KR102186737B1 - Battery Cell Comprising Protection Member - Google Patents

Abstract

The present invention is made of a planar square structure, the electrode assembly including a positive terminal and a negative terminal protruding to the outer periphery of one side; A battery case including a storage unit for accommodating the electrode assembly, and sealing the electrode assembly in a state of being accommodated with an electrolyte; And a protective member located between the outer surface of the electrode assembly and the inner surface of the battery case in the receiving part, and having a structure surrounding the rest of the outer periphery except for the outer periphery where the positive and negative terminals of the electrode assembly protrude in a plan view. It provides a battery cell comprising;

Description

Battery Cell Comprising Protection Member {Battery Cell Comprising Protection Member}

The present invention relates to a battery cell including a protective member.

In recent years, interest in environmental pollution and rising prices of energy sources due to depletion of fossil fuels are amplified, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor for future life. Accordingly, research on various power generation technologies such as nuclear power, solar power, wind power, and tidal power is continuing, and power storage devices for more efficient use of the energy produced in this way are also receiving great interest.

In particular, as technology development and demand for mobile devices increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, many studies on batteries that can meet various demands have been conducted.

Typically, in terms of the shape of the battery, there is a high demand for prismatic secondary batteries and pouch-type secondary batteries that can be applied to products such as mobile phones with a thin thickness, and in terms of materials, it has advantages such as high energy density, discharge voltage, and output stability. There is high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

In addition, secondary batteries are classified according to the structure of an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are stacked. Typically, long sheet-shaped positive electrodes and negative electrodes are used. A jelly-roll type (wound type) electrode assembly wound with a separator interposed therebetween, a stacked (stacked) electrode assembly in which a plurality of anodes and cathodes cut into units of a predetermined size are sequentially stacked with a separator interposed therebetween In recent years, in order to solve the problems of the jelly-roll type electrode assembly and the stack type electrode assembly, as an electrode assembly having an advanced structure, which is a mixture of the jelly-roll type and the stack type, A stack/folding electrode assembly having a structure in which the unit cells stacked with the anode and the cathode interposed between the separator and the unit cells stacked on the separation film were sequentially wound up was developed.

In addition, secondary batteries are cylindrical and prismatic batteries in which an electrode assembly is built into a cylindrical or square metal can, and a pouch-type battery in which the electrode assembly is built into a pouch-shaped case of an aluminum laminate sheet, depending on the shape of the battery case. Classified.

In particular, in recent years, a pouch-type battery having a structure in which a stack-type or stack/folding-type electrode assembly is embedded in a pouch-type battery case of an aluminum laminate sheet has attracted a lot of attention due to low manufacturing cost, small weight, and easy shape transformation. And also its usage is gradually increasing.

1 is an exploded perspective view schematically showing the structure of a conventional pouch-type battery cell.

Referring to FIG. 1, a pouch-type battery cell 100 includes an electrode assembly 130, electrode tabs 131 and 132 extending from the electrode assembly 130, and electrodes welded to the electrode tabs 131 and 132. It is configured to include a battery case 120 accommodating the leads 140 and 141 and the electrode assembly 130.

The electrode assembly 130 is a power plant in which an anode and a cathode are sequentially stacked with a separator interposed therebetween, and has a stacked or stacked/folded structure. The electrode tabs 131 and 132 extend from each electrode plate of the electrode assembly 130, and the electrode leads 140 and 141 include a plurality of electrode tabs 131 and 132 extending from each electrode plate, for example, Each is electrically connected by welding, and a part of the battery case 120 is exposed to the outside. In addition, an insulating film 150 is attached to a portion of the upper and lower surfaces of the electrode leads 140 and 141 to increase sealing degree with the battery case 120 and at the same time secure an electrical insulation state.

The battery case 120 is composed of a case body 122 including a concave storage unit 123 in which the electrode assembly 130 can be seated and a cover 121 integrally connected to the body 122 In addition, a battery is completed by combining the both side portions 124 and the upper end 125, which are contact portions, in a state in which the electrode assembly 130 is accommodated in the storage unit 123. The battery case 120 is made of an aluminum laminate structure of a resin outer layer/barrier metal layer/thermal meltable resin sealant layer, so that the cover 121 and both sides 124 and upper end 125 of the cover 121 and the main body 122 are in contact with each other. Heat and pressure are applied to the resin layers to form a bonded sealing surplus by fusing each other. Both sides 124 can be uniformly sealed by melting because the same resin layers of the upper and lower battery cases 120 are in direct contact. On the other hand, since the electrode leads 140 and 141 protrude from the upper end 125, the electrode leads 140 and 141 are protruded in order to increase the sealing property in consideration of the thickness of the electrode leads 140 and 141 and the heterogeneity of the material Thermal bonding is performed with the insulating film 150 interposed between the leads 140 and 141.

