed between the gas discharge induction unit and the electrode lead. In clause 16,
The battery cell of claim 1 , wherein an adhesive force between the gas discharge induction unit and the lead film is smaller than at least one of an adhesive force between the adhesive layer and the gas discharge induction unit and an adhesive force between the adhesive layer and the electrode lead. In paragraph 17,
The adhesive layer is a battery cell made of an adhesive tape or an adhesive binder. In paragraph 1,
A battery cell in which the gas permeability of the lead film is 20 to 60 barrer at 60 ° C. In paragraph 1,
A battery cell having a water permeation amount of the lead film of 0.02 g to 0.2 g for 10 years at 25 ° C. and 50 % RH. In paragraph 1,
A battery cell in which the gas permeability of the gas discharge induction unit is 40 barrer or more at 60 ° C. A battery module comprising the battery cell according to claim 1.

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