Patent Description:
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 of great interest as energy sources not only for mobile devices such as mobile phones, digital cameras, notebooks and wearable devices, but also for power devices such as electric bicycles, electric vehicles and hybrid electric vehicles.

Depending on the shape of a battery case, these secondary batteries are classified into a cylindrical battery and a prismatic battery in which a battery assembly is included in a cylindrical or prismatic metal can, and a pouch-type battery in which the battery assembly is included in a pouch-type case of an aluminum laminate sheet. Here, the battery assembly included in the battery case is a power element including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and capable of charging and discharging, and is classified into a jelly-roll type in which long sheet-type positive and negative electrodes coated with an active material are wound with a separator being interposed therebetween, and a stack type in which a plurality of positive and negative electrodes are sequentially stacked with a separator being interposed therebetween.

Among them, in particular, a pouch-type battery in which a stack-type or stack/folding-type battery assembly is included in a pouch-type battery case made of an aluminum laminate sheet is being used more and more due to low manufacturing cost, small weight, and easy modification.

<FIG> is a top view showing a conventional battery cell. <FIG> is a cross-sectional view, taken along the axis a-a' of <FIG>. Referring to <FIG>, a conventional battery cell <NUM> includes a battery case <NUM> having an accommodation portion <NUM> in which a battery assembly <NUM> is mounted, and a sealing portion <NUM> formed by sealing an outer periphery thereof. Here, the battery cell <NUM> includes an electrode lead <NUM> protruding out of the battery case <NUM> via the sealing portion <NUM>, and a lead film <NUM> is located between upper and lower portions of the electrode lead <NUM> and the sealing portion <NUM>.

However, as the energy density of the battery cell increases in recent years, there is a problem that the amount of gas generated inside the battery cell also increases. In the case of the conventional battery cell <NUM>, a component capable of discharging the gas generated inside the battery cell is not included, so a venting may occur in the battery cell due to gas generation. In addition, moisture may penetrate into the battery cell damaged by the venting, which may cause side reactions, and there is a problem that battery performance deteriorates and additional gas is generated. Accordingly, there is an increasing need to develop a battery cell with improved external emission of gas generated inside the battery cell.

Document <CIT> and document <CIT> disclose a pouch-type battery cell with improved gas discharge.

The present disclosure is directed to providing a battery cell with improved external emission of gas generated inside the battery cell while securing easy manufacture.

To this end, the invention relates to a battery cell according to claim <NUM>.

The battery cell after the invention may present one or more of the features of dependent claims <NUM> to <NUM>, in any technically feasible combination.

According to the embodiments, the present invention provides a battery cell, which includes a lead film having a non-adhesion portion, and a battery cell manufacturing apparatus for manufacturing the same, thereby improving the external emission of gas generated inside the battery cell while securing easy manufacture.

Hereinafter, with reference to the accompanying drawings, various embodiments of the present disclosure will be described in detail so as to be easily implemented by those skilled in the art. The present disclosure may be implemented in various different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and identical or similar components are endowed with the same reference signs throughout the specification.

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

In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, throughout the specification, when referring to "top view", it means that the target part is viewed from above, and when referring to "cross-sectional view", it means that a vertically-cut section of the target part is viewed from a side.

Hereinafter, a pouch battery cell <NUM> according to an embodiment of the present disclosure will be described. However, here, the description will be made based on one side surface of both side surfaces of the pouch battery cell <NUM>, but it is not necessarily limited thereto, and the same or similar contents may be described in the case of the other side surface.

<FIG> is a top view showing a battery cell according to an embodiment of the present disclosure.

Referring to <FIG>, the battery cell <NUM> according to this embodiment includes a battery case <NUM>, an electrode lead <NUM>, and a lead film <NUM>.

The battery case <NUM> includes an accommodation portion <NUM> in which an electrode assembly <NUM> is mounted, and a sealing portion <NUM> formed by sealing an outer periphery thereof. The sealing portion <NUM> may be sealed by heat, laser, or the like. The battery case <NUM> may be a laminate sheet including a resin layer and a metal layer. More specifically, the battery case <NUM> may be made of a laminate sheet, and may include an outer resin layer forming the outermost layer, a barrier metal layer preventing penetration of materials, and an inner resin layer for sealing.

Also, the electrode assembly <NUM> may have a structure of a jelly-roll type (winding type), a stack type (lamination type), or a composite type (stack/folding type). More specifically, the electrode assembly <NUM> may include a positive electrode, a negative electrode, and a separator disposed therebetween.

Hereinafter, the electrode lead <NUM> and the lead film <NUM> will be mainly described.

<FIG> is a perspective view showing an electrode lead included in the battery cell of <FIG>.