In general, a pouch-type battery cell having such a structure is manufactured through a process of removing the gas generated in the activation process by discharging it to the outside of the battery case after the activation process through charging and discharging.

At this time, in the process of removing the gas, a hole is drilled in the outer surface of the battery case and the gas is discharged using a vacuum. In this process, the pouch-type battery case is relatively weak due to its relatively weak stiffness, so that at least one part of the outer surface Deformation of the shape may increase product defects.

In particular, due to the weak stiffness of the pouch-type battery case, the battery cell is inevitably relatively weak to physical stimulation applied from the outside, such as an impact by a needle-shaped conductor, and accordingly, the battery case is an internal electrode assembly. There is a problem that cannot be safely protected.

That is, the pouch-type battery cell has the advantage of being able to configure the battery cell more compactly by being easily deformed in shape, light in weight, and thin thickness due to the characteristics of the battery case material. There is a problem in that defects are likely to occur due to deformation of the outer surface shape occurring in the manufacturing process of the cell, and the electrode assembly cannot be safely protected against physical stimuli applied from the outside, thereby deteriorating structural stability and safety.

Therefore, there is a high need for a technology that can fundamentally solve this problem.

An object of the present invention is to solve the problems of the prior art and technical problems that have been requested from the past.

The inventors of the present application, after in-depth research and various experiments, are configured to include a protective member surrounding the outer periphery of the electrode assembly, as described later, so that the manufacturing process of the battery cell, more specifically, gas discharge. It prevents the deformation of the shape of the outer surface of the battery cell caused by the vacuum applied during the process, thereby reducing the defect rate of the product, and safeguards the electrode assembly against physical stimulation applied from the outside, thereby improving structural stability. At the same time, it is possible to effectively prevent the problem of safety deterioration due to damage to the electrode assembly, and by securing a space to hold the electrolyte according to the special structure of the protective member, the problem of performance degradation due to the reduction of the electrolyte solution It was confirmed that it could be prevented, and the present invention was completed.

The battery cell according to the present invention for achieving this purpose,

An electrode assembly consisting of a planar square structure and including a positive terminal and a negative terminal protruding toward an outer periphery of one side;

A battery case including a storage unit for accommodating the electrode assembly, and sealing the electrode assembly in a state of being accommodated with an electrolyte; And

A protection member disposed between the outer surface of the electrode assembly and the inner surface of the battery case in the receiving portion, and having a structure surrounding the rest of the outer periphery except for the outer periphery where the positive and negative terminals of the electrode assembly protrude in a plan view;

It may be a structure that includes.

Therefore, it is possible to prevent deformation of the shape of the outer surface of the battery cell caused by the vacuum applied during the manufacturing process of the battery cell, and more specifically, the gas discharge process, thereby reducing the defect rate of the product, and By more safely protecting the electrode assembly against stimulation, structural stability can be improved, and at the same time, the problem of safety deterioration due to damage to the electrode assembly can be effectively prevented.

In one specific example, the protection member may be made of a metal or high-strength plastic not reactive with an electrolyte, and more specifically, may be made of stainless steel.

However, the material of the protection member is not limited thereto, and in detail, it exhibits sufficient strength to protect the outer periphery of the electrode assembly within the storage part of the battery case, and is not reactive with the electrolyte, If it does not change the performance of the battery cell, it can be appropriately selected in consideration of various factors such as ease of handling, economy, and weight.

In addition, the battery case may be a pouch-shaped case including a metal layer and a resin layer.

That is, the protective member may exhibit a more excellent effect in a battery cell including a battery case having relatively weak rigidity, such as a pouch-type case.

Meanwhile, the protection member may have a structure in which corner portions of the electrode assembly in a direction opposite to the positive terminal and the negative terminal have a round structure.

More specifically, the electrode assembly has a rectangular structure in plan, whereas the protective member has a round structure in which corners of the electrode assembly in a direction opposite to the positive terminal and the negative terminal are formed, so that the protective member has a round structure. In a state of facing the edge portion of the electrode assembly at the edge portion consisting of, it may be positioned in a structure spaced apart from the outer periphery of the electrode assembly at a predetermined interval.

