Battery cell, battery module comprising same, and sealing device

Abstract

Provided is a battery cell including an electrode assembly and a pouch case for sealing the electrode assembly and an electrolyte together, in which: the pouch case includes a receiving portion in which the electrode assembly is received and a sealing portion provided outside the receiving portion and sealing the electrode assembly; the sealing part comprises a strong sealing area and a weak sealing area; and the sealing portion includes a discharge path formed by a weak sealing area and including an inlet on an inner surface of the sealing portion to be connected to the receiving portion and an outlet on an outer surface of the sealing portion to be integrally connected to the inlet.

Description

Technical Field

[0001] The present disclosure relates to a battery cell, a battery module including the battery cell, and a sealing device for manufacturing the battery cell, and more particularly, to a battery cell for smoothly discharging internal gas, a battery module, and a sealing device for manufacturing such a battery cell. This application claims priority to Korean Patent Application No. 10-2022-0181114 filed in Korea on December 21, 2022, the disclosure of which is incorporated herein by reference. Background Art

[0002] Secondary batteries have high applicability according to product groups and electrical characteristics such as high energy density, and thus are commonly used not only in portable devices but also in electric vehicles (EV) or hybrid electric vehicles (HEV) driven by power supplies. Such secondary batteries are gaining attention as new energy sources that improve eco-friendliness and energy efficiency, because they not only have the main advantage of significantly reducing the use of fossil fuels, but also do not generate byproducts from the use of energy.

[0003] In a general secondary battery structure, a pouch-type secondary battery has a structure in which an electrode assembly is housed in a pouch-shaped case to form a battery cell. A problem with conventional battery cells is that a heat-melting process is performed on the entire upper and lower cases of the pouch-shaped case, resulting in a firm joining of the entire pouch-shaped case, so that even if internal gas is generated due to expansion or the like, it cannot be properly discharged, and the generated internal gas continues to remain inside and accumulates.

[0004] If an external impact or an electrical short circuit occurs while the expansion phenomenon is maintained and accelerated due to this problem, a fatal defect may occur in which the battery cell explodes due to a chemical chain reaction with internal chemical components.

[0005] Furthermore, in conventional battery cells, when the pouch case cannot withstand the internal pressure of the gas and ruptures to discharge the gas, there is a problem of difficulty in predicting or controlling which part of the pouch case will rupture and in which direction the gas will be discharged. Such uncontrolled discharge may lead to safety issues for the secondary battery. Summary of the invention

[0006] Technical issues

[0007] The present disclosure aims to provide a battery cell capable of guiding internal gas generated inside a bag-shaped casing to be discharged at a specific position and in a specific direction.

[0008] The present disclosure also aims to provide a battery module including the battery cell.

[0009] The present disclosure also aims to provide a sealing device for manufacturing such a battery cell.

[0010] Technical Solution

[0011] A battery cell for solving the above problems according to an embodiment of the present disclosure includes: an electrode assembly and a bag-shaped casing for sealing the electrode assembly and an electrolyte together;

[0012] Wherein, the bag-shaped shell includes:

[0013] a receiving portion in which the electrode assembly is accommodated; and

[0014] a sealing portion disposed outside the receiving portion to seal the electrode assembly, and

[0015] Wherein, the sealing portion includes a strong sealing section and a weak sealing section, and a discharge path is formed by the weak sealing section in the sealing portion, and the discharge path includes an inlet located on the inner surface of the sealing portion to be connected to the receiving portion and an outlet located on the outer surface of the sealing portion to be integrally connected to the inlet.

[0016] The gas generated in the receiving part may be discharged to the outside of the receiving part through the discharge path.

[0017] The sealing portion may have: a first sealing portion, which extends in a first direction and in which the discharge path is formed; and a second sealing portion, which extends in a second direction intersecting the first direction, wherein the discharge path may include: at least one length discharge portion, which extends in the first direction; and a width discharge portion, which extends in the second direction and is connected to the length discharge portion.

[0018] The length of the first sealing portion in the first direction may be greater than the length of the second sealing portion in the second direction, and the length of the length discharge portion in the first direction may be greater than the length of the width discharge portion in the second direction.

[0019] A lead wire of the electrode assembly may extend through the second sealing portion.

[0020] The inlet may be located at one end of the first sealing portion, and the outlet may be located at the other end of the first sealing portion.

[0021] The sealing portion may further include: a third sealing portion extending in the first direction; and a fourth sealing portion extending in the second direction, wherein the discharge path may not be formed in the third sealing portion.