Referring to <FIG>, the electrode lead <NUM> is electrically connected to an electrode tab (not shown) included in the electrode assembly <NUM>, and protrudes out of the battery case <NUM> via the sealing portion <NUM>. In addition, the lead film <NUM> is located at a portion corresponding to the sealing portion <NUM> in at least one of an upper portion and a lower portion of the electrode lead <NUM>. Accordingly, the lead film <NUM> may improve the sealing properties of the sealing portion <NUM> and the electrode lead <NUM> while preventing a short circuit from occurring in the electrode lead <NUM> during thermal fusion.

<FIG> is a cross-sectional view, taken along the axis c-c' of <FIG>. <FIG> is a cross-sectional view, taken along the axis d-d' of <FIG>.

Referring to <FIG> and <FIG>, which represent the present invention, a non-adhesion portion <NUM> is formed on the outer surface of the lead film <NUM>, and the non-adhesion portion <NUM> faces the outer surface of the electrode lead <NUM>. More specifically, in the lead film <NUM>, a non-adhesion portion <NUM> may be formed on one surface of the lead film <NUM> in contact with the electrode lead <NUM>.

Here, the non-adhesion portion <NUM> may be formed during a sealing process in which the lead film <NUM> and the electrode lead <NUM> are fused to each other. More specifically, the non-adhesion portion <NUM> may be a portion in which the lead film <NUM> and the electrode lead <NUM> come into contact with each other and a relatively small amount of heat and/or pressure is applied to the lead film <NUM>. That is, in the lead film <NUM>, the non-adhesion portion <NUM> is a portion having relatively weak adhesion to the electrode lead <NUM>, and may be a non-adhesion region between the electrode lead <NUM> and the lead film <NUM>. In other words, the non-adhesion portion <NUM> is a non-adhesion region between the lead film <NUM> and the electrode lead <NUM>, which may serve as a gas discharge passage through which gas may flow.

However, in <FIG> and <FIG>, the thickness of the non-adhesion portion <NUM> is somewhat exaggerated, and in reality, the non-adhesion portion <NUM> may not have an appearance deformation of the lead film <NUM>, when viewed with the naked eye.

For example, the non-adhesion portion <NUM> may be a portion in which the electrode lead <NUM> and the lead film <NUM> are in contact with each other but are not adhered to each other. As another example, the non-adhesion portion <NUM> may have a thickness of <NUM> µm to several hundred µm. However, the thickness of the non-adhesion portion <NUM> is not limited thereto, and the non-adhesion portion <NUM> may have a thickness capable of weakening the adhesive force so as not to damage airtightness and durability between the electrode lead <NUM> and the lead film <NUM>.

More specifically, the pressure inside the battery cell <NUM> is higher than the pressure inside the non-adhesion portion <NUM>, and the resulting pressure difference may act as a driving force for the gas. At this time, the gas generated inside the battery cell <NUM> may be introduced into the non-adhesion portion <NUM> due to the above-described pressure difference. Also, since the inside of the non-adhesion portion <NUM> may have a pressure difference from the outside due to the gas introduced from the inside of the battery cell <NUM>, the gas introduced into the non-adhesion portion <NUM> may be discharged to the outside.

Accordingly, in the battery cell <NUM> according to this embodiment, the gas generated inside the battery case <NUM> may be discharged to the non-adhesion portion <NUM> according to the pressure difference with the inside of the non-adhesion portion <NUM>, and the gas introduced into the non-adhesion portion <NUM> may be discharged to the outside according to the pressure difference with the outside.

Moreover, according to an embodiment of the present invention, the degree of gas discharge in the pouch and the airtightness and durability of the pouch may be adjusted according to the thickness, location, shape, or the like of the non-adhesion portion <NUM>.

For example, referring to <FIG> and <FIG>, the lead film <NUM> may include a first lead film and a second lead film respectively positioned at an upper portion and a lower portion of the electrode lead <NUM>. In addition, the first lead film and the second lead film may be integrated with each other. For example, the first lead film and the second lead film may be fused and integrated with each other by heat, laser, or the like. Accordingly, the lead film <NUM> may improve the sealing property of the sealing portion <NUM> and the electrode lead <NUM>, while preventing the side surface of the electrode lead <NUM> from being exposed to the outside.

In addition, in the lead film <NUM>, as shown in <FIG> and <FIG>, the non-adhesion portion <NUM> may be located in at least one of the first lead film and the second lead film. In addition, as shown in <FIG> and <FIG>, the non-adhesion portion <NUM> may be located in the first lead film and the second lead film, respectively.

However, the number of the non-adhesion portion <NUM> is not limited to the above, and the non-adhesion portion <NUM> may be formed in an appropriate number for the lead film <NUM>.

Accordingly, durability and airtightness between the electrode lead <NUM> and the lead film <NUM> may be controlled by adjusting the number of the non-adhesion portions <NUM> formed on the lead film <NUM>. In addition, if necessary, by minimizing the number of the non-adhesion portion <NUM>, it is possible to simplify the manufacturing process and reduce the cost.