Accordingly, the spaced apart space between the outer periphery of the electrode assembly and the protection member provides a space in which an electrolyte solution can be additionally located, thereby effectively preventing a problem of battery cell performance degradation due to a decrease in the electrolyte solution.

At this time, the radius of curvature of the round structure is, based on the width of the electrode assembly, which is the distance between the outer peripheries of both sides opposite to each other, among the rest of the outer peripheries excluding the outer peripheries where the positive and negative terminals of the electrode assembly protrude, 5 % To 30% of the size.

If the radius of curvature of the round structure is out of the above range and is too small, despite the round structure at the corner of the protection member, sufficient electrolyte can be additionally located between the outer periphery of the electrode assembly and the protection member. Since space cannot be provided, the effect of the round structure may not be exhibited.

Conversely, when the radius of curvature of the round structure is out of the above range and is too large, the spaced apart space between the outer periphery of the electrode assembly and the protective member may unnecessarily increase, and as a result, the size of the protective member increases. As a result, there may be a problem in that the capacity is decreased compared to the battery cells of the same size.

In one specific example, both end portions of the protective member adjacent to the outer periphery from which the positive and negative terminals of the electrode assembly protrude may have a structure that is bent and extended in the direction of the electrode assembly on a plane.

Accordingly, the electrode assembly can minimize the flow in the battery case by the end portions of both sides of the protective member adjacent to the outer periphery where the positive terminal and the negative terminal protrude, and thus, in the flow process of the electrode assembly. It is possible to prevent damage to the positive and negative terminals and the resulting internal short circuit.

In this case, both end portions of the protection member may have a structure that is bent and extended at an angle of 1° to 90° with respect to a straight line parallel to the protruding direction of the positive terminal and the negative terminal.

If both ends of the protection member are bent and extended at an angle of less than 1 degree with respect to a straight line parallel to the protruding directions of the positive and negative terminals, the desired electrode assembly through the bent and extended structure It may not be effective in preventing flow.

Conversely, when both ends of the protective member are bent and extended at an angle exceeding 90 degrees with respect to a straight line parallel to the protruding directions of the positive terminal and the negative terminal, both end portions of the bent-extended protective member By directly contacting the outer periphery of the electrode assembly, there is a problem in that an internal short circuit may occur or the electrode assembly may be damaged.

In one specific example, the end portions of both sides of the bent and extended protection member may have a structure that is located relatively outward compared to the outer circumference of the electrode assembly in which the positive and negative terminals protrude in a plane.

Accordingly, the electrode assembly may more effectively suppress the protrusion direction of the electrode terminals and/or the flow in both directions perpendicular to the protrusion direction of the electrode terminals by the end portions of both ends of the bent and extended protection member.

In this case, both end portions of the protection member may have a structure that is bent two or more times so as to surround both edges of the outer periphery of the electrode assembly in which the positive and negative terminals protrude in a plane.

Therefore, since the electrode assembly is more stably fixed and supported in the battery case by the end portions of both sides of the protective member that are bent two or more times, the flow is prevented, so that problems caused by the flow of the electrode assembly can be prevented. .

In another specific example, both end portions of the protection member may have a structure in which the positive terminal and the negative terminal protrude in a plan view, and may be bent and extended to a length corresponding to both corners of the outer periphery of the electrode assembly.

Therefore, when both end portions of the protection member are located inside compared to both corners of the outer periphery of the electrode assembly in which the positive terminal and the negative terminal protrude in a plan view, both end portions of the protective member are outside the electrode assembly. It is possible to prevent problems of internal short circuit and damage that may occur by direct contact with the surroundings.

On the other hand, the height of the protective member in the vertical section may be a structure consisting of a size of 50% to 99% of the thickness of the electrode assembly corresponding thereto.

If the height on the vertical cross-section of the protection member is less than 50% of the thickness of the electrode assembly corresponding thereto, the width of the outer periphery of the electrode assembly exposed despite the protection member is widened. , It may not be possible to safely protect the electrode assembly from external physical stimuli such as penetration by a needle-shaped conductor through the protection member.

Conversely, when the height in the vertical section of the protection member exceeds 99% of the thickness of the corresponding electrode assembly, the height in the vertical section of the protection member becomes larger than the thickness of the corresponding electrode assembly. As a result, unnecessary space may be generated in the thickness direction of the electrode assembly in the receiving part of the battery case, and thus the size of the battery cell may be unnecessarily increased, or the capacity of the battery cell may decrease compared to the battery cell of the same size. I can.

Further, the width and length of the protection member may be 101% to 130% of the width and length of the electrode assembly.

Here, the terms of the width and length refer to the distance between the outer peripheries of the electrode assembly facing each other in a direction perpendicular and parallel to the protruding direction of the electrode terminals on a plane.

If the width and length of the protective member is less than 101% of the width and length of the electrode assembly, the space between the protective member and the outer periphery of the electrode assembly is narrowed, so that an additional electrolyte is located. In contrast, when the width and length of the protection member exceeds 130% of the width and length of the electrode assembly, the size of the protection member is excessively increased, and thus the battery The size of the cell may increase unnecessarily, or the capacity of the battery cell may decrease compared to a battery cell of the same size.

In one specific example, the thickness of the protective member may be 500 micrometers to 2000 micrometers.

If the thickness of the protective member is out of the above range and is too thin, stable strength cannot be exhibited, and thus the electrode assembly may not be safely protected from external physical stimulation such as penetration by a needle-shaped member.

Conversely, when the thickness of the protective member is out of the above range and is too thick, the thickness of the protective member is unnecessarily thick compared to the desired structural stability, and the size of the battery cell is unnecessarily increased or the same size Compared to the battery cell, the capacity of the battery cell may be reduced.

In addition, at least one surface of the protective member facing the outer surface of the electrode assembly may have a structure in which an insulating coating layer is formed to prevent short circuit due to contact with the electrode assembly.

Accordingly, it is possible to effectively prevent a short circuit that may occur when the electrode assembly directly contacts the protection member.

In one specific example, the electrode assembly may have a structure wound in one direction while a positive electrode sheet, a negative electrode sheet, and a separator sheet interposed between the positive electrode sheet and the negative electrode sheet are stacked.

In another specific example, the electrode assembly may have a structure in which an anode, a cathode, and a separator interposed between the anode and the cathode are stacked.

In another specific example, the electrode assembly has a structure wound in one direction while two or more unit cells having a structure in which an anode, a cathode, and a separator interposed between the anode and the cathode are stacked are positioned on the separator sheet. Can be done.

That is, the electrode assembly constituting the battery cell has a rectangular structure in a plane, and if the positive terminal and the negative terminal can be formed in a structure protruding to one outer periphery, the structure is not greatly limited, and in detail, the winding It may be of a type structure, a stack type structure, or a stack & folding type structure.

Since the remaining structures of the battery cells except for the above configurations and structures are known in the art, detailed descriptions thereof will be omitted herein.

As described above, the battery cell according to the present invention is configured to include a protective member surrounding the outer periphery of the electrode assembly, so that it occurs due to the vacuum applied during the manufacturing process of the battery cell, and more specifically, the gas discharge process. It prevents the deformation of the shape of the outer surface of the battery cell, thereby reducing the defect rate of the product, and protecting the electrode assembly more safely against physical stimulation applied from the outside, thereby improving structural stability and damaging the electrode assembly. It is possible to effectively prevent the problem of deterioration in safety according to the protection member, and by securing a space to hold the electrolyte according to the special structure of the protection member, there is an effect of preventing the problem of performance degradation due to the decrease in the electrolyte solution.

1 is an exploded perspective view schematically showing the structure of a conventional pouch-type battery cell;
2 is a schematic diagram schematically showing the structure of a battery cell according to an embodiment of the present invention;
3 is a schematic diagram schematically showing a vertical cross-sectional structure of a battery cell according to A-A' of FIG. 2;
4 is a schematic diagram schematically showing the structure of various protective members of a battery cell according to another embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings according to an embodiment of the present invention, but the scope of the present invention is not limited thereto.

2 is a schematic diagram schematically showing the structure of a battery cell according to an embodiment of the present invention.

Referring to FIG. 2, the battery cell 200 has a structure in which the electrode assembly 210 and the protection member 220 are located in the receiving part 231 of the battery case 230.

The electrode assembly 210 has a rectangular structure in plan view and includes a positive terminal 211 and a negative terminal 212 protruding toward the upper outer periphery S1.

The battery case 230 includes an accommodating part 231 for accommodating the electrode assembly 210, and the outer periphery 232 is sealed by thermal fusion in a state in which the electrode assembly 210 is accommodated together with an electrolyte. .

A protective film 213 is attached to the upper and lower surfaces of the positive terminal 211 and the negative terminal 212 corresponding to the heat-sealed outer periphery 232 of the battery case 230 to improve sealing properties.

The protection member 220 is located between the outer surface of the electrode assembly 210 and the inner surface of the battery case 230 in the receiving part 231, and the positive terminal 211 and the negative electrode of the electrode assembly 210 in a plan view. The terminal 212 has a structure surrounding the remaining outer peripheries S2, S3, and S4 except for the protruding upper outer periphery S1.

The protection member 220 has a round structure in which both corner portions 221 and 222 of the electrode assembly 210 in the direction of the lower outer periphery (S3) facing the positive terminal 211 and the negative terminal 212 are round.

The corners of the electrode assembly 210 corresponding to the corner portions 221 and 222 of the protection member 220 having a round structure are in contact with the corner portions 221 and 222 of the protection member 220, respectively, and accordingly , Between the outer peripheries S2, S3, S4 of the electrode assembly 210 and the protective member 220, a space in which an electrolyte may be additionally located is formed.

Both end portions 223 and 224 of the protective member 220 adjacent to the upper outer periphery S1 from which the positive terminal 211 and the negative terminal 212 of the electrode assembly 210 protrude are, the electrode assembly 210 Compared to the upper outer periphery (S1) of the, it is located relatively outward, and is bent and extended in the inner direction where the electrode assembly 210 is located in a plane.

Accordingly, the electrode assembly 210 includes corner portions 221 and 222 formed in a round structure of the protection member 220 and both end portions 223 bent and extended in the receiving portion 231 of the battery case 230. Since the flow is prevented by the 224, it is possible to prevent damage to the positive terminal 211 and the negative terminal 212 due to the flow of the electrode assembly 210.

FIG. 3 is a schematic diagram schematically showing a vertical cross-sectional structure of a battery cell according to A-A' of FIG. 2.

Referring to FIG. 3, the height T1 of the protection member 220 in the vertical section is about 80% of the thickness T2 of the electrode assembly 210 corresponding thereto.

The width W1 of the protection member 220 is about 108% of the width W2 of the electrode assembly 210.

An insulating coating layer 240 is formed on the inner surface of the protective member 220 facing the outer surface of the electrode assembly 210 to prevent a short circuit due to contact with the electrode assembly 210.

4 is a schematic diagram schematically showing the structure of various protective members of a battery cell according to another embodiment of the present invention.

Referring to FIG. 4, the end portion 523 of the protective member 520 is located relatively outside the outer periphery (S5) of the electrode assembly 510 in which the positive and negative terminals protrude in a plane. In, so as to surround the edge 511 of the outer periphery (S5) of the electrode assembly 510, which is bent and extended (A) at an angle of 90 degrees in the direction of the electrode assembly 510, or the positive and negative terminals protrude, It is bent two or more times (B), or is bent and extended (C) to a length corresponding to the edge 511 of the outer periphery (S5) of the electrode assembly 510 from which the positive and negative terminals protrude.

Hereinafter, the present invention will be further described with reference to examples of the present invention, but the scope of the present invention is not limited thereto.

Battery cell manufacturing

<Example 1>

An electrode assembly having a structure in which a separator is interposed between the positive and negative electrodes, and the positive and negative terminals protrude from one outer periphery of the battery case, and the positive and negative terminals of the electrode assembly protrude. A protective member made of stainless steel was positioned between the electrode assembly and the receiving portion so as to surround the outer periphery except for the periphery. A primary battery cell was manufactured by sealing the outer periphery of the battery case in a state in which the electrode assembly was impregnated with an electrolyte, and the activation process was performed by charging and discharging the primary battery cell. A battery cell was manufactured by drilling a hole in the battery case of the primary battery cell in which the activation process was completed to remove gas generated therein by vacuum, and then removing the portion where the hole was punctured.

<Comparative Example 1>

The same battery cell as in Example 1 was manufactured, except that the protective member was not included.

<Experimental Example 1>

Of the outer surfaces of the battery cells prepared in Example 1 and Comparative Example 1, visually confirming whether or not the shape deformation occurred due to the vacuum applied during the gas removal process, except for the protruding portion of the electrode terminals. And the results are shown in Table 1.

Whether or not shape deformation occurs Example 1 X Comparative Example 1 O

As shown in Table 1, in the case of Example 1 including the protective member, the shape of the outer surface of the battery case did not change in the rest of the battery cell except for the protruding portions of the electrode terminals, whereas the protective member was included. In the case of Comparative Example 1 in which the electrode terminals are not protruded, it can be seen that the shape of the outer surface of the battery case is deformed in the rest of the electrode assembly except for the protruding portions.

Therefore, in the manufacturing process of the battery cell, when vacuum is applied during the degassing process, it is known that the protective member surrounding the outer periphery of the electrode assembly prevents shrinkage or deformation of the battery case, thereby reducing the defect rate of the product. I can.

<Experimental Example 2>

In the state in which the positive and negative terminals of the battery cells prepared in Example 1 and Comparative Example 1 were electrically connected to an external device, respectively, on the outer surface of the battery cell, on the right side of the outer periphery where the electrode terminals protruded in a plane shape. For the outer periphery located, it was checked whether or not an internal short circuit occurred after passing through the acicular member, and the results are shown in Table 2.

Whether there is an internal short circuit Example 1 X Comparative Example 1 O

As shown in Table 1, in the case of Example 1 including the protective member, when penetrating by the needle-shaped member, no internal short circuit occurred, whereas in the case of Comparative Example 1 not including the protective member, the needle-shaped member When penetrating by the needle-shaped member, it can be confirmed that an internal short circuit has occurred because the needle-shaped member directly contacts the electrode assembly.

Therefore, when the needle-shaped member passes through the outer periphery of the battery cell, the protective member surrounding the outer periphery of the electrode assembly prevents direct contact between the needle-shaped member and the electrode assembly, thereby preventing the internal short circuit of the battery cell and the resulting ignition. It can be seen that the risk of explosion can be prevented, and accordingly, structural stability and safety of the battery cell can be improved.

Although it has been described above with reference to the embodiments of the present invention and the drawings according to the embodiments, those of ordinary skill in the field to which the present invention belongs, it is possible to make various applications and modifications within the scope of the present invention based on the above contents. It will be possible.

Claims (15)

An electrode assembly consisting of a planar square structure and including a positive terminal and a negative terminal protruding toward an outer periphery of one side;
A battery case including a storage unit for accommodating the electrode assembly, and sealing the electrode assembly in a state in which the electrode assembly is received together with an electrolyte solution; And
A protection member disposed between the outer surface of the electrode assembly and the inner surface of the battery case in the receiving portion, and having a structure surrounding the rest of the outer periphery except for the outer periphery where the positive and negative terminals of the electrode assembly protrude in a plan view;
Including ,
The protection member is made of a metal or high strength plastic that is not reactive with an electrolyte,
The protection member has a round structure in which corner portions of the electrode assembly in a direction opposite to the positive terminal and the negative terminal are formed,
The radius of curvature of the round structure is from 5% to 5% based on the width of the electrode assembly, which is the distance between the outer peripheries of opposite sides of the electrode assembly, except for the outer periphery where the positive and negative terminals of the electrode assembly protrude. 30% of the size,
Both end portions of the protective member adjacent to the outer periphery from which the positive and negative terminals of the electrode assembly protrude are bent and extended in the direction of the electrode assembly on a plane,
The battery cell, characterized in that the end portions of both sides of the bent and extended protection member are located relatively outside the electrode assembly, in which the positive terminal and the negative terminal protrude in a plane. delete The battery cell according to claim 1, wherein the protection member is made of stainless steel. The battery cell according to claim 1, wherein the battery case is a pouch-shaped case comprising a metal layer and a resin layer. delete delete delete The battery cell according to claim 1, wherein both end portions of the protection member are bent and extended at an angle of 1 to 90 degrees with respect to a straight line parallel to the protruding directions of the positive and negative terminals. delete The battery cell according to claim 1, wherein both end portions of the protection member are bent two or more times so as to surround both side edges of the outer periphery of the electrode assembly in which the positive and negative terminals protrude in a plane. The battery cell according to claim 1, wherein both end portions of the protection member are bent and extended to a length corresponding to both corners of the outer periphery of the electrode assembly in which the positive and negative terminals protrude in a plane. . The battery cell according to claim 1, wherein the height of the protective member in the vertical section is 50% to 99% of the thickness of the electrode assembly corresponding thereto. The battery cell according to claim 1, wherein the width and length of the protection member are 101% to 130% of the width and length of the electrode assembly. The battery cell according to claim 1, wherein the thickness of the protective member is 500 micrometers to 2000 micrometers. The battery cell according to claim 1, wherein an insulating coating layer is formed on at least one surface of the protective member facing the outer surface of the electrode assembly to prevent short circuit due to contact with the electrode assembly.

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