[0022] The sealing portion may include an inner resin layer, a metal layer covering the inner resin layer, and an outer resin layer covering the metal layer, wherein the inner resin layer may include the discharge path and an adhesive portion contacting the discharge path and sealing the electrode assembly, wherein the sealing strength of the discharge path may be less than the sealing strength of the adhesive portion.

[0023] The discharge path may have a thickness greater than a thickness of the adhesive portion.

[0024] The thickness of the metal layer may be constant, and the thickness of the outer resin layer may be constant.

[0025] A battery module according to an embodiment of the present disclosure for solving the above-mentioned other problems includes: a battery cell according to the above-mentioned embodiment of the present disclosure; and a module housing, which accommodates the battery cell, wherein each of the inlets of the battery cell is arranged side by side in one direction, and each of the outlets of the battery cell is arranged side by side in the one direction.

[0026] A sealing device for solving another problem mentioned above according to an embodiment of the present disclosure includes: an upper sealing tool, which applies pressure to the sealing part from the upper part of the sealing part included in the bag-like shell; and a lower sealing tool, which applies pressure to the sealing part from the lower part of the sealing part included in the bag-like shell, wherein at least one of the upper sealing tool and the lower sealing tool has a step formed to correspond to a discharge path, and the discharge path includes an inlet located on the inner surface of the sealing part and an outlet located on the outer surface of the sealing part to be integrally connected to the inlet.

[0027] A pressure applied to the sealing portion by a region where the step is formed may be smaller than a pressure applied to the sealing portion by a region where the step is not formed.

[0028] The body of at least one of the upper sealing tool and the lower sealing tool may have the step formed in an intaglio form on the surface contacting the sealing portion, so that the body thickness of the area where the step is formed may be smaller than the body thickness of the area where the step is not formed.

[0029] The sealing portion may have: a first sealing portion, which extends in a first direction and in which the discharge path is formed; and a second sealing portion, which extends in a second direction intersecting the first direction, wherein the discharge path may include: at least one length discharge portion extending in the first direction; and a width discharge portion extending in the second direction and connected to the length discharge portion, and wherein the step may be formed to correspond to the length discharge portion and the width discharge portion.

[0030] Beneficial Effects

[0031] In order to solve the above problems, a battery cell according to an embodiment of the present disclosure may include an electrode assembly and a bag-shaped shell for sealing the electrode assembly with an electrolyte. The bag-shaped shell includes: a receiving portion in which the electrode assembly is accommodated; and a sealing portion, which is arranged outside the receiving portion to seal the electrode assembly, wherein a discharge path may be formed in the sealing portion, the discharge path including an inlet located on the inner surface of the sealing portion to be connected to the receiving portion and an outlet located on the outer surface of the sealing portion to be integrally connected to the inlet.

[0032] Conventional battery cells have a problem that internal gas cannot be properly discharged even if it is generated due to expansion or the like, but the present disclosure can guide the internal gas to be discharged in a specific direction through a discharge path. In addition, by forming a longer discharge path along the long side of the bag-shaped shell, the cumulative flow rate value until the internal gas is discharged can be increased, and more internal gas can be trapped inside the bag-shaped shell. In addition, since the discharge path is formed in the existing bag-shaped shell, the discharge path does not require additional volume, so the remaining volume of the battery cell can be maximized.

[0033] In the battery module according to the present disclosure, the battery cells can be accommodated by aligning the discharge paths. Therefore, the internal gas of the battery cells can be guided to be discharged in a specific direction. Therefore, the safety of the battery module can be improved.

[0034] The sealing device according to the present disclosure may include a sealing tool having a step formed to correspond to a discharge path formed in a battery cell. By using the sealing device according to the present disclosure, the discharge path may be easily formed in the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure, and thus the present disclosure is not to be construed as being limited to the accompanying drawings.

[0036] Figure 1is a perspective view for describing a battery cell according to an embodiment of the present disclosure.

[0037] Figure 2 yes Figure 1 Enlarged cross-sectional view of area A and area B in FIG.

[0038] Figure 3 Is used to describe Figure 1 A plan view of a battery cell.

[0039] Figure 4 yes Figure 3 An enlarged plan view of area C.

[0040] Figure 5 It is along Figure 4 A cross-sectional view taken along line II'.

[0041] Figure 6 It is used to describe manufacturing Figure 1 A perspective view of a battery cell method.

[0042] Figure 7 Is used to describe Figure 6 A three-dimensional view of a sealing tool.

