KR102657917B1 - Battery cell and battery cell manufacturing device for manufacturing the same - Google Patents

Abstract

A battery cell according to an embodiment of the present invention includes a battery case including a sealing portion in which an electrode assembly is mounted in a receiving portion and the outer periphery is sealed; an electrode lead electrically connected to the electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing portion; and a lead film positioned at a portion corresponding to the sealing portion at at least one of an upper and lower portion of the electrode lead, wherein the lead film includes a first step protruding in a direction opposite to the direction toward the electrode lead. The sealing part includes a second step portion surrounding an outer surface of the first step portion, and a gas discharge guide portion is inserted into the first step portion.

Description

Battery cell and battery cell manufacturing device for manufacturing the same {BATTERY CELL AND BATTERY CELL MANUFACTURING DEVICE FOR MANUFACTURING THE SAME}

The present invention relates to a battery cell and a battery cell manufacturing device for manufacturing the same, and more specifically, to a battery cell with improved sealing strength and safety while improving the external emission of gas generated inside the battery cell, and a battery cell manufacturing device for manufacturing the same. It's about devices.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. In particular, secondary batteries are receiving much attention as an energy source for not only mobile devices such as mobile phones, digital cameras, laptops, and wearable devices, but also power devices such as electric bicycles, electric vehicles, and hybrid electric vehicles.

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 built into a cylindrical or square metal can, and pouch-type batteries in which the electrode assembly is built in a pouch-shaped case of aluminum laminate sheet. do. Here, the electrode assembly built into the battery case is a power generating element 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, and a separator is formed between the positive electrode and the negative electrode in the form of a long sheet coated with an active material. It is classified into a jelly-roll type in which a plurality of anodes and cathodes are interposed and wound, and a stack type in which multiple anodes and cathodes are sequentially stacked with a separator interposed between them.

Among these, in particular, the usage of pouch-type batteries, which have a stacked or stacked/folded electrode assembly built into a pouch-type battery case of aluminum laminated sheets, is gradually increasing due to low manufacturing costs, small weight, and easy deformation. It is increasing.

Figure 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.

Referring to Figures 1 and 2, the conventional battery cell 10 is a battery case in which the electrode assembly 11 is mounted in the receiving part 21 and includes a sealing part 25 whose outer periphery is sealed. 20). In addition, the battery cell 10 is electrically connected to the electrode tab 15 included in the electrode assembly 11, and has an electrode lead ( 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 battery cells increases recently, there is a problem that the amount of gas generated inside the battery cell also increases. In the case of the conventional battery cell 10, it does not contain any parts that can discharge the gas generated inside the battery cell, so a venting phenomenon in which the battery case 20 bursts due to gas generation may occur during long-term storage. . In addition, moisture can penetrate into battery cells damaged by venting, which can cause side reactions, reduce battery performance, and generate additional gas. Accordingly, the need to develop battery cells with improved external emissions of gases generated inside the battery cell is increasing.

The problem to be solved by the present invention is to provide a battery cell with improved sealing strength and safety while improving the external emission of gas generated inside the battery cell, and a battery cell manufacturing device for manufacturing the same.

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

A battery cell according to an embodiment of the present invention includes a battery case including a sealing portion in which an electrode assembly is mounted in a receiving portion and the outer periphery is sealed; an electrode lead electrically connected to the electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing portion; and a lead film positioned at a portion corresponding to the sealing portion at at least one of an upper and lower portion of the electrode lead, wherein the lead film includes a first step protruding in a direction opposite to the direction toward the electrode lead. The sealing part includes a second step portion surrounding an outer surface of the first step portion, and a gas discharge guide portion is inserted into the first step portion.

The first step of the first step portion and the second step of the second step portion may each have a size corresponding to the height of the gas discharge guide portion.

The first step and the second step may have the same size.

The gas discharge guide may be located at the center of the electrode lead based on the width direction of the lead film.

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

An end of the gas discharge guide portion 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 portion and the lead film.

The adhesive force between the gas discharge inducing portion and the lead film may be smaller than at least one of an adhesive force between the lead film and an electrode lead and an adhesive force between the lead film and the sealing portion.

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

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

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

The second step portion may have a uniform thickness.

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

The adhesive force between the gas discharge inducing portion and the lead film may be smaller than the adhesive force between the adhesive layer and the gas exhaust inducing portion and the adhesive force between the adhesive layer and the electrode lead.

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

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

The moisture penetration amount of the lead film may be 0.02 g to 0.2 g for 10 years at 25°C and 50%RH.

The gas permeability of the gas discharge inducing portion may be 40 barrer or more at 60°C.

A battery cell manufacturing apparatus according to another embodiment of the present invention manufactures the battery cell described above and includes a sealing tool that seals the sealing part, the electrode lead, and the lead film together, and the sealing tool is It includes a third step portion concavely formed in a direction opposite to the direction facing the sealing portion, wherein the third step portion surrounds an outer surface of the first step portion, and the third step portion is positioned between the third step portion and the outer surface of the first step portion. 2 A step is located.

The first step of the first step portion, the second step of the second step portion, and the third step of the third step portion may each have a size corresponding to the height of the gas discharge guide portion.

The first to third steps may have the same size.