Referring to <FIG> and <FIG>, the battery cell <NUM> according to another embodiment of the present invention may further include a surface-deformed portion <NUM> formed on the outer surface of the electrode lead <NUM>. Here, at least a part of the surface-deformed portion <NUM> may face the non-adhesion portion <NUM>. That is, in the electrode lead <NUM>, the surface-deformed portion <NUM> may be formed to have an area equal to or larger than the surface of the non-adhesion portion <NUM> facing the electrode lead <NUM>.

Accordingly, in the process of forming the non-adhesion portion <NUM> by a battery cell manufacturing apparatus <NUM> (<FIG>), explained later, a portion of the electrode lead <NUM> where the surface-deformed portion <NUM> is formed is not in contact with the non-adhesion portion <NUM>, so it is possible to prevent a part of the lead film <NUM> from being pushed into the non-adhesion portion <NUM>. Moreover, together with the non-adhesion portion <NUM>, the surface-deformed portion <NUM> may act as a gas discharge passage in the battery case <NUM>, and thus the efficiency of internal gas discharge may be further increased.

More specifically, in the electrode lead <NUM>, the surface-deformed portion <NUM> is formed on the outer surface of the electrode lead <NUM>, and the surface-deformed portion <NUM> is located between the lead film <NUM> and the electrode lead <NUM>. More specifically, in the electrode lead <NUM>, the surface-deformed portion <NUM> may be formed at a position corresponding to the non-adhesion portion <NUM>.

The surface-deformed portion <NUM> may be formed by removing a part of the outer surface of the electrode lead <NUM>. However, in <FIG> and <FIG>, the thickness of the surface-deformed portion <NUM> is somewhat exaggerated, and in fact, the surface-deformed portion <NUM> may be formed to such a thickness that deformation is substantially not viewed with the naked eye in the appearance of the electrode lead <NUM>.

For example, the surface-deformed portion <NUM> may have a thickness of <NUM> µm to several hundred µm. However, the thickness of the surface-deformed portion <NUM> is not limited thereto, and any thickness is applicable as long as it can prevent the lead film <NUM> from being pushed without damaging the airtightness and durability between the electrode lead <NUM> and the lead film <NUM>.

Accordingly, during the sealing process in which the sealing portion <NUM>, the electrode lead <NUM>, the lead film <NUM>, and the like are fused, the electrode lead <NUM> and the lead film <NUM> are adhered to each other, but since the electrode lead <NUM> and the lead film <NUM> are partially spaced apart from each other by the surface-deformed portion <NUM>, it may serve as a gas discharge passage through which the gas may flow together with the non-adhesion portion <NUM> of the lead film <NUM>.

More specifically, the internal pressure of the battery cell <NUM> is higher than the internal pressure of the space formed in the surface-deformed portion <NUM> and the non-adhesion portion <NUM>, and the resulting pressure difference may act as a driving force for the gas. At this time, the gas generated inside the battery cell <NUM> may be introduced into the space formed in the surface-deformed portion <NUM> and the non-adhesion portion <NUM> by the above-described pressure difference. In addition, the pressure in the space formed in the surface-deformed portion <NUM> and the non-adhesion portion <NUM> may be different from the external pressure due to the gas introduced from the inside of the battery cell <NUM>, so the gas introduced into the space formed in the surface-deformed portion <NUM> and the non-adhesion portion <NUM> may be discharged to the outside.

Moreover, according to an embodiment of the present invention, as the phenomenon that the non-adhesion portion <NUM> is pushed inward is controlled by the thickness, position, shape, or the like of the surface-deformed portion <NUM>, the position, size, and the like of the non-adhesion portion <NUM> may be adjusted. In addition, according to the space formed in the surface-deformed portion <NUM> and the non-adhesion portion <NUM>, the degree of gas discharge in the pouch and the airtightness and durability of the pouch may be adjusted.

For example, a coating layer (not shown) may be formed on the outer surface of the electrode lead <NUM>. Here, the coating layer (not shown) may be a layer formed by coating the outer surface of the electrode lead <NUM>. Here, the surface-deformed portion <NUM> may be formed by removing a part of the coating layer (not shown).

More specifically, the surface-deformed portion <NUM> may be formed by etching the surface of the coating layer (not shown) or the electrode lead <NUM> by laser, UV-ozone (UvO) treatment, sputtering, or the like. However, the etching method is not limited thereto, and any process capable of forming a predetermined shape by processing the surface of the electrode lead <NUM> may be applied. Here, the coating layer (not shown) is not depicted in the drawings for convenience of description, and the outer surfaces of the electrode lead <NUM> located at both sides of the surface-deformed portion <NUM> may be described as the coating layer (not shown).