[0043] Figure 8 It is used to describe Figure 1 A three-dimensional view of a battery module with battery cells. DETAILED DESCRIPTION

[0044] The present disclosure will become more apparent by describing the preferred embodiments of the present disclosure in detail with reference to the accompanying drawings. The embodiments described herein are shown by way of example to help understand the present disclosure, and it should be understood that the present disclosure may be modified and implemented in various ways different from the embodiments described herein. In addition, in order to help understand the present disclosure, the accompanying drawings are not shown in actual proportion, but may exaggerate the size of some components.

[0045] Figure 1 is a perspective view for describing a battery cell according to an embodiment of the present disclosure, Figure 2 yes Figure 1 An enlarged cross-sectional view of region A and region B, and Figure 3 Is used to describe Figure 1 A plan view of a battery cell.

[0046] Reference Figure 1 , a battery cell 10 according to an embodiment of the present disclosure may include an electrode assembly 100 and a pouch case 200. The battery cell 10 may have a rectangular shape including long sides extending in a first direction X and short sides extending in a second direction Y intersecting the first direction X, and may have a thickness in a third direction Z perpendicular to the first direction X and the second direction Y.

[0047] The electrode assembly 100 may include a negative electrode, a positive electrode and a separator, wherein the negative electrode and the positive electrode are alternately arranged, and the separator may be placed between the negative electrode and the positive electrode. The electrode assembly 100 may be a stacked electrode assembly, a stacked / folded electrode assembly, or a roll-type electrode assembly. For example, a stacked electrode assembly may have a structure in which the positive electrode and the negative electrode of a unit cut into a predetermined size are stacked in sequence with a separator interposed therebetween, and a stacked / folded electrode assembly may have a structure in which a double battery cell or a full battery cell formed by stacking the positive electrode and the negative electrode cut into units of a predetermined size with a separator interposed therebetween is wound. The illustrated example is a roll-type, which may have a structure in which a laminate of a positive electrode, a separator, and a negative electrode on a sheet is wound.

[0048] In addition, the electrode assembly 100 may have a positive electrode connector extending from the positive electrode and a negative electrode connector extending from the negative electrode. The positive electrode connector and the negative electrode connector may be joined to the positive electrode lead 110 and the negative electrode lead 120, respectively, and the positive electrode lead 110 and the negative electrode lead 120 may extend to the outside to electrically connect the electrode assembly 100 and the external application device to each other. The illustrated example is a unidirectional battery. The positive electrode lead 110 and the negative electrode lead 120 extend parallel to each other from one side of the electrode assembly 100 to extend in one direction of the electrode assembly 100, thereby forming a unidirectional battery. As another example, the positive electrode lead 110 and the negative electrode lead 120 each extend from the opposite side of the electrode assembly 100 to extend in two directions of the electrode assembly 100, thereby forming a bidirectional battery.

[0049] The pouch case 200 can seal the electrode assembly 100 and the electrolyte together, and for this purpose, the pouch case 200 can include an upper case 210 and a lower case 220. The upper case 210 and the lower case 220 can be separate sheet members cut separately, or can also be used by folding and connecting sheet members into one body.

[0050] Reference Figure 2 , each of the upper case 210 and the lower case 220 may have a layered structure including an inner resin layer 211, a metal layer 212, and an outer resin layer 213. The metal layer 212 may cover the inner resin layer 211, and the outer resin layer 213 may cover the metal layer 212.

[0051] The inner resin layers 211 of the upper case 210 and the lower case 220 may contact each other. In order for the inner resin layers 211 to adhere to each other, the inner resin layers 211 may be formed of cast polypropylene (CPP), polypropylene (PP), or the like.

[0052] The metal layer 212 may be formed of an aluminum thin film to protect the electrode assembly 100 and the electrolyte, supplement the electrochemical properties of the battery cell 10, and improve heat dissipation. At this time, in order to ensure insulation between the battery cell 10 and the outside through the metal layer 212, the outer resin layer 213 may be formed of an insulating material such as polyethylene terephthalate (PET) resin, nylon resin, etc.

[0053] Reference Figure 1 and Figure 3 The pouch case 200 may be divided into a receiving part SDP and a sealing part SLP. The electrode assembly 100 may be accommodated in the receiving part SDP, and the sealing part SLP may be disposed at the periphery of the receiving part SDP so that the upper case 210 and the lower case 220 described above may contact each other to seal the electrode assembly 100.