According to embodiments, the present invention provides a battery cell in which step portions are formed on the lead film and the sealing portion, respectively, and a battery cell manufacturing device for manufacturing the same, thereby increasing sealing strength and safety while reducing the gas generated inside the battery cell. External emissions can be improved.

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

According to another aspect of the present invention, even though the first step is formed on the lead film, the sealing part also has a second step formed at a position corresponding to the first step, thereby forming a seal between the sealing part and the lead film. Strength can be improved. In addition, depending on the high sealing strength between the sealing part and the lead film, the vent pressure when gas generated in the battery cell is discharged to the outside can also be increased, and safety 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 can be controlled by adjusting the shape of the gas discharge guide portion. Additionally, if necessary, the shape of the gas discharge guide can be changed to simplify the manufacturing process and reduce costs.

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

According to another aspect of the present invention, a battery cell manufacturing apparatus capable of manufacturing a battery cell in which a first step is formed on a lead film and a sealing portion and a second step is formed at a position corresponding to the first step. may be provided. According to this battery cell manufacturing apparatus, a battery cell can be manufactured without forming an over-ring part on the sealing part, thereby preventing a decrease in the sealing strength between the over-ring part and the lead film when the over-ring part is formed. You can. As the sealing strength between the sealing part and the lead film can be maintained high, the vent pressure when the gas generated within the battery cell is discharged to the outside can also be increased, making it possible to manufacture a battery cell with improved safety. do.

The effects of the present invention are not limited to the effects described above, and effects not mentioned can be clearly understood by those skilled in the art from this specification and the attached drawings.

Figure 1 is a top view of a conventional battery cell.
Figure 2 is a cross-sectional view taken along the aa' axis in Figure 1.
Figure 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 double-dashed line area of FIG. 3.
Figure 5 is a cross-sectional view taken along the BB' axis of Figure 4.
Figure 6 is a cross-sectional view taken along the AA' axis of Figure 3.
Figure 7 shows various shapes of the gas discharge guide.
FIG. 8 is an enlarged view of the double-dashed line area of FIG. 6.
FIG. 9 is a diagram showing a gas discharge path formed between the lead film of FIG. 8 and the interface of the gas discharge inducing portion.
Figure 10 is a cross-sectional view taken along the BB' axis of Figure 4 in a battery cell according to another embodiment of the present invention.
FIG. 11 is a cross-sectional view taken along the AA′ axis of FIG. 3 in the battery cell having the cross-section of FIG. 10.
FIG. 12 is an enlarged view of the double-dashed line area of FIG. 11.
FIG. 13 is a diagram showing a gas discharge path formed between the lead film of FIG. 12 and the interface of the gas discharge inducing portion.
Figure 14 is a diagram showing a battery cell manufacturing apparatus and a battery cell manufactured using the battery cell manufacturing apparatus according to another embodiment of the present invention.
Figure 15 is a diagram showing a battery cell manufacturing apparatus according to a comparative example and a battery cell manufactured therefrom.

Hereinafter, with reference to the attached drawings, various embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. The invention may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts that are not relevant to the description are omitted, and identical or similar components are given the same reference numerals throughout the specification.

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

In addition, throughout the specification, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

In addition, throughout the specification, when referring to “on a plane,” this means when the target portion is viewed from above, and when referring to “in cross-section,” this means when a cross section of the target portion is cut vertically and viewed from the side.

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

Figure 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 double-dashed line area of FIG. 3.

Referring to Figures 3 and 4, the battery cell 100 according to an embodiment of the present invention includes an electrode assembly 110 mounted on the receiving part 210 and a sealing part (sealing part) whose outer periphery is sealed. Battery case (200) including 250); An electrode lead 300 that is electrically connected to the electrode tab 115 included in the electrode assembly 110 and protrudes outward from the battery case 200 via the sealing portion 250; and a lead film 400 located in 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 along the there is. An electrode lead 300 may be formed on the short side of the battery cell 100. These battery cells 100 are integrated in the Z-axis direction and have an efficient structure for increasing energy density by stacking multiple battery cells 100 face-to-face.

The battery case 200 may be a laminated sheet including a resin layer and a metal layer. More specifically, the battery case 200 is made of a laminated sheet and may be composed of an outer resin layer forming the outermost layer, a barrier metal layer to prevent penetration of substances, and an inner resin layer for sealing.

The electrode assembly 110 may have a jelly-roll type (rolled type), stack type (laminated type), or composite type (stacked/folded type) structure. More specifically, the electrode assembly 110 may be composed of an anode, a cathode, and a separator disposed between them.

The electrode lead 300 is electrically connected to the electrode tab 115 included in the electrode assembly 110, and protrudes outward from the battery case 200 via the sealing portion 250. Additionally, the lead film 400 is located in a portion corresponding to the sealing portion 250 at least one of the upper and lower portions of the electrode lead 300. Accordingly, the lead film 400 prevents short circuits from occurring in the electrode lead 300 during heat fusion or press fusion together with the sealing part 250, while maintaining the sealing properties of the sealing part 250 and the electrode lead 300. can be improved.