For example, the coating layer (not shown) may be made of a metal material. More specifically, the metal material may contain at least one of chrome and nickel. However, the coating layer (not shown) is not limited thereto, and may include a material generally coated on the outer surface of the electrode lead <NUM>.

Accordingly, since the surface-deformed portion <NUM> may be formed by removing the coating layer (not shown) formed on the outer surface of the electrode lead <NUM>, there is an advantage in that the surface-deformed portion <NUM> may be prepared through a relatively simple manufacturing process without requiring additional components. In addition, if the surface-deformed portion <NUM> is formed by removing the coating layer (not shown) formed on the outer surface of the electrode lead <NUM>, when the surface-deformed portion <NUM> is actually viewed with the naked eye, it is possible to minimize the deformation of the appearance of the electrode lead <NUM>.

As another example, the surface-deformed portion <NUM> may be formed by removing a part of the outer surface of the electrode lead <NUM>. For example, the surface-deformed portion <NUM> may be formed by removing a part itself corresponding to the outer surface of the electrode lead <NUM>. That is, the outer surface of the electrode lead <NUM> may have a stepped structure due to the surface-deformed portion <NUM>.

More specifically, the surface-deformed portion <NUM> may be formed by etching the outer surface of the electrode lead <NUM> by laser, UV-ozone (UvO) treatment, sputtering, or the like. However, the etching method for the surface-deformed portion <NUM> is not limited thereto, and any process capable of forming a predetermined shape by processing the surface of the electrode lead <NUM> may be applied.

Accordingly, since the surface-deformed portion <NUM> may be formed by removing the outer surface of the electrode lead <NUM>, so the surface-deformed portion <NUM> may be prepared through a relatively simple manufacturing process, and there is an advantage in that no additional parts are required.

For example, the surface-deformed portion <NUM> may be located on at least one of the upper surface of the electrode lead <NUM> or the lower surface of the electrode lead <NUM>, based on the surface of the lead film <NUM> on which the non-adhesion portion <NUM> is positioned. As shown in <FIG> and <FIG>, when the non-adhesion portion <NUM> is positioned on the first lead film, the surface-deformed portion <NUM> may be positioned on the upper surface of the electrode lead <NUM>. Conversely, when the non-adhesion portion <NUM> is positioned on the second lead film, the surface-deformed portion <NUM> may be positioned on the lower surface of the electrode lead <NUM>. In addition, as shown in <FIG> and <FIG>, when the non-adhesion portion <NUM> is positioned on the first lead film and the second lead film, respectively, the surface-deformed portion <NUM> may be located on the upper and lower surfaces of the electrode lead <NUM>, respectively. However, the number of the surface-deformed portion <NUM> is not limited to the above, and the surface-deformed portion may be formed in an appropriate number on the outer surface of the electrode lead <NUM>.

Accordingly, since the number and position of the surface-deformed portion <NUM> may be adjusted to correspond to the non-adhesion portion <NUM>, it is possible to prevent the lead film <NUM> from being pushed at the non-adhesion portion <NUM>. In addition, the surface-deformed portion <NUM> may act as a gas discharge passage together with the non-adhesion portion <NUM> to effectively increase the amount of gas discharged from the inside of the battery cell <NUM>.

<FIG> is an enlarged view showing the electrode lead and the lead film in the battery cell of <FIG>, respectively.

Referring to <FIG>, the non-adhesion portion <NUM> extends along the protruding direction of the electrode lead <NUM>. In other words, based on the protruding direction of the electrode lead <NUM>, the end of the non-adhesion portion <NUM> located adjacent to the outer side of the sealing portion <NUM> may be located inner than the end of the lead film <NUM>.

Also, the width of the non-adhesion portion <NUM> may be smaller than the width of the lead film <NUM>. In this specification, the width of the non-adhesion portion <NUM> refers to a maximum value of the distance between one end and the other end of the non-adhesion portion <NUM> based on the protruding direction of the electrode lead <NUM>, and the width of the lead film <NUM> refers to a maximum value of the distance between one end and the other end of the lead film <NUM> based on the protruding direction of the electrode lead <NUM>. Also, the non-adhesion portion <NUM> may be positioned between one end and the other end of the lead film <NUM> based on the protruding direction of the electrode lead <NUM>.

In addition, the non-adhesion portion <NUM> extends in a direction perpendicular to the protruding direction of the electrode lead <NUM>, and the length of the non-adhesion portion <NUM> may be smaller than the width of the electrode lead <NUM>. In this specification, the length of the non-adhesion portion <NUM> refers to a maximum value of the distance between one end and the other end of the non-adhesion portion <NUM> based on a direction perpendicular to the protruding direction of the electrode lead <NUM>, and the width of the electrode lead <NUM> refers to a maximum value of the distance between one end and the other end of the electrode lead <NUM> based on a direction perpendicular to the protruding direction of the electrode lead <NUM>.