[0054] The sealing portion SLP may have a first sealing portion SLP1 extending in the first direction X, a second sealing portion SLP2 extending in a second direction Y intersecting the first direction X, a third sealing portion SLP3 extending in the first direction X and opposite to the first sealing portion SLP1, and a fourth sealing portion SLP4 extending in the second direction Y and opposite to the second sealing portion SLP2.

[0055] For example, when the pouch case 200 has a rectangular shape, the first direction X may be a longitudinal direction forming a long side of the pouch case 200, and the second direction Y may be a width direction forming a short side of the pouch case 200. The positive lead 110 and the negative lead 120 extend through the second sealing portion SLP2.

[0056] The illustrated example is a case where the upper case 210 and the lower case 220 are separate sheet-like members so as to perform four-sided sealing. When the sheet-like members connected as one are folded and used, sealing can be omitted by allowing the side of the electrode assembly 100 to be in close contact with the folded portion, so that three-sided sealing can be performed. For example, the sealing portion SLP may consist of only the first sealing portion SLP1, the second sealing portion SLP2, and the fourth sealing portion SLP4, without the third sealing portion SLP3.

[0057] A variety of materials can be used as the positive electrode, negative electrode, and electrolyte of the battery cell, and generally, lithium-based oxides can be mainly used as the positive electrode, carbon-based materials can be used as the negative electrode, and organic solvent electrolytes containing lithium salts can be used as the electrolyte. In this case, if the battery is overcharged or the electrical environment changes suddenly, decomposition of the electrolyte may occur at the positive electrode and precipitation of lithium metal may occur at the negative electrode, and gas may be generated inside the receiving part SDP due to the heat generated by such chemical reactions.

[0058] In addition, organic solvents such as ethylene carbonate and propylene carbonate are used as electrolytes, and these organic solvents decompose at high temperatures to generate gas, which may cause the receiving part SDP to expand due to the resulting pressure increase. This expansion phenomenon may cause an electrical short circuit, and if an external impact is applied while expanding, the internal gas escapes to the outside, during which the occurrence of sparks or the like may cause fire, which is very dangerous.

[0059] The problem with conventional battery cells is that a hot-melt process is performed on the entire upper and lower shells of the bag-shaped shell, resulting in a firm joining of the entire bag-shaped shell. Therefore, even if internal gas is generated due to expansion, etc., the gas discharge position cannot be adjusted, resulting in discharge at any position, thereby causing electrolyte leakage, which may cause fatal defects such as battery cell fire and explosion.

[0060] For this reason, it becomes important to predict and control the direction of gas emission because the pouch-like casing cannot withstand the internal pressure of the gas and ruptures in the battery cell.

[0061] In order to solve the above-mentioned defects, a discharge path (eg, Figure 4 The first sealing portion SLP1 may include a strong sealing segment and a weak sealing segment, and the discharge path VP may be formed by the weak sealing segment. The strong sealing segment refers to a segment in which the seal is stronger than the surrounding area, and the weak sealing segment refers to a segment in which the seal is weaker than the surrounding area. The segment in which the seal is stronger than the surrounding area is sealed by the pressure of a sealing tool that is pressed tighter than the surrounding area. In the segment in which the seal is stronger than the surrounding area, the sealing strength (strength extended in two directions) of the sealing surface after sealing is also greater than the sealing strength of the surrounding area. The segment in which the seal is weaker than the surrounding area is sealed by the pressure of a sealing tool that is pressed lighter than the surrounding area. In the segment in which the seal is weaker than the surrounding area, the sealing strength of the sealing surface after sealing is also less than the sealing strength of the surrounding area. The strong sealing segment and the weak sealing segment are relative concepts, and the weak sealing segment refers to a segment in which the seal is weaker than the strong sealing segment. For example, the weak sealing segment may be a segment in which the sealing strength is 60% to 80% of that of the strong sealing segment.

[0062] According to the present disclosure, the internal gas can be guided to be discharged in a specific direction at a specific position through the discharge path VP. If the discharge position is random, there is a safety problem due to electrolyte leakage, etc. According to the present disclosure, the discharge position can be controlled at a specific position and in a specific direction of the battery cell 10, thereby improving safety.

[0063] Furthermore, as described later, by forming the discharge path VP longer along the long side direction of the sealing portion SLP, the cumulative flow value until the internal gas is discharged can be increased, and more internal gas can be trapped inside the bag-shaped housing 200. That is, by delaying the discharge time, the battery cell 10 can be used more safely for a longer time.