Referring to FIGS. 3 and 4 , the lead film 400 may have a wider width than the electrode lead 300 . Here, the width of the lead film 400 refers to the maximum value of the distance between one end and the other end of the lead film 400 in the 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 refers to the maximum value of the distance between one end and the other end of the electrode lead 300 in a direction perpendicular 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 and a length smaller than the length of the electrode lead 300 based on the protrusion direction of the electrode lead 300. Here, the length of the lead film 400 refers to the maximum 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 refers to the maximum 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 refers to 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 can prevent the side of the electrode lead 300 from being exposed to the outside without interfering with the electrical connection of the electrode lead 300.

Figure 5 is a cross-sectional view taken along the B-B' axis in Figure 4.

Referring to Figures 4 and 5, the lead film 400 includes a first step portion 400p protruding in a direction opposite to the direction toward the electrode lead 300, and gas within the first step portion 400p. A discharge guide part 450 is inserted.

Here, the first step portion 400p may refer to a portion that protrudes in a direction opposite to the direction toward the electrode lead 300, based on the contact surface between the lead film 400 and the sealing portion 250. More specifically, the first step portion 400p may refer to a portion that protrudes in a direction opposite to the direction toward the electrode lead 300 at the position where the gas discharge guide portion 450 is inserted. In other words, in the lead film 400, the first step portion 400p is a portion where a step is created between the portion where the gas discharge guide portion 450 is inserted and the portion where the gas discharge guide portion 450 is not inserted. It can mean.

Additionally, the sealing portion 250 includes a second step portion 250p surrounding the outer surface of the first step portion 400p. Here, the second step portion 250p may refer to a portion that protrudes along the protruding direction of the first step portion 400p, with respect to the surface where the lead film 400 and the sealing portion 250 contact each other. More specifically, the second step portion 250p may refer to a portion that protrudes along the protrusion direction of the first step portion 400p at the location where the first step portion 400p is formed. In other words, in the sealing portion 250, the second step portion 250p is a portion where a step is created between the portion where the first step portion 400p is formed and the portion where the first step portion 400p is not formed. It can mean.

According to the above configuration, in this embodiment, although the first step portion 400p is formed on the lead film 400, the sealing portion 250 is also positioned at a position corresponding to the first step portion 400p. Since two step portions 250p are formed, the sealing strength between the sealing portion 250 and the lead film 400 can be improved. In addition, according to the high sealing strength between the sealing part 250 and the lead film 400, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be increased, and safety is also increased. It can be improved.

Additionally, in the lead film 400 and the sealing portion 250, the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p are not limited in size. However, it may have a size corresponding to the thickness (height in the D and Z-axis directions) of the gas discharge guide portion 450. More specifically, the first step d2 and the second step d2 may be equal to, larger than, or smaller than the thickness D of the gas discharge guide portion 450, respectively. For example, the first step d1 and the second step d2 may each have the same size as the thickness D of the gas discharge guide portion 450. As another example, the first step d1 and the second step d2 may have a size of 50% to 150% of the thickness D of the gas discharge guide portion 450.

Accordingly, in this embodiment, the first step portion 400p on the lead film 400 and the second step portion 250p of the sealing portion 250 correspond to the thickness D of the gas discharge guide portion 450. It can have a size that increases the sealing strength between the sealing part 250 and the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside, and safety can also be improved. You can.

More preferably, the first step d1 of the first step portion 400p and the second step d2 of the second step portion 250p have the same size, and each has the same thickness as the gas discharge guide portion 450. It may be the same as (D).

Accordingly, in this embodiment, the sealing strength between the sealing part 250 and the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be increased, and safety can also be increased. It can be improved further.

On the other hand, when the second step d2 has a size larger or smaller than the first step d1, an unsealed portion or an oversealed portion occurs between the lead film 400 and the sealing portion 250. As a result, the sealing strength between the sealing part 250 and the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside may be lowered, and safety may also be reduced.

Additionally, in the sealing portion 250, the thickness of the second step portion 250p may be formed to be uniform. More specifically, in the sealing portion 250, the second step portion 250p may surround the outer surface of the lead film 400 with the same thickness. In other words, in the sealing portion 250, the thickness of the second step portion 250p may surround the outer surface of the first step portion 400p with the same thickness.

Accordingly, in this embodiment, despite the first step portion 400p being formed on the lead film 400, the sealing portion 250 can wrap the outer surface of the lead film 400 with a uniform thickness. , the sealing strength between the sealing part 250 and the lead film 400 and the rate of change in thickness of the sealing part 250 before and after sealing can be maintained uniformly. That is, the portion where the sealing strength is relatively weak between the sealing portion 250 and the lead film 400 can be minimized, and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be increased. , safety can also be improved.

The thickness D of the gas discharge guide part 450 may be 50 ㎛ to 150 ㎛. When the thickness of the gas discharge guide portion 450 satisfies the above-mentioned range, it may be easier for gas inside the battery case 200 to be discharged to the outside.

Referring to FIGS. 4 and 5 , the gas discharge guide 450 may be located on the electrode lead 300. More specifically, the gas discharge guide portion 450 may be located on the center of the electrode lead 300 based on the width direction of the lead film 400. In other words, the first step portion 400p and the second step portion 250p are located on the center of the electrode lead 300 based on the width direction of the lead film 400, and the gas discharge guide portion 450 is located at the first step portion 400p and the second step portion 250p. It may be inserted into the step portion 400p.