For example, referring to <FIG>, the non-adhesion portion <NUM> may have a circular shape or a rectangular shape. As another example, referring to <FIG>, the non-adhesion portion <NUM> includes a first non-adhesion portion 450a and a second non-adhesion portion 450b connected to each other. The first non-adhesion portion 450a may extend along the longitudinal direction of the sealing portion <NUM>, and the second non-adhesion portion 450b may extend along the protruding direction of the electrode lead <NUM>. In this specification, the longitudinal direction of the sealing portion <NUM> refers to a direction perpendicular to the protruding direction of the electrode lead <NUM>.

Here, the length of the first non-adhesion portion 450a may be smaller than the width of the electrode lead <NUM>, and the length of the second non-adhesion portion 450b may be smaller than the width of the lead film <NUM>. In this specification, the length of the first non-adhesion portion 450a refers to a maximum value of the distance between one end and the other end of the first non-adhesion portion 450a based on a direction perpendicular to the protruding direction of the electrode lead <NUM>, the length of the second non-adhesion portion 450b refers to a maximum value of the distance between one end and the other end of the second non-adhesion portion 450b based on the protruding direction of the electrode lead <NUM>.

However, the shape of the non-adhesion portion <NUM> is not limited to the above, and the non-adhesion portion <NUM> may be formed in an appropriate shape on the outer surface of the lead film <NUM>.

Accordingly, by adjusting the shape of the non-adhesion portion <NUM> formed on the outer surface of the lead film <NUM>, the durability and airtightness between the electrode lead <NUM> and the lead film <NUM> may be controlled. In addition, by changing the shape of the non-adhesion portion <NUM> as necessary, it is possible to simplify the manufacturing process and reduce the cost.

Referring to <FIG>, in another embodiment of the present invention, the battery cell <NUM> may further include a surface-deformed portion <NUM> formed on the outer surface of the electrode lead <NUM>. Here, the surface-deformed portion <NUM> extends along the protruding direction of the electrode lead <NUM>, based on the protruding direction of the electrode lead <NUM>, and the end of the surface-deformed portion <NUM> adjacent to the outer side of the sealing portion <NUM> may be located inner than the end of the lead film <NUM>. In this specification, the outer side of the sealing portion <NUM> means the end of the sealing portion <NUM> adjacent to the outside of the battery case <NUM>. In addition, the inner side inner than the end of the lead film <NUM> means an inner side of the battery case <NUM> inner than the end of the lead film <NUM> adjacent to the outside of the battery case <NUM>.

More specifically, the width of the surface-deformed portion <NUM> may be smaller than the width of the lead film <NUM>. In this specification, the width of the surface-deformed portion <NUM> refers to a maximum value of the distance between one end and the other end of the surface-deformed portion <NUM> based on the protruding direction of the electrode lead <NUM>. Also, the surface-deformed portion <NUM> may be positioned between one end and the other end of the lead film <NUM> based on the protruding direction of the electrode lead <NUM>.

In addition, the surface-deformed portion <NUM> extends in a direction perpendicular to the protruding direction of the electrode lead <NUM>, and the length of the surface-deformed portion <NUM> may be smaller than the width of the electrode lead <NUM>. In this specification, the length of the surface-deformed portion <NUM> refers to a maximum value of the distance between one end and the other end of the surface-deformed portion <NUM> based on a direction perpendicular to the protruding direction of the electrode lead <NUM>.

Here, the surface-deformed portion <NUM> may have a shape identical or similar to that of the non-adhesion portion <NUM>.

For example, referring to <FIG>, the surface-deformed portion <NUM> may have a circular shape or a rectangular shape, like the non-adhesion portion <NUM>. As another example, referring to <FIG>, the surface-deformed portion <NUM> includes a first surface-deformed portion 350a and a second surface-deformed portion 350b connected to each other. The first surface-deformed portion 350a may extend along the longitudinal direction of the sealing portion, and the second surface-deformed portion 350b may extend along the protruding direction of the electrode lead. Here, the shape of the first surface-deformed portion 350a may correspond to the shape of the first non-adhesion portion 450a, and the shape of the second surface-deformed portion 350b may correspond to the shape of the second non-adhesion portion 450b.

For example, the width of the first surface-deformed portion 350a may be greater than or equal to the width of the first non-adhesion portion 450a, and the width of the second surface-deformed portion 350b may be greater than or equal to the width of the second non-adhesion portion 450b. In this specification, the width of the first surface-deformed portion 350a refers to a maximum value of the distance between one end and the other end of the first surface-deformed portion 350a based on the protruding direction of the electrode lead <NUM>, and the width of the first non-adhesion portion 450a refers to a maximum value of the distance between one end and the other end of the first non-adhesion portion 450a based on the protruding direction of the electrode lead <NUM>. The width of the second surface-deformed portion 350b refers to a maximum value of the distance between one end and the other end of the second surface-deformed portion 350b based on a direction perpendicular to the protruding direction of the electrode lead <NUM>, and the width of the second non-adhesion portion 450b refers to a maximum value of the distance between one end and the other end of the second non-adhesion portion 450b based on a direction perpendicular to the protruding direction of the electrode lead <NUM>.