[0064] Furthermore, since the discharge path VP is formed in the existing pouch case 200 instead of providing a separate space for forming the discharge path VP, the discharge path VP does not require an additional volume, and thus it is possible to maximize the use of the remaining volume of the battery cell 10. That is, the receiving part SDP can be filled with the electrode assembly 100 as large as the receiving part SDP without providing a separate space to trap internal gas, thereby not losing battery capacity.

[0065] In the following, reference will be made to Figure 4 and Figure 5 The structure of the discharge path of the battery cell according to the embodiment of the present disclosure is described in more detail.

[0066] Figure 4 yes Figure 3 is an enlarged plan view of region C, and Figure 5 is along Figure 4 A cross-sectional view taken along line II'.

[0067] Reference Figure 3 and Figure 4 , a discharge path VP including an inlet IP, a first length discharge portion LVP1, a first width discharge portion WVP1, a second length discharge portion LVP2, a second width discharge portion WVP2, a third length discharge portion LVP3 and an outlet OP may be formed in the first sealing portion SLP1. The discharge path VP may include an inlet IP and an outlet OP integrally connected to the inlet IP. In one embodiment, the length discharge portion of the discharge path VP extends in the first direction X, and at least one length discharge portion may be included in the discharge path VP, while the width discharge portion of the discharge path VP extends in the second direction Y and may be connected to the length discharge portion. The number and position of the length discharge portions and the width discharge portions may be changed as needed. In one embodiment, the length of the first sealing portion SLP1 in the first direction X is greater than the length of the second sealing portion SLP2 in the second direction Y. In this case, the length of the length discharge portion in the first direction X is greater than the length of the width discharge portion in the second direction Y.

[0068] The lengths and widths of the first to third length discharge portions LVP1, LVP2, LVP3 may be equal to each other. The first width discharge portion WVP1 and the second width discharge portion WVP2 may also have the same length and width. By realizing the first to third length discharge portions LVP1, LVP2, LVP3 having the same length and width and the first width discharge portion WVP1 and the second width discharge portion WVP2 having the same length and width, the discharged internal gas may uniformly apply pressure to the discharge path VP, thereby improving the safety of the battery cell 10.

[0069] In one embodiment, the sealing portion SLP includes a first sealing portion SLP1 and a third sealing portion SLP3 located in the long axis direction of the battery cell 10. The discharge path VP may be formed only in the first sealing portion SLP1. That is, the discharge path may not be formed in the third sealing portion SLP3. Since the discharge path VP through which the internal gas is discharged is formed only in the first sealing portion SLP1, the internal gas can be guided to be discharged in a specific direction. However, the present disclosure is not limited thereto, and the discharge path VP may be further formed in the second sealing portion SLP2, the third sealing portion SLP3 and / or the fourth sealing portion SLP4 as needed.

[0070] In the first sealing part SLP1 formed with the discharge path VP, a portion other than the discharge path VP may be defined as an adhesive part ADS. The discharge path VP and the adhesive part ADS are included in the inner resin layer 211 of the sealing part SLP. The adhesive part ADS contacts the discharge path VP and may seal the electrode assembly 100.

[0071] In one embodiment, the sealing strength of the discharge path VP may be less than the sealing strength of the adhesive portion ADS. The discharge path VP may be a weak sealing section, and the adhesive portion ADS may be a strong sealing section. For example, the sealing strength of the discharge path VP may be 60% to 80% of the sealing strength of the adhesive portion ADS. As an example, the sealing strength of the adhesive portion ADS may be 0.2 MPa to 0.5 MPa, and the sealing strength of the discharge path VP may be 0.12 MPa to 0.4 MPa.

[0072] By making the sealing strength of the discharge path VP relatively smaller than that of the surrounding area, the above-mentioned internal gas can be guided to be discharged along the discharge path VP. Specifically, when the internal gas is generated and accumulated in the receiving part SDP, the internal gas opens the inlet IP of the discharge path VP with a lower sealing strength to allow the internal gas to stay in the corresponding space, thereby releasing the internal pressure, and then when more gas is generated and the internal pressure increases, the first length discharge part LVP1 connected to the inlet IP is opened to allow the internal gas to move to the corresponding space, thereby releasing the internal pressure. Thereafter, when more gas is generated, the internal pressure can be released by allowing the gas to move sequentially through the first width discharge part WVP1, the second length discharge part LVP2, the second width discharge part WVP3 and the third length discharge part LVP3 as described above, and the gas can finally be discharged to the outside through the outlet OP. In this way, the gas generated in the receiving part SDP is released to the outside of the receiving part SDP through the discharge path VP.