Accordingly, in the lead film 400, the gas discharge guide portion 450 is located on the electrode lead 300, so that the gas discharge guide portion 450 may have a relatively large area, and the gas discharge guide portion 450 The amount of gas emitted can also be effectively increased.

FIG. 6 is a cross-sectional view taken along the A-A' axis of FIG. 3.

Referring to FIGS. 4 and 6 , the gas discharge guide portion 450 may extend along the protruding direction of the electrode lead 300. More specifically, in the gas discharge guide part 450, an end of the gas discharge guide part 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 portion 450 adjacent to the outside of the battery case 200 may not be exposed to the outside of the battery case 200.

Additionally, the end of the gas discharge guide portion 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 inducing portion 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 positioned on the same vertical line as the end of the lead film 400, or is positioned at a lower angle than the end of the lead film 400. It may be located on the medial side.

Accordingly, in the lead film 400, one end of the gas discharge guide portion 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 guide portion 450 adjacent to the inside of the battery case 200 is exposed to the inside of the battery case 200, so that the gas discharge formed by the gas discharge guide portion 450 The path allows gas generated within the battery cell 100 to easily flow in and be effectively discharged to the outside.

Referring further to FIG. 6, the thickness (height in the H and Z-axis directions) of the lead film 400 on the upper surface of the gas discharge guide 450 may be 100 ㎛ to 300 ㎛, or 100 ㎛ to 200 ㎛. . When the thickness H of the lead film 400 satisfies the above-mentioned range, it may be easier for gas inside the battery case 200 to be discharged to the outside.

Also, referring to FIG. 6, based on the protrusion direction of the electrode lead 300, the width (W) of the lead film 400 surrounding the front surface of the gas discharge guide 450 is 2 mm or more, or 2 mm to 3 mm. It can be. When the width (W) of the lead film 400 satisfies the above-mentioned range, the lead film 400 can be prevented from being torn as much as possible during the process in which gas generated inside the battery case 200 is discharged to the outside.

Additionally, Figure 7 shows various shapes of the gas discharge guide portion. The gas discharge guide portion 450 may be formed in a predetermined pattern to discharge gas inside the battery case 200.

As an example, the gas discharge guide portion 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 to this, and the gas discharge guide part 450 may have various shapes, such as a circular shape as shown in (a) of FIG. 7, an oval shape as shown in (b) of FIG. 7, and other linear or curved shapes.

As another example, the gas discharge guide portion 450 is connected to the first gas discharge guide portion 450a extending along the protrusion direction of the electrode lead 300 as shown in (c) of FIG. 7 and the protrusion direction of the electrode lead 300. It may include a second gas discharge guide portion 450b extending in a vertical direction. 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 outside of the sealing part 250 with respect to the sealing part 250, as shown in (c) of FIG. 7, or is located inside the lead film 400 in FIG. As shown in (d), it may be located on the inside of the sealing part 250 and on the outside of the lead film 400 based on the sealing part 250. Alternatively, the second gas discharge guide portion 450b may be located both outside and inside the lead film 400 with respect to the sealing portion 250, as shown in (e) of FIG. 7 . However, the shape of the gas discharge guide 450 is not limited to the above-described content, and may be inserted into the lead film 400 in an appropriate shape.

Accordingly, by adjusting the shape of the gas discharge guide portion 450 inserted into the lead film 400, the gas discharge performance of the gas discharge guide portion 450 and the durability and airtightness of the lead film 400 can be controlled. Additionally, if necessary, the shape of the gas discharge inducing part 450 can be changed to simplify the manufacturing process and reduce costs.

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

Accordingly, by adjusting the number of gas discharge guide portions 450 inserted into the lead film 400, the gas discharge performance of the gas discharge guide portion 450 and the durability and airtightness of the lead film 400 can be controlled. Additionally, if necessary, the number of gas discharge guide units 450 can be minimized to simplify the manufacturing process and reduce costs.

FIG. 8 is an enlarged view of the double-dashed line area of FIG. 6. FIG. 9 is a diagram showing a gas discharge path formed between the lead film of FIG. 8 and the interface of the gas discharge inducing portion. In Figure 9, the gas movement path is indicated by a dotted arrow.

Referring to FIGS. 8 and 9 , in this embodiment, a gas discharge path may be formed at the interface between the gas discharge guide 450 and the lead film 400. More specifically, as shown in FIG. 9, the gas discharge path is such that at least a portion of the interface between the gas discharge inducing portion 450 and the lead film 400 is spaced apart from each other by the pressure of the gas generated in the battery case 200. It can mean space. That is, as shown in the direction of the dotted arrow in FIG. 9, the gas discharge path means a path through which gas flows into and is discharged to the outside of a space spaced apart from each other at the interface between the gas discharge inducing portion 450 and the lead film 400. You can.

Here, the adhesive force between the gas discharge inducing portion 450 and the lead film 400 is greater than the adhesive force between the lead film 400 and the electrode lead 300 and/or the adhesive force between the lead film 400 and the sealing portion 250. It can be small. More specifically, when the pressure inside the battery case 200 increases due to the gas generated within the battery cell 100, the adhesive force of the interface between the gas discharge inducing part 450 and the lead film 400 is the lead film ( 400) and other components are relatively smaller than the adhesive force, and as shown in FIG. 9, at least part of the interface between the gas discharge guide 450 and the lead film 400 is caused by the pressure of the gas generated in the battery cell 100. may be separated from each other.

That is, in this embodiment, due to the relatively low adhesive force between the gas discharge guide portion 450 and the lead film 400, the gas discharge guide portion 450 and the lead film 400 are separated, causing the gas discharge guide portion 450 and the lead film 400 to separate. 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 this gas discharge passage and is finally discharged through the lead film 400. It can be. Gas flowing into the gas discharge passage may be discharged to the outside depending on the pressure difference with the outside.

However, in the gas discharge path, as shown in FIG. 9, the interface between the upper surface of the gas discharge inducing part 450 and the lead film 400 and the interface between the lower surface of the gas emission inducing part 450 and the lead film 400 are spaced apart. In addition to the case where the interface between the upper surface of the gas discharge inducing part 450 and the lead film 400 or the interface between the lower surface of the gas emission inducing part 450 and the lead film 400 are spaced apart, it can also be included. there is.

As an example, the gas discharge guide 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 450 may be a coating layer made of liquid resin. However, the shape of the gas discharge guide 450 or the material constituting it is not limited to this, and the adhesive force of the interface between the gas discharge guide 450 and the lead film 400 is the difference between the lead film 400 and other components. Any form or material that can make the adhesive strength relatively lower can be included in this embodiment.

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

Also, referring again to FIGS. 4 and 6 , based on the protruding direction of the electrode lead 300, one end of the gas discharge guide portion 450 may be located inside the inner surface of the sealing portion 250. In this specification, the inner surface of the sealing part 250 refers to the end of the sealing part 250 adjacent to the inside of the battery case 200, and the inner surface of the sealing part 250 refers to the sealing part 250. This means that it is located inside the battery case 200 rather than on the inner side of the unit 250. When one end of the gas discharge guide part 450 is located inside the inner surface of the sealing part 250, it is not interfered with by the sealing part 250, so it can be easier for gas to flow into the gas discharge guide part 450. there is.

Additionally, based on the protruding direction of the electrode lead 300, the other end of the gas discharge guide part 450 may be located outside the outer surface of the sealing part 250. In this specification, the outer surface of the sealing part 250 refers to the end of the sealing part 250 adjacent to the outside of the battery case 200, and the term located outside the outer surface of the sealing part 250 refers to the sealing part 250. This means that it is located toward the outside of the battery case 200 rather than the outer surface of the unit 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 guide part 450. In this way, when the other end of the gas discharge guide part 450 is located outside the outer surface of the sealing part 250, the gas flowing into the gas discharge guide part 450 may be more easily discharged to the outside. For example, since the other end of the gas discharge guide part 450 is not interfered with by the sealing part 250, the gas flowing into the gas discharge guide part 450 can be more easily discharged to the outside.

Accordingly, the gas generated inside the battery cell 100 is discharged toward the gas discharge inducing portion 450, and the gas flowing into the gas discharge inducing portion 450 can be easily discharged toward the outside as shown in FIG. 9. You can. Additionally, external emissions of gas generated inside the battery cell 100 may also increase. In this way, the gas generated inside the battery case 200 can easily flow into the gas discharge guide part 450 and be more easily discharged outside the gas discharge guide part 450.

In addition, as shown in FIG. 9 , the gas flowing into the gas discharge guide part 450 may be particularly easily discharged along the Z-axis direction through the lead film 400 on the gas discharge guide part 450. For example, when the other end of the gas discharge guide part 450 is located outside the outer surface of the sealing part 250, the gas flowing into the gas discharge guide part 450 is connected to the other end of the gas discharge guide part 450 and the sealing part. It may be discharged along the Z-axis direction from the portion of the lead film 400 between the outer surfaces of 250 . As mentioned earlier, the thickness (H) of the lead film 400 on the upper surface of the gas discharge guide 450 may be 100 ㎛ to 300 ㎛, and based on the protrusion direction of the electrode lead 300, the gas discharge guide 450 The width (W) of the lead film 400 surrounding the front surface of 450 may be 2 mm or more, or 2 mm to 3 mm. When the other end of the gas discharge inducing part 450 is located outside the outer surface of the sealing part 250 as described above, gas is discharged through the part located in the Z-axis direction, which is a relatively thin part of the lead film 400. It can be done. Therefore, gas exhaust is easier. In addition, when gas discharge occurs, if the sealing part 250 completely blocks the gas discharge path, gas discharge is not smooth, so as shown in the example, the outer surface of the sealing part 250 and the other end of the gas discharge inducing part 450 Leaving a gap (P) between them has the effect of smoothing out gas emissions.

In addition, the gas discharge inducing part 450 may further include a material having a function of absorbing or adsorbing moisture introduced from the outside or hydrofluoric acid generated internally. More specifically, the gas discharge guide 450 may further include a getter material. Here, a getter material may refer to a material capable of vacuum evacuation using the action of gas adsorption by a chemically activated metal film. As an 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 metal organic framework (MOF) structure. However, the getter material is not limited to this and may include all types of materials that are generally classified as getter materials.

Accordingly, in this embodiment, the gas discharge guide part 450 further includes a material capable of absorbing or adsorbing moisture or hydrofluoric acid, so that the gas discharge guide part 450 flows from the outside of the battery cell 100 to the inside of the battery cell 100. The permeability of incoming moisture or hydrofluoric acid can be further minimized. In one embodiment of the present invention, the gas permeability of the gas discharge inducing part 450 may be 40 barrer or more at 60°C. For example, the carbon dioxide permeability of the gas discharge inducing part 450 may satisfy the above-mentioned range.

For example, the gas discharge inducing part 450 may include at least one material selected from the group consisting of polyolefin-based, fluorine-based, and porous ceramic-based materials that satisfy the above-mentioned gas permeability value. The polyolefin-based material may include one or more materials selected from the group consisting of polypropylene, polyethylene, and polyvinyldifluoride (PVDF). The fluorine-based material may include one or more materials 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 above-mentioned range. Additionally, based on the thickness (H) of the lead film 400 of 200 ㎛, gas permeability may satisfy the above-mentioned range at 60°C. When the gas permeability of the lead film 400 satisfies the above-mentioned range, gas generated inside the battery cell can be discharged more effectively.

In this specification, gas permeability can be measured by 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 for 10 years at 25°C and 50%RH. When the moisture penetration amount of the lead film 400 satisfies the above-mentioned range, it may be more effective to prevent moisture from entering 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 moisture penetration amount of 0.02 g to 0.2 g at 25°C and 50%RH for 10 years. When the gas permeability and moisture penetration amount of the lead film 400 satisfy the above-mentioned ranges, it can be more effective in preventing moisture penetration from the outside while discharging gas generated inside the battery cell 100.

The amount of moisture penetration into the lead film 400 can 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 polyolefin-based material, epoxy, and polyvinyl chloride (PVC). The polyolefin-based material may be polyethylene (PE), polypropylene (PP), etc. For example, the lead film 400 may be made of polyethylene, polypropylene, etc. that satisfy the above-mentioned gas permeability and/or moisture penetration values.

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

Below, a battery cell according to another embodiment of the present invention will be described. However, the battery cell according to this embodiment can be described mostly in the same way as the battery cell 100 described above, and the battery cell 100 and the gas discharge inducing portion 450 inserted into the lead film 400 The explanation will focus on the areas where there are differences.

Figure 10 is a cross-sectional view taken along the B-B' axis of Figure 4 in a battery cell according to another embodiment of the present invention.

Referring to FIG. 10, in this embodiment, unlike FIG. 5, the gas discharge guide 450' may be located on the electrode lead 300'. More specifically, a separate lead film 400' may not be positioned between the gas discharge inducing portion 450' and the electrode lead 300'. That is, the gas discharge guide portion 450' is inserted into the first step portion 400p' of the lead film 400' and may be located adjacent to the electrode lead 300'. In other words, the present embodiment may have a structure in which the lead film 400' surrounds the outer surface of the gas discharge guide 450' after the gas discharge guide 450' is attached or fixed to the electrode lead 300'.

Accordingly, as the gas discharge guide portion 450' is located adjacent to the electrode lead 300', the thickness of the lead film 400' surrounding the gas discharge guide portion 450' can also be relatively reduced, resulting in manufacturing costs. There is an advantage in that the manufacturing process is easy as this is reduced.

Additionally, an adhesive layer 470' may be formed between the gas discharge inducing portion 450' and the electrode lead 300'. Here, the adhesive layer 470' may extend along the interface between the gas discharge guide 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 guide 450' and the electrode lead 300'.

For example, the adhesive layer 470' may be made of adhesive tape or adhesive binder. However, it is not limited to this, and any material that has adhesive properties capable of fixing the gas discharge guide portion 450' and the electrode lead 300' to each other can 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 relatively high adhesive strength is formed between the gas discharge inducing portion 450' and the electrode lead 300', thereby preventing peeling due to an increase in the internal pressure of the battery cell 100. , the sealing strength of the battery cell 100 can also be further improved.

FIG. 11 is a cross-sectional view taken along the A-A' axis of FIG. 3 in the battery cell having the cross-section of FIG. 10. FIG. 12 is an enlarged view of the double-dash line area of FIG. 11. FIG. 13 is a diagram showing a gas discharge path formed between the lead film of FIG. 12 and the interface of the gas discharge inducing portion. In Figure 13, the gas movement path is indicated by a dotted arrow.

Referring to FIGS. 11 to 13 , similar to FIGS. 6 to 9 , in this embodiment, a gas discharge path may be formed at the interface between the gas discharge guide 450' and the lead film 400'. However, in this embodiment, unlike FIGS. 6 to 9, the gas discharge inducing portion 450' is located adjacent to the electrode lead 300', and an adhesive layer is formed between the gas discharge inducing portion 450' and the electrode lead 300'. Since (470') is formed, a gas discharge path may not be formed at the interface between the gas discharge guide portion 450' and the electrode lead 300'.

More specifically, in this embodiment, the adhesive force between the gas discharge inducing portion 450' and the lead film 400' is the adhesive force between the adhesive layer 470' and the gas exhaust inducing portion 450' and/or the adhesive layer 470'. ) may be smaller than the adhesive force between the electrode lead 300'.

More specifically, in this embodiment, when the pressure inside the battery cell 100 increases, the adhesive force of the interface between the gas discharge inducing portion 450' and the lead film 400' has a different configuration from that of the lead film 400'. It is relatively smaller than the adhesive force between elements, and as shown in FIG. 13, at least a portion of the interface between the gas discharge guide 450' and the lead film 400' may be spaced apart from each other due to the internal pressure of the battery cell 100.

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

That is, in this embodiment, the gas discharge path can be formed by peeling only at the interface between the gas discharge inducing portion 450' and the lead film 400', thereby maintaining the gas discharge performance by the gas discharge path while maintaining the battery cell ( 100) can increase the sealing strength. Additionally, depending on the high sealing strength, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be higher, and safety can also be improved.

Hereinafter, a description will be given focusing on a battery cell manufacturing apparatus and a battery cell manufactured using the same according to another embodiment of the present invention. In the case of this embodiment, it will be described based on the embodiment shown in FIGS. 3 to 9, but the embodiment shown in FIGS. 10 to 13 may also be described in the same way.

Figure 14 is a diagram showing a battery cell manufacturing apparatus and a battery cell manufactured through the same according to another embodiment of the present invention.

Referring to FIG. 14, the battery cell manufacturing apparatus according to another embodiment of the present invention manufactures the battery cell 100 and seals the sealing portion 250, the electrode lead 300, and the lead film 400 together. Includes a sealing tool (1000). Here, the sealing tool 1000 may seal the sealing part 250, the electrode lead 300, and the lead film 400 by heat fusion or press fusion.

In addition, the sealing tool 1000 includes a third step portion 1000r concavely formed in a direction opposite to the direction facing the sealing portion 250, and the third step portion 1000r is a first step portion 400p. A second step portion 250p may be positioned between the third step portion 1000r and the outer surface of the first step portion 400p. More specifically, the sealing tool 1000 presses the sealing part 250, which extends long as shown in Figure 14(a), as the third step part 1000r presses the sealing part 250, as shown in Figure 14(b). ), a second step portion 250p may be formed between the first step portion 400p and the third step portion 1000r.

Here, the third step portion 1000r may refer to a concave portion formed in the opposite direction to the direction facing the sealing portion 250, based on the surface where the sealing tool 1000 and the sealing portion 250 are in contact. . More specifically, based on the position where the first step portion 400p is formed in the lead film 400, the third step portion 1000r is formed concavely in the opposite direction to the direction facing the sealing portion 250. It can mean part. In other words, in the sealing tool 1000, the third step portion 1000r is a portion where a step is created between the portion where the first step portion 400p is formed and the portion where the first step portion 400p is not formed. It can mean.

According to the above configuration, in this embodiment, although the first step portion 400p is formed on the lead film 400, the third step portion 1000r of the sealing tool 1000 is the first step portion ( Since the second step portion 250p can be formed at a position corresponding to 400p, the sealing strength between the sealing portion 250 and the lead film 400 can be improved. In addition, according to the high sealing strength between the sealing part 250 and the lead film 400, the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be increased, and safety can also be improved. there is.

Additionally, referring to FIGS. 5 and 14 , in the sealing tool 1000, the third step d3 of the third step portion 1000r is gas-sensitive together with the first step d1 and the second step d2, respectively. It may have a size corresponding to the thickness (D) of the discharge guide portion 450. More specifically, the third step d3 may be the same as or larger or smaller than the gas discharge inducing part 450. For example, the first step d1 to the third step d3 may have the same size. As another example, the third step d3 may have a size of 50% to 150% of the thickness D of the gas discharge guide portion 450.

Accordingly, in this embodiment, the third step 1000r of the sealing tool 1000 may have a size corresponding to the thickness D of the gas discharge inducing part 450, and is connected to the first step 400p. They may have similar sizes, and the second step portion 250p of the sealing portion 250 may also have a similar size to the first step portion 400p. That is, the thickness of the second step portion 250p of the sealing portion 250 can be formed uniformly along the outer surface of the first step portion 400p, thereby forming a seal between the sealing portion 250 and the lead film 400. The strength and the rate of change in thickness of the sealing portion 250 before and after sealing can be maintained uniformly. Additionally, the sealing strength between the lead films 400 and the vent pressure when gas generated within the battery cell 100 is discharged to the outside can be increased, and safety can also be improved.

More preferably, the first step d1 to the third step d3 may have the same size and be equal to the thickness D of the gas discharge guide portion 450.

Accordingly, in this embodiment, the sealing strength between the sealing part 250 and the lead film 400 and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside can also be increased, and safety can also be increased. It can be improved further.

In contrast, when the third step d3 has a size larger or smaller than the first step d1, the thickness of the second step d2 of the sealing portion 250 may not be formed uniformly. In particular, applying an excessively high pressure to the sealing part 250 may cause the thickness to become thin, or applying an excessively low pressure to the sealing part 250 may cause an unsealed area to occur, causing the sealing part 250 and the lead film 400 to be damaged. The sealing strength and the vent pressure when the gas generated in the battery cell 100 is discharged to the outside may be lowered, and safety may also be reduced. Figure 15 shows a battery cell manufacturing device according to a comparative example and a device manufactured using the same. This is a diagram showing a battery cell.

Referring to FIG. 15, the battery cell manufacturing apparatus according to the comparative example is the same as the battery cell manufacturing apparatus 1000 described above, except that the sealing tool 1001 does not include the third step portion 1000r. It can be explained.

Referring to FIG. 15, in the battery cell manufacturing apparatus according to the comparative example, when the third step portion 1000r is not formed in the sealing tool 1001 at a position corresponding to the first step portion 400p, FIG. As shown in (b), a false ring portion 250a may be formed in the sealing portion 250.

More specifically, as shown in FIG. 15(a), the sealing tool 1001 has steps having the same height at each position even though the first step portion 400p is formed in the lead film 400. At this time, the sealing tool 1001 applies higher pressure to the portion of the sealing portion 250 that faces the portion protruding from the first step portion 400p. Accordingly, as shown in FIG. 15(b), the sealing portion 250 may be formed with an over-ring portion 250a having a relatively thin thickness at a portion facing the first step portion 400p.

Accordingly, like the battery cell manufacturing device according to the comparative example, the sealing tool 1001 has a step of the same height without considering the height protruding by the first step portion 400p formed on the lead film 400. By forming the over-ring part 250a on the sealing part 250, the sealing strength between the over-ring part 250a and the lead film 400 may be reduced. In addition, due to the weak sealing strength between the fruit ring portion 250a and the lead film 400, the vent pressure when gas generated in the battery cell is discharged to the outside may be lowered, and safety may also be reduced.

In contrast, in the case of the battery cell manufacturing apparatus according to the present embodiment, the sealing tool 1000 has a third step portion 1000r considering the height protruding from the first step portion 400p formed on the lead film 400. As it includes, the excess ring portion 250a as shown in FIG. 14(b) may not be formed on the sealing portion 250, and the sealing strength and safety between the sealing portion 250 and the lead film 400 are also improved. It can be.

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

The battery module described above and the battery pack containing it can be applied to various devices. These devices can be applied to 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 battery modules and battery packs containing them, which are also applicable to the present invention. falls within the scope of invention rights.

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 can also be made. It falls within the scope of invention rights.

100: battery cell
110: Electrode assembly
200: Battery case
210: storage unit
250: Sealing part
300: electrode lead
400: lead film
450: Gas discharge induction unit
1000: Battery cell manufacturing device

Claims (21)

A battery case in which an electrode assembly is mounted in a storage portion and includes a sealing portion whose outer periphery is sealed;
an electrode lead electrically connected to the electrode tab included in the electrode assembly and protruding outward from the battery case via the sealing portion; and
At least one of the upper and lower portions of the electrode lead includes a lead film located in a portion corresponding to the sealing portion,
The lead film includes a first step protruding in a direction opposite to the direction toward the electrode lead,
The sealing portion includes a second step portion surrounding the outer surface of the first step portion,
A gas discharge guide is inserted into the first step,
A battery cell in which a gas discharge path is formed at an interface between the gas discharge inducing portion and the lead film. In paragraph 1:
The first step of the first step portion and the second step of the second step portion each have a size corresponding to the height of the gas discharge inducing portion. In paragraph 2,
The first step and the second step are battery cells having the same size. In paragraph 1:
A battery cell wherein the gas discharge inducing portion is located on the center of the electrode lead based on the width direction of the lead film. In paragraph 1:
A battery cell in which the gas discharge guide portion extends along a protruding direction of the electrode lead, and an end of the gas discharge guide portion adjacent to the outside of the battery case is wrapped with the lead film. In paragraph 5,
A battery cell in which an end of the gas discharge inducing portion adjacent to the inside of the battery case is exposed to the inside of the battery case. delete In paragraph 1:
A battery cell in which the adhesive force between the gas discharge inducing portion and the lead film is smaller than at least one of the adhesive force between the lead film and the electrode lead and the adhesive force between the lead film and the sealing portion. In paragraph 8:
A battery cell in which the gas discharge inducing part is a film layer made of at least one of polyimide and polyethylene terephthalate. In paragraph 8:
The gas discharge inducing part is a battery cell that is a coating layer made of liquid resin. In paragraph 8:
The gas discharge inducing part is a getter material containing 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: In paragraph 1:
A battery cell in which the second step portion is formed to have a uniform thickness. In paragraph 1:
A battery cell in which the gas discharge inducing portion is located on the electrode lead, and an adhesive layer is formed between the gas discharge inducing portion and the electrode lead. In paragraph 13:
A battery cell wherein the adhesive force between the gas discharge inducing portion and the lead film is smaller than at least one of the adhesive force between the adhesive layer and the gas exhaust inducing portion and the adhesive force between the adhesive layer and the electrode lead. In paragraph 14:
The adhesive layer is a battery cell made of adhesive tape or 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 in which the moisture penetration amount of the lead film is 0.02 g to 0.2 g for 10 years at 25°C and 50%RH. In paragraph 1:
A battery cell having a gas permeability of the gas discharge inducing part of 40 barrer or more at 60°C. delete delete delete

Images