However, the shape of the surface-deformed portion <NUM> is not limited to the above, and the surface-deformed portion <NUM> may be appropriately formed in a shape corresponding to the non-adhesion portion <NUM>.

Accordingly, since the shape of the surface-deformed portion <NUM> may be adjusted to correspond to the non-adhesion portion <NUM>, it is possible to prevent the lead film <NUM> from being pushed at the non-adhesion portion <NUM> and to effectively increase the amount of gas discharged from the inside of the battery cell <NUM>.

<FIG> is a cross-sectional view, taken along the axis b-b' of <FIG>.

Referring to <FIG>, in one embodiment of the present invention, based on the protruding direction of the electrode lead <NUM>, one end of the non-adhesion portion <NUM> may be located inner than the inner surface of the sealing portion <NUM>, and the other end of the non-adhesion portion <NUM> may be located outer than the outer surface of the sealing portion <NUM>. In this specification, the inner surface of the sealing portion <NUM> means an end of the sealing portion <NUM> adjacent to the inside of the battery case <NUM>, and one end of the non-adhesion portion <NUM> located inner than the inner surface of the sealing portion <NUM> means that one end of the non-adhesion portion <NUM> is located in the inner direction of the battery case <NUM> rather than the inner surface of the sealing portion <NUM>. If one end of the non-adhesion portion <NUM> is located inner than the inner surface of the sealing portion <NUM>, the non-adhesion portion <NUM> is not interfered by the sealing portion <NUM>, so that gas may be more easily introduced into the non-adhesion portion <NUM>. In addition, the outer surface of the sealing portion <NUM> means an end of the sealing portion <NUM> adjacent to the outside of the battery case <NUM>, and the other end of the non-adhesion portion <NUM> located outer than the outer surface of the sealing portion <NUM> means that the other end of the non-adhesion portion <NUM> is located in the outer direction of the battery case <NUM> rather than the outer surface of the sealing portion <NUM>. If the other end of the non-adhesion portion <NUM> is located outer than the outer surface of the sealing portion <NUM>, the gas introduced into the non-adhesion portion <NUM> may be more easily discharged to the outside. For example, since the other end of the non-adhesion portion <NUM> is not interfered by the sealing portion <NUM>, the gas introduced into the non-adhesion portion <NUM> may be more easily discharged to the outside.

Accordingly, the gas generated inside the battery cell <NUM> may be discharged toward the non-adhesion portion <NUM>, and the gas introduced into the non-adhesion portion <NUM> may be easily discharged toward the outside. In addition, the amount of gas generated inside the battery cell <NUM> and discharged to the outside may also be increased.

In addition, in another embodiment of the present disclosure, the battery cell <NUM> may further include a surface-deformed portion <NUM> formed on the outer surface of the electrode lead <NUM>. Here, based on the protruding direction of the electrode lead <NUM>, one end of the surface-deformed portion <NUM> may be located inner than the inner surface of the sealing portion <NUM>, and based on the protruding direction of the electrode lead <NUM>, the other end of the surface-deformed portion <NUM> may be located outer than the outer surface of the sealing portion <NUM>. If one end of the surface-deformed portion <NUM> is located inner than the inner surface of the sealing portion <NUM>, the surface-deformed portion <NUM> is not interfered by the sealing portion <NUM>, so that gas may be more easily introduced into the surface-deformed portion <NUM>. If the other end of the surface-deformed portion <NUM> is located outer than the outer surface of the sealing portion <NUM>, the gas introduced into the surface-deformed portion <NUM> may be more easily discharged to the outside. For example, since the other end of the surface-deformed portion <NUM> is not interfered by the sealing portion <NUM>, the gas introduced into the surface-deformed portion <NUM> may be more easily discharged to the outside.

Accordingly, the gas generated inside the battery cell <NUM> may be discharged toward the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM>, and the gas introduced into the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> may be easily discharged toward the outside. In addition, the amount of gas generated inside the battery cell <NUM> and discharged to the outside may also be increased.

Moreover, since both ends of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> are exposed to the inside of the battery case <NUM> and the outside of the battery case <NUM>, the gas generated inside the battery case <NUM> may be easily introduced into the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> and may also be more easily discharged to the outside of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM>.