[0073] In one embodiment, the inlet IP may be located on the inner surface of the first sealing portion SLP1 to be connected to the receiving portion SDP. Even in the first sealing portion SLP1, the inner surface of the first sealing portion SLP1 indicates a side closer to the electrode assembly 100. The first length discharge portion LVP1 is connected to the inlet IP and may extend in the first direction X. The first width discharge portion WVP1 is connected to the first length discharge portion LVP1 and may extend in the second direction Y. The second length discharge portion LVP2 is connected to the first width discharge portion WVP1 and may extend in the first direction X. The second width discharge portion WVP2 is connected to the second length discharge portion LVP2 and may extend in the second direction Y. The third length discharge portion LVP3 is connected to the second width discharge portion WVP2 and may extend in the first direction X. The outlet OP is connected to the third length discharge portion LVP3 and may be located on the outer surface of the first sealing portion SLP1. Even in the first sealing portion SLP1, the outer surface of the first sealing portion SLP1 indicates a side away from the electrode assembly 100.

[0074] In this case, the length of the first length discharge portion LVP1 in the first direction X may be greater than the length of the first width discharge portion WVP1 in the second direction Y.

[0075] In one embodiment, the inlet IP may be located at one end of the first seal portion SLP1 in the longitudinal direction, and the outlet OP may be located at the other end opposite to the one end of the first seal portion SLP1. In other words, an odd number of discharge portions (e.g., Figure 4 The first to third length discharge portions LVP1, LVP2, LVP3 shown in the figure may also define an even number of width discharge portions (e.g., Figure 4The first width discharge portion WVP1 and the second width discharge portion WVP2 are shown).

[0076] The length of the first length discharge portion LVP1 in the first direction X is greater than the length of the first width discharge portion WVP1 in the second direction Y, and the inlet IP and the outlet OP are respectively located at both ends of the first sealing portion SLP1, so that the maximum cumulative flow rate value of the discharged internal gas is increased, thereby allowing more internal gas to be trapped inside the bag-like shell 200.

[0077] Reference Figure 4 and Figure 5 , the first sealing portion SLP1 may have a layered structure including an inner resin layer 211 , a metal layer 212 , and an outer resin layer 213 .

[0078] In one embodiment, the inner resin layer 211 may include a discharge path VP and an adhesive portion ADS. In other words, the discharge path VP may be formed in the inner resin layer 211. When viewed in a cross section, the thickness of the discharge path VP may be greater than the thickness of the adhesive portion ADS. Therefore, the sealing strength of the discharge path VP may be implemented to be less than the sealing strength of the adhesive portion ADS. For example, the thickness of the discharge path VP may be 105% to 120% of the thickness of the adhesive portion ADS.

[0079] Before sealing, the thickness of the inner resin layer 211 included in each of the upper shell 210 and the lower shell 220 may be the same and constant. When heated during sealing, the inner resin layer 211 of the upper shell 210 and the inner resin layer 211 of the lower shell 220 that are in contact with each other may melt and become fluid. In this case, when a greater pressure is applied to one part, the fluidized inner resin layer 211 moves to the side where less pressure is applied and gathers, so there may be a difference in the thickness of the inner resin layer 211 after the sealing is completed. The thickness of the inner resin layer 211 is thinner in the part where a greater pressure is applied during sealing, and the thickness of the inner resin layer 211 is thicker in the part where a smaller pressure is applied. The part with a greater pressure during sealing is a strong sealing section, and the part with a smaller pressure is a weak sealing section.

[0080] In one embodiment, the thickness of the metal layer 212 and the thickness of the outer resin layer 213 may be constant. Figure 5 As shown, when the discharge path VP is formed toward the upper case 210 , a step may be formed on the upper surface of the upper case 210 .

[0081] However, the present disclosure is not limited thereto. In an embodiment of the present disclosure, various structures capable of achieving a smaller sealing strength of the discharge path VP may be applied. For example, in another embodiment, the discharge path VP may be formed toward the lower shell 220, and in yet another embodiment, the discharge path VP may also be formed in both the upper shell 210 and the lower shell 220.

[0082] Figure 6 It is used to describe manufacturing Figure 1 A perspective view of a battery cell method, and Figure 7 Is used to describe Figure 6 A three-dimensional view of a sealing tool.