Specifically, the gas introduced into the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> may be discharged along the Z-axis direction through the lead film <NUM> on the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM>. For example, if the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> is located outer than the outer surface of the sealing portion <NUM>, the gas introduced into the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> may be discharged along the Z-axis direction at the portion of the lead film <NUM> between the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> and the outer surface of the sealing portion <NUM>.

In one embodiment of the present disclosure, the gas permeability of the lead film <NUM> may be <NUM> Barrer to <NUM> Barrer, or <NUM> Barrer to <NUM> Barrer at <NUM>. For example, the carbon dioxide permeability of the lead film <NUM> may satisfy the above range. In addition, the gas permeability may satisfy the above range at <NUM> based on the thickness of the lead film <NUM> of <NUM>. If the gas permeability of the lead film <NUM> satisfies the above range, the gas generated inside the battery cell may be more effectively discharged.

In this specification, the gas permeability may be measured by ASTM F2476-<NUM>.

In one embodiment of the present disclosure, the moisture penetration amount of the lead film <NUM> may be <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM>, or <NUM> for <NUM> years at <NUM>, <NUM> %RH. If the moisture penetration amount of the lead film <NUM> satisfies the above range, the penetration of moisture from the lead film <NUM> may be more effectively prevented.

The moisture penetration amount of the lead film <NUM> may be measured by adopting the ASTM F <NUM> method. At this time, the moisture penetration amount may be measured using equipment officially certified by MCOON.

In one embodiment of the present disclosure, the lead film <NUM> may have a gas permeability of <NUM> Barrer to <NUM> Barrer at <NUM> and a moisture penetration amount of <NUM> to <NUM> at <NUM>, <NUM> %RH for <NUM> years. If the gas permeability and the moisture penetration amount of the lead film <NUM> satisfy the above ranges, the penetration of moisture from the outside may be more effectively prevented while discharging the gas generated inside the secondary battery.

In one embodiment of the present disclosure, the lead film <NUM> may include a polyolefin-based resin. For example, the lead film <NUM> may include a polyolefin-based resin satisfying the gas permeability and/or moisture penetration amount values described above. The polyolefin-based resin may include at least one material selected from the group consisting of polypropylene, polyethylene, and polyvinyl difluoride (PVDF). While the lead film <NUM> contains polypropylene, the gas permeability of the lead film <NUM> may be <NUM> Barrer to <NUM> Barrer at <NUM>. Also, the moisture penetration amount may be <NUM> to <NUM>. In this case, the gas generated inside the secondary battery may be more effectively discharged, and the penetration of moisture from the outside may be easily prevented.

In addition, since the lead film <NUM> is made of the above-described material, the lead film <NUM> may maintain the airtightness of the battery cell <NUM> and prevent leakage of the internal electrolytic solution.

Referring to <FIG>, the thickness (H) of the lead film <NUM> at the non-adhesion portion <NUM> may be <NUM> to <NUM>, or <NUM> to <NUM>. If the thickness (H) of the lead film <NUM> at the non-adhesion portion <NUM> satisfies the above range, the gas inside the battery case <NUM> may be more easily discharged to the outside.

Referring to <FIG>, the width (W) between the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> and the outermost end of the lead film <NUM> may be <NUM> or more, or <NUM> to <NUM>. If the width (W) between the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> and the outermost end of the lead film <NUM> satisfies the above range, it may be easier to prevent the lead film <NUM> from being torn during the process of discharging the gas generated inside the battery case <NUM> to the outside.

In one embodiment of the present disclosure, if one end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> is located inner than the inner surface of the sealing portion <NUM> and the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> is located outer than the outer surface of the sealing portion <NUM>, the area of the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> exposed outer than the outer surface of the sealing portion <NUM> may be greater than the area of one end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> exposed inner than the inner surface of the sealing portion <NUM>. The gas discharge amount is proportional to the gas discharge area and pressure. Since the pressure on the inner side of the battery case <NUM> is greater than the pressure on the outer side of the battery case <NUM>, if the area of the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> exposed outer than the outer surface of the sealing portion <NUM> is greater than the area of one end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> exposed inner than the inner surface of the sealing portion <NUM>, the gas generated inside the battery case <NUM> may be more easily discharged to the outside.

In one embodiment of the present invention, the area of the other end of the surface-deformed portion <NUM> and/or the non-adhesion portion <NUM> exposed at the outer side of the sealing portion <NUM> may be <NUM><NUM> to <NUM><NUM>. This is a size in which about <NUM> cc to <NUM> cc of gas can be discharged per day based on an internal pressure of <NUM> atm at <NUM>. In addition, this is a size in which the moisture penetration amount may be <NUM> to <NUM> for <NUM> years at <NUM>, <NUM> %RH.

<FIG> is a diagram for illustrating the process of bonding the electrode lead and the lead film by a battery cell manufacturing apparatus according to another embodiment of the present invention <FIG> is a cross-sectional view, taken along the axes e-e' and f-f' of <FIG>, respectively.

Referring to <FIG> and <FIG>, the battery cell manufacturing apparatus according to another embodiment of the present invention is an apparatus for manufacturing the battery cell <NUM>, and includes a jig <NUM> for pressing the electrode lead <NUM> and the lead film <NUM> together. Accordingly, the electrode lead <NUM> and the lead film <NUM> may be adhered to each other by heat and/or pressure applied by the jig <NUM>.

More specifically, referring to <FIG> and <FIG>, the jig <NUM> includes a concave portion <NUM> on one surface facing the lead film <NUM>. Here, the concave portion <NUM> may be formed by etching one surface of the jig <NUM>.

For example, the concave portion <NUM> may be formed by etching the outer surface of the jig <NUM> by laser, UV-ozone (UvO) treatment, sputtering, or the like. However, the etching method is not limited thereto, and any process capable of forming a predetermined shape by processing the surface of the jig <NUM> may be applied.

Referring to <FIG> and <FIG>, the jig <NUM> presses the lead film <NUM> so that a non-adhesion portion <NUM> is formed at the other surface of the lead film <NUM>, which is opposite to one surface of the lead film <NUM> facing the concave portion <NUM>. Here, the non-adhesion portion <NUM> may be formed in a shape identical or similar to that of the concave portion <NUM>.

In addition, referring to <FIG> and <FIG>, in another embodiment of the present invention, if the surface-deformed portion <NUM> is formed on the outer surface of the electrode lead <NUM>, at least a part of the surface-deformed portion <NUM> may be formed at a location facing the concave portion <NUM>. For example, the surface-deformed portion <NUM> may have a shape identical or similar to that of the concave portion <NUM>. In other words, the surface-deformed portion <NUM> may have a shape identical or similar to that of the non-adhesion portion <NUM> formed by the concave portion <NUM>.

Accordingly, even if the jig <NUM> presses the electrode lead <NUM> and the lead film <NUM>, the outer surface of the lead film <NUM> facing the surface-deformed portion <NUM> does not come into contact with the electrode lead <NUM> by the surface-deformed portion <NUM>, and thus the non-adhesion portion <NUM> may be easily formed. In addition, in this case, it is possible to prevent the lead film <NUM> from being pushed at the non-adhesion portion <NUM>.

<FIG> is a cross-sectional view substantially identical to that of <FIG>, in which a surface-deformed portion is not formed in the electrode lead.

Referring to <FIG>, in one embodiment of the present invention, even when the surface-deformed portion <NUM> is not formed on the outer surface of the electrode lead <NUM>, since the heat and/or pressure applied to the outer surface of the lead film <NUM> corresponding to the concave portion <NUM> is relatively low, the non-adhesion portion <NUM> may be formed on the other surface of the lead film <NUM>, which is opposite to one surface of the lead film <NUM> facing the concave portion <NUM>.

Accordingly, the non-adhesion portion <NUM> may be formed on the lead film <NUM> in the process of fusing the sealing portion <NUM>, the electrode lead <NUM> and the lead film <NUM> without a separate additional process for the lead film <NUM>. That is, according to this embodiment, the manufacturing process is simple, and the amount of gas discharged from the inside of the battery cell <NUM> may be effectively increased.

However, since the electrode lead <NUM> and the lead film <NUM> are in contact with each other, a part of the lead film <NUM> may be pushed into the non-adhesion portion <NUM> while the jig <NUM> presses the electrode lead <NUM> and the lead film <NUM>. Here, referring to <FIG>, a protrusion 400a may be formed in the non-adhesion portion <NUM> since a part of the lead film <NUM> is pushed.

Accordingly, in order to prevent the lead film <NUM> on which the protrusion 400a is formed in the non-adhesion portion <NUM> from being pushed and to more effectively increase the amount of gas discharged from the inside of the battery cell <NUM>, it may be more preferable that the surface-deformed portion <NUM> is formed on the outer surface of the electrode lead <NUM> as shown in <FIG>.

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

Claim 1:
A battery cell (<NUM>), comprising:
a battery case (<NUM>) having an accommodation portion (<NUM>) in which an electrode assembly (<NUM>) is mounted, and a sealing portion (<NUM>) formed by sealing an outer periphery thereof;
an electrode lead (<NUM>) electrically connected to an electrode tab included in the electrode assembly (<NUM>) and protruding out of the battery case (<NUM>) via the sealing portion (<NUM>); and
a lead film (<NUM>) located at a portion corresponding to the sealing portion (<NUM>) in at least one of an upper portion and a lower portion of the electrode lead (<NUM>),
characterized in that a non-adhesion portion (<NUM>) is formed on an outer surface of the lead film (<NUM>), and the non-adhesion portion (<NUM>) is configured to face an outer surface of the electrode lead (<NUM>).