[0083] Reference Figure 6 and Figure 7 The battery cell 10 is composed of an electrode assembly 100 and a bag-shaped shell 200, wherein the electrode assembly 100 may include a general structure of a secondary battery cell (e.g., an electrode current collector, an electrode connector, etc.), and a first electrode lead 110 and a second electrode lead 120 serving as electrodes of the secondary battery can be attached to the electrode connectors of corresponding polarities by welding or the like.

[0084] like Figure 6 As shown in (a), the electrode assembly 100 may be accommodated in the receiving part SDP of the pouch case 200 so that a portion of the positive electrode lead 110 and the negative electrode lead 120 of the electrode assembly 100 are exposed to the outside. In addition, an electrolyte may be injected into the receiving part SDP together.

[0085] Afterwards, if Figure 6 As shown in (b), when the electrode assembly 100 is accommodated in the receiving portion SDP, the upper case 210 and the lower case 220 may be close to each other so that the positive electrode lead 110 and the negative electrode lead 120 are exposed to the outside, thereby forming the outer shape of the sealing portion SLP.

[0086] Afterwards, if Figure 6 As shown in (c), the outer peripheral surfaces of the upper case 210 and the lower case 220 may be sealed by a hot melt process. The hot melt process may be performed by applying heat and pressure to the sealing part SLP by the sealing device ST.

[0087] For example, the sealing device ST may include an upper sealing tool UST having a shape corresponding to the upper housing 210 of the first sealing part SLP1 and a lower sealing tool LST having a shape corresponding to the lower housing 220 of the first sealing part SLP1. The upper sealing tool UST may apply pressure to the first sealing part SLP1 from an upper portion of the first sealing part SLP1, and the lower sealing tool LST may apply pressure to the first sealing part SLP1 from a lower portion of the first sealing part SLP1.

[0088] The upper shell 210 and the lower shell 220 may be placed between the upper sealing tool UST and the lower sealing tool LST, and heat and pressure may be applied to form the sealing portion SLP. A step may be formed in at least one of the upper sealing tool UST and the lower sealing tool LST to correspond to the above reference Figure 4 The discharge path VP described. A body of at least one of the upper sealing tool UST and the lower sealing tool LST may have a step formed in an intaglio form on a surface contacting the sealing part SLP.

[0089] like Figure 7 As shown, a step STP may be formed in the upper sealing tool UST to correspond to the above reference Figure 4 For example, the step STP may be formed to correspond to the discharge path VP described above. Figure 4 Described are an inlet IP, a first length discharge portion LVP1, a first width discharge portion WVP1, a second length discharge portion LVP2, a second width discharge portion WVP2, a third length discharge portion LVP3, and an outlet OP.

[0090] In one embodiment, the body thickness of the upper sealing tool UST in the region where the step STP is formed may be formed to be smaller than the body thickness of the upper sealing tool UST in the region where the step STP is not formed. For example, the lower surface of the upper sealing tool UST in the region where the pressure is applied to the discharge path VP may be formed to be higher than the lower surface of the upper sealing tool UST in the region where the pressure is applied to the adhesive portion ADS. Therefore, the pressure applied to the first sealing portion SLP1 by the region where the step STP is formed may be smaller than the pressure applied to the first sealing portion SLP1 by the region where the step STP is not formed.

[0091] Although the existing sealing tool has an overall flat surface that contacts the bag-shaped housing, the sealing tool according to the present disclosure has steps so that the height of each position is different, and the sealing pressure and the corresponding sealing strength of each position can be adjusted accordingly. In this way, the discharge path VP can be easily formed in the battery cell 10 using the sealing device ST according to the present disclosure.

[0092] Figure 8 It is used to describe Figure 1 A three-dimensional view of a battery module with battery cells.

[0093] Reference Figure 8 The battery module 1 according to the embodiment of the present disclosure may include reference Figure 1 The battery cell 10 and the module case MC accommodating the battery cell 10 are described.

[0094] Although one or two to four battery cells are used per device in small mobile devices, medium to large devices such as vehicles require high output and large capacity. Therefore, a medium to large battery module having a battery pack in which a plurality of battery cells are electrically connected is used. A battery module 1 manufactured by electrically connecting battery cells 10 can be used as such a medium to large battery module. The battery cells 10 are connected to each other to ensure necessary power according to the use of power of the battery module 1 required.

[0095] In the battery module 1 according to one embodiment, the battery cells 10 may be accommodated in the module case MC by aligning the discharge paths VP. Figure 8 As shown, each of the inlets IP of the battery cells 10 can be arranged side by side in one direction, and each of the outlets OP can be arranged side by side in the one direction. Therefore, the internal gas of the battery cells 10 can be guided to be discharged in a specific direction. Therefore, the safety of the battery module 1 can be improved.

[0096] The present disclosure has been described above with respect to a limited number of embodiments and drawings, but the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations may be made thereto within the technical aspects of the present disclosure and the equivalent scope of the appended claims.

Claims

1. A battery cell, comprising an electrode assembly and a bag-shaped casing for sealing the electrode assembly and an electrolyte together, in, The bag-shaped housing comprises: a receiving portion in which the electrode assembly is accommodated; and a sealing portion disposed outside the receiving portion to seal the electrode assembly, and Wherein, the sealing portion includes a strong sealing section and a weak sealing section, and a discharge path is formed by the weak sealing section in the sealing portion, and the discharge path includes an inlet located on the inner surface of the sealing portion to be connected to the receiving portion and an outlet located on the outer surface of the sealing portion to be integrally connected to the inlet.

2. The battery cell according to claim 1, in, The gas generated in the receiving portion is discharged to the outside of the receiving portion through the discharge path.

3. The battery cell according to claim 1, in, The sealing portion comprises: a first sealing portion extending in a first direction and having the discharge path formed therein; and a second sealing portion extending in a second direction intersecting the first direction, Wherein, the discharge path includes: at least one length run extending in the first direction; and A width discharge portion extends in the second direction and is connected to the length discharge portion.

4. The battery cell according to claim 3, in, The length of the first sealing portion in the first direction is greater than the length of the second sealing portion in the second direction, and The length of the length discharge portion in the first direction is greater than the length of the width discharge portion in the second direction.

5. The battery cell according to claim 3, in, A lead wire of the electrode assembly extends through the second sealing portion.

6. The battery cell according to claim 3, in, The inlet is located at one end of the first sealing portion, and The outlet is located at the other end of the first sealing portion.

7. The battery cell according to claim 3, in, The sealing portion further comprises: a third sealing portion extending in the first direction; and a fourth sealing portion, the fourth sealing portion extending in the second direction, Wherein, the discharge path is not formed in the third sealing portion.

8. The battery cell according to claim 1, in, The sealing portion includes an inner resin layer, a metal layer covering the inner resin layer, and an outer resin layer covering the metal layer, wherein the inner resin layer includes the discharge path and an adhesive portion contacting the discharge path and sealing the electrode assembly, and Wherein, the sealing strength of the discharge path is smaller than the sealing strength of the adhesive portion.

9. The battery cell according to claim 8, in, The discharge path has a thickness greater than a thickness of the adhesive portion.

10. The battery cell according to claim 8, in, The thickness of the metal layer is constant, and The thickness of the outer resin layer is constant.

11. A battery module, comprising the battery cell according to any one of claims 1 to 10; and a module housing, the module housing accommodating the battery cell, in, Each of the inlets of the battery cells is arranged side by side in one direction, and Each of the outlets of the battery cells is arranged side by side in the one direction.

12. A sealing device for sealing a bag-like housing, the sealing device comprising: an upper sealing tool for applying pressure to the sealing portion from an upper portion of the sealing portion included in the bag-like housing; as well as a lower sealing tool that applies pressure to the sealing portion from a lower portion of the sealing portion included in the bag-like housing, wherein at least one of the upper sealing tool and the lower sealing tool has a step formed to correspond to a discharge path including an inlet on an inner surface of the sealing portion and an outlet on an outer surface of the sealing portion to be integrally connected to the inlet.

13. The sealing device according to claim 12, in, The pressure applied to the sealing portion by the region where the step is formed is smaller than the pressure applied to the sealing portion by the region where the step is not formed.

14. The sealing device according to claim 13, in, A body of at least one of the upper sealing tool and the lower sealing tool has the step formed in an intaglio form on a surface contacting the sealing portion, so that a body thickness of a region where the step is formed is smaller than a body thickness of a region where the step is not formed.

15. The sealing device according to claim 12, in, The sealing portion comprises: a first sealing portion extending in a first direction and having the discharge path formed therein; and a second sealing portion extending in a second direction intersecting the first direction, wherein the discharge path comprises: at least one length discharge portion extending in the first direction; and a width discharge portion extending in the second direction and connected to the length discharge portion, and The steps are formed to correspond to the length discharge portion and the width discharge portion